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Sample records for lymphocyte culture mlc

  1. Nonspecific suppressor T cells cause decreased mixed lymphocyte culture reactivity in bone marrow transplant patients

    International Nuclear Information System (INIS)

    Harada, M.; Ueda, M.; Nakao, S.; Kondo, K.; Odaka, K.; Shiobara, S.; Matsue, K.; Mori, T.; Matsuda, T.

    1986-01-01

    Decreased reactivity in mixed lymphocyte culture (MLC) was observed in patients within 1 yr after allogeneic and autologous bone marrow transplantation. Suppressor activity of peripheral blood mononuclear cells (PBMC) from transplant patients was studied by adding these cells as modulator cells to a bidirectional MLC with cells from normal individuals. PBMC from transplant patients markedly suppressed MLC reactivity in a dose-dependent manner. Suppressor activity was present in cells forming rosettes with sheep erythrocytes. Treatment of modulator cells with monoclonal antibodies against T cell differentiation antigens (OKT8, OKIa1) and complement completely abolished suppression of MLC. Suppressor activity was unaffected by 30 Gy irradiation. Suppressor activity declined gradually after transplantation and was inversely correlated with MLC reactivity of each patient at a significant level (p less than 0.01). These observations suggest that OKT8+ Ia+ radioresistant suppressor T cells play a role in the development of decreased MLC reactivity observed during the early post-transplant period

  2. Proteolytically modified human beta 2-microglobulin augments the specific cytotoxic activity in murine mixed lymphocyte culture

    DEFF Research Database (Denmark)

    Nissen, Mogens Holst; Claësson, M H

    1987-01-01

    the endogenous production of interleukin 2 in the MLC culture; monoclonal antibody which reacts with both the native beta 2-m and M-beta 2-m molecule blocks the augmentation of cytotoxic T lymphocyte production induced by M-beta 2-m; murine as well as human MLC responder cells can proteolytically modify native......A proteolytically modified form of beta 2-microglobulin (beta 2-m) present in the serum of patients suffering from autoimmune, immunodeficient diseases and cancer has been reported in the literature. In the present study we show that human beta 2-m as well as the proteolytically modified human form...... (M-beta 2-m) bind to murine lymphocytes expressing H-2 class I antigens; M-beta 2-m, when added at day 0 and 1 of culture in nanomolar concentrations to a one-way murine allogeneic mixed lymphocyte culture (MLC) augments the generation of specific cytotoxic T lymphocytes; M-beta 2-m increases...

  3. Generation of cytotoxic T lymphocytes in vitro. VII. Suppressive effect of irradiated MLC cells on CTL response

    International Nuclear Information System (INIS)

    Fitch, F.W.; Engers, H.D.; Cerottini, J.C.; Bruner, K.T.

    1976-01-01

    Irradiated cells obtained from MLC at the peak of the CTL response caused profound suppression of generation of CTL when added in small numbers at the initiation of primary MLC prepared with normal spleen cells. The inhibitory activity of the MLC cells was not affected by irradiation (1000 rads) but was abolished by treatment with anti-theta serum and complement. The suppression was immunologically specific. The response of A (H-2/sup a/) spleen cells toward C3H (H-2/sup k/) alloantigens was suppressed by irradiated MLC cells obtained from MLC prepared with A spleen cells and irradiated C3H-stimulating cells, whereas the response of A spleen cells toward DBA/2 (H-2/sup d/) alloantigens was affected relatively little. However, if irradiated C3H x DBA/2F1 hybrid spleen cells were used to stimulate A spleen cells in MLC, addition of irradiated MLC cells having cytotoxic activity toward C3H antigens abolished the response to both C3H and DBA/2 antigens. The response to DBA/2 antigens was much less affected when a mixture of irradiated C3H and DBA/2 spleen cells was used as stimulating cells. Thus, the presence of MLC cells having cytotoxic activity toward one alloantigen abolished the response to another non-cross-reacting antigen only when both antigens were present on the same F1 hybrid-stimulating cells. This suppression of generation of CTL by irradiated MLC cells apparently involves inactivation of alloantigen-bearing stimulating cells as a result of residual cytotoxic activity of the irradiated MLC cells. This mechanism may be active during the decline in CTL activity noted in the normal immune response in vivo and in vitro

  4. Age- and dose-related alteration of in vitro mixed lymphocyte culture response of blood lymphocytes from A-bomb survivors

    International Nuclear Information System (INIS)

    Akiyama, Mitoshi; Zhou, Ou-Liang; Kusunoki, Yoichiro; Kyoizumi, Seishi; Kohno, Nobuoki; Akiba, Suminori; Delongchamp, R.R.

    1988-07-01

    The responsiveness of peripheral blood lymphocytes to allogenic antigens in mixed lymphocyte culture (MLC) was measured in 139 atomic bomb survivors. The study revealed a significant decrease in MLC with increasing dose of previous radiation exposure. This decline was remarkable in the survivors who were older than 15 at the time of the bomb (ATB). The results suggest a possible relationship between the recovery of T-cell-related function and the thymic function which processes mature T-cells for the immune system. Thus it may be that, in the advanced age ATB group, the thymus function has started to involute allowing less recovery of T-cell function compared to young survivors who have adequate processing T-cell activity. (author)

  5. Genotoxic effects of borax on cultured lymphocytes.

    Science.gov (United States)

    Pongsavee, Malinee

    2009-03-01

    The effect of borax on human chromosomes was analyzed in this study. Venous blood from 30 male students at Thammasat University, Thailand (age 18-25 years) was collected for lymphocyte cell cultures. This experiment was divided into two groups: the first group was the control group and the second group was the experimental group. The lymphocyte cells in the control group were cultured without borax. The experimental group was divided into four subgroups. The lymphocyte cells in each experimental subgroup were cultured with different concentrations of borax (0.1 mg/ml, 0.15 mg/ml, 0.2 mg/ml and 0.3 mg/ml). Human chromosomes were studied for abnormalities through Giemsa-staining and G-banding. The results show that the numbers of metaphase plates (the metaphase plate which contained 46 chromosomes; 46, XY) and metaphase chromosomes were reduced when lymphocyte cells were cultured with 0.15 mg/ml (57.2%), 0.2 mg/ml (50.8%) and 0.3 mg/ml (42.3%) concentrations of borax. There was a statistically significant difference between the control and experimental subgroups (p borax concentration experimental subgroup. This shows that borax (at 0.15, 0.2 and 0.3 mg/ml concentrations) affects the cell and human chromosomes (both numerical and structural abnormalities). Borax may cause human chromosome abnormalities and lead to genetic defects.

  6. The genotoxicity of sodium arsenite in human lymphocyte culture

    International Nuclear Information System (INIS)

    Elhabit, O.H.M.

    1995-01-01

    Sodium arsenite was tested for its clastogenic effect alone and in combination with x-irradiation on whole blood culture and on isolated lymphocyte culture. The results showed a significant difference in the yield of aberrations induced with respect to the culture time 48 hr whole blood culture showed significant increase in gaps and breaks whereas isolated lymphocytes culture showed significant inhibition of cell cycle and 75% of the lymphocytes were in first cell cycle at 72 hr. Arsenite showed co-mutagenicity with different doses of x-ray delivered immediately or few hours after treatment of the culture with SA. The results suggest that SA also is mutagenic at the dose level used and provide support for the indispensability of whole blood culture for evaluation of the in vivo effect any suspected mutagen. Using isolated lymphocytes appear to have problems leading to extensive cell cycle delay

  7. The Genotoxicity of Sodium Arsenite in Human Lymphocyte Culture

    International Nuclear Information System (INIS)

    El-Habit Ola, H.M.

    1998-01-01

    Sodium arsenite was tested for its clastogenic effect alone and on isolated lymphocyte culture. The results showed a significant difference in the yield of chromosome aberrations induced with respect to the culture time 48 h. Whole blood culture showed significant increase in gaps and breaks whereas isolated lymphocyte culture showed significant inhibition of cell cycle and 75% of the lymphocytes were in their first cell cycle at 72 hr. Arsenite showed co-mutagenicity with different doses of x-ray delivered immediately or few hours after treatment of the culture with S A. The results suggest that S A is also mutagenic at the dose level used and provide support for the indispensability of whole blood culture for evaluation of the in vivo effect of any suspected mustagen using isolated lymphocytes appear to have problems leading to extensive cell cycle delay

  8. Cell proliferation and radiosensitivity of cow lymphocytes in culture

    International Nuclear Information System (INIS)

    Modave, C.; Fabry, L.; Leonard, A.

    1982-01-01

    The harlequin-staining technique has been used to study, after PHA-stimulation, the cell proliferation of cow lymphocytes in culture and to assess the radiosensitivity in first mitosis cells. At the 48 h fixation time, only 34% of the cells are in first mitosis whereas 55% are already in second and 11% in third mitosis. The exposure of cow lymphocytes to 200 rad X-rays result in the production of 16% dicentric chromosomes in first mitosis cells [fr

  9. Growing B Lymphocytes in a Three-Dimensional Culture System

    Science.gov (United States)

    Wu, J. H. David; Bottaro, Andrea

    2010-01-01

    A three-dimensional (3D) culture system for growing long-lived B lymphocytes has been invented. The capabilities afforded by the system can be expected to expand the range of options for immunological research and related activities, including testing of immunogenicity of vaccine candidates in vitro, generation of human monoclonal antibodies, and immunotherapy. Mature lymphocytes, which are the effectors of adaptive immune responses in vertebrates, are extremely susceptible to apoptotic death, and depend on continuous reception of survival-inducing stimulation (in the forms of cytokines, cell-to-cell contacts, and antigen receptor signaling) from the microenvironment. For this reason, efforts to develop systems for long-term culture of functional, non-transformed and non-activated mature lymphocytes have been unsuccessful until now. The bone-marrow microenvironment supports the growth and differentiation of many hematopoietic lineages, in addition to B-lymphocytes. Primary bone-marrow cell cultures designed to promote the development of specific cell types in vitro are highly desirable experimental systems, amenable to manipulation under controlled conditions. However, the dynamic and complex network of stromal cells and insoluble matrix proteins is disrupted in prior plate- and flask-based culture systems, wherein the microenvironments have a predominantly two-dimensional (2D) character. In 2D bone-marrow cultures, normal B-lymphoid cells become progressively skewed toward precursor B-cell populations that do not retain a normal immunophenotype, and such mature B-lymphocytes as those harvested from the spleen or lymph nodes do not survive beyond several days ex vivo in the absence of mitogenic stimulation. The present 3D culture system is a bioreactor that contains highly porous artificial scaffolding that supports the long-term culture of bone marrow, spleen, and lymph-node samples. In this system, unlike in 2D culture systems, B-cell subpopulations developing

  10. Regulation of primary cytotoxic T lymphocyte responses generated during mixed leukocyte culture with H-2d identical Qa-1-disparate cells

    International Nuclear Information System (INIS)

    Huston, D.P.; Tavana, G.; Rich, R.R.; Gressens, S.E.

    1986-01-01

    Cytotoxic lymphocyte (CTL) responses are not usually generated during primary mixed leukocyte culture (MLC) with H-2 identical cells. Thus NZB mice are unusual in that their spleen cells do mount CTL responses during primary MLC with H-2d identical stimulator cells; the predominant target antigen for these NZB responses is Qa-1b. Considering the numerous immunoregulatory defects in NZB mice, we postulated that these NZB anti-Qa-1 primary CTL responses were due to an abnormality in T suppressor cell activity. Cellular interactions capable of suppressing NZB anti-Qa-1 primary CTL responses were investigated by using one-way and two-way MLC with spleen cells from NZB mice and other H-2d strains. Although H-2d identical one-way MLC with the use of NZB responders resulted in substantial CTL responses, only minimal CTL responses were detected from two-way MLC with the use of NZB spleen cells plus nonirradiated spleen cells from other H-2d mice. Thus the presence of non-NZB spleen cells in the two-way H-2d identical MLC prevented the generation of NZB CTL. Noncytotoxic mechanisms were implicated in the suppression of the NZB CTL responses during two-way MLC, because only minimal CTL activity was generated when NZB spleen cells were cultured with semiallogeneic, H-2d identical (e.g., NZB X BALB) F1 spleen cells. The observed suppression could be abrogated with as little as 100 rad gamma-irradiation to the non-NZB spleen cells. The phenotype of these highly radiosensitive spleen cells was Thy-1+, Lyt-1+, Lyt-2-, L3T4+. The functional presence of these cells in the spleens of semiallogeneic, H-2d identical F1 mice indicated that their deficiency in NZB mice was a recessive trait. These data suggest that NZB mice lack an L3T4+ cell present in the spleens of normal mice that is capable of suppressing primary anti-Qa-1 CTL responses

  11. Genotoxic damage in cultured human peripheral blood lymphocytes ...

    African Journals Online (AJOL)

    Falaq Naz

    2012-06-29

    Jun 29, 2012 ... Genotoxic damage in cultured human peripheral blood lymphocytes of oral ... catechol estrogens and quinines, via redox reactions causes oxidative damage to .... volume was prepared for each donor. About, 0.8 ml of cell sus .... duce the adverse effects of OCs, such as the reduction in the estrogen content.

  12. Investigation of cytogenetic activity of radioprotectors in human lymphocyte culture

    International Nuclear Information System (INIS)

    Egiazaryan, S.V.; Arutyunyan, R.M.

    1977-01-01

    Studied are the effects of the F-11 and F-37 indene preparations on chromosome aberrations induced in lymphocyte culture of peripheral human blood by thioTEP. Investigation into the action of the substance in euqimolar concentrations has not shown their protective effect. Indene preparations did not change the spectrum of chromosome aberrations induced by thioTEP as well as did not increase the level of chromosome aberrations in lumphocyte culture of human peripheral human blood

  13. Simple method for culture of peripheral blood lymphocytes of Testudinidae.

    Science.gov (United States)

    Silva, T L; Silva, M I A; Venancio, L P R; Zago, C E S; Moscheta, V A G; Lima, A V B; Vizotto, L D; Santos, J R; Bonini-Domingos, C R; Azeredo-Oliveira, M T V

    2011-12-06

    We developed and optimized a simple, efficient and inexpensive method for in vitro culture of peripheral blood lymphocytes from the Brazilian tortoise Chelonoidis carbonaria (Testudinidae), testing various parameters, including culture medium, mitogen concentration, mitotic index, culture volume, incubation time, and mitotic arrest. Peripheral blood samples were obtained from the costal vein of four couples. The conditions that gave a good mitotic index were lymphocytes cultured at 37°C in minimum essential medium (7.5 mL), with phytohemagglutinin as a mitogen (0.375 mL), plus streptomycin/penicillin (0.1 mL), and an incubation period of 72 h. Mitotic arrest was induced by 2-h exposure to colchicine (0.1 mL), 70 h after establishing the culture. After mitotic arrest, the cells were hypotonized with 0.075 M KCl for 2 h and fixed with methanol/acetic acid (3:1). The non-banded mitotic chromosomes were visualized by Giemsa staining. The diploid chromosome number of C. carbonaria was found to be 52 in females and males, and sex chromosomes were not observed. We were able to culture peripheral blood lymphocytes of a Brazilian tortoise in vitro, for the preparation of mitotic chromosomes.

  14. Selective effects of alpha interferon on human T-lymphocyte subsets during mixed lymphocyte cultures

    DEFF Research Database (Denmark)

    Hokland, M; Hokland, P; Heron, I

    1983-01-01

    Mixed lymphocyte reaction (MLR) cultures of human lymphocyte subsets with or without the addition of physiological doses of human alpha interferon (IFN-alpha) were compared with respect to surface marker phenotypes and proliferative capacities of the responder cells. A selective depression on the T...... T4 cells and decreased numbers of T4 cells harvested from IFN MLRs (days 5-6 of culture). In contrast, it was shown that the T8 (cytotoxic/suppressor) subset in MLRs was either not affected or slightly stimulated by the addition of IFN. The depression of the T4 cells by IFN was accompanied...... by a decrease in the number of activated T cells expressing Ia antigens. On the other hand, IFN MLRs contained greater numbers of cells expressing the T10 differentiation antigen. In experiments with purified T-cell subsets the IFN effect was exerted directly on the T4 cells and not mediated by either T8...

  15. Light microscope observation of circulating human lymphocytes cultured in vitro

    Directory of Open Access Journals (Sweden)

    Naila Francis Paulo de Oliveira

    2010-10-01

    Full Text Available The purpose of this work was to study the isolation and a light microscopy technique for cultured lymphocytes. Blood samples were obtained by venipuncture with an anticoagulant added and centrifuged in a Percoll density gradient to separate the leukocytes. Lymphocytes were placed in 25 cm ³ tissue culture flasks at 37ºC. After culturing, they were fixed and stained with the methods used for blood smears. Results showed that not all fixing solutions and stains were an equally good choice for cultured lymphocytes.Os linfócitos são células importantes do sistema imune e têm sido largamente utilizados em estudos morfológicos. Entretanto, a literatura sobre técnicas de preparação dessas células é escassa e antiga, especialmente para linfócitos cultivados in vitro. Portanto, o objetivo desse estudo foi relatar com detalhes as técnicas de isolamento e microscopia de luz de linfócitos mantidos em cultura. Amostras de sangue foram obtidas por punção venosa e centrifugadas em gradiente de densidade de Percoll, para separar os leucócitos. Os linfócitos foram mantidos em frascos de cultura de 25 cm³ a 37ºC. Após a cultura, as células foram fixadas e coradas de acordo com a metodologia utilizada para esfregaços sanguíneos. Nossos resultados mostraram que nem todos os fixadores e corantes utilizados para esfregaços sanguíneos são uma boa escolha para linfócitos cultivados in vitro.

  16. Human mixed lymphocyte cultures. Evaluation of microculture technique utilizing the multiple automated sample harvester (MASH)

    Science.gov (United States)

    Thurman, G. B.; Strong, D. M.; Ahmed, A.; Green, S. S.; Sell, K. W.; Hartzman, R. J.; Bach, F. H.

    1973-01-01

    Use of lymphocyte cultures for in vitro studies such as pretransplant histocompatibility testing has established the need for standardization of this technique. A microculture technique has been developed that has facilitated the culturing of lymphocytes and increased the quantity of cultures feasible, while lowering the variation between replicate samples. Cultures were prepared for determination of tritiated thymidine incorporation using a Multiple Automated Sample Harvester (MASH). Using this system, the parameters that influence the in vitro responsiveness of human lymphocytes to allogeneic lymphocytes have been investigated. PMID:4271568

  17. A rapid radioassay for human IgG produced in lymphocyte in vitro culture systems

    International Nuclear Information System (INIS)

    Weightman, D.R.; Shale, D.J.; Tomlinson, W.R.

    1981-01-01

    Protein A bearing Staphylococcus aureus was used to develop a solid-phase radioassay for IgG immunoglobulins. The assay was specifically optimised for use in vitro human lymphocyte culture work. Compared with a solid-phase radioimmunoassay for IgG produced in lymphocyte culture, this assay had a similar performance profile and the advantages of rapidity and technical ease. (Auth.)

  18. Effect of low dose x-irradiation on alloantigen sensitized and unsensitized lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Dohi, Kiyohiko; Yahata, Hiroshi; Fukuda, Yasuhiko; Asahara, Toshimasa; Ono, Eiji; Ezaki, Haruo

    1984-12-01

    The effect of local graft irradiation on immune response in allograft in which acute rejection occurs was studied using an in vitro model. Unidirectional mixed lymphocyte culture (MLC) was used as the in vitro model of acute rejection. 150 and 300 rad x-irradiation suppressed mixed lymphocyte reaction (MLR) but did not cell-mediated-lympholysis (CML) of unsensitized lymphocytes. X-irradiated alloantigen sensitized cells (ASC) generated in 6-day MLC suppressed MLR and CML of unsensitized lymphocytes. Suppressive effects of x-irradiated ASC were of the same degree by x-irradiation doses of 150-500 rad. Suppressive effect of x-irradiation was maintained for only a short period after x-irradiation. Potential function of suppressor precursor cells among unsensitized lymphocytes was abolished by x-irradiation of 300 rad. (author).

  19. T-cell activation. VI. Inhibitory and stimulatory effects of anti-major histocompatibility complex class I antibodies in allogeneic mixed lymphocyte culture

    DEFF Research Database (Denmark)

    Röpke, M; Röpke, C; Claesson, Mogens Helweg

    1993-01-01

    Murine T splenocytes stimulated in primary allogeneic mixed lymphocyte culture (MLC) were incubated with soluble anti-major histocompatibility complex (MHC) class I monoclonal antibodies. These antibodies induced inhibition in the cytotoxicity of the responding population and this inhibition...... was not dependent on the domain on class I molecules recognized by the antibodies. Cross-reactivity of the antibodies between the responder and stimulating cell population caused a marked reduction in the inhibitory effect compared to systems where no such cross-reactivity was present. Saturating levels...... of the antibodies caused a reduction in generation of T-cell cytotoxicity, whereas low concentrations stimulated the same response. These results demonstrate that the MHC class I molecules of T cells are of significant importance in antigen-induced signal transduction....

  20. MANUAL LOGIC CONTROLLER (MLC)

    OpenAIRE

    Claude Ziad Bayeh

    2015-01-01

    The “Manual Logic Controller” also called MLC, is an electronic circuit invented and designed by the author in 2008, in order to replace the well known PLC (Programmable Logic Controller) in many applications for its advantages and its low cost of fabrication. The function of the MLC is somewhat similar to the well known PLC, but instead of doing it by inserting a written program into the PLC using a computer or specific software inside the PLC, it will be manually programmed in a manner to h...

  1. In vitro interactions of lymphocytes and cultured cells from beagles with plutonium-induced bone tumors

    International Nuclear Information System (INIS)

    Frazier, M.E.; Lund, J.E.; Busch, R.H.

    1976-01-01

    Cell cultures have been prepared from lung and bone tumors arising in beagle dogs following exposure to inhaled plutonium. Evaluation of the cultured cells by commonly applied criteria (i.e., cell morphology, lack of contact inhibitory mechanisms, cloning efficiency, growth in soft agar, and tumor production in vivo) indicated that tumor cells were being grown in culture. Blood leukocytes and peripheral lymphocytes from beagle dogs were tested for cytotoxic effects against several cell cultures. Lymphocytes from normal dogs or dogs with unrelated tumors would not kill the bone tumor cells unless monocytes (macrophage) were present, in which case the leukocyte preparation was capable of mounting de novo cytotoxic immune reactions after 3 to 5 days in culture. In contrast, the dogs with plutonium-induced bone tumors had circulating lymphocytes that appeared to have undergone presensitization to bone-tumor-distinctive antigens in vivo. Consequently these lymphocytes interacted with cultured cells promptly after encounter in vitro

  2. Inhibitory effect of mycoplasma-released arginase. Activity in mixed-lymphocyte and tumour cell cultures

    DEFF Research Database (Denmark)

    Claesson, M H; Tscherning, T; Nissen, Mogens Holst

    1990-01-01

    inhibition can be reversed by addition of excess arginine to the culture medium. Antisera raised against non-fermenting, but not against fermenting, mycoplasma species block the inhibitory effect of MAE. SDS-PAGE separation of MAE disclosed a broad band at 60 kDa which contained arginase activity when...... assayed in MLC and cell proliferation culture. SDS-PAGE followed by western blotting and reaction with antisera raised against non-fermenting mycoplasma species demonstrated a band at 43 kDa common for these micro-organisms....

  3. Co-Culturing of Multipotent Mesenchymal Stromal Cells with Autological and Allogenic Lymphocytes.

    Science.gov (United States)

    Kapranov, N M; Davydova, Yu O; Gal'tseva, I V; Petinati, N A; Bakshinskaitė, M V; Drize, N I; Kuz'mina, L A; Parovichnikova, E N; Savchenko, V G

    2018-03-01

    We studied the effect of autologous and allogeneic lymphocytes on multipotent mesenchymal stromal cells in co-culture. It is shown that changes in multipotent mesenchymal stromal cells and in lymphocytes did not depend on the source of lymphocytes. Contact with lymphocytes triggers expression of HLA-DR molecules on multipotent mesenchymal stromal cells and these cells lose their immune privilege. In multipotent mesenchymal stromal cells, the relative level of expression of factors involved in immunomodulation (IDO1, PTGES, and IL-6) and expression of adhesion molecule ICAM1 increased, while expression of genes involved in the differentiation of multipotent mesenchymal stromal cells remained unchanged. Priming of multipotent mesenchymal stromal cells with IFN did not affect these changes. In turn, lymphocytes underwent activation, expression of HLA-DR increased, subpopulation composition of lymphocytes changed towards the increase in the content of naïve T cells. These findings are important for cell therapy.

  4. Growth of human T lymphocyte colonies from whole blood: culture requirements and applications

    International Nuclear Information System (INIS)

    Knox, S.J.; Wilson, F.D.; Greenberg, B.R.; Shifrine, M.

    1982-01-01

    Growth of human lymphocyte colonies from whole blood following stimulation with PHA, Con A, or PPD is described. Individual colony cells were identified as T lymphocytes on the basis of surface marker and enzyme cytochemical characterizations. Colony formation increased as a power function over a wide range of cell concentrations above a critical minimal concentration. The whole blood culture system eliminates possible selective effects of lymphocyte colony techniques utilizing gradient-enriched lymphocyte fractions and more closely approximates the in vivo milieu. The whole blood colony method is more sensitive for the detection of low-level radiation effects on lymphocytes than widely used tests that measure 3 H-thymidine incorporation. In preliminary studies, researchers used the whole blood method to determine the relative radiosensitivity of lymphocytes from humans with various hematopoietic disorders, and observed abnormalities in mitogen responsiveness and colony formation in some of the patient groups. This method has wide application for studies in cellular and clinical immunology

  5. Addition of exogenous cytokines in mixed lymphocyte culture for selecting related donors for bone marrow transplantation

    Directory of Open Access Journals (Sweden)

    Jeane Eliete Laguila Visentainer

    Full Text Available CONTEXT: Mixed lymphocyte culturing has led to conflicting opinions regarding the selection of donors for bone marrow transplantation. The association between a positive mixed lymphocyte culture and the development of graft-versus-host disease (GVHD is unclear. The use of exogenous cytokines in mixed lymphocyte cultures could be an alternative for increasing the sensitivity of culture tests. OBJECTIVE: To increase the sensitivity of mixed lymphocyte cultures between donor and recipient human leukocyte antigen (HLA identical siblings, using exogenous cytokines, in order to predict post-transplantation GVHD and/or rejection. TYPE OF STUDY: Prospective study. SETTING: Bone Marrow Transplantation Unit, Universidade Estadual de Campinas. PARTICIPANTS: Seventeen patients with hematological malignancies and their respective donors selected for bone marrow transplantation procedures. PROCEDURES: Standard and modified mixed lymphocyte culturing by cytokine supplementation was carried out using donor and recipient cells typed for HLA. MAIN MEASUREMENTS: Autologous and allogenic responses in mixed lymphocyte cultures after the addition of IL-4 or IL-2. RESULTS: In comparison with the standard method, average responses in the modified mixed lymphocyte cultures increased by a factor of 2.0 using IL-4 (p < 0.001 and 6.4 using IL-2 (p < 0.001, for autologous donor culture responses. For donor-versus-recipient culture responses, the increase was by a factor of 1.9 using IL-4 (p < 0.001 and 4.1 using IL-2 (p < 0.001. For donor-versus-unrelated culture responses, no significant increase was observed using IL-4, and a mean response inhibition of 20% was observed using IL-2 (p < 0.001. Neither of the cytokines produced a significant difference in the unrelated control versus recipient cell responses. CONCLUSION: IL-4 supplementation was the best for increasing the mixed lymphocyte culture sensitivity. However, IL-4 also increased autologous responses, albeit less

  6. Effect of Vibrio cholerae neuraminidase on the mitogen response of T lymphocytes. I. Enhancement of macrophage T-lymphocyte cooperation in concanavalin-A-induced lymphocyte activation.

    Science.gov (United States)

    Knop, J

    1980-12-01

    Vibrio cholerae neuraminidase (VCN) enhances the immune response of lymphocytes in various systems, such as antigen- and mitogen-induced blastogenesis, mixed lymphocyte culture (MLC) and tumor-cell response. We used macrophage-depleted and reconstituted murine lymph-node T-cells to investigate the effect of VCN on macrophage-T-lymphocyte co-operation in Con-A-induced lymphocyte activation. In unfractionated lymph-node cells VCN enhanced the Con-A-induced lymphocyte activation as measured by 3H-thymidine (3H-dThd) incorporation. Removing macrophages from the cells resulted in a significantly diminished response. In addition the enhancing effect of VCN was greatly reduced. Reconstitution of the lymphocyte cultures with macrophages in increasing numbers and from various sources rstored the lymphocyte response and the enhancing effect of VCN. VCN proved to be most efficient in cultures reconstituted with normal peritoneal macrophages. Some effect was also observed using bone-marrow-derived (BM) macrophages. However, higher numbers of normal PE macrophages in the presence of VCN inhibited lymphocyte activation, and inhibition by thioglycollate-broth-induced macrophages was considerably increased by VCN. These results suggest that VCN acts by increasing the efficiency of macrophage-T lymphocyte interaction.

  7. Immunoglobulin production in human mixed lymphocyte cultures: implications for co-cultures of cells from patients and healthy donors

    International Nuclear Information System (INIS)

    Ruemke, H.C.; Terpstra, F.G.; Huis, B.; Out, T.A.; Zeijlemaker, W.P.

    1982-01-01

    When human peripheral blood lymphocytes (PBL) are cultured in the presence of irradiated allogeneic lymphocytes, the resulting mixed lymphocyte reaction (MLR) leads to the secretion into the supernatant of substantial amounts of IgM and IgG, derived from nonirradiated responder B lymphocytes. Our data indicate that stimulation to Ig production by responder B cells may result from different types of of interactions. First, B cells and monocytes among the irradiated stimulator cells activate T responder B cells to produce Ig; second, ''responder'' B cells activate irradiated ''stimulator'' T cells, leading to a ''helper'' signal, back to the responder B cells and leading to Ig production. The latter system is radiosensitive, because allogeneic T cells, irradiated at a dose of 4000 rad or more, failed to induce Ig production by responder B cells. In some combinations of human allogeneic lymphocytes, the co-culture of the cells leads to inhibition of Ig production, both in the presence and in the absence of PWM. Thus, co-culture of allogeneic cells may cause ''positive'' as well as ''negative'' allogeneic effects. The implications of these findings for the interpretation of co-cultures that are aimed at establishing defects in lymphocytes from patients with, for example, immunodeficiencies, who fail to produce Ig in the presence of PWM are discussed

  8. New chicken Rfp-Y haplotypes on the basis of MHC class II RFLP and MLC analyses

    DEFF Research Database (Denmark)

    Juul-Madsen, H R; Zoorob, R; Auffray, C

    1997-01-01

    New chicken Rfp-Y haplotypes were determined by the use of restriction fragment length polymorphism (RFLP) and mixed lymphocyte culture (MLC) in four different chicken haplotypes, B15, B19, B21, B201. The RFLP polymorphism was mapped to the Rfp-Y system by the use of a subclone (18.1) which maps...... near a polymorphic lectin gene located in the Rfp-Y system and DNA from families with known segregation of the implicated RFLP polymorphism. For the first time it is shown that major histocompatibility complex class II genes in the Rfp-Y system have functional implications. Sequence information...

  9. Manifestation of radiaton injury of human lymphocytes using PHA mitogenic stimulation in different culture systems

    International Nuclear Information System (INIS)

    Horky, J.

    1986-01-01

    The proliferative response of human lymphocytes to phytohemagglutinin in vitro is affected by X-irradiation. Dose-related changes in mitogenic stimulation of irradiated lymphocytes were compared for two culture systems - the cultivation of separated lymphocytes and the cultivation of whole blood. In the whole blood cultures, the proliferative activity of stimulated lyphocytes was markedly and reproducibly depressed by irradiation. An exponential curve could be fitted to the values of mitogenic response within a dose range from 0 to 2.5 Gy with high correlation. In a modified test where the mitogenic stimulus was given after a 24 h delay, depression in the response was even more pronounced. Radiosensitivity of human lymphocytes as determined by means of mitogenic stimulation in the whole blood cultures appears to be a characteristic individual feature. The mean D 37 value of the radiation-induced depression in mitogenic response in a group of 20 healthy donors was 2.5 Gy in the standard test and 2.0 Gy in the test with a delayed mitogenic stimulus. In contrast, the data obtained from separated lymphocyte cultures were characterized by a high degree of test-to-test variability and by much lower radiosensitivity. The possible mechanisms of these distinctive manifestations of the same primary radiation injury are discussed. (author) 3 tabs., 2 figs., 12 refs

  10. Assessment of in vitro genotoxic and cytotoxic effects of flurbiprofen on human cultured lymphocytes.

    Science.gov (United States)

    Timocin, Taygun; Ila, Hasan Basri; Dordu, Tuba; Husunet, Mehmet Tahir; Tazehkand, Mostafa Norizadeh; Valipour, Ebrahim; Topaktas, Mehmet

    2016-01-01

    Flurbiprofen is non-steroidal anti-inflammatory drug which is commonly used for its analgesic, antipyretic, and anti-inflammatory effects. The purpose of the study was to explore the genotoxic and cytotoxic effects of flurbiprofen in human cultured lymphocytes by sister chromatid exchange, chromosome aberration, and cytokinesis-blocked micronucleus tests. 10, 20, 30, and 40 μg/mL concentrations of flurbiprofen (solvent is DMSO) were used to treatment of human cultured lymphocytes at two different treatment periods (24 and 48 h). Flurbiprofen had no significant genotoxic effect in any of these tests. But exposing to flurbiprofen for 24 and 48 h led to significant decrease on proliferation index, mitotic index, and nuclear division index (NDI). Also, all decreases were concentration-dependent (except NDI at 24 h treatment period). Consequently, the findings of this research showed that flurbiprofen had cytotoxic effects in human blood lymphocytes.

  11. Effects of cyclophosphamide on in vitro human lymphocyte culture and mitogenic stimulation

    International Nuclear Information System (INIS)

    Sharma, B.S.

    1983-01-01

    Cyclophosphamide (CY) has been reported to be inactive in vitro under certain conditions. In the present study, CY was tested for its ability to inhibit human lymphocyte proliferation and to modulate lymphocyte response to mitogens in vitro. The inhibition of or the increase in 3 H-thymidine incorporation in mitogen-stimulated and unstimulated lymphocytes by CY was used as a measure of CY activity in vitro. The results demonstrate that lymphocytes from 10 different persons had a mean decrease of 74% in 3 H-thymidine incorporation in the presence of CY (P less than 0.005). The effect was maximal at a concentration of 160 micrograms/ml. A mean inhibition of 35 and 55% was caused by 10 and 40 micrograms/ml concentrations of CY, respectively. CY also was able to reduce the number of viable cells during 5 days in culture and had a profound effect on mitogen stimulation of lymphocytes. In all cases, CY modulated the stimulation of lymphocytes by phytohemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM) either by augmenting or suppressing the responses. At low concentrations (10 micrograms/ml) it augmented mitogenic stimulation by 46 to 281%. At higher concentrations (20 to 160 micrograms/ml), CY had a suppressive effect with a maximum suppression of 99%. The CY-induced immunomodulation is perhaps caused by its action on the regulatory T cells. When tested in vitro, CY had inhibitory activity on T cells

  12. Protective effect of allium sativum ethanol extract on cultured human lymphocytes against electron beam radiation

    International Nuclear Information System (INIS)

    Rao, Shama; Shetty, Sukanya; Suchetha Kumari; Madhu, L.N.

    2013-01-01

    The development of radioprotective agent has been the subject of intense research because exposure to ionizing radiation causes DNA damage which may cause mutation and ultimately leads to cancer, on the other hand radiotherapy has become an integral part in treatment of cancer which uses ionizing radiations like X rays, gamma rays to kill the cancer cells. Amifostine is a well-known radioprotector which is clinically approved. There are many other radioprotectors like cysteine, cystamine, serotine but they are not used because of its normal tissue toxicity. Allium sativum is commonly known as garlic which has already been reported for its medicinal properties. In this study we evaluated radioprotection property of Allium sativum on DNA damage caused by electron beam radiation in cultured human lymphocytes. Allium sativum ethanol extract was used for this study. Cell viability was performed by MTT assay. DNA damage was assessed by comet assay parameters. The cultured lymphocytes were incubated with different concentrations 10, 50 and 100 μg/mL of Allium sativum extracts for 2, 4, 6 and 24 hour time intervals. Treatment of lymphocytes with various concentration of Allium sativum extract resulted in significant decrease in the level of DNA damage (Percentage tail DNA 6%) and increase in cell viability 93% (p>0.05) compare to the radiation control group. Results of this study revealed that Allium sativum protects cultured lymphocytes when exposed to electron beam radiation at its sub lethal dose. (author)

  13. Isolation and Purification of an Early Pregnancy Factor–Like Molecule from Culture Supernatants Obtained from Lymphocytes of Pregnant Women

    OpenAIRE

    Aranha, Clara; Natraj, Usha; Iyer, K. S.; Shahani, Savitri

    1998-01-01

    Purpose:Our purpose was to determine whether lymphocytes synthesize proteins during pregnancy, to observe whether one of the proteins synthesized has early pregnancy factor (EPF)–like activity and to isolate and purify this molecule from culture supernatants obtained from stimulated lymphocytes of pregnant women.

  14. In Vitro Genotoxic Effects of Four Helichrysum Species in Human Lymphocytes Cultures

    OpenAIRE

    Erolu, Erhan H; Hamzaolu, Ergin; Aksoy, Ahmet; Budak, Ümit; Özkul, Yusuf

    2010-01-01

    Helichrysum sanguineum, Helichrysum pamphylicum, Helichrysum orientale, Helichrysum noeanum (Asteraceae) are medicinal plants. For centuries, they have been used as tea in Turkey because of their medicinal properties. So far no scientifc evidence has been found in a literature survey regarding the genotoxic effects of these plants. This work evaluated the genotoxic effects on human lymphocyte cultures induced by methanol extracts of these plants, assayed in different concentrations (0.01, 0.0...

  15. Differential Micronuclei Induction in Human Lymphocyte Cultures by Imidacloprid in the Presence of Potassium Nitrate

    Directory of Open Access Journals (Sweden)

    Polychronis Stivaktakis

    2010-01-01

    Full Text Available Humans are exposed to pesticides as a consequence of their application in farming or their persistence in a variety of media, including food, water, air, soil, plants, animals, and smoke. The interaction of pesticides with environmental factors may result in the alteration of their physicochemical properties. Square wave cathodic stripping voltammetry (SW-CSV, a technique that simulates electrodynamically the cellular membrane, is used to investigate whether the presence of potassium nitrate (KNO3 in the culture medium interferes with the genotoxic behavior of imidacloprid. The cytokinesis block micronuclei (CBMN method is used to evaluate imidacloprid's genotoxicity in the absence or presence of KNO3 in the culture medium and, as a consequence, its adsorption by lymphocytes. Comparing micronuclei (MN frequencies in control and imidacloprid-treated blood cell cultures, statistically significant differences were not detected. KNO3 did not induce MN frequencies compared to control. Statistically significant differences in MN frequencies were observed when blood cell cultures were treated with imidacloprid in the presence of increasing concentrations of KNO3. SW-CSV revealed that by increasing KNO3 molarity, imidacloprid's concentration in the culture medium decreased in parallel. This finding indicates that imidacloprid is adsorbed by cellular membranes. The present study suggests a novel role of a harmless environmental factor, such as KNO3, on the genotoxic behavior of a pesticide, such as imidacloprid. KNO3 rendered imidacloprid permeable to lymphocytes, resulting in elevated MN frequencies.

  16. [Effects of oil-refining microbes (genus Acinetobacter) on cytogenetical structures of human lymphocytes in cell cultures].

    Science.gov (United States)

    Il'inskikh, N N; Il'inskikh, E N; Il'inskikh, I N

    2012-01-01

    The objective of this study was to assess ability of oil-refining bacteria Acinetobacter calcoaceticus and A. valentis to induce karyopathological abnormalities and chromosomal aberrations in human lymphocyte cultures. It was found that the cultures infected with A. calcoaceticus showed significantly high frequencies of cytogenetical effects and chromosomal aberrant cells as compared to the intact cultures and cultures infected with A. valentis. The most of chromosomal aberrations, mainly chromatid aberrations, were located in 1 and 2 chromosomes. Moreover, the aberrations were detected in some specific chromosome areas. Abnormalities of mitotic cell division and nucleus morphology were determined in lymphocyte cultures infected with A. calcoaceticus. There were found significantly high frequencies of cells with micronuclei, nucleus protrusions, anaphase or metaphase chromosome and chromosomal fragments lagging as well as multipolar and C-mitoses. Thus, the oil-refining bacteria A. calcoaceticus in contrast to A. valentis demonstrated strong genotoxic effects in human lymphocyte cultures in vitro.

  17. The cytogenetic effects of black tea and green tea on cultured human lymphocytes

    Directory of Open Access Journals (Sweden)

    Halil Erhan Eroğlu

    2011-12-01

    Full Text Available In this study, the cytogenetic effects of black tea and green tea were determined in cultured peripheral blood lymphocytes. Results showed that black tea and green tea induced the mitotic and replication indexes and decreased micronuclei. But these data were not statistically significant for green tea. The effects of black tea on the micronucleus formation and mitotic index were statistically significant. The decrease in micronucleus counts indicated that black tea and green tea had considerable anticlastogenic and antigenotoxic effects as observed in vitro in human lymphocytes. Thus, it could be concluded that tea polyphenols protected the normal cells from genotoxic or carcinogenic agents, which indicated the therapeutic and antioxidative role of catechins, flavonoids or other tea compounds.

  18. Culture of normal human blood cells in a diffusion chamber system II. Lymphocyte and plasma cell kinetics

    International Nuclear Information System (INIS)

    Chikkappa, G.; Carsten, A.L.; Chanana, A.D.; Cronkite, E.P.

    1979-01-01

    Normal human blood leukocytes were cultured in Millipore diffusion chambers implanted into the peritoneal cavities of irradiated mice. The evaluation of survival and proliferation kinetics of cells in lymphyocytic series suggested that the lymphoid cells are formed from transition of small and/or large lymphocytes, and the lymphoblasts from the lymphoid cells. There was also evidence indicating that some of the cells in these two compartments are formed by proliferation. The evaluation of plasmacytic series suggested that the plasma cells are formed from plasmacytoid-lymphocytes by transition, and the latter from the transition of lymphocytes. In addition, relatively a small fraction of cells in these two compartments are formed by proliferation. mature plasma cells do not and immature plasma cells do proliferate. Estimation of magnitude of plasma cells formed in the cultures at day 18 indicated that at least one plasma cell is formed for every 6 normal human blood lymphocytes introduced into the culture

  19. Oxcarbazepine-induced cytotoxicity and genotoxicity in human lymphocyte cultures with or without metabolic activation.

    Science.gov (United States)

    Atlı Şekeroğlu, Zülal; Kefelioğlu, Haluk; Kontaş Yedier, Seval; Şekeroğlu, Vedat; Delmecioğlu, Berrin

    2017-03-01

    There has been considerable debate about the relationship between epilepsy and cancer. Oxcarbazepine (OXC) is used for treating certain types of seizures in patients with epilepsy. There have been no detailed investigations about genotoxicity of OXC and its metabolites. Therefore, the aim of this study is to investigate the cytotoxic and genotoxic effects of OXC and its metabolites on cultured human lymphocytes. The cytotoxicity and genotoxicity of OXC on human peripheral blood lymphocytes were examined in vitro by sister chromatid exchange (SCE), chromosomal aberration (CA) and micronucleus (MN) tests. Cultures were treated with 125, 250 and 500 μg/ml of OXC in the presence (3 h treatment) and absence (24 h and 48 h treatment) of a metabolic activator (S9 mix). Dimethyl sulfoxide (DMSO) was used as a solvent control. OXC showed cytotoxic activities due to significant decreases in mitotic index (MI), proliferation index (PI) and nuclear division index (NDI) in the absence of S9 mix when compared with solvent control. Metabolites of OXC also significantly reduced MI and PI in cultures with S9 mix. OXC significantly increased the CAs, aberrant cells, SCE and MN values in the presence and absence of S9 mix. Our results indicated that both OXC and its metabolites have cytotoxic, cytostatic and genotoxic potential on human peripheral blood lymphocyte cultures under the experimental conditions. Further studies are necessary to elucidate the relationship between cytotoxic, cytostatic and genotoxic effects, and to make a possible risk assessment in patients receiving therapy with this drug.

  20. Biological Dosimetry of In Vitro Irradiation with Radionuclides : Comparison of Whole Blood, Lymphocyte and Buffy Coat Culture

    International Nuclear Information System (INIS)

    Kim, Jong Ho; Lee, Dong Soo; Choi, Chang Woon; Chung, June Key; Lee, Myung Chul; Koh, Chang Soon; Kim, Chong Soon; Kim, Hee Geun; Kang, Duck Won; Song, Myung Jae

    1995-01-01

    The purpose of this study was to establish mononuclear cell cultures such as lymphocytes or buffy coat for the biological dosimetry of in vitro irradiation of the radionuclide Tc-99m in order to exclude the effect of residual doses seen in the cultures of whole blood. Biological dosimetry of Tc-99m on cultured mononuclear cells at doses ranging from 0.05 to 6.00 Gy, by scoring unstable chromosomal aberrations(Ydr) observed in cultured lymphocytes, were performed using peripheral venous blood of healthy normal person. The results showed that; (1) In vitro irradiation of radioisotope in separated lymphocyte or buffy coat showed trace amount af residual doses of isotope after washing. Residual doses of isotopes are increased in proportion tn exposed time and irradiated dose without difference between I-131 anct Tc-99m. (2) We obtained these linear-quadratic dose response equations in lymphocyte and buffy coat culture after in vitro irradiation of Tc-99m, respectively (Ydr = 0,001949 D 2 +0,006279D+ 0.000185; Ydr= 0.002531 D 2 -0.003274 D+0.003488). In conclusion, the linear quadrstic dose response equation from in vitro irradiation of Tc-99m with lymphocyte and buffy coat culture was thought to be useful for assessing Tc-99m indueed biological effects. And mononuclear cell cultures seem to be the most appropriate experimental model for the assessment of biological dosimetry of internal irradiation of radionuclides.

  1. Chromosome dosimetry: the influence of culture media on the proliferation of irradiated and unirradiated human lymphocytes

    International Nuclear Information System (INIS)

    Purrott, R.J.; Lloyd, D.C.; Vulpis, N.

    1981-01-01

    The proliferation of phytohaemagglutinin stimulated human lymphocytes in four types of synthetic culture medium has been studied using the fluorescence plus Giemsa staining technique to determine cell cycle status. 48 hour cultures of unirradiated cells containing Ham's F10 or RPMI 1640 media yielded significant numbers of second cycle metaphases. Cultures containing Eagle's MEM or TC 199 media, however, required longer incubation times to produce appreciable numbers of second division cells. Intrinsic differences between donors in the rate of proliferation had little effect on the relative ranking of the media. Radiation induced mitotic delay of about 1 hour per Gray was observed for each medium. The relevance of these results to the accuracy of radiation dose estimation by chromosome aberration analysis is discussed. (author)

  2. Genotoxic and cytotoxic effects of different types of dental cement on normal cultured human lymphocytes.

    Science.gov (United States)

    Bakopoulou, A; Mourelatos, D; Tsiftsoglou, A S; Giassin, N P; Mioglou, E; Garefis, P

    2009-01-31

    In this study we have investigated the genotoxic and cytotoxic effects of eluates derived from different types of commercially available dental cements, including glass ionomer cements (GICs) (Ketac Cem/3M ESPE and GC Fuji I/GC Corp), resin-modified glass ionomer cements (RM-GICs) (RelyX Luting/3M ESPE and Vitrebond/3M ESPE) and dual-cure resin cements (RCs) (Variolink II/ Ivoclar-Vivadent and Panavia F 2.0/Kuraray) on normal cultured human lymphocytes. Lymphocyte primary cultures obtained from blood samples of three healthy donors were exposed to serial dilutions of eluates derived from specimens of each material tested. Metaphases were induced with phytohaemagglutinin, collected after 72h treatment by use of colchicine and stained according to the fluorescence plus giemsa (FPG) procedure. Preparations were scored for sister chromatid exchange (SCE) and chromosomal aberrations (CAs), while the proliferation rate index (PRI) was also calculated. Our results show that eluates derived from the RM-GICs and RCs caused severe genotoxic effects by significantly increasing the frequencies of SCEs and CAs in cultures of peripheral blood lymphocytes and by decreasing the relevant PRI values in a dose-dependent manner, whereas the two GICs caused only minor cytogenetic effects. Eluates of the two RM-GICs (Vitrebond and RelyX) were also very cytotoxic, as the first serial dilutions of both materials caused a complete mitotic arrest in lymphocyte cultures. Overall, the degree of genotoxicity and cytotoxicity caused by dental cements decreased as follows: Viterbond>Rely X>Panavia F 2.0>Variolink II>Ketac Cem=GC Fuji I. These results indicate that different types of dental cement differ extensively in their genotoxic and cytotoxic potential and their ability to affect chromosomal integrity, cell-cycle progression, DNA replication and repair. Although these results cannot be directly extrapolated to the clinical situation, the potential occurrence of adverse effects caused by the

  3. [Application of a modified culturing method for lymphocytes in cytogenetic research].

    Science.gov (United States)

    Gao, Chaoxian; Hui, Changye; Zhang, Wen; Guo, Yan; Li, Limei; Chen, Yuting; Zhang, Liuzhuo; Yang, Xinyue; Huang, Xianqing

    2016-08-01

    To establish a modified method for microculturing whole human blood for cytogenetic analysis. A novel tube rack was designed to overcome the drawbacks of directly culturing the cells within centrifuge tubes. The fractions of human plasma, human serum and two commercial fetal bovine sera were analyzed with 15% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The influence of adding 0%, 5%, 10%, 15%, 20%, 25% and 30% autologous plasma to the culture on lymphocyte transformation rate and mitotic index (MI) was examined. The SDS-PAGE analysis showed a significant difference between commercial fetal bovine sera, and that the components of human plasma were similar to those of fetal bovine serum. The value of MI in lymphocyte was evidently increased along with addition of autologous plasma. However, this has exerted no significant effect on the transformation rate. With the addition of 10% autologous plasma, the MI value has become much higher than the conventional method. A modified method was established by application of a novel tube inclined rack and optimization of whole blood inoculation. This method is easier and cheaper, and is suitable for application in clinical practice.

  4. Nonrandom distribuion of chromosome breaks in cultured lymphocytes of normal subjects

    Energy Technology Data Exchange (ETDEWEB)

    Ayme, S.; Mattei, J.F.; Mattei, M.G.; Aurran, Y.; Giraud, F.

    1976-02-29

    Breakpoint distribution was studied from cultured lymphocytes on 7653 metaphases from 524 subjects whose karyotypes were normal. The mean break rate was 5% in both sexes. The frequency increased significantly after 40 years and varied during the year. The location of the breaks was very different from the expected random distribution. The break frequency for each chromosome was different according to the type of break (chromatid, simple chromosomal and chromosomal involving rearrangements). The location of the breaks was also studied according to the type of band and with respect to the centromere. A comparison between spontaneous breaks, x-ray induced breaks, breaks in Fanconi's anemia and in congenital rearrangements, show very significant differences.

  5. In Vitro Genotoxic Effects of Four Helichrysum Species in Human Lymphocytes Cultures

    Directory of Open Access Journals (Sweden)

    Erhan H Erolu

    2010-01-01

    Full Text Available Helichrysum sanguineum, Helichrysum pamphylicum, Helichrysum orientale, Helichrysum noeanum (Asteraceae are medicinal plants. For centuries, they have been used as tea in Turkey because of their medicinal properties. So far no scientifc evidence has been found in a literature survey regarding the genotoxic effects of these plants. This work evaluated the genotoxic effects on human lymphocyte cultures induced by methanol extracts of these plants, assayed in different concentrations (0.01, 0.05, 0.1, 0.5 and 1 mg/mL. According to the results, Helichrysum noeanum, Helichrysum pamphylicum and Helichrysum sanguineum induced the formation of micronuclei and decreased the mitotic and replication indexes. Helichrysum orientale did not affect these parameters, whereas Helichrysum noeanum, Helichrysum pamphylicum and Helichrysum sanguineum were clearly genotoxic. They should therefore not be used freely in alternative medicine, although their antiproliferative activity may suggest antimitotic and anticarcinogenic properties. Helichrysum orientale could be used in alternative medicine.

  6. In vitro genotoxic effects of four Helichrysum species in human lymphocytes cultures.

    Science.gov (United States)

    Erolu, Erhan H; Hamzaolu, Ergin; Aksoy, Ahmet; Budak, Ümit; Özkul, Yusuf

    2010-01-01

    Helichrysum sanguineum, Helichrysum pamphylicum, Helichrysum orientale, Helichrysum noeanum (Asteraceae) are medicinal plants. For centuries, they have been used as tea in Turkey because of their medicinal properties. So far no scientific evidence has been found in a literature survey regarding the genotoxic effects of these plants. This work evaluated the genotoxic effects on human lymphocyte cultures induced by methanol extracts of these plants, assayed in different concentrations (0.01, 0.05, 0.1, 0.5 and 1 mg/mL). According to the results, Helichrysum noeanum, Helichrysum pamphylicum and Helichrysum sanguineum induced the formation of micronuclei and decreased the mitotic and replication indexes. Helichrysum orientale did not affect these parameters, whereas Helichrysum noeanum, Helichrysum pamphylicum and Helichrysum sanguineum were clearly genotoxic. They should therefore not be used freely in alternative medicine, although their antiproliferative activity may suggest antimitotic and anticarcinogenic properties. Helichrysum orientale could be used in alternative medicine.

  7. A new gaseous imaging detector for the assay of lymphocyte cultures

    International Nuclear Information System (INIS)

    Bateman, J.E.; Joyce, A.; Knight, S.C.; Bedford, P.

    1991-01-01

    Tritium-labelled cell cultures used in studies of lymphocyte proliferation at the Clinical Research Centre are blotted in arrays of 10x6 spots spaced at 6 mm. An imaging detector based on the differential induction signals produced at a central amplifying electrode has been developed for the imaging and assay of these blots. A spatial resolution ≅ 2.5 mm FWHM attained over the aperture of 60 mmx36mm enables the individual spots to be reliably counted. Data is captured in a PC/AT at rates which permit an assay to be completed in typically 30-60 min. The simplicity of both the detector and the readout electronics leads to a low cost system. Images and assay results are presented. (orig.)

  8. Post-thaw non-cultured and post-thaw cultured equine cord blood mesenchymal stromal cells equally suppress lymphocyte proliferation in vitro.

    Directory of Open Access Journals (Sweden)

    Lynn B Williams

    Full Text Available Multipotent mesenchymal stromal cells (MSC are receiving increased attention for their non-progenitor immunomodulatory potential. Cryopreservation is commonly used for long-term storage of MSC. Post-thaw MSC proliferation is associated with a lag-phase in vitro. How this lag-phase affect MSC immunomodulatory properties is unknown. We hypothesized that in vitro there is no difference in lymphocyte suppression potential between quick-thawed cryopreserved equine cord blood (CB MSC immediately included in mixed lymphocyte reaction (MLR and same MSC allowed post-thaw culture time prior to inclusion in MLR. Cryopreserved CB-MSC from five unrelated foals were compared using two-way MLR. For each of the five unrelated MSC cultures, paired MLR assays of MSC allowed five days of post-thaw culture and MSC included in MLR assay immediately post-thawing were evaluated. We report no difference in the suppression of lymphocyte proliferation by CB-MSC that had undergone post-thaw culture and MSC not cultured post-thaw (p<0.0001. Also, there was no inter-donor variability between the lymphocyte suppressive properties of MSC harvested from the five different donors (p = 0.13. These findings suggest that cryopreserved CB-MSC may have clinical utility immediately upon thawing. One implication hereof is the possibility of using cryopreserved CB-MSC at third party locations without the need for cell culture equipment or competencies.

  9. Radioprotective effect of sesamol on γ-radiation induced DNA damage, lipid peroxidation and antioxidants levels in cultured human lymphocytes

    International Nuclear Information System (INIS)

    Prasad, N. Rajendra; Menon, Venugopal P.; Vasudev, V.; Pugalendi, K.V.

    2005-01-01

    Sesamol pretreated (1, 5 and 10 μg/ml) lymphocytes were exposed to different doses of γ-radiation, i.e., 1, 2 and 4 Gray (Gy) and the cellular changes were estimated by using cytokinesis blocked micronucleus assay (MN), dicentric aberration (DC), thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Radiation significantly increased MN, DC frequencies, TBARS levels and decreased GSH and antioxidant enzyme levels in a dose dependent manner. The highest damage to lymphocytes was observed at 4 Gy irradiation. On the other hand, sesamol pretreatment significantly decreased MN, DC frequencies, TBARS levels and increased GSH levels and SOD, CAT and GPx activities in a concentration dependent manner. At 1 Gy irradiation all concentrations of sesamol (1, 5 and 10 μg/ml) significantly protects the lymphocytes from radiation damage. At 2 Gy irradiation 5 and 10 μg/ml of sesamol shows significant radioprotection. Since the highest damage was observed at 4 Gy irradiation both 1 and 5 μg/ml of sesamol pretreatment were not sufficient to protect the lymphocytes from radiation damage but 10 μg/ml of sesamol significantly (p < 0.05) protects the lymphocytes from radiation effect. Thus, sesamol pretreatment gives significant protection to cultured human lymphocytes against γ-radiation induced cellular damage. The possible mechanism involved in the radioprotective influence of sesamol is discussed

  10. Use of an adaptable cell culture kit for performing lymphocyte and monocyte cell cultures in microgravity

    Science.gov (United States)

    Hatton, J. P.; Lewis, M. L.; Roquefeuil, S. B.; Chaput, D.; Cazenave, J. P.; Schmitt, D. A.

    1998-01-01

    The results of experiments performed in recent years on board facilities such as the Space Shuttle/Spacelab have demonstrated that many cell systems, ranging from simple bacteria to mammalian cells, are sensitive to the microgravity environment, suggesting gravity affects fundamental cellular processes. However, performing well-controlled experiments aboard spacecraft offers unique challenges to the cell biologist. Although systems such as the European 'Biorack' provide generic experiment facilities including an incubator, on-board 1-g reference centrifuge, and contained area for manipulations, the experimenter must still establish a system for performing cell culture experiments that is compatible with the constraints of spaceflight. Two different cell culture kits developed by the French Space Agency, CNES, were recently used to perform a series of experiments during four flights of the 'Biorack' facility aboard the Space Shuttle. The first unit, Generic Cell Activation Kit 1 (GCAK-1), contains six separate culture units per cassette, each consisting of a culture chamber, activator chamber, filtration system (permitting separation of cells from supernatant in-flight), injection port, and supernatant collection chamber. The second unit (GCAK-2) also contains six separate culture units, including a culture, activator, and fixation chambers. Both hardware units permit relatively complex cell culture manipulations without extensive use of spacecraft resources (crew time, volume, mass, power), or the need for excessive safety measures. Possible operations include stimulation of cultures with activators, separation of cells from supernatant, fixation/lysis, manipulation of radiolabelled reagents, and medium exchange. Investigations performed aboard the Space Shuttle in six different experiments used Jurkat, purified T-cells or U937 cells, the results of which are reported separately. We report here the behaviour of Jurkat and U937 cells in the GCAK hardware in ground

  11. The Effect Of SEA On Long Tail Monkeys (Macaca Fascicularis) Lymphocyte Culture Gamma Ray-Irradiated In Vitro

    International Nuclear Information System (INIS)

    Wa'id, Abdul; Lusiyanti, Yanti

    2000-01-01

    Staphylococus enteroxine (SEA) is one of toxins produced by the bacterium Staphylococus aureus. In the culture, SEA has proven as a potent stimulator of lymphocytes in man event at fg/ml concentrations. This research studied the effect of SEA compared to Phytohaemagglutinine (PHA) on the peripheral blood lymphocytes culture of the long-tail monkeys. About 5 ml blood was collected from 5 monkeys and irradiated using Gamma Cell-220 P3TIR with doses of 0 (control); 1.0; 2.0; 3.0 and 4.0 Gy. The blood samples were cultured in the appropriate growth medium based on standard procedure and added with 1.0 ml (0.5 mug/ml) SEA or 0.15 ml PHA. The cultures were then incubated for 96 hours and prepared the slides. The results showed that on the unirradiated peripheral blood lymphocytes of long-tail monkeys the mitotic indices obtained using PHA and SEA are relatively similar. On the irradiated lymphocytes with doses of 1-3 Gy, the mitotic indices using SEA are relatively higher than that of PHA. Dose responses of dicentric, ring and acentric fragment of both PHA and SEA are relatively the same

  12. Sensitivity of cultured lymphocytes from patients with nevoid basal cell carcinoma syndrome to ultraviolet light and phytohemagglutinin stimulation

    International Nuclear Information System (INIS)

    Ferraro, P.; Celotti, L.; Furlan, D.; Pattarello, I.; Peserico, A.

    1990-01-01

    DNA repair and replication after in vitro UV irradiation were determined in cultured peripheral blood lymphocytes from 6 patients with nevoid basal cell carcinoma syndrome (NBCCS) and from a group of control donors. DNA repair synthesis (UDS) was measured in unstimulated lymphocytes by incubation with 3H-TdR in the presence of hydroxyurea for 3 and 6 h after UV irradiation (6-48 J/m2). DNA replication was measured in PHA-stimulated lymphocytes, UV-irradiated or mock-irradiated, by incubation with 3H-TdR for 24 h. The effect of the mitogen was followed during 5 days after stimulation by determining the incorporation of 3H-TdR, the increase of cell number, and the mitotic index. NBCCS and control lymphocytes showed equal sensitivity to UV light in terms of UDS and reduced response to PHA. On the contrary, the mitotic index and the number of cells in stimulated cultures were significantly lower in the affected subjects. These data suggest an altered progression along the cell cycle, which could be characteristic of stimulated NBCCS lymphocytes

  13. Measurement of T-lymphocyte responses in whole-blood cultures using newly synthesized DNA and ATP.

    Science.gov (United States)

    Sottong, P R; Rosebrock, J A; Britz, J A; Kramer, T R

    2000-03-01

    The proliferative response is most frequently determined by estimating the amount of [(3)H]thymidine incorporated into newly synthesized DNA. The [(3)H]thymidine procedure requires the use of radioisotopes as well as lengthy periods of incubation (>72 h). An alternative method of assessing T-lymphocyte activation in whole-blood cultures involves the measurement of the nucleotide ATP instead of [(3)H]thymidine incorporation. In addition, the Luminetics assay of T-cell activation measures specific T-lymphocyte subset responses through the use of paramagnetic particles coated with monoclonal antibodies against CD antigens. This assay permits rapid (24 h) analysis of lymphocyte subset activation responses to mitogens and recall antigens in small amounts of blood.

  14. Segregation of B lymphocytes into stationary apoptotic and migratory proliferating subpopulations in agglomerate cultures with ileal epithelium.

    Science.gov (United States)

    Alitheen, N; McClure, S; McCullagh, P

    2001-09-01

    The B lymphocyte-epithelial cell interactions that define the microenvironment of the ileal Peyer's patch, the primary B lymphocyte organ of the fetal lamb, have been replicated in tissue culture. Mixed suspensions of ileal epithelial cells, lymphocytes and fibroblasts from fetuses of 63-103 days of gestation organized into macroscopically visible agglomerates within 72 h. These agglomerates contained translucent spherical cavities and were enclosed within a marginal cell layer and surrounded by an expanding corona of emigrating cells. The lining of the cavities and the marginal layer consisted of well-differentiated, polarized columnar ileal epithelial cells. One population of B lymphocytes in the initial mixed suspension differentiated into two discrete populations reproducing the characteristics of intact fetal ileal Peyer's patches. B cells apposed to follicle-associated epithelium (FAE) within agglomerates underwent apoptosis. The other population of emigrant B cells proliferated and expressed the BAQ44A differentiation marker. Differentiation of ileal epithelial cells into FAE, typical of Peyer's patches, was markedly accelerated. The mutually inductive influences of intestinal epithelial cells and B lymphocytes in these agglomerates replicate normal mid-gestational fetal development of the mucosal immune system and afford new opportunities for its further investigation.

  15. Intra HLA-D/DR region recombinant detected by primed lymphocyte typing (PLT)

    DEFF Research Database (Denmark)

    Jakobsen, B K; Kristensen, T; Lamm, L U

    1983-01-01

    The chromosome 6 markers, HLA-ABC, D, DR, MT, properdin factor Bf, and complement factors 2 (C2) and 5 (C4), were studied in three families, each of which included two HLA identical siblings, one or both of whom were known to be HLA-B: GLO recombinants. The families were also typed with primed...... lymphocyte typing (PLT) for HLA-D/DR region associated DP antigens. None of these studies gave evidence that the recombinations had occurred within the HLA region. Mixed leucocyte culture (MLC) tests within the families showed no detectable stimulation between the HLA identical siblings in two...

  16. Proliferation of Peripheral Blood Lymphocytes and Mesenchymal Stromal Cells Derived from Wharton's Jelly in Mixed and Membrane-Separated Cultures.

    Science.gov (United States)

    Poltavtsev, A M; Poltavtseva, R A; Yushina, M N; Pavlovich, S V; Svirshchevskaya, E V

    2017-08-01

    We studied the effect of mesenchymal stromal cells on proliferation of CFSE-stained T cells in mixed and membrane-separated (Transwell) cultures and in 3D culture of mesenchymal stromal cells from Wharton's jelly. The interaction of mesenchymal stromal cells with mitogen-activated peripheral blood lymphocytes from an allogeneic donor was followed by suppression of T-cell proliferation in a wide range of cell proportions. Culturing in the Transwell system showed the absence of suppression assessed by the fraction of proliferating cells and by the cell cycle analysis. In 3D cultures, contact interaction of mesenchymal stromal cells and lymphocytes was demonstrated that led to accumulation of G2/M phase lymphocytes and G0/G1 phase mesenchymal stromal cells. The suppressive effect of mesenchymal stromal cells from Wharton's jelly is mediated by two mechanisms. The effects are realized within 6 days, which suggests that the therapeutic effects of mesenchymal stromal cells persist until their complete elimination from the body.

  17. Detection of chromosomal changes in chronic lymphocytic leukemia using classical cytogenetic methods and FISH: application of rich mitogen mixtures for lymphocyte cultures.

    Science.gov (United States)

    Koczkodaj, Dorota; Popek, Sylwia; Zmorzyński, Szymon; Wąsik-Szczepanek, Ewa; Filip, Agata A

    2016-04-01

    One of the research methods of prognostic value in chronic lymphocytic leukemia (CLL) is cytogenetic analysis. This method requires the presence of appropriate B-cell mitogens in cultures in order to obtain a high mitotic index. The aim of our research was to determine the most effective methods of in vitro B-cell stimulation to maximize the number of metaphases from peripheral blood cells of patients with CLL for classical cytogenetic examination, and then to correlate the results with those obtained using fluorescence in situ hybridization (FISH). The study group involved 50 consecutive patients with CLL. Cell cultures were maintained with the basic composition of culture medium and addition of respective stimulators. We used the following stimulators: Pokeweed Mitogen (PWM), 12-O-tetradecanoylphorbol 13-acetate (TPA), ionophore, lipopolysaccharide (LPS), and CpG-oligonucleotide DSP30. We received the highest mitotic index when using the mixture of PWM+TPA+I+DSP30. With classical cytogenetic tests using banding techniques, numerical and structural aberrations of chromosomes were detected in 46 patients, and no change was found in only four patients. Test results clearly confirmed the legitimacy of using cell cultures enriched with the mixture of cell stimulators and combining classical cytogenetic techniques with the FISH technique in later patient diagnosing. Copyright © 2016 American Federation for Medical Research.

  18. Specific proliferative response of human lymphocytes to purified soluble antigens from Plasmodium falciparum in vitro cultures and to antigens from malaria patients' sera

    DEFF Research Database (Denmark)

    Bygbjerg, I C; Jepsen, S; Theander, T G

    1985-01-01

    Antigens of Plasmodium falciparum, in supernatants of in vitro cultures of the parasite were affinity purified on columns prepared with the IgG fraction of the serum of an immune individual. The purified antigens induced proliferation of lymphocytes from persons who had recently had malaria....... The responses were strongest with lymphocytes from individuals infected with falciparum and ovale malaria; vivax malaria infections induced a lower level of response and lymphocytes of unsensitized individuals were little affected. Lymphocytes from unsensitized individuals did not respond to the affinity...

  19. microRNA expression profiles in human peripheral blood lymphocytes cultured in modeled microgravity

    Data.gov (United States)

    National Aeronautics and Space Administration — In the present study we analyzed miRNA and mRNA expression profiles in human peripheral blood lymphocytes (PBLs) incubated in microgravity condition simulated by a...

  20. Gene expression profiling of human peripheral blood lymphocytes cultured in modeled microgravity

    Data.gov (United States)

    National Aeronautics and Space Administration — In the present study we analyzed miRNA and mRNA expression profiles in human peripheral blood lymphocytes (PBLs) incubated in microgravity condition simulated by a...

  1. In vitro culture of skin-homing T lymphocytes from inflammatory skin diseases

    DEFF Research Database (Denmark)

    Bang, Karen; Lund, Marianne; Mogensen, Søren C

    2005-01-01

    We, in this study, describe how T lymphocytes in a skin biopsy can proliferate in vitro for up to 3 months by using T-cell growth factors - interleukin-2 (IL-2) and IL-4 yielding approximately 100-160 million T lymphocytes within 1 month. We established cell lines from three tuberculin skin tests......, four positive patch tests, 15 of 16 biopsies from atopic dermatitis (AD), 15 of 19 biopsies from mycosis fungoides (MF), 12 of 24 biopsies from psoriasis vulgaris, which was significantly less than AD (P lymphocytes (P ... to immediate halt of proliferation. Blood mononuclear cells from patients and biopsies from healthy persons never gave cell lines. All cells were T lymphocytes expressing CD45RO+, HLA-DR+ and CD150. The CD7 expression was significantly increased in cell lines from AD (P

  2. Induction and persistence of multicentric chromosomes in cultured human peripheral blood lymphocytes following high-dose gamma irradiation

    International Nuclear Information System (INIS)

    Suto, Yumiko; Hirai, Momoki; Akiyama, Miho; Nakagawa, Takashi; Tominaga, Takako; Suzuki, Toshikazu; Sugiura, Nobuyuki; Yuki, Masanori; Nakayama, Fumiaki

    2012-01-01

    Among radiation-induced chromosome aberrations, multicentric chromosomes, as represented by dicentric chromosomes (dicentrics), are regarded as sensitive and specific biomarkers for assessing radiation dose in the 0 to 5 Gy range. The objective of this study was to characterize chromosome aberrations induced in vitro by a higher dose of radiation. Peripheral blood lymphocytes were exposed to 15 Gy gamma rays at a dose rate of 0.5 Gy/min and harvested at 48, 50, 52, 54, 56 and 72 h. The first mitotic peak appeared at 52-54 h, showing about a 6 h mitotic delay as compared with nonirradiated control cultures. Cell-cycle analysis of parallel and simultaneous cultures by sister-chromatid differentiation staining suggests that metaphase cells examined in 48-56 h cultures were in the first mitosis after culture initiation. The mean dicentric equivalent counts ranged from 9.0 to 9.3 in consecutively harvested cultures with no significant differences among them. At 72 h, about 20% of dividing cells were tetraploid, persisting with faithfully replicated unstable chromosome aberrations. The non-random distribution of replicated chromosome pairs, deduced from multicolor fluorescence in situ hybridization analysis, led us to surmise that the predominant mechanism underlying the induction of tetraploid cells is endoreduplication. These findings suggest that a high-dose in vitro irradiation applied to peripheral blood lymphocytes may affect on the replication process, in addition to structural chromosome damage. (author)

  3. Activation of NK Cells in Mixed Cultures of Wharton's Jelly Mesenchymal Stromal Cells and Peripheral Blood Lymphocytes.

    Science.gov (United States)

    Svirshchevskaya, E V; Poltavtsev, A M; Os'mak, G Zh; Poltavtseva, R A

    2018-01-01

    Mesenchymal stromal cells possess immunosuppressive properties that might be used for the therapy of inflammatory diseases of various geneses. The effects of mesenchymal stromal cells depend on their lifetime in the recipient tissues. During heterologous transplantation, mesenchymal stromal cells are eliminated by NK cells. We studied NK cell formation in mixed cultures of Wharton's jelly mesenchymal stromal cells and peripheral blood lymphocytes from an autologous donor. Lymphocytes were activated by a mitogen or IL-2. The lifetime of mesenchymal stromal cells was estimated by MTT test. Cytotoxic activity and phenotype of NK cells were evaluated by flow cytometry. It was found that activation of NK cells depended on IL-2 and was registered on day 2 of incubation with IL-2. In cultures with mitogen-activated lymphocytes, cytotoxicity was observed after 5-6 days. Cytotoxicity of NK correlated with significant decrease in CD16+ and increase in CD56+ NK and with reduction of mesenchymal stromal cell viability. Thus, the main mechanism of elimination of mesenchymal stromal cells is cytotoxicity of NK cells that depended on IL-2 production.

  4. DEPTOR-mTOR Signaling Is Critical for Lipid Metabolism and Inflammation Homeostasis of Lymphocytes in Human PBMC Culture

    Directory of Open Access Journals (Sweden)

    Qi-bing Xie

    2017-01-01

    Full Text Available Abnormal immune response of the body against substances and tissues causes autoimmune diseases, such as polymyositis, dermatomyositis, and rheumatoid arthritis. Irregular lipid metabolism and inflammation may be a significant cause of autoimmune diseases. Although much progress has been made, mechanisms of initiation and proceeding of metabolic and inflammatory regulation in autoimmune disease have not been well-defined. And novel markers for the detection and therapy of autoimmune disease are urgent. mTOR signaling is a central regulator of extracellular metabolic and inflammatory processes, while DEP domain-containing mTOR-interacting protein (DEPTOR is a natural inhibitor of mTOR. Here, we report that overexpression of DEPTOR reduces mTORC1 activity in lymphocytes of human peripheral blood mononuclear cells (PBMCs. Combination of DEPTOR overexpression and mTORC2/AKT inhibitors effectively inhibits lipogenesis and inflammation in lymphocytes of PBMC culture. Moreover, DEPTOR knockdown activates mTORC1 and increases lipogenesis and inflammations. Our findings provide a deep insight into the relationship between lipid metabolism and inflammations via DEPTOR-mTOR pathway and imply that DEPTOR-mTOR in lymphocytes of PBMC culture has the potential to be as biomarkers for the detection and therapies of autoimmune diseases.

  5. Human thiopurine methyltransferase pharmacogenetics: effect of phenotype on sensitivity of cultured lymphocytes to 6-mercaptopurine

    International Nuclear Information System (INIS)

    Van Loon, J.; Weinshilboum, R.

    1986-01-01

    Thiopurine methyltransferase (EC 2.1.1.67, TPMT) catalyzes the S-methylation of thiopurine drugs such as 6-mercaptopurine (6-MP). TPMT activity in human lymphocytes and other tissues is controlled by a common genetic polymorphism. These experiments were designed to study the relationship between TPMT phenotype and the effect of 6-MP on 3 H-thymidine ( 3 H-TdR) incorporation into phytohemaglutinin (PHA) stimulated human peripheral blood lymphocytes. Lymphocytes were obtained from the blood of nine subjects, three subjects with each TPMT phenotype. 6-MP dose response curves were performed at optimal (10 μg/ml) and suboptimal (1 μg/ml) concentrations of PHA. ED50 values for 6-MP with lymphocytes from subjects who genetically lacked TPMT activity were higher than ED50 values for lymphocytes from subjects with genetically intermediate or high TPMT activity. However, ED50 values decreased as level of stimulation increased. Therefore, the effects of 6-MP were studied at a series of PHA concentrations that ranged from 0.1 μg/ml to 10 μg/ml. Lymphocytes from subjects who lacked TPMT activity had significantly higher K/sub ii/ values (1.37 +/- 0.340 μM; mean +/- SEM) for inhibition of 3 H-TdR incorporation by 6-MP than did lymphocytes from subjects with intermediate or high TPMT activity (0.529 +/- 0.068 μM and 0.327 +/- 0.064 μM, respectively, P < .05 for both comparisons)

  6. Human thiopurine methyltransferase pharmacogenetics: effect of phenotype on sensitivity of cultured lymphocytes to 6-mercaptopurine

    Energy Technology Data Exchange (ETDEWEB)

    Van Loon, J.; Weinshilboum, R.

    1986-03-05

    Thiopurine methyltransferase (EC 2.1.1.67, TPMT) catalyzes the S-methylation of thiopurine drugs such as 6-mercaptopurine (6-MP). TPMT activity in human lymphocytes and other tissues is controlled by a common genetic polymorphism. These experiments were designed to study the relationship between TPMT phenotype and the effect of 6-MP on /sup 3/H-thymidine (/sup 3/H-TdR) incorporation into phytohemaglutinin (PHA) stimulated human peripheral blood lymphocytes. Lymphocytes were obtained from the blood of nine subjects, three subjects with each TPMT phenotype. 6-MP dose response curves were performed at optimal (10 ..mu..g/ml) and suboptimal (1 ..mu..g/ml) concentrations of PHA. ED50 values for 6-MP with lymphocytes from subjects who genetically lacked TPMT activity were higher than ED50 values for lymphocytes from subjects with genetically intermediate or high TPMT activity. However, ED50 values decreased as level of stimulation increased. Therefore, the effects of 6-MP were studied at a series of PHA concentrations that ranged from 0.1 ..mu..g/ml to 10 ..mu..g/ml. Lymphocytes from subjects who lacked TPMT activity had significantly higher K/sub ii/ values (1.37 +/- 0.340 ..mu..M; mean +/- SEM) for inhibition of /sup 3/H-TdR incorporation by 6-MP than did lymphocytes from subjects with intermediate or high TPMT activity (0.529 +/- 0.068 ..mu..M and 0.327 +/- 0.064 ..mu..M, respectively, P < .05 for both comparisons).

  7. Human cord blood suppressor T lymphocytes. II. Characterization of inducer of suppressor cells

    International Nuclear Information System (INIS)

    Cheng, H.; Delespesse, G.

    1986-01-01

    Previously, we reported an antigen nonspecific inducer of T suppressor cell factor (TisF) produced by cord blood mononuclear cells (MNC) in 48-hr, two-way mixed lymphocyte cultures (MLC). The target of this factor was a radiosensitive, T4+ (T8-) adult suppressor T cell subset. The cellular origin of this TisF was examined in the present study. IgG production by pokeweed mitogen (PWM)-stimulated adult MNC was used as an assay for TisF activity. It was found that TisF-producing cells formed rosettes with sheep erythrocytes (E+) and were independent of adherent cells (AC) in the production of TisF. They were resistant to irradiation (2500 rads) and phenotypic characterization with T cell reactive monoclonal antibodies indicated that they resided in the T8- (T4+) population. Furthermore, both TQ1- and TQ1+ cells were required for the production of TisF activity and such activity could not be reconstituted by supernatants from TQ1- MLC and TQ1+ MLC. These results indicate that the production of TisF is dependent upon interactions between radioresistant E+, T8-, TQ1- and radioresistant E+, T8-, TQ1+ cells

  8. [Cytogenetic effect of cyclophosphamide in a culture of human lymphocytes following its activation in the bodies of mice].

    Science.gov (United States)

    Chebotarev, A N; Telegin, L I; Derzhavets, E M

    1976-01-01

    Cytogenetic effect of cyclophosphamide in cultured human lymphocytes after its activation in C57BL/6 mice in vivo was investigated. Cyclophosphamide was injected intraperitoneally in mice for 30 min. at doses of 200, 400, 600, 800 and 1000 mg/kg. Blood serum with activated metabolites of cyclophosphamide was added to human lymphocyte culture. The dependence of the part of aberrant metaphases on the concentration of cyclophosphamide after the activation can be presented as equation rho==1-e-(KC+alpha)2 and the total number of breaks as X=e(KC+alpha)2-1, where rho is a part of aberrant metaphases, X is a number of breaks of chromosomes per cell, C is the concentration, K and alpha are coefficients. The part of chromatid breaks from the total number of chromosome damages is constant for all concentrations and the comprises on the average 79,11%. Only the chromatid type of exchanges are observed. Distribution of chromosome breaks in cells corresponds to geometrical, but not to Poisson's distribution. Cyclophosphamide belongs to the group of one-sited mutagens in its cytogenetic chatacteristics. The alkylating activity of cyclophosphamide metabolites, estimated by means of NBP test, increases up to the dose 400 mg/kg and then remains constant for the strain of mice studied, cytogenetic activity increasing. Cyclophosphamide does not produce cytogenetic activity without activation. To test chemical substances for mutagenic activity, it is suggested to activate them in the mouse organism with the following administrating blood serum of these animals with the metabolites of tested (or with primary) substances in the study of their mutagenic activity on human lymphocyte culture.

  9. Dimethyl Sulfoxide (DMSO) Decreases Cell Proliferation and TNF-α, IFN-γ, and IL-2 Cytokines Production in Cultures of Peripheral Blood Lymphocytes.

    Science.gov (United States)

    de Abreu Costa, Lucas; Henrique Fernandes Ottoni, Marcelo; Dos Santos, Michaelle Geralda; Meireles, Agnes Batista; Gomes de Almeida, Valéria; de Fátima Pereira, Wagner; Alves de Avelar-Freitas, Bethânia; Eustáquio Alvim Brito-Melo, Gustavo

    2017-11-10

    Dimethylsulfoxide (DMSO) is an amphipathic molecule composed of a polar domain characterized by the sulfinyl and two nonpolar methyl groups, for this reason it is able to solubilize polar and nonpolar substances and transpose hydrophobic barriers. DMSO is widely used to solubilize drugs of therapeutic applications and studies indicated that 10% v/v concentration did not modify culture viability when used to treat human peripheral blood mononuclear cells (PBMC). However, some DMSO concentrations could influence lymphocyte activation and present anti-inflammatory effects. Therefore, the objective of this study was to evaluate the effect of DMSO on lymphocyte activation parameters. Cell viability analysis, proliferation, and cytokine production were performed on PBMC from six healthy subjects by flow cytometry. The results indicated that 2.5% v/v DMSO concentrations did not modify lymphocytes viability. DMSO at 1% and 2% v/v concentrations reduced the relative proliferation index of lymphocytes and at 5% and 10% v/v concentrations reduced the percentage of total lymphocytes, cluster of differentiation 4⁺ (CD4⁺) T lymphocytes and CD8⁺ T lymphocytes interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2) producers. Thus, it was concluded that DMSO has an in vitro anti-inflammatory effect by reducing lymphocyte activation demonstrated with proliferation reduction and the decrease of cytokine production.

  10. Intra HLA-D/DR region recombinant detected by primed lymphocyte typing (PLT)

    DEFF Research Database (Denmark)

    Jakobsen, B K; Kristensen, T; Lamm, L U

    1983-01-01

    lymphocyte typing (PLT) for HLA-D/DR region associated DP antigens. None of these studies gave evidence that the recombinations had occurred within the HLA region. Mixed leucocyte culture (MLC) tests within the families showed no detectable stimulation between the HLA identical siblings in two......The chromosome 6 markers, HLA-ABC, D, DR, MT, properdin factor Bf, and complement factors 2 (C2) and 5 (C4), were studied in three families, each of which included two HLA identical siblings, one or both of whom were known to be HLA-B: GLO recombinants. The families were also typed with primed...... to reactive reagents. One of these (GHx), reacted with a determinant which segregated within the GG family as if child G was a paternal recombinant between the HLA-D, DR, DP, and C4 loci, on the one hand, and on the other hand one or more loci governing other HLA-D/DR region controlled lymphocyte activating...

  11. Impairment of lymphocyte adhesion to cultured fibroblasts and endothelial cells by γ-irradiation

    International Nuclear Information System (INIS)

    Piela-Smith, T.H.; Aneiro, L.; Nuveen, E.; Korn, J.H.; Aune, T.

    1992-01-01

    A critical component of immune responsiveness is the localization of effector cells at sites of inflammatory lesions. Adhesive molecules that may play a role in this process have been described on the surfaces of both lymphocytes and connective tissue cells. Adhesive interactions of T lymphocytes with fibroblasts or endothelial cells can be inhibited by preincubation of the fibroblasts or endothelial cells with antibody to intercellular adhesion molecule 1 (CD54) or by preincubation of the T cells with antibody to lymphocyte function-associated Ag 1 (CD11a/CD18), molecules shown to be important in several other cell-cell adhesion interactions. Here the authors show that γ-irradiation of human T lymphocytes impaired their ability to adhere to both fibroblasts and endothelial cells. This impairment was not associated with a loss of cell viability or of cell surface lymphocyte function-associated Ag 1 expression. γ-Irradiation of T cells is known to result in the activation of ADP-ribosyltransferase, an enzyme involved in DNA strand-break repair, causing subsequent depletion of cellular nicotinamide adenine dinucleotide (NAD) pools by increasing NAD consumption for poly(ADP-ribose) formation. Preincubation of T cells with either nicotinamide or 3-aminobenzamide, both known inhibitors of ADP-ribosyltransferase, completely reversed the suppressive effects of γ-irradiation on T cell adhesion. The maintenance of adhesion was accompanied by inhibition of irradiation-induced depletion of cellular NAD. These experiments suggest that the impairment of cellular immune function after irradiation in vivo may be caused, in part, by defective T cell emigration and localization at inflammatory sites. 44 refs., 5 figs., 3 tabs

  12. Frequency of sister chromatid exchanges in lymphocyte cultures of human peripheral blood after the combined effect of γ-radiation and caffeine

    International Nuclear Information System (INIS)

    Nugis, V.Yu.; Pyatkin, E.K.

    1986-01-01

    Keeping of human peripheral blood lymphocytes, irradiated in vitro with 60 Co-γ-quanta at a dose of 3 Gy at G 0 phase, with caffeine of 16 and 160 μg/ml during cultivation with PHA had no appreciable influence on the fraquency of sister chromatid exchanges. A minor increase in the number of sister chromatid exchanges was only noted when nonirradiated and irradiated lymphocytes were cultured with 160 μg/ml caffeine

  13. Astaxanthin, a Carotenoid, Stimulates Immune Responses by Enhancing IFN-γ and IL-2 Secretion in Primary Cultured Lymphocytes in Vitro and ex Vivo

    Science.gov (United States)

    Lin, Kuan-Hung; Lin, Kao-Chang; Lu, Wan-Jung; Thomas, Philip-Aloysius; Jayakumar, Thanasekaran; Sheu, Joen-Rong

    2015-01-01

    Astaxanthin, a potent antioxidant carotenoid, plays a major role in modulating the immune response. In this study, we examined the immunomodulatory effects of astaxanthin on cytokine production in primary cultured lymphocytes both in vitro and ex vivo. Direct administration of astaxanthin (70–300 nM) did not produce cytotoxicity in lipopolysaccharide (LPS, 100 µg/ mL)- or concanavalin A (Con A, 10 µg/ mL)-activated lymphocytes, whereas astaxanthin alone at 300 nM induced proliferation of splenic lymphocytes (p < 0.05) in vitro. Although astaxanthin, alone or with Con A, had no apparent effect on interferon (INF-γ) and interleukin (IL-2) production in primary cultured lymphocytes, it enhanced LPS-induced INF-γ production. In an ex vivo experiment, oral administration of astaxanthin (0.28, 1.4 and 7 mg/kg/day) for 14 days did not cause alterations in the body or spleen weights of mice and also was not toxic to lymphocyte cells derived from the mice. Moreover, treatment with astaxanthin significantly increased LPS-induced lymphocyte proliferation ex vivo but not Con A-stimulated lymphocyte proliferation ex vivo. Enzyme linked immunosorbent assay (ELISA) analysis revealed that administration of astaxanthin significantly enhanced INF-γ production in response to both LPS and Con A stimulation, whereas IL-2 production increased only in response to Con A stimulation. Also, astaxanthin treatment alone significantly increased IL-2 production in lymphocytes derived from mice, but did not significantly change production of INF-γ. These findings suggest that astaxanthin modulates lymphocytic immune responses in vitro, and that it partly exerts its ex vivo immunomodulatory effects by increasing INF-γ and IL-2 production without inducing cytotoxicity. PMID:26729100

  14. Induction and prevention of micronuclei and chromosomal aberrations in cultured human lymphocytes exposed to the light of halogen tungsten lamps.

    Science.gov (United States)

    D'Agostini, F; Caimo, A; De Filippi, S; De Flora, S

    1999-07-01

    Previous studies have shown that the light emitted by halogen tungsten lamps contains UV radiation in the UV-A, UV-B and UV-C regions, induces mutations and irreparable DNA damage in bacteria, enhances the frequency of micronuclei in cultured human lymphocytes and is potently carcinogenic to the skin of hairless mice. The present study showed that the light emitted by an uncovered, traditional halogen lamp induces a significant, dose-related and time-related increase not only in micronuclei but also in chromosome-type aberrations, such as breaks, and even more in chromatid-type aberrations, such as isochromatid breaks, exchanges and isochromatid/chromatid interchanges, all including gaps or not, in cultured human lymphocytes. All these genotoxic effects were completely prevented by shielding the same lamp with a silica glass cover, blocking UV radiation. A new model of halogen lamp, having the quartz bulb treated in order to reduce the output of UV radiation, was considerably less genotoxic than the uncovered halogen lamp, yet induction of chromosomal alterations was observed at high illuminance levels.

  15. An alternative approach to studying the effects of ZnO nanoparticles in cultured human lymphocytes: combining electrochemistry and genotoxicity tests.

    Science.gov (United States)

    Branica, Gina; Mladinić, Marin; Omanović, Dario; Želježić, Davor

    2016-12-01

    Nanoparticle use has increased radically raising concern about possible adverse effects in humans. Zinc oxide nanoparticles (ZnO NPs) are among the most common nanomaterials in consumer and medical products. Several studies indicate problems with their safe use. The aim of our study was to see at which levels ZnO NPs start to produce adverse cytogenetic effects in human lymphocytes as an early attempt toward establishing safety limits for ZnO NP exposure in humans. We assessed the genotoxic effects of low ZnO NP concentrations (1.0, 2.5, 5, and 7.5 μg mL-1) in lymphocyte cultures over 14 days of exposure. We also tested whether low and high-density lymphocytes differed in their ability to accumulate ZnO NPs in these experimental conditions. Primary DNA damage (measured with the alkaline comet assay) increased with nanoparticle concentration in unseparated and high density lymphocytes. The same happened with the fragmentation of TP53 (measured with the comet-FISH). Nanoparticle accumulation was significant only with the two highest concentrations, regardless of lymphocyte density. High-density lymphocytes had significantly more intracellular Zn2+ than light-density ones. Our results suggest that exposure to ZnO NPs in concentrations above 5 μg mL-1 increases cytogenetic damage and intracellular Zn2+ levels in lymphocytes.

  16. Optimisation of the CT h4S bioassay for detection of human interleukin-4 secreted by mononuclear cells stimulated by phytohaemaglutinin or by human leukocyte antigen mismatched mixed lymphocyte culture

    DEFF Research Database (Denmark)

    Petersen, Søren Lykke; Russell, Charlotte Astrid; Bendtzen, Klaus

    2002-01-01

    S bioassay detects 5 pg/ml of human recombinant IL-4 with no detection of IL-2 in concentrations below 500 pg/ml. We have found 72 h of culture optimal for detection of IL-2 and IL-4 produced by human mononuclear cells (MNC) in response to stimulation with phytohaemaglutinin and for detection of IL......-2 in human leukocyte antigen (HLA)-mismatched mixed leukocyte culture (MLC). An interindividual variation in cytokine accumulation was demonstrated for IL-4 but not for IL-2. With the use of 5x10(4) responder cells/well no IL-4 could be detected in HLA-mismatched MLC between days 1 and 16. The lack...

  17. In-Vitro Radio protective Role of Ferulic Acid in Cultured Lymphocytes

    International Nuclear Information System (INIS)

    Ahmed, M.M.; Al Fateh, N.M.; Tawfik, S.S.

    2010-01-01

    Ferulic acid (FA), C 10 H 10 O 4 is the most abundant, ubiquitous hydroxycinnamic acid derived from photochemical phenolic compounds. It is a major constituent of fruits and vegetables such as orange, tomato, carrot, sweet corn and rice bran. Gamma rays generate hydroxyl radicals in cells and cellular DNA damage which leads to genotoxicity and chromosome aberrations. To establish most effective protective support, we used two different concentrations of FA (5 and 10 μg/ ml) and 2 Gy dose of gamma-radiation. Cytogenetic analysis was evaluated using the analysis of structural chromosome aberration (CA) and cytokinesis block micronucleus assay (CBMN). The level of lipid peroxidation analyzed as thiobarbituric acid reactive substances (TBARS), total glutathione (GSH), the enzyme activities of lymphocytes defence mechanism: Superoxide dismutase (SOD), Catalase (CAT) and Glutathione peroxidase (GPx) were determined. The result obtained by all endpoints indicates acceptable toxicity profiles of FA in-vitro when compared with normal lymphocytes; irradiation at 2 Gy increased the MN and CA frequencies. Treatment with FA for 30 min before radiation exposure resulted in a significant decline both of MN and CA yields as FA concentration increased. The levels of TBARS and GSH were altered significantly whereas the levels of the enzymatic antioxidants were decreased in gamma-irradiated lymphocytes. Pretreatment with 10 μg/ ml of FA has attenuated the toxic effects of radiation more than FA (5 μg/ ml) by reduction in the TBARS level, restoration GSH contents and prevented the decreases in the radiation-induced SOD, CAT and GPx activities. These results lead us to the conclusion that FA has antimutagenic effect and benefit as a radio protector against oxidative stress involved by gamma-rays exposure

  18. Increased susceptibility to in vitro ultraviolet B radiation in fibroblasts and lymphocytes cultured from systemic lupus erythematosus patients

    International Nuclear Information System (INIS)

    Golan, T.D.; Foltyn, V.; Roueff, A.

    1991-01-01

    Sunlight is known to induce exacerbations of systemic lupus erythematosus (SLE) but its mechanism remains unclear. We have previously reported that ultraviolet A (UVA) exposure induces an increase in total DNA synthesis (DS) in vitro but a decrease in unscheduled DNA repair synthesis (UDRS) of splenocytes of murine SLE strains. In order to investigate whether similar observations are characteristic of human SLE, peripheral blood lymphocytes (PBL) and dermal fibroblast (DF) cultures of 20 patients and 15 matched controls were exposed in vitro to UVA or UVB at different doses. Thirteen (65%) SLE DF cultures exposed to UVB light (12-24 J/m2) showed an increase in DS compared to paired unirradiated cultures. In contrast, UVB-irradiated DF from normal individuals had no significant increase in DS following UVB irradiation. When SLE DF were exposed to higher doses of UVB (48-96 J/m2), 90% of cultures showed a decrease in DS compared to only 20% in the control group. All of the SLE DF cultures showed a decrease of their unscheduled DNA repair capacity following UVB (24-48 J/m2) irradiation whereas no UDRS was apparent in 74% of controls under the same conditions. Similar findings regarding UDRS were observed in SLE PBL cultures and were also confirmed by autoradiography. UVA exposure (0-3840 J/m2) had no effect on DS nor on UDRS in DF or PBL cultured from SLE and controls. The relevance of these in vitro findings to the in vivo pathogenesis of the disease is discussed

  19. Tolerances on MLC leaf position accuracy for IMRT delivery with a dynamic MLC

    International Nuclear Information System (INIS)

    Rangel, Alejandra; Dunscombe, Peter

    2009-01-01

    The objective determination of performance standards for radiation therapy equipment requires, ideally, establishing the quantitative relationship between performance deviations and clinical outcome or some acceptable surrogate. In this simulation study the authors analyzed the dosimetric impact of random (leaf by leaf) and systematic (entire leaf bank) errors in the position of the MLC leaves on seven clinical prostate and seven clinical head and neck IMRT plans delivered using a dynamic MLC. In-house software was developed to incorporate normally distributed errors of up to ±2 mm in individual leaf position or systematic errors (±1 and ±0.5 mm in all leaves of both leaf banks or +1 mm in one bank only) into the 14 plans, thus simulating treatment delivery using a suboptimally performing MLC. The dosimetric consequences of suboptimal MLC performance were quantified using the equivalent uniform doses (EUDs) of the clinical target volumes and important organs at risk (OARs). The deviation of the EUDs of the selected structures as the performance of the MLC deteriorated was used as the objective surrogate of clinical outcome. Random errors of 2 mm resulted in negligible changes for all structures of interest in both sites. In contrast, systematic errors can lead to potentially significant dosimetric changes that may compromise clinical outcome. If a 2% change in EUD of the target and 2 Gy for the OARs were adopted as acceptable levels of deviation in dose due to MLC effects alone, then systematic errors in leaf position will need to be limited to 0.3 mm. This study provides guidance, based on a dosimetric surrogate of clinical outcome, for the development of one component, leaf position accuracy of performance standards for multileaf collimators.

  20. Frequency analysis of cytotoxic T lymphocyte precursors in search for donors in bone marrow transplantation

    International Nuclear Information System (INIS)

    Cukrova, V.; Dolezalova, L.; Loudova, M.; Matejkova, E.; Korinkova, P.; Lukasova, M.; Stary, J.

    1995-01-01

    The usefulness of cytotoxic T lymphocytes (CTLp) frequency analysis in the search for donors in bone marrow transplantation was studied. The frequency of anti-recipient CTLp was approached by limiting dilution assay in HLA matched unrelated, HLA partially matched related and HLA genotypically identical donors. The majority of patients examined were affected with different hematological malignancies. Allo-reactive CTLp recognizing non-HLA gene products were not detected in pre-transplant examination of two pairs of HLA identical siblings. However, an increase incidence of allo-specific CTLp was identified in HLA matched mixed lymphocyte culture (MLC) negative unrelated pairs. Thus, CTLp assay allowed to the residual Class I incompatibilities that remained hidden in standard serotyping. In two matched unrelated pairs with high pretranslant CTLp frequency the severe acute graft-versus-host diseases developed after bone marrow transplantation. Examination of other relatives in patients lacking an HLA identical sibling showed the importance of Class I incompatibility for CTLp generation as well. The lack of correlation between CTLp frequency and HLA-D disparity could suggest that Class II antigens do not participate in CTLp induction. With one exception we had good correlation between MLC and DNA analysis of Class II antigens demonstrating that MLC gives interpretable results even in unrelated pairs. Our results demonstrate the significance of CTLp frequency assay in detection of residual Class I incompatibilities in matched unrelated pairs and in assessment of Class I compatibility in related pairs. For that it should be used in the final selection of bone marrow transplantation donors. (author)

  1. Genotoxic, radioprotective and radiosensitizing effect of curcumin and trans-resveratrol in vitro cultures of human lymphocytes

    International Nuclear Information System (INIS)

    Fisher, V.A.; Tirsa Muñoz, B.; Sebastià, N.; Gómez-Cabrero, L.; La Parra, V.; Hervás, D.; Rodrigo, R.; Villaescusa, J.I.; Soriano, J.M.; Montoro, A.

    2015-01-01

    Curcumin and trans-resveratrol are natural polyphenol compounds. Curcumin is obtained from the rhizomes of the Curcumin plant (Curcuma longa), while trans-resveratrol is found in grapes, blackberries and other types of berry. These compounds have antioxidant, anti-inflammatory, immunostimulant and anticarcinogenic properties among others. In addition, they are also known for their radiomodulating properties since they are capable of providing radioprotection or radiosensitization for normal or tumours cells depending on different factors. This dual action may be the result of their properties, such as free radicals scavenging, as well as their influence on cell cycle checkpoints or control mechanisms. These are activated in response to the genetic damage induced by radiation. Despite the many beneficial properties attributed to these polyphenol compounds, some studies suggest that they are able to be genotoxic agents for some cellular lines. The results obtained indicate that both compounds possess a radioprotective effect on the lymphocytes of peripheral blood in the quiescent phase of the cellular cycle (G0). Nevertheless, they are capable of induce radiosensitivity on these type of cells in the growth phase (G2), and in addition, a different genotoxic effect can be seen according to the concentration of each compound. This study suggests, therefore, that curcumin and trans-resveratrol are able to exert a triple effect, genotoxic, radioprotective and radiosensitizing on in vitro cultures of human lymphocytes depending on the study parameters. [es

  2. Gene expression and inducibility of the aryl hydrocarbon receptor-dependent pathway in cultured bovine blood lymphocytes.

    Science.gov (United States)

    Girolami, Flavia; Spalenza, Veronica; Carletti, Monica; Perona, Giovanni; Sacchi, Paola; Rasero, Roberto; Nebbia, Carlo

    2011-10-10

    The exposure to dioxin-like (DL) compounds, an important class of persistent environmental pollutants, results in the altered expression of target genes. This occurs through the binding to the aryl hydrocarbon receptor (AhR), the subsequent dimerization with the AhR nuclear translocator (ARNT), and the binding of the complex to DNA responsive elements. A number of genes are up-regulated, including, among others, the AhR repressor (AHRR) and several biotransformation enzymes, such as the members of CYP1 family and NAD(P)H-quinone oxidoreductase (NOQ1). The expression and the inducibility of the above genes were investigated in mitogen-stimulated cultured blood lymphocytes from cattle, which represent a notable source of DL-compound human exposure through dairy products and meat. As assessed by real-time PCR, all the examined genes except CYP1A2 and NQO1 were detected under basal conditions. Cell exposure to the DL-compounds PCB126 or PCB77 in the 10(-6)-10(-9)M concentration range resulted in a 2-4-fold induction of CYPIA1 and CYP1B1, which was antagonized by α-naphthoflavone or PCB153. This study demonstrates for the first time the presence and inducibility of the AhR pathway in easily accessible cells like bovine peripheral lymphocytes and prompts further investigations to verify whether similar changes could occur under in vivo conditions. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  3. Lycopene: An antioxidant and radioprotector against γ-radiation-induced cellular damages in cultured human lymphocytes

    International Nuclear Information System (INIS)

    Srinivasan, M.; Devipriya, N.; Kalpana, K.B.; Menon, Venugopal P.

    2009-01-01

    The present study aimed to evaluate the radioprotective effect of lycopene, a naturally occurring dietary carotenoid on γ-radiation-induced toxicity. The cellular changes were estimated by using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS), hydroperoxides (HP), the antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH). The DNA damage was analyzed by cytokinesis blocked micronucleus assay (CBMN), dicentric aberration (DC) and translocation frequency. The γ-radiation at different doses (1, 2 and 4 Gy) resulted in a significant increase in the number of micronuclei (MN), DC, translocation frequency, TBARS and HP level, whereas the levels of GSH and antioxidant enzymes were significantly decreased when compared with normal control. The maximum damage to lymphocytes was observed at 4 Gy irradiation. Lycopene pretreatment (1, 5 and 10 μg/ml) significantly decreased the frequency of MN, DC and translocation when compared with γ-radiation control. The levels of TBARS, HP were also decreased and activities of SOD, CAT and GPx were significantly increased along with GSH levels when compared with γ-radiation control. The dose of 5 μg/ml of lycopene was found to be more effective than the other two doses. Thus, our result shows that pretreatment with lycopene offers protection to normal lymphocytes against γ-radiation-induced cellular damage.

  4. Influence of exogenous leptin on redox homeostasis in neutrophils and lymphocytes cultured in synovial fluid isolated from patients with rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Michał Gajewski

    2016-07-01

    Full Text Available Objectives : Leptin is an adipose cells derived hormone that regulates energy homeostasis within the body. Energy metabolism of immune cells influences their activity within numerous pathological states, but the effect of leptin on these cells in unclear. On the one hand, it was observed that leptin induces neutrophils chemotaxis and modulates phagocytosis. On the other hand, neutrophils exposed to leptin did not display detectable Ca 2+ ions mobilization or β 2 -integrin upregulation. In this study, we investigated the effect of leptin on the redox homeostasis in lymphocytes and neutrophils. Material and methods : Neutrophils and lymphocytes were isolated by density-gradient centrifugation of blood from healthy volunteers. Cells were cultured with or without leptin (100 ng/ml for lymphocytes and 500 ng/ml for neutrophils or with or without synovial fluid (85% for 0–72 h. Culture media were not changed during incubation. Cells were homogenized and homogenate was frozen until laboratory measurements. Redox homeostasis was assessed by the reduced glutathione (GSH vs. oxidized glutathione (GSSG ratio and membrane lipid peroxidation evaluation. Results : Lymphocytes cultured with leptin and synovial fluid showed a significant increase of the GSSG level. The GSSG/GSH ratio increased by 184 ±37%. In neutrophils incubated in a similar environment, the GSSG/GSH ratio increased by just 21 ±7%, and the effect was observed irrespectively of whether they were exposed to leptin or synovial fluid or both together. Neither leptin nor synovial fluid influenced lipid peroxidation in neutrophils, but in lymphocytes leptin intensified lipid peroxidation. Conclusions : Leptin altered the lymphocytes, but not neutrophils redox state. Because firstly neutrophils are anaerobic cells and have just a few mitochondria and secondly lymphocytes have typical aerobic metabolism, the divergence of our data supports the hypothesis that leptin induces oxidative stress by

  5. Minimally cultured or selected autologous tumor-infiltrating lymphocytes after a lympho-depleting chemotherapy regimen in metastatic melanoma patients.

    Science.gov (United States)

    Besser, Michal J; Shapira-Frommer, Ronnie; Treves, Avraham J; Zippel, Dov; Itzhaki, Orit; Schallmach, Ester; Kubi, Adva; Shalmon, Bruria; Hardan, Izhar; Catane, Raphael; Segal, Eran; Markel, Gal; Apter, Sara; Nun, Alon Ben; Kuchuk, Iryna; Shimoni, Avichai; Nagler, Arnon; Schachter, Jacob

    2009-05-01

    Adoptive cell therapy with autologous tumor-infiltrating lymphocytes (TIL) and high-dose interleukin-2 (IL-2), after nonmyeloablative chemotherapy, has been shown to result in tumor regression in half of refractory metastatic melanoma patients. In the present study, we describe 2 separate clinical protocols. Twelve patients were treated with "Selected"-TIL, as previously reported and 8 patients with the modified version of "Young"-TIL. Selected-TIL protocol required the establishment of multiple T-cell cultures from 1 patient and in vitro selection of cultures secreting interferon-gamma upon antigenic stimulation. In contrast, Young-TIL are minimally cultured T cells with superior in vitro features that do not require further selection. Two of 12 Selected-TIL patients experienced objective clinical responses (1 complete response, 1 partial response). Out of 8 treated Young-TIL patients, 1 experienced complete response, 2 partial response, and 4 patients had disease stabilization. Twenty-one of 33 enrolled Selected-TIL patients were excluded from the protocol, mainly as cultures failed the interferon-gamma selection criteria or due to clinical deterioration, compared with only 3 Young-TIL patients. Expected bone marrow suppression and high-dose IL-2 toxicity were transient. There was no treatment-related mortality. This study vindicates the feasibility and effectiveness of TIL technology and calls for further efforts to implement and enhance this modality. The use of minimally cultured, unselected Young-TIL enables the treatment of most enrolled patients. Although the cohort of Young-TIL patients treated so far is rather small and the follow-up short, the response rate is encouraging.

  6. Insulin receptor degradation is accelerated in cultured lymphocytes from patients with genetic syndromes of extreme insulin resistance

    International Nuclear Information System (INIS)

    McElduff, A.; Hedo, J.A.; Taylor, S.I.; Roth, J.; Gorden, P.

    1984-01-01

    The insulin receptor degradation rate was examined in B lymphocytes that were obtained from peripheral blood of normal subjects and patients with several syndromes of extreme insulin resistance. The insulin receptors were surface labeled using Na 125 I/lactoperoxidase and the cells were returned to incubate in growth media. After varying periods of incubation, aliquots of cells were solubilized and the cell content of labeled receptor subunits were measured by immunoprecipitation with anti-receptor antibodies and NaDodSO4/polyacrylamide gel electrophoresis. In cell lines from four patients in whom the number of insulin receptors was reduced by greater than 90%, the rate of receptor loss was greater than normal (t1/2 equals 3.8 +/- 0.9 h vs. 6.5 +/- 1.2 h; mean +/- SD, P less than 0.01). However, a similar acceleration in receptor degradation was seen in cells from five patients with extreme insulin resistance but low-normal insulin receptor concentration (t1/2 equals 4.4 +/- 0.9 h). Thus, all the patients with genetic syndromes of insulin resistance had accelerated receptor degradation, regardless of their receptor concentration. By contrast, insulin receptors on cultured lymphocytes that were obtained from patients with extreme insulin resistance secondary to autoantibodies to the insulin receptor had normal receptor degradation (t1/2 equals 6.1 +/- 1.9 h). We conclude that (a) accelerated insulin receptor degradation is an additional feature of cells from patients with genetic forms of insulin resistance; (b) that accelerated insulin receptor degradation may explain the low-normal receptor concentrations that were seen in some patients with extreme insulin resistance; and (c) that accelerated degradation does not explain the decreased receptor concentration in patients with very low insulin receptor binding and, therefore, by inference, a defect in receptor synthesis must be present in this subgroup

  7. The dependence of the magnitude of induced adaptive responseon on the dose of pre-irradiation of cultured human lymphocytes under the optimum irradiation time scheme

    International Nuclear Information System (INIS)

    Mortazavi, S.M.J.; Mozdarani, H.

    2000-01-01

    Human lymphocytes exposed to low doses of X-rays, become less susceptible to the induction of chromosome aberrations by subsequent exposure to high doses of X-rays. This has been termed the radioadaptive response. One of the most important questions in the adaptive response studies was that of the possible existence of an optimum adapting dose. Early experiments indicated that this response could be induced by low doses of X-rays from 1 cGy to 20 cGy. Recently, it has been interestingly shown that the time scheme of exposure to adapting and challenge doses plays an important role in determination of the magnitude of the induced adaptive response. In this study, using the optimum irradiation time scheme (24-48), we have monitored the cytogenetic endpoint of chromosome aberrations to assess the magnitude of adaptation to ionizing radiation in the cultured human lymphocytes. Lymphocytes were pre-exposed to an adapting dose of 1-20 cGy at 24 hours, before an acute challenge dose of 1 or 2 Gy at 48 hours. Cells were fixed at 54 hours. Lymphocytes, which were pretreated with 5 as well as 10 cGy adapting doses, had significantly fewer chromosome aberrations. In spite of the fact that lymphocytes of some of our blood donors which were pre-treated with 1 or 20 cGy adapting doses, showed an adaptive response, the pooled data (all donors) indicated that such an induction of adaptive response can not be observed in these lymphocytes. The overall pattern of the induced adaptive response, indicated that in human lymphocyte (at least under the above mentioned irradiation scheme), 5 cGy and 10 cGy adapting doses are the optimum doses. (author)

  8. Selective inhibition of B lymphocytes in TBTC-treated human bone marrow long-term culture.

    NARCIS (Netherlands)

    Carfi', M.; Bowe, G.; Pieters, R.; Gribaldo, L.

    2010-01-01

    Tributyltin chloride (TBTC) is well known for its immunotoxic effect, in particular towards immature thymocytes. TBTC is also known to induce adipocyte differentiation in primary human bone marrow cultures, which is reflected in the decrease in a number of adipocyte-derived cytokines, chemokines and

  9. In vivo synergistic cytogenetic effects of aminophylline on lymphocyte cultures from patients with lung cancer undergoing chemotherapy

    International Nuclear Information System (INIS)

    Mylonaki, Effie; Manika, Katerina; Zarogoulidis, Paul; Domvri, Kalliopi; Voutsas, Vasilis; Zarogoulidis, Kostas; Mourelatos, Dionysios

    2012-01-01

    Highlights: ► SCEs in vivo, a possible predictor of tumor chemoresponse. ► In vivo exposure to combined treatment, applying the SCE assay. ► Aminophylline enhances DNA instability induced by chemotherapy in vivo. ► In vivo synergistic effect of Aminophylline with the chemotherapeutic agents. - Abstract: Background: The anti-cancer and cytogenetic effects of aminophylline (AM) have been demonstrated in several clinical trials. The aim of the present study was to investigate the in vivo cytogenetic effects of AM in newly diagnosed patients with small cell (SCLC) and non-small cell lung cancer (NSCLC), receiving chemotherapy for the first time. Methods: Sister chromatid exchanges (SCEs) and proliferation rate index (PRI) were evaluated in peripheral blood lymphocyte cultures from six patients with SCLC and six patients with NSCLC after the in vitro addition of AM and after the in vivo administration of AM in patients receiving chemotherapy. Results: The in vitro addition of AM significantly increased SCEs only in SCLC patients (p 0.05). Conclusions: These observations suggest that AM enhances the results of concurrently administered chemotherapy by synergistically increasing its cytogenetic effects in patients with lung cancer

  10. Immunoglobulin production induced in vitro by glucocorticoid hormones: T cell-dependent stimulation of immunoglobulin production without B cell proliferation in cultures of human peripheral blood lymphocytes

    International Nuclear Information System (INIS)

    Grayson, J.; Dooley, N.J.; Koski, I.R.; Blaese, R.M.

    1981-01-01

    The direct effects of steroid hormones on the production of immunoglobulins and DNA synthesis by human T and B lymphocytes was evaluated in cultures of peripheral blood mononuclear cells. As detected by a reverse hemolytic plaque assay, the addition of 0.1 mM to 10 nM hydrocortisone to lymphocytes in culture in the absence of other stimulants or mitogens, resulted in the dramatic induction of immunoglobulin production with responses comparable to those seen in similar cultures stimulated with pokeweed mitogen. Steroid-stimulated immunoglobulin production was first seen after 48 h and peaked at 8-10 d of culture. The production of IgG, IgA, and IgM was induced following incubation with steroid. Glucocorticoids, but not estrogens or androgens, were capable of mediating this effect, and only compounds with affinity for the glucocorticoid receptor were active. The induction of immunoglobulin production was dependent on both T cells and monocytes; cultures depleted of either cell type did not produce immunoglobulin when stimulated with glucocorticoid hormones. Proliferation of B cells or T cells could not be detected by [/sup 3/H]thymidine incorporation or total cell recovery from steroid-stimulated cultures, even though such cultures demonstrated marked increases in immunoglobulin production. The mechanism responsible for this functional maturation of B cells to become high rate immunoglobulin producing cells is as yet undefined, although it appears to involve more than merely steroid mediated inactivation of suppressor T cells

  11. Effects of 3-dimensional culture conditions (collagen-chitosan nano-scaffolds) on maturation of dendritic cells and their capacity to interact with T-lymphocytes.

    Science.gov (United States)

    Daneshmandi, Saeed; Dibazar, Shaghayegh Pishkhan; Fateh, Shirin

    2016-01-01

    In the body, there is a natural three-dimensional (3D) microenvironment in which immune cells, including dendritic cells (DC), play their functions. This study evaluated the impact of using collagen-chitosan 3D nano-scaffolds in comparisons to routine 2D culture plates on DC phenotype and functions. Bone marrow-derived DC were cultured on scaffolds and plates and then stimulated with lipopolysaccharide (LPS) or chitosan-based nanoparticles (NP) for 24 h. Thereafter, DC viability, expression of maturation markers and levels of cytokines secretion were evaluated. In another set of studies, the DC were co-cultured with allogenic T-lymphocytes in both the 2D and 3D systems and effects on DC-induction of T-lymphocyte proliferation and cytokine release were analyzed. The results indicated that CD40, CD86 and MHC II marker expression and interleukin (IL)-12, IL-6 and tumor necrosis factor (TNF)-α secretion by DC were enhanced in 3D cultures in comparison to by cells maintained in the 2D states. The data also showed that DNA/chitosan NP activated DC more than LPS in the 3D system. T-Lymphocyte proliferation was induced to a greater extent by DNA/NP-treated DC when both cell types were maintained on the scaffolds. Interestingly, while DC induction of T-lymphocyte interferon (IFN)-γ and IL-4 release was enhanced in the 3D system (relative to controls), there was a suppression of transforming growth factor (TGF)-β production; effects on IL-10 secretion were variable. The results here suggested that collagen-chitosan scaffolds could provide a pro-inflammatory and activator environment to perform studies to analyze effects of exogenous agents on the induction of DC maturation, NP uptake and/or cytokines release, as well as for the ability of these cells to potentially interact with other immune system cells in vitro.

  12. Protective effect of curcumin and its analog on γ-radiation induced DNA damage and lipid peroxidation in cultured human lymphocytes and isolated rat hepatocytes in vitro

    International Nuclear Information System (INIS)

    Menon, Venugopal P.

    2007-01-01

    Ionizing radiation is known to induce oxidative stress through generation of reactive oxygen species (ROS) resulting in an imbalance of the pro-oxidant and antioxidant status in the cells, which is suggested to culminate in cell death. The present work was aimed to evaluate the radioprotective effect of curcumin and its analog on γ-radiation induced toxicity in cultured human lymphocytes and rat hepatocytes. Hepatocytes were isolated from the liver of rats by collagenase perfusion. The cellular changes were estimated using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS), the antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH). The DNA damage was analyzed by comet assay, cytokinesis blocked micro nucleus assay, dicentric aberrations and translocation frequency. Cell cycle distribution and measurement of the percentage of apoptotic cells were performed by flow cytometry analysis. To investigate whether the dietary agents like curcumin and its analog have a role on cell cycle regulation, we analyzed the changes in cell cycle profiles by using fluorescence activated cell sorter. The increase in the severity of DNA damage was observed with the increase dose (1, 2 and 4 Gy) of γ-radiation in cultured lymphocytes and hepatocytes. TBARS were increased significantly, whereas the levels of GSH and antioxidant enzymes were significantly decreased in γ-irradiated hepatocytes and lymphocytes. On pretreatment with curcumin and its analog (1, 5 and 10 μg/ml) showed a significant decrease in the levels of TBARS and DNA damage. The antioxidant enzymes were increased significantly along with the levels of GSH. The maximum protection of hepatocytes and lymphocytes was observed at 10 μg/ml curcumin and 5 μg/ml curcumin analog pretreatment. Thus, pretreatment with curcumin and its analog helps in protecting the normal hepatocytes and lymphocytes against γ-radiation induced cellular

  13. Predicting positional error of MLC using volumetric analysis

    International Nuclear Information System (INIS)

    Hareram, E.S.

    2008-01-01

    IMRT normally using multiple beamlets (small width of the beam) for a particular field to deliver so that it is imperative to maintain the positional accuracy of the MLC in order to deliver integrated computed dose accurately. Different manufacturers have reported high precession on MLC devices with leaf positional accuracy nearing 0.1 mm but measuring and rectifying the error in this accuracy is very difficult. Various methods are used to check MLC position and among this volumetric analysis is one of the technique. Volumetric approach was adapted in our method using primus machine and 0.6cc chamber at 5 cm depth In perspex. MLC of 1 mm error introduces an error of 20%, more sensitive to other methods

  14. Introduction and feasibility study of the HD-270 MLC

    International Nuclear Information System (INIS)

    Kim, Dae Young; Kim Won Taek; Lee, Hwa Jung; Lee, Kang Hyeok

    2003-01-01

    The multileaf collimator(MLC) has many advantages, but use of the MLC increased effective penumbra and isodose undulation in dose distribution compared with that of an alloy block. In this work, we introduced the HD-270 MLC, which can improve the above disadvantages of MLC, and reported its feasibility study. The HD-270 MLC is a technique which combines the use of the existing Siemens multileaf collimator(3D MLC) with patient translation perpendicular to the leaf plane. The technique produces a smoothed isodose distribution with the reduced isodose undulation and effective penumbra. To assess the efficacy of the HD-270 technique and determine the appropriate resolution, a polygonal shaped MLC field was made to produce field edge angles from 0 degree to 75 degree with a step of 15 degree. Each HD-270 group was generated according to the allowed resolution, i. e., 5, 3, and 2 mm. The experiment was carried out on Primus, a Siemens linear accelerator configured with HD-270 MLC. The total 60 MU of 6 MV photon beam was delivered to X-Omat film (Kodak, USA) at a SAD of 100 cm and 1.5 cm depth in solid water phantom. Exposed films were scanned by Lumiscan75(LUMISYS) and analyzed using RIT113 software (Radiological Imaging Technology Inc., USA). To test the mechanical accuracy of table movement, the transverse, longitudinal, and vertical positions were controlled by a consol with ±5 mm, ±4 mm, ±3 mm, and ±2 mm steps, and then measured using a dial gauge with an accuracy of 0.001 inch. During the experiments, the table loaded with about 50 Kg human phantom to simulate the real treatment situation. The effective penumbra and isodose undulation became larger with increase the resolution and field edge angle. The accuracy of the table movement on each direction is good within the ±1 mm. Clinical use of the MLC can be increased by using of the HD-270 MLC which complements to the disadvantages of the MLC.

  15. In vivo synergistic cytogenetic effects of aminophylline on lymphocyte cultures from patients with lung cancer undergoing chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Mylonaki, Effie; Manika, Katerina [Pulmonary Department, “G.Papanikolaou” General Hospital, Aristotle University of Thessaloniki (Greece); Zarogoulidis, Paul, E-mail: pzarog@hotmail.com [Pulmonary Department, “G.Papanikolaou” General Hospital, Aristotle University of Thessaloniki (Greece); Domvri, Kalliopi; Voutsas, Vasilis; Zarogoulidis, Kostas [Pulmonary Department, “G.Papanikolaou” General Hospital, Aristotle University of Thessaloniki (Greece); Mourelatos, Dionysios [Biology and Genetics, Medical School, Aristotle University of Thessaloniki (Greece)

    2012-12-15

    Highlights: ► SCEs in vivo, a possible predictor of tumor chemoresponse. ► In vivo exposure to combined treatment, applying the SCE assay. ► Aminophylline enhances DNA instability induced by chemotherapy in vivo. ► In vivo synergistic effect of Aminophylline with the chemotherapeutic agents. - Abstract: Background: The anti-cancer and cytogenetic effects of aminophylline (AM) have been demonstrated in several clinical trials. The aim of the present study was to investigate the in vivo cytogenetic effects of AM in newly diagnosed patients with small cell (SCLC) and non-small cell lung cancer (NSCLC), receiving chemotherapy for the first time. Methods: Sister chromatid exchanges (SCEs) and proliferation rate index (PRI) were evaluated in peripheral blood lymphocyte cultures from six patients with SCLC and six patients with NSCLC after the in vitro addition of AM and after the in vivo administration of AM in patients receiving chemotherapy. Results: The in vitro addition of AM significantly increased SCEs only in SCLC patients (p < 0.001). The in vivo administration of AM after chemotherapy increased SCEs in both cancer types (SCLC: p < 0.001, NSCLC: p = 0.003) and this increase was synergistic, the rates of SCEs in the presence of AM were higher than the expected SCE values if the increases above background for chemotherapy and AM were independent and additive (SCLC: p < 0.001, NSCLC: p = 0.008). Although in both groups of patients cell division delays were observed after the combined chemotherapy plus in vivo AM treatment, the correlation between the magnitude of the SCE response and the PRI depression was not statistically significant (p > 0.05). Conclusions: These observations suggest that AM enhances the results of concurrently administered chemotherapy by synergistically increasing its cytogenetic effects in patients with lung cancer.

  16. A microculture technique for rat lymphocyte transformation.

    Science.gov (United States)

    Lindsay, V J; Allardyce, R A

    1979-01-01

    We report the development of an economical microculture technique suitable for measuring rat lymphocyte response to mitogens and in mixed lymphocyte reactions. The effects of varying culture conditions, i.e. source of serum, addition and concentration of 2-mercaptoethanol, mitogen concentrations, culture incubation times, absorption of serum, lymphocyte numbers and microtitre plate well shape are described.

  17. An experimental comparison of conventional two-bank and novel four-bank dynamic MLC tracking

    International Nuclear Information System (INIS)

    Davies, G A; Clowes, P; McQuaid, D; Evans, P M; Webb, S; Poludniowski, G

    2013-01-01

    The AccuLeaf mMLC featuring four multileaf-collimator (MLC) banks has been used for the first time for an experimental comparison of conventional two-bank with novel four-bank dynamic MLC tracking of a two-dimensional sinusoidal respiratory motion. This comparison was performed for a square aperture, and for three conformal treatment apertures from clinical radiotherapy lung cancer patients. The system latency of this prototype tracking system was evaluated and found to be 1.0 s and the frequency at which MLC positions could be updated, 1 Hz, and therefore accurate MLC tracking of irregular patient motion would be difficult with the system in its current form. The MLC leaf velocity required for two-bank-MLC and four-bank-MLC tracking was evaluated for the apertures studied and a substantial decrease was found in the maximum MLC velocity required when four-banks were used for tracking rather than two. A dosimetric comparison of the two techniques was also performed and minimal difference was found between two-bank-MLC and four-bank-MLC tracking. The use of four MLC banks for dynamic MLC tracking is shown to be potentially advantageous for increasing the delivery efficiency compared with two-bank-MLC tracking where difficulties are encountered if large leaf shifts are required to track motion perpendicular to the direction of leaf travel. (paper)

  18. Monte Carlo study of MLC fields for cobalt therapy machine

    Directory of Open Access Journals (Sweden)

    Komanduri M Ayyangar

    2014-01-01

    Full Text Available An automated Multi-Leaf Collimator (MLC system has been developed as add-on for the cobalt-60 teletherapy machines available in India. The goal of the present computational study is to validate the MLC design using Monte Carlo (MC modeling. The study was based on the Kirloskar-supplied Phoenix model machines that closely match the Atomic Energy of Canada Limited (AECL theratron-80 machine. The MLC is a retrofit attachment to the collimator assembly, with 14 non-divergent leaf pairs of 40 mm thick, 7 mm wide, and 150 mm long tungsten alloy plates with rounded edges and 20 mm tongue and 2 mm groove in each leaf. In the present work, the source and collimator geometry has been investigated in detail to arrive at a model that best represents the measured dosimetric data. The authors have studied in detail the proto-I MLC built for cobalt-60. The MLC field sizes were MC simulated for 2 × 2 cm 2 to 14 × 14 cm 2 square fields as well as irregular fields, and the percent depth dose (PDD and profile data were compared with ROPS† treatment planning system (TPS. In addition, measured profiles using the IMATRIXX system‡ were also compared with the MC simulations. The proto-I MLC can define radiation fields up to 14 × 14 cm΂ within 3 mm accuracy. The maximum measured leakage through the leaf ends in closed condition was 3.4% and interleaf leakage observed was 7.3%. Good agreement between MC results, ROPS and IMATRIXX results has been observed. The investigation also supports the hypothesis that optical and radiation field coincidence exists for the square fields studied with the MLC. Plots of the percent depth dose (PDD data and profile data for clinically significant irregular fields have also been presented. The MC model was also investigated to speed up the calculations to allow calculations of clinically relevant conformal beams.

  19. Proliferative kinetics and chromosome damage in trisomy 21 lymphocyte cultures exposed to gamma-rays and bleomycin

    International Nuclear Information System (INIS)

    Morimoto, K.; Kaneko, T.; Iijima, K.; Koizumi, A.

    1984-01-01

    Lymphocytes from patients with Down's syndrome (trisomy 21) have been investigated for cell cycle kinetics, cell proliferation delays, and chromosomal aberrations after exposure to gamma-rays or bleomycin. Analysis by sister chromatid differential staining revealed that trisomy 21 lymphocytes started cell cycling about 5 hr earlier than did normal diploid lymphocytes after phytohemagglutinin stimulation as a whole, but that cycling trisomic and normal cells had the same mean cell cycle times. When exposed to gamma-rays or bleomycin in G0, trisomy 21 lymphocytes showed a 30% or, on average, 50% longer duration of cell turnover times, respectively, than normal cells; only bleomycin-treated trisomic cells had a biphasic dose-response. Frequencies of dicentrics and rings in first-division cells after gamma-ray or bleomycin exposure were twice as high in trisomic cells as in normal cells. The frequency of aberrations decreased by 50% (gamma-ray-exposed) or 65 to 85% (bleomycin-treated) through successive divisions; trisomic cells showed a more marked decline in aberration yields compared to normal cells after bleomycin treatment. These data support the idea that circulating lymphocytes in trisomy 21 patients have a shorter average life span or a younger average age

  20. Elimination of radiation-induced chromosome damages in human peripheral blood lymphocyte cultures. 2. The frequency of aberrations in the first-fifth post-irradiation mitosis

    International Nuclear Information System (INIS)

    Pyatkin, E.K.; Pokrovskaya, V.N.; Nugis, V.Yu.

    1982-01-01

    The number of chromosome aberrations in 1.-5. mitoses cultivated from lymphocyte PHA of peripheric man blood after gamma irradiation in vitro in 1e5; 3 and 6 Gy has been determined. For all the doses, as the cells passed 1. and successive postradiation divisiops, observed was the decrease in the number of aberrant metaphases and all the aberrations of the chromosomal typee at that their elimination rate increases with the dose increase. No considerable differences in the frequency of pair fragments in 1.-4. mitosis after irradiation in 1,5 Gy dose, in 1.-3. mitoses after irradiation in 3 Gy dose and in 1.-2. mitoses after irradiation in 6 Gy dose were found. In lymphocyte cultures irradiated in 3 and 6 Gy doses the number of dicentries in 2. mitosis was approximately 2 times smaller than in 1. mitosis and in 3. mitosis two times smaller than in 2. mitosis. In 1. mitosis almost all the dicentrics have accompanying pair fragments in 2. and 3. mitoses a share of the dicentrics without fragments constituted about 30-70 %, and in 4.-5. mitoses amounted to 95-100 %. The reduction of the number of irregular chromosomes in the process of cell passing of 1. and successive postradiation mitosis was noted only during lymphocyte investigation irradiated in 6 Gy. At 1,5 and 3 Gy doses these aberration frequency in 1.-5. and 1.-4. mitoses were nearly the same

  1. Complete transformation of ZnO and CuO nanoparticles in culture medium and lymphocyte cells during toxicity testing

    Science.gov (United States)

    Here, we present evidence on complete transformation of ZnO and CuO nanoparticles, which are among the most heavily studied metal oxide particles, during 24 h in vitro toxicological testing with human T-lymphocytes. Synchrotron radiation-based X-ray absorption near edge st...

  2. Detection of clonal aberrations by cytogenetic analysis after different culture methods and by FISH in 129 patients with Chronic Lymphocytic Leukemia.

    Science.gov (United States)

    Jenderny, Jutta; Goldmann, Claudia; Thede, Rebekka; Ebrecht, Monika; Korioth, Frank

    2014-01-01

    There are only a few cytogenetic analysis (CA) studies that directly compare the novel cultivation technique using immunostimulatory CpG-oligonucleotide DSP30/interleukin-2 (DSP30/IL2) with other culture methods. Therefore, parallel cultures of peripheral blood of 129 chronic lymphocytic leukemia (CLL) patients were set up in unstimulated cultures, in the presence of pokeweed medium (PWM), and with DSP30/IL2. Furthermore, CA results were compared with data obtained by FISH. Clonal aberrations were observed by CA in 6% of the cases in unstimulated cultures, in 27% of the cases with PWM, and in 40% of the cases with DSP30/IL2. Some clonal aberrations were detected by CA only with one culture method. Using 3 different culture methods, clonal aberrations were detected in 41% of the cases by CA and in 71% of the cases by FISH. Altogether, 78% of the cases exhibited clonal aberrations discovered by CA and FISH. Also, CA detected clonal aberrations not targeted by FISH in 7% of the cases, and FISH identified clonal aberrations not detected by CA in 36% of the cases. Our study demonstrates that the combined use of CA with different culture methods together with FISH increases our knowledge of the genetic complexity and heterogeneity in CLL pathogenesis. © 2014 S. Karger AG, Basel.

  3. Influence of MLC leaf width on biologically adapted IMRT plans

    Energy Technology Data Exchange (ETDEWEB)

    Roedal, Jan; Soevik, Aaste; Malinen, Eirik (Dept. of Medical Physics, The Norwegian Radium Hospital, Oslo Univ. Hospital, Oslo (Norway)), E-mail: jan.rodal@radiumhospitalet.no

    2010-10-15

    Introduction. High resolution beam delivery may be required for optimal biology-guided adaptive therapy. In this work, we have studied the influence of multi leaf collimator (MLC) leaf widths on the treatment outcome following adapted IMRT of a hypoxic tumour. Material and methods. Dynamic contrast enhanced MR images of a dog with a spontaneous tumour in the nasal region were used to create a tentative hypoxia map following a previously published procedure. The hypoxia map was used as a basis for generating compartmental gross tumour volumes, which were utilised as planning structures in biologically adapted IMRT. Three different MLCs were employed in inverse treatment planning, with leaf widths of 2.5 mm, 5 mm and 10 mm. The number of treatment beams and the degree of step-and-shoot beam modulation were varied. By optimising the tumour control probability (TCP) function, optimal compartmental doses were derived and used as target doses in the inverse planning. Resulting IMRT dose distributions and dose volume histograms (DVHs) were exported and analysed, giving estimates of TCP and compartmental equivalent uniform doses (EUDs). The impact of patient setup accuracy was simulated. Results. The MLC with the smallest leaf width (2.5 mm) consistently gave the highest TCPs and compartmental EUDs, assuming no setup error. The difference between this MLC and the 5 mm MLC was rather small, while the MLC with 10 mm leaf width gave considerably lower TCPs. When including random and systematic setup errors, errors larger than 5 mm gave only small differences between the MLC types. For setup errors larger than 7 mm no differences were found between non-uniform and uniform dose distributions. Conclusions. Biologically adapted radiotherapy may require MLCs with leaf widths smaller than 10 mm. However, for a high probability of cure it is crucial that accurate patient setup is ensured.

  4. Hyperbolic projections of siemens 3d-mlc leaf paths

    International Nuclear Information System (INIS)

    Menzies, N.

    2004-01-01

    Full text: The Siemens Primus linear accelerator has the option of being fitted with a multi-leaf collimator (3D-MLC) that is marketed as having 'double focus', to achieve a constant dose penumbra for all leaf settings. This is achieved by moving the leaves through arcs (similar to some conventional collimator jaws), as well as shaping the leaf side-faces as divergent planes from the x-ray source. One consequence of the mechanical design of the 3D-MLC is that as individual leaves are moved, their projections from the light / x-ray source to the treatment plane follow paths that are hyperbolic, as shown in the figure below. (The eccentricity of the hyperbola is a function of leaf number / distance from centre.) The trajectories of the MLC leaves were modelled (in a spreadsheet) using geometrical projections of the MLC leaves to the treatment plane, with construction details provided in Siemens documentation. The results were checked against the image of the leaf in the linac light field. This problem belongs to the class of conic sections in mathematics, where the intersection of a plane with both nappes of a double right circular cone results in a hyperbola. The good agreement between the model and the light field image provided confirmation of the MLC construction details. AS/NZS 4434.1:1996 (reproduced from IEC 976:1989) provides specifications for maximum deviation from orthogonality of adjacent edges, which can be interpreted for MLC collimators to parallelism of the direction of leaf travel and the adjacent collimator edge (e.g. Elekta ATS). However for the Siemens 'double focused' MLC, it is demonstrated that the geometrical construction of the MLC militates against the leaf image being used for this kind of test. It is also demonstrated that at last one commercial treatment planning system models the Siemens leaf trajectories linearly. The clinical significance of the error in this model is shown to be negligible. Copyright (2004) Australasian College of

  5. SU-E-T-545: MLC Distance Travelled as a Predictor for Motor Failure

    International Nuclear Information System (INIS)

    Stathakis, S; Defoor, D; Linden, P; Kirby, N; Papanikolaou, N; Mavroidis, P

    2015-01-01

    Purpose: To study the frequency of Multi-Leaf Collimator (MLC) leaf failures, investigate methods to predict them and reduce linac downtime. Methods: A Varian HD120 MLC was used in our study. The hyperterminal MLC errors logged from 06/2012 to 12/2014 were collected. Along with the hyperterminal errors, the MLC motor changes and all other MLC interventions by the linear accelerator engineer were recorded. The MLC dynalog files were also recorded on a daily basis for each treatment and during linac QA. The dynalog files were analyzed to calculate root mean square errors (RMS) and cumulative MLC travel distance per motor. An in-house MatLab code was used to analyze all dynalog files, record RMS errors and calculate the distance each MLC traveled per day. Results: A total of 269 interventions were recorded over a period of 18 months. Of these, 146 included MLC motor leaf change, 39 T-nut replacements, and 84 MLC cleaning sessions. Leaves close to the middle of each side required the most maintenance. In the A bank, leaves A27 to A40 recorded 73% of all interventions, while the same leaves in the B bank counted for 52% of the interventions. On average, leaves in the middle of the bank had their motors changed approximately every 1500m of travel. Finally, it was found that the number of RMS errors increased prior to an MLC motor change. Conclusion: An MLC dynalog file analysis software was developed that can be used to log daily MLC usage. Our eighteen-month data analysis showed that there is a correlation between the distance an MLC travels, the RMS and the life of the MLC motor. We plan to use this tool to predict MLC motor failures and with proper and timely intervention, reduce the downtime of the linac during clinical hours

  6. SU-E-T-545: MLC Distance Travelled as a Predictor for Motor Failure

    Energy Technology Data Exchange (ETDEWEB)

    Stathakis, S; Defoor, D; Linden, P; Kirby, N; Papanikolaou, N [UTHSCSA, San Antonio, TX (United States); Mavroidis, P [University of North Carolina, Chapel Hill, NC (United States)

    2015-06-15

    Purpose: To study the frequency of Multi-Leaf Collimator (MLC) leaf failures, investigate methods to predict them and reduce linac downtime. Methods: A Varian HD120 MLC was used in our study. The hyperterminal MLC errors logged from 06/2012 to 12/2014 were collected. Along with the hyperterminal errors, the MLC motor changes and all other MLC interventions by the linear accelerator engineer were recorded. The MLC dynalog files were also recorded on a daily basis for each treatment and during linac QA. The dynalog files were analyzed to calculate root mean square errors (RMS) and cumulative MLC travel distance per motor. An in-house MatLab code was used to analyze all dynalog files, record RMS errors and calculate the distance each MLC traveled per day. Results: A total of 269 interventions were recorded over a period of 18 months. Of these, 146 included MLC motor leaf change, 39 T-nut replacements, and 84 MLC cleaning sessions. Leaves close to the middle of each side required the most maintenance. In the A bank, leaves A27 to A40 recorded 73% of all interventions, while the same leaves in the B bank counted for 52% of the interventions. On average, leaves in the middle of the bank had their motors changed approximately every 1500m of travel. Finally, it was found that the number of RMS errors increased prior to an MLC motor change. Conclusion: An MLC dynalog file analysis software was developed that can be used to log daily MLC usage. Our eighteen-month data analysis showed that there is a correlation between the distance an MLC travels, the RMS and the life of the MLC motor. We plan to use this tool to predict MLC motor failures and with proper and timely intervention, reduce the downtime of the linac during clinical hours.

  7. Molecular pathogenesis of megalencephalic leukoencephalopathy with subcortical cysts: mutations in MLC1 cause folding defects

    NARCIS (Netherlands)

    Duarri, A.; Teijido, O.; Lopez-Hernandez, T.; Scheper, G.C.; Barriere, H.; Boor, P.K.I.; Aguado, F.; Zorzano, A.; Palacin, M.; Martinez, A; Lukacs, G.L.; van der Knaap, M.S.; Nunes, V.; Estevez, R.

    2008-01-01

    Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare type of leukodystrophy, most often caused by mutations in the MLC1 gene. MLC1 is an oligomeric plasma membrane (PM) protein of unknown function expressed mainly in glial cells and neurons. Most disease-causing missense

  8. Fast regional readout CMOS Image Sensor for dynamic MLC tracking

    Science.gov (United States)

    Zin, H.; Harris, E.; Osmond, J.; Evans, P.

    2014-03-01

    Advanced radiotherapy techniques such as volumetric modulated arc therapy (VMAT) require verification of the complex beam delivery including tracking of multileaf collimators (MLC) and monitoring the dose rate. This work explores the feasibility of a prototype Complementary metal-oxide semiconductor Image Sensor (CIS) for tracking these complex treatments by utilising fast, region of interest (ROI) read out functionality. An automatic edge tracking algorithm was used to locate the MLC leaves edges moving at various speeds (from a moving triangle field shape) and imaged with various sensor frame rates. The CIS demonstrates successful edge detection of the dynamic MLC motion within accuracy of 1.0 mm. This demonstrates the feasibility of the sensor to verify treatment delivery involving dynamic MLC up to ~400 frames per second (equivalent to the linac pulse rate), which is superior to any current techniques such as using electronic portal imaging devices (EPID). CIS provides the basis to an essential real-time verification tool, useful in accessing accurate delivery of complex high energy radiation to the tumour and ultimately to achieve better cure rates for cancer patients.

  9. Fast regional readout CMOS image sensor for dynamic MLC tracking

    International Nuclear Information System (INIS)

    Zin, H; Harris, E; Osmond, J; Evans, P

    2014-01-01

    Advanced radiotherapy techniques such as volumetric modulated arc therapy (VMAT) require verification of the complex beam delivery including tracking of multileaf collimators (MLC) and monitoring the dose rate. This work explores the feasibility of a prototype Complementary metal-oxide semiconductor Image Sensor (CIS) for tracking these complex treatments by utilising fast, region of interest (ROI) read out functionality. An automatic edge tracking algorithm was used to locate the MLC leaves edges moving at various speeds (from a moving triangle field shape) and imaged with various sensor frame rates. The CIS demonstrates successful edge detection of the dynamic MLC motion within accuracy of 1.0 mm. This demonstrates the feasibility of the sensor to verify treatment delivery involving dynamic MLC up to ∼400 frames per second (equivalent to the linac pulse rate), which is superior to any current techniques such as using electronic portal imaging devices (EPID). CIS provides the basis to an essential real-time verification tool, useful in accessing accurate delivery of complex high energy radiation to the tumour and ultimately to achieve better cure rates for cancer patients.

  10. Estudio de la compatibilidad por métodos serológicos (HLA y celulares (CML en 22 años de trabajo en el Instituto de Hematología e Inmunología Study of compatibility by serological(HLAand cellular methods (MLC in 22 years of work in the Hematology and Immunology Institute

    Directory of Open Access Journals (Sweden)

    Luz M Morera Barrios

    2002-12-01

    Full Text Available Se estudió la histocompatibilidad de los loci ABC y del locus D del sistema principal de histocompatibilidad mediante las técnicas serológicas de microlinfocitotoxicidad en 383 pacientes con diferentes enfermedades hematológicas. Se comparó por la técnica celular y la reactividad linfocitaria en el cultivo mixto de linfocitos (CML de 39 de los 145 individuos idénticos para los antígenos HLA, de los estudios familiares realizados en el IHI, de los que resultaron 29 CML negativos, para el 74,35 %. No se correspondieron en el 100 % los estudios serológicos y celulares, ya que no se compatibilizó en todos los casos para los antígenos HLA de clase II, y en ninguno para los antígenos menores de histocompatibilidad, que influyen tanto en los resultados del CML, como en las causas de fracaso del trasplante de médula ósea (TMO en individuos idénticos. Esto corrobora la importancia de los estudios de tipificación de Biología Molecular y antígenos menores de histocompatibilidadThe histocompatibility of loci ABC and locus D of the main histocompatibility system was studied by serological techniques of microlymphocytotoxicity in 383 patients with various hematological diseases. Lymphocyte reactivity was compared in the mixed lymphocyte culture of 39 of 145 identical individuals for HLA antigens, of whom 29 were negative MLC for 74,35%. There was not 100% correspondence between serological and cellular studies since there was no compatibility in all the cases for HLA class II antigens and in any case for minor histocompatibility antigens that influence both the results of MLC and the causes of failed bone marrow transplantation in identical individuals. This confirms the importance of Molecular Biology typing studies and of minor histocompatibility antigens

  11. Evaluating efficiency of coaxial MLC VMAT plan for spine SBRT

    Energy Technology Data Exchange (ETDEWEB)

    Son, Sang Jun; Mun, Jun Ki; Kim, Dae Ho; Yoo, Suk Hyun [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-12-15

    The purpose of the study is to evaluate the efficiency of Coaxial MLC VMAT plan (Using 273° and 350° collimator angle) That the leaf motion direction aligned with axis of OAR (Organ at risk, It means spinal cord or cauda equine in this study.) compare to Universal MLC VMAT plan (using 30° and 330 ° collimator angle) for spine SBRT. The 10 cases of spine SBRT that treated with VMAT planned by Coaxial MLC and Varian TBX were enrolled. Those cases were planned by Eclipse (Ver. 10.0.42, Varian, USA), PRO3 (Progressive Resolution Optimizer 10.0.28) and AAA (Anisotropic Analytic Algorithm Ver. 10.0.28) with coplanar 260 ° arcs and 10MV FFF (Flattening filter free). Each arc has 273° and 350 ° collimator angle, respectively. The Universal MLC VMAT plans are based on existing treatment plans. Those plans have the same parameters of existing treatment plans but collimator angle. To minimize the dose difference that shows up randomly on optimizing, all plans were optimized and calculated twice respectively. The calculation grid is 0.2 cm and all plans were normalized to the target V100%=90%. The indexes of evaluation are V10Gy, D0.03cc, Dmean of OAR (Organ at risk, It means spinal cord or cauda equine in this study.), H.I (Homogeneity index) of the target and total MU. All Coaxial VMAT plans were verified by gamma test with Mapcheck2 (Sun Nuclear Co., USA), Mapphan (Sun Nuclear Co., USA) and SNC patient (Sun Nuclear Co., USA Ver 6.1.2.18513). The difference between the coaxial and the universal VMAT plans are follow. The coaxial VMAT plan is better in the V10Gy of OAR, Up to 4.1%, at least 0.4%, the average difference was 1.9% and In the D0.03cc of OAR, Up to 83.6 cGy, at least 2.2 cGy, the average difference was 33.3 cGy. In Dmean, Up to 34.8 cGy, at least -13.0 cGy, the average difference was 9.6 cGy that say the coaxial VMAT plans are better except few cases. H.I difference Up to 0.04, at least 0.01, the average difference was 0.02 and the difference of average

  12. Management of the interplay effect when using dynamic MLC sequences to treat moving targets

    International Nuclear Information System (INIS)

    Court, Laurence E.; Wagar, Matthew; Ionascu, Dan; Berbeco, Ross; Chin, Lee

    2008-01-01

    Interplay between organ motion and leaf motion has been shown to generally have a small dosimetric impact for most clinical intensity-modulated radiation therapy treatments. However, it has also been shown that for some MLC sequences there can be large daily variations in the delivered dose, depending on details of patient motion or the number of fractions. This study investigates guidelines for dynamic MLC sequences that will keep daily dose variations due to the interplay between organ motion and leaf motion within 10%. Dose distributions for a range of MLC separations (0.2-5.0 cm) and displacements between adjacent MLCs (0-1.5 cm) were exported from ECLIPSE to purpose-written software, which simulated the dose distribution delivered to a moving target. Target motion parallel and perpendicular to the MLC motion was investigated for a range of amplitudes (0.5-4.0 cm), periods (1.5-10 s), and MLC speeds (0.1-3.0 cm/s) with target motions modeled as sin 6 . Results were confirmed experimentally by measuring the dose delivered to an ion chamber array in a moving phantom for different MLC sequences. The simulation results were used to identify MLC sequences that kept dose variations within 10% compared to the dose delivered with no motion. The maximum allowable MLC speed, when target motion is parallel to the MLC motion, was found to be a simple function of target period and MLC separation. When the target motion is perpendicular to MLC motion, the maximum allowable MLC speed can be described as a function of MLC separation and the displacement of adjacent MLCs. These guidelines were successfully applied to two-dimensional motion, and a simple program was written to import MLC sequence files and evaluate whether the maximum daily dose discrepancy caused by the interplay effect will be larger than 10%. This software was experimentally evaluated, and found to conservatively predict whether a given MLC sequence could give large daily dose discrepancies

  13. An MLC calibration method using a detector array

    International Nuclear Information System (INIS)

    Simon, Thomas A.; Kahler, Darren; Simon, William E.; Fox, Christopher; Li, Jonathan; Palta, Jatinder; Liu, Chihray

    2009-01-01

    Purpose: The authors have developed a quantitative calibration method for a multileaf collimator (MLC) which measures individual leaf positions relative to the MLC backup jaw on an Elekta Synergy linear accelerator. Methods: The method utilizes a commercially available two-axis detector array (Profiler 2; Sun Nuclear Corporation, Melbourne, FL). To calibrate the MLC bank, its backup jaw is positioned at the central axis and the opposing jaw is retracted to create a half-beam configuration. The position of the backup jaws field edge is then measured with the array to obtain what is termed the radiation defined reference line. The positions of the individual leaf ends relative to this reference line are then inferred by the detector response in the leaf end penumbra. Iteratively adjusting and remeasuring the leaf end positions to within specifications completes the calibration. Using the backup jaw as a reference for the leaf end positions is based on three assumptions: (1) The leading edge of an MLC leaf bank is parallel to its backup jaw's leading edge, (2) the backup jaw position is reproducible, and (3) the measured radiation field edge created by each leaf end is representative of that leaf's position. Data from an electronic portal imaging device (EPID) were used in a similar analysis to check the results obtained with the array. Results: The relative leaf end positions measured with the array differed from those measured with the EPID by an average of 0.11 ±0.09 mm per leaf. The maximum leaf positional change measured with the Profiler 2 over a 3 month period was 0.51 mm. A leaf positional accuracy of ±0.4 mm is easily attainable through the iterative calibration process. The method requires an average of 40 min to measure both leaf banks. Conclusions: This work demonstrates that the Profiler 2 is an effective tool for efficient and quantitative MLC quality assurance and calibration.

  14. An MLC calibration method using a detector array

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Thomas A.; Kahler, Darren; Simon, William E.; Fox, Christopher; Li, Jonathan; Palta, Jatinder; Liu, Chihray [Department of Nuclear and Radiological Engineering, University of Florida, 202 Nuclear Science Building, Gainesville, Florida 32611-8300 (United States); Sun Nuclear Corporation, 425-A Pineda Court, Melbourne, Florida 32940 (United States) and Department of Radiation Oncology, Health Science Center, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States); Department of Radiation Oncology, Health Science Center, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States); Sun Nuclear Corporation, 425-A Pineda Court, Melbourne, Florida 32940 (United States); Department of Radiation Oncology, Tulane University, 1415 Tulane Ave, HC65, New Orleans, Louisiana 70112 (United States); Department of Radiation Oncology, Health Science Center, University of Florida, P.O. Box 100385, Gainesville, Florida 32610-0385 (United States)

    2009-10-15

    Purpose: The authors have developed a quantitative calibration method for a multileaf collimator (MLC) which measures individual leaf positions relative to the MLC backup jaw on an Elekta Synergy linear accelerator. Methods: The method utilizes a commercially available two-axis detector array (Profiler 2; Sun Nuclear Corporation, Melbourne, FL). To calibrate the MLC bank, its backup jaw is positioned at the central axis and the opposing jaw is retracted to create a half-beam configuration. The position of the backup jaws field edge is then measured with the array to obtain what is termed the radiation defined reference line. The positions of the individual leaf ends relative to this reference line are then inferred by the detector response in the leaf end penumbra. Iteratively adjusting and remeasuring the leaf end positions to within specifications completes the calibration. Using the backup jaw as a reference for the leaf end positions is based on three assumptions: (1) The leading edge of an MLC leaf bank is parallel to its backup jaw's leading edge, (2) the backup jaw position is reproducible, and (3) the measured radiation field edge created by each leaf end is representative of that leaf's position. Data from an electronic portal imaging device (EPID) were used in a similar analysis to check the results obtained with the array. Results: The relative leaf end positions measured with the array differed from those measured with the EPID by an average of 0.11 {+-}0.09 mm per leaf. The maximum leaf positional change measured with the Profiler 2 over a 3 month period was 0.51 mm. A leaf positional accuracy of {+-}0.4 mm is easily attainable through the iterative calibration process. The method requires an average of 40 min to measure both leaf banks. Conclusions: This work demonstrates that the Profiler 2 is an effective tool for efficient and quantitative MLC quality assurance and calibration.

  15. Estudio de la compatibilidad por métodos serológicos (HLA y celulares (CML en 22 años de trabajo en el Instituto de Hematología e Inmunología Compatibility study by serological (HLA and cellular methods (MLC during 22 years of work at the Institute of Hematology and Immunology

    Directory of Open Access Journals (Sweden)

    Luz M Morera Barrios

    2003-12-01

    Full Text Available Se estudió la histocompatibilidad de los loci ABC y del locus D del sistema principal de histocompatibilidad mediante las técnicas serológicas de microlinfocitotoxicidad en 383 pacientes con diferentes enfermedades hematológicas. Se realizó una comparación por la técnica celular y la reactividad linfocitaria en el cultivo mixto de linfocitos (CML, en 39 de los 145 individuos idénticos para los antígenos HLA, tomados de los estudios familiares realizados en el IHI. Resultaron 29 CML negativos, para el 74,35 %. No se corresponden en el 100 % los estudios serológicos y celulares, ya que no se compatibilizó en todos los casos para los antígenos HLA de clase II, y en ninguno para los antígenos menores de histocompatibilidad, que influyen tanto en los resultados del CML y en las causas de fracaso del trasplante de médula ósea (TMO en individuos idénticos. Esto corrobora la importancia de los estudios de tipificación de biología molecular y antígenos menores de histocompatibilidadCompatibility study by serological (HLA and cellular methods (MLC during 22 years of work at the Institute of Hematology and Immunology The histocompatibility of the loci ABC and of the locus D of the main histocompatibility system was studied by the serological techniques of microlymphocytoxicity in 383 patients with different hematological diseases. A comparison was made in 39 of the 145 identical individuals for the HLA antigens obtained from the family studies conducted at the Institute of Hematology and Immunology by using the cellular technique and the lymphocytary reactivity in the mixed lymphocyte culture (MLC. 29 MLC proved to be negative, accounting for 74.35 %. There was not a 100 % correspondance between the serological and cellular studies, since it was not compatibilized in all cases for class II HLA antigens and in no case for the minor histocompatibility antigens that influence on the results of the MLC and on the causes of the failure of

  16. Inhibitory effects of telmisartan on culture and proliferation of and Kv1.3 potassium channel expression in peripheral blood CD4+ T lymphocytes from Xinjiang Kazakh patients with hypertension

    Directory of Open Access Journals (Sweden)

    Sha-Sha Huang

    2016-10-01

    Full Text Available Introduction: Activation of T lymphocytes, for which potassium channels are essential, is involved in the development of hypertension. In this study, we explored the inhibitory effects of telmisartan on the culture and proliferation of and Kv1.3 potassium channel expression in peripheral blood CD4+ T lymphocytes derived from Xinjiang Kazakh patients with hypertension. Methods: CD4+ T-cell samples from hypertensive Kazakh patients and healthy Kazakh people were divided into healthy control, case control, telmisartan, and 4-aminopytidine groups. Changes in the expression levels of interleukin (IL-6 and IL-17 in the blood of the healthy control and case control subjects were detected by enzyme-linked immunosorbent assay. Peripheral blood CD4+ T lymphocytes were first activated and proliferated in vitro and then incubated for 0, 24, and 48 h under various treatment conditions. Thereafter, changes in CD4+ T-lymphocytic proliferation were determined using Cell Counting Kit-8 and microscope photography. Changes in messenger RNA (mRNA and protein expression of the Kv1.3 potassium channel in CD4+ T lymphocytes were detected using real-time quantitative polymerase chain reaction and Western blots, respectively. Results: The IL-6 and IL-17 expression levels were significantly higher in the blood of the hypertensive Kazakh patients than in the healthy Kazakh people. Telmisartan inhibited T-lymphocytic proliferation, as well as the mRNA and protein expression of the Kv1.3 potassium channel in CD4+ T lymphocytes, and the inhibitory effects were time-dependent, with the strongest inhibition observed after 48 h and significantly weaker inhibition observed after 24 h of treatment. Conclusions: Telmisartan may potentially regulate hypertensive inflammatory responses by inhibiting T-lymphocytic proliferation and Kv1.3 potassium channel expression in CD4+ T lymphocytes.

  17. Variation in sister chromatid exchange frequencies between human and pig whole blood, plasma leukocyte, and mononuclear leukocyte cultures

    International Nuclear Information System (INIS)

    Larramendy, M.L.; Reigosa, M.A.

    1986-01-01

    Sister chromatid exchange (SCE) induction by ultraviolet (UV) light was studied in both human and pig whole blood cultures (WBC) and plasma leukocyte cultures (PLC). No variation in SCE frequency was observed between pig WBC and PLC in control as well as in treated cells. Conversely, SCE frequencies of human PLC were consistently higher than those of WBC in control and UV-exposed cells. Thus, red blood cells (RBCs) do not influence the sensitivity of lymphocytes to UV LIGHT exposure, and there must be some different culture condition(s) in the inducation of SCEs between human WBC and PLC but not in swine lymphocyte cultures. Since the BrdUrd/lymphocyte ratio of WBC was halved in PLC, the effect of BrdUrd concentration in inducing the SCE baseline frequency of PLC may be ruled out. Neither the cell separation technique nor polymorphonuclear leukocytes had a significant role in the elevated SCE frequency of human PLC or MLC. Experiments where human RBCs were titrated into human PLC showed that the induction of an elevated SCE frequency of PLC was suppressed in a dose-dependent manner by the presence of RBCs in the culture medium. Since the incorporation of pig or human RBCs into human PLC as well as into MLC reduced the SCE frequency to that of WBC, a common component and/or function existing in these cells is suggested. Analysis of different RBC components showed that RBCs, specifically RBC ghosts, release a diffusible but not dialyzable corrective factor into culture medium that is able to reduce the SCE frequencies of PLC

  18. Antigenotoxic Effect of Curcumin and Carvacrol against Parathion Induced DNA Damage in Cultured Human Peripheral Blood Lymphocytes and Its Relation to GSTM1 and GSTT1 Polymorphism

    Directory of Open Access Journals (Sweden)

    Neeraj Kumar

    2014-01-01

    Full Text Available In recent years, the use of organophosphorus pesticides has been extensively increased and these compounds signify a major class of agricultural pesticides today. We studied antigenotoxic potential of curcumin and carvacrol against the parathion induced DNA damage in cultured peripheral blood lymphocytes using sister chromatid exchanges as a biomarker of genotoxicity. Heparinised fresh blood from healthy individuals was treated with 2.5 μg/mL concentration of parathion in presence of curcumin and carvacrol in order to observe the antigenotoxic potential of both curcumin and carvacrol. Significant reduction (P0.05 of GSTT1 and GSTM1 polymorphism on genotoxicity of parathion and antigenotoxic potential of curcumin and carvacrol.

  19. Avocado fruit (Persea americana Mill) exhibits chemo-protective potentiality against cyclophosphamide induced genotoxicity in human lymphocyte culture.

    Science.gov (United States)

    Paul, Rajkumar; Kulkarni, Paresh; Ganesh, Narayan

    2011-01-01

    Diets rich in fruits and vegetables have been associated with reduced risks for many types of cancers. Avocado (Persea americana Mill.) is a widely consumed fruit containing many cancer preventing nutrients, vitamins and phytochemicals. Studies have shown that phytochemicals extracted from the avocado fruit selectively induce cell cycle arrest, inhibit growth, and induce apoptosis in precancerous and cancer cell lines. Our recent studies indicate that phytochemicals extracted with 50% Methanol from avocado fruits help in proliferation of human lymphocyte cells and decrease chromosomal aberrations induced by cyclophosphamide. Among three concentrations (100 mg, 150 mg and 200 mg per Kg Body Weight), the most effective conc. of extract was 200 mg/Kg Body Wt. It decreased significant level of numerical and structural aberrations (breaks, premature centromeric division etc. up to 88%, p avocado fruit can be utilized for making active chemoprotective ingredient for lowering the side effect of chemotherapy like cyclophosphamide in cancer therapy.

  20. Identification of an MLC suppressor cell population in acute leukemia

    International Nuclear Information System (INIS)

    Bryan, C.F.; Broxmeyer, H.E.; Hansen, J.; Pollack, M.; Dupont, B.

    1978-01-01

    The MLC data from the 20 nonsuppressing patients and the 10 suppressing leukemia patients were analyzed with regard to HLA-A, -B, and -C antigens in the leukemia patients and compared with the presence or absence of suppression. These results demonstrate a significant increase (p < 0.02, Mann-Whitney U test) of HLA antigens Al, A3, and A11 in the leukemia suppressor group. Seven of the 10 leukemia patients showing suppression were A1, A3, or A11, while only 4 of the 20 nonsuppressing leukemia patients carried any of these three HLA-A antigens. The studies demonstrate that a nonspecific suppression of MLC responses is observed in 33% of the patients with acute leukemia

  1. Tumor infiltrating lymphocytes in melanoma comprise high numbers of T-cell clonotypes that are lost during in vitro culture

    DEFF Research Database (Denmark)

    thor Straten, P; Kirkin, A F; Siim, E

    2000-01-01

    -associated peptide epitopes. Cultured TIL have been studied in order to unveil characteristics of TIL and the interactions of TIL and melanoma cells. Whether in vitro cultured TIL mirrors the in situ situation has, however, been questioned. In the present study we have taken advantage of T-cell receptor clonotype...

  2. Implementation and acceptance of dynamic MLC for IMRT and VMAT

    International Nuclear Information System (INIS)

    Garcia, B.; Marquina, J.; Ramirez, J.; Gonzales, A.

    2014-08-01

    The use of Multi-leaf Collimator (MLC) in Intensity-Modulated Radiation Therapy (IMRT) for dynamic treatment techniques as Volumetric Modulated Arc Therapy (VMAT) makes that the movement controls as the speed of the MLC are quantified by means of an acceptance test. The objective determination of the operation regulations of the radiotherapy equipment requires ideally the establishment of the quantitative relationship among the performance deviations and clinical results or some acceptable substitute. Different protocols exist detailed with parameters and acceptance ranges according to the MLC thickness. In our case the acceptance test was carried out for 120-MLC of Trilogy equipment brand Varian. For all the test were used 300-200 Um for each formed beam lets; source-surface distance (SSD) of 100 cm. 9 acceptance tests were used each one with different purposes like to quantify, synchronization, stability, complexity, precision, positioning, conformity, dynamic movements for the case of dynamic wedges, consecutive moves, among others, for the measurements were used film badges dosimetry (Gafchromic Ebt-3 scanner Epson expression 10000 XL); additionally the results were compared with a diodes arrangement Map-Check 2 brand Sun Nuclear; that consists of 1527 diodes prepared in a field of 32 x 26 cm located at a distance of 1 cm parallel, 0.5 cm diagonally. All the developed tests were inside the acceptance tolerance parameters when comparing the obtained result regarding the badges and the Map-Check was found a discrepancy of 0.01%, what gives a treatment certainty to the moment to impart volumetric dose in dynamic fields to the patients. (Author)

  3. The transcription factor Mlc promotes Vibrio cholerae biofilm formation through repression of phosphotransferase system components.

    Science.gov (United States)

    Pickering, Bradley S; Lopilato, Jane E; Smith, Daniel R; Watnick, Paula I

    2014-07-01

    The phosphoenol phosphotransferase system (PTS) is a multicomponent signal transduction cascade that regulates diverse aspects of bacterial cellular physiology in response to the availability of high-energy sugars in the environment. Many PTS components are repressed at the transcriptional level when the substrates they transport are not available. In Escherichia coli, the transcription factor Mlc (for makes large colonies) represses transcription of the genes encoding enzyme I (EI), histidine protein (HPr), and the glucose-specific enzyme IIBC (EIIBC(Glc)) in defined media that lack PTS substrates. When glucose is present, the unphosphorylated form of EIIBC(Glc) sequesters Mlc to the cell membrane, preventing its interaction with DNA. Very little is known about Vibrio cholerae Mlc. We found that V. cholerae Mlc activates biofilm formation in LB broth but not in defined medium supplemented with either pyruvate or glucose. Therefore, we questioned whether V. cholerae Mlc functions differently than E. coli Mlc. Here we have shown that, like E. coli Mlc, V. cholerae Mlc represses transcription of PTS components in both defined medium and LB broth and that E. coli Mlc is able to rescue the biofilm defect of a V. cholerae Δmlc mutant. Furthermore, we provide evidence that Mlc indirectly activates transcription of the vps genes by repressing expression of EI. Because activation of the vps genes by Mlc occurs under only a subset of the conditions in which repression of PTS components is observed, we conclude that additional inputs present in LB broth are required for activation of vps gene transcription by Mlc. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  4. Restoration of lymphocyte proliferation and CTL generation by murine rIL-2 after treatment of allogeneic stimulator cells by ultraviolet B irradiation, heat, or paraformaldehyde

    International Nuclear Information System (INIS)

    Flye, M.W.; Yu, S.

    1991-01-01

    Following a 5-day mixed lymphocyte culture (MLC), C3H/HeJ (H-2k) splenocytes stimulated with DBA/2 (H-2d) gamma-irradiated splenocytes (2000 rads) are specifically cytotoxic in a 4-hr 51 Cr-release assay to P815 (H-2d) target cells (62 +/- 2% cytolysis) but not to third-party EL4 (H-2b). However, when the DBA/2 stimulator cells were treated with heat inactivation (45 degree C for 1 hr), fixed with 1% paraformaldehyde (15 min), or irradiated with ultraviolet-B light (10(4) J/M2), no cell proliferation or cytolytic activity developed in the MLCs. The levels of IL-1, IL-2, and IL-6 from the supernatants of MLC using stimulators undergoing either of the three treatments were markedly decreased compared with that from gamma-irradiated stimulators. Both cell proliferation and specific cytolysis were restored in a dose-dependent fashion by the addition of murine rIL-2 to the MLCs. If the stimulator cells were first activated with 5 micrograms/ml pokeweed mitogen or lipopolysaccharide for 2 days, the subsequent treatment with heat, paraformaldehyde, or UV-B did not significantly affect the development of cytolysis (54-70% cytolysis). Suppressor cells were not detected when cells from the nonresponsive MLCs (2.5 x 10(6) cells) were added to an MLC freshly prepared with gamma-irradiated stimulator cells, or were injected intraperitoneally (50 x 10(6) cells) into naive mice 2 days before recovery and in vitro sensitization of splenocytes. Therefore, modification of the stimulating alloantigen can prevent the release of cytokines that function as an essential second signal in the development of the proliferative response and subsequent cytolysis. The cytokine found to be essential for restoration of this response is IL-2

  5. Implementation and acceptance of dynamic MLC for IMRT and VMAT; Implementacion y aceptacion de MLC dinamicos para IMRT y VMAT

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, B.; Marquina, J.; Ramirez, J.; Gonzales, A., E-mail: bertha.garcia@aliada.com.pe [ALIADA, Oncologia Integral, Av. Jose Galvez Barrenechea 1044, San Isidro, Lima 27 (Peru)

    2014-08-15

    The use of Multi-leaf Collimator (MLC) in Intensity-Modulated Radiation Therapy (IMRT) for dynamic treatment techniques as Volumetric Modulated Arc Therapy (VMAT) makes that the movement controls as the speed of the MLC are quantified by means of an acceptance test. The objective determination of the operation regulations of the radiotherapy equipment requires ideally the establishment of the quantitative relationship among the performance deviations and clinical results or some acceptable substitute. Different protocols exist detailed with parameters and acceptance ranges according to the MLC thickness. In our case the acceptance test was carried out for 120-MLC of Trilogy equipment brand Varian. For all the test were used 300-200 Um for each formed beam lets; source-surface distance (SSD) of 100 cm. 9 acceptance tests were used each one with different purposes like to quantify, synchronization, stability, complexity, precision, positioning, conformity, dynamic movements for the case of dynamic wedges, consecutive moves, among others, for the measurements were used film badges dosimetry (Gafchromic Ebt-3 scanner Epson expression 10000 XL); additionally the results were compared with a diodes arrangement Map-Check 2 brand Sun Nuclear; that consists of 1527 diodes prepared in a field of 32 x 26 cm located at a distance of 1 cm parallel, 0.5 cm diagonally. All the developed tests were inside the acceptance tolerance parameters when comparing the obtained result regarding the badges and the Map-Check was found a discrepancy of 0.01%, what gives a treatment certainty to the moment to impart volumetric dose in dynamic fields to the patients. (Author)

  6. TomoTherapy MLC verification using exit detector data

    Energy Technology Data Exchange (ETDEWEB)

    Chen Quan; Westerly, David; Fang Zhenyu; Sheng, Ke; Chen Yu [TomoTherapy Inc., 1240 Deming Way, Madison, Wisconsin 53717 (United States); Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado 80045 (United States); Xinghua Cancer Hospital, Xinghua, Jiangsu 225700 (China); Department of Radiation Oncology, University of California-Los Angeles, Los Angeles, California 90095 (United States); TomoTherapy Inc., 1240 Deming Way, Madison, Wisconsin 53717 (United States)

    2012-01-15

    Purpose: Treatment delivery verification (DV) is important in the field of intensity modulated radiation therapy (IMRT). While IMRT and image guided radiation therapy (IGRT), allow us to create more conformal plans and enables the use of tighter margins, an erroneously executed plan can have detrimental effects on the treatment outcome. The purpose of this study is to develop a DV technique to verify TomoTherapy's multileaf collimator (MLC) using the onboard mega-voltage CT detectors. Methods: The proposed DV method uses temporal changes in the MVCT detector signal to predict actual leaf open times delivered on the treatment machine. Penumbra and scattered radiation effects may produce confounding results when determining leaf open times from the raw detector data. To reduce the impact of the effects, an iterative, Richardson-Lucy (R-L) deconvolution algorithm is applied. Optical sensors installed on each MLC leaf are used to verify the accuracy of the DV technique. The robustness of the DV technique is examined by introducing different attenuation materials in the beam. Additionally, the DV technique has been used to investigate several clinical plans which failed to pass delivery quality assurance (DQA) and was successful in identifying MLC timing discrepancies as the root cause. Results: The leaf open time extracted from the exit detector showed good agreement with the optical sensors under a variety of conditions. Detector-measured leaf open times agreed with optical sensor data to within 0.2 ms, and 99% of the results agreed within 8.5 ms. These results changed little when attenuation was added in the beam. For the clinical plans failing DQA, the dose calculated from reconstructed leaf open times played an instrumental role in discovering the root-cause of the problem. Throughout the retrospective study, it is found that the reconstructed dose always agrees with measured doses to within 1%. Conclusions: The exit detectors in the TomoTherapy treatment

  7. TomoTherapy MLC verification using exit detector data

    International Nuclear Information System (INIS)

    Chen Quan; Westerly, David; Fang Zhenyu; Sheng, Ke; Chen Yu

    2012-01-01

    Purpose: Treatment delivery verification (DV) is important in the field of intensity modulated radiation therapy (IMRT). While IMRT and image guided radiation therapy (IGRT), allow us to create more conformal plans and enables the use of tighter margins, an erroneously executed plan can have detrimental effects on the treatment outcome. The purpose of this study is to develop a DV technique to verify TomoTherapy's multileaf collimator (MLC) using the onboard mega-voltage CT detectors. Methods: The proposed DV method uses temporal changes in the MVCT detector signal to predict actual leaf open times delivered on the treatment machine. Penumbra and scattered radiation effects may produce confounding results when determining leaf open times from the raw detector data. To reduce the impact of the effects, an iterative, Richardson-Lucy (R-L) deconvolution algorithm is applied. Optical sensors installed on each MLC leaf are used to verify the accuracy of the DV technique. The robustness of the DV technique is examined by introducing different attenuation materials in the beam. Additionally, the DV technique has been used to investigate several clinical plans which failed to pass delivery quality assurance (DQA) and was successful in identifying MLC timing discrepancies as the root cause. Results: The leaf open time extracted from the exit detector showed good agreement with the optical sensors under a variety of conditions. Detector-measured leaf open times agreed with optical sensor data to within 0.2 ms, and 99% of the results agreed within 8.5 ms. These results changed little when attenuation was added in the beam. For the clinical plans failing DQA, the dose calculated from reconstructed leaf open times played an instrumental role in discovering the root-cause of the problem. Throughout the retrospective study, it is found that the reconstructed dose always agrees with measured doses to within 1%. Conclusions: The exit detectors in the TomoTherapy treatment systems

  8. T-lymphocyte dependency of B-lymphocyte blastogenic response to phytomitogens

    International Nuclear Information System (INIS)

    Han, T.; Dadey, B.

    1978-01-01

    Human peripheral blood T and B lymphocytes were separated by a method based on the stable rosette formation of T lymphocytes with neuraminidase-treated sheep erythrocytes, followed by centrifugation over a Ficoll-Hypaque gradient. Monocytes were isolated from the T-depleted B lymphocyte preparation by allowing the monocytes to ingest iron particles and by subsequent centrifugation over a Ficoll-Hypaque gradient. The T lymphocytes responded extremely well to PHA and very well to PWM, while the B lymphocytes were unresponsive to either PHA or PWM. However, when the B lymphocytes were cultured together with irradiated autologous or allogeneic T lymphocytes (1 : 1,1:2 or 1 : 4 ratio), both PHA and PWM became mitogenic to B lymphocytes. Irradiated T lymphocytes alone did not respond to either PHA or PWM, indicating that the 3 H-thymidine incorporation seen in the mixed-cell culture was due to the activation of unirradiated B lymphocytes. The B lymphocytes failed to respond to these phytomitogens in the presence of lower concentrations of irradiated T lymphocytes. The monocytes were found to be incapable of helping the B lymphocytes to respond to PHA or PWM. (author)

  9. A new assay for cytotoxic lymphocytes, based on a radioautographic readout of 111In release, suitable for rapid, semi-automated assessment of limit-dilution cultures

    International Nuclear Information System (INIS)

    Shortman, K.; Wilson, A.

    1981-01-01

    A new assay for cytotoxic T lymphocytes is described, of general application, but particularly suitable for rapid, semi-automated assessment of multiple microculture tests. Target cells are labelled with high efficiency and to high specific activity with the oxine chelate of 111 indium. After a 3-4 h incubation of test cells with 5 X 10 3 labelled target cells in V wells of microtitre trays, samples of the supernatant are spotted on paper (5 μl) or transferred to soft-plastic U wells (25-50 μl) and the 111 In release assessed by radioautography. Overnight exposure of X-ray film with intensifying screens at -70 0 C gives an image which is an intense dark spot for maximum release, a barely visible darkening with the low spontaneous release, and a definite positive with 10% specific lysis. The degree of film darkening, which can be quantitated by microdensitometry, shows a linear relationship with cytotoxic T lymphocyte dose up to the 40% lysis level. The labelling intensity and sensitivity can be adjusted over a wide range, allowing a single batch of the short half-life isotope to serve for 2 weeks. The 96 assays from a single tray are developed simultaneously on a single small sheet of film. Many trays can be processed together, and handling is rapid if 96-channel automatic pipettors are used. The method allows rapid visual scanning for positive and negative limit dilution cultures in cytotoxic T cell precursor frequency and specificity studies. In addition, in conjunction with an automated densitometer designed to scan microtitre trays, the method provides an efficient alternative to isotope counting in routine cytotoxic assays. (Auth.)

  10. As to the clastogenic-, sister-chromatid exchange inducing-and cytotoxic activity of inosine triphosphate in cultures of human peripheral lymphocytes.

    Science.gov (United States)

    Vormittag, W; Brannath, W

    2001-05-09

    The influence of commercial inosine triphosphate (ITP) on the chromosome aberration rate, the mitotic rate, sister-chromatid exchange (SCE) frequency, and the proportion of first (X1), second (X2) and third (X3) division metaphases was investigated in 72h cultures of human peripheral lymphocytes. The blood donors had mild inactive arthrosis and a normal health check-up. All cultures of each volunteer were set-up simultaneously. In contrast to a previous report [Arch. Biochem. Biophys. 278 (1990) 238-244], it was demonstrated in two preliminary studies (number of subjects, n=5 each) that ITP at a final concentration of 100 microM does not induce chromosomal aberrations and, furthermore, that not ITP concentrations higher than 100 microM but ITP doses higher than 3.8mM prohibit culture growth. Based on these results, cultures with a final ITP concentration of 3.6mM (max.) and 1.8mM (max./2) were compared with control cultures (number of subjects n=10; three males and seven females, mean age x=57.6 years). Whereas no increase in the chromosomal breakage rate was observed in cultures with an ITP concentration of 1.8mM and only a marginally significant one (P=0.048) for 3.6mM ITP cultures, a highly significant induction of SCEs, not only at an ITP concentration of 3.6mM (Prate from 0 to 1.8mM as well as from 1.8 to 3.6mM in the aberration studies (all P values are equal to smallest possible one for a sample size of 10, namely, 0.002), and in the SCE studies there is a significant decrease in the X3 frequency when ITP is increased (0-1.8mM: P=0.0061 and 1.8-3.6mM: Pchanges significantly only at the second dose step (0-1.8mM ITP: P=0.22 and 1.8-3.6mM ITP: P<0.0001). The results are discussed.

  11. Evaluation of spontaneous and radiation-induced micronucleus frequency in cultured human peripheral blood lymphocytes depending on age and sex

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, H. J.; Kang, C. M.; Chung, H. C. [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)] (and others)

    2002-12-15

    The goal of this study was to provide data on the dose-dependent production of MicroNucleus (MN) in human lymphocytes irradiated with {sup 60}Co {gamma}-rays and 50MeV neutron, and to evaluate predictive markers of intrinsic radiosensitivity in individuals for monitoring occupational or environmental radiation exposure. For the dose-response study, heparinized whole blood of 10 healthy volunteers was irradiated with {sup 60}Co {gamma}-rays employing of 0.25-8Gy. The MNs were observed all doses, and the numerical changes according to doses. In dose-response curves fit linear-quadratic form (alpha =0.31{+-}0.049, beta =0.0022{+-}0.0022) for {gamma}-rays, but (alpha=0.99{+-}0.528, beta =0.0093{+-}0.0047) for neutron. Neutrons were than {gamma}-rays effective in producing MN with dose-dependent manner. The frequency of MN varies with dose. The RBE (Relative Biological Effectiveness) for micronuclei was 2.370.17. Further studies were carried out to provide evidence for the existence of individual variations in age-dependent responses to radiation. Spontaneous and radiation-induced MN varies greatly among individuals, and little is known about the molecular mechanisms of this variability. It was shown that the increased level of spontaneous cell with MN was observed with increasing age. The relationship between radiosensitivity and the increased spontaneous level of MN may be in inverse proportion. These studies indicated that the MN assay have a high potential as a rapid, sensitive and accurate method which can be used to monitor a large population exposed to radiation for rapid triage in the case of a large-scale accident.

  12. Correlation between base-excision repair gene polymorphisms and levels of in-vitro BPDE-induced DNA adducts in cultured peripheral blood lymphocytes.

    Directory of Open Access Journals (Sweden)

    Hongping Yu

    Full Text Available In vitro benzo[a]pyrene diol epoxide (BPDE-induced DNA adducts in cultured peripheral lymphocytes have been shown to be a phenotypic biomarker of individual's DNA repair phenotype that is associated with cancer risk. In this study, we explored associations between genotypes of base-excision repair genes (PARP1 Val762Ala, APEX1 Asp148Glu, and XRCC1 Arg399Gln and in vitro BPDE-induced DNA adducts in cultured peripheral blood lymphocytes in 706 cancer-free non-Hispanic white subjects. We found that levels of BPDE-induced DNA adducts were significantly higher in ever smokers than in never smokers and that individuals with the Glu variant genotypes (i.e., Asp/Glu and Glu/Glu exhibited lower levels of BPDE-induced DNA adducts than did individuals with the common Asp/Asp homozygous genotype (median RAL levels: 32.0 for Asp/Asp, 27.0 for Asp/Glu, and 17.0 for Glu/Glu, respectively; P(trend = 0.030. Further stratified analysis showed that compared with individuals with the common APEX1-148 homozygous Asp/Asp genotype, individuals with the APEX1-148Asp/Glu genotype or the Glu/Glu genotype had a lower risk of having higher-level adducts (adjusted OR = 0.60, 95% CI: 0.36-0.98 and adjusted OR = 0.47, 95% CI: 0.26-0.86, respectively; P(trend = 0.012 among smokers. Such an effect was not observed in non-smokers. However, there was no significant interaction between the APEX1 Asp148Glu polymorphism and smoking exposure in this study population (P = 0.512. Additional genotype-phenotype analysis found that the APEX1-148Glu allele had significantly increased expression of APEX1 mRNA in 270 Epstein-Barr virus-transformed lymphoblastoid cell lines, which is likely associated with more active repair activity. Our findings suggest that the functional APEX1-148Glu allele is associated with reduced risk of having high levels of BPDE-induced DNA adducts mediated with high levels of mRNA expression.

  13. Leaf transmission reduction using moving jaws for dynamic MLC IMRT

    International Nuclear Information System (INIS)

    Schmidhalter, D.; Fix, M. K.; Niederer, P.; Mini, R.; Manser, P.

    2007-01-01

    The aim of this work is to investigate to what extent it is possible to use the secondary collimator jaws to reduce the transmitted radiation through the multileaf collimator (MLC) during an intensity modulated radiation therapy (IMRT). A method is developed and introduced where the jaws follow the open window of the MLC dynamically (dJAW method). With the aid of three academic cases (Closed MLC, Sliding-gap, and Chair) and two clinical cases (prostate and head and neck) the feasibility of the dJAW method and the influence of this method on the applied dose distributions are investigated. For this purpose the treatment planning system Eclipse and the Research-Toolbox were used as well as measurements within a solid water phantom were performed. The transmitted radiation through the closed MLC leads to an inhomogeneous dose distribution. In this case, the measured dose within a plane perpendicular to the central axis differs up to 40% (referring to the maximum dose within this plane) for 6 and 15 MV. The calculated dose with Eclipse is clearly more homogeneous. For the Sliding-gap case this difference is still up to 9%. Among other things, these differences depend on the depth of the measurement within the solid water phantom and on the application method. In the Chair case, the dose in regions where no dose is desired is locally reduced by up to 50% using the dJAW method instead of the conventional method. The dose inside the chair-shaped region decreased up to 4% if the same number of monitor units (MU) as for the conventional method was applied. The undesired dose in the volume body minus the planning target volume in the clinical cases prostate and head and neck decreased up to 1.8% and 1.5%, while the number of the applied MU increased up to 3.1% and 2.8%, respectively. The new dJAW method has the potential to enhance the optimization of the conventional IMRT to a further step

  14. Effects of inhibitors of DNA repair on the frequencies of chromosomal aberrations induced by x-rays or alkylating agents in cultured human lymphocytes

    International Nuclear Information System (INIS)

    Kihlman, B.A.; Andersson, H.C.

    1986-01-01

    In the first part of this presentation the authors give examples of the synergistic enhancements that are obtained with various inhibitor combinations in G/sub 2/. The second part of the presentation deals with the effects of two agents, also well known for their capacity to potentiate the frequency of chromosomal aberrations induced by physical and chemical agents, but with a different mechanism of action. These agents are caffeine and 3-aminobenzamide (3AB). Caffeine has for decades been used as an inhibitor of DNA repair although its mechanism of action has not been fully understood. 3AB has more recently come into focus as an efficient inhibitor of the synthesis of poly-(ADP-ribose), a substance believed to be of importance in connection with the repair of certain types of DNA damage. The results presented do not quite fit in with the general idea about the mode of action of these agents. All experiments were carried out with whole-blood cultures of human lymphocytes. When inhibitors were used as post-treatments, chromosomal aberrations were induced by X-rays or by the alkylating agents thiotepa (TT) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). X-rays were generated by a Siemens Stabilipan 200 apparatus, at a dose rate of 0.5 Gy/min. The tube (TR 200f) was operated at 180 kV, 10 mA and the radiation filtered through 4 mm Al

  15. T-cell receptor v-alpha and v-Beta gene usage in interleukin-2-cultured tumor-infiltrating lymphocytes from patients with breast-cancer

    DEFF Research Database (Denmark)

    Andersen, E; Scholler, J; Straten, P

    1994-01-01

    Tumor-infiltrating lymphocytes (TIL) are often found in malignant breast tumors, and have been claimed to be of prognostic value. It has been proposed that TIL may represent an enriched population of tumor-specific cytotoxic lymphocytes, reacting with antigenic determinants on the tumor cell...

  16. A quantitative method to the analysis of MLC leaf position and speed based on EPID and EBT3 film for dynamic IMRT treatment with different types of MLC.

    Science.gov (United States)

    Li, Yinghui; Chen, Lixin; Zhu, Jinhan; Wang, Bin; Liu, Xiaowei

    2017-07-01

    A quantitative method based on the electronic portal imaging system (EPID) and film was developed for MLC position and speed testing; this method was used for three MLC types (Millennium, MLCi, and Agility MLC). To determine the leaf position, a picket fence designed by the dynamic (DMLC) model was used. The full-width half-maximum (FWHM) values of each gap measured by EPID and EBT3 were converted to the gap width using the FWHM versus nominal gap width relationship. The algorithm developed for the picket fence analysis was able to quantify the gap width, the distance between gaps, and each individual leaf position. To determine the leaf speed, a 0.5 × 20 cm 2 MLC-defined sliding gap was applied across a 14 × 20 cm 2 symmetry field. The linacs ran at a fixed-dose rate. The use of different monitor units (MUs) for this test led to different leaf speeds. The effect of leaf transmission was considered in a speed accuracy analysis. The difference between the EPID and film results for the MLC position is less than 0.1 mm. For the three MLC types, twice the standard deviation (2 SD) is provided; 0.2, 0.4, and 0.4 mm for gap widths of three MLC types, and 0.1, 0.2, and 0.2 mm for distances between gaps. The individual leaf positions deviate from the preset positions within 0.1 mm. The variations in the speed profiles for the EPID and EBT3 results are consistent, but the EPID results are slightly better than the film results. Different speeds were measured for each MLC type. For all three MLC types, speed errors increase with increasing speed. The analysis speeds deviate from the preset speeds within approximately 0.01 cm s -1 . This quantitative analysis of MLC position and speed provides an intuitive evaluation for MLC quality assurance (QA). © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  17. Immunoregulatory effects of human dental pulp-derived stem cells on T cells: comparison of transwell co-culture and mixed lymphocyte reaction systems.

    Science.gov (United States)

    Demircan, Pinar Cetinalp; Sariboyaci, Ayla Eker; Unal, Zehra Seda; Gacar, Gulcin; Subasi, Cansu; Karaoz, Erdal

    2011-11-01

    BACKGROUND AIMS. Studies performed using human and animal models have indicated the immunoregulatory capability of mesenchymal stromal cells in several lineages. We investigated whether human dental pulp-derived stem cells (hDP-SC) have regulatory effects on phytohemagglutinin (PHA)-activated CD3(+) T cells. We aimed to define the regulatory mechanisms associated with hDP-SC that occur in mixed lymphocyte reaction (MLR) and transwell systems with PHA-CD3(+) T cells and hDP-SC at a ratio of 1:1. METHODS. Proliferation, apoptosis and pro- and anti-inflammatory cytokines of PHA-CD3(+)T cells, the expression of Regulatory T cells (Treg) markers and some regulatory factors related to hDP-SC, were studied in Both transwell and MLR are co-cultures systems. RESULTS. Anti-proliferative and apoptotic effects of hDP-SC were determined in co-culture systems. Elevated expression levels of human leukocyte antigen (HLA)-G, hepatocyte growth factor (HGF)-β1, intracellular adhesion molecule (ICAM-1)-1, interleukin (IL)-6, IL-10, transforming growth factor (TGF)-β1, vascular adhesion molecule (VCAM)-1 and vascular endothelial growth factor (VEGF) by hDP-SC were detected in the co-culture systems. We observed decreased expression levels of pro-inflammatory cytokines [interferon (IFN)-γ, IL-2, IL-6 receptor (R), IL-12, Interleukin-17A (IL-17A), tumor necrosis factor (TNF)-α] and increased expression levels of anti-inflammatory cytokine [inducible protein (IP)-10] from PHA-CD3(+) T cells in the transwell system. Expression of Treg (CD4(+) CD25(+) Foxp3(+)) markers was significantly induced by hDP-SC in both co-culture systems. We observed apoptosis of PHA-CD3(+) T cells with 24 h using time-lapse camera photographs and active caspase labeling; it is likely that paracrine soluble factors and molecular signals secreted by hDP-SC led this apoptosis. CONCLUSIONS. We suggest that hDP-SC have potent immunoregulatory functions because of their soluble factors and cytokines via paracrine

  18. Combining MLC and SVM Classifiers for Learning Based Decision Making: Analysis and Evaluations.

    Science.gov (United States)

    Zhang, Yi; Ren, Jinchang; Jiang, Jianmin

    2015-01-01

    Maximum likelihood classifier (MLC) and support vector machines (SVM) are two commonly used approaches in machine learning. MLC is based on Bayesian theory in estimating parameters of a probabilistic model, whilst SVM is an optimization based nonparametric method in this context. Recently, it is found that SVM in some cases is equivalent to MLC in probabilistically modeling the learning process. In this paper, MLC and SVM are combined in learning and classification, which helps to yield probabilistic output for SVM and facilitate soft decision making. In total four groups of data are used for evaluations, covering sonar, vehicle, breast cancer, and DNA sequences. The data samples are characterized in terms of Gaussian/non-Gaussian distributed and balanced/unbalanced samples which are then further used for performance assessment in comparing the SVM and the combined SVM-MLC classifier. Interesting results are reported to indicate how the combined classifier may work under various conditions.

  19. Combining MLC and SVM Classifiers for Learning Based Decision Making: Analysis and Evaluations

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    2015-01-01

    Full Text Available Maximum likelihood classifier (MLC and support vector machines (SVM are two commonly used approaches in machine learning. MLC is based on Bayesian theory in estimating parameters of a probabilistic model, whilst SVM is an optimization based nonparametric method in this context. Recently, it is found that SVM in some cases is equivalent to MLC in probabilistically modeling the learning process. In this paper, MLC and SVM are combined in learning and classification, which helps to yield probabilistic output for SVM and facilitate soft decision making. In total four groups of data are used for evaluations, covering sonar, vehicle, breast cancer, and DNA sequences. The data samples are characterized in terms of Gaussian/non-Gaussian distributed and balanced/unbalanced samples which are then further used for performance assessment in comparing the SVM and the combined SVM-MLC classifier. Interesting results are reported to indicate how the combined classifier may work under various conditions.

  20. Comparison of MLC error sensitivity of various commercial devices for VMAT pre-treatment quality assurance.

    Science.gov (United States)

    Saito, Masahide; Sano, Naoki; Shibata, Yuki; Kuriyama, Kengo; Komiyama, Takafumi; Marino, Kan; Aoki, Shinichi; Ashizawa, Kazunari; Yoshizawa, Kazuya; Onishi, Hiroshi

    2018-05-01

    The purpose of this study was to compare the MLC error sensitivity of various measurement devices for VMAT pre-treatment quality assurance (QA). This study used four QA devices (Scandidos Delta4, PTW 2D-array, iRT systems IQM, and PTW Farmer chamber). Nine retrospective VMAT plans were used and nine MLC error plans were generated for all nine original VMAT plans. The IQM and Farmer chamber were evaluated using the cumulative signal difference between the baseline and error-induced measurements. In addition, to investigate the sensitivity of the Delta4 device and the 2D-array, global gamma analysis (1%/1, 2%/2, and 3%/3 mm), dose difference (1%, 2%, and 3%) were used between the baseline and error-induced measurements. Some deviations of the MLC error sensitivity for the evaluation metrics and MLC error ranges were observed. For the two ionization devices, the sensitivity of the IQM was significantly better than that of the Farmer chamber (P < 0.01) while both devices had good linearly correlation between the cumulative signal difference and the magnitude of MLC errors. The pass rates decreased as the magnitude of the MLC error increased for both Delta4 and 2D-array. However, the small MLC error for small aperture sizes, such as for lung SBRT, could not be detected using the loosest gamma criteria (3%/3 mm). Our results indicate that DD could be more useful than gamma analysis for daily MLC QA, and that a large-area ionization chamber has a greater advantage for detecting systematic MLC error because of the large sensitive volume, while the other devices could not detect this error for some cases with a small range of MLC error. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  1. Calibration and quality assurance for rounded leaf-end MLC systems

    International Nuclear Information System (INIS)

    Graves, Maria N.; Thompson, Antoinette V.; Martel, Mary K.; McShan, Daniel L.; Fraass, Benedick A.

    2001-01-01

    Multileaf collimator (MLC) systems are available on most commercial linear accelerators, and many of these MLC systems utilize a design with rounded leaf ends and linear motion of the leaves. In this kind of system, the agreement between the digital MLC position readouts and the light field or radiation field edges must be achieved with software, since the leaves do not move in a focused motion like that used for most collimator jaw systems. In this work we address a number of the calibration and quality assurance issues associated with the acceptance, commissioning, and routine clinical use of this type of MLC system. These issues are particularly important for MLCs used for various types of intensity modulated radiation therapy (IMRT) and small, conformal fields. For rounded leaf end MLCs, it is generally not possible to make both the light and radiation field edges agree with the digital readout, so differences between the two kinds of calibrations are illustrated in this work using one vendor's MLC system. It is increasingly critical that the MLC leaf calibration be very consistent with the radiation field edges, so in this work a methodology for performing accurate radiation field size calibration is discussed. A system external to the vendor's MLC control system is used to correct or handle limitations in the MLC control system. When such a system of corrections is utilized, it is found that the MLC radiation field size can be defined with an accuracy of approximately 0.3 mm, much more accurate than most vendor's specifications for MLC accuracy. Quality assurance testing for such a calibration correction system is also demonstrated

  2. SU-E-T-205: MLC Predictive Maintenance Using Statistical Process Control Analysis.

    Science.gov (United States)

    Able, C; Hampton, C; Baydush, A; Bright, M

    2012-06-01

    MLC failure increases accelerator downtime and negatively affects the clinic treatment delivery schedule. This study investigates the use of Statistical Process Control (SPC), a modern quality control methodology, to retrospectively evaluate MLC performance data thereby predicting the impending failure of individual MLC leaves. SPC, a methodology which detects exceptional variability in a process, was used to analyze MLC leaf velocity data. A MLC velocity test is performed weekly on all leaves during morning QA. The leaves sweep 15 cm across the radiation field with the gantry pointing down. The leaf speed is analyzed from the generated dynalog file using quality assurance software. MLC leaf speeds in which a known motor failure occurred (8) and those in which no motor replacement was performed (11) were retrospectively evaluated for a 71 week period. SPC individual and moving range (I/MR) charts were used in the analysis. The I/MR chart limits were calculated using the first twenty weeks of data and set at 3 standard deviations from the mean. The MLCs in which a motor failure occurred followed two general trends: (a) no data indicating a change in leaf speed prior to failure (5 of 8) and (b) a series of data points exceeding the limit prior to motor failure (3 of 8). I/MR charts for a high percentage (8 of 11) of the non-replaced MLC motors indicated that only a single point exceeded the limit. These single point excesses were deemed false positives. SPC analysis using MLC performance data may be helpful in detecting a significant percentage of impending failures of MLC motors. The ability to detect MLC failure may depend on the method of failure (i.e. gradual or catastrophic). Further study is needed to determine if increasing the sampling frequency could increase reliability. Project was support by a grant from Varian Medical Systems, Inc. © 2012 American Association of Physicists in Medicine.

  3. Effect of interleukin-2 and methylprednisolone on in vitro transformation of uremic lymphocytes

    DEFF Research Database (Denmark)

    Langhoff, E; Ladefoged, J; Ødum, Niels

    1986-01-01

    The functional relationship in vitro between mitogen-induced lymphocyte transformation, lymphocyte response to interleukin-2 (IL-2) and steroid, and production of IL-2 was examined in patients with chronic renal failure on hemodialysis (HD) or on continuous ambulatory peritoneal dialysis (CAPD......). The lymphocyte responses to optimal stimulation with phytohemagglutinin, concanavalin A, and pokeweed mitogen were depressed in lymphocyte cultures from HD patients, while CAPD lymphocyte cultures responded normally. However, at suboptimal phytohemagglutinin stimulation both CAPD lymphocyte and HD lymphocyte...... responses were subnormal. Uremic lymphocyte cultures were more sensitive to the immunosuppressive effect of methylprednisolone. Addition of IL-2 normalized the phytohemagglutinin responses of suboptimally stimulated CAPD lymphocyte cultures and clearly improved the mitogen responses of the HD lymphocyte...

  4. Use of high dose X-irradiation to block back stimulation in the MLC reaction

    International Nuclear Information System (INIS)

    Sasazuki, T.; McMichael, A.; Radvany, R.; Payne, R.; McDevitt, H.

    1976-01-01

    Paradoxical stimulation, ''back stimulation'' was observed in MLR (mixed lymphocyte culture reaction) in both family and population studies. This is one of the major problems in obtaining clear cut-off points for stimulation and non-stimulation in MLR using LD (lymphocyte defined) homozygous typing cells. The ability to provoke back stimulation was found to be different among LD homozygous typing cells. The presence of nonspecific blastogenic factors in supernatant from mixed culture of LD homozygous and heterozygous cells, which might be responsible for back stimulation, was confirmed. It was clearly shown that irradiation of LD homozygous typing cells with 6,000 rads instead of the widely used 3,000 rads can greatly reduce or eliminate this back stimulation without introducing any false non-stimulation. (author)

  5. The beta1 subunit of the Na,K-ATPase pump interacts with megalencephalic leucoencephalopathy with subcortical cysts protein 1 (MLC1) in brain astrocytes: new insights into MLC pathogenesis.

    Science.gov (United States)

    Brignone, Maria S; Lanciotti, Angela; Macioce, Pompeo; Macchia, Gianfranco; Gaetani, Matteo; Aloisi, Francesca; Petrucci, Tamara C; Ambrosini, Elena

    2011-01-01

    Megalencephalic leucoencephalopathy with subcortical cysts (MLC) is a rare congenital leucodystrophy caused by mutations in MLC1, a membrane protein of unknown function. MLC1 expression in astrocyte end-feet contacting blood vessels and meninges, along with brain swelling, fluid cysts and myelin vacuolation observed in MLC patients, suggests a possible role for MLC1 in the regulation of fluid and ion homeostasis and cellular volume changes. To identify MLC1 direct interactors and dissect the molecular pathways in which MLC1 is involved, we used NH2-MLC1 domain as a bait to screen a human brain library in a yeast two-hybrid assay. We identified the β1 subunit of the Na,K-ATPase pump as one of the interacting clones and confirmed it by pull-downs, co-fractionation assays and immunofluorescence stainings in human and rat astrocytes in vitro and in brain tissue. By performing ouabain-affinity chromatography on astrocyte and brain extracts, we isolated MLC1 and the whole Na,K-ATPase enzyme in a multiprotein complex that included Kir4.1, syntrophin and dystrobrevin. Because Na,K-ATPase is involved in intracellular osmotic control and volume regulation, we investigated the effect of hypo-osmotic stress on MLC1/Na,K-ATPase relationship in astrocytes. We found that hypo-osmotic conditions increased MLC1 membrane expression and favoured MLC1/Na,K-ATPase-β1 association. Moreover, hypo-osmosis induced astrocyte swelling and the reversible formation of endosome-derived vacuoles, where the two proteins co-localized. These data suggest that through its interaction with Na,K-ATPase, MLC1 is involved in the control of intracellular osmotic conditions and volume regulation in astrocytes, opening new perspectives for understanding the pathological mechanisms of MLC disease.

  6. Live vaccinia-rabies virus recombinants, but not an inactivated rabies virus cell culture vaccine, protect B-lymphocyte-deficient A/WySnJ mice against rabies: considerations of recombinant defective poxviruses for rabies immunization of immunocompromised individuals.

    Science.gov (United States)

    Lodmell, Donald L; Esposito, Joseph J; Ewalt, Larry C

    2004-09-03

    Presently, commercially available cell culture rabies vaccines for humans and animals consist of the five inactivated rabies virus proteins. The vaccines elicit a CD4+ helper T-cell response and a humoral B-cell response against the viral glycoprotein (G) resulting in the production of virus neutralizing antibody. Antibody against the viral nucleoprotein (N) is also present, but the mechanism(s) of its protection is unclear. HIV-infected individuals with low CD4+ T-lymphocyte counts and individuals undergoing treatment with immunosuppressive drugs have an impaired neutralizing antibody response after pre- and post-exposure immunization with rabies cell culture vaccines. Here we show the efficacy of live vaccinia-rabies virus recombinants, but not a cell culture vaccine consisting of inactivated rabies virus, to elicit elevated levels of neutralizing antibody in B-lymphocyte deficient A/WySnJ mice. The cell culture vaccine also failed to protect the mice, whereas a single immunization of a vaccinia recombinant expressing the rabies virus G or co-expressing G and N equally protected the mice up to 18 months after vaccination. The data suggest that recombinant poxviruses expressing the rabies virus G, in particular replication defective poxviruses such as canarypox or MVA vaccinia virus that undergo abortive replication in non-avian cells, or the attenuated vaccinia virus NYVAC, should be evaluated as rabies vaccines in immunocompromised individuals.

  7. Implementation of a Quality Control using portal imaging dynamic MLC; Implementacion de un programa de control de calidad de MLC dinamico mediante imagen portal

    Energy Technology Data Exchange (ETDEWEB)

    Sanz Freire, C. J.; Vazquez Galinanes, A.; Collado Chamorro, P. M.; Diaz Pascual, V.; Gomez Amez, J.; Sanchez Martinez, S.; Ossola Lentati, G. A

    2011-07-01

    The precision in the correct beam irradiation in the treatment of highly modulated Intensity Modulated Radiation Therapy (IMRT) depends largely on the characteristics and behavior of the multi leaf collimator (MLC). Quality control (QC) of this element is essential to ensure proper delivery of the beams calculated. It is important to know the absolute position of each sheet, the motion characteristics of each behavior and stability. Among the numerous methods for carrying out the QC MLC, the use of portal imaging is a practical and high resolution. This paper describes the development of a quality control program based dynamic MLC portal image, self-developed software that enables analysis and the results of two years experience following the implementation of IMRT treatments at our center. (Author)

  8. Real-time dynamic MLC tracking for inversely optimized arc radiotherapy

    DEFF Research Database (Denmark)

    Falk, Marianne; af Rosenschöld, Per Munck; Keall, Paul

    2010-01-01

    Motion compensation with MLC tracking was tested for inversely optimized arc radiotherapy with special attention to the impact of the size of the target displacements and the angle of the leaf trajectory.......Motion compensation with MLC tracking was tested for inversely optimized arc radiotherapy with special attention to the impact of the size of the target displacements and the angle of the leaf trajectory....

  9. An independent dose calculation algorithm for MLC-based stereotactic radiotherapy

    International Nuclear Information System (INIS)

    Lorenz, Friedlieb; Killoran, Joseph H.; Wenz, Frederik; Zygmanski, Piotr

    2007-01-01

    We have developed an algorithm to calculate dose in a homogeneous phantom for radiotherapy fields defined by multi-leaf collimator (MLC) for both static and dynamic MLC delivery. The algorithm was developed to supplement the dose algorithms of the commercial treatment planning systems (TPS). The motivation for this work is to provide an independent dose calculation primarily for quality assurance (QA) and secondarily for the development of static MLC field based inverse planning. The dose calculation utilizes a pencil-beam kernel. However, an explicit analytical integration results in a closed form for rectangular-shaped beamlets, defined by single leaf pairs. This approach reduces spatial integration to summation, and leads to a simple method of determination of model parameters. The total dose for any static or dynamic MLC field is obtained by summing over all individual rectangles from each segment which offers faster speed to calculate two-dimensional dose distributions at any depth in the phantom. Standard beam data used in the commissioning of the TPS was used as input data for the algorithm. The calculated results were compared with the TPS and measurements for static and dynamic MLC. The agreement was very good (<2.5%) for all tested cases except for very small static MLC sizes of 0.6 cmx0.6 cm (<6%) and some ion chamber measurements in a high gradient region (<4.4%). This finding enables us to use the algorithm for routine QA as well as for research developments

  10. Detailed analysis of latencies in image-based dynamic MLC tracking

    International Nuclear Information System (INIS)

    Poulsen, Per Rugaard; Cho, Byungchul; Sawant, Amit; Ruan, Dan; Keall, Paul J.

    2010-01-01

    Purpose: Previous measurements of the accuracy of image-based real-time dynamic multileaf collimator (DMLC) tracking show that the major contributor to errors is latency, i.e., the delay between target motion and MLC response. Therefore the purpose of this work was to develop a method for detailed analysis of latency contributions during image-based DMLC tracking. Methods: A prototype DMLC tracking system integrated with a linear accelerator was used for tracking a phantom with an embedded fiducial marker during treatment delivery. The phantom performed a sinusoidal motion. Real-time target localization was based on x-ray images acquired either with a portal imager or a kV imager mounted orthogonal to the treatment beam. Each image was stored in a file on the imaging workstation. A marker segmentation program opened the image file, determined the marker position in the image, and transferred it to the DMLC tracking program. This program estimated the three-dimensional target position by a single-imager method and adjusted the MLC aperture to the target position. Imaging intervals ΔT image from 150 to 1000 ms were investigated for both kV and MV imaging. After the experiments, the recorded images were synchronized with MLC log files generated by the MLC controller and tracking log files generated by the tracking program. This synchronization allowed temporal analysis of the information flow for each individual image from acquisition to completed MLC adjustment. The synchronization also allowed investigation of the MLC adjustment dynamics on a considerably finer time scale than the 50 ms time resolution of the MLC log files. Results: For ΔT image =150 ms, the total time from image acquisition to completed MLC adjustment was 380±9 ms for MV and 420±12 ms for kV images. The main part of this time was from image acquisition to completed image file writing (272 ms for MV and 309 ms for kV). Image file opening (38 ms), marker segmentation (4 ms), MLC position

  11. Detailed analysis of latencies in image-based dynamic MLC tracking

    Energy Technology Data Exchange (ETDEWEB)

    Poulsen, Per Rugaard; Cho, Byungchul; Sawant, Amit; Ruan, Dan; Keall, Paul J. [Department of Radiation Oncology, Stanford University, Stanford, California 94305 and Department of Oncology and Department of Medical Physics, Aarhus University Hospital, 8000 Aarhus (Denmark); Department of Radiation Oncology, Stanford University, Stanford, California 94305 and Department of Radiation Oncology, Asan Medical Center, Seoul 138-736 (Korea, Republic of); Department of Radiation Oncology, Stanford University, Stanford, California 94305 (United States)

    2010-09-15

    Purpose: Previous measurements of the accuracy of image-based real-time dynamic multileaf collimator (DMLC) tracking show that the major contributor to errors is latency, i.e., the delay between target motion and MLC response. Therefore the purpose of this work was to develop a method for detailed analysis of latency contributions during image-based DMLC tracking. Methods: A prototype DMLC tracking system integrated with a linear accelerator was used for tracking a phantom with an embedded fiducial marker during treatment delivery. The phantom performed a sinusoidal motion. Real-time target localization was based on x-ray images acquired either with a portal imager or a kV imager mounted orthogonal to the treatment beam. Each image was stored in a file on the imaging workstation. A marker segmentation program opened the image file, determined the marker position in the image, and transferred it to the DMLC tracking program. This program estimated the three-dimensional target position by a single-imager method and adjusted the MLC aperture to the target position. Imaging intervals {Delta}T{sub image} from 150 to 1000 ms were investigated for both kV and MV imaging. After the experiments, the recorded images were synchronized with MLC log files generated by the MLC controller and tracking log files generated by the tracking program. This synchronization allowed temporal analysis of the information flow for each individual image from acquisition to completed MLC adjustment. The synchronization also allowed investigation of the MLC adjustment dynamics on a considerably finer time scale than the 50 ms time resolution of the MLC log files. Results: For {Delta}T{sub image}=150 ms, the total time from image acquisition to completed MLC adjustment was 380{+-}9 ms for MV and 420{+-}12 ms for kV images. The main part of this time was from image acquisition to completed image file writing (272 ms for MV and 309 ms for kV). Image file opening (38 ms), marker segmentation (4 ms

  12. Motion management during IMAT treatment of mobile lung tumors-A comparison of MLC tracking and gated delivery

    DEFF Research Database (Denmark)

    Falk, Marianne; Pommer, Tobias; Keall, Paul

    2014-01-01

    Purpose:To compare real-time dynamic multileaf collimator (MLC) tracking, respiratory amplitude and phase gating, and no compensation for intrafraction motion management during intensity modulated arc therapy (IMAT). Methods: Motion management with MLC tracking and gating was evaluated for four...... tracking reduced the effects of the target movements, although the gated delivery showed a better dosimetric accuracy and enabled a larger reduction of the margins in some cases. MLC tracking did not prolong the treatment time compared to delivery with no motion compensation while gating had a considerably...... of the dosimetric error contributions showed that the gated delivery mainly had errors in target localization, while MLC tracking also had contributions from MLC leaf fitting and leaf adjustment. The average treatment time was about three times longer with gating compared to delivery with MLC tracking (that did...

  13. Chronic lymphocytic leukemia (CLL)

    Science.gov (United States)

    ... is used for painful and enlarged lymph nodes. Blood transfusions or platelet transfusions may be required if blood ... unexplained fatigue, bruising, excessive sweating, or weight loss. Alternative ... Leukemia - chronic lymphocytic (CLL); Blood cancer - chronic lymphocytic leukemia; Bone marrow cancer - chronic ...

  14. Dosimetric impact of systematic MLC positional errors on step and shoot IMRT for prostate cancer: a planning study

    International Nuclear Information System (INIS)

    Ung, N.M.; Wee, L.; Harper, C.S.

    2010-01-01

    Full text: The positional accuracy of multi leaf collimators (MLC) is crucial in ensuring precise delivery of intensity-modulated radiotherapy (IMRT). The aim of this planning study was to investigate the dosimetric impact of systematic MLC errors on step and shoot IMRT of prostate cancer. Twelve MLC leaf banks perturbations were introduced to six prostate IMRT treatment plans to simulate MLC systematic errors. Dose volume histograms (OYHs) were generated for the extraction of dose endpoint parameters. Plans were evaluated in terms of changes to the defined endpoint dose parameters, conformity index (CI) and healthy tissue avoidance (HTA) to planning target volume (PTY), rectum and bladder. Negative perturbations of MLC had been found to produce greater changes to endpoint dose parameters than positive perturbations of MLC (p < 0.05). Negative and positive synchronized MLC perturbations of I mm resulted in median changes of -2.32 and 1.78%, respectively to 095% of PTY whereas asynchronized MLC perturbations of the same direction and magnitude resulted in median changes of 1.18 and 0.90%, respectively. Doses to rectum were generally more sensitive to systematic MLC errors compared to bladder. Synchronized MLC perturbations of I mm resulted in median changes of endpoint dose parameters to both rectum and bladder from about I to 3%. Maximum reduction of -4.44 and -7.29% were recorded for CI and HTA, respectively, due to synchronized MLC perturbation of I mm. In summary, MLC errors resulted in measurable amount of dose changes to PTY and surrounding critical structures in prostate LMRT. (author)

  15. SU-E-T-195: Gantry Angle Dependency of MLC Leaf Position Error

    Energy Technology Data Exchange (ETDEWEB)

    Ju, S; Hong, C; Kim, M; Chung, K; Kim, J; Han, Y; Ahn, S; Chung, S; Shin, E; Shin, J; Kim, H; Kim, D; Choi, D [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2014-06-01

    Purpose: The aim of this study was to investigate the gantry angle dependency of the multileaf collimator (MLC) leaf position error. Methods: An automatic MLC quality assurance system (AutoMLCQA) was developed to evaluate the gantry angle dependency of the MLC leaf position error using an electronic portal imaging device (EPID). To eliminate the EPID position error due to gantry rotation, we designed a reference maker (RM) that could be inserted into the wedge mount. After setting up the EPID, a reference image was taken of the RM using an open field. Next, an EPID-based picket-fence test (PFT) was performed without the RM. These procedures were repeated at every 45° intervals of the gantry angle. A total of eight reference images and PFT image sets were analyzed using in-house software. The average MLC leaf position error was calculated at five pickets (-10, -5, 0, 5, and 10 cm) in accordance with general PFT guidelines using in-house software. This test was carried out for four linear accelerators. Results: The average MLC leaf position errors were within the set criterion of <1 mm (actual errors ranged from -0.7 to 0.8 mm) for all gantry angles, but significant gantry angle dependency was observed in all machines. The error was smaller at a gantry angle of 0° but increased toward the positive direction with gantry angle increments in the clockwise direction. The error reached a maximum value at a gantry angle of 90° and then gradually decreased until 180°. In the counter-clockwise rotation of the gantry, the same pattern of error was observed but the error increased in the negative direction. Conclusion: The AutoMLCQA system was useful to evaluate the MLC leaf position error for various gantry angles without the EPID position error. The Gantry angle dependency should be considered during MLC leaf position error analysis.

  16. Dose domain regularization of MLC leaf patterns for highly complex IMRT plans

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dan; Yu, Victoria Y.; Ruan, Dan; Cao, Minsong; Low, Daniel A.; Sheng, Ke, E-mail: ksheng@mednet.ucla.edu [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California 90095 (United States); O’Connor, Daniel [Department of Mathematics, University of California Los Angeles, Los Angeles, California 90095 (United States)

    2015-04-15

    Purpose: The advent of automated beam orientation and fluence optimization enables more complex intensity modulated radiation therapy (IMRT) planning using an increasing number of fields to exploit the expanded solution space. This has created a challenge in converting complex fluences to robust multileaf collimator (MLC) segments for delivery. A novel method to regularize the fluence map and simplify MLC segments is introduced to maximize delivery efficiency, accuracy, and plan quality. Methods: In this work, we implemented a novel approach to regularize optimized fluences in the dose domain. The treatment planning problem was formulated in an optimization framework to minimize the segmentation-induced dose distribution degradation subject to a total variation regularization to encourage piecewise smoothness in fluence maps. The optimization problem was solved using a first-order primal-dual algorithm known as the Chambolle-Pock algorithm. Plans for 2 GBM, 2 head and neck, and 2 lung patients were created using 20 automatically selected and optimized noncoplanar beams. The fluence was first regularized using Chambolle-Pock and then stratified into equal steps, and the MLC segments were calculated using a previously described level reducing method. Isolated apertures with sizes smaller than preset thresholds of 1–3 bixels, which are square units of an IMRT fluence map from MLC discretization, were removed from the MLC segments. Performance of the dose domain regularized (DDR) fluences was compared to direct stratification and direct MLC segmentation (DMS) of the fluences using level reduction without dose domain fluence regularization. Results: For all six cases, the DDR method increased the average planning target volume dose homogeneity (D95/D5) from 0.814 to 0.878 while maintaining equivalent dose to organs at risk (OARs). Regularized fluences were more robust to MLC sequencing, particularly to the stratification and small aperture removal. The maximum and

  17. State-Transition-Aware Spilling Heuristic for MLC STT-RAM-Based Registers

    Directory of Open Access Journals (Sweden)

    Yuanhui Ni

    2017-01-01

    Full Text Available Multilevel Cell Spin-Transfer Torque Random Access Memory (MLC STT-RAM is a promising nonvolatile memory technology to build registers for its natural immunity to electromagnetic radiation in rad-hard space environment. Unlike traditional SRAM-based registers, MLC STT-RAM exhibits unbalanced write state transitions due to the fact that the magnetization directions of hard and soft domains cannot be flipped independently. This feature leads to nonuniform costs of write states in terms of latency and energy. However, current SRAM-targeting register allocations do not have a clear understanding of the impact of the different write state-transition costs. As a result, those approaches heuristically select variables to be spilled without considering the spilling priority imposed by MLC STT-RAM. Aiming to address this limitation, this paper proposes a state-transition-aware spilling cost minimization (SSCM policy, to save power when MLC STT-RAM is employed in register design. Specifically, the spilling cost model is first constructed according to the linear combination of different state-transition frequencies. Directed by the proposed cost model, the compiler picks up spilling candidates to achieve lower power and higher performance. Experimental results show that the proposed SSCM technique can save energy by 19.4% and improve the lifetime by 23.2% of MLC STT-RAM-based register design.

  18. Radiation effects on lymphocytes

    International Nuclear Information System (INIS)

    Roser, B.

    1976-01-01

    This review of the ontogeny of lymphocyte populations concentrates on sites of production, rates of production, and the factors governing the differentiation and longevity of the various lymphocyte pools. The physiology of the lymphocyte pools is described with particular emphasis on recirculation from blood to lymph through lymphoid tissues. The separate routes of recirculation of both thymus-derived and nonthymus-derived lymphocytes and the possible anatomical sites and mechanisms of lymphocyte cooperation are discussed. Radiation effects on lymphocyte populations are divided into two sections. First, the effects of whole-body irradiation on the total lymphocyte pools are discussed including the differential effects of irradiation on T lymphocytes, B lymphocytes, lymphoblasts, and plasma cells. The differential sensitivity of various types of immune response is correlated, where possible, with the differential sensitivity of the lymphocyte types involved. Second, experimental attempts to selectively deplete discrete subpopulations of the total lymphocyte pools, e.g., recirculating cells, are briefly discussed with particular emphasis on studies on the effects of the localization of radionuclides in lymphoid tissue

  19. GENERATION OF CYTOTOXIC LYMPHOCYTES IN MIXED LYMPHOCYTE REACTIONS

    Science.gov (United States)

    Forman, James; Möller, Göran

    1973-01-01

    Generation of cytotoxic effector cells by a unidirectional mixed lymphocyte reaction (MLR) in the mouse H-2 system was studied using labeled YAC (H-2a) leukemia cells as targets. The responding effector cell displayed a specific cytotoxic effect against target cells of the same H-2 genotype as the stimulating cell population. Killing of syngeneic H-2 cells was not observed, even when the labeled target cells were "innocent bystanders" in cultures where specific target cells were reintroduced. Similar results were found with spleen cells taken from mice sensitized in vivo 7 days earlier. The effector cell was not an adherent cell and was not activated by supernatants from MLR. The supernatants were not cytotoxic by themselves. When concanavalin A or phytohemagglutinin was added to the cytotoxic test system, target and effector cells were agglutinated. Under these conditions, killing of H-2a target cells was observed in mixed cultures where H-2a lymphocytes were also the effector cells. These findings indicate that specifically activated, probably thymus-derived lymphocytes, can kill nonspecifically once they have been activated and providing there is close contact between effector and target cells. Thus, specificity of T cell killing appears to be restricted to recognition and subsequent binding to the targets, the actual effector phase being nonspecific. PMID:4269560

  20. Dosimetric impact of systematic MLC positional errors on step and shoot IMRT for prostate cancer: a planning study

    International Nuclear Information System (INIS)

    Ung, N.M.; Harper, C.S.; Wee, L.

    2011-01-01

    Full text: The positional accuracy of multileaf collimators (MLC) is crucial in ensuring precise delivery of intensity-modulated radiotherapy (IMRT). The aim of this planning study was to investigate the dosimetric impact of systematic MLC positional errors on step and shoot IMRT of prostate cancer. A total of 12 perturbations of MLC leaf banks were introduced to six prostate IMRT treatment plans to simulate MLC systematic positional errors. Dose volume histograms (DVHs) were generated for the extraction of dose endpoint parameters. Plans were evaluated in terms of changes to the defined endpoint dose parameters, conformity index (CI) and healthy tissue avoidance (HTA) to planning target volume (PTV), rectum and bladder. Negative perturbations of MLC had been found to produce greater changes to endpoint dose parameters than positive perturbations of MLC (p 9 5 of -1.2 and 0.9% respectively. Negative and positive synchronised MLC perturbations of I mm in one direction resulted in median changes in D 9 5 of -2.3 and 1.8% respectively. Doses to rectum were generally more sensitive to systematic MLC en-ors compared to bladder (p < 0.01). Negative and positive synchronised MLC perturbations of I mm in one direction resulted in median changes in endpoint dose parameters of rectum and bladder from 1.0 to 2.5%. Maximum reduction of -4.4 and -7.3% were recorded for conformity index (CI) and healthy tissue avoidance (HT A) respectively due to synchronised MLC perturbation of 1 mm. MLC errors resulted in dosimetric changes in IMRT plans for prostate. (author)

  1. Fast motion-including dose error reconstruction for VMAT with and without MLC tracking

    DEFF Research Database (Denmark)

    Ravkilde, Thomas; Keall, Paul J.; Grau, Cai

    2014-01-01

    of the algorithm for reconstruction of dose and motion-induced dose errors throughout the tracking and non-tracking beam deliveries was quantified. Doses were reconstructed with a mean dose difference relative to the measurements of -0.5% (5.5% standard deviation) for cumulative dose. More importantly, the root...... validate a simple model for fast motion-including dose error reconstruction applicable to intrafractional QA of MLC tracking treatments of moving targets. MLC tracking experiments were performed on a standard linear accelerator with prototype MLC tracking software guided by an electromagnetic transponder......-mean-square deviation between reconstructed and measured motion-induced 3%/3 mm γ failure rates (dose error) was 2.6%. The mean computation time for each calculation of dose and dose error was 295 ms. The motion-including dose reconstruction allows accurate temporal and spatial pinpointing of errors in absorbed dose...

  2. SU-E-T-784: Using MLC Log Files for Daily IMRT Delivery Verification

    Energy Technology Data Exchange (ETDEWEB)

    Stathakis, S; Defoor, D; Linden, P; Kirby, N; Papanikolaou, N [University of Texas HSC SA, San Antonio, TX (United States)

    2015-06-15

    Purpose: To verify daily intensity modulated radiation therapy (IMRT) treatments using multi-leaf collimator (MLC) log files. Methods: The MLC log files from a NovalisTX Varian linear accelerator were used in this study. The MLC files were recorded daily for all patients undergoing IMRT or volumetric modulated arc therapy (VMAT). The first record of each patient was used as reference and all records for subsequent days were compared against the reference. An in house MATLAB software code was used for the comparisons. Each MLC log file was converted to a fluence map (FM) and a gamma index (γ) analysis was used for the evaluation of each daily delivery for every patient. The tolerance for the gamma index was set to 2% dose difference and 2mm distance to agreement while points with signal of 10% or lower of the maximum value were excluded from the comparisons. Results: The γ between each of the reference FMs and the consecutive daily fraction FMs had an average value of 99.1% (ranged from 98.2 to 100.0%). The FM images were reconstructed at various resolutions in order to study the effect of the resolution on the γ and at the same time reduce the time for processing the images. We found that the comparison of images with the highest resolution (768×1024) yielded on average a lower γ (99.1%) than the ones with low resolution (192×256) (γ 99.5%). Conclusion: We developed an in-house software that allows us to monitor the quality of daily IMRT and VMAT treatment deliveries using information from the MLC log files of the linear accelerator. The information can be analyzed and evaluated as early as after the completion of each daily treatment. Such tool can be valuable to assess the effect of MLC positioning on plan quality, especially in the context of adaptive radiotherapy.

  3. Multiple linear combination (MLC) regression tests for common variants adapted to linkage disequilibrium structure.

    Science.gov (United States)

    Yoo, Yun Joo; Sun, Lei; Poirier, Julia G; Paterson, Andrew D; Bull, Shelley B

    2017-02-01

    By jointly analyzing multiple variants within a gene, instead of one at a time, gene-based multiple regression can improve power, robustness, and interpretation in genetic association analysis. We investigate multiple linear combination (MLC) test statistics for analysis of common variants under realistic trait models with linkage disequilibrium (LD) based on HapMap Asian haplotypes. MLC is a directional test that exploits LD structure in a gene to construct clusters of closely correlated variants recoded such that the majority of pairwise correlations are positive. It combines variant effects within the same cluster linearly, and aggregates cluster-specific effects in a quadratic sum of squares and cross-products, producing a test statistic with reduced degrees of freedom (df) equal to the number of clusters. By simulation studies of 1000 genes from across the genome, we demonstrate that MLC is a well-powered and robust choice among existing methods across a broad range of gene structures. Compared to minimum P-value, variance-component, and principal-component methods, the mean power of MLC is never much lower than that of other methods, and can be higher, particularly with multiple causal variants. Moreover, the variation in gene-specific MLC test size and power across 1000 genes is less than that of other methods, suggesting it is a complementary approach for discovery in genome-wide analysis. The cluster construction of the MLC test statistics helps reveal within-gene LD structure, allowing interpretation of clustered variants as haplotypic effects, while multiple regression helps to distinguish direct and indirect associations. © 2016 The Authors Genetic Epidemiology Published by Wiley Periodicals, Inc.

  4. The sensitivity of patient specific IMRT QC to systematic MLC leaf bank offset errors

    International Nuclear Information System (INIS)

    Rangel, Alejandra; Palte, Gesa; Dunscombe, Peter

    2010-01-01

    Purpose: Patient specific IMRT QC is performed routinely in many clinics as a safeguard against errors and inaccuracies which may be introduced during the complex planning, data transfer, and delivery phases of this type of treatment. The purpose of this work is to evaluate the feasibility of detecting systematic errors in MLC leaf bank position with patient specific checks. Methods: 9 head and neck (H and N) and 14 prostate IMRT beams were delivered using MLC files containing systematic offsets (±1 mm in two banks, ±0.5 mm in two banks, and 1 mm in one bank of leaves). The beams were measured using both MAPCHECK (Sun Nuclear Corp., Melbourne, FL) and the aS1000 electronic portal imaging device (Varian Medical Systems, Palo Alto, CA). Comparisons with calculated fields, without offsets, were made using commonly adopted criteria including absolute dose (AD) difference, relative dose difference, distance to agreement (DTA), and the gamma index. Results: The criteria most sensitive to systematic leaf bank offsets were the 3% AD, 3 mm DTA for MAPCHECK and the gamma index with 2% AD and 2 mm DTA for the EPID. The criterion based on the relative dose measurements was the least sensitive to MLC offsets. More highly modulated fields, i.e., H and N, showed greater changes in the percentage of passing points due to systematic MLC inaccuracy than prostate fields. Conclusions: None of the techniques or criteria tested is sufficiently sensitive, with the population of IMRT fields, to detect a systematic MLC offset at a clinically significant level on an individual field. Patient specific QC cannot, therefore, substitute for routine QC of the MLC itself.

  5. The sensitivity of patient specific IMRT QC to systematic MLC leaf bank offset errors

    Energy Technology Data Exchange (ETDEWEB)

    Rangel, Alejandra; Palte, Gesa; Dunscombe, Peter [Department of Medical Physics, Tom Baker Cancer Centre, 1331-29 Street NW, Calgary, Alberta T2N 4N2, Canada and Department of Physics and Astronomy, University of Calgary, 2500 University Drive North West, Calgary, Alberta T2N 1N4 (Canada); Department of Medical Physics, Tom Baker Cancer Centre, 1331-29 Street NW, Calgary, Alberta T2N 4N2 (Canada); Department of Medical Physics, Tom Baker Cancer Centre, 1331-29 Street NW, Calgary, Alberta T2N 4N2 (Canada); Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4 (Canada) and Department of Oncology, Tom Baker Cancer Centre, 1331-29 Street NW, Calgary, Alberta T2N 4N2 (Canada)

    2010-07-15

    Purpose: Patient specific IMRT QC is performed routinely in many clinics as a safeguard against errors and inaccuracies which may be introduced during the complex planning, data transfer, and delivery phases of this type of treatment. The purpose of this work is to evaluate the feasibility of detecting systematic errors in MLC leaf bank position with patient specific checks. Methods: 9 head and neck (H and N) and 14 prostate IMRT beams were delivered using MLC files containing systematic offsets ({+-}1 mm in two banks, {+-}0.5 mm in two banks, and 1 mm in one bank of leaves). The beams were measured using both MAPCHECK (Sun Nuclear Corp., Melbourne, FL) and the aS1000 electronic portal imaging device (Varian Medical Systems, Palo Alto, CA). Comparisons with calculated fields, without offsets, were made using commonly adopted criteria including absolute dose (AD) difference, relative dose difference, distance to agreement (DTA), and the gamma index. Results: The criteria most sensitive to systematic leaf bank offsets were the 3% AD, 3 mm DTA for MAPCHECK and the gamma index with 2% AD and 2 mm DTA for the EPID. The criterion based on the relative dose measurements was the least sensitive to MLC offsets. More highly modulated fields, i.e., H and N, showed greater changes in the percentage of passing points due to systematic MLC inaccuracy than prostate fields. Conclusions: None of the techniques or criteria tested is sufficiently sensitive, with the population of IMRT fields, to detect a systematic MLC offset at a clinically significant level on an individual field. Patient specific QC cannot, therefore, substitute for routine QC of the MLC itself.

  6. SU-F-T-289: MLC Fluence Sonogram Based Delivery Quality Assurance for Bilateral Breast Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Thiyagarajan, Rajesh; Karrthick, KP; Kataria, Tejinder; Mahendran, Ramu; Selvan, Tamil; Duraikannu, Palani [Division of Radiation Oncology, Medanta The Medicity, Gurgaon, Haryana (India); Raj, Nambi [Department of Physics, School of Advanced sciences, VIT University, Vellore (India); Arunai, N

    2016-06-15

    Purpose: Performing DQA for Bilateral (B-L) breast tomotherapy is a challenging task due to the limitation of any commercially available detector array or film. Aim of this study is to perform DQA for B-L breast tomotherapy plan using MLC fluence sinogram. Methods: Treatment plan was generated on Tomotherapy system for B-L breast tumour. B-L breast targets were given 50.4 Gy prescribed over 28 fractions. Plan is generated with 6 MV photon beam & pitch was set to 0.3. As the width of the total target is 39 cm (left & right) length is 20 cm. DQA plan delivered without any phantom on the mega voltage computed tomography (MCVT) detector system. The pulses recorded by MVCT system were exported to the delivery analysis software (Tomotherapy Inc.) for reconstruction. The detector signals are reconstructed to a sonogram and converted to MLC fluence sonogram. The MLC fluence sinogram compared with the planned fluence sinogram. Also point dose measured with cheese phantom and ionization chamber to verify the absolute dose component Results: Planned fluence sinogram and reconstructed MLC fluence sinogram were compared using Gamma metric. MLC positional difference and intensity of the beamlet were used as parameters to evaluate gamma. 3 mm positional difference and 3% beamlet intensity difference were used set for gamma calculation. A total of 26784 non-zero beamlets were included in the analysis out of which 161 beamlets had gamma more than 1. The gamma passing rate found to be 99.4%. Point dose measurements were within 1.3% of the calculated dose. Conclusion: MLC fluence sinogram based delivery quality assurance performed for bilateral breast irradiation. This would be a suitable alternate for large volume targets like bilateral breast, Total body irradiation etc. However conventional method of DQA should be used to validate this method periodically.

  7. First evaluation of the feasibility of MLC tracking using ultrasound motion estimation

    Energy Technology Data Exchange (ETDEWEB)

    Fast, Martin F., E-mail: martin.fast@icr.ac.uk; O’Shea, Tuathan P., E-mail: tuathan.oshea@nhs.net; Nill, Simeon; Oelfke, Uwe; Harris, Emma J. [Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG (United Kingdom)

    2016-08-15

    Purpose: To quantify the performance of the Clarity ultrasound (US) imaging system (Elekta AB, Stockholm, Sweden) for real-time dynamic multileaf collimator (MLC) tracking. Methods: The Clarity calibration and quality assurance phantom was mounted on a motion platform moving with a periodic sine wave trajectory. The detected position of a 30 mm hypoechogenic sphere within the phantom was continuously reported via Clarity’s real-time streaming interface to an in-house tracking and delivery software and subsequently used to adapt the MLC aperture. A portal imager measured MV treatment field/MLC apertures and motion platform positions throughout each experiment to independently quantify system latency and geometric error. Based on the measured range of latency values, a prostate stereotactic body radiation therapy (SBRT) delivery was performed with three realistic motion trajectories. The dosimetric impact of system latency on MLC tracking was directly measured using a 3D dosimeter mounted on the motion platform. Results: For 2D US imaging, the overall system latency, including all delay times from the imaging and delivery chain, ranged from 392 to 424 ms depending on the lateral sector size. For 3D US imaging, the latency ranged from 566 to 1031 ms depending on the elevational sweep. The latency-corrected geometric root-mean squared error was below 0.75 mm (2D US) and below 1.75 mm (3D US). For the prostate SBRT delivery, the impact of a range of system latencies (400–1000 ms) on the MLC tracking performance was minimal in terms of gamma failure rate. Conclusions: Real-time MLC tracking based on a noninvasive US input is technologically feasible. Current system latencies are higher than those for x-ray imaging systems, but US can provide full volumetric image data and the impact of system latency was measured to be small for a prostate SBRT case when using a US-like motion input.

  8. First evaluation of the feasibility of MLC tracking using ultrasound motion estimation

    International Nuclear Information System (INIS)

    Fast, Martin F.; O’Shea, Tuathan P.; Nill, Simeon; Oelfke, Uwe; Harris, Emma J.

    2016-01-01

    Purpose: To quantify the performance of the Clarity ultrasound (US) imaging system (Elekta AB, Stockholm, Sweden) for real-time dynamic multileaf collimator (MLC) tracking. Methods: The Clarity calibration and quality assurance phantom was mounted on a motion platform moving with a periodic sine wave trajectory. The detected position of a 30 mm hypoechogenic sphere within the phantom was continuously reported via Clarity’s real-time streaming interface to an in-house tracking and delivery software and subsequently used to adapt the MLC aperture. A portal imager measured MV treatment field/MLC apertures and motion platform positions throughout each experiment to independently quantify system latency and geometric error. Based on the measured range of latency values, a prostate stereotactic body radiation therapy (SBRT) delivery was performed with three realistic motion trajectories. The dosimetric impact of system latency on MLC tracking was directly measured using a 3D dosimeter mounted on the motion platform. Results: For 2D US imaging, the overall system latency, including all delay times from the imaging and delivery chain, ranged from 392 to 424 ms depending on the lateral sector size. For 3D US imaging, the latency ranged from 566 to 1031 ms depending on the elevational sweep. The latency-corrected geometric root-mean squared error was below 0.75 mm (2D US) and below 1.75 mm (3D US). For the prostate SBRT delivery, the impact of a range of system latencies (400–1000 ms) on the MLC tracking performance was minimal in terms of gamma failure rate. Conclusions: Real-time MLC tracking based on a noninvasive US input is technologically feasible. Current system latencies are higher than those for x-ray imaging systems, but US can provide full volumetric image data and the impact of system latency was measured to be small for a prostate SBRT case when using a US-like motion input.

  9. Cell kinetic and radiosensitivity of PHA stimulated goat lymphocytes

    International Nuclear Information System (INIS)

    Debuyst, B.; Rosenthal, M.; Leonard, A.

    1982-01-01

    The harlequin-staining method has been used to study the cell kinetic of goat peripheral blood lymphocytes stimulated by phytohemagglutinin and to assess their radiosensitivity. At 48 h, the standardized culture time employed for human lymphocytes, 71% of the goat lymphocytes are in first mitosis, 23% are in second mitosis and 5% in third. Irradiation with 200 rads X-rays induces an average of 24,5 dicentric chromosomes per hundred cells in first mitosis [fr

  10. Evaluation of two methods of predicting MLC leaf positions using EPID measurements

    International Nuclear Information System (INIS)

    Parent, Laure; Seco, Joao; Evans, Phil M.; Dance, David R.; Fielding, Andrew

    2006-01-01

    In intensity modulated radiation treatments (IMRT), the position of the field edges and the modulation within the beam are often achieved with a multileaf collimator (MLC). During the MLC calibration process, due to the finite accuracy of leaf position measurements, a systematic error may be introduced to leaf positions. Thereafter leaf positions of the MLC depend on the systematic error introduced on each leaf during MLC calibration and on the accuracy of the leaf position control system (random errors). This study presents and evaluates two methods to predict the systematic errors on the leaf positions introduced during the MLC calibration. The two presented methods are based on a series of electronic portal imaging device (EPID) measurements. A comparison with film measurements showed that the EPID could be used to measure leaf positions without introducing any bias. The first method, referred to as the 'central leaf method', is based on the method currently used at this center for MLC leaf calibration. It mimics the manner in which leaf calibration parameters are specified in the MLC control system and consequently is also used by other centers. The second method, a new method proposed by the authors and referred to as the ''individual leaf method,'' involves the measurement of two positions for each leaf (-5 and +15 cm) and the interpolation and extrapolation from these two points to any other given position. The central leaf method and the individual leaf method predicted leaf positions at prescribed positions of -11, 0, 5, and 10 cm within 2.3 and 1.0 mm, respectively, with a standard deviation (SD) of 0.3 and 0.2 mm, respectively. The individual leaf method provided a better prediction of the leaf positions than the central leaf method. Reproducibility tests for leaf positions of -5 and +15 cm were performed. The reproducibility was within 0.4 mm on the same day and 0.4 mm six weeks later (1 SD). Measurements at gantry angles of 0 deg., 90 deg., and 270 deg

  11. Elimination of radiation-induced chromosomal damages in numan peripheral blood lymphocyte cultures. 1. The frequency of aberrations in the first and second mitosis

    International Nuclear Information System (INIS)

    Pyatkin, E.K.; Nugis, V.Yu.

    1981-01-01

    A comparative analysis of chromosomal aberrations in the first and second mitosis of cultivated human peripheral blood lymphocytes after gamma irradiation in vitro at 1-5 Gy doses has been made. Irradiated blood lymphocytes were incubated for 58 to 66 h at 37 deg with PGA and BDU (20 μg /ml). The first, second and third postradiation mitosises were identified using the distinguishing staining of sister chromatids. The share of the cells in the first mitosis fluctuated from 32 to 77 %, in the second - from 23 to 68 %, and the third - from 0 to 9 %. At all radiation doses significant differences in the frequency of the aberration cells passing the first and second mitosises were revealed as well as in the total number of chromosomal aberrations in all the cells. The frequency of pair fragments and dicentrics chromosomes in the first mitosis was on the average 1.6 and 2 times as high as in the second one, respectively. In the first mitosis almost all dicentric chromosomes occurred with accompanying pair fragments, and in the second mitosis the share of dicentric chromosomes without accompanying fragments was 25 to 50 %. The distribution of the dicentric chromosomes in the cells in the first and second mitosis did not differ from Poison distribution for the 2 to 5 Gy dose range

  12. Inhibition of DNA synthesis in cultured lymphocytes and tumor cells by extracts of betel nut, tobacco, and miang leaf, plant substances associated with cancer of the ororespiratory epithelium.

    Science.gov (United States)

    Yang, J A; Huber, S A; Lucas, Z J

    1979-12-01

    The high incidence of oropharyngeal, esophageal, and laryngeal cancers in certain parts of the world has been ascribed to conjugated tannins found in certain folk medicinal herbs. We extracted miang leaf and betel nut with phosphate-buffered saline (0.14 M NaCl, 0.15 M potassium phosphate buffer, pH 7.4) and found that the extracts inhibited [3H]thymidine incorporation by phytohemagglutinin-stimulated human lymphocytes and by rat mammary tumor and mouse L-cells in logarithmic growth. Pretreating the lymphocytes for 1 or 4 hr with the extracts inhibited phytohemagglutinin-induced thymidine incorporation 72 hr later. At concentrations of 2.5 volumes % or lower, miang and betel nut extracts inhibited thymidine incorporation by 40 to 98% without any apparent signs of toxicity as demonstrated by the 66Rb equilibrium assay. In addition, neither extract inhibited cytotoxicity of rat mammary tumor cells by immune syngeneic spleen cells. The molecular weights of the inhibitory factors were between 1,000 and 10,000 daltons as determined by ultrafiltration and were unaffected by boiling for 3 min or by treatment with alcohol and, therefore, are probably not proteins. This in vitro demonstration of inhibition of DNA synthesis by these plant extracts presumably enriched for conjugated tannins may relate to inhibition of growth of rats and chicks fed conjugated tanin-contaminated sorghum feed. The carcinogenic potential of either these extracts or conjugated tannins is not yet established.

  13. Biodistribution of radiolabeled lymphocytes

    International Nuclear Information System (INIS)

    Fawwaz, R.A.; Oluwole, S.; Wang, T.S.; Kuromoto, N.; Iga, C.; Hardy, M.A.; Alderson, P.O.

    1985-01-01

    Factors that might affect the biodistribution and clinical utility of radiolabeled lymphocytes were evaluated in experimental animals. Indium-111 (In-111) labeled lymphocytes obtained from peripheral blood, lymph node, or spleen were found in significant amounts in the lymphoid tissues of Lewis rats as early as 3 hours after infusion. A progressive increase in nodal activity with concomitant fall of activity in other organs followed, indicating active recirculation of the lymphocytes. In vitro irradiation of the In-111 labeled lymphocytes resulted in no detectable lymphocyte recirculation and/or reduced localization in lymphoid tissue. Splenectomized animals and those sensitized to an organ allograft before cell infusion showed increased activity in their bone marrow. These results suggest that the source of the injected cells, cell irradiation dose level and host sensitization should be considered when radiolabeled lymphocytes are being prepared for use in clinical diagnosis and therapy

  14. SU-F-T-650: The Comparison of Robotic Partial Breast Stereotactic Irradiation Using MLC Vs. Iris Cone

    Energy Technology Data Exchange (ETDEWEB)

    Ding, C; Timmerman, R; Jiang, S; Rahimi, A [UT Southwestern Medical Center, Dallas, TX (United States)

    2016-06-15

    Purpose: To evaluate the dosimetric impact on treatment planning for partial breast stereotactic irradiation using Cyberknife with MLC versus Iris Cone. Methods: Ten patients whom underwent lumpectomy for DCIS or stage I invasive non-lobular epithelial breast cancer were included in this study. All patients were previously treated on the Cyberknife using Iris cone with the prescription dose of 37.5Gy in 5 fractions covering at least 95% of PTV on our phase I SBRT 5 fraction partial breast irradiation trial. Retrospectively, treatment planning was performed and compared using the new Cyberknife M6 MLC system for each patient. Using the same contours and critical organ constraints for both MLC and Iris cone plans, the dose on target and critical organs were analyzed accordingly. Results: Dose to critical organs such as ipsilateral lung, contralateral lung, heart, skin, ipsilateral breast, and rib were analyzed, as well as conformity index and high dose spillage of the target area. In 9 of 10 patients, the MLC plans had less total ipsilateral breast volume encompassing the 50% prescription isodose (mean:22.3±8.2% MLC vs. 31.6±8.0 Iris, p=0.00014) .The MLC plans mean estimated treatment delivery time was significantly less than the Iris plans (51±3.9min vs. 56.2±9min, p=0.03) Both MLC and Iris cone plans were able to meet all dose constraints and there was no statistical difference between those dose constraints. Conclusion: Both MLC and Iris Cone can deliver conformal dose to a partial breast target and satisfy the dose constraints of critical organs. The new Cyberknife with MLC can deliver a more conformal dose in the lower dose region and spare more ipsilateral breast tissue to the 50% prescription isodose. The treatment time for partial breast SBRT plans was also reduced using MLC. Project receives research support from Accuray Inc.

  15. SU-C-BRB-02: Symmetric and Asymmetric MLC Based Lung Shielding and Dose Optimization During Translating Bed TBI

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, S; Kakakhel, MB [Pakistan Institute of Engineering & Applied Sciences (PIEAS), Islamabad (Pakistan); Ahmed, SBS; Hussain, A [Aga Khan University Hospital (AKUH), Karachi (Pakistan)

    2015-06-15

    Purpose: The primary aim was to introduce a dose optimization method for translating bed total body irradiation technique that ensures lung shielding dynamically. Symmetric and asymmetric dynamic MLC apertures were employed for this purpose. Methods: The MLC aperture sizes were defined based on the radiological depth values along the divergent ray lines passing through the individual CT slices. Based on these RD values, asymmetrically shaped MLC apertures were defined every 9 mm of the phantom in superior-inferior direction. Individual MLC files were created with MATLAB™ and were imported into Eclipse™ treatment planning system for dose calculations. Lungs can be shielded to an optimum level by reducing the MLC aperture width over the lungs. The process was repeated with symmetrically shaped apertures. Results: Dose-volume histogram (DVH) analysis shows that the asymmetric MLC based technique provides better dose coverage to the body and optimum shielding of the lungs compared to symmetrically shaped beam apertures. Midline dose homogeneity is within ±3% with asymmetric MLC apertures whereas it remains within ±4.5% with symmetric ones (except head region where it drops down to −7%). The substantial over and under dosage of ±5% at tissue interfaces has been reduced to ±2% with asymmetric MLC technique. Lungs dose can be reduced to any desired limit. In this experiment lungs dose was reduced to 80% of the prescribed dose, as was desired. Conclusion: The novel asymmetric MLC based technique assures optimum shielding of OARs (e.g. lungs) and better 3-D dose homogeneity and body-dose coverage in comparison with the symmetric MLC aperture optimization. The authors acknowledge the financial and infrastructural support provided by Pakistan Institute of Engineering & Applied Sciences (PIEAS), Islamabad and Aga Khan University Hospital (AKUH), Karachi during the course of this research project. Authors have no conflict of interest with any national / international

  16. Impact of global transcriptional regulation by ArcA, ArcB, Cra, Crp, Cya, Fnr, and Mlc on glucose catabolism in Escherichia coli.

    Science.gov (United States)

    Perrenoud, Annik; Sauer, Uwe

    2005-05-01

    Even though transcriptional regulation plays a key role in establishing the metabolic network, the extent to which it actually controls the in vivo distribution of metabolic fluxes through different pathways is essentially unknown. Based on metabolism-wide quantification of intracellular fluxes, we systematically elucidated the relevance of global transcriptional regulation by ArcA, ArcB, Cra, Crp, Cya, Fnr, and Mlc for aerobic glucose catabolism in batch cultures of Escherichia coli. Knockouts of ArcB, Cra, Fnr, and Mlc were phenotypically silent, while deletion of the catabolite repression regulators Crp and Cya resulted in a pronounced slow-growth phenotype but had only a nonspecific effect on the actual flux distribution. Knockout of ArcA-dependent redox regulation, however, increased the aerobic tricarboxylic acid (TCA) cycle activity by over 60%. Like aerobic conditions, anaerobic derepression of TCA cycle enzymes in an ArcA mutant significantly increased the in vivo TCA flux when nitrate was present as an electron acceptor. The in vivo and in vitro data demonstrate that ArcA-dependent transcriptional regulation directly or indirectly controls TCA cycle flux in both aerobic and anaerobic glucose batch cultures of E. coli. This control goes well beyond the previously known ArcA-dependent regulation of the TCA cycle during microaerobiosis.

  17. Independent dose calculation of the Tps Iplan in radiotherapy conformed with MLC; Calculo independiente de dosis del TPS Iplan en radioterapia conformada con MLC

    Energy Technology Data Exchange (ETDEWEB)

    Adrada, A.; Tello, Z.; Medina, L.; Garrigo, E.; Venencia, D., E-mail: jorge.alberto.adrada@gmail.com [Instituto Privado de Radioterapia, Obispo Oro 423, X5000BFI Cordoba (Argentina)

    2014-08-15

    The systems utilization of independent dose calculation in three dimensional-Conformal Radiation Therapy (3D-Crt) treatments allows a direct verification of the treatments times. The utilization of these systems allows diminishing the probability of errors occurrence generated by the treatment planning system (Tps), allowing a detailed analysis of the dose to delivering and review of the normalization point (Np) or prescription. The independent dose calculation is realized across the knowledge of dosimetric parameters of the treatment machine and particular characteristics of every individual field. The aim of this work is develops a calculation system of punctual doses for isocentric fields conformed with multi-leaf collimation systems (MLC), where the dose calculation is in conformity with the suggested ones by ICRU Report No. 42, 1987. Calculation software was realized in C ++ under a free platform of programming (Code::Blocks). The system uses files in format Rtp, exported from the Tps to systems of record and verification (Lantis). This file contains detailed information of the dose, Um, position of the MLC sheets and collimators for every field of treatment. The size of equivalent field is obtained from the positions of every sheet; the effective depth of calculation can be introduced from the dosimetric report of the Tps or automatically from the DFS of the field. The 3D coordinates of the isocenter and the Np for the treatment plan must be introduced manually. From this information the system looks the dosimetric parameters and calculates the Um. The calculations were realized in two accelerators a NOVALIS Tx (Varian) with 120 sheets of high definition (hd-MLC) and a PRIMUS Optifocus (Siemens) with 82 sheets. 705 patients were analyzed for a total of 1082, in plans made for both equipment s, the average uncertainty with regard to the calculation of the Tps is-0.43% ± 2.42% in a range between [-7.90 %, 7.50 %]. The major uncertainty was in Np near of the

  18. Real-Time Dynamic MLC Tracking for Intensity Modulated Arc Therapy

    DEFF Research Database (Denmark)

    Falk, Marianne

    Motion management of intra-fraction tumour motion during radiotherapy treatment can be a challenging task in order to achieve tumour control as well as minimizing the dose to the surrounding healthy tissue. Real-time dynamic multileaf collimator (MLC) tracking is a novel method for intra-fraction...

  19. Measurement for the MLC leaf velocity profile by considering the leaf leakage using a radiographic film

    International Nuclear Information System (INIS)

    Chow, James C L; Grigorov, Grigor N

    2006-01-01

    A method to measure the velocity profile of a multi-leaf collimator (MLC) leaf along its travel range using a radiographic film is reported by considering the intra-leaf leakage. A specific dynamic MLC field with leaves travelling from the field edge to the isocentre line was designed. The field was used to expose a radiographic film, which was then scanned, and the dose profile along the horizontal leaf axis was measured. The velocity at a sampling point on the film can be calculated by considering the horizontal distance between the sampling point and the isocentre line, dose at the sampling point, dose rate of the linear accelerator, the total leaf travel time from the field edge to isocentre line and the pre-measured dose rate of leaf leakage. With the leaf velocities and velocity profiles for all MLC leaves measured routinely, a comprehensive and simple QA for the MLC can be set up to test the consistency of the leaf velocity performance which is essential to the IMRT delivery using a sliding window technique. (note)

  20. Leakage of the Siemens 160 MLC multileaf collimator on a dual energy linear accelerator

    International Nuclear Information System (INIS)

    Klueter, Sebastian; Sroka-Perez, Gabriele; Schubert, Kai; Debus, Juergen

    2011-01-01

    Multileaf collimators (MLCs) have been in clinical use for many years and meanwhile are commonly used to deliver intensity-modulated radiotherapy (IMRT) beams. For this purpose it is important to know their dosimetric properties precisely, one of them being inter- and intraleaf leakage. The Siemens 160 MLC features a single focus design with flat-sided and tilted leaves instead of tongue-and-groove. The leakage performance of the 160 MLC was investigated on a dual energy linear accelerator Siemens ARTISTE with 6 MV and 18 MV photon energies. While the intraleaf leakage amounted to nearly the same dose for 6 and for 18 MV, a much higher interleaf leakage for 6 MV was measured. It could be reduced by simply rotating the collimator, and also by changing the voltage applied to the beam steering coils. The leakage of the 160 MLC is shown to be sensitive to beam alignment. This is of special interest for dual energy accelerators, as the two focal spots of both energies, neither in position nor in shape, do not necessarily always coincide. As a consequence of that, a higher leakage can be expected for one out of two energies for the 160 MLC. (note)

  1. Metastasis of aggressive amoeboid sarcoma cells is dependent on Rho/ROCK/MLC signaling

    Czech Academy of Sciences Publication Activity Database

    Kosla, Jan; Paňková, D.; Plachý, Jiří; Tolde, O.; Bicanova, K.; Dvořák, Michal; Rosel, D.; Brabek, J.

    2013-01-01

    Roč. 11, č. 1 (2013), s. 51 ISSN 1478-811X R&D Projects: GA MŠk(CZ) LC06061 Institutional support: RVO:68378050 Keywords : metastasis * sarcoma * rhoA * ROCK * MLC * amoeboid invasiveness * 3D environment * chicken model Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.672, year: 2013

  2. Duffing–van der Pol oscillator type dynamics in Murali–Lakshmanan–Chua (MLC) circuit

    International Nuclear Information System (INIS)

    Srinivasan, K.; Chandrasekar, V.K.; Venkatesan, A.; Raja Mohamed, I.

    2016-01-01

    Highlights: • Proposed an electronic circuit with diode based nonlinear element equivalent to a well known Murali–Lakshmanan–Chua (MLC) circuit. • For chosen circuit parameters this circuit admits familiar MLC type attractor and also Duffing–van der Pol circuit type chaotic attractor. • The performance of the circuit is investigated by means of explicit laboratory experiments, numerical simulations and analytical studies. - Abstract: We have constructed a simple second-order dissipative nonautonomous circuit exhibiting ordered and chaotic behaviour. This circuit is the well known Murali–Lakshmanan–Chua(MLC) circuit but with diode based nonlinear element. For chosen circuit parameters this circuit admits familiar MLC type attractor and also Duffing–van der Pol circuit type chaotic attractors. It is interesting to note that depending upon the circuit parameters the circuit shows both period doubling route to chaos and quasiperiodic route to chaos. In our study we have constructed two-parameter bifurcation diagrams in the forcing amplitude–frequency plane, one parameter bifurcation diagrams, Lyapunov exponents, 0–1 test and phase portrait. The performance of the circuit is investigated by means of laboratory experiments, numerical integration of appropriate mathematical model and explicit analytic studies.

  3. SU-F-T-530: Characterization of a 60-Leaf Motorized MLC Designed for Cobalt-60 Units

    International Nuclear Information System (INIS)

    Xu, L; Smith, L; Ciresianu, A

    2016-01-01

    Purpose: In a continuing effort to improve conformal radiation therapy with Cobalt-60 units, a 60-leaf MLC was designed, manufactured, and released to market. This work describes the physics measurements taken to characterize the clinical performance of this MLC. Methods: A 60 leaf MLC was custom designed with tungsten leaves of 4.5 cm height, single focused, achieving field size of 30×30 cm^2 when mounted on a 100cm SAD Cobalt-60 unit. Leakage and output factor measurements were performed using a single ion chamber in a solid water phantom. Penumbra and surface dose were measured using scanning chambers and diodes in a water phantom. Radiation-light coincidence measurements were performed using radiographic films. Results: With MLC mounted, measured penumbras at all depths are smaller than with jaws only. Surface doses were not significantly affected by the presence of MLC, and remained below values recommended by regulatory bodies. Light-radiation coincidences were found to be better than 3 mm for all field sizes. Leakage through the MLC was found to be strongly dependent on field size, increasing from 1.0 % for a 10×10 cm field to 2.0% for a 30×30 cm field. Such results meet the requirements of IEC 60601-2-11. The MLC was found to have significant influence on the output factor, when field size defined by MLC is significantly smaller than field size defined by jaws. Such effect is also observed on linear accelerators, but it is more pronounced on Cobalt-60 units. A 10×10 “diamond” MLC shape inside a 14×14 cm jaw showed output factor that is 5.7% higher than 10×10 cm field defined by matching MLC and jaws. Conclusion: The MLC offers clinically acceptable performance in penumbra, surface dose, and light-radiation coincidence. Several units of this MLC have recently been installed and used clinically. Validation of Cobalt-60 based IMRT with this MLC is ongoing. The authors are employees of Best Theratrnics Ltd.

  4. SU-F-T-530: Characterization of a 60-Leaf Motorized MLC Designed for Cobalt-60 Units

    Energy Technology Data Exchange (ETDEWEB)

    Xu, L; Smith, L; Ciresianu, A [Best Theratronics, Ottawa, ON (Canada)

    2016-06-15

    Purpose: In a continuing effort to improve conformal radiation therapy with Cobalt-60 units, a 60-leaf MLC was designed, manufactured, and released to market. This work describes the physics measurements taken to characterize the clinical performance of this MLC. Methods: A 60 leaf MLC was custom designed with tungsten leaves of 4.5 cm height, single focused, achieving field size of 30×30 cm^2 when mounted on a 100cm SAD Cobalt-60 unit. Leakage and output factor measurements were performed using a single ion chamber in a solid water phantom. Penumbra and surface dose were measured using scanning chambers and diodes in a water phantom. Radiation-light coincidence measurements were performed using radiographic films. Results: With MLC mounted, measured penumbras at all depths are smaller than with jaws only. Surface doses were not significantly affected by the presence of MLC, and remained below values recommended by regulatory bodies. Light-radiation coincidences were found to be better than 3 mm for all field sizes. Leakage through the MLC was found to be strongly dependent on field size, increasing from 1.0 % for a 10×10 cm field to 2.0% for a 30×30 cm field. Such results meet the requirements of IEC 60601-2-11. The MLC was found to have significant influence on the output factor, when field size defined by MLC is significantly smaller than field size defined by jaws. Such effect is also observed on linear accelerators, but it is more pronounced on Cobalt-60 units. A 10×10 “diamond” MLC shape inside a 14×14 cm jaw showed output factor that is 5.7% higher than 10×10 cm field defined by matching MLC and jaws. Conclusion: The MLC offers clinically acceptable performance in penumbra, surface dose, and light-radiation coincidence. Several units of this MLC have recently been installed and used clinically. Validation of Cobalt-60 based IMRT with this MLC is ongoing. The authors are employees of Best Theratrnics Ltd.

  5. The emergence of non-cytolytic NK1.1+ T cells in the long-term culture of murine tumour-infiltrating lymphocytes: a possible role of transforming growth factor-beta.

    Science.gov (United States)

    Tamada, K; Harada, M; Ito, O; Takenoyama, M; Mori, T; Matsuzaki, G; Nomoto, K

    1996-12-01

    The mechanism by which murine tumour-infiltrating lymphocytes (TIL) decreased their anti-tumour activity during an in vitro culture with interleukin-2 (IL-2) was investigated. A phenotype analysis revealed that the TIL cultured for 7 days (TIL-d7) were exclusively NKI.1- CD4- CD8+ CD3+ cells and that this population was replaced by natural killer (NK)1.1+ CD4- CD8 CD3+ cells by day 27 (TIL-d27) during the culture of TIL. The TIL-d7 cells showed a cytolytic activity against B16 melanoma, whereas the TIL-d27 cells had lost this activity, suggesting that the decrease in the anti tumour effect of TIL during the culture with IL-2 was due to their populational change. Analysis on the characteristics of the TIL-d27 cells revealed that they expressed skewed T-cell receptor (TCR) V beta 5 and increased mRNA expression of V alpha 14. In addition, they expressed transforming growth factor beta (TGF-beta) mRNA. Interestingly, TGF-beta augmented the proliferation of TIL-d27 cells under the presence of IL-2, but suppressed that of TIL-d7 cells. Moreover, the proliferation of TIL-d27 cells was suppressed by anti-TGF-beta monoclonal antibody. Collectively, these results suggest that, in contrast to its suppressive effect on anti-tumour effector T cells. TGF-beta could be an autocrine growth factor for NKL1.1+ T cells and thereby induce non-cytolytic NK1.1+ T cells in the long-term culture of TIL.

  6. Dosimetry of a prototype retractable eMLC for fixed-beam electron therapy

    International Nuclear Information System (INIS)

    Hogstrom, Kenneth R.; Boyd, Robert A.; Antolak, John A.; Svatos, Michelle M.; Faddegon, Bruce A.; Rosenman, Julian G.

    2004-01-01

    An electron multileaf collimator (eMLC) has been designed that is unique in that it retracts to 37 cm from the isocenter [63-cm source-to-collimator distance (SCD)] and can be deployed to distances of 20 and 10 cm from the isocenter (80 and 90 cm SCD, respectively). It is expected to be capable of arc therapy at 63 cm SCD; isocentric, fixed-beam therapy at 80 cm SCD; and source-to-surface distance (SSD), fixed-beam therapy at 90 cm SCD. In all positions, its leaves could be used for unmodulated or intensity-modulated therapy. Our goal in the present work is to describe the general characteristics of the eMLC and to demonstrate that its leakage characteristics and dosimetry are adequate for SSD, fixed-beam therapy as an alternative to Cerrobend cutouts with applicators once the prototype's leaves are motorized. Our eMLC data showed interleaf electron leakage at 15 MeV to be less than 0.1% based on a 0.0025 cm manufacturing tolerance, and lateral electron leakage at 5 and 15 MeV to be less than 2%. X-ray leakage through the leaves was 1.6% at 15 MeV. Our data showed that beam penumbra was independent of direction and leaf position. The dosimetric properties of square fields formed by the eMLC were very consistent with those formed by Cerrobend inserts in the 20x20 cm 2 applicator. Output factors exhibited similar field-size dependence. Airgap factors exhibited almost identical field-size dependence at two SSDs (105 and 110 cm), consistent with the common assumption that airgap factors are applicator independent. Percent depth-dose curves were similar, but showed variations up to 3% in the buildup region. The pencil-beam algorithm (PBA) fit measured data from the eMLC and applicator-cutout systems equally well, and the resulting two-dimensional (2-D) dose distributions, as predicted by the PBA, agreed well at common airgap distance. Simulating patient setups for breast and head and neck treatments showed that almost all fields could be treated using similar SSDs as

  7. 6 MV dosimetric characterization of the 160 MLC, the new Siemens multileaf collimator

    International Nuclear Information System (INIS)

    Tacke, Martin B.; Nill, Simeon; Haering, Peter; Oelfke, Uwe

    2008-01-01

    New technical developments constantly aim at improving the outcome of radiation therapy. With the use of a computer-controlled multileaf collimator (MLC), the quality of the treatment and the efficiency in patient throughput is significantly increased. New MLC designs aim to further enhance the advantages. In this article, we present the first detailed experimental investigation of the new 160 MLC TM , Siemens Medical Solutions. The assessment included the experimental investigation of typical MLC characteristics such as leakage, tongue-and-groove effect, penumbra, leaf speed, and leaf positioning accuracy with a 6 MV treatment beam. The leakage is remarkably low with an average of 0.37% due to a new design principle of slightly tilted leaves instead of the common tongue-and-groove design. But due to the tilt, the triangular tongue-and-groove effect occurs. Its magnitude of approximately 19% is similar to the dose defect measured for MLCs with the common tongue-and-groove design. The average longitudinal penumbra measured at depth d max =15 mm with standard 100x100 mm 2 fields is 4.1±0.5 mm for the central range and increases to 4.9±1.3 mm for the entire field range of 400x400 mm 2 . The increase is partly due to the single-focusing design and the large distance between the MLC and the isocenter enabling a large patient clearance. Regarding the leaf speed, different velocity tests were performed. The positions of the moving leaves were continuously recorded with the kilovoltage-imaging panel. The maximum leaf velocities measured were 42.9±0.6 mm/s. In addition, several typical intensity-modulated radiation therapy treatments were performed and the delivery times compared to the Siemens OPTIFOCUS MLC. An average decrease of 11% in delivery time was observed. The experimental results presented in this article indicate that the dosimetric characteristics of the 160 MLC are capable of improving the quality of dose delivery with respect to precision and dose

  8. Electron beam collimation with a photon MLC for standard electron treatments

    Science.gov (United States)

    Mueller, S.; Fix, M. K.; Henzen, D.; Frei, D.; Frauchiger, D.; Loessl, K.; Stampanoni, M. F. M.; Manser, P.

    2018-01-01

    Standard electron treatments are currently still performed using standard or molded patient-specific cut-outs placed in the electron applicator. Replacing cut-outs and electron applicators with a photon multileaf collimator (pMLC) for electron beam collimation would make standard electron treatments more efficient and would facilitate advanced treatment techniques like modulated electron radiotherapy (MERT) and mixed beam radiotherapy (MBRT). In this work, a multiple source Monte Carlo beam model for pMLC shaped electron beams commissioned at a source-to-surface distance (SSD) of 70 cm is extended for SSDs of up to 100 cm and validated for several Varian treatment units with field sizes typically used for standard electron treatments. Measurements and dose calculations agree generally within 3% of the maximal dose or 2 mm distance to agreement. To evaluate the dosimetric consequences of using pMLC collimated electron beams for standard electron treatments, pMLC-based and cut-out-based treatment plans are created for a left and a right breast boost, a sternum, a testis and a parotid gland case. The treatment plans consist of a single electron field, either alone (1E) or in combination with two 3D conformal tangential photon fields (1E2X). For each case, a pMLC plan with similar treatment plan quality in terms of dose homogeneity to the target and absolute mean dose values to the organs at risk (OARs) compared to a cut-out plan is found. The absolute mean dose to an OAR is slightly increased for pMLC-based compared to cut-out-based 1E plans if the OAR is located laterally close to the target with respect to beam direction, or if a 6 MeV electron beam is used at an extended SSD. In conclusion, treatment plans using cut-out collimation can be replaced by plans of similar treatment plan quality using pMLC collimation with accurately calculated dose distributions.

  9. A multi-institution evaluation of MLC log files and performance in IMRT delivery

    International Nuclear Information System (INIS)

    Kerns, James R; Childress, Nathan; Kry, Stephen F

    2014-01-01

    The multileaf collimator (MLC) is a critical component to accurate intensity-modulated radiotherapy (IMRT) delivery. This study examined MLC positional accuracy via MLC logs from Varian machines from six institutions and three delivery techniques to evaluate typical positional accuracy and treatment and mechanical parameters that affect accuracy. Typical accuracy achieved was compared against TG-142 recommendations for MLC performance; more appropriate recommendations are suggested. Over 85,000 Varian MLC treatment logs were collected from six institutions and analyzed with FractionCHECK. Data were binned according to institution and treatment type to determine overall root mean square (RMS) and 95 th percentile error values, and then to look for correlations between those errors and with mechanical and treatment parameters including mean and maximum leaf speed, gantry angle, beam-on time, mean leaf error, and number of segments. Results of treatment logs found that leaf RMS error and 95 th percentile leaf error were consistent between institutions, but varied by treatment type. The step and shoot technique had very small errors: the mean RMS leaf error was 0.008 mm. For dynamic treatments the mean RMS leaf error was 0.32 mm, while volumetric-modulated arc treatment (VMAT) showed an RMS leaf error of 0.46 mm. Most MLC leaf errors were found to be well below TG-142 recommended tolerances. For the dynamic and VMAT techniques, the mean and maximum leaf speeds were significantly linked to the leaf RMS error. Additionally, for dynamic delivery, the mean leaf error was correlated with RMS error, whereas for VMAT the average gantry speed was correlated. For all treatments, the RMS error and the 95 th percentile leaf error were correlated. Restricting the maximum leaf speed can help improve MLC performance for dynamic and VMAT deliveries. Furthermore, the tolerances of leaf RMS and error counts for all treatment types should be tightened from the TG-142 values to make them

  10. Impact of the MLC on the MRI field distortion of a prototype MRI-linac

    International Nuclear Information System (INIS)

    Kolling, Stefan; Keall, Paul; Oborn, Brad

    2013-01-01

    Purpose: To cope with intrafraction tumor motion, integrated MRI-linac systems for real-time image guidance are currently under development. The multileaf collimator (MLC) is a key component in every state-of-the-art radiotherapy treatment system, allowing for accurate field shaping and tumor tracking. This work quantifies the magnetic impact of a widely used MLC on the MRI field homogeneity for such a modality.Methods: The finite element method was employed to model a MRI-linac assembly comprised of a 1.0 T split-bore MRI magnet and the key ferromagnetic components of a Varian Millennium 120 MLC, namely, the leaves and motors. Full 3D magnetic field maps of the system were generated. From these field maps, the peak-to-peak distortion within the MRI imaging volume was evaluated over a 30 cm diameter sphere volume (DSV) around the isocenter and compared to a maximum preshim inhomogeneity of 300 μT. Five parametric studies were performed: (1) The source-to-isocenter distance (SID) was varied from 100 to 200 cm, to span the range of a compact system to that with lower magnetic coupling. (2) The MLC model was changed from leaves only to leaves with motors, to determine the contribution to the total distortion caused by MLC leaves and motors separately. (3) The system was configured in the inline or perpendicular orientation, i.e., the linac treatment beam was oriented parallel or perpendicular to the magnetic field direction. (4) The treatment field size was varied from 0 × 0 to 20×20 cm 2 , to span the range of clinical treatment fields. (5) The coil currents were scaled linearly to produce magnetic field strengths B 0 of 0.5, 1.0, and 1.5 T, to estimate how the MLC impact changes with B 0 .Results: (1) The MLC-induced MRI field distortion fell continuously with increasing SID. (2) MLC leaves and motors were found to contribute to the distortion in approximately equal measure. (3) Due to faster falloff of the fringe field, the field distortion was

  11. Quantifying the gantry sag on linear accelerators and introducing an MLC-based compensation strategy

    Energy Technology Data Exchange (ETDEWEB)

    Du Weiliang; Gao Song; Wang Xiaochun; Kudchadker, Rajat J. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2012-04-15

    Purpose: Gantry sag is one of the well-known sources of mechanical imperfections that compromise the spatial accuracy of radiation dose delivery. The objectives of this study were to quantify the gantry sag on multiple linear accelerators (linacs), to investigate a multileaf collimator (MLC)-based strategy to compensate for gantry sag, and to verify the gantry sag and its compensation with film measurements. Methods: The authors used the Winston-Lutz method to measure gantry sag on three Varian linacs. A ball bearing phantom was imaged with megavolt radiation fields at 10 deg. gantry angle intervals. The images recorded with an electronic portal imaging device were analyzed to derive the radiation isocenter and the gantry sag, that is, the superior-inferior wobble of the radiation field center, as a function of the gantry angle. The authors then attempted to compensate for the gantry sag by applying a gantry angle-specific correction to the MLC leaf positions. The gantry sag and its compensation were independently verified using film measurements. Results: Gantry sag was reproducible over a six-month measurement period. The maximum gantry sag was found to vary from 0.7 to 1.0 mm, depending on the linac and the collimator angle. The radiation field center moved inferiorly (i.e., away from the gantry) when the gantry was rotated from 0 deg. to 180 deg. After the MLC leaf position compensation was applied at 90 deg. collimator angle, the maximum gantry sag was reduced to <0.2 mm. The film measurements at gantry angles of 0 deg. and 180 deg. verified the inferior shift of the radiation fields and the effectiveness of MLC compensation. Conclusions: The results indicate that gantry sag on a linac can be quantitatively measured using a simple phantom and an electronic portal imaging device. Reduction of gantry sag is feasible by applying a gantry angle-specific correction to MLC leaf positions at 90 deg. collimator angle.

  12. Genetic polymorphisms in 19q13.3 genes associated with alteration of repair capacity to BPDE-DNA adducts in primary cultured lymphocytes.

    Science.gov (United States)

    Xiao, Mingyang; Xiao, Sha; Straaten, Tahar van der; Xue, Ping; Zhang, Guopei; Zheng, Xiao; Zhang, Qianye; Cai, Yuan; Jin, Cuihong; Yang, Jinghua; Wu, Shengwen; Zhu, Guolian; Lu, Xiaobo

    2016-12-01

    Benzo[a]pyrene(B[a]P), and its ultimate metabolite Benzo[a]pyrene 7,8-diol 9,10-epoxide (BPDE), are classic DNA damaging carcinogens. DNA damage in cells caused by BPDE is normally repaired by Nucleotide Excision Repair (NER) and Base Excision Repair (BER). Genetic variations in NER and BER can change individual DNA repair capacity to DNA damage induced by BPDE. In the present study we determined the number of in vitro induced BPDE-DNA adducts in lymphocytes, to reflect individual susceptibility to Polycyclic aromatic hydrocarbons (PAHs)-induced carcinogenesis. The BPDE-DNA adduct level in lymphocytes were assessed by high performance liquid chromatography (HPLC) in 281 randomly selected participants. We genotyped for 9 single nucleotide polymorphisms (SNPs) in genes involved in NER (XPB rs4150441, XPC rs2228001, rs2279017 and XPF rs4781560), BER (XRCC1 rs25487, rs25489 and rs1799782) and genes located on chromosome 19q13.2-3 (PPP1R13L rs1005165 and CAST rs967591). We found that 3 polymorphisms in chromosome 19q13.2-3 were associated with lower levels of BPDE-DNA adducts (MinorT allele in XRCC1 rs1799782, minor T allele in PPP1R13L rs1005165 and minor A allele in CAST rs967571). In addition, a modified comet assay was performed to further confirm the above conclusions. We found both minor T allele in PPP1R13L rs1005165 and minor A allele in CAST rs967571 were associated with the lower levels of BPDE-adducts. Our data suggested that the variant genotypes of genes in chromosome 19q13.2-3 are associated with the alteration of repair efficiency to DNA damage caused by Benzo[a]pyrene, and may contribute to enhance predictive value for individual's DNA repair capacity in response to environmental carcinogens. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Comparison of two methods for quantifying the accuracy of the positioning of the blades of the MLC

    International Nuclear Information System (INIS)

    Garcia Yip, Fernando; Silvestre Patallo, Ileana; Diaz Moreno, Rogelio

    2009-01-01

    Conformal radiotherapy treatment (3DCRT) and intensity modulated (IMRT) require more accurate positioning of the blades collimator. The procedure Stanford Quality Control (QC) is based MLC determine the possibility of small errors in positioning (<1mm) to from the variation that occurs in the relative response of a small detector depending on the irradiated fraction of its volume. The aim of this work was to establish a methodology to characterize quantitatively individual displacements of each layer, taking into account the tolerances established for 3DCRT and IMRT are ± 1mm. We determined the accuracy of the positioning of the throttle blades MLC Elekta Precise linear (S/N1220) of INOR. The MLC has 40 pairs of sheets tungsten 1 cm wide at the isocenter. The lower jaws of the collimator side is backed by the MLC. We compare two variants Stanford technique, one, using as detector portal imaging system Electronics (EPID) and the other using the two-dimensional camera system ionization 2D array (PTW 729). We used analysis tools programmed in MatLab image and application to MLC Checker processing the signals of the 2D array. We established the reference values of the relative response of detectors employees (EPID and 2D array) for the 40 pairs of blades to MLC and positions of both banks from 13cm-13cm and up to 1cm intervals. It implemented a procedure for the routine application of this test in MLC monthly checks. Procedure was applied as part of systematic quality control of MLC and found the mean error of positioning of each blade from the implementation of the QC procedure and to carry out this work. It was verified that the linac MLC 1220 of INOR meets tolerances established for the delivery of advanced treatment techniques 3D conformal radiotherapy and IMRT. (author)

  14. Role of oxidative stress and intracellular calcium in nickel carbonate hydroxide-induced sister-chromatid exchange, and alterations in replication index and mitotic index in cultured human peripheral blood lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    M' Bemba-Meka, Prosper [Universite de Montreal, Human Toxicology Research Group (TOXHUM), Department of Environmental and Occupational Health, Main Station, P.O. Box 6128, Montreal, QC (Canada); University of Louisville, Department of Pharmacology and Toxicology, Center for Genetics and Molecular Medicine, Louisville, KY (United States); Lemieux, Nicole [Universite de Montreal, Department of Pathology and Cellular Biology, Faculty of Medicine, Main Station, P.O. Box 6128, Montreal, QC (Canada); Chakrabarti, Saroj K. [Universite de Montreal, Human Toxicology Research Group (TOXHUM), Department of Environmental and Occupational Health, Main Station, P.O. Box 6128, Montreal, QC (Canada)

    2007-02-15

    Human peripheral lymphocytes from whole blood cultures were exposed to either soluble form of nickel carbonate hydroxide (NiCH) (0-60 {mu}M), or of nickel subsulfide (Ni{sub 3}S{sub 2}) (0-120 {mu}M), or of nickel oxide (NiO) (0-120 {mu}M), or nickel sulfate (NiSO{sub 4}) (0-120 {mu}M) for a short duration of 2 h. The treatments occurred 46 h after the beginning of the cultures. The cultures were harvested after a total incubation of 72 h, and sister-chromatid exchange (SCE), replication index (RI), and mitotic index (MI) were measured for each nickel compound. The soluble form of NiCH at 30 {mu}M but those of Ni{sub 3}S{sub 2} and NiO at 120 {mu}M produced significant increase in the SCE per cell compared to the control value, whereas NiSO{sub 4} failed to produce any such significant increase. Except NiSO{sub 4}, the soluble forms of NiCH, Ni{sub 3}S{sub 2}, and NiO produced significant cell-cycle delay (as measured by the inhibition of RI) as well as significant inhibition of the MI at respective similar concentrations as mentioned above. Pretreatment of human blood lymphocytes with catalase (H{sub 2}O{sub 2} scavenger), or superoxide dismutase (superoxide anion scavenger), or dimethylthiourea (hydroxyl radical scavenger), or deferoxamine (iron chelator), or N-acetylcysteine (general antioxidant) inhibited NiCH-induced SCE, and changes in RI and MI. This suggests the participation of oxidative stress involving H{sub 2}O{sub 2}, the superoxide anion radical, the hydroxyl radical, and iron in the NiCH-induced genotoxic responses. Cotreatment of NiCH with either verapamil (inhibitor of intracellular calcium ion ([Ca{sup 2+}]{sub i}) movement through plasma membranes), or dantrolene (inhibitor of [Ca{sup 2+}]{sub i} release from sarcoplasmic reticulum), or BAPTA (Ca{sup 2+} chelator) also inhibited the NiCH-induced responses. These results suggest that [Ca{sup 2+}]{sub i} is also implicated in the genotoxicity of NiCH. Overall these data indicate that various types

  15. Allograft immunity in vitro. I. Cultivation conditions and mixed lymphocyte interaction of mouse peripheral lymphocytes

    Science.gov (United States)

    Häyry, P.; Defendi, V.

    1970-01-01

    We have adapted mouse peripheral lymphocytes to culture as a preliminary step in designing a model for the study of allograft immunity in vitro. The isolation of peripheral leucocytes is facilitated by using Plasmagel® as an erythrocyte-agglutinating agent. The yield of leucocytes can be considerably increased by intravenous injection of the donor animals with supernatant fluid from Bordetella pertussis cultures and the lymphocytes thus mobilized react both to phytohaemagglutinin (PHA) and allogeneic stimulus, as do lymphocytes from untreated animals. Preparations which contain more than 25–50 RBC/WBC are refractory in the mixed lymphocyte interaction (MLI). The optimum cell density for the proliferative response is approximately 1–3 × 106 lymphocytes/ml. Various nutritive milieu were tested and found to have little influence on the MLI; both normal and suspension media behaved in a similar manner. PHA causes a vigorous proliferative response in mouse peripheral lymphocytes, the 3H–TdR incorporation values in PHA-containing cultures at peak point of stimulation (3rd day) being up to 1000 times those observed for control cultures. The allogeneic response in the MLI takes place later (6th to 7th day) and is weaker, about one-tenth the PHA response, when strains differing at the H-2 locus are used as cell donors. Because the specific proliferative response to allogeneic stimulus in mixed culture, regardless of the way it is measured, is indistinguishable from the response produced by other non-specific factors, these other factors must be critically excluded. It appears that supplementing the culture medium with low concentrations of certain lots of foetal calf or agamma-newborn-calf serum permits the study of the specific response at an optimum sensitivity. PMID:4315207

  16. Online 4D ultrasound guidance for real-time motion compensation by MLC tracking.

    Science.gov (United States)

    Ipsen, Svenja; Bruder, Ralf; O'Brien, Rick; Keall, Paul J; Schweikard, Achim; Poulsen, Per R

    2016-10-01

    With the trend in radiotherapy moving toward dose escalation and hypofractionation, the need for highly accurate targeting increases. While MLC tracking is already being successfully used for motion compensation of moving targets in the prostate, current real-time target localization methods rely on repeated x-ray imaging and implanted fiducial markers or electromagnetic transponders rather than direct target visualization. In contrast, ultrasound imaging can yield volumetric data in real-time (3D + time = 4D) without ionizing radiation. The authors report the first results of combining these promising techniques-online 4D ultrasound guidance and MLC tracking-in a phantom. A software framework for real-time target localization was installed directly on a 4D ultrasound station and used to detect a 2 mm spherical lead marker inside a water tank. The lead marker was rigidly attached to a motion stage programmed to reproduce nine characteristic tumor trajectories chosen from large databases (five prostate, four lung). The 3D marker position detected by ultrasound was transferred to a computer program for MLC tracking at a rate of 21.3 Hz and used for real-time MLC aperture adaption on a conventional linear accelerator. The tracking system latency was measured using sinusoidal trajectories and compensated for by applying a kernel density prediction algorithm for the lung traces. To measure geometric accuracy, static anterior and lateral conformal fields as well as a 358° arc with a 10 cm circular aperture were delivered for each trajectory. The two-dimensional (2D) geometric tracking error was measured as the difference between marker position and MLC aperture center in continuously acquired portal images. For dosimetric evaluation, VMAT treatment plans with high and low modulation were delivered to a biplanar diode array dosimeter using the same trajectories. Dose measurements with and without MLC tracking were compared to a static reference dose using 3%/3 mm and 2

  17. Quality assurance of MLC leaf position accuracy and relative dose effect at the MLC abutment region using an electronic portal imaging device

    International Nuclear Information System (INIS)

    Sumida, Iori; Yamaguchi, Hajime; Kizaki, Hisao; Koizumi, Masahiko; Ogata, Toshiyuki; Takahashi, Yutaka; Yoshioka, Yasuo

    2012-01-01

    We investigated an electronic portal image device (EPID)-based method to see whether it provides effective and accurate relative dose measurement at abutment leaves in terms of positional errors of the multi-leaf collimator (MLC) leaf position. A Siemens ONCOR machine was used. For the garden fence test, a rectangular field (0.2x20 cm) was sequentially irradiated 11 times at 2-cm intervals. Deviations from planned leaf positions were calculated. For the nongap test, relative doses at the MLC abutment region were evaluated by sequential irradiation of a rectangular field (2x20 cm) 10 times with a MLC separation of 2 cm without a leaf gap. The integral signal in a region of interest was set to position A (between leaves) and B (neighbor of A). A pixel value at position B was used as background and the pixel ratio (A/Bx100) was calculated. Both tests were performed at four gantry angles (0, 90, 180 and 270deg) four times over 1 month. For the nongap test the difference in pixel ratio between the first and last period was calculated. Regarding results, average deviations from planned positions with the garden fence test were within 0.5 mm at all gantry angles, and at gantry angles of 90 and 270deg tended to decrease gradually over the month. For the nongap test, pixel ratio tended to increase gradually in all leaves, leading to a decrease in relative doses at abutment regions. This phenomenon was affected by both gravity arising from the gantry angle, and the hardware-associated contraction of field size with this type of machine. (author)

  18. Brushed permanent magnet DC MLC motor operation in an external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Yun, J.; St Aubin, J.; Rathee, S.; Fallone, B. G. [Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada); Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada); Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada) and Department of Oncology, Medical Physics Division, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2010-05-15

    Purpose: Linac-MR systems for real-time image-guided radiotherapy will utilize the multileaf collimators (MLCs) to perform conformal radiotherapy and tumor tracking. The MLCs would be exposed to the external fringe magnetic fields of the linac-MR hybrid systems. Therefore, an experimental investigation of the effect of an external magnetic field on the brushed permanent magnet DC motors used in some MLC systems was performed. Methods: The changes in motor speed and current were measured for varying external magnetic field strengths up to 2000 G generated by an EEV electromagnet. These changes in motor characteristics were measured for three orientations of the motor in the external magnetic field, mimicking changes in motor orientations due to installation and/or collimator rotations. In addition, the functionality of the associated magnetic motor encoder was tested. The tested motors are used with the Varian 120 leaf Millennium MLC (Maxon Motor half leaf and full leaf motors) and the Varian 52 leaf MKII MLC (MicroMo Electronics leaf motor) including a carriage motor (MicroMo Electronics). Results: In most cases, the magnetic encoder of the motors failed prior to any damage to the gearbox or the permanent magnet motor itself. This sets an upper limit of the external magnetic field strength on the motor function. The measured limits of the external magnetic fields were found to vary by the motor type. The leaf motor used with a Varian 52 leaf MKII MLC system tolerated up to 450{+-}10 G. The carriage motor tolerated up to 2000{+-}10 G field. The motors used with the Varian 120 leaf Millennium MLC system were found to tolerate a maximum of 600{+-}10 G. Conclusions: The current Varian MLC system motors can be used for real-time image-guided radiotherapy coupled to a linac-MR system, provided the fringe magnetic fields at their locations are below the determined tolerance levels. With the fringe magnetic fields of linac-MR systems expected to be larger than the

  19. Brushed permanent magnet DC MLC motor operation in an external magnetic field.

    Science.gov (United States)

    Yun, J; St Aubin, J; Rathee, S; Fallone, B G

    2010-05-01

    Linac-MR systems for real-time image-guided radiotherapy will utilize the multileaf collimators (MLCs) to perform conformal radiotherapy and tumor tracking. The MLCs would be exposed to the external fringe magnetic fields of the linac-MR hybrid systems. Therefore, an experimental investigation of the effect of an external magnetic field on the brushed permanent magnet DC motors used in some MLC systems was performed. The changes in motor speed and current were measured for varying external magnetic field strengths up to 2000 G generated by an EEV electromagnet. These changes in motor characteristics were measured for three orientations of the motor in the external magnetic field, mimicking changes in motor orientations due to installation and/or collimator rotations. In addition, the functionality of the associated magnetic motor encoder was tested. The tested motors are used with the Varian 120 leaf Millennium MLC (Maxon Motor half leaf and full leaf motors) and the Varian 52 leaf MKII MLC (MicroMo Electronics leaf motor) including a carriage motor (MicroMo Electronics). In most cases, the magnetic encoder of the motors failed prior to any damage to the gearbox or the permanent magnet motor itself. This sets an upper limit of the external magnetic field strength on the motor function. The measured limits of the external magnetic fields were found to vary by the motor type. The leaf motor used with a Varian 52 leaf MKII MLC system tolerated up to 450 +/- 10 G. The carriage motor tolerated up to 2000 +/- 10 G field. The motors used with the Varian 120 leaf Millennium MLC system were found to tolerate a maximum of 600 +/- 10 G. The current Varian MLC system motors can be used for real-time image-guided radiotherapy coupled to a linac-MR system, provided the fringe magnetic fields at their locations are below the determined tolerance levels. With the fringe magnetic fields of linac-MR systems expected to be larger than the tolerance levels determined, some form of

  20. MLC quality assurance using EPID: A fitting technique with subpixel precision

    International Nuclear Information System (INIS)

    Mamalui-Hunter, Maria; Li, Harold; Low, Daniel A.

    2008-01-01

    Amorphous silicon based electronic portal imaging devices (EPIDs) have been shown to be a good alternative to radiographic film for routine quality assurance (QA) of multileaf collimator (MLC) positioning accuracy. In this work, we present a method of acquiring an EPID image of a traditional strip-test image using analytical fits of the interleaf and leaf abutment image signatures. After exposure, the EPID image pixel values are divided by an open field image to remove EPID response and radiation field variations. Profiles acquired in the direction orthogonal to the leaf motion exhibit small peaks caused by interleaf leakage. Gaussian profiles are fitted to the interleaf leakage peaks, the results of which are, using multiobjective optimization, used to calculate the image rotational angle with respect to the collimator axis of rotation. The relative angle is used to rotate the image to align the MLC leaf travel to the image pixel axes. The leaf abutments also present peaks that are fitted by heuristic functions, in this case modified Lorentzian functions. The parameters of the Lorentzian functions are used to parameterize the leaf gap width and positions. By imaging a set of MLC fields with varying gaps forming symmetric and asymmetric abutments, calibration curves with regard to relative peak height (RPH) versus nominal gap width are obtained. Based on this calibration data, the individual leaf positions are calculated to compare with the nominal programmed positions. The results demonstrate that the collimator rotation angle can be determined as accurate as 0.01 deg. . A change in MLC gap width of 0.2 mm leads to a change in RPH of about 10%. For asymmetrically produced gaps, a 0.2 mm MLC leaf gap width change causes 0.2 pixel peak position change. Subpixel resolution is obtained by using a parameterized fit of the relatively large abutment peaks. By contrast, for symmetrical gap changes, the peak position remains unchanged with a standard deviation of 0

  1. EPID-based verification of the MLC performance for dynamic IMRT and VMAT

    International Nuclear Information System (INIS)

    Rowshanfarzad, Pejman; Sabet, Mahsheed; Barnes, Michael P.; O’Connor, Daryl J.; Greer, Peter B.

    2012-01-01

    Purpose: In advanced radiotherapy treatments such as intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT), verification of the performance of the multileaf collimator (MLC) is an essential part of the linac QA program. The purpose of this study is to use the existing measurement methods for geometric QA of the MLCs and extend them to more comprehensive evaluation techniques, and to develop dedicated robust algorithms to quantitatively investigate the MLC performance in a fast, accurate, and efficient manner. Methods: The behavior of leaves was investigated in the step-and-shoot mode by the analysis of integrated electronic portal imaging device (EPID) images acquired during picket fence tests at fixed gantry angles and arc delivery. The MLC was also studied in dynamic mode by the analysis of cine EPID images of a sliding gap pattern delivered in a variety of conditions including different leaf speeds, deliveries at fixed gantry angles or in arc mode, and changing the direction of leaf motion. The accuracy of the method was tested by detection of the intentionally inserted errors in the delivery patterns. Results: The algorithm developed for the picket fence analysis was able to find each individual leaf position, gap width, and leaf bank skewness in addition to the deviations from expected leaf positions with respect to the beam central axis with sub-pixel accuracy. For the three tested linacs over a period of 5 months, the maximum change in the gap width was 0.5 mm, the maximum deviation from the expected leaf positions was 0.1 mm and the MLC skewness was up to 0.2°. The algorithm developed for the sliding gap analysis could determine the velocity and acceleration/deceleration of each individual leaf as well as the gap width. There was a slight decrease in the accuracy of leaf performance with increasing leaf speeds. The analysis results were presented through several graphs. The accuracy of the method was assessed as 0.01 mm

  2. Brushed permanent magnet DC MLC motor operation in an external magnetic field

    International Nuclear Information System (INIS)

    Yun, J.; St Aubin, J.; Rathee, S.; Fallone, B. G.

    2010-01-01

    Purpose: Linac-MR systems for real-time image-guided radiotherapy will utilize the multileaf collimators (MLCs) to perform conformal radiotherapy and tumor tracking. The MLCs would be exposed to the external fringe magnetic fields of the linac-MR hybrid systems. Therefore, an experimental investigation of the effect of an external magnetic field on the brushed permanent magnet DC motors used in some MLC systems was performed. Methods: The changes in motor speed and current were measured for varying external magnetic field strengths up to 2000 G generated by an EEV electromagnet. These changes in motor characteristics were measured for three orientations of the motor in the external magnetic field, mimicking changes in motor orientations due to installation and/or collimator rotations. In addition, the functionality of the associated magnetic motor encoder was tested. The tested motors are used with the Varian 120 leaf Millennium MLC (Maxon Motor half leaf and full leaf motors) and the Varian 52 leaf MKII MLC (MicroMo Electronics leaf motor) including a carriage motor (MicroMo Electronics). Results: In most cases, the magnetic encoder of the motors failed prior to any damage to the gearbox or the permanent magnet motor itself. This sets an upper limit of the external magnetic field strength on the motor function. The measured limits of the external magnetic fields were found to vary by the motor type. The leaf motor used with a Varian 52 leaf MKII MLC system tolerated up to 450±10 G. The carriage motor tolerated up to 2000±10 G field. The motors used with the Varian 120 leaf Millennium MLC system were found to tolerate a maximum of 600±10 G. Conclusions: The current Varian MLC system motors can be used for real-time image-guided radiotherapy coupled to a linac-MR system, provided the fringe magnetic fields at their locations are below the determined tolerance levels. With the fringe magnetic fields of linac-MR systems expected to be larger than the tolerance

  3. CHARACTERISTICS OF SIGNALING PATHWAYS MEDIATING A CYTOTOXIC EFFECT OF DENDRITIC CELLS UPON ACTIVATED Т LYMPHOCYTES AND NK CELLS

    Directory of Open Access Journals (Sweden)

    T. V. Tyrinova

    2012-01-01

    Full Text Available Abstract. Cytotoxic/pro-apoptogenic effects of IFNα-induced dendritic cells (IFN-DCs directed against Т-lymphocytes and NK cells were investigated in healthy donors. Using an allogenic MLC system, it was revealed that IFN-DCs induce apoptosis of both activated CD4+ and CD8+ T-lymphocytes, and NK cells. Apoptosis of CD4+ and CD8+ T-lymphocytes induced by their interaction with IFN-DCs was mediated by various signaling pathways. In particular, activated CD4+Т-lymphocytes were most sensitive to TRAIL- и Fas/ FasL-transduction pathways, whereas activated CD8+ T-lymphocytes were induced to apoptosis via TNFα-mediated pathway. PD-1/B7-H1-signaling pathway also played a distinct role in cytotoxic activity of IFNDCs towards both types of T lymphocytes and activated NK cells. The pro-apoptogenic/cytotoxic activity of IFN-DC against activated lymphocytes may be regarded as a mechanism of a feedback regulation aimed at restriction of immune response and maintenance of immune homeostasis. Moreover, upregulation of proapoptogenic molecules on DCs under pathological conditions may lead to suppression of antigen-specific response, thus contributing to the disease progression.

  4. A method for testing the performance and the accuracy of the binary MLC used in helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Lissner, Steffen; Schubert, Kai; Klueter, Sebastian; Oetzel, Dieter; Debus, Juergen [University Hospital Heidelberg (Germany). Dept. of Radiation Oncology

    2013-08-01

    During a helical tomotherapy a binary MLC is used for fluence modulation. The 64 pneumatically driven leaves of the MLC are either completely open or closed. Th e fast and frequent leaf movements result in a high demand of accuracy and stability of the MLC. This article is based on the analytical investigation of the accuracy and the stability of the MLC. Different patterns of MLC movements were generated to investigate the characteristics of the MLC. One of the considered aspects contains the friction between the leaves. The influence of variations of the compressed air on the MLC was also explored. The integrated MVCT detector of the tomotherapy system deposits the treatment data in a matrix. The detector is triggered with the linear accelerator, which is pulsed by 300Hz. The data matrix is available after the treatment. An IDL (Interactive Data Language) routine was programmed in order to analyse the matrix. The points of time, at which the leaves open (POT), and the period, in which the leaves stay open (LOT), were measured and compared with the desired values. That procedure has been repeated several times a week for approximately 6 months to investigate the stability of the MLC. Relative deviations of the LOT from -0.4% to -5.4% were measured. The friction between the leaves had no significant influence on the LOT. The available compressed air, that is used to move the leaves, depends on the number of moving leaves and also on the previous movements of the MLC. Variations of the compressed air resulted in deviations of the LOT from -1.8% to -3.7%. The measured POT deviates from the programmed POT up to -18.4ms {+-} 0.7ms. This maximal deviation correlates with a shift of the gantry angle of 0.52 which is negligible. The MLC has shown a stable behaviour over the 6 months. A separate consideration of the leaves showed no higher standard deviation of the LOT than {+-} 0.7ms during the investigated time. The variation between the different leaves is much higher

  5. A method for testing the performance and the accuracy of the binary MLC used in helical tomotherapy

    International Nuclear Information System (INIS)

    Lissner, Steffen; Schubert, Kai; Klueter, Sebastian; Oetzel, Dieter; Debus, Juergen

    2013-01-01

    During a helical tomotherapy a binary MLC is used for fluence modulation. The 64 pneumatically driven leaves of the MLC are either completely open or closed. Th e fast and frequent leaf movements result in a high demand of accuracy and stability of the MLC. This article is based on the analytical investigation of the accuracy and the stability of the MLC. Different patterns of MLC movements were generated to investigate the characteristics of the MLC. One of the considered aspects contains the friction between the leaves. The influence of variations of the compressed air on the MLC was also explored. The integrated MVCT detector of the tomotherapy system deposits the treatment data in a matrix. The detector is triggered with the linear accelerator, which is pulsed by 300Hz. The data matrix is available after the treatment. An IDL (Interactive Data Language) routine was programmed in order to analyse the matrix. The points of time, at which the leaves open (POT), and the period, in which the leaves stay open (LOT), were measured and compared with the desired values. That procedure has been repeated several times a week for approximately 6 months to investigate the stability of the MLC. Relative deviations of the LOT from -0.4% to -5.4% were measured. The friction between the leaves had no significant influence on the LOT. The available compressed air, that is used to move the leaves, depends on the number of moving leaves and also on the previous movements of the MLC. Variations of the compressed air resulted in deviations of the LOT from -1.8% to -3.7%. The measured POT deviates from the programmed POT up to -18.4ms ± 0.7ms. This maximal deviation correlates with a shift of the gantry angle of 0.52 which is negligible. The MLC has shown a stable behaviour over the 6 months. A separate consideration of the leaves showed no higher standard deviation of the LOT than ± 0.7ms during the investigated time. The variation between the different leaves is much higher than

  6. Lymphocyte interactions with the extracellular matrix of malignant cells in vítro: A morphological and immunocytochemical study

    OpenAIRE

    Logothetou-Rella, H.

    1993-01-01

    The interactions of lymphocytes with the glycosaminoglycans-protease-membrane extracellular matrix, produced by mixed cell cultures of normal with malignant cell clones, were examined. Pre-activated and activated heterologous peripheral lymphocytes were used. Co-cultures of activated lymphocytes with al1 cell types used, formed identical cell nodules. Histology of cell nodules showed that activated lymphocytes were cytolytic to pure normal or malignant cell clo...

  7. SU-E-T-430: Modeling MLC Leaf End in 2D for Sliding Window IMRT and Arc Therapy

    International Nuclear Information System (INIS)

    Liang, X; Zhu, T

    2014-01-01

    Purpose: To develop a 2D geometric model for MLC accounting for leaf end dose leakage for dynamic IMRT and Rapidarc therapy. Methods: Leaf-end dose leakage is one of the problems for MLC dose calculation and modeling. Dosimetric leaf gap used to model the MLC and to count for leakage in dose calculation, but may not be accurate for smaller leaf gaps. We propose another geometric modeling method to compensate for the MLC round-shape leaf ends dose leakage, and improve the accuracy of dose calculation and dose verification. A triangular function is used to geometrically model the MLC leaf end leakage in the leaf motion direction, and a step function is used in the perpendicular direction. Dose measurements with different leaf gap, different window width, and different window height were conducted, and the results were used to fit the analytical model to get the model parameters. Results: Analytical models have been obtained for stop-and-shoot and dynamic modes for MLC motion. Parameters a=0.4, lw'=5.0 mm for 6X and a=0.54, lw'=4.1 mm for 15x were obtained from the fitting process. The proposed MLC leaf end model improves the dose profile at the two ends of the sliding window opening. This improvement is especially significant for smaller sliding window openings, which are commonly used for highly modulated IMRT plans and arc therapy plans. Conclusion: This work models the MLC round leaf end shape and movement pattern for IMRT dose calculation. The theory, as well as the results in this work provides a useful tool for photon beam IMRT dose calculation and verification

  8. Validation of dynamic MLC-controller log files using a two-dimensional diode array

    International Nuclear Information System (INIS)

    Li, Jonathan G.; Dempsey, James F.; Ding Li; Liu, Chihray; Palta, Jatinder R.

    2003-01-01

    Intensity-modulated radiation therapy (IMRT) delivered with multi-leaf collimator (MLC) in the step-and-shoot mode uses multiple static MLC segments to achieve intensity modulation. For typical IMRT treatment plans, significant numbers of segments are delivered with monitor units (MUs) of much less than 10. Verification of the ability of the linear accelerator (linac) to deliver small MU segments accurately is an important step in the IMRT commissioning and quality assurance (QA) process. Recent studies have reported large discrepancies between the intended and delivered segment MUs. These discrepancies could potentially cause large errors in the delivered patient dose. We have undertaken a systematic study to evaluate the accuracy of the dynamic MLC log files, which are created automatically by our commercial MLC workstation after each delivery, in recording the fractional MU delivered in the step-and-shoot mode. Two linac models were evaluated with simple-geometry leaf sequences and delivered with different total MUs and different nominal dose rates. A commercial two-dimensional diode array was used for the measurement. Large discrepancies between the intended and delivered segment MUs were found. The discrepancies were larger for small MU segments at higher dose rate, with some small MU segments completely undelivered. The recorded fractional MUs in the log files were found to agree with what was delivered within the limits of our experimental uncertainty. Our results indicate that it is important to verify the delivery accuracy of small MU segments that could potentially occur in a patient treatment and that the log files are useful in checking the integrity of the linac delivery once validated. Thus validated log files can be used as a QA tool for general IMRT delivery and patient-specific plan verification

  9. SU-E-T-471: Small Field Jaw/MLC Reference Data

    International Nuclear Information System (INIS)

    Kerns, J; Alvarez, P; Followill, D; Lowenstein, J; Molineu, A; Summers, P; Kry, S

    2014-01-01

    Purpose: In recent years the need for small field data of MLCs has increased due to the use of intensity-modulated radiation (IMRT), but moreover the use of stereotactic body radiation (SBRT) has increased, which uses not simply small field sizes, but small jaw and field sizes together. Having reference data for these small fields that is reliable would be invaluable to the physics community. Our study has gathered these values and the data distributions from the Radiological Physics Center's (RPC) site visits between 1990 and the present. Methods: For all measurements, the RPC used a 25 × 25 × 25cm water phantom placed at 100cm SSD. All measurements were made with an Exradin A16 cylindrical ion chamber at an effective depth of 10 cm. A total of 42 Varian machine measurements were used to compose the data for a 6 MV beam and 5 TrueBeam 6 MV flattening filter free (FFF) beams were used for FFF data. Results: Jaw/MLC fields were measured for both 6 MV and 6 MF FFF beams with the jaws and MLCs both at the following field sizes: 6×6, 4×4, 3×3, and 2×2cm. Measurements were normalized to the 10×10 field readings (defined by the jaws and MLC). Spread in the data was minimal and demonstrates a high level of accuracy of acquired data. Conclusion: Small field Jaw/MLC reference data for Varian 6MV and 6 MV FFF beams has been analyzed and presented here, composed of the aggregation of numerous RPC site visits. Obtaining reliable small field data remains difficult, however the RPC has collected high fidelity small field Jaw/MLC data. The data are presented as a reference along with their distributions, in such a way that the physicist can act based upon their own desired agreement with the reference data

  10. On the suitability of Elekta’s Agility 160 MLC for tracked radiation delivery: closed-loop machine performance

    International Nuclear Information System (INIS)

    Glitzner, M; Crijns, S P M; De Senneville, B Denis; Lagendijk, J J W; Raaymakers, B W

    2015-01-01

    For motion adaptive radiotherapy, dynamic multileaf collimator tracking can be employed to reduce treatment margins by steering the beam according to the organ motion. The Elekta Agility 160 MLC has hitherto not been evaluated for its tracking suitability. Both dosimetric performance and latency are key figures and need to be assessed generically, independent of the used motion sensor. In this paper, we propose the use of harmonic functions directly fed to the MLC to determine its latency during continuous motion. Furthermore, a control variable is extracted from a camera system and fed to the MLC. Using this setup, film dosimetry and subsequent γ statistics are performed, evaluating the response when tracking (MRI)-based physiologic motion in a closed-loop. The delay attributed to the MLC itself was shown to be a minor contributor to the overall feedback chain as compared to the impact of imaging components such as MRI sequences. Delay showed a linear phase behaviour of the MLC employed in continuously dynamic applications, which enables a general MLC-characterization. Using the exemplary feedback chain, dosimetry showed a vast increase in pass rate employing γ statistics. In this early stage, the tracking performance of the Agility using the test bench yielded promising results, making the technique eligible for translation to tracking using clinical imaging modalities. (paper)

  11. Poster - 53: Improving inter-linac DMLC IMRT dose precision by fine tuning of MLC leaf calibration

    International Nuclear Information System (INIS)

    Nakonechny, Keith; Tran, Muoi; Sasaki, David; Beck, James; Poirier, Yannick; Malkoske, Kyle

    2016-01-01

    Purpose: To develop a method to improve the inter-linac precision of DMLC IMRT dosimetry. Methods: The distance between opposing MLC leaf banks (“gap size”) can be finely tuned on Varian linacs. The dosimetric effect due to small deviations from the nominal gap size (“gap error”) was studied by introducing known errors for several DMLC sliding gap sizes, and for clinical plans based on the TG119 test cases. The plans were delivered on a single Varian linac and the relationship between gap error and the corresponding change in dose was measured. The plans were also delivered on eight Varian 2100 series linacs (at two institutions) in order to quantify the inter-linac variation in dose before and after fine tuning the MLC calibration. Results: The measured dose differences for each field agreed well with the predictions of LoSasso et al. Using the default MLC calibration, the variation in the physical MLC gap size was determined to be less than 0.4 mm between all linacs studied. The dose difference between the linacs with the largest and smallest physical gap was up to 5.4% (spinal cord region of the head and neck TG119 test case). This difference was reduced to 2.5% after fine tuning the MLC gap calibration. Conclusions: The inter-linac dose precision for DMLC IMRT on Varian linacs can be improved using a simple modification of the MLC calibration procedure that involves fine adjustment of the nominal gap size.

  12. Poster - 53: Improving inter-linac DMLC IMRT dose precision by fine tuning of MLC leaf calibration

    Energy Technology Data Exchange (ETDEWEB)

    Nakonechny, Keith; Tran, Muoi; Sasaki, David; Beck, James; Poirier, Yannick; Malkoske, Kyle [Simcoe-Muskoka Regional Cancer Centre (Canada)

    2016-08-15

    Purpose: To develop a method to improve the inter-linac precision of DMLC IMRT dosimetry. Methods: The distance between opposing MLC leaf banks (“gap size”) can be finely tuned on Varian linacs. The dosimetric effect due to small deviations from the nominal gap size (“gap error”) was studied by introducing known errors for several DMLC sliding gap sizes, and for clinical plans based on the TG119 test cases. The plans were delivered on a single Varian linac and the relationship between gap error and the corresponding change in dose was measured. The plans were also delivered on eight Varian 2100 series linacs (at two institutions) in order to quantify the inter-linac variation in dose before and after fine tuning the MLC calibration. Results: The measured dose differences for each field agreed well with the predictions of LoSasso et al. Using the default MLC calibration, the variation in the physical MLC gap size was determined to be less than 0.4 mm between all linacs studied. The dose difference between the linacs with the largest and smallest physical gap was up to 5.4% (spinal cord region of the head and neck TG119 test case). This difference was reduced to 2.5% after fine tuning the MLC gap calibration. Conclusions: The inter-linac dose precision for DMLC IMRT on Varian linacs can be improved using a simple modification of the MLC calibration procedure that involves fine adjustment of the nominal gap size.

  13. TH-AB-202-02: Real-Time Verification and Error Detection for MLC Tracking Deliveries Using An Electronic Portal Imaging Device

    International Nuclear Information System (INIS)

    J Zwan, B; Colvill, E; Booth, J; J O’Connor, D; Keall, P; B Greer, P

    2016-01-01

    Purpose: The added complexity of the real-time adaptive multi-leaf collimator (MLC) tracking increases the likelihood of undetected MLC delivery errors. In this work we develop and test a system for real-time delivery verification and error detection for MLC tracking radiotherapy using an electronic portal imaging device (EPID). Methods: The delivery verification system relies on acquisition and real-time analysis of transit EPID image frames acquired at 8.41 fps. In-house software was developed to extract the MLC positions from each image frame. Three comparison metrics were used to verify the MLC positions in real-time: (1) field size, (2) field location and, (3) field shape. The delivery verification system was tested for 8 VMAT MLC tracking deliveries (4 prostate and 4 lung) where real patient target motion was reproduced using a Hexamotion motion stage and a Calypso system. Sensitivity and detection delay was quantified for various types of MLC and system errors. Results: For both the prostate and lung test deliveries the MLC-defined field size was measured with an accuracy of 1.25 cm 2 (1 SD). The field location was measured with an accuracy of 0.6 mm and 0.8 mm (1 SD) for lung and prostate respectively. Field location errors (i.e. tracking in wrong direction) with a magnitude of 3 mm were detected within 0.4 s of occurrence in the X direction and 0.8 s in the Y direction. Systematic MLC gap errors were detected as small as 3 mm. The method was not found to be sensitive to random MLC errors and individual MLC calibration errors up to 5 mm. Conclusion: EPID imaging may be used for independent real-time verification of MLC trajectories during MLC tracking deliveries. Thresholds have been determined for error detection and the system has been shown to be sensitive to a range of delivery errors.

  14. Fast leaf-fitting with generalized underdose/overdose constraints for real-time MLC tracking

    International Nuclear Information System (INIS)

    Moore, Douglas; Sawant, Amit; Ruan, Dan

    2016-01-01

    Purpose: Real-time multileaf collimator (MLC) tracking is a promising approach to the management of intrafractional tumor motion during thoracic and abdominal radiotherapy. MLC tracking is typically performed in two steps: transforming a planned MLC aperture in response to patient motion and refitting the leaves to the newly generated aperture. One of the challenges of this approach is the inability to faithfully reproduce the desired motion-adapted aperture. This work presents an optimization-based framework with which to solve this leaf-fitting problem in real-time. Methods: This optimization framework is designed to facilitate the determination of leaf positions in real-time while accounting for the trade-off between coverage of the PTV and avoidance of organs at risk (OARs). Derived within this framework, an algorithm is presented that can account for general linear transformations of the planned MLC aperture, particularly 3D translations and in-plane rotations. This algorithm, together with algorithms presented in Sawant et al. [“Management of three-dimensional intrafraction motion through real-time DMLC tracking,” Med. Phys. 35, 2050–2061 (2008)] and Ruan and Keall [Presented at the 2011 IEEE Power Engineering and Automation Conference (PEAM) (2011) (unpublished)], was applied to apertures derived from eight lung intensity modulated radiotherapy plans subjected to six-degree-of-freedom motion traces acquired from lung cancer patients using the kilovoltage intrafraction monitoring system developed at the University of Sydney. A quality-of-fit metric was defined, and each algorithm was evaluated in terms of quality-of-fit and computation time. Results: This algorithm is shown to perform leaf-fittings of apertures, each with 80 leaf pairs, in 0.226 ms on average as compared to 0.082 and 64.2 ms for the algorithms of Sawant et al., Ruan, and Keall, respectively. The algorithm shows approximately 12% improvement in quality-of-fit over the Sawant et al

  15. Independent dose calculation of the Tps Iplan in radiotherapy conformed with MLC

    International Nuclear Information System (INIS)

    Adrada, A.; Tello, Z.; Medina, L.; Garrigo, E.; Venencia, D.

    2014-08-01

    The systems utilization of independent dose calculation in three dimensional-Conformal Radiation Therapy (3D-Crt) treatments allows a direct verification of the treatments times. The utilization of these systems allows diminishing the probability of errors occurrence generated by the treatment planning system (Tps), allowing a detailed analysis of the dose to delivering and review of the normalization point (Np) or prescription. The independent dose calculation is realized across the knowledge of dosimetric parameters of the treatment machine and particular characteristics of every individual field. The aim of this work is develops a calculation system of punctual doses for isocentric fields conformed with multi-leaf collimation systems (MLC), where the dose calculation is in conformity with the suggested ones by ICRU Report No. 42, 1987. Calculation software was realized in C ++ under a free platform of programming (Code::Blocks). The system uses files in format Rtp, exported from the Tps to systems of record and verification (Lantis). This file contains detailed information of the dose, Um, position of the MLC sheets and collimators for every field of treatment. The size of equivalent field is obtained from the positions of every sheet; the effective depth of calculation can be introduced from the dosimetric report of the Tps or automatically from the DFS of the field. The 3D coordinates of the isocenter and the Np for the treatment plan must be introduced manually. From this information the system looks the dosimetric parameters and calculates the Um. The calculations were realized in two accelerators a NOVALIS Tx (Varian) with 120 sheets of high definition (hd-MLC) and a PRIMUS Optifocus (Siemens) with 82 sheets. 705 patients were analyzed for a total of 1082, in plans made for both equipment s, the average uncertainty with regard to the calculation of the Tps is-0.43% ± 2.42% in a range between [-7.90 %, 7.50 %]. The major uncertainty was in Np near of the

  16. Fast leaf-fitting with generalized underdose/overdose constraints for real-time MLC tracking

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Douglas, E-mail: douglas.moore@utsouthwestern.edu; Sawant, Amit [Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, Texas 75390 (United States); Ruan, Dan [Department of Radiation Oncology, University of California, Los Angeles, California 90095 (United States)

    2016-01-15

    Purpose: Real-time multileaf collimator (MLC) tracking is a promising approach to the management of intrafractional tumor motion during thoracic and abdominal radiotherapy. MLC tracking is typically performed in two steps: transforming a planned MLC aperture in response to patient motion and refitting the leaves to the newly generated aperture. One of the challenges of this approach is the inability to faithfully reproduce the desired motion-adapted aperture. This work presents an optimization-based framework with which to solve this leaf-fitting problem in real-time. Methods: This optimization framework is designed to facilitate the determination of leaf positions in real-time while accounting for the trade-off between coverage of the PTV and avoidance of organs at risk (OARs). Derived within this framework, an algorithm is presented that can account for general linear transformations of the planned MLC aperture, particularly 3D translations and in-plane rotations. This algorithm, together with algorithms presented in Sawant et al. [“Management of three-dimensional intrafraction motion through real-time DMLC tracking,” Med. Phys. 35, 2050–2061 (2008)] and Ruan and Keall [Presented at the 2011 IEEE Power Engineering and Automation Conference (PEAM) (2011) (unpublished)], was applied to apertures derived from eight lung intensity modulated radiotherapy plans subjected to six-degree-of-freedom motion traces acquired from lung cancer patients using the kilovoltage intrafraction monitoring system developed at the University of Sydney. A quality-of-fit metric was defined, and each algorithm was evaluated in terms of quality-of-fit and computation time. Results: This algorithm is shown to perform leaf-fittings of apertures, each with 80 leaf pairs, in 0.226 ms on average as compared to 0.082 and 64.2 ms for the algorithms of Sawant et al., Ruan, and Keall, respectively. The algorithm shows approximately 12% improvement in quality-of-fit over the Sawant et al

  17. SU-E-T-646: Quality Assurance of Truebeam Multi-Leaf Collimator Using a MLC QA Phantom

    International Nuclear Information System (INIS)

    Zhang, J; Lu, J; Hong, D

    2015-01-01

    Purpose: To perform a routine quality assurance procedure for Truebeam multi-leaf collimator (MLC) using MLC QA phantom, verify the stability and reliability of MLC during the treatment. Methods: MLC QA phantom is a specialized phantom for MLC quality assurance (QA), and contains five radio-opaque spheres that are embedded in an “L” shape. The phantom was placed isocentrically on the Truebeam treatment couch for the tests. A quality assurance plan was setted up in the Eclipse v10.0, the fields that need to be delivered in order to acquire the necessary images, the MLC shapes can then be obtained by the images. The images acquired by the electronic portal imaging device (EPID), and imported into the PIPSpro software for the analysis. The tests were delivered twelve weeks (once a week) to verify consistency of the delivery, and the images are acquired in the same manner each time. Results: For the Leaf position test, the average position error was 0.23mm±0.02mm (range: 0.18mm∼0.25mm). The Leaf width was measured at the isocenter, the average error was 0.06mm±0.02mm (range: 0.02mm∼0.08mm) for the Leaf width test. Multi-Port test showed the dynamic leaf shift error, the average error was 0.28mm±0.03mm (range: 0.2mm∼0.35mm). For the leaf transmission test, the average inter-leaf leakage value was 1.0%±0.17% (range: 0.8%∼1.3%) and the average inter-bank leakage value was 32.6%±2.1% (range: 30.2%∼36.1%). Conclusion: By the test of 12 weeks, the MLC system of the Truebeam is running in a good condition and the MLC system can be steadily and reliably carried out during the treatment. The MLC QA phantom is a useful test tool for the MLC QA

  18. Robot system for preparing lymphocyte chromosome

    International Nuclear Information System (INIS)

    Hayata, Isamu; Furukawa, Akira; Yamamoto, Mikio; Sato, Koki; Tabuchi, Hiroyoshi; Okabe, Nobuo.

    1992-01-01

    Towards the automatization of the scoring of chromosome aberrations in radiation dosimetry with the emphasis on the improvement of biological preparations, the conventional culture and harvesting method was modified. Based on this modified method, a culture and harvest robotic system (CHROSY) for preparing lymphocyte chromosome was developed. The targeted points of the modification are as in the preparing lymphocyte chromosome was developed. The targeted points of the modification are as in the following. 1) Starting culture with purified lymphocytes in a fixed cell number. 2) Avoiding the loss of cells in changing the liquids following centrifugalization. 3) Keeping the quantity of the liquids to be applied to the treatments of cells fixed. 4) Building a system even a beginner can handle. System features are as follows. 1) Operation system: Handling robot having 5 degrees of freedom; a rotator incubator with an automatic sliding door; units for setting and removing pipette tips; a centrifuge equipped with a position adjuster and an automatic sliding door; two aluminium block baths; two nozzles as pipettes and aspirators connected to air pumps; a capping unit with a nozzle for CO 2 gas; a compressor; and an air manipulated syringe. 2) Control system; NEC PC-9801RX21 with CRT; and program written in Basic and Assembly languages on MS-DOS. It took this system 2 hours and 25 minutes to harvest 2 cultures. A fairly good chromosome slide was made from the sample harvested by CHROSY automatically. (author)

  19. Chemokines, lymphocytes, and HIV

    Directory of Open Access Journals (Sweden)

    Farber J.M.

    1998-01-01

    Full Text Available Chemokines are members of a family of more than 30 human cytokines whose best-described activities are as chemotactic factors for leukocytes and that are presumed to be important in leukocyte recruitment and trafficking. While many chemokines can act on lymphocytes, the roles of chemokines and their receptors in lymphocyte biology are poorly understood. The recent discoveries that chemokines can suppress infection by HIV-1 and that chemokine receptors serve, along with CD4, as obligate co-receptors for HIV-1 entry have lent urgency to studies on the relationships between chemokines and lymphocytes. My laboratory has characterized Mig and Crg-2/IP-10, chemokines that are induced by IFN-g and that specifically target lymphocytes, particularly activated T cells. We have demonstrated that the genes for these chemokines are widely expressed during experimental infections in mice with protozoan and viral pathogens, but that the patterns of mig and crg-2 expression differed, suggesting non-redundant roles in vivo. Our related studies to identify new chemokine receptors from activated lymphocytes resulted in the cloning of STRL22 and STRL33. We and others have shown that STRL22 is a receptor for the CC chemokine MIP-3a, and STRL22 has been re-named CCR6. Although STRL33 remains an orphan receptor, we have shown that it can function as a co-receptor for HIV-1 envelope glycoproteins, and that it is active with a broader range of HIV-1 envelope glycoproteins than the major co-receptors described to date. The ability of STRL33 to function with a wide variety of envelope glycoproteins may become particularly important if therapies are instituted to block other specific co-receptors. We presume that investigations into the roles of chemokines and their receptors in lymphocyte biology will provide information important for understanding the pathogenesis of AIDS and for manipulating immune and inflammatory responses for clinical benefit

  20. SU-E-T-506: Dosimetric Verification of Photon MLC Delivered Electron Fields for Implementing MERT On An Artiste Linac

    International Nuclear Information System (INIS)

    Jin, L; Eldib, A; Li, J; Wang, L; Ma, C; Fan, J

    2014-01-01

    Purpose: To verify the dose accuracy of photon MLC delivered electron fields for implementing energy-intensity modulated electron radiotherapy (MERT) on an Artiste linac. Methods: It was proposed to deliver MERT on an Artiste linac at a short SSD (60 cm) to reduce beam penumbra caused by electron scatters. An in-house developed Monte Carlo (MC)-based dose calculation/optimization planning code was used for treatment planning. Our previous study showed that the measured dose distribution of a breast plan showed good agreement with the calculations in low-medium dose regions while the differences in high dose regions were outstanding. A continuous work found that the discrepancy is mainly caused by improper modeling in MC for the single focused MLC in the Artiste which was simplified as double focused in the previous MC simulations. With this remodeled MLC in the calculations, an energy-intensity modulated electron plan using 6, 9, 12 and 15 MeV was generated for a breast treatment on a breast phantom at a 60 cm SSD and recalculated regarding a solid water phantom. For a test study, four of MLC segments (each with a different energy) generated in the plan were delivered to the phantom and a film measurement was performed at the depth of 2 cm. The measured 2D dose distribution was then compared with calculations. Results: For composite doses of the four segments, measured 2D dose distributions overall agree well with the calculations (3mm/3%) in most area. The separate measurement for a single MLC segment for each of energies also showed the consistence with the calculations. Conclusion: After remodeling MLC in the MC calculations, the measured dose distribution for a subset of MLC segments from a MERT plan showed good agreement. Further detailed verification for the full plan will be the work in the next step

  1. Culture.

    Science.gov (United States)

    Smith, Timothy B; Rodríguez, Melanie Domenech; Bernal, Guillermo

    2011-02-01

    This article summarizes the definitions, means, and research of adapting psychotherapy to clients' cultural backgrounds. We begin by reviewing the prevailing definitions of cultural adaptation and providing a clinical example. We present an original meta-analysis of 65 experimental and quasi-experimental studies involving 8,620 participants. The omnibus effect size of d = .46 indicates that treatments specifically adapted for clients of color were moderately more effective with that clientele than traditional treatments. The most effective treatments tended to be those with greater numbers of cultural adaptations. Mental health services targeted to a specific cultural group were several times more effective than those provided to clients from a variety of cultural backgrounds. We recommend a series of research-supported therapeutic practices that account for clients' culture, with culture-specific treatments being more effective than generally culture-sensitive treatments. © 2010 Wiley Periodicals, Inc.

  2. Monoclonal antibodies to antigens on human neutrophils, activated T lymphocytes, and acute leukemia blast cells

    International Nuclear Information System (INIS)

    Miterev, G.Yu.; Burova, G.F.; Puzhitskaya, M.S.; Danilevich, S.V.; Bulycheva, T.I.

    1987-01-01

    The authors describe the production of two mouse hybridomas secreting monoclonal antibodies to antigenic determinants of the surface membranes of human neutrophils, activated T lymphocytes, and acute leukemic blast cells. The degree of lymphocyte stimulation was estimated from incorporation of 3 H-thymidine with parallel microculture. Monoclonal antibodies of supernatants of hybridoma cultures shown here reacted in both immunofluorescence test and cytotoxicity test with surface membrane antigens on the majority of neutrophils and PHA-activated peripheral blood lymphocytes from healthy subjects, but did not give positive reactions with unactivated lymphocytes, adherent monocytes, erythrocytes, and alloantigen-stimulated lymphocytes

  3. Monoclonal antibodies to antigens on human neutrophils, activated T lymphocytes, and acute leukemia blast cells

    Energy Technology Data Exchange (ETDEWEB)

    Miterev, G.Yu.; Burova, G.F.; Puzhitskaya, M.S.; Danilevich, S.V.; Bulycheva, T.I.

    1987-11-01

    The authors describe the production of two mouse hybridomas secreting monoclonal antibodies to antigenic determinants of the surface membranes of human neutrophils, activated T lymphocytes, and acute leukemic blast cells. The degree of lymphocyte stimulation was estimated from incorporation of /sup 3/H-thymidine with parallel microculture. Monoclonal antibodies of supernatants of hybridoma cultures shown here reacted in both immunofluorescence test and cytotoxicity test with surface membrane antigens on the majority of neutrophils and PHA-activated peripheral blood lymphocytes from healthy subjects, but did not give positive reactions with unactivated lymphocytes, adherent monocytes, erythrocytes, and alloantigen-stimulated lymphocytes.

  4. Stimulation of allogeneic lymphocytes by skin epidermal cells in the rat

    International Nuclear Information System (INIS)

    Tanaka, S.; Sakai, A.

    1979-01-01

    The ability of skin epidermal cells to induce allogeneic lymphocytes into proliferation was examined in mixed skin cell-lymphocyte culture reaction (MSLR). The stimulatng capacity of skin cells was reduced significantly by trypsin digestion, although the damage was repaired by incubation at 37 C for 3 hr. The optimal concentration of mitomycin C for treatment of stimulating cells in the MSLR differed from that in mixed lymphocyte culture reaction (MLR). Irradiation rendered them three to four times more stimulatory than did mitomycin C. Removal of adherent cells from responding cells by passage through a nylon-wool column gave a substantial elevation of the MSLR. The lymphocytes cocultured with skin cells in the primary MSLR incorporated 3 H-thymidine, with the peak at the 6th day of culture. If the lymphocytes primed in the MSLR were restimulated with skin cells from the same stimulating strain, the primed lymphocytes responded promptly and in great magnitude

  5. Kinetics of human lymphocyte division and chromosomal radiosensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, N O; Bianchi, M S; Larramendy, M [Instituto Multidisciplinario de Biologia Celular, La Plata (Argentinia)

    1979-12-01

    Human blood from normal donors was irradiated with 200 R during the G/sub 0/ phase, and the X-ray sensitivity of early and late dividing lymphocytes in culture was expressed as percentage of induced dicentrics. Cells in first or subsequent divisions were individualized by BrdU-Giemsa techniques. Lymphocytes in the first division at 40, 44 and 72 h after the start of culture had a lower sensitivity to radiation than lymphocytes making their first division at 48, 52 and 56 h. It was observed that: (a) the combination of radiation followed by BrdU did not increase the clastoyenic action of X-rays, (b)X-rays in the dose and duration used in our cultures did not increase the frequency of SCEs, and (c) minor changes in culture conditions probably influenced the frequency of SCEs.

  6. Regional and systemic distribution of anti-tumor x anti-CD3 heteroaggregate antibodies and cultured human peripheral blood lymphocytes in a human colon cancer xenograft

    International Nuclear Information System (INIS)

    Nelson, H.; Ramsey, P.S.; Kerr, L.A.; McKean, D.J.; Donohue, J.H.

    1990-01-01

    Anti-tumor antibody (317G5) covalently coupled to an anti-CD3 antibody (OKT3) produces a heteroaggregate (HA) antibody that can target PBL to lyse tumor cells expressing the appropriate tumor Ag. The i.v. and i.p. distribution of radiolabeled HA antibody 317G5 x OKT3 and of radiolabeled cultured human PBL were studied in athymic nude mice bearing solid intraperitoneal tumor established from the human colon tumor line, LS174T. Mice were injected with 125I-labeled HA antibody, 125I-labeled anti-tumor mAb, or 111In-labeled PBL, and at designated timepoints tissues were harvested and measured for radioactivity. 125I-317G5 x OKT3 localized specifically to tumor sites. Tumor radioactivity levels (percent injected dose/gram) were lower with 125I-317G5 x OKT3 HA antibody than with 125I-317G5 anti-tumor mAb, but were similar to levels reported for other anti-tumor mAb. The major difference in radioactivity levels observed between i.v. and i.p. administration of 125I-317G5 x OKT3 was an increase in hepatic radioactivity after i.v. HA antibody administration. HA antibodies produced from F(ab')2 fragments, which exhibit decreased m. w. and decreased Fc receptor-mediated binding, demonstrated improved tumor:tissue ratios as compared to intact antibody HA. 125I-317G5 F(ab')2 x OKT3 F(ab')2 antibody levels were equivalent to intact HA antibody levels in tumor, but were lower than intact HA antibody levels in the blood, bowel, and liver. Tumor:bowel ratios (20:1 at 48 h) were highest when 317G5 F(ab')2 x OKT3 F(ab')2 was injected i.p. Autoradiography confirmed that anti-tumor x anti-CD3 HA antibodies localized specifically to intraperitoneal tumor; that i.p. administered HA antibodies penetrated tumor directly; and that i.v. administered HA antibodies distributed along tumor vasculature

  7. SU-E-J-67: Evaluation of Adaptive MLC Morphing for Online Correction of Prostate Cancer Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sandhu, R; Qin, A; Yan, D [William Beaumont Hospital, Royal Oak, MI (United States)

    2015-06-15

    Purpose: Online adaptive MLC morphing is desirable over translational couch shifts to accommodate target position as well as anatomic changes. A reliable method of adaptive MLC segment to target during prostate cancer IMRT treatment is proposed and evaluated by comparison with daily online-image guidance (IGRT) correction and online-IMRT planning. Methods: The MLC adaptive algorithm involves following steps; move the MLC segments according to target translational shifts, and then morph the segment shape to maintain the spatial relationship between the planning-target contour and MLC segment. Efficacy of this method was evaluated retrospectively using daily-CBCT images on seven prostate patients treated with seven-beam IMRT treatment to deliver 64Gy in 20 fractions. Daily modification was simulated with three approaches; daily-IGRT correction based on implanted radio-markers, adaptive MLC morphing, and online-IMRT planning, with no-residual variation. The selected dosimetric endpoints and nEUD (normalized equivalent uniform dose to online-IMRT planning) of each organ of interest were determined for evaluation and comparison. Results: For target(prostate), bladder and rectal-wall, the mean±sd of nEUD were 97.6%+3.2%, 103.9%±4.9% and 97.4%±1.1% for daily-IGRT correction; and 100.2%+0.2%, 108.9%±5.1% and 99.8%±1.2% for adaptive MLC morphing, respectively. For daily-IGRT correction, adaptive MLC morphing and online-IMRT planning, target D99 was <95% of the prescription dose in 30%, 0% and 0% of 140 fractions, respectively. For the rectal-wall, D5 exceeded 105% of the planned-D5 in 2.8%, 11.4% and 0% of 140 fractions, respectively. For the bladder, Dmax exceeded 105% of the planned-D5 in 2.8%, 5.6% and 0% of 140 fractions, respectively. D30 of bladder and rectal-wall were well within the planned-D30 for all three approaches. Conclusion: The proposed method of adaptive MLC morphing can be beneficial for the prostate patient population with large deformation and

  8. The dosimetric impact of inversely optimized arc radiotherapy plan modulation for real-time dynamic MLC tracking delivery

    International Nuclear Information System (INIS)

    Falk, Marianne; Larsson, Tobias; Keall, Paul; Chul Cho, Byung; Aznar, Marianne; Korreman, Stine; Poulsen, Per; Munck af Rosenschoeld, Per

    2012-01-01

    Purpose: Real-time dynamic multileaf collimator (MLC) tracking for management of intrafraction tumor motion can be challenging for highly modulated beams, as the leaves need to travel far to adjust for target motion perpendicular to the leaf travel direction. The plan modulation can be reduced by using a leaf position constraint (LPC) that reduces the difference in the position of adjacent MLC leaves in the plan. The purpose of this study was to investigate the impact of the LPC on the quality of inversely optimized arc radiotherapy plans and the effect of the MLC motion pattern on the dosimetric accuracy of MLC tracking delivery. Specifically, the possibility of predicting the accuracy of MLC tracking delivery based on the plan modulation was investigated. Methods: Inversely optimized arc radiotherapy plans were created on CT-data of three lung cancer patients. For each case, five plans with a single 358 deg. arc were generated with LPC priorities of 0 (no LPC), 0.25, 0.5, 0.75, and 1 (highest possible LPC), respectively. All the plans had a prescribed dose of 2 Gy x 30, used 6 MV, a maximum dose rate of 600 MU/min and a collimator angle of 45 deg. or 315 deg. To quantify the plan modulation, an average adjacent leaf distance (ALD) was calculated by averaging the mean adjacent leaf distance for each control point. The linear relationship between the plan quality [i.e., the calculated dose distributions and the number of monitor units (MU)] and the LPC was investigated, and the linear regression coefficient as well as a two tailed confidence level of 95% was used in the evaluation. The effect of the plan modulation on the performance of MLC tracking was tested by delivering the plans to a cylindrical diode array phantom moving with sinusoidal motion in the superior-inferior direction with a peak-to-peak displacement of 2 cm and a cycle time of 6 s. The delivery was adjusted to the target motion using MLC tracking, guided in real-time by an infrared optical system

  9. SU-E-J-67: Evaluation of Adaptive MLC Morphing for Online Correction of Prostate Cancer Radiotherapy

    International Nuclear Information System (INIS)

    Sandhu, R; Qin, A; Yan, D

    2015-01-01

    Purpose: Online adaptive MLC morphing is desirable over translational couch shifts to accommodate target position as well as anatomic changes. A reliable method of adaptive MLC segment to target during prostate cancer IMRT treatment is proposed and evaluated by comparison with daily online-image guidance (IGRT) correction and online-IMRT planning. Methods: The MLC adaptive algorithm involves following steps; move the MLC segments according to target translational shifts, and then morph the segment shape to maintain the spatial relationship between the planning-target contour and MLC segment. Efficacy of this method was evaluated retrospectively using daily-CBCT images on seven prostate patients treated with seven-beam IMRT treatment to deliver 64Gy in 20 fractions. Daily modification was simulated with three approaches; daily-IGRT correction based on implanted radio-markers, adaptive MLC morphing, and online-IMRT planning, with no-residual variation. The selected dosimetric endpoints and nEUD (normalized equivalent uniform dose to online-IMRT planning) of each organ of interest were determined for evaluation and comparison. Results: For target(prostate), bladder and rectal-wall, the mean±sd of nEUD were 97.6%+3.2%, 103.9%±4.9% and 97.4%±1.1% for daily-IGRT correction; and 100.2%+0.2%, 108.9%±5.1% and 99.8%±1.2% for adaptive MLC morphing, respectively. For daily-IGRT correction, adaptive MLC morphing and online-IMRT planning, target D99 was <95% of the prescription dose in 30%, 0% and 0% of 140 fractions, respectively. For the rectal-wall, D5 exceeded 105% of the planned-D5 in 2.8%, 11.4% and 0% of 140 fractions, respectively. For the bladder, Dmax exceeded 105% of the planned-D5 in 2.8%, 5.6% and 0% of 140 fractions, respectively. D30 of bladder and rectal-wall were well within the planned-D30 for all three approaches. Conclusion: The proposed method of adaptive MLC morphing can be beneficial for the prostate patient population with large deformation and

  10. Acute Lymphocytic Leukemia

    Science.gov (United States)

    ... that may increase the risk of acute lymphocytic leukemia include: Previous cancer treatment. Children and adults who've had certain types of chemotherapy and radiation therapy for other kinds of cancer may have an increased ... leukemia. Exposure to radiation. People exposed to very high ...

  11. Effectiveness and Safety of MLC601 in the Treatment of Mild to Moderate Alzheimer's Disease: A Multicenter, Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Hossein Pakdaman

    2015-03-01

    Full Text Available Background: MLC601 is a possible modulator of amyloid precursor protein processing, and in a clinical trial study MLC601 showed some effectiveness in cognitive function in Alzheimer's disease (AD patients. We aimed to evaluate the effectiveness and safety of MLC601 in the treatment of mild to moderate AD as compared to 3 approved cholinesterase inhibitors (ChEIs including donepezil, rivastigmine and galantamine. Methods: In a multicenter, nonblinded, randomized controlled trial, 264 volunteers with AD were randomly divided into 4 groups of 66; groups 1, 2, 3 and 4 received donepezil, rivastigmine, MLC601 and galantamine, respectively. Subjects underwent a clinical diagnostic interview and a cognitive/functional battery including the Mini-Mental State Examination (MMSE and Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog. Patients were visited every 4 months, and the score of cognition was recorded by the neurologists. Results: There were no significant differences in age, sex, marital status and baseline score of cognition among the 4 groups. In total, 39 patients (14.7% left the study. Trend of cognition changes based on the modifications over the time for MMSE and ADAS-cog scores did not differ significantly among groups (p = 0.92 for MMSE and p = 0.87 for ADAS-Cog. Conclusion: MLC601 showed a promising safety profile and also efficacy compared to 3 FDA-approved ChEIs.

  12. An EPID response calculation algorithm using spatial beam characteristics of primary, head scattered and MLC transmitted radiation

    International Nuclear Information System (INIS)

    Rosca, Florin; Zygmanski, Piotr

    2008-01-01

    We have developed an independent algorithm for the prediction of electronic portal imaging device (EPID) response. The algorithm uses a set of images [open beam, closed multileaf collimator (MLC), various fence and modified sweeping gap patterns] to separately characterize the primary and head-scatter contributions to EPID response. It also characterizes the relevant dosimetric properties of the MLC: Transmission, dosimetric gap, MLC scatter [P. Zygmansky et al., J. Appl. Clin. Med. Phys. 8(4) (2007)], inter-leaf leakage, and tongue and groove [F. Lorenz et al., Phys. Med. Biol. 52, 5985-5999 (2007)]. The primary radiation is modeled with a single Gaussian distribution defined at the target position, while the head-scatter radiation is modeled with a triple Gaussian distribution defined downstream of the target. The distances between the target and the head-scatter source, jaws, and MLC are model parameters. The scatter associated with the EPID is implicit in the model. Open beam images are predicted to within 1% of the maximum value across the image. Other MLC test patterns and intensity-modulated radiation therapy fluences are predicted to within 1.5% of the maximum value. The presented method was applied to the Varian aS500 EPID but is designed to work with any planar detector with sufficient spatial resolution

  13. Determination of the optimal tolerance for MLC positioning in sliding window and VMAT techniques

    International Nuclear Information System (INIS)

    Hernandez, V.; Abella, R.; Calvo, J. F.; Jurado-Bruggemann, D.; Sancho, I.; Carrasco, P.

    2015-01-01

    Purpose: Several authors have recommended a 2 mm tolerance for multileaf collimator (MLC) positioning in sliding window treatments. In volumetric modulated arc therapy (VMAT) treatments, however, the optimal tolerance for MLC positioning remains unknown. In this paper, the authors present the results of a multicenter study to determine the optimal tolerance for both techniques. Methods: The procedure used is based on dynalog file analysis. The study was carried out using seven Varian linear accelerators from five different centers. Dynalogs were collected from over 100 000 clinical treatments and in-house software was used to compute the number of tolerance faults as a function of the user-defined tolerance. Thus, the optimal value for this tolerance, defined as the lowest achievable value, was investigated. Results: Dynalog files accurately predict the number of tolerance faults as a function of the tolerance value, especially for low fault incidences. All MLCs behaved similarly and the Millennium120 and the HD120 models yielded comparable results. In sliding window techniques, the number of beams with an incidence of hold-offs >1% rapidly decreases for a tolerance of 1.5 mm. In VMAT techniques, the number of tolerance faults sharply drops for tolerances around 2 mm. For a tolerance of 2.5 mm, less than 0.1% of the VMAT arcs presented tolerance faults. Conclusions: Dynalog analysis provides a feasible method for investigating the optimal tolerance for MLC positioning in dynamic fields. In sliding window treatments, the tolerance of 2 mm was found to be adequate, although it can be reduced to 1.5 mm. In VMAT treatments, the typically used 5 mm tolerance is excessively high. Instead, a tolerance of 2.5 mm is recommended

  14. SU-F-T-271: Comparing IMRT QA Pass Rates Before and After MLC Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Mazza, A; Perrin, D; Fontenot, J [Mary Bird Perkins Cancer Center, Baton Rouge, LA (United States)

    2016-06-15

    Purpose: To compare IMRT QA pass rates before and after an in-house MLC leaf calibration procedure. Methods: The MLC leaves and backup jaws on four Elekta linear accelerators with MLCi2 heads were calibrated using the EPID-based RIT Hancock Test as the means for evaluation. The MLCs were considered to be successfully calibrated when they could pass the Hancock Test with criteria of 1 mm jaw position tolerance, and 1 mm leaf position tolerance. IMRT QA results were collected pre- and postcalibration and analyzed using gamma analysis with 3%/3mm DTA criteria. AAPM TG-119 test plans were also compared pre- and post-calibration, at both 2%/2mm DTA and 3%/3mm DTA. Results: A weighted average was performed on the results for all four linear accelerators. The pre-calibration IMRT QA pass rate was 98.3 ± 0.1%, compared with the post-calibration pass rate of 98.5 ± 0.1%. The TG-119 test plan results showed more of an improvement, particularly at the 2%/2mm criteria. The averaged results were 89.1% pre and 96.1% post for the C-shape plan, 94.8% pre and 97.1% post for the multi-target plan, 98.6% pre and 99.7% post for the prostate plan, 94.7% pre and 94.8% post for the head/neck plan. Conclusion: The patient QA results did not show statistically significant improvement at the 3%/3mm DTA criteria after the MLC calibration procedure. However, the TG-119 test cases did show significant improvement at the 2%/2mm level.

  15. Improving IMRT-plan quality with MLC leaf position refinement post plan optimization

    International Nuclear Information System (INIS)

    Niu Ying; Zhang Guowei; Berman, Barry L.; Parke, William C.; Yi Byongyong; Yu, Cedric X.

    2012-01-01

    Purpose: In intensity-modulated radiation therapy (IMRT) planning, reducing the pencil-beam size may lead to a significant improvement in dose conformity, but also increase the time needed for the dose calculation and plan optimization. The authors develop and evaluate a postoptimization refinement (POpR) method, which makes fine adjustments to the multileaf collimator (MLC) leaf positions after plan optimization, enhancing the spatial precision and improving the plan quality without a significant impact on the computational burden. Methods: The authors’ POpR method is implemented using a commercial treatment planning system based on direct aperture optimization. After an IMRT plan is optimized using pencil beams with regular pencil-beam step size, a greedy search is conducted by looping through all of the involved MLC leaves to see if moving the MLC leaf in or out by half of a pencil-beam step size will improve the objective function value. The half-sized pencil beams, which are used for updating dose distribution in the greedy search, are derived from the existing full-sized pencil beams without need for further pencil-beam dose calculations. A benchmark phantom case and a head-and-neck (HN) case are studied for testing the authors’ POpR method. Results: Using a benchmark phantom and a HN case, the authors have verified that their POpR method can be an efficient technique in the IMRT planning process. Effectiveness of POpR is confirmed by noting significant improvements in objective function values. Dosimetric benefits of POpR are comparable to those of using a finer pencil-beam size from the optimization start, but with far less computation and time. Conclusions: The POpR is a feasible and practical method to significantly improve IMRT-plan quality without compromising the planning efficiency.

  16. SU-F-T-465: Two Years of Radiotherapy Treatments Analyzed Through MLC Log Files

    Energy Technology Data Exchange (ETDEWEB)

    Defoor, D [University of Texas HSC SA, New Braunfles, TX (United States); Kabat, C; Papanikolaou, N [University of Texas HSC SA, San Antonio, TX (United States); Stathakis, S [Cancer Therapy and Research Center, San Antonio, TX (United States)

    2016-06-15

    Purpose: To present treatment statistics of a Varian Novalis Tx using more than 90,000 Varian Dynalog files collected over the past 2 years. Methods: Varian Dynalog files are recorded for every patient treated on our Varian Novalis Tx. The files are collected and analyzed daily to check interfraction agreement of treatment deliveries. This is accomplished by creating fluence maps from the data contained in the Dynalog files. From the Dynalog files we have also compiled statistics for treatment delivery times, MLC errors, gantry errors and collimator errors. Results: The mean treatment time for VMAT patients was 153 ± 86 seconds while the mean treatment time for step & shoot was 256 ± 149 seconds. Patient’s treatment times showed a variation of 0.4% over there treatment course for VMAT and 0.5% for step & shoot. The average field sizes were 40 cm2 and 26 cm2 for VMAT and step & shoot respectively. VMAT beams contained and average overall leaf travel of 34.17 meters and step & shoot beams averaged less than half of that at 15.93 meters. When comparing planned and delivered fluence maps generated using the Dynalog files VMAT plans showed an average gamma passing percentage of 99.85 ± 0.47. Step & shoot plans showed an average gamma passing percentage of 97.04 ± 0.04. 5.3% of beams contained an MLC error greater than 1 mm and 2.4% had an error greater than 2mm. The mean gantry speed for VMAT plans was 1.01 degrees/s with a maximum of 6.5 degrees/s. Conclusion: Varian Dynalog files are useful for monitoring machine performance treatment parameters. The Dynalog files have shown that the performance of the Novalis Tx is consistent over the course of a patients treatment with only slight variations in patient treatment times and a low rate of MLC errors.

  17. Use of an amorphous silicon EPID for measuring MLC calibration at varying gantry angle

    International Nuclear Information System (INIS)

    Clarke, M F; Budgell, G J

    2008-01-01

    Amorphous silicon electronic portal imaging devices (EPIDs) are used to perform routine quality control (QC) checks on the multileaf collimators (MLCs) at this centre. Presently, these checks are performed at gantry angle 0 0 and are considered to be valid for all other angles. Since therapeutic procedures regularly require the delivery of MLC-defined fields to the patient at a wide range of gantry angles, the accuracy of the QC checks at other gantry angles has been investigated. When the gantry is rotated to angles other than 0 0 it was found that the apparent pixel size measured using the EPID varies up to a maximum value of 0.0015 mm per pixel due to a sag in the EPID of up to 9.2 mm. A correction factor was determined using two independent methods at a range of gantry angles between 0 deg. and 360 deg. The EPID was used to measure field sizes (defined by both x-jaws and MLC) at a range of gantry angles and, after this correction had been applied, any residual gravitational sag was studied. It was found that, when fields are defined by the x-jaws and y-back-up jaws, no errors of greater than 0.5 mm were measured and that these errors were no worse when the MLC was used. It was therefore concluded that, provided the correction is applied, measurements of the field size are, in practical terms, unaffected by gantry angle. Experiments were also performed to study how the reproducibility of individual leaves is affected by gantry angle. Measurements of the relative position of each individual leaf (minor offsets) were performed at a range of gantry angles and repeated three times. The position reproducibility was defined by the RMS error in the position of each leaf and this was found to be 0.24 mm and 0.21 mm for the two leaf banks at a gantry angle of 0 0 . When measurements were performed at a range of gantry angles, these reproducibility values remained within 0.09 mm and 0.11 mm. It was therefore concluded that the calibration of the Elekta MLC is stable at

  18. Comparative Analysis of Different Measurement Techniques for MLC Characterization: Preliminary Results

    International Nuclear Information System (INIS)

    Larraga-Gutierrez, J. M.; Ballesteros-Zebadua, P.; Garcia-Garduno, O. A.; Martinez-Davalos, A.; Rodriguez-Villafuerte, M.; Moreno-Jimenez, S.; Celis, M. A.

    2008-01-01

    Radiation transmission, leakage and beam penumbra are essential dosimetric parameters related to the commissioning of a multileaf collimation system. This work shows a comparative analysis of commonly used film detectors: X-OMAT V2 and EDR2 radiographic films, and GafChromic EBT registered radiochromic film. The results show that X-OMAT over-estimates radiation leakage and 80-20% beam penumbra. However, according to the reference values reported by the manufacturer for these dosimetric parameters, all three films are adequate for MLC dosimetric characterization, but special care must be taken when X-OMAT V2 film is used due to its low energy photon dependence

  19. SU-G-JeP1-05: Clinical Impact of MLC Tracking for Lung SABR

    Energy Technology Data Exchange (ETDEWEB)

    Caillet, V; Colvill, E [Faculty of Medecine, The University of Sydney, Sydney, NSW (Australia); Royal North Shore Hospital, Sydney, NSW (Australia); Szymura, K; Stevens, M; Booth, J [Royal North Shore Hospital, Sydney, NSW (Australia); Keall, P [Faculty of Medecine, The University of Sydney, Sydney, NSW (Australia)

    2016-06-15

    Purpose: The objective of this study was to investigate the dosimetric benefits of multi-leaf collimator (MLC) tracking for lung SABR treatments in end-to-end clinically realistic planning and delivery scenarios. Methods: The clinical benefits of MLC tracking were assessed using previously delivered treatment plans and physical experiments. The 10 most recent single lesion lung SABR patients were re-planned following a 4D-GTV-based real-time adaptive protocol (PTV defined as the end-of-exhalation GTV plus 5.0 mm margins). The plans were delivered on a Trilogy Varian linac. Electromagnetic transponders (Calypso, Varian Medical Systems, USA) were embedded into a programmable moving phantom (HexaMotion platform) tracked with the Varian Calypso system. For each physical experiment, the MLC positions were collected and used as input for dose reconstruction. For both planned and physical experiments, the OAR dose metrics from the conventional and real-time adaptive SABR plans (Mean Lung Dose (MLD), V20 for lung, and near-maximum dose (D2%) for spine and heart) were statistically compared. The Wilcoxon test was used to compare plan and physical experiment dose metrics. Results: While maintaining target coverage, percentage reductions in dose metrics to the OARs were observed for both planned and physical experiments. Comparing the two plans showed MLD percentage reduction (MLDr) of 25.4% (absolute differences of 1.41 Gy) and 28.9% (1.29%) for the V20r. D2% percentage reduction for spine and heart were respectively 27.9% (0.3 Gy) and 20.2% (0.3 Gy). For the physical experiments, MLDr was 23.9% (1.3 Gy), and V20r 37.4% (1.6%). D2% reduction for spine and heart were respectively 27.3% (0.3 Gy) and 19.6% (0.3 Gy). For both plans and physical experiments, significant OAR dose differences (p<0.05) were found between the conventional SABR and real-time adaptive plans. Conclusion: Application of MLC tracking for lung SABR patients has the potential to reduce the dose to OARs

  20. Independent dosimetric calculation with inclusion of head scatter and MLC transmission for IMRT

    International Nuclear Information System (INIS)

    Yang, Y.; Xing, L.; Li, J.G.; Palta, J.; Chen, Y.; Luxton, Gary; Boyer, A.

    2003-01-01

    Independent verification of the MU settings and dose calculation of IMRT treatment plans is an important step in the IMRT quality assurance (QA) procedure. At present, the verification is mainly based on experimental measurements, which are time consuming and labor intensive. Although a few simplified algorithms have recently been proposed for the independent dose (or MU) calculation, head scatter has not been precisely taken into account in all these investigations and the dose validation has mainly been limited to the central axis. In this work we developed an effective computer algorithm for IMRT MU and dose validation. The technique is superior to the currently available computer-based MU check systems in that (1) it takes full consideration of the head scatter and leaf transmission effects; and (2) it allows a precise dose calculation at an arbitrary spatial point instead of merely a point on the central axis. In the algorithm the dose at an arbitrary spatial point is expressed as a summation of the contributions of primary and scatter radiation from all beamlets. Each beamlet is modulated by a dynamic modulation factor (DMF), which is determined by the MLC leaf trajectories, the head scatter, the jaw positions, and the MLC leaf transmission. A three-source model was used to calculate the head scatter distribution for irregular segments shaped by MLC and the scatter dose contributions were computed using a modified Clarkson method. The system reads in MLC leaf sequence files (or RTP files) generated by the Corvus (NOMOS Corporation, Sewickley, PA) inverse planning system and then computes the doses at the desired points. The algorithm was applied to study the dose distributions of several testing intensity modulated fields and two multifield Corvus plans and the results were compared with Corvus plans and experimental measurements. The final dose calculations at most spatial points agreed with the experimental measurements to within 3% for both the specially

  1. Characterization of megavoltage electron beams delivered through a photon multi-leaf collimator (pMLC)

    Energy Technology Data Exchange (ETDEWEB)

    Plessis, F C P du; Leal, A; Stathakis, S; Xiong, W; Ma, C-M [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111 (United States)

    2006-04-21

    A study is presented that characterizes megavoltage electron beams delivered through an existing double-focused photon multi-leaf collimator (pMLC) using film measurements in a solid water phantom. Machine output stability and linearity were evaluated as well as the effect of source-to-surface distance (SSD) and field size on the penumbra for electron energies between 6 and 18 MeV over an SSD range of 60-100 cm. Penumbra variations as a function of field size, depth of measurement and the influence of the jaws were also studied. Field abutment, field flatness and target coverage for segmented beams were also addressed. The measured field size for electrons transported through the pMLC was the same as that for an x-ray beam up to SSDs of 70 cm. At larger SSD, the lower energy electron fields deviated from the projected field. Penumbra data indicated that 60 cm SSD was the most favourable treatment distance. Backprojection of P{sub 20-80} penumbra data yielded a virtual source position located at 98.9 cm from the surface for 18 MeV electrons. For 6 MeV electrons, the virtual source position was at a distance of 82.6 cm. Penumbra values were smaller for small beam slits and reached a near-constant value for field widths larger than 5 cm. The influence of the jaws had a small effect on the penumbra. The R{sub 90} values ranged from 1.4 to 4.8 cm between 6 and 21 MeV as measured at 60 cm SSD for a 9 x 9 cm{sup 2} field. Uniformity and penumbra improvement could be demonstrated using weighted abutted fields especially useful for small segments. No detectable electron leakage through the pMLC was observed. Bremsstrahlung measurements taken at 60 cm SSD for a 9 x 9 cm{sup 2} field as shaped by the pMLC compared within 1% to bremsstrahlung measurements taken at 100 cm SSD for a 10 x 10 cm{sup 2} electron applicator field at 100 cm SSD.

  2. SU-F-T-469: A Clinically Observed Discrepancy Between Image-Based and Log- Based MLC Position

    Energy Technology Data Exchange (ETDEWEB)

    Neal, B; Ahmed, M; Siebers, J [University of Virginia Health System, Charlottesville, VA (United States)

    2016-06-15

    Purpose: To present a clinical case which challenges the base assumption of log-file based QA, by showing that the actual position of a MLC leaf can suddenly deviate from its programmed and logged position by >1 mm as observed with real-time imaging. Methods: An EPID-based exit-fluence dosimetry system designed to prevent gross delivery errors was used in cine mode to capture portal images during treatment. Visual monitoring identified an anomalous MLC leaf pair gap not otherwise detected by the automatic position verification. The position of the erred leaf was measured on EPID images and log files were analyzed for the treatment in question, the prior day’s treatment, and for daily MLC test patterns acquired on those treatment days. Additional standard test patterns were used to quantify the leaf position. Results: Whereas the log file reported no difference between planned and recorded positions, image-based measurements showed the leaf to be 1.3±0.1 mm medial from the planned position. This offset was confirmed with the test pattern irradiations. Conclusion: It has been clinically observed that log-file derived leaf positions can differ from their actual positions by >1 mm, and therefore cannot be considered to be the actual leaf positions. This cautions the use of log-based methods for MLC or patient quality assurance without independent confirmation of log integrity. Frequent verification of MLC positions through independent means is a necessary precondition to trusting log file records. Intra-treatment EPID imaging provides a method to capture departures from MLC planned positions. Work was supported in part by Varian Medical Systems.

  3. Technical Note: A novel leaf sequencing optimization algorithm which considers previous underdose and overdose events for MLC tracking radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Wisotzky, Eric, E-mail: eric.wisotzky@charite.de, E-mail: eric.wisotzky@ipk.fraunhofer.de; O’Brien, Ricky; Keall, Paul J., E-mail: paul.keall@sydney.edu.au [Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Sydney, NSW 2006 (Australia)

    2016-01-15

    Purpose: Multileaf collimator (MLC) tracking radiotherapy is complex as the beam pattern needs to be modified due to the planned intensity modulation as well as the real-time target motion. The target motion cannot be planned; therefore, the modified beam pattern differs from the original plan and the MLC sequence needs to be recomputed online. Current MLC tracking algorithms use a greedy heuristic in that they optimize for a given time, but ignore past errors. To overcome this problem, the authors have developed and improved an algorithm that minimizes large underdose and overdose regions. Additionally, previous underdose and overdose events are taken into account to avoid regions with high quantity of dose events. Methods: The authors improved the existing MLC motion control algorithm by introducing a cumulative underdose/overdose map. This map represents the actual projection of the planned tumor shape and logs occurring dose events at each specific regions. These events have an impact on the dose cost calculation and reduce recurrence of dose events at each region. The authors studied the improvement of the new temporal optimization algorithm in terms of the L1-norm minimization of the sum of overdose and underdose compared to not accounting for previous dose events. For evaluation, the authors simulated the delivery of 5 conformal and 14 intensity-modulated radiotherapy (IMRT)-plans with 7 3D patient measured tumor motion traces. Results: Simulations with conformal shapes showed an improvement of L1-norm up to 8.5% after 100 MLC modification steps. Experiments showed comparable improvements with the same type of treatment plans. Conclusions: A novel leaf sequencing optimization algorithm which considers previous dose events for MLC tracking radiotherapy has been developed and investigated. Reductions in underdose/overdose are observed for conformal and IMRT delivery.

  4. The MLC tongue-and-groove effect on IMRT dose distributions

    Energy Technology Data Exchange (ETDEWEB)

    Deng Jun [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305 (United States). E-mail: jun@reyes.stanford.edu; Pawlicki, Todd; Chen Yan; Li Jinsheng; Jiang, Steve B.; Ma, C.-M. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305 (United States)

    2001-04-01

    We have investigated the tongue-and-groove effect on the IMRT dose distributions for a Varian MLC. We have compared the dose distributions calculated using the intensity maps with and without the tongue-and-groove effect. Our results showed that, for one intensity-modulated treatment field, the maximum tongue-and-groove effect could be up to 10% of the maximum dose in the dose distributions. For an IMRT treatment with multiple gantry angles ({>=} 5), the difference between the dose distributions with and without the tongue-and-groove effect was hardly visible, less than 1.6% for the two typical clinical cases studied. After considering the patient setup errors, the dose distributions were smoothed with reduced and insignificant differences between plans with and without the tongue-and-groove effect. Therefore, for a multiple-field IMRT plan ({>=} 5), the tongue-and-groove effect on the IMRT dose distributions will be generally clinically insignificant due to the smearing effect of individual fields. The tongue-and-groove effect on an IMRT plan with small number of fields (<5) will vary depending on the number of fields in a plan (coplanar or non-coplanar), the MLC leaf sequences and the patient setup uncertainty, and may be significant (>5% of maximum dose) in some cases, especially when the patient setup uncertainty is small ({<=} 2 mm). (author)

  5. The dosimetric impact of inversely optimized arc radiotherapy plan modulation for real-time dynamic MLC tracking delivery

    DEFF Research Database (Denmark)

    Falk, Marianne; Larsson, Tobias; Keall, P.

    2012-01-01

    Purpose: Real-time dynamic multileaf collimator (MLC) tracking for management of intrafraction tumor motion can be challenging for highly modulated beams, as the leaves need to travel far to adjust for target motion perpendicular to the leaf travel direction. The plan modulation can be reduced......-to-peak displacement of 2 cm and a cycle time of 6 s. The delivery was adjusted to the target motion using MLC tracking, guided in real-time by an infrared optical system. The dosimetric results were evaluated using gamma index evaluation with static target measurements as reference. Results: The plan quality...

  6. Effect of MLC leaf position, collimator rotation angle, and gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Sen; Li, Guangjun; Wang, Maojie; Jiang, Qinfeng; Zhang, Yingjie [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China); Wei, Yuquan, E-mail: yuquawei@vip.sina.com [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan (China)

    2013-07-01

    The purpose of this study was to investigate the effect of multileaf collimator (MLC) leaf position, collimator rotation angle, and accelerator gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma. To compare dosimetric differences between the simulating plans and the clinical plans with evaluation parameters, 6 patients with nasopharyngeal carcinoma were selected for simulation of systematic and random MLC leaf position errors, collimator rotation angle errors, and accelerator gantry rotation angle errors. There was a high sensitivity to dose distribution for systematic MLC leaf position errors in response to field size. When the systematic MLC position errors were 0.5, 1, and 2 mm, respectively, the maximum values of the mean dose deviation, observed in parotid glands, were 4.63%, 8.69%, and 18.32%, respectively. The dosimetric effect was comparatively small for systematic MLC shift errors. For random MLC errors up to 2 mm and collimator and gantry rotation angle errors up to 0.5°, the dosimetric effect was negligible. We suggest that quality control be regularly conducted for MLC leaves, so as to ensure that systematic MLC leaf position errors are within 0.5 mm. Because the dosimetric effect of 0.5° collimator and gantry rotation angle errors is negligible, it can be concluded that setting a proper threshold for allowed errors of collimator and gantry rotation angle may increase treatment efficacy and reduce treatment time.

  7. Genotoxic, radioprotective and radiosensitizing effect of curcumin and trans-resveratrol in vitro cultures of human lymphocytes; Efecto genotóxico, radioprotector y radiosensibilizante de la curcumina y el trans-resveratrol en cultivos in vitro de linfocitos humanos

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, V.A.; Tirsa Muñoz, B.; Sebastià, N.; Gómez-Cabrero, L.; La Parra, V.; Hervás, D.; Rodrigo, R.; Villaescusa, J.I.; Soriano, J.M.; Montoro, A.

    2015-07-01

    Curcumin and trans-resveratrol are natural polyphenol compounds. Curcumin is obtained from the rhizomes of the Curcumin plant (Curcuma longa), while trans-resveratrol is found in grapes, blackberries and other types of berry. These compounds have antioxidant, anti-inflammatory, immunostimulant and anticarcinogenic properties among others. In addition, they are also known for their radiomodulating properties since they are capable of providing radioprotection or radiosensitization for normal or tumours cells depending on different factors. This dual action may be the result of their properties, such as free radicals scavenging, as well as their influence on cell cycle checkpoints or control mechanisms. These are activated in response to the genetic damage induced by radiation. Despite the many beneficial properties attributed to these polyphenol compounds, some studies suggest that they are able to be genotoxic agents for some cellular lines. The results obtained indicate that both compounds possess a radioprotective effect on the lymphocytes of peripheral blood in the quiescent phase of the cellular cycle (G0). Nevertheless, they are capable of induce radiosensitivity on these type of cells in the growth phase (G2), and in addition, a different genotoxic effect can be seen according to the concentration of each compound. This study suggests, therefore, that curcumin and trans-resveratrol are able to exert a triple effect, genotoxic, radioprotective and radiosensitizing on in vitro cultures of human lymphocytes depending on the study parameters. [Spanish] La curcumina y el trans-resveratrol son compuestos polifenólicos de origen natural. La curcumina es obtenida a partir de los rizomas de la planta de la cúrcuma (Curcuma longa), mientras que el trans-resveratrol se encuentra en uvas, moras y otras bayas. Estos compuestos presentan propiedades antioxidantes, antiinflamatorias, inmunoestimulantes y anticancerígenas, entre otras. Además, también se les conoce por

  8. A new approach to the autoradiographic study of proliferating lymphocytes

    International Nuclear Information System (INIS)

    Zweiman, B.; Lisak, R.P.

    1978-01-01

    An adaptation of a cell filtration method for the autoradiographic study of cultured lymphocytes has been developed. The percentages of labelled cells are very similar in the filtered cell population to those obtained from replicate cultures processed by centrifugation. The filter method permitted a higher recovery of cells from small numbers in culture with better cytological detail than seen when cells were washed by repeated centrifugation, then suspended and smeared. (author)

  9. Cytogenetic analysis of the combined action of pesticides and radiation on human lymphocytes

    International Nuclear Information System (INIS)

    Ryabchenko, N.I.; Fesenko, Eh.V.; Antoshchina, M.M.

    1995-01-01

    The efficiency of the combined action of pesticides and irradiation at the G 0 stage was studied in cultured human lymphocytes. Carbophos (malathion) increased the yield of chromosome and chromatid fragments in irradiated lymphocytes. Herbicide 2,4-D (dichlorophenoxyacetic acid) raised lymphocyte radiosensitivity by increasing the yield of chromosome type aberrations, the radiosensitizing effect of the herbicide decreased as its concentration increased. 4 refs

  10. SU-E-T-479: IMRT Plan Recalculation in Patient Based On Dynalog Data and the Effect of a Single Failing MLC Motor

    Energy Technology Data Exchange (ETDEWEB)

    Morcos, M [Vantage Oncology, San Bernardino, CA (United States); Mitrou, E [Centre Hospitalier de l’Universite de Montreal, Montreal, QC (Canada)

    2015-06-15

    Purpose: Using Linac dynamic logs (Dynalogs) we evaluate the impact of a single failing MLC motor on the deliverability of an IMRT plan by assessing the recalculated dose volume histograms (DVHs) taking the delivered MLC positions and beam hold-offs into consideration. Methods: This is a retrospective study based on a deteriorating MLC motor (leaf 36B) which was observed to be failing via Dynalog analysis. To investigate further, Eclipse-importable MLC files were generated from Dynalogs to recalculate the actual delivered dose and to assess the clinical impact through DVHs. All deliveries were performed on a Varian 21EX linear accelerator equipped with Millennium-120 MLC. The analysis of Dynalog files and subsequent conversion to Eclipse-importable MLC files were all performed by in-house programming in Python. Effects on plan DVH are presented in the following section on a particular brain-IMRT plan which was delivered with a failing MLC motor which was then replaced. Results: Global max dose increased by 13.5%, max dose to the brainstem PRV increased by 8.2%, max dose to the optic chiasm increased by 7.6%, max dose to optic nerve increased by 8.8% and the mean dose to the PTV increased by 7.9% when comparing the original plan to the fraction with the failing MLC motor. The reason the dose increased was due to the failure being on the B-bank which is the lagging side on a sliding window delivery, therefore any failures on this side will cause an over-irradiation as the B-bank leaves struggles to keep the window from growing. Conclusion: Our findings suggest that a single failing MLC motor may jeopardize the entire delivery. This may be due to the bad MLC motor drawing too much current causing all MLCs on the same bank to underperform. This hypothesis will be investigated in a future study.

  11. SU-E-T-479: IMRT Plan Recalculation in Patient Based On Dynalog Data and the Effect of a Single Failing MLC Motor

    International Nuclear Information System (INIS)

    Morcos, M; Mitrou, E

    2015-01-01

    Purpose: Using Linac dynamic logs (Dynalogs) we evaluate the impact of a single failing MLC motor on the deliverability of an IMRT plan by assessing the recalculated dose volume histograms (DVHs) taking the delivered MLC positions and beam hold-offs into consideration. Methods: This is a retrospective study based on a deteriorating MLC motor (leaf 36B) which was observed to be failing via Dynalog analysis. To investigate further, Eclipse-importable MLC files were generated from Dynalogs to recalculate the actual delivered dose and to assess the clinical impact through DVHs. All deliveries were performed on a Varian 21EX linear accelerator equipped with Millennium-120 MLC. The analysis of Dynalog files and subsequent conversion to Eclipse-importable MLC files were all performed by in-house programming in Python. Effects on plan DVH are presented in the following section on a particular brain-IMRT plan which was delivered with a failing MLC motor which was then replaced. Results: Global max dose increased by 13.5%, max dose to the brainstem PRV increased by 8.2%, max dose to the optic chiasm increased by 7.6%, max dose to optic nerve increased by 8.8% and the mean dose to the PTV increased by 7.9% when comparing the original plan to the fraction with the failing MLC motor. The reason the dose increased was due to the failure being on the B-bank which is the lagging side on a sliding window delivery, therefore any failures on this side will cause an over-irradiation as the B-bank leaves struggles to keep the window from growing. Conclusion: Our findings suggest that a single failing MLC motor may jeopardize the entire delivery. This may be due to the bad MLC motor drawing too much current causing all MLCs on the same bank to underperform. This hypothesis will be investigated in a future study

  12. Curcumin and Cholecalciferol in Treating Patients With Previously Untreated Stage 0-II Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma

    Science.gov (United States)

    2018-01-26

    Contiguous Stage II Small Lymphocytic Lymphoma; Noncontiguous Stage II Small Lymphocytic Lymphoma; Stage 0 Chronic Lymphocytic Leukemia; Stage I Chronic Lymphocytic Leukemia; Stage I Small Lymphocytic Lymphoma; Stage II Chronic Lymphocytic Leukemia

  13. Clinically practical intensity modulation for complex head and neck lesions using multiple, static MLC fields

    International Nuclear Information System (INIS)

    Verhey, L.J.; Xia, P.; Akazawa, P.

    1997-01-01

    Purpose: A number of different beam delivery methods have been proposed for implementing intensity modulated radiotherapy (IMRT), including fixed gantry with multiple static MLC fields (MSMLC - often referred to as 'stop and shoot'), fixed gantry with dynamic MLC (DMLC), intensity modulated arc therapy (IMAT), Tomotherapy and Peacock MIMiC. Using two complex head and neck cases as examples, we have compared dose distributions achievable with 3-D conformal radiotherapy (3DCRT) to those which can be achieved using IMRT delivered with MSMLC, DMLC and Peacock MIMiC. The goal is to demonstrate the potential value of IMRT in the treatment of complex lesions in the head and neck and to determine whether MSMLC, the simplest of the proposed IMRT methods, can produce dose distributions which are competitive with dynamic IMRT methods and which can be implemented in clinically acceptable times. Materials and Methods: Two patients with nasopharyngeal carcinoma were selected from the archives of the Department of Radiation Oncology at the University of California, San Francisco (UCSF). These patients were previously planned and treated with CT-based 3-D treatment planning methods which are routinely used at UCSF, including non-axial beam directions and partial transmission blocks when indicated. The CT data tapes were then read into a test version of CORVUS, an inverse treatment planning program being developed by NOMOS Corporation, target volumes and critical normal structures were outlined on axial CT slices and dose goals and limits were defined for the targets and normal tissues of interest. Optimized dose plans were then obtained for each delivery method including MSMLC (4 or 5 hand-selected beams with 3 levels of intensity), DMLC (9 evenly spaced axial beams with 10 levels of intensity) and Peacock MIMiC (55 axial beams spanning 270 degrees with 10 levels of intensity). Dose-volume histograms (DVH's) for all IMRT plans were then compared with the 3DCRT plans. Treatment

  14. TH-AB-202-04: Auto-Adaptive Margin Generation for MLC-Tracked Radiotherapy

    International Nuclear Information System (INIS)

    Glitzner, M; Lagendijk, J; Raaymakers, B; Crijns, S; Fast, M; Nill, S; Oelfke, U; Denis de Senneville, B

    2016-01-01

    Purpose: To develop an auto-adaptive margin generator for MLC tracking. The generator is able to estimate errors arising in image guided radiotherapy, particularly on an MR-Linac, which depend on the latencies of machine and image processing, as well as on patient motion characteristics. From the estimated error distribution, a segment margin is generated, able to compensate errors up to a user-defined confidence. Method: In every tracking control cycle (TCC, 40ms), the desired aperture D(t) is compared to the actual aperture A(t), a delayed and imperfect representation of D(t). Thus an error e(t)=A(T)-D(T) is measured every TCC. Applying kernel-density-estimation (KDE), the cumulative distribution (CDF) of e(t) is estimated. With CDF-confidence limits, upper and lower error limits are extracted for motion axes along and perpendicular leaf-travel direction and applied as margins. To test the dosimetric impact, two representative motion traces were extracted from fast liver-MRI (10Hz). The traces were applied onto a 4D-motion platform and continuously tracked by an Elekta Agility 160 MLC using an artificially imposed tracking delay. Gafchromic film was used to detect dose exposition for static, tracked, and error-compensated tracking cases. The margin generator was parameterized to cover 90% of all tracking errors. Dosimetric impact was rated by calculating the ratio between underexposed points (>5% underdosage) to the total number of points inside FWHM of static exposure. Results: Without imposing adaptive margins, tracking experiments showed a ratio of underexposed points of 17.5% and 14.3% for two motion cases with imaging delays of 200ms and 300ms, respectively. Activating the margin generated yielded total suppression (<1%) of underdosed points. Conclusion: We showed that auto-adaptive error compensation using machine error statistics is possible for MLC tracking. The error compensation margins are calculated on-line, without the need of assuming motion or

  15. TH-AB-202-04: Auto-Adaptive Margin Generation for MLC-Tracked Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Glitzner, M; Lagendijk, J; Raaymakers, B; Crijns, S [University Medical Center Utrecht, Utrecht (Netherlands); Fast, M; Nill, S; Oelfke, U [The Institute of Cancer Research, London (United Kingdom); Denis de Senneville, B [University Medical Center Utrecht, Utrecht (Netherlands); IMB, UMR 5251 CNRS/University of Bordeaux, Talence, FR (France)

    2016-06-15

    Purpose: To develop an auto-adaptive margin generator for MLC tracking. The generator is able to estimate errors arising in image guided radiotherapy, particularly on an MR-Linac, which depend on the latencies of machine and image processing, as well as on patient motion characteristics. From the estimated error distribution, a segment margin is generated, able to compensate errors up to a user-defined confidence. Method: In every tracking control cycle (TCC, 40ms), the desired aperture D(t) is compared to the actual aperture A(t), a delayed and imperfect representation of D(t). Thus an error e(t)=A(T)-D(T) is measured every TCC. Applying kernel-density-estimation (KDE), the cumulative distribution (CDF) of e(t) is estimated. With CDF-confidence limits, upper and lower error limits are extracted for motion axes along and perpendicular leaf-travel direction and applied as margins. To test the dosimetric impact, two representative motion traces were extracted from fast liver-MRI (10Hz). The traces were applied onto a 4D-motion platform and continuously tracked by an Elekta Agility 160 MLC using an artificially imposed tracking delay. Gafchromic film was used to detect dose exposition for static, tracked, and error-compensated tracking cases. The margin generator was parameterized to cover 90% of all tracking errors. Dosimetric impact was rated by calculating the ratio between underexposed points (>5% underdosage) to the total number of points inside FWHM of static exposure. Results: Without imposing adaptive margins, tracking experiments showed a ratio of underexposed points of 17.5% and 14.3% for two motion cases with imaging delays of 200ms and 300ms, respectively. Activating the margin generated yielded total suppression (<1%) of underdosed points. Conclusion: We showed that auto-adaptive error compensation using machine error statistics is possible for MLC tracking. The error compensation margins are calculated on-line, without the need of assuming motion or

  16. SU-F-T-574: MLC Based SRS Beam Commissioning - Minimum Target Size Investigation

    Energy Technology Data Exchange (ETDEWEB)

    Zakikhani, R [Florida Cancer Specialists - Largo, Largo, FL (United States); Able, C [Florida Cancer Specialists - New Port Richey, New Port Richey, FL (United States)

    2016-06-15

    Purpose: To implement a MLC accelerator based SRS program using small fields down to 1 cm × 1 cm and to determine the smallest target size safe for clinical treatment. Methods: Computerized beam scanning was performed in water using a diode detector and a linac-head attached transmission ion chamber to characterize the small field dosimetric aspects of a 6 MV photon beam (Trilogy-Varian Medical Systems, Inc.). The output factors, PDD and profiles of field sizes 1, 2, 3, 4, and 10 cm{sup 2} were measured and utilized to create a new treatment planning system (TPS) model (AAA ver 11021). Static MLC SRS treatment plans were created and delivered to a homogeneous phantom (Cube 20, CIRS, Inc.) for a 1.0 cm and 1.5 cm “PTV” target. A 12 field DMLC plan was created for a 2.1 cm target. Radiochromic film (EBT3, Ashland Inc.) was used to measure the planar dose in the axial, coronal and sagittal planes. A micro ion chamber (0.007 cc) was used to measure the dose at isocenter for each treatment delivery. Results: The new TPS model was validated by using a tolerance criteria of 2% dose and 2 mm distance to agreement. For fields ≤ 3 cm{sup 2}, the max PDD, Profile and OF difference was 0.9%, 2%/2mm and 1.4% respectively. The measured radiochromic film planar dose distributions had gamma scores of 95.3% or higher using a 3%/2mm criteria. Ion chamber measurements for all 3 test plans effectively met our goal of delivering the dose accurately to within 5% when compared to the expected dose reported by the TPS (1 cm plan Δ= −5.2%, 1.5 cm plan Δ= −2.0%, 2 cm plan Δ= 1.5%). Conclusion: End to end testing confirmed that MLC defined SRS for target sizes ≥ 1.0 cm can be safely planned and delivered.

  17. Reconstruction of high resolution MLC leaf positions using a low resolution detector for accurate 3D dose reconstruction in IMRT

    NARCIS (Netherlands)

    Visser, R; Godart, J; Wauben, D J L; Langendijk, J A; Van't Veld, A A; Korevaar, E W

    2016-01-01

    In pre-treatment dose verification, low resolution detector systems are unable to identify shifts of individual leafs of high resolution multi leaf collimator (MLC) systems from detected changes in the dose deposition. The goal of this study was to introduce an alternative approach (the shutter

  18. Impact of MLC leaf position errors on simple and complex IMRT plans for head and neck cancer

    International Nuclear Information System (INIS)

    Mu, G; Ludlum, E; Xia, P

    2008-01-01

    The dosimetric impact of random and systematic multi-leaf collimator (MLC) leaf position errors is relatively unknown for head and neck intensity-modulated radiotherapy (IMRT) patients. In this report we studied 17 head and neck IMRT patients, including 12 treated with simple plans ( 100 segments). Random errors (-2 to +2 mm) and systematic errors (±0.5 mm and ±1 mm) in MLC leaf positions were introduced into the clinical plans and the resultant dose distributions were analyzed based on defined endpoint doses. The dosimetric effect was insignificant for random MLC leaf position errors up to 2 mm for both simple and complex plans. However, for systematic MLC leaf position errors, we found significant dosimetric differences between the simple and complex IMRT plans. For 1 mm systematic error, the average changes in D 95% were 4% in simple plans versus 8% in complex plans. The average changes in D 0.1cc of the spinal cord and brain stem were 4% in simple plans versus 12% in complex plans. The average changes in parotid glands were 9% in simple plans versus 13% for the complex plans. Overall, simple IMRT plans are less sensitive to leaf position errors than complex IMRT plans

  19. Radiosensitivities of sensitized lymphocytes

    International Nuclear Information System (INIS)

    Taniguchi, Kazuto

    1979-01-01

    Immunization of mice with cell antigens such as allogeneic tumor cells or xenogeneic erythrocytes raises a variety of immune reactions mediated by T lymphocytes: i.e. delayed type hypersensitivity (DTH), cytotoxicity, and antibody production. The radiosensitivities of these reactions were examined in mice exposed to 600 R x-irradiation a few hours before or after immunization. 1) DTH to xenogeneic erythrocytes, as demonstrated by footpad reaction, was not suppressed by irradiation 3 h before or after immunization. DTH to allogeneic tumor cells, as demonstrated by a migration inhibition test, hardly developed in mice that had been irradiated before or after immunization. It may have belonged to distinct types of delayed reactions which were mediated by distinct subpopulations of T lymphocytes. 2) Cytotoxicity against allogeneic cells and xenogeneic erythrocytes showed almost the same radiosensitivity. It was scarcely detected in mice that had been irradiated before immunization. However, a low but definite degree of cytotoxicity was detected in mice that had been irradiated only a few hours after immunization. Solubilized allogeneic cells instead of native cells were used as immunizing antigens. It was also possible for precursor cells with cytotoxicity to acquire a radioresistant nature by immunization of solubilized antigens, but native cells were required as stimulation for radioresistant precursor cells to differentiated into nature cytotoxic effector cells. 3) Antibody production against xenogeneic erythrocytes or allogeneic cells was almost completely depleted in mice that had been irradiated before or after immunization. It is possible that antibody production essentially requires cell division and clonal expansion of B lymphocytes. (Bell, E.)

  20. Fate of lymphocytes after withdrawal of tofacitinib treatment.

    Science.gov (United States)

    Piscianz, Elisa; Valencic, Erica; Cuzzoni, Eva; De Iudicibus, Sara; De Lorenzo, Elisa; Decorti, Giuliana; Tommasini, Alberto

    2014-01-01

    Tofacitinib (Tofa) is an inhibitor of Janus Kinase 3, developed for the treatment of autoimmune diseases and for the prevention of transplant rejection. Due to its selective action on proliferating cells, Tofa can offer a way to block T cell activation, without toxic effects on resting cells. However, few studies have investigated the effects of Tofa on lymphocyte activation in vitro. Our aim was to study the action of Tofa on different lymphocyte subsets after in vitro stimulation and to track the behaviour of treated cells after interruption of the treatment. Peripheral blood lymphocytes were stimulated in vitro with mitogen and treated with two concentrations of Tofa. After a first period in culture, cells were washed and further incubated for an additional time. Lymphocyte subsets, activation phenotype and proliferation were assessed at the different time frames. As expected, Tofa was able to reduce the activation and proliferation of lymphocytes in the first four days of treatment. In addition the drug led to a relative decrease of Natural Killer, B cells and CD8 T cells compared to CD4 T cells. However, treated cells were still viable after the first period in culture and begun to proliferate, strikingly, in a dose dependent manner when the drug was removed from the environment by replacing the culture medium. This novel data does not necessarily predict a similar behaviour in vivo, but can warn about the clinical use of this drug when a discontinuation of treatment with Tofa is considered for any reason.

  1. Fate of lymphocytes after withdrawal of tofacitinib treatment.

    Directory of Open Access Journals (Sweden)

    Elisa Piscianz

    Full Text Available Tofacitinib (Tofa is an inhibitor of Janus Kinase 3, developed for the treatment of autoimmune diseases and for the prevention of transplant rejection. Due to its selective action on proliferating cells, Tofa can offer a way to block T cell activation, without toxic effects on resting cells. However, few studies have investigated the effects of Tofa on lymphocyte activation in vitro. Our aim was to study the action of Tofa on different lymphocyte subsets after in vitro stimulation and to track the behaviour of treated cells after interruption of the treatment. Peripheral blood lymphocytes were stimulated in vitro with mitogen and treated with two concentrations of Tofa. After a first period in culture, cells were washed and further incubated for an additional time. Lymphocyte subsets, activation phenotype and proliferation were assessed at the different time frames. As expected, Tofa was able to reduce the activation and proliferation of lymphocytes in the first four days of treatment. In addition the drug led to a relative decrease of Natural Killer, B cells and CD8 T cells compared to CD4 T cells. However, treated cells were still viable after the first period in culture and begun to proliferate, strikingly, in a dose dependent manner when the drug was removed from the environment by replacing the culture medium. This novel data does not necessarily predict a similar behaviour in vivo, but can warn about the clinical use of this drug when a discontinuation of treatment with Tofa is considered for any reason.

  2. SU-G-JeP2-03: Automatic Quantification of MLC Positional Accuracy in An MRI Guided Radiotherapy System

    International Nuclear Information System (INIS)

    Li, X; Studenski, M; Yang, F; Dogan, N; Lamichhane, N; Padgett, K

    2016-01-01

    Purpose: MRI-guided-radiotherapy (MRIGRT) systems lack many features of traditional Linac based RT systems and specialized tests need to be developed to evaluate MLC performance. This work describes automatic tools for the analysis of positional accuracy of an MLC equipped MRIGRT system. Methods: This MLC analysis tool was developed for the MRIdian™ RT system which has three Co-60 equipped treatment heads each with a double focused MLC containing 30 leaf pairs, leaf thickness is 1.05cm defined at isocenter (SAD 105 cm). For MLC positional analysis a picket fence test was performed using a 25.4cm × 25.4cm Gafchromic™ RTQA2 film placed between 5cm solidwater and a 30cm × 30cm × 1cm jigwire phantom with seven embedded parallel metal strips 4cm apart. A plan was generated to deliver 2Gy per field and seven 23.1cm × 2cm fields centered over each wire in the phantom. For each leaf pair the center of the radiation profile was determined by fitting the horizontal profile with a Gaussian model and determining the center of the FWHM. This was compared with the metal strip location to determine any deviation. The following metrics were used to evaluate the deviations per gantry angle including maximum, minimum, mean, Kurtosis, and skewness. Results: The identified maximum/mean leaf deviations are, 1.32/0.55 mm for gantry 0°, 1.59/0.76 mm for gantry 90°, and 1.19/0.39 mm for gantry 270°. The percentage of leaf deviation less than 1mm are 90.0% at 0°, 74.6% at 90°, and 97.0% at 270°. Kurtosis/skewness of the leaf deviation are 2.41/0.14 at 0°, 2.53/0.23 at 90°, 3.33/0.83 at 270°, respectively. Conclusion: This work presents an automatic tool for evaluation of the MLC position accuracy of the MRIdian™ radiotherapy system which can be used to benchmark the performance of the MLC system for each treatment head and track the results longitudinally.

  3. In vitro X-ray irradiation of human peripheral blood T lymphocytes enhances suppressor function

    International Nuclear Information System (INIS)

    Ogawa, H.; Tsunematsu, T.

    1983-01-01

    The effect of in vitro X-ray irradiation on human peripheral blood T lymphocytes was studied with regard to their suppressor activity related to the concanavalin A (Con A)-induced suppressor system. To generate suppressor T lymphocytes, purified human T lymphocytes were incubated for 3 days in the first culture, with or without Con A. These lymphocytes were irradiated with various doses of X-ray before, mid or after the culture. After doing a second culture for 6 days, the suppressive influence of these cells on T lymphocyte proliferation rates stimulated with allogeneic mononuclear cells, and B lymphocyte proliferation rates stimulated with pokeweed mitogen was measured. Irradiation of cultures to which Con A had not been added induced much the same level of suppressor activity as seen in the cultures with Con A. The suppressor activity gradually increased with time from the irradiation to the suppressor cell assay. Suppressor T lymphocytes were resistant to X-ray irradiation and independent of DNA synthesis. However, irradiation-induced enhancement was minimal in cultures incubated with con A, regardless of the irradiation time. (author)

  4. Dosimetric evaluation of photon dose calculation under jaw and MLC shielding

    International Nuclear Information System (INIS)

    Fogliata, A.; Clivio, A.; Vanetti, E.; Nicolini, G.; Belosi, M. F.; Cozzi, L.

    2013-01-01

    Purpose: The accuracy of photon dose calculation algorithms in out-of-field regions is often neglected, despite its importance for organs at risk and peripheral dose evaluation. The present work has assessed this for the anisotropic analytical algorithm (AAA) and the Acuros-XB algorithms implemented in the Eclipse treatment planning system. Specifically, the regions shielded by the jaw, or the MLC, or both MLC and jaw for flattened and unflattened beams have been studied.Methods: The accuracy in out-of-field dose under different conditions was studied for two different algorithms. Measured depth doses out of the field, for different field sizes and various distances from the beam edge were compared with the corresponding AAA and Acuros-XB calculations in water. Four volumetric modulated arc therapy plans (in the RapidArc form) were optimized in a water equivalent phantom, PTW Octavius, to obtain a region always shielded by the MLC (or MLC and jaw) during the delivery. Doses to different points located in the shielded region and in a target-like structure were measured with an ion chamber, and results were compared with the AAA and Acuros-XB calculations. Photon beams of 6 and 10 MV, flattened and unflattened were used for the tests.Results: Good agreement between calculated and measured depth doses was found using both algorithms for all points measured at depth greater than 3 cm. The mean dose differences (±1SD) were −8%± 16%, −3%± 15%, −16%± 18%, and −9%± 16% for measurements vs AAA calculations and −10%± 14%, −5%± 12%, −19%± 17%, and −13%± 14% for Acuros-XB, for 6X, 6 flattening-filter free (FFF), 10X, and 10FFF beams, respectively. The same figures for dose differences relative to the open beam central axis dose were: −0.1%± 0.3%, 0.0%± 0.4%, −0.3%± 0.3%, and −0.1%± 0.3% for AAA and −0.2%± 0.4%, −0.1%± 0.4%, −0.5%± 0.5%, and −0.3%± 0.4% for Acuros-XB. Buildup dose was overestimated with AAA, while Acuros-XB gave

  5. SU-E-T-114: Analysis of MLC Errors On Gamma Pass Rates for Patient-Specific and Conventional Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Sterling, D; Ehler, E [University of Minnesota, Minneapolis, MN (United States)

    2015-06-15

    Purpose: To evaluate whether a 3D patient-specific phantom is better able to detect known MLC errors in a clinically delivered treatment plan than conventional phantoms. 3D printing may make fabrication of such phantoms feasible. Methods: Two types of MLC errors were introduced into a clinically delivered, non-coplanar IMRT, partial brain treatment plan. First, uniformly distributed random errors of up to 3mm, 2mm, and 1mm were introduced into the MLC positions for each field. Second, systematic MLC-bank position errors of 5mm, 3.5mm, and 2mm due to simulated effects of gantry and MLC sag were introduced. The original plan was recalculated with these errors on the original CT dataset as well as cylindrical and planar IMRT QA phantoms. The original dataset was considered to be a perfect 3D patient-specific phantom. The phantoms were considered to be ideal 3D dosimetry systems with no resolution limitations. Results: Passing rates for Gamma Index (3%/3mm and no dose threshold) were calculated on the 3D phantom, cylindrical phantom, and both on a composite and field-by-field basis for the planar phantom. Pass rates for 5mm systematic and 3mm random error were 86.0%, 89.6%, 98% and 98.3% respectively. For 3.5mm systematic and 2mm random error the pass rates were 94.7%, 96.2%, 99.2% and 99.2% respectively. For 2mm systematic error with 1mm random error the pass rates were 99.9%, 100%, 100% and 100% respectively. Conclusion: A 3D phantom with the patient anatomy is able to discern errors, both severe and subtle, that are not seen using conventional phantoms. Therefore, 3D phantoms may be beneficial for commissioning new treatment machines and modalities, patient-specific QA and end-to-end testing.

  6. High-Dose Spatially Fractionated GRID Radiation Therapy (SFGRT): A Comparison of Treatment Outcomes With Cerrobend vs. MLC SFGRT

    International Nuclear Information System (INIS)

    Neuner, Geoffrey; Mohiuddin, Majid M.; Vander Walde, Noam; Goloubeva, Olga; Ha, Jonathan; Yu, Cedric X.; Regine, William F.

    2012-01-01

    Purpose: Spatially fractionated GRID radiotherapy (SFGRT) using a customized Cerrobend block has been used to improve response rates in patients with bulky tumors. The clinical efficacy of our own multileaf collimator (MLC) technique is unknown. We undertook a retrospective analysis to compare clinical response rates attained using these two techniques. Methods and Materials: Seventy-nine patients with bulky tumors (median diameter, 7.6 cm; range, 4–30 cm) treated with SFGRT were reviewed. Between 2003 and late 2005, the Cerrobend block technique (n = 39) was used. Between late 2005 and 2008, SFGRT was delivered using MLC-shaped fields (n = 40). Dose was prescribed to dmax (depth of maximum dose) and was typically 15 Gy. Eighty percent of patients in both groups received external beam radiotherapy in addition to SFGRT. The two-sided Fisher-Freeman-Halton test was used to compare pain and mass effect response rates between the two groups. Results: Sixty-one patients (77%) were treated for palliative intent and 18 (23%) for curative intent. The majority of patients had either lung or head-and-neck primaries in both groups; the most frequent site of SFGRT application was the neck. The majority of patients complained of either pain (65%) or mass effect (58%) at intake. Overall response rates for pain and mass response were no different between the Cerrobend and MLC groups: pain, 75% and 74%, respectively (p = 0.50), and mass effect, 67% and 73%, respectively (p = 0.85). The majority of toxicities were Grade 1 or 2, and only 3 patients had late Grade 3-4 toxicities. Conclusions: MLC-based and Cerrobend-based SFGRT have comparable and encouraging response rates when used either in the palliative or curative setting. MLC-based SGFRT should allow clinics to more easily adopt this novel treatment approach for the treatment of bulky tumors.

  7. SU-E-T-312: Dosimetric Consideration for the Agility MLC When Planning Rotational SRT/SBRT Treatments

    Energy Technology Data Exchange (ETDEWEB)

    Kong, X; Harris, J; Spitznagel, D; Walker, J [Avera Medical Group - Radiation Oncology, Sioux Falls, SD (United States)

    2015-06-15

    Purpose: To analyze the radiation transmission of the Agility MLC and make recommendation based on the MLC dosimetric characteristics for SRT, SBRT and VMAT planning Method and Materials: Agility MLC is the newest model from Elekta and has no back up diaphragm behind leaves for this generation. Leaves are single focused with rounded end; composed of leafs each 0.5cm wide, 9cm thick, constructed from tungsten alloy and provide low transmission <0.5%. Total radiation transmission from leaves and diaphragm is <0.13%. A 360degree arc was generated using iCom tools; leaves were programmed closed while keeping the diaphragm fully open to maximize the MLC transmission effect. Gafchromic EBT films were sandwiched between 4cm of solid water and situated at midplane to take dose measurement. 5000MU was delivered using 6MV VersaHD, various collimator angles, and a 5cm central axis offset was tested also. Films were scanned with Epson 10000XL scanner and analyzed using DoseLab Pro. Results: Due to the rounded leaf end and nature of rotation therapy, dose accumulation through the leaf gap is significant. By offsetting the leaf gap from central axis, this accumulation can be greatly reduced. There are dark bands showing accumulation of interleaf transmission which is improved by increasing collimator angle from 0 to 45dgree. However for 45 degree, in most cases, there are larger volumes sweeping under MLC alone, which needs considered planning. Conclusions: While inter-leaf leakage is minimized by using collimator angles greater than 0 degrees, the location of the leaf gap must also be managed. The leaf gap position becomes critically important when the treatment area is off axis such is the case when more than one PTV is being treated. With VMAT for SRT, SBRT becoming a more popular planning technique, special attention needs to be paid when initially setting up the field geometry.

  8. SU-F-T-303: Quantification of MLC Positioning Accuracy in VMAT Delivery of Head and Neck Cancer Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Li, X; Yang, F [University Of Miami, Miami, FL (United States)

    2016-06-15

    Purpose: Knowing MLC leaf positioning error over the course of treatment would be valuable for treatment planning, QA design, and patient safety. The objective of the current study was to quantify the MLC positioning accuracy for VMAT delivery of head and neck treatment plans. Methods: A total of 837 MLC log files were collected from 14 head and neck cancer patients undergoing full arc VMAT treatment on one Varian Trilogy machine. The actual and planned leaf gaps were extracted from the retrieved MLC log files. For a given patient, the leaf gap error percentage (LGEP), defined as the ratio of the actual leaf gap over the planned, was evaluated for each leaf pair at all the gantry angles recorded over the course of the treatment. Statistics describing the distribution of the largest LGEP (LLGEP) of the 60 leaf pairs including the maximum, minimum, mean, Kurtosis, and skewness were evaluated. Results: For the 14 studied patients, their PTV located at tonsil, base of tongue, larynx, supraglottis, nasal cavity, and thyroid gland with volume ranging from 72.0 cm{sup 3} to 602.0 cm{sup 3}. The identified LLGEP differed between patients. It ranged from 183.9% to 457.7% with a mean of 368.6%. For the majority of the patients, the LLGEP distributions peaked at non-zero positions and showed no obvious dependence on gantry rotations. Kurtosis and skewness, with minimum/maximum of 66.6/217.9 and 6.5/12.6, respectively, suggested relatively more peaked while right-skewed leaf error distribution pattern. Conclusion: The results indicate pattern of MLC leaf gap error differs between patients of lesion located at similar anatomic site. Understanding the systemic mechanisms underlying these observed error patterns necessitates examining more patient-specific plan parameters in a large patient cohort setting.

  9. SU-E-T-114: Analysis of MLC Errors On Gamma Pass Rates for Patient-Specific and Conventional Phantoms

    International Nuclear Information System (INIS)

    Sterling, D; Ehler, E

    2015-01-01

    Purpose: To evaluate whether a 3D patient-specific phantom is better able to detect known MLC errors in a clinically delivered treatment plan than conventional phantoms. 3D printing may make fabrication of such phantoms feasible. Methods: Two types of MLC errors were introduced into a clinically delivered, non-coplanar IMRT, partial brain treatment plan. First, uniformly distributed random errors of up to 3mm, 2mm, and 1mm were introduced into the MLC positions for each field. Second, systematic MLC-bank position errors of 5mm, 3.5mm, and 2mm due to simulated effects of gantry and MLC sag were introduced. The original plan was recalculated with these errors on the original CT dataset as well as cylindrical and planar IMRT QA phantoms. The original dataset was considered to be a perfect 3D patient-specific phantom. The phantoms were considered to be ideal 3D dosimetry systems with no resolution limitations. Results: Passing rates for Gamma Index (3%/3mm and no dose threshold) were calculated on the 3D phantom, cylindrical phantom, and both on a composite and field-by-field basis for the planar phantom. Pass rates for 5mm systematic and 3mm random error were 86.0%, 89.6%, 98% and 98.3% respectively. For 3.5mm systematic and 2mm random error the pass rates were 94.7%, 96.2%, 99.2% and 99.2% respectively. For 2mm systematic error with 1mm random error the pass rates were 99.9%, 100%, 100% and 100% respectively. Conclusion: A 3D phantom with the patient anatomy is able to discern errors, both severe and subtle, that are not seen using conventional phantoms. Therefore, 3D phantoms may be beneficial for commissioning new treatment machines and modalities, patient-specific QA and end-to-end testing

  10. Independent Monte-Carlo dose calculation for MLC based CyberKnife radiotherapy

    Science.gov (United States)

    Mackeprang, P.-H.; Vuong, D.; Volken, W.; Henzen, D.; Schmidhalter, D.; Malthaner, M.; Mueller, S.; Frei, D.; Stampanoni, M. F. M.; Dal Pra, A.; Aebersold, D. M.; Fix, M. K.; Manser, P.

    2018-01-01

    This work aims to develop, implement and validate a Monte Carlo (MC)-based independent dose calculation (IDC) framework to perform patient-specific quality assurance (QA) for multi-leaf collimator (MLC)-based CyberKnife® (Accuray Inc., Sunnyvale, CA) treatment plans. The IDC framework uses an XML-format treatment plan as exported from the treatment planning system (TPS) and DICOM format patient CT data, an MC beam model using phase spaces, CyberKnife MLC beam modifier transport using the EGS++ class library, a beam sampling and coordinate transformation engine and dose scoring using DOSXYZnrc. The framework is validated against dose profiles and depth dose curves of single beams with varying field sizes in a water tank in units of cGy/Monitor Unit and against a 2D dose distribution of a full prostate treatment plan measured with Gafchromic EBT3 (Ashland Advanced Materials, Bridgewater, NJ) film in a homogeneous water-equivalent slab phantom. The film measurement is compared to IDC results by gamma analysis using 2% (global)/2 mm criteria. Further, the dose distribution of the clinical treatment plan in the patient CT is compared to TPS calculation by gamma analysis using the same criteria. Dose profiles from IDC calculation in a homogeneous water phantom agree within 2.3% of the global max dose or 1 mm distance to agreement to measurements for all except the smallest field size. Comparing the film measurement to calculated dose, 99.9% of all voxels pass gamma analysis, comparing dose calculated by the IDC framework to TPS calculated dose for the clinical prostate plan shows 99.0% passing rate. IDC calculated dose is found to be up to 5.6% lower than dose calculated by the TPS in this case near metal fiducial markers. An MC-based modular IDC framework was successfully developed, implemented and validated against measurements and is now available to perform patient-specific QA by IDC.

  11. Whole blood microculture assay of human lymphocyte function.

    Science.gov (United States)

    Pauly, J L; Han, T

    1976-11-01

    A whole blood microculture assay is described for measuring lymphocyte reactivity to mitogenic and antigenic stimulants. This assay employs heparinized whole blood, serum-free culture medium, microtiter plates, and a Multiple Automated Sample Harvester (MASH). When this assay is compared to other leukocyte assays, its major advantages include (1) the utilization of fewer lymphocytes per microculture, thuus reducing the amount of blood required per test while increasing the number of test agents and replicate cultures which can be employed in any given experiment; (2) the conservation of mitogens, antigens, drugs, enzymes, hormones, lymphokines, and other test agents, some of which are either expensive of difficult to prepare in large quantities; (3) the elimination of lymphocyte isolation and purification procedures which may disrupt the relative proportion of T cells, B cells and antigen-processing cells; and (4) the application of an automated harvester which simplifies and expedites procedures required for processing cells for liquid scintillation counting.

  12. Evidence for the replication of bovine leukemia virus in the B lymphocytes

    International Nuclear Information System (INIS)

    Paul, P.S.; Pomeroy, K.A.; Johnson, D.W.; Muscoplat, C.C.; Handwerger, B.S.; Soper, F.F.; Sorensen, D.K.

    1977-01-01

    Bovine peripheral blood lymphocytes from a cow with persistent lymphocytosis were separated on nylon wool columns into nylon-adherent and nonadherent populations. Nylon-adherent cells were highly enriched for surface immunoglobulin (SIg) bearing B lymphocytes (95.5%) and nonadherent cells for SIg negative non-B cells, presumably T lymphocytes (96.3%). The B lymphocytes were found to be the major producers for bovine leukemia virus. A total of 39% of the B-enriched cells, surviving after 72 hours in culture, produced bovine leukemia virus as compared with 0.5% of the non-B cells

  13. Food allergens inducing a lymphocyte-mediated immunological reaction in canine atopic-like dermatitis

    OpenAIRE

    SUTO, Akemi; SUTO, Yukinori; ONOHARA, Nozomi; TOMIZAWA, Yu; YAMAMOTO-SUGAWARA, Yukiko; OKAYAMA, Taro; MASUDA, Kenichi

    2014-01-01

    Canine atopic-like dermatitis (ALD) is suspected to be associated with food allergies, particularly those mediated by lymphocytes. In this study, 54 cases were included as ALD dogs, based on the negative IgE test results. In the dogs, the percentage of activated cells in helper-T lymphocytes was measured by flow cytometry using cultured peripheral lymphocytes under food allergen stimulation. We observed that 49 of the 54 ALD dogs (90.7%) had positive lymphocyte reactions against one or more f...

  14. REACTIVITY OF BLOOD LYMPHOCYTES IN PULMONARY TUBERCULOSIS

    Directory of Open Access Journals (Sweden)

    R. R. Khasanova

    2009-01-01

    Full Text Available Evaluation of proliferative and IL-2-producing activity of peripheral blood lymphocytes wasperformed, using cultural methods, in patients with drug-sensitive and drug-resistant infiltrative pulmonary tuberculosis. The cell testing was performed at basal level and following in vitro stimulation with recombinant IL-2 and M. tuberculosis antigens. It was established that clinical course of infiltrative pulmonary tuberculosis, independently on drug sensitivity/resistance of the infectious pathogen, is accompanied by suppression of spontaneous lymphoproliferation. The levels of induced IL-2 production in drug-sensitive tuberculosis proved to be increased, whereas a reserve of IL-2-secreting reactivity of blood lymphocytes was lower than in drugresistant infection. Also, it was revealed that the level of lymphoproliferative response induced by IL-2, does not depend on clinical variant of tuberculosis, whereas stimulation of IL-2 production in blood lymphocytes is attained only in cases of drug-resistant tuberculosis variant.

  15. Radiosensitivity of human lymphocytes and thymocytes

    International Nuclear Information System (INIS)

    Kwan, D.K.; Norman, A.

    1977-01-01

    The in vitro survival of human peripheral blood lymphocytes and thymocytes was measured 4 days following graded doses of γ radiation. Results indicate considerable heterogeneity among lymphocyte subpopulations with respect to radiosensitivity. Total T lymphocytes were characterized by rosette formation with neuraminidase-treated sheep red blood cells (nSRBC); early T (T/sub E/) cells, by early rosettes; and B cells, by their inability to form nSRBC rosettes. Late T (T/sub L/) cells were defined as T -- T/sub E/. Survival curves of T, T/sub E/, and B cells are biphasic. The radiosensitive and radioresistant components of T, T/sub E/, and B cells all have a D 0 of about 50 and 550 rad, respectively. B cells appeared to be slightly more radiosensitive than T cells. T/sub L/ cells and thymocytes, however, appeared to be homogeneous with respect to radiosensitivity, both having D 0 values of about 135 rad. The survival of T cells in mixed T and B cell cultures resembled that of separated T cells, suggesting that ionizing radiation has no significant effect on rosette formation. It also indicates that interactions of T and B cells do not significantly affect their radiation responses

  16. DNA repair in PHA stimulated human lymphocytes

    International Nuclear Information System (INIS)

    Catena, C.; Mattoni, A.

    1984-01-01

    Damage an repair of radiation induced DNA strand breaks were measured by alkaline lysis and hydroxyapatite chromatography. PHA stimulated human lymphocytes show that the rejoining process is complete within the first 50 min., afterwords secondary DNA damage and chromatid aberration. DNA repair, in synchronized culture, allows to evaluate individual repair capacity and this in turn can contribute to the discovery of individual who, although they do not demonstrate apparent clinical signs, are carriers of DNA repair deficiency. Being evident that a correlation exists between DNA repair capacity and carcinogenesis, the possibility of evaluating the existent relationship between DNA repair and survival in tumor cells comes therefore into discussion

  17. cultural

    Directory of Open Access Journals (Sweden)

    Irene Kreutz

    2006-01-01

    Full Text Available Es un estudio cualitativo que adoptó como referencial teorico-motodológico la antropología y la etnografía. Presenta las experiencias vivenciadas por mujeres de una comunidad en el proceso salud-enfermedad, con el objetivo de comprender los determinantes sócio-culturales e históricos de las prácticas de prevención y tratamiento adoptados por el grupo cultural por medio de la entrevista semi-estructurada. Los temas que emergieron fueron: la relación entre la alimentación y lo proceso salud-enfermedad, las relaciones con el sistema de salud oficial y el proceso salud-enfermedad y lo sobrenatural. Los dados revelaron que los moradores de la comunidad investigada tienen un modo particular de explicar sus procedimientos terapéuticos. Consideramos que es papel de los profesionales de la salud en sus prácticas, la adopción de abordajes o enfoques que consideren al individuo en su dimensión sócio-cultural e histórica, considerando la enorme diversidad cultural en nuestro país.

  18. Reactivity of eleven anti-human leucocyte monoclonal antibodies with lymphocytes from several domestic animals

    DEFF Research Database (Denmark)

    Aasted, Bent; Blixenkrone-Møller, Merete; Larsen, Else Bang

    1988-01-01

    Nine commercially available monoclonal antibodies and two monoclonal antibodies from The American Type Culture Collection, raised against various human leucocyte surface antigens, were tested on lymphocytes from cow, sheep, goat, swine, horse, cat, dog, mink, and rabbit as well as man. Four...... antibodies bound to lymphocytes from some of the animals. These were the antibodies against CD8 and CD4 antigen, the antibody to C3b-receptor, and the antibody to the HLA-DR antigen. The CD8 antigen-reactive antibody reacted with lymphocytes from mink, cat, dog, and sheep, while the CD4 antigen......-reactive antibody reacted with lymphocytes from mink. The anti-C3b-R antibody reacted with lymphocytes from horse, swine, dog, and cat, and the anti-HLA-DR reacted with lymphocytes from cow, goat, sheep, horse, dog, cat, and mink....

  19. Lymphocyte signaling: beyond knockouts.

    Science.gov (United States)

    Saveliev, Alexander; Tybulewicz, Victor L J

    2009-04-01

    The analysis of lymphocyte signaling was greatly enhanced by the advent of gene targeting, which allows the selective inactivation of a single gene. Although this gene 'knockout' approach is often informative, in many cases, the phenotype resulting from gene ablation might not provide a complete picture of the function of the corresponding protein. If a protein has multiple functions within a single or several signaling pathways, or stabilizes other proteins in a complex, the phenotypic consequences of a gene knockout may manifest as a combination of several different perturbations. In these cases, gene targeting to 'knock in' subtle point mutations might provide more accurate insight into protein function. However, to be informative, such mutations must be carefully based on structural and biophysical data.

  20. MRI of lymphocytic hypophysitis

    International Nuclear Information System (INIS)

    Feng Feng; Li Mingli; Li Xiaozhen; Meng Chunling; Jin zhengyu

    2005-01-01

    Objective: To describe the MR findings in patients with lymphocytic hypophysitis (LyH), and to discuss MR diagnostic value and limit in this disease entity and its differentiation with pituitary adenoma. Methods: Five pathologically proven cases of LyH were recruited in this study. The main complaints of the patients were polydipsia, polyuria, and headache. The preoperative MR images and clinical manifestations were analyzed retrospectively. Results: MR findings of the 5 patients with LyH included enlargement of pituitary gland, stalk thickening, disappearance of high signal of neurohypophysis on T 1 WI, and marked Gadolinium enhancement of the lesions. Homogeneous enhancement was found in 2 cases, while heterogeneous enhancement was in 3 cases. Involvement of the cavernous sinus and dura mater on dorsum sella and clivus were found in 2 patients. Conclusion: The diagnosis of LyH should be suggested when the enlarged pituitary gland is associated with central diabetes insipidus, and with/without dysfunction of adenohypophysis. (authors)

  1. Validation of Varian TrueBeam electron phase–spaces for Monte Carlo simulation of MLC-shaped fields

    International Nuclear Information System (INIS)

    Lloyd, Samantha A. M.; Gagne, Isabelle M.; Zavgorodni, Sergei; Bazalova-Carter, Magdalena

    2016-01-01

    Purpose: This work evaluates Varian’s electron phase–space sources for Monte Carlo simulation of the TrueBeam for modulated electron radiation therapy (MERT) and combined, modulated photon and electron radiation therapy (MPERT) where fields are shaped by the photon multileaf collimator (MLC) and delivered at 70 cm SSD. Methods: Monte Carlo simulations performed with EGSnrc-based BEAMnrc/DOSXYZnrc and PENELOPE-based PRIMO are compared against diode measurements for 5 × 5, 10 × 10, and 20 × 20 cm 2 MLC-shaped fields delivered with 6, 12, and 20 MeV electrons at 70 cm SSD (jaws set to 40 × 40 cm 2 ). Depth dose curves and profiles are examined. In addition, EGSnrc-based simulations of relative output as a function of MLC-field size and jaw-position are compared against ion chamber measurements for MLC-shaped fields between 3 × 3 and 25 × 25 cm 2 and jaw positions that range from the MLC-field size to 40 × 40 cm 2 . Results: Percent depth dose curves generated by BEAMnrc/DOSXYZnrc and PRIMO agree with measurement within 2%, 2 mm except for PRIMO’s 12 MeV, 20 × 20 cm 2 field where 90% of dose points agree within 2%, 2 mm. Without the distance to agreement, differences between measurement and simulation are as large as 7.3%. Characterization of simulated dose parameters such as FWHM, penumbra width and depths of 90%, 80%, 50%, and 20% dose agree within 2 mm of measurement for all fields except for the FWHM of the 6 MeV, 20 × 20 cm 2 field which falls within 2 mm distance to agreement. Differences between simulation and measurement exist in the profile shoulders and penumbra tails, in particular for 10 × 10 and 20 × 20 cm 2 fields of 20 MeV electrons, where both sets of simulated data fall short of measurement by as much as 3.5%. BEAMnrc/DOSXYZnrc simulated outputs agree with measurement within 2.3% except for 6 MeV MLC-shaped fields. Discrepancies here are as great as 5.5%. Conclusions: TrueBeam electron phase–spaces available from Varian have been

  2. Treatment planning for MLC based robotic radiosurgery for brain metastases: plan comparison with circular fields and suggestions for planning strategies

    Directory of Open Access Journals (Sweden)

    Schmitt Daniela

    2017-09-01

    Full Text Available To evaluate the possible range of application of the new InCise2 MLC for the CyberKnife M6 system in brain radiosurgery, a plan comparison was made for 10 brain metastases sized between 1.5 and 9cm3 in 10 patients treated in a single fraction each. The target volumes consist of a PTV derived by expanding the GTV by 1mm and were chosen to have diversity in the cohort regarding regularity of shape, location and the structures needed to be blocked for beam transmission in the vicinity. For each case, two treatment plans were optimized: one using the MLC and one using the IRIS-collimator providing variable circular fields. Plan re-quirements were: dose prescription to the 70% isodose line (18 or 20Gy, 100% GTV coverage, ≥98% PTV coverage, undisturbed central high dose region (95% of maximum dose and a conformity index as low as possible. Plan com-parison parameters were: conformity index (CI, high-dose gradient index (GIH, low-dose gradient index (GIL, total number of monitor units (MU and expected treatment time (TT. For all cases, clinically acceptable plans could be gen-erated with the following results (mean±SD for CI, GIH, GIL, MU and TT, respectively for the MLC plans: 1.09±0.03, 2.77±0.26, 2.61±0.08, 4514±830MU and 27±5min and for the IRIS plans: 1.05±0.01, 3.00±0.35, 2.46±0.08, 8557±1335MU and 42±7min. In summary, the MLC plans were on average less conformal and had a shallower dose gradient in the low dose region, but a steeper dose gradient in the high dose region. This is accompanied by a smaller vol-ume receiving 10Gy. A plan by plan comparison shows that usage of the MLC can spare about one half of the MUs and one third of treatment time. From these experiences and results suggestions for MLC planning strategy can be de-duced.

  3. Validation of Varian TrueBeam electron phase–spaces for Monte Carlo simulation of MLC-shaped fields

    Energy Technology Data Exchange (ETDEWEB)

    Lloyd, Samantha A. M. [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8P 3P6 5C2 (Canada); Gagne, Isabelle M., E-mail: imgagne@bccancer.bc.ca; Zavgorodni, Sergei [Department of Medical Physics, BC Cancer Agency–Vancouver Island Centre, Victoria, British Columbia V8R 6V5, Canada and Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 5C2 (Canada); Bazalova-Carter, Magdalena [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 5C2 (Canada)

    2016-06-15

    Purpose: This work evaluates Varian’s electron phase–space sources for Monte Carlo simulation of the TrueBeam for modulated electron radiation therapy (MERT) and combined, modulated photon and electron radiation therapy (MPERT) where fields are shaped by the photon multileaf collimator (MLC) and delivered at 70 cm SSD. Methods: Monte Carlo simulations performed with EGSnrc-based BEAMnrc/DOSXYZnrc and PENELOPE-based PRIMO are compared against diode measurements for 5 × 5, 10 × 10, and 20 × 20 cm{sup 2} MLC-shaped fields delivered with 6, 12, and 20 MeV electrons at 70 cm SSD (jaws set to 40 × 40 cm{sup 2}). Depth dose curves and profiles are examined. In addition, EGSnrc-based simulations of relative output as a function of MLC-field size and jaw-position are compared against ion chamber measurements for MLC-shaped fields between 3 × 3 and 25 × 25 cm{sup 2} and jaw positions that range from the MLC-field size to 40 × 40 cm{sup 2}. Results: Percent depth dose curves generated by BEAMnrc/DOSXYZnrc and PRIMO agree with measurement within 2%, 2 mm except for PRIMO’s 12 MeV, 20 × 20 cm{sup 2} field where 90% of dose points agree within 2%, 2 mm. Without the distance to agreement, differences between measurement and simulation are as large as 7.3%. Characterization of simulated dose parameters such as FWHM, penumbra width and depths of 90%, 80%, 50%, and 20% dose agree within 2 mm of measurement for all fields except for the FWHM of the 6 MeV, 20 × 20 cm{sup 2} field which falls within 2 mm distance to agreement. Differences between simulation and measurement exist in the profile shoulders and penumbra tails, in particular for 10 × 10 and 20 × 20 cm{sup 2} fields of 20 MeV electrons, where both sets of simulated data fall short of measurement by as much as 3.5%. BEAMnrc/DOSXYZnrc simulated outputs agree with measurement within 2.3% except for 6 MeV MLC-shaped fields. Discrepancies here are as great as 5.5%. Conclusions: TrueBeam electron phase

  4. AFFORDABLE MULTI-LAYER CERAMIC (MLC) MANUFACTURING FOR POWER SYSTEMS (AMPS)

    Energy Technology Data Exchange (ETDEWEB)

    E.A. Barringer, Ph.D.

    2002-11-27

    McDermott Technology, Inc. (MTI) is attempting to develop high-performance, cost-competitive solid oxide fuel cell (SOFC) power systems. Recognizing the challenges and limitations facing the development of SOFC stacks comprised of electrode-supported cells and metallic interconnects, McDermott Technology, Inc. (MTI) has chosen to pursue an alternate path to commercialization. MTI is developing a multi-layer, co-fired, planar SOFC stack that will provide superior performance and reliability at reduced costs relative to competing designs. The MTI approach combines state-of-the-art SOFC materials with the manufacturing technology and infrastructure established for multi-layer ceramic (MLC) packages for the microelectronics industry. The rationale for using MLC packaging technology is that high quality, low-cost manufacturing has been demonstrated at high volumes. With the proper selection of SOFC materials, implementation of MLC fabrication methods offers unique designs for stacks (cells and interconnects) that are not possible through traditional fabrication methods. The MTI approach eliminates use of metal interconnects and ceramic-metal seals, which are primary sources of stack performance degradation. Co-fired cells are less susceptible to thermal cycling stresses by using material compositions that have closely matched coefficients of thermal expansion between the cell and the interconnect. The development of this SOFC stack technology was initiated in October 1999 under the DOE cosponsored program entitled ''Affordable Multi-layer Ceramic Manufacturing for Power Systems (AMPS)''. The AMPS Program was conducted as a two-phase program: Phase I--Feasibility Assessment (10/99--9/00); and Phase II--Process Development for Co-fired Stacks (10/00-3/02). This report provides a summary of the results from Phase I and a more detailed review of the results for Phase II. Phase I demonstrated the feasibility for fabricating multi-layer, co-fired cells and

  5. Radiosensitivity of lymphocytes in vitro

    International Nuclear Information System (INIS)

    Albrecht, S.

    1979-01-01

    The radiation-induced impairment of human T-lymphocytes was studied after in vitro exposure to 25.8 - 825.6 mC/kg (100 - 3200 R) of 60 Co γ-radiation by ascertaining the change in lymphocyte response to phytohaemagglutin stimulation. Following methods were used: (1) measurement of 3 H-thymidine uptake, (2) E-rosette test, and (3) morphological examination of transformed T-cells. The results revealed a dose-dependent decline in T-cell number which was still somewhat more marked with lymphocytes purified over Ficoll-Isopaque prior to irradiation. (author)

  6. Laboratorial diagnosis of lymphocytic meningitis

    Directory of Open Access Journals (Sweden)

    Sérgio Monteiro de Almeida

    Full Text Available Meningitis is the main infectious central nervous system (CNS syndrome. Viruses or bacteria can cause acute meningitis of infectious etiology. The term "Aseptic Meningitis" denotes a clinical syndrome with a predominance of lymphocytes in the cerebrospinal fluid (CSF, with no common bacterial agents identified in the CSF. Viral meningitis is considered the main cause of lymphocyte meningitis. There are other etiologies of an infectious nature. CSF examination is essential to establish the diagnosis and to identify the etiological agent of lymphocytic meningitis. We examined CSF characteristics and the differential diagnosis of the main types of meningitis.

  7. SU-E-T-119: Dosimetric and Mechanical Characteristics of Elekta Infinity LINAC with Agility MLC

    International Nuclear Information System (INIS)

    Park, J; Xu, Q; Xue, J; Zhai, Y; An, L; Chen, Y

    2014-01-01

    Purpose: Elekta Infinity is the one of the latest generation LINAC with unique features. Two Infinity LINACs are recently commissioned at our institution. The dosimetric and mechanical characteristics of the machines are presented. Methods: Both Infinity LINACs with Agility MLC (160 leaves with 0.5 cm leaf width) are configured with five electron energies (6, 9, 12, 15, and 18 MeV) and two photon energies (6 and 15 MV). One machine has additional photon energy (10 MV). The commissioning was performed by following the manufacturer's specifications and AAPM TG recommendations. Beam data of both electron and photon beams are measured with scanning ion chambers and linear diode array. Machines are adjusted to have the dosimetrically equivalent characteristics. Results: The commissioning of mechanical and imaging system meets the tolerances by TG recommendations. The PDD 10 of various field sizes for 6 and 15 MV shows < 0.5% difference between two machines. For each electron beams, R 80 matches with < 0.4 mm difference. The symmetry and flatness agree within 0.8% and 0.9% differences for photon beams, respectively. For electron beams, the differences of the symmetry and flatness are within 1.2% and 0.8%, respectively. The mean inline penumbras for 6, 10, and 15 MV are respectively 5.1±0.24, 5.6±0.07, and 5.9±0.10 mm for 10x10 cm at 10 cm depth. The crossline penumbras are larger than inline penumbras by 2.2, 1.4, and 1.0 mm, respectively. The MLC transmission factor with interleaf leakage is 0.5 % for all photon energies. Conclusion: The dosimetric and mechanical characteristics of two Infinity LINACs show good agreements between them. Although the Elekta Infinity has been used in many institutions, the detailed characteristics of the machine have not been reported. This study provides invaluable information to understand the Infinity LINAC and to compare the quality of commissioning data for other LINACs

  8. SU-C-BRB-04: Characteristics and Performance Evaluation of the First Commercial MLC for a Robotic Delivery System

    Energy Technology Data Exchange (ETDEWEB)

    Fuerweger, C [Erasmus MC Cancer Institute, Rotterdam (Netherlands); European Cyberknife Center Munich, Munich, DE (Germany); Prins, P; Coskan, H; Heijmen, B [Erasmus MC Cancer Institute, Rotterdam (Netherlands)

    2015-06-15

    Purpose: To assess characteristics and performance of the “Incise™” MLC (41 leaf pairs, 2.5mm width, FFF linac) mounted on the robotic SRS/SBRT platform “CyberKnife M6™” in a pre-clinical 5 months (11/2014–03/2015) test period. Methods: Beam properties were measured with unshielded diodes and EBT3 film. The CyberKnife workspace for MLC was analyzed by transforming robot node coordinates (cranial / body paths) into Euler geometry. Bayouth tests for leaf / bank position accuracy were performed in standard (A/P) and clinically relevant non-standard positions, before and after exercising the MLC for 10+ minutes. Total system and delivery accuracy were assessed in End-to-End tests and dosimetric verification of exemplary plans. Stability over time was evaluated in Picket-Fence-and adapted Winston-Lutz-tests (AQA) for different collimator angles. Results: Penumbrae (80–20%, with 100%=2*dose at inflection point; SAD 80cm; 10cm depth) parallel / perpendicular to leaf motion were 2.87/2.64mm for the smallest (0×76×0.75cm{sup 2}) and 5.34/4.94mm for the largest (9.76×9.75cm{sup 2}) square field. MLC circular field penumbrae exceeded fixed cones by 10–20% (e.g. 60mm: 4.0 vs. 3.6mm; 20mm: 3.6 vs. 2.9mm). Interleaf leakage was <0.5%. Clinically accessible workspace with MLC covered (non-coplanar) gantry angles of [-113°;+112°] (cranial) and [-108°;+102°] (body), and collimator angles of [-100°;+107°] (cranial) and [-91°;+100°] (body). Average leaf position offsets were ≤0.2mm in 14 standard A/P Bayouth tests and ≤0.6mm in 8 non-standard direction tests. Pre-test MLC exercise increased jaggedness (range ±0.3mm vs. ±0.5mm) and allowed to identify one malfunctioning leaf motor. Total system accuracy with MLC was 0.39±0.06mm in 6 End-to-End tests. Picket-Fence and AQA showed no adverse trends during the test period. Conclusion: The Incise™ MLC for CyberKnife M6™ displayed high accuracy and mechanical stability over the test period. The

  9. Comparison of two Classification methods (MLC and SVM) to extract land use and land cover in Johor Malaysia

    Science.gov (United States)

    Rokni Deilmai, B.; Ahmad, B. Bin; Zabihi, H.

    2014-06-01

    Mapping is essential for the analysis of the land use and land cover, which influence many environmental processes and properties. For the purpose of the creation of land cover maps, it is important to minimize error. These errors will propagate into later analyses based on these land cover maps. The reliability of land cover maps derived from remotely sensed data depends on an accurate classification. In this study, we have analyzed multispectral data using two different classifiers including Maximum Likelihood Classifier (MLC) and Support Vector Machine (SVM). To pursue this aim, Landsat Thematic Mapper data and identical field-based training sample datasets in Johor Malaysia used for each classification method, which results indicate in five land cover classes forest, oil palm, urban area, water, rubber. Classification results indicate that SVM was more accurate than MLC. With demonstrated capability to produce reliable cover results, the SVM methods should be especially useful for land cover classification.

  10. SU-C-BRB-04: Characteristics and Performance Evaluation of the First Commercial MLC for a Robotic Delivery System

    International Nuclear Information System (INIS)

    Fuerweger, C; Prins, P; Coskan, H; Heijmen, B

    2015-01-01

    Purpose: To assess characteristics and performance of the “Incise™” MLC (41 leaf pairs, 2.5mm width, FFF linac) mounted on the robotic SRS/SBRT platform “CyberKnife M6™” in a pre-clinical 5 months (11/2014–03/2015) test period. Methods: Beam properties were measured with unshielded diodes and EBT3 film. The CyberKnife workspace for MLC was analyzed by transforming robot node coordinates (cranial / body paths) into Euler geometry. Bayouth tests for leaf / bank position accuracy were performed in standard (A/P) and clinically relevant non-standard positions, before and after exercising the MLC for 10+ minutes. Total system and delivery accuracy were assessed in End-to-End tests and dosimetric verification of exemplary plans. Stability over time was evaluated in Picket-Fence-and adapted Winston-Lutz-tests (AQA) for different collimator angles. Results: Penumbrae (80–20%, with 100%=2*dose at inflection point; SAD 80cm; 10cm depth) parallel / perpendicular to leaf motion were 2.87/2.64mm for the smallest (0×76×0.75cm 2 ) and 5.34/4.94mm for the largest (9.76×9.75cm 2 ) square field. MLC circular field penumbrae exceeded fixed cones by 10–20% (e.g. 60mm: 4.0 vs. 3.6mm; 20mm: 3.6 vs. 2.9mm). Interleaf leakage was <0.5%. Clinically accessible workspace with MLC covered (non-coplanar) gantry angles of [-113°;+112°] (cranial) and [-108°;+102°] (body), and collimator angles of [-100°;+107°] (cranial) and [-91°;+100°] (body). Average leaf position offsets were ≤0.2mm in 14 standard A/P Bayouth tests and ≤0.6mm in 8 non-standard direction tests. Pre-test MLC exercise increased jaggedness (range ±0.3mm vs. ±0.5mm) and allowed to identify one malfunctioning leaf motor. Total system accuracy with MLC was 0.39±0.06mm in 6 End-to-End tests. Picket-Fence and AQA showed no adverse trends during the test period. Conclusion: The Incise™ MLC for CyberKnife M6™ displayed high accuracy and mechanical stability over the test period. The specific Cyber

  11. Comparison of two Classification methods (MLC and SVM) to extract land use and land cover in Johor Malaysia

    International Nuclear Information System (INIS)

    Deilmai, B Rokni; Ahmad, B Bin; Zabihi, H

    2014-01-01

    Mapping is essential for the analysis of the land use and land cover, which influence many environmental processes and properties. For the purpose of the creation of land cover maps, it is important to minimize error. These errors will propagate into later analyses based on these land cover maps. The reliability of land cover maps derived from remotely sensed data depends on an accurate classification. In this study, we have analyzed multispectral data using two different classifiers including Maximum Likelihood Classifier (MLC) and Support Vector Machine (SVM). To pursue this aim, Landsat Thematic Mapper data and identical field-based training sample datasets in Johor Malaysia used for each classification method, which results indicate in five land cover classes forest, oil palm, urban area, water, rubber. Classification results indicate that SVM was more accurate than MLC. With demonstrated capability to produce reliable cover results, the SVM methods should be especially useful for land cover classification

  12. SU-F-T-366: Dosimetric Parameters Enhancement of 120-Leaf Millennium MLC Using EGSnrc and IAEA Phase-Space Data

    International Nuclear Information System (INIS)

    Haddad, K; Alopoor, H

    2016-01-01

    Purpose: Recently, the multileaf collimators (MLC) have become an important part of any LINAC collimation systems because they reduce the treatment planning time and improves the conformity. Important factors that affects the MLCs collimation performance are leaves material composition and their thickness. In this study, we investigate the main dosimetric parameters of 120-leaf Millennium MLC including dose in the buildup point, physical penumbra as well as average and end leaf leakages. Effects of the leaves geometry and density on these parameters are evaluated Methods: From EGSnrc Monte Carlo code, BEAMnrc and DOSXYZnrc modules are used to evaluate the dosimetric parameters of a water phantom exposed to a Varian xi for 100cm SSD. Using IAEA phasespace data just above MLC (Z=46cm) and BEAMnrc, for the modified 120-leaf Millennium MLC a new phase space data at Z=52cm is produces. The MLC is modified both in leaf thickness and material composition. EGSgui code generates 521ICRU library for tungsten alloys. DOSXYZnrc with the new phase space evaluates the dose distribution in a water phantom of 60×60×20 cm3 with voxel size of 4×4×2 mm3. Using DOSXYZnrc dose distributions for open beam and closed beam as well as the leakages definition, end leakage, average leakage and physical penumbra are evaluated. Results: A new MLC with improved dosimetric parameters is proposed. The physical penumbra for proposed MLC is 4.7mm compared to 5.16 mm for Millennium. Average leakage in our design is reduced to 1.16% compared to 1.73% for Millennium, the end leaf leakage suggested design is also reduced to 4.86% compared to 7.26% of Millennium. Conclusion: The results show that the proposed MLC with enhanced dosimetric parameters could improve the conformity of treatment planning.

  13. SU-F-T-429: Craniospinal Irradiation by VMAT Technique: Impact of FFF Beam and High Resolution MLC On Plan Quality

    Energy Technology Data Exchange (ETDEWEB)

    Ganesh, T; Sarkar, B; Munshi, A; Mohanti, B [Fortis Memorial Research Institute, Gurgaon, Haryana (India)

    2016-06-15

    Purpose: Objective of this study was to evaluate the impact of using flattening filter free (FFF) beam with 0.5 cm multileaf collimator (MLC) leaves over conventional flattened beam with 1 cm leaf width MLC on the treatment plan quality in cranio-spinal irradiation (CSI). Methods: For five medulloblastoma cases (3 males and 2 females), who were previously treated by volumetric modulated arc therapy (VMAT) technique using conventional flattened beam shaped by 1 cm width MLC leaves, four test plans were generated and compared against the delivered plan. These retrospective plans consisted of four different combinations of flattened and FFF beams from Elekta’s Agility treatment head with 0.5 cm width MLC leaves. Sparing of organs at risks (OAR) in terms of dose to 5%, 50%, 75% and 90% volumes, mean and maximum dose were evaluated. Results: All plans satisfied the planning objective of covering 95% of PTV by at least 95% of prescription dose. Marginal variation of dose spillage was observed between different VMAT plans at very low dose range (1–5 Gy). Variation in dose statistics for PTVs and OARs were within 1% or 1 Gy. Amongst the five plans, the plan with flattened beam with 1 cm MLC had the highest number of MUs, 2.13 times higher than the plan with Agility MLC with FFF beam that had the least number of MUs. No statistically significant difference (p≥0.05) was observed between the reference plan and the retrospectively generated plans in terms of PTV coverage, cold spot, hot spot and organ at risk doses. Conclusion: In the treatment of CSI cases by VMAT technique, FFF beams and/or finer width MLC did not exhibit advantage over the flattened beams or wider MLC in terms of plan quality except for reduction in MUs.

  14. SU-F-T-366: Dosimetric Parameters Enhancement of 120-Leaf Millennium MLC Using EGSnrc and IAEA Phase-Space Data

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, K; Alopoor, H [Shiraz University, Shiraz, I.R. Iran (Iran, Islamic Republic of)

    2016-06-15

    Purpose: Recently, the multileaf collimators (MLC) have become an important part of any LINAC collimation systems because they reduce the treatment planning time and improves the conformity. Important factors that affects the MLCs collimation performance are leaves material composition and their thickness. In this study, we investigate the main dosimetric parameters of 120-leaf Millennium MLC including dose in the buildup point, physical penumbra as well as average and end leaf leakages. Effects of the leaves geometry and density on these parameters are evaluated Methods: From EGSnrc Monte Carlo code, BEAMnrc and DOSXYZnrc modules are used to evaluate the dosimetric parameters of a water phantom exposed to a Varian xi for 100cm SSD. Using IAEA phasespace data just above MLC (Z=46cm) and BEAMnrc, for the modified 120-leaf Millennium MLC a new phase space data at Z=52cm is produces. The MLC is modified both in leaf thickness and material composition. EGSgui code generates 521ICRU library for tungsten alloys. DOSXYZnrc with the new phase space evaluates the dose distribution in a water phantom of 60×60×20 cm3 with voxel size of 4×4×2 mm3. Using DOSXYZnrc dose distributions for open beam and closed beam as well as the leakages definition, end leakage, average leakage and physical penumbra are evaluated. Results: A new MLC with improved dosimetric parameters is proposed. The physical penumbra for proposed MLC is 4.7mm compared to 5.16 mm for Millennium. Average leakage in our design is reduced to 1.16% compared to 1.73% for Millennium, the end leaf leakage suggested design is also reduced to 4.86% compared to 7.26% of Millennium. Conclusion: The results show that the proposed MLC with enhanced dosimetric parameters could improve the conformity of treatment planning.

  15. Technical Note: Motion-perturbation method applied to dosimetry of dynamic MLC target tracking—A proof-of-concept

    Energy Technology Data Exchange (ETDEWEB)

    Feygelman, Vladimir, E-mail: vladimir.feygelman@moffitt.org; Tonner, Brian; Hunt, Dylan; Zhang, Geoffrey; Moros, Eduardo [Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612 (United States); Stambaugh, Cassandra [Department of Physics, University of South Florida, Tampa, Florida 33612 (United States); Nelms, Benjamin E. [Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States)

    2015-11-15

    Purpose: Previous studies show that dose to a moving target can be estimated using 4D measurement-guided dose reconstruction based on a process called virtual motion simulation, or VMS. A potential extension of VMS is to estimate dose during dynamic multileaf collimator (MLC)-tracking treatments. The authors introduce a modified VMS method and quantify its performance as proof-of-concept for tracking applications. Methods: Direct measurements with a moving biplanar diode array were used to verify accuracy of the VMS dose estimates. A tracking environment for variably sized circular MLC apertures was simulated by sending preprogrammed control points to the MLC while simultaneously moving the accelerator treatment table. Sensitivity of the method to simulated tracking latency (0–700 ms) was also studied. Potential applicability of VMS to fast changing beam apertures was evaluated by modeling, based on the demonstrated dependence of the cumulative dose on the temporal dose gradient. Results: When physical and virtual latencies were matched, the agreement rates (2% global/2 mm gamma) between the VMS and the biplanar dosimeter were above 96%. When compared to their own reference dose (0 induced latency), the agreement rates for VMS and biplanar array track closely up to 200 ms of induced latency with 10% low-dose cutoff threshold and 300 ms with 50% cutoff. Time-resolved measurements suggest that even in the modulated beams, the error in the cumulative dose introduced by the 200 ms VMS time resolution is not likely to exceed 0.5%. Conclusions: Based on current results and prior benchmarks of VMS accuracy, the authors postulate that this approach should be applicable to any MLC-tracking treatments where leaf speeds do not exceed those of the current Varian accelerators.

  16. Immunosuppressant MPA Modulates Tight Junction through Epigenetic Activation of MLCK/MLC-2 Pathway via p38MAPK

    Directory of Open Access Journals (Sweden)

    Niamat Khan

    2015-12-01

    Full Text Available Background: Mycophenolic acid (MPA is an important immunosuppressive drug (ISD prescribed to prevent graft rejection in the organ transplanted patients, however, its use is also associated with adverse side effects like sporadic gastrointestinal (GI disturbances. Recently, we reported the MPA induced tight junctions (TJs deregulation which involves MLCK/MLC-2 pathway. Here, we investigated the global histone acetylation as well as gene-specific chromatin signature of several genes associated with TJs regulation in Caco-2 cells after MPA treatment.Results: The epigenetic analysis shows that MPA treatment increases the global histone acetylation levels as well as the enrichment for transcriptional active histone modification mark (H3K4me3 at promoter regions of p38MAPK, ATF-2, MLCK, and MLC-2. In contrast, the promoter region of occludin was enriched for transcriptional repressive histone modification mark (H3K27me3 after MPA treatment. In line with the chromatin status, MPA treatment increased the expression of p38MAPK, ATF-2, MLCK, and MLC-2 both at transcriptional and translational level, while occludin expression was negatively influenced. Interestingly, the MPA induced gene expression changes and functional properties of Caco-2 cells could be blocked by the inhibition of p38MAPK using a chemical inhibitor (SB203580.Conclusions: Collectively, our results highlight that MPA disrupts the structure of TJs via p38MAPK-dependent activation of MLCK/MLC-2 pathway that results in decreased integrity of Caco-2 monolayer. These results led us to suggest that p38MAPK-mediated lose integrity of epithelial monolayer could be the possible cause of GI disturbance (barrier dysfunction in the intestine, leading to leaky style diarrhea observed in the organ-transplanted patients treated with MPA.

  17. Technical Note: Motion-perturbation method applied to dosimetry of dynamic MLC target tracking—A proof-of-concept

    International Nuclear Information System (INIS)

    Feygelman, Vladimir; Tonner, Brian; Hunt, Dylan; Zhang, Geoffrey; Moros, Eduardo; Stambaugh, Cassandra; Nelms, Benjamin E.

    2015-01-01

    Purpose: Previous studies show that dose to a moving target can be estimated using 4D measurement-guided dose reconstruction based on a process called virtual motion simulation, or VMS. A potential extension of VMS is to estimate dose during dynamic multileaf collimator (MLC)-tracking treatments. The authors introduce a modified VMS method and quantify its performance as proof-of-concept for tracking applications. Methods: Direct measurements with a moving biplanar diode array were used to verify accuracy of the VMS dose estimates. A tracking environment for variably sized circular MLC apertures was simulated by sending preprogrammed control points to the MLC while simultaneously moving the accelerator treatment table. Sensitivity of the method to simulated tracking latency (0–700 ms) was also studied. Potential applicability of VMS to fast changing beam apertures was evaluated by modeling, based on the demonstrated dependence of the cumulative dose on the temporal dose gradient. Results: When physical and virtual latencies were matched, the agreement rates (2% global/2 mm gamma) between the VMS and the biplanar dosimeter were above 96%. When compared to their own reference dose (0 induced latency), the agreement rates for VMS and biplanar array track closely up to 200 ms of induced latency with 10% low-dose cutoff threshold and 300 ms with 50% cutoff. Time-resolved measurements suggest that even in the modulated beams, the error in the cumulative dose introduced by the 200 ms VMS time resolution is not likely to exceed 0.5%. Conclusions: Based on current results and prior benchmarks of VMS accuracy, the authors postulate that this approach should be applicable to any MLC-tracking treatments where leaf speeds do not exceed those of the current Varian accelerators

  18. Stages of Chronic Lymphocytic Leukemia

    Science.gov (United States)

    ... of the lymph system . Having relatives who are Russian Jews or Eastern European Jews. Signs and symptoms ... information about clinical trials is also available. To Learn More About Chronic Lymphocytic Leukemia For more information ...

  19. Safety and Efficacy of MLC601 in Iranian Patients after Stroke: A Double-Blind, Placebo-Controlled Clinical Trial

    Directory of Open Access Journals (Sweden)

    A. A. Harandi

    2011-01-01

    Full Text Available Objective. To investigate the safety and efficacy of MLC601 (NeuroAid as a traditional Chinese medicine on motor recovery after ischemic stroke. Methods. This study was a double-blind, placebo-controlled clinical trial on 150 patients with a recent (less than 1 month ischemic stroke. All patients were given either MLC601 (100 patients or placebo (50 patients, 4 capsules 3 times a day, as an add-on to standard stroke treatment for 3 months. Results. Sex, age, elapsed time from stroke onset, and risk factors in the treatment group were not significantly different from placebo group at baseline (P>.05. Repeated measures analysis showed that Fugl-Meyer assessment was significantly higher in the treatment group during 12 weeks after stroke (P<.001. Good tolerability to treatment was shown, and adverse events were mild and transient. Conclusion. MLC601 showed better motor recovery than placebo and was safe on top of standard ischemic stroke medications especially in the severe and moderate cases.

  20. Heterologous expression of MlcE in Saccharomyces cerevisiae provides resistance to natural and semi-synthetic statins

    Directory of Open Access Journals (Sweden)

    Ana Ley

    2015-12-01

    Full Text Available Statins are inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the key enzyme in cholesterol biosynthesis. Their extensive use in treatment and prevention of cardiovascular diseases placed statins among the best selling drugs. Construction of Saccharomyces cerevisiae cell factory for the production of high concentrations of natural statins will require establishment of a non-destructive self-resistance mechanism to overcome the undesirable growth inhibition effects of statins. To establish active export of statins from yeast, and thereby detoxification, we integrated a putative efflux pump-encoding gene mlcE from the mevastatin-producing Penicillium citrinum into the S. cerevisiae genome. The resulting strain showed increased resistance to both natural statins (mevastatin and lovastatin and semi-synthetic statin (simvastatin when compared to the wild type strain. Expression of RFP-tagged mlcE showed that MlcE is localized to the yeast plasma and vacuolar membranes. We provide a possible engineering strategy for improvement of future yeast based production of natural and semi-synthetic statins. Keywords: Polyketide, Statins, Saccharomyces cerevisiae, Transport, Cell factory, Resistance

  1. Lymphocyte colony forming units and its application to the study of radiosensitivity

    International Nuclear Information System (INIS)

    Ma Xiangrui; Wang Tao; Wang Hongyun

    1991-07-01

    Kinetics and radiosensitivity of human lymphocytes were studied by the techniques of monolayer agar culture and liquid culture in vitro. In the experiments of lymphocyte kinetics, PHA was designated as a motogen for T lymphocyte. LPS, MEBC and BSA were chosen as mitogens for B lymphocyte. The data from thses experiments showed that under the alone or combination stimulation of LPS, MRBC and BSA, B lymphocytes developed to form colonies in agar culture (0.3%) with the same manner. The stimulation of LPS to B lymphocytes was most significant. By the day 6 after seeding, the numbers of colonies in agar culture were maximal. Whereas the numbers decreased significantly by the day 8. The number of T lymphocyte colonies increased with culture time within 12 days. The peak of 3 H-TdR incorporation into T lymphocytes in liquid culture occured at 5th day after seeding. The data above-mentioned demonstrated that the kinetics of lymphocytes cultured in two kinds of environments were different. The studies of the radiosensitivity of T lymphocytes showed that the decreasing in the number of colonies and rate of 3 H-TdR incorporation varied in different dose ranges. In the range of 0∼1.0 Gy, r = -0.96, D 0 value was 1.71 Gy for TL-CFC in agar culture, r = -.96, D 0 value was 4.34 Gy for the proliferation T lymphocytes in liquid culture. In the range of 1.0∼6.0 Gy, r were -0.99 and -0.98, the D 0 were 5.88 and 7.36 Gy respectively. The declining tendency in colonies formed by BL-CFC was the same as that of TL-CFC, r = -0.97, for the range of 0∼1.0 Gy, r = -0.97, for the range of 1.0∼3.0, the D 0 values were 1.35 and 4.36 Gy respectively. The results from these experiments shown that the colony technique was a good method for the study in radiosensitivity

  2. Comparison of measured and calculated doses for narrow MLC defined fields

    International Nuclear Information System (INIS)

    Lydon, J.; Rozenfeld, A.; Lerch, M.

    2002-01-01

    Full text: The introduction of Intensity Modulated Radiotherapy (IMRT) has led to the use of narrow fields in the delivery of radiation doses to patients. Such fields are not well characterized by calculation methods commonly used in radiotherapy treatment planning systems. The accuracy of the dose calculation algorithm must therefore be investigated prior to clinical use. This study looked at symmetrical and asymmetrical 0.1 to 3cm wide fields delivered with a Varian CL2100C 6MV photon beam. Measured doses were compared to doses calculated using Pinnacle, the ADAC radiotherapy treatment planning system. Two high resolution methods of measuring dose were used. A MOSFET detector in a water phantom and radiographic film in a solid water phantom with spatial resolutions of 10 and 89μm respectively. Dose calculations were performed using the collapsed cone convolution algorithm in Pinnacle with a 0.1cm dose calculation grid in the MLC direction. The effect of Pinnacle not taking into account the rounded leaf ends was simulated by offsetting the leaves by 0.1cm in the dose calculation. Agreement between measurement and calculation is good for fields of 1cm and wider. However, fields of less than 1cm width can show a significant difference between measurement and calculation

  3. Effect on canine lymphocyte function of 144Ce inhaled in fused clay particles

    International Nuclear Information System (INIS)

    Benjamin, S.A.; Ferris, A.C.

    1974-01-01

    Beagle dogs exposed by inhalation to 144 Ce in fused clay particles develop a persistent lymphopenia and the remaining peripheral lymphocytes in these dogs show a depressed in vitro response to plant mitogens. These studies were designed to evaluate the cellular basis for this defect. The survival and growth of lymphocytes from irradiated and control dogs were evaluated through 96 hours of culture. Many irradiated lymphocytes that were viable in vivo died within 24 hours in vitro. The remaining lymphocytes appeared to grow normally indicating that the early in vitro death was responsible for at least a portion of the difference between irradiated and control lymphocyte cultures. A second experiment was designed to determine if any humoral factors in plasma of irradiated dogs were responsible for the poor response of the lymphocytes. Lymphocytes from irradiated and control dogs were grown with plasma from both types of animals. Heterologous plasma had no apparent effect on lymphocyte growth, indicating that humoral factors were not involved. (U.S.)

  4. Alteration of lymphocyte functions by 8-methoxypsoralen and longwave ultraviolet radiation. I. Suppressive effects of PUVA on T-lymphocyte migration in vitro

    International Nuclear Information System (INIS)

    Okamoto, H.; Takigawa, M.; Horio, T.

    1985-01-01

    We investigated the influence of 8-methoxypsoralen (8-MOP) plus long-wave ultraviolet radiation (PUVA) on lymphocyte migration in vitro. Nylon wool-purified, mouse splenic T lymphocytes showed locomotive responses to casein, normal mouse serum (NMS), and zymosan-activated mouse serum (ZAS). Migratory responses to casein and NMS, and to ZAS were remarkably suppressed in lymphocytes exposed to 0.5 J/cm2 UVA plus 0.1 micrograms/ml 8-MOP and to 0.8 J/cm2 UVA plus 8-MOP, respectively. The PUVA treatment used in the present study had no effect on random movement and lymphocyte viability. T lymphocytes cultured in the absence of mitogenic agent for 24 h demonstrated a greater increase in their migration activity than noncultured cells, while lymphocytes cultured after 1.0 J/cm2 PUVA pretreatment remained low. These findings suggest that the therapeutic effect of PUVA on inflammatory skin disorders may be due in part to the suppression of lymphocyte migration

  5. TH-AB-202-03: A Novel Tool for Computing Deliverable Doses in Dynamic MLC Tracking Treatments

    Energy Technology Data Exchange (ETDEWEB)

    Fast, M; Kamerling, C; Menten, M; Nill, S; Oelfke, U [The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London (United Kingdom); Crijns, S; Raaymakers, B [University Medical Center Utrecht, Utrecht (Netherlands)

    2016-06-15

    Purpose: In tracked dynamic multi-leaf collimator (MLC) treatments, segments are continuously adapted to the target centroid motion in beams-eye-view. On-the-fly segment adaptation, however, potentially induces dosimetric errors due to the finite MLC leaf width and non-rigid target motion. In this study, we outline a novel tool for computing the 4d dose of lung SBRT plans delivered with MLC tracking. Methods: The following automated workflow was developed: A) centroid tracking, where the initial segments are morphed to each 4dCT phase based on the beams-eye-view GTV shift (followed by a dose calculation on each phase); B) re-optimized tracking, in which all morphed initial plans from (A) are further optimised (“warm-started”) in each 4dCT phase using the initial optimisation parameters but phase-specific volume definitions. Finally, both dose sets are accumulated to the reference phase using deformable image registration. Initial plans were generated according to the RTOG-1021 guideline (54Gy, 3-Fx, equidistant 9-beam IMRT) on the peak-exhale (reference) phase of a phase-binned 4dCT. Treatment planning and delivery simulations were performed in RayStation (research v4.6) using our in-house segment-morphing algorithm, which directly links to RayStation through a native C++ interface. Results: Computing the tracking plans and 4d dose distributions via the in-house interface takes 5 and 8 minutes respectively for centroid and re-optimized tracking. For a sample lung SBRT patient with 14mm peak-to-peak motion in sup-inf direction, mainly perpendicular leaf motion (0-collimator) resulted in small dose changes for PTV-D95 (−13cGy) and GTV-D98 (+18cGy) for the centroid tracking case compared to the initial plan. Modest reductions of OAR doses (e.g. spinal cord D2: −11cGy) were achieved in the idealized tracking case. Conclusion: This study presents an automated “1-click” workflow for computing deliverable MLC tracking doses in RayStation. Adding a non

  6. Experimental investigation of a moving averaging algorithm for motion perpendicular to the leaf travel direction in dynamic MLC target tracking

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jai-Woong; Sawant, Amit; Suh, Yelin; Cho, Byung-Chul; Suh, Tae-Suk; Keall, Paul [Department of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul, Korea 131-700 and Research Institute of Biomedical Engineering, Catholic University of Korea, Seoul, 131-700 (Korea, Republic of); Department of Radiation Oncology, Stanford University, Stanford, California 94305 (United States); Department of Radiation Oncology, Stanford University, Stanford, California 94305 (United States) and Department of Radiation Oncology, Asan Medical Center, Seoul, 138-736 (Korea, Republic of); Department of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul, 131-700 and Research Institute of Biomedical Engineering, Catholic University of Korea, Seoul, 131-700 (Korea, Republic of); Department of Radiation Oncology, Stanford University, Stanford, California 94305 (United States) and Radiation Physics Laboratory, Sydney Medical School, University of Sydney, 2006 (Australia)

    2011-07-15

    Purpose: In dynamic multileaf collimator (MLC) motion tracking with complex intensity-modulated radiation therapy (IMRT) fields, target motion perpendicular to the MLC leaf travel direction can cause beam holds, which increase beam delivery time by up to a factor of 4. As a means to balance delivery efficiency and accuracy, a moving average algorithm was incorporated into a dynamic MLC motion tracking system (i.e., moving average tracking) to account for target motion perpendicular to the MLC leaf travel direction. The experimental investigation of the moving average algorithm compared with real-time tracking and no compensation beam delivery is described. Methods: The properties of the moving average algorithm were measured and compared with those of real-time tracking (dynamic MLC motion tracking accounting for both target motion parallel and perpendicular to the leaf travel direction) and no compensation beam delivery. The algorithm was investigated using a synthetic motion trace with a baseline drift and four patient-measured 3D tumor motion traces representing regular and irregular motions with varying baseline drifts. Each motion trace was reproduced by a moving platform. The delivery efficiency, geometric accuracy, and dosimetric accuracy were evaluated for conformal, step-and-shoot IMRT, and dynamic sliding window IMRT treatment plans using the synthetic and patient motion traces. The dosimetric accuracy was quantified via a {gamma}-test with a 3%/3 mm criterion. Results: The delivery efficiency ranged from 89 to 100% for moving average tracking, 26%-100% for real-time tracking, and 100% (by definition) for no compensation. The root-mean-square geometric error ranged from 3.2 to 4.0 mm for moving average tracking, 0.7-1.1 mm for real-time tracking, and 3.7-7.2 mm for no compensation. The percentage of dosimetric points failing the {gamma}-test ranged from 4 to 30% for moving average tracking, 0%-23% for real-time tracking, and 10%-47% for no compensation

  7. An MLC-based linac QA procedure for the characterization of radiation isocenter and room lasers' position

    International Nuclear Information System (INIS)

    Rosca, Florin; Lorenz, Friedlieb; Hacker, Fred L.; Chin, Lee M.; Ramakrishna, Naren; Zygmanski, Piotr

    2006-01-01

    We have designed and implemented a new stereotactic linac QA test with stereotactic precision. The test is used to characterize gantry sag, couch wobble, cone placement, MLC offsets, and room lasers' positions relative to the radiation isocenter. Two MLC star patterns, a cone pattern, and the laser line patterns are recorded on the same imaging medium. Phosphor plates are used as imaging medium due to their sensitivity to red light. The red light of room lasers erases some of the irradiation information stored on the phosphor plates enabling accurate and direct measurements for the position of room lasers and radiation isocenter. Using film instead of the phosphor plate as imaging medium is possible, however, it is less practical. The QA method consists of irradiating four phosphor plates that record the gantry sag between the 0 deg.and 180 deg.gantry angles, the position and stability of couch rotational axis, the sag between the 90 deg.and 270 deg.gantry angles, the accuracy of cone placement on the collimator, the MLC offsets from the collimator rotational axis, and the position of laser lines relative to the radiation isocenter. The estimated accuracy of the method is ±0.2 mm. The observed reproducibility of the method is about ±0.1 mm. The total irradiation/illumination time is about 10 min per image. Data analysis, including the phosphor plate scanning, takes less than 5 min for each image. The method characterizes the radiation isocenter geometry with the high accuracy required for the stereotactic radiosurgery. In this respect, it is similar to the standard ball test for stereotactic machines. However, due to the usage of the MLC instead of the cross-hair/ball, it does not depend on the cross-hair/ball placement errors with respect to the lasers and it provides more information on the mechanical integrity of the linac/couch/laser system. Alternatively, it can be used as a highly accurate QA procedure for the nonstereotactic machines. Noteworthy is its

  8. Experimental investigation of a moving averaging algorithm for motion perpendicular to the leaf travel direction in dynamic MLC target tracking.

    Science.gov (United States)

    Yoon, Jai-Woong; Sawant, Amit; Suh, Yelin; Cho, Byung-Chul; Suh, Tae-Suk; Keall, Paul

    2011-07-01

    In dynamic multileaf collimator (MLC) motion tracking with complex intensity-modulated radiation therapy (IMRT) fields, target motion perpendicular to the MLC leaf travel direction can cause beam holds, which increase beam delivery time by up to a factor of 4. As a means to balance delivery efficiency and accuracy, a moving average algorithm was incorporated into a dynamic MLC motion tracking system (i.e., moving average tracking) to account for target motion perpendicular to the MLC leaf travel direction. The experimental investigation of the moving average algorithm compared with real-time tracking and no compensation beam delivery is described. The properties of the moving average algorithm were measured and compared with those of real-time tracking (dynamic MLC motion tracking accounting for both target motion parallel and perpendicular to the leaf travel direction) and no compensation beam delivery. The algorithm was investigated using a synthetic motion trace with a baseline drift and four patient-measured 3D tumor motion traces representing regular and irregular motions with varying baseline drifts. Each motion trace was reproduced by a moving platform. The delivery efficiency, geometric accuracy, and dosimetric accuracy were evaluated for conformal, step-and-shoot IMRT, and dynamic sliding window IMRT treatment plans using the synthetic and patient motion traces. The dosimetric accuracy was quantified via a tgamma-test with a 3%/3 mm criterion. The delivery efficiency ranged from 89 to 100% for moving average tracking, 26%-100% for real-time tracking, and 100% (by definition) for no compensation. The root-mean-square geometric error ranged from 3.2 to 4.0 mm for moving average tracking, 0.7-1.1 mm for real-time tracking, and 3.7-7.2 mm for no compensation. The percentage of dosimetric points failing the gamma-test ranged from 4 to 30% for moving average tracking, 0%-23% for real-time tracking, and 10%-47% for no compensation. The delivery efficiency of

  9. TH-AB-202-03: A Novel Tool for Computing Deliverable Doses in Dynamic MLC Tracking Treatments

    International Nuclear Information System (INIS)

    Fast, M; Kamerling, C; Menten, M; Nill, S; Oelfke, U; Crijns, S; Raaymakers, B

    2016-01-01

    Purpose: In tracked dynamic multi-leaf collimator (MLC) treatments, segments are continuously adapted to the target centroid motion in beams-eye-view. On-the-fly segment adaptation, however, potentially induces dosimetric errors due to the finite MLC leaf width and non-rigid target motion. In this study, we outline a novel tool for computing the 4d dose of lung SBRT plans delivered with MLC tracking. Methods: The following automated workflow was developed: A) centroid tracking, where the initial segments are morphed to each 4dCT phase based on the beams-eye-view GTV shift (followed by a dose calculation on each phase); B) re-optimized tracking, in which all morphed initial plans from (A) are further optimised (“warm-started”) in each 4dCT phase using the initial optimisation parameters but phase-specific volume definitions. Finally, both dose sets are accumulated to the reference phase using deformable image registration. Initial plans were generated according to the RTOG-1021 guideline (54Gy, 3-Fx, equidistant 9-beam IMRT) on the peak-exhale (reference) phase of a phase-binned 4dCT. Treatment planning and delivery simulations were performed in RayStation (research v4.6) using our in-house segment-morphing algorithm, which directly links to RayStation through a native C++ interface. Results: Computing the tracking plans and 4d dose distributions via the in-house interface takes 5 and 8 minutes respectively for centroid and re-optimized tracking. For a sample lung SBRT patient with 14mm peak-to-peak motion in sup-inf direction, mainly perpendicular leaf motion (0-collimator) resulted in small dose changes for PTV-D95 (−13cGy) and GTV-D98 (+18cGy) for the centroid tracking case compared to the initial plan. Modest reductions of OAR doses (e.g. spinal cord D2: −11cGy) were achieved in the idealized tracking case. Conclusion: This study presents an automated “1-click” workflow for computing deliverable MLC tracking doses in RayStation. Adding a non

  10. Induction of mitotic micronuclei by X-ray contrast media in human peripheral lymphocytes

    International Nuclear Information System (INIS)

    Parvez, Z.; Moncada, R.; Kormano, M.; Satokari, K.; Eklund, R.

    1987-01-01

    In vitro and in vivo cytogenetic effects of X-ray contrast media (CM) were determined by scoring micronuclei (MN) in 72-h cultures of human peripheral lymphocytes. Both ionic (sodium meglumine diatrizoate, methylglucamine diatrizoate, and sodium meglumine ioxaglate and nonionic CM (iosimide, iopromide, iohexol and iotrolan) were able to induce MN in lymphocytes. Based upon their calculated percent probabilities for MN induction, these agents could be ranked in their decreasing order of probability, as iosimide > sodium meglumine ioxaglate > iohexol > sodium meglumine diatrizoate > iopromide > methylglucamine diatrizoate > iotrolan. Stepwise logistic regression analysis of the data indicated that the frequency of MN in CM-exposed lymphocyte cultures was significantly higher than the frequency of MN in control cultures (P < 0.001). In clinical studies where 14 patients were injected with an ionic CM methylglucamine diatrizoate, lymphocyte cultures from 10 patients showed higher frequencies of MN. The differences between pre- and post-CM counts of MN were significant in a Mann-Whitney U test (P < 0.05). The effect of X-irradiation on MN formation in lymphocytes was separately determined and was found to be insignificant. These results indicate that irrespective of ionic and osmolality differences, X-ray contrast agents are capable of producing chromosomal damage in peripheral lymphocytes. Further studies are required to establish molecular mechanisms in the observed cytogenetic effects of CM in cell cultures. (Auth.)

  11. Radioprotective effect of flavonoid quercetin on human lymphocytic cells

    International Nuclear Information System (INIS)

    Siqueira, Williams N.; Melo, Larissa S.A.; Lima, Maíra V.; Luna Filho, Ricardo L.C.; Melo, Ana M.M.A.; Silva, Edvane B.

    2017-01-01

    Several substances of synthetic and natural origin have been studied in relation to their ability to protect the body from damage caused by ionizing radiation. Among these substances, quercetin has been shown to be a molecule of natural origin with high radioprotective potential due to its antioxidant properties. The objective of this study was to determine, in vitro, the radioprotective effect of quercetin on human lymphocytes exposed to gamma radiation. Blood was irradiated at the 2.5, 3.5 and 4.5 Gy doses and then lymphocyte culture with quercetin at preselected concentrations of 37.5 and 75 μM. Subsequently, slides were prepared for analysis and quantification of the metaphases present in lymphocyte cells. The results demonstrated that irradiated lymphocytes and later exposed to quercetin presented a lower number of chromosomal alterations compared to the control group which was irradiated and not exposed to quercetin. Therefore, the results suggest a radioprotective effect of flavonoid quercetin on human lymphocytes exposed, in vitro, to ionizing radiation

  12. Application of a new ultra-microculture system. II. Stimulation of human B lymphocytes.

    Science.gov (United States)

    Ulmer, A J; Gruber, M; Flad, H D

    1988-07-22

    An ultra-microtechnique for culturing human B-lymphocytes in glass capillary tubes using a volume of 2 microliter is described. The advantage of this ultra-microculture system is that only a small number of lymphocytes and minute amounts of culture medium (or test factors) are required. Optimal culture conditions for the formation of Ig-secreting plaque-forming cells (PFC) after stimulation of mononuclear cells with pokeweed mitogen are given. Furthermore it is shown that immunoglobulin secreted into culture supernatants by purified B cells in the presence of T cell subsets can be measured in a microELISA.

  13. Monte Carlo modeling and simulations of the High Definition (HD120) micro MLC and validation against measurements for a 6 MV beam

    International Nuclear Information System (INIS)

    Borges, C.; Zarza-Moreno, M.; Heath, E.; Teixeira, N.; Vaz, P.

    2012-01-01

    Purpose: The most recent Varian micro multileaf collimator (MLC), the High Definition (HD120) MLC, was modeled using the BEAMNRC Monte Carlo code. This model was incorporated into a Varian medical linear accelerator, for a 6 MV beam, in static and dynamic mode. The model was validated by comparing simulated profiles with measurements. Methods: The Varian Trilogy (2300C/D) accelerator model was accurately implemented using the state-of-the-art Monte Carlo simulation program BEAMNRC and validated against off-axis and depth dose profiles measured using ionization chambers, by adjusting the energy and the full width at half maximum (FWHM) of the initial electron beam. The HD120 MLC was modeled by developing a new BEAMNRC component module (CM), designated HDMLC, adapting the available DYNVMLC CM and incorporating the specific characteristics of this new micro MLC. The leaf dimensions were provided by the manufacturer. The geometry was visualized by tracing particles through the CM and recording their position when a leaf boundary is crossed. The leaf material density and abutting air gap between leaves were adjusted in order to obtain a good agreement between the simulated leakage profiles and EBT2 film measurements performed in a solid water phantom. To validate the HDMLC implementation, additional MLC static patterns were also simulated and compared to additional measurements. Furthermore, the ability to simulate dynamic MLC fields was implemented in the HDMLC CM. The simulation results of these fields were compared with EBT2 film measurements performed in a solid water phantom. Results: Overall, the discrepancies, with and without MLC, between the opened field simulations and the measurements using ionization chambers in a water phantom, for the off-axis profiles are below 2% and in depth-dose profiles are below 2% after the maximum dose depth and below 4% in the build-up region. On the conditions of these simulations, this tungsten-based MLC has a density of 18.7 g

  14. Lymphocyte as a biological dosimeter : a different approach

    International Nuclear Information System (INIS)

    Madhvanath, U.

    1974-01-01

    Chromosome aberration frequency as a measure of radiation exposure in human blood lymphocytes following a short term culture is well known and the technique is in use at several laboratories in the world to determine accidental exposures. Results of an entirely different approach to arrive at the exposure is presented. Time course of interphase death of human peripheral blood lymphocytes was followed for 6 days after exposure to cobalt-60 gamma radiation. Trypan blue dye exclusion method was used for scoring viable cells. Survival curves at 5 days post irradiation were exponential and had two components: an initial sensitive component representing a major sub-population of lymphocytes with a mean lethal dose (DO) of 75 rads and the other an apparently more resistant population with a Do of about 300 rads. The initial part of the survival curve which spans to about 100 rads reaching a survival level of 15 percent, can be used to read off the extent of exposure in accident cases. Although 60 percent of the initial lymphocytes survive in the unexposed control cultures, the method is sensitive to exposures of the order of 20 rads and reproducible results have been obtained. The response is independent of dose-rate from 65 rads/min to 65 rads/hour. Other aspects of the dosimetry system such as the neutron response, in vitro and in vivo correlation are discussed. (author)

  15. Effects of noise exposure on catalase activity of growing lymphocytes

    Directory of Open Access Journals (Sweden)

    Syed Kashif Nawaz

    2012-11-01

    Full Text Available Oxidative stress due to noise was estimated at cell level using model of growing lymphocytes. Lymphocytes were isolated and cultured using conventional methodology. Cell culture of each group was exposed to sound of frequency 1 KHz during incubation. Three groups were defined on the basis of exposure of sound with specific range of intensity and duration of exposure. Group A and Group B were exposed to sound with intensity 110 dBA for four hours per day and for eight hours per day respectively. Control group was exposed to sound less than 85 dBA. Viable cell count was performed using trypan blue. Catalase activity of each group was estimated using ELISA kit.Viable cell count of Group A and Group B was almost same but significantly less than that of control group. Catalase activity of lymphocytes in Group B was significantly low as compared to Group A and controls (p=0.003,p< 0.05. There was no significant difference between catalase activity of Group A and control group.Exposure of sound with frequency 1 KHz and intensity 110 dBA for 4 hours and eight hours per day may induce oxidative stress in growing lymphocytes causing the difference in viable cell count. However the catalase activity depends on duration of exposure. In case of noise exposure of 8 hours per day, it declines significantly as compared to noise exposure of 4 hours per day.

  16. Comparison of conventional inserts and an add-on electron MLC for chest wall irradiation of left-sided breast cancer

    International Nuclear Information System (INIS)

    Vatanen, Tero; Lahtinen, Tapani; Traneus, Erik

    2009-01-01

    Background. Collimation of irregularly shaped clinical electron beams is currently based on electron inserts made of low melting point alloys. The present investigation compares a conventional electron applicator with insert and add-on eMLC-based dose distributions in the postoperative chest wall irradiation of left-sided breast cancer. Material and methods. Voxel Monte Carlo++ (VMC++) calculated dose distributions related to electron fields were compared with 10 left-sided breast cancer patients after radical mastectomy. The prescription dose was 50 Gy at a build-up maximum. The same dose was prescribed for the ipsilateral axillary, parasternal and supraclavicular lymph nodes that were treated with photons and calculated with a pencil beam algorithm. The insert beams were shaped with 1.5 cm thick Wood's metal electron inserts in an electron applicator of a Varian 2100 C/D linac. Doses for the eMLC-shaped beams were calculated for an eMLC prototype with 2 cm thick and 5 mm wide steel leaves. The same collimator-to-surface distance (CSD) of 5.8 cm was used for both collimators. Results. The mean PTV dose was slightly higher for the eMLC plans (50.7 vs 49.5 Gy, p<0.001, respectively). The maximum doses assessed by D5% for the eMLC and insert were 60.9 and 59.1 Gy (p<0.001). The difference was due to the slightly higher doses near the field edges for the eMLC. The left lung V20 volumes were 34.5% and 34.0% (p<0.001). There was only a marginal difference in heart doses. Discussion: Despite a slight increase of maximum dose in PTV the add-on electron MLC for chest wall irradiation results in practically no differences in dose distributions compared with the present insert-based collimation

  17. Drastic increase of myosin light chain MLC-2 in senescent skeletal muscle indicates fast-to-slow fibre transition in sarcopenia of old age.

    Science.gov (United States)

    Gannon, Joan; Doran, Philip; Kirwan, Anne; Ohlendieck, Kay

    2009-11-01

    The age-dependent decline in skeletal muscle mass and function is believed to be due to a multi-factorial pathology and represents a major factor that blocks healthy aging by increasing physical disability, frailty and loss of independence in the elderly. This study has focused on the comparative proteomic analysis of contractile elements and revealed that the most striking age-related changes seem to occur in the protein family representing myosin light chains (MLCs). Comparative screening of total muscle extracts suggests a fast-to-slow transition in the aged MLC population. The mass spectrometric analysis of the myofibril-enriched fraction identified the MLC2 isoform of the slow-type MLC as the contractile protein with the most drastically changed expression during aging. Immunoblotting confirmed an increased abundance of slow MLC2, concomitant with a switch in fast versus slow myosin heavy chains. Staining of two-dimensional gels of crude extracts with the phospho-specific fluorescent dye ProQ-Diamond identified the increased MLC2 spot as a muscle protein with a drastically enhanced phosphorylation level in aged fibres. Comparative immunofluorescence microscopy, using antibodies to fast and slow myosin isoforms, confirmed a fast-to-slow transformation process during muscle aging. Interestingly, the dramatic increase in slow MLC2 expression was restricted to individual senescent fibres. These findings agree with the idea that aged skeletal muscles undergo a shift to more aerobic-oxidative metabolism in a slower-twitching fibre population and suggest the slow MLC2 isoform as a potential biomarker for fibre type shifting in sarcopenia of old age.

  18. Cytogenetic investigations of chronic lymphocytic leukemia.

    Science.gov (United States)

    Wren, Catherine; Moriarty, Helen; Marsden, Katherine; Tegg, Elizabeth

    2010-04-15

    This study aimed to determine which culture method would yield the highest culture success rate, mitotic index, banding resolution, and abnormality rate in investigation of patients with chronic lymphocytic leukemia (CLL). A range of culture techniques for conventional cytogenetic (CC) analyses was compared: 24-hour unstimulated, 72 hours incubation with additional fetal calf serum, 72 hours stimulation with interleukin 4, 72 hours stimulation with lipopolysaccharide (LPS), 72 hours stimulation with TPA (12-O-tetradecanoylphorbol 13-acetate), and 72 hours stimulation with CpG-oligonucleotide DSP30 + Interleukin-2 (IL-2). CC abnormality rates were also compared to fluorescence in situ hybridization (FISH) results using probes for CLL (LSI D13S319/13q34/CEP 12: LSI ATM/p53). Forty-five samples from 24 patients (consisting of 11 newly diagnosed and 13 previously diagnosed patients) were included. For CC, a 100.0% culture success rate was achieved (n = 45) by means of an EDTA (ethylenediaminetetraacetic acid) peripheral blood sample with an associated 62.5% CC abnormality rate (n = 24). FISH detected an abnormality rate of 75.0% (n = 24). The combined CC and FISH abnormality rate was 87.5% (n = 24). This study demonstrates that CC that uses TPA and DSP30 + IL-2 on EDTA peripheral blood is effective in the investigation of CLL and may be used as a supplement to FISH studies. Copyright 2010 Elsevier Inc. All rights reserved.

  19. Pre-clinical evaluation of an inverse planning module for segmental MLC based IMRT delivery

    International Nuclear Information System (INIS)

    Georg, Dietmar; Kroupa, Bernhard

    2002-01-01

    Phantom tests are performed for pre-clinical evaluation of a commercial inverse planning system (HELAX TMS, V 6.0) for segmented multileaf collimator (MLC) intensity modulated radiotherapy (IMRT) delivery. The optimization module has available two optimization algorithms: the target primary feasibility and the weighted feasibility algorithm, only the latter allows the user to specify weights for structures. In the first series, single beam tests are performed to evaluate the outcome of inverse planning in terms of plausibility for the following situations: oblique incidence, presence of inhomogeneities, multiple targets at different depths and multiple targets with different desired doses. Additionally, for these tests a manual plan is made for comparison. In the absence of organs at risk, both the optimization algorithms are found to assign the highest priority to low dose constraints for targets. In the second series, tests resembling clinical relevant configurations (simultaneous boost and concave target with critical organ) are performed with multiple beam arrangements in order to determine the impact of the system's configuration on inverse planning. It is found that the definition of certain segment number and segment size limitations does not largely compromise treatment plans when using multiple beams. On the other hand, these limitations are important for delivery efficiency and dosimetry. For the number of iterations and voxels per volume of interest, standard values in the system's configuration are considered to be sufficient. Additionally, it is demonstrated that precautions must be taken to precisely define treatment goals when using computerized treatment optimization. Similar phantom tests could be used for a direct dosimetric verification of all steps from inverse treatment planning to IMRT delivery. (note)

  20. In-vitro responses of T lymphocytes to poly(butylene succinate) based biomaterials.

    Science.gov (United States)

    Toso, Montree; Patntirapong, Somying; Janvikul, Wanida; Singhatanadgit, Weerachai

    2017-04-01

    Polybutylene succinate (PBSu) and PBSu/β-tricalcium phosphate (TCP) composites are biocompatible and good candidates as bone graft materials. However, little is known about the responses of T lymphocytes to these biomaterials, which play an important role in the success of bone grafting. Activated T lymphocytes were cultured onto 32 mm diameter films (PBSu/TCP films), that had previously been placed in 6-well culture plates, for 8, 24 and 72 hours. A plastic-well culture plate was used as a control surface. The effects of PBSu-based biomaterials on T lymphocytes were examined by the using flow cytometry and reverse-transcription polymerase chain reaction. These biomaterials were non-toxic to T lymphocytes, allowing their normal DNA synthesis and activation. All materials induced only transient activation of T lymphocytes, which existed no longer than 72 hours. Proportions of four main CD4/CD8 T lymphocyte subpopulations were not affected by these biomaterials. Moreover, PBSu and PBSu/TCP significantly suppressed the expression of IL-1β and IL-6 genes by 15-35% and 21-26%, respectively. In contrast, a PBSu/TCP composite (at PBSu:TCP=60:40) significantly stimulated the expression of IL-10 and IL-13 genes by 17% and 19%, respectively. PBSu and PBSu/TCP composites were non-toxic to T lymphocytes and did not induce unfavorable responses of T lymphocytes. The tested biomaterials down-regulated key proinflammatory cytokine genes and up-regulated anti-inflammatory cytokine genes in T lymphocytes. These suggest that the biomaterials studied are good candidates as bone graft materials.

  1. Evaluation of the dose calculation accuracy for small fields defined by jaw or MLC for AAA and Acuros XB algorithms.

    Science.gov (United States)

    Fogliata, Antonella; Lobefalo, Francesca; Reggiori, Giacomo; Stravato, Antonella; Tomatis, Stefano; Scorsetti, Marta; Cozzi, Luca

    2016-10-01

    Small field measurements are challenging, due to the physical characteristics coming from the lack of charged particle equilibrium, the partial occlusion of the finite radiation source, and to the detector response. These characteristics can be modeled in the dose calculations in the treatment planning systems. Aim of the present work is to evaluate the MU calculation accuracy for small fields, defined by jaw or MLC, for anisotropic analytical algorithm (AAA) and Acuros XB algorithms, relative to output measurements on the beam central axis. Single point output factor measurement was acquired with a PTW microDiamond detector for 6 MV, 6 and 10 MV unflattened beams generated by a Varian TrueBeam STx equipped with high definition-MLC. Fields defined by jaw or MLC apertures were set; jaw-defined: 0.6 × 0.6, 0.8 × 0.8, 1 × 1, 2 × 2, 3 × 3, 4 × 4, 5 × 5, and 10 × 10 cm 2 ; MLC-defined: 0.5 × 0.5 cm 2 to the maximum field defined by the jaw, with 0.5 cm stepping, and jaws set to: 2 × 2, 3 × 3, 4 × 4, 5 × 5, and 10 × 10 cm 2 . MU calculation was obtained with 1 mm grid in a virtual water phantom for the same fields, for AAA and Acuros algorithms implemented in the Varian eclipse treatment planning system (version 13.6). Configuration parameters as the effective spot size (ESS) and the dosimetric leaf gap (DLG) were varied to find the best parameter setting. Differences between calculated and measured doses were analyzed. Agreement better than 0.5% was found for field sizes equal to or larger than 2 × 2 cm 2 for both algorithms. A dose overestimation was present for smaller jaw-defined fields, with the best agreement, averaged over all the energies, of 1.6% and 4.6% for a 1 × 1 cm 2 field calculated by AAA and Acuros, respectively, for a configuration with ESS = 1 mm for both X and Y directions for AAA, and ESS = 1.5 and 0 mm for X and Y directions for Acuros. Conversely, a calculated dose underestimation was found for small MLC-defined fields, with the

  2. Bovine ocular squamous cell carcinoma: UV sensitivity in lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Lavin, M.F.; Jennings, P.A.; Hughes, D.J. (Queensland Univ., Brisbane (Australia))

    1982-05-01

    Increased sensitivity to UV light has been demonstrated in Phytohaemagglutinin stimulated lymphocytes from normal and tumour-bearing Hereford cattle when compared to lymphocytes from other breeds. Trypan blue exclusion and inhibition of DNA synthesis were used to determine cell viability. The results obtained from time course and radiation dose experiments demonstrate biphasic survival kinetics. This is indicative of at least two separate cell populations, exhibiting differential sensitivity to UV. The increased sensitivity to UV observed in Herefords may reflect a general sensitivity to UV or alternatively a different cellular constitution in the mitogen stimulated cultures. DNA repair synthesis, measured in the presence of hydroxyurea, was of similar levels in cell cultures from Herefords and one of the control breeds.

  3. Bovine ocular squamous cell carcinoma: UV sensitivity in lymphocytes

    International Nuclear Information System (INIS)

    Lavin, M.F.; Jennings, P.A.; Hughes, D.J.

    1982-01-01

    Increased sensitivity to UV light has been demonstrated in Phytohaemagglutinin stimulated lymphocytes from normal and tumour-bearing Hereford cattle when compared to lymphocytes from other breeds. Trypan blue exclusion and inhibition of DNA synthesis were used to determine cell viability. The results obtained from time course and radiation dose experiments demonstrate biphasic survival kinetics. This is indicative of at least two separate cell populations, exhibiting differential sensitivity to UV. The increased sensitivity to UV observed in Herefords may reflect a general sensitivity to UV or alternatively a different cellular constitution in the mitogen stimulated cultures. DNA repair synthesis, measured in the presence of hydroxyurea, was of similar levels in cell cultures from Herefords and one of the control breeds. (author)

  4. Cytogenetic evaluation of Fansidar on human lymphocyte chromosomes in vitro.

    Science.gov (United States)

    Praveen, Nuzhat; Saifi, Muheet Alam; Shadab, G G H A

    2011-01-01

    Fansidar is a fixed combination of two antimalarial agents a diaminopyrimidine (Pyrimethamine) and a sulphonamide (Sulphadoxine) in the ratio 1:20- that have been used extensively worldwide for the treatment of Chloroquine resistant Plasmodium falciparum malaria, toxoplasmosis and Pneumocystis carinii pneumonia in patients with the acquired immunodeficiency syndrome. This study examined the effect of Fansidar on chromosomes in human lymphocyte culture. Fansidar was added to peripheral blood lymphocyte cultures in vitro at four different concentrations: 5,15, 25 and 50 microl in the ratio 1:20, 3:60, 5:100 and 10:200 microg ml(-1). Result shows that this drug induces moderate increase in the frequency of gaps, breaks and rearrangements. Therefore it can be concluded that Fansidar has moderate clastogenic effect on human chromosomes in vitro.

  5. Chromosome radiosensitivity and kinetics of proliferation of peripheral lymphocytes in individuals with aneuploid karyotype

    Energy Technology Data Exchange (ETDEWEB)

    Konecna, H; Kalina, I; Ondrussekova, A

    1988-08-01

    Experimentally investigated was the radiosensitivity of chromosomes and the kinetics of the proliferation of peripheral lymphocytes in patients with aneuploid (DS and TS) and normal karyotype irradiated in vitro in the G/sub o/ stage of the cell cycle. Trisomic lymphocytes were found to proliferate more rapidly in the in vitro culture and to be more sensitive than diploid cell populations. In monosomic lymphocytes in Turner syndrome patients, the proliferation and incidence of chromosomal abberations was similar to the disomic lines in Down's syndrome patients and in Turner syndrome patients, and to that found in persons with a normal karyotype. The results of the experiment show that there is a relationship between the proliferation rate of peripheral lymphocytes cultures in vitro and the radiosensivity of chromosomes. (author). 1 tab., 3 figs., 11 refs.

  6. Chromosome radiosensitivity and kinetics of proliferation of peripheral lymphocytes in individuals with aneuploid karyotype

    International Nuclear Information System (INIS)

    Konecna, H.; Kalina, I.; Ondrussekova, A.

    1988-01-01

    Experimentally investigated was the radiosensitivity of chromosomes and the kinetics of the proliferation of peripheral lymphocytes in patients with aneuploid (DS and TS) and normal karyotype irradiated in vitro in the G o stage of the cell cycle. Trisomic lymphocytes were found to proliferate more rapidly in the in vitro culture and to be more sensitive than diploid cell populations. In monosomic lymphocytes in Turner syndrome patients, the proliferation and incidence of chromosomal abberations was similar to the disomic lines in Down's syndrome patients and in Turner syndrome patients, and to that found in persons with a normal karyotype. The results of the experiment show that there is a relationship between the proliferation rate of peripheral lymphocytes cultures in vitro and the radiosensivity of chromosomes. (author). 1 tab., 3 figs., 11 refs

  7. [The lymphocyte transformation test in dermatology].

    Science.gov (United States)

    Zinn, K; Braun-Falco, O

    1976-03-01

    At first, immunologie and methodic basies of the lymphocyte transformation test are discussed. Then the results gained by this test in several dermatologic diseases are summarized. Finally, practice of the lymphocyte transformation test is critically reviewed.

  8. SU-E-P-36: Evaluation of MLC Positioning Errors in Dynamic IMRT Treatments by Analyzing Dynalog Files

    International Nuclear Information System (INIS)

    Olasolo, J; Pellejero, S; Gracia, M; Gallardo, N; Martin, M; Lozares, S; Maneru, F; Bragado, L; Miquelez, S; Rubio, A

    2015-01-01

    Purpose: To assess the accuracy of MLC positioning in Varian linear accelerator, in dynamic IMRT technique, from the analysis of dynalog files generated by the MLC controller. Methods: In Clinac accelerators (pre-TrueBeam technology), control system has an approximately 50ms delay (one control cycle time). Then, the system compares the measured position to the planned position corresponding to the next control cycle. As it has been confirmed by Varian technical support, this effect causes that measured positions appear in dynalogs one cycle out of phase with respect to the planned positions. Around 9000 dynalogs have been analyzed, coming from the three linear accelerators of our center (one Trilogy and two Clinac 21EX) equipped with a Millennium 120 MLC. In order to compare our results to recent publications, leaf positioning errors (RMS and 95th percentile) are calculated with and without delay effect. Dynalogs have been analyzed using a in-house Matlab software. Results: The RMS errors were 0.341, 0.339 and 0.348mm for each Linac; being the average error 0.343 mm. The 95th percentiles of the error were 0.617, 0.607 and 0.625; with an average of 0.617mm. A recent multi-institution study carried out by Kerns et al. found a mean leaf RMS error of 0.32mm and a 95th percentile error value of 0.64mm.Without delay effect, mean leaf RMS errors obtained were 0.040, 0.042 and 0.038mm for each treatment machine; being the average 0.040mm. The 95th percentile error values obtained were 0.057, 0.058 and 0.054 mm, with an average of 0.056mm. Conclusion: Results obtained for the mean leaf RMS error and the mean 95th percentile were consistent with the multi-institution study. Calculated error statistics with delay effect are significantly larger due to the speed proportional and systematic leaf offset. Consequently it is proposed to correct this effect in dynalogs analysis to determine the MLC performance

  9. Treatment planning for MLC based robotic radiosurgery for brain metastases: plan comparison with circular fields and suggestions for planning strategies

    OpenAIRE

    Schmitt Daniela; El Shafie Rami; Klüter Sebastian; Arians Nathalie; Schubert Kai; Rieken Stefan; Debus Jürgen; Paul Angela

    2017-01-01

    To evaluate the possible range of application of the new InCise2 MLC for the CyberKnife M6 system in brain radiosurgery, a plan comparison was made for 10 brain metastases sized between 1.5 and 9cm3 in 10 patients treated in a single fraction each. The target volumes consist of a PTV derived by expanding the GTV by 1mm and were chosen to have diversity in the cohort regarding regularity of shape, location and the structures needed to be blocked for beam transmission in the vicinity. For each ...

  10. Effect of MLC leaf width on the planning and delivery of SMLC IMRT using the CORVUS inverse treatment planning system

    International Nuclear Information System (INIS)

    Burmeister, Jay; McDermott, Patrick N.; Bossenberger, Todd; Ben-Josef, Edgar; Levin, Kenneth; Forman, Jeffrey D.

    2004-01-01

    This study investigates the influence of multileaf collimator (MLC) leaf width on intensity modulated radiation therapy (IMRT) plans delivered via the segmented multileaf collimator (SMLC) technique. IMRT plans were calculated using the Corvus treatment planning system for three brain, three prostate, and three pancreas cases using leaf widths of 0.5 and 1 cm. Resulting differences in plan quality and complexity are presented here. Plans calculated using a 1 cm leaf width were chosen over the 0.5 cm leaf width plans in seven out of nine cases based on clinical judgment. Conversely, optimization results revealed a superior objective function result for the 0.5 cm leaf width plans in seven out of the nine comparisons. The 1 cm leaf width objective function result was superior only for very large target volumes, indicating that expanding the solution space for plan optimization by using narrower leaves may result in a decreased probability of finding the global minimum. In the remaining cases, we can conclude that we are often not utilizing the objective function as proficiently as possible to meet our clinical goals. There was often no apparent clinically significant difference between the two plans, and in such cases the issue becomes one of plan complexity. A comparison of plan complexity revealed that the average 1 cm leaf width plan required roughly 60% fewer segments and over 40% fewer monitor units than required by 0.5 cm leaf width plans. This allows a significant decrease in whole body dose and total treatment time. For very complex IMRT plans, the treatment delivery time may affect the biologically effective dose. A clinically significant improvement in plan quality from using narrower leaves was evident only in cases with very small target volumes or those with concavities that are small with respect to the MLC leaf width. For the remaining cases investigated in this study, there was no clinical advantage to reducing the MLC leaf width from 1 to 0.5 cm. In

  11. Serial tomotherapy vs. MLC-IMRT (Multileaf Collimator Intensity Modulated Radiotherapy) for simultaneous boost treatment large intracerebral lesions

    International Nuclear Information System (INIS)

    Wolff, Dirk; Lohr, Frank; Mai, Sabine; Polednik, Martin; Wenz, Frederik; Dobler, Barbara

    2009-01-01

    Introduction: Recent data suggest that a radiosurgery boost treatment for up to three brain metastases in addition to whole brain radiotherapy (WBRT) is beneficial. Sequential treatment of multiple metastatic lesions is time-consuming and optimal normal tissue sparing is not trivial for larger metastases when separate plans are created and are only superimposed afterwards. Sequential Tomotherapy with noncoplanar arcs and Multi-field IMRT may streamline the process and enable easy simultaneous treatment. We compared plans for 2-3 intracerebral targets calculated with Intensity Modulated Radiotherapy (IMRT) based on treatment with MLC or sequential Tomotherapy using the Peacock-System. Treatment time was not to exceed 90 min on a linac with standart dose rate. MIMiC plans without treatment-time restrictions were created as a benchmark. Materials and methods: Calculations are based on a Siemens KD2 linac with a dose rate of 200 MU/min. Step-and-Shoot IMRT is performed with a standard MLC (2 x 29 leaves, 1 cm), serial Tomotherapy with the Multivane-Collimator MIMiC (NOMOS Inc. USA). Treatment plans are created with Corvus 5.0. To create plans with good conformity we chose a noncoplanar beam- and arc geometry for each approach (IMRT 4-, MIMiC 5-couch angles). The benchmark MIMiC plans with maximally steep dose gradients had 9 couch angles. For plan comparison reasons, 10Gy were prescribed to 90% of the PTV. Steepness of dose gradients, homogeneity and conformity were assessed by the following parameters: Volume encompassed by certain isodoses outside the target as well as homogeneity and conformity as indicated by Homogeneity- and Conformity-Index. Results: Plans without treatment-time restrictions had slightest dose to organ at risk (OAR), normal tissue and least Conformity-index. MIMiC- and MLC-IMRT based plans can be treated within the intended period of 90 min, all plans met the required dose. MLC based plans resulted in higher dose to organs at risk (OAR) and dose

  12. Relations between the stimulation of mixed lymphocyte populations and the staging system according Rai in patients with chronic lymphatic leukemia

    International Nuclear Information System (INIS)

    Heilmann, E.; Venne, U.

    1979-01-01

    By means of the incorporation rate of 3 H thymidine into the lymphocytes of patients with chronic lymphatic leukemia the possibility of stimulating them by using different mitogens was checked and compared with normal persons. The examination covered 11 patients treated with extracorporeal irradiation of the blood (ECIB), 5 patients treated with a chlorambucil therapy, and 10 untreated patients who where classified according to the staging system proposed by Rai. The lymphocytes of the peripheral blood were stimulated as mixed and isolated T and B-lymphocytes in the microculture by using the mitogens PHA, PWM, ConA, and LPS. In all CLL patients there was a diminished stimulation rate of a mixed lymphocyte population. A relation existed between the seriousness of the stage and the deminution of the incorporation rate of 3 H thymidine. A corresponding correlation could not be identified in untreated CLL patients. Isolated T-lymphocytes revealed better results of stimulation than the total population. As to their function B-lymphocytes showed a dependence on the kind of therapy. In the mixed lymphocyte culture of normal persons the best findings could be observed after stimulation with PHA, that is also valid for CLL patients. PHA, PWA, ConA, and LPS were suitable as substances stimulating B-lymphocytes with different efficacy in normal persons and CLL patients. Both collectives showed the best results in the T-lymphocyte culture after stimulation with LPS. (author)

  13. Post-irradiation treatment of human lymphocytes with spermidine reduced frequency of chromatid breaks

    International Nuclear Information System (INIS)

    Bocian, E.; Rosiek, O.; Ziemba-Zoltowska, B.

    1978-01-01

    Human lymphocyte cultures were X-irradiated with a single dose of 100 or 200 rad 46 h after phytohemagglutinin stimulation. In dose-fractionation experiments, 2h later the second dose was applied. All the cultures were harvested at 54 h after their initiation. In lymphocytes irradiated with a single dose of 200 rad, 2h post-irradiation contact with 10 -5 M exogeneous spermidine resulted in reduction of chromatid breaks by 34 %. Introduction of spermidine into culture medium for fractionation interval between the 2 doses of 100 rad reduced the frequency of chromatid breaks by 42 %. (author)

  14. Soluble lymphocytic mediators

    Science.gov (United States)

    Pick, E.

    1974-01-01

    The effect of a number of drugs on the production of macrophage migration inhibitory factor (MIF) by antigen-stimulated sensitized guinea-pig lymph node cells was studied. The drugs were present during the entire culture period and eliminated from supernatants by dialysis. It was found that MIF secretion is inhibited by exogenous dibutyryl cyclic AMP and by theophylline and chlorphenesin, two agents raising the endogenous level of cyclic AMP. On the other hand, isoproterenol, which stimulates cyclic AMP generation in several tissues, did not block MIF production. The formation of the mediator was also suppressed by the microfilament-affecting drug, cytochalasin B. The microtubular disruptive agents, colchicine and vinblastine sulphate, did not influence MIF production. It is concluded that: (a) endogenous cyclic AMP may act as a regulator of MIF production; (b) the activity of contractile microfilaments is probably required for MIF formation; and (c) microtubules are not involved in the secretory process. PMID:4369184

  15. Lymphocytes accelerate epithelial tight junction assembly: role of AMP-activated protein kinase (AMPK.

    Directory of Open Access Journals (Sweden)

    Xiao Xiao Tang

    2010-08-01

    Full Text Available The tight junctions (TJs, characteristically located at the apicolateral borders of adjacent epithelial cells, are required for the proper formation of epithelial cell polarity as well as for sustaining the mucosal barrier to the external environment. The observation that lymphocytes are recruited by epithelial cells to the sites of infection [1] suggests that they may play a role in the modulation of epithelial barrier function and thus contribute to host defense. To test the ability of lymphocytes to modulate tight junction assembly in epithelial cells, we set up a lymphocyte-epithelial cell co-culture system, in which Madin-Darby canine kidney (MDCK cells, a well-established model cell line for studying epithelial TJ assembly [2], were co-cultured with mouse lymphocytes to mimic an infection state. In a typical calcium switch experiment, the TJ assembly in co-culture was found to be accelerated compared to that in MDCK cells alone. This accelaration was found to be mediated by AMP-activated protein kinase (AMPK. AMPK activation was independent of changes in cellular ATP levels but it was found to be activated by the pro-inflammatory cytokine TNF-alpha. Forced suppression of AMPK, either with a chemical inhibitor or by knockdown, abrogated the accelerating effect of lymphocytes on TJ formation. Similar results were also observed in a co-culture with lymphocytes and Calu-3 human airway epithelial cells, suggesting that the activation of AMPK may be a general mechanism underlying lymphocyte-accelerated TJ assembly in different epithelia. These results suggest that signals from lymphocytes, such as cytokines, facilitate TJ assembly in epithelial cells via the activation of AMPK.

  16. Lymphocyte receptors for pertussis toxin

    Energy Technology Data Exchange (ETDEWEB)

    Clark, C.G.; Armstrong, G.D. (Univ. of Alberta, Edmonton (Canada))

    1990-12-01

    We have investigated human T-lymphocyte receptors for pertussis toxin by affinity isolation and photoaffinity labeling procedures. T lymphocytes were obtained from peripheral human blood, surface iodinated, and solubilized in Triton X-100. The iodinated mixture was then passed through pertussis toxin-agarose, and the fractions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Autoradiography of the fixed, dried gels revealed several bands in the pertussis toxin-bound fraction that were not observed in fractions obtained from histone or fetuin-agarose. Further investigations employed a photoaffinity labeling reagent, sulfosuccinimidyl 2-(p-azido-salicylamido)-1,3'-dithiopropionate, to identify pertussis toxin receptors in freshly isolated peripheral blood monocytic cells, T lymphocytes, and Jurkat cells. In all three cell systems, the pertussis toxin affinity probe specifically labeled a single protein species with an apparent molecular weight of 70,000 that was not observed when the procedure was performed in the presence of excess unmodified pertussis toxin. A protein comparable in molecular weight to the one detected by the photoaffinity labeling technique was also observed among the species that bound to pertussis toxin-agarose. The results suggest that pertussis toxin may bind to a 70,000-Da receptor in human T lymphocytes.

  17. Autoreactive lymphocytes in thyroid disorders. 2

    International Nuclear Information System (INIS)

    Petersen, J.; Feldt-Rasmussen, U.; Siersbaek-Nielsen, K.; Hoeier-Madsen, M.; Larsen, F.; Husby, S.

    1986-01-01

    Blood mononuclear cells (MNC) from 9 randomly selected patients with autoimmune thyroiditis were stimulated in vitro with pokeweed mitogen (PWM), a polyclonal B lymphocyte activator. The secretion of immunoglobulins (Ig) and anti-thyroglobulin antibodies (TgAb) was assayed by means of haemolytic plaque-forming cell (PFC) assays, radioimmune assay (RIA) and enzyme-linked immunosorbent assays (ELISA). Total Ig and TgAb production was maximal using MNC cultured at 1.0 x 10 6 /ml as estimated by PFC, RIA and ELISA. The Ig and TgAb production as measured by RIA and ELISA was 1.5 - 3 times higher after 12 days' culture compared to 6 days' culture. Ig and TgAb production measured by PFC-assays at day 6 correlated positively to the results obtained by RIA and ELISA at day 12. PWM-induced TgAb secretion correlated positively to TgAb titres in serum. As judged by PFC, TgAb production was found in 8/9 patients; about 5% (range 0 - 7.9%) of the total PWM-stimulated IgG-secreting cells were involved in TgAb secretion. TgAb production as measured by ELISA and RIA was found in 6/9 patients. By reference to an affinity-purified human TgAb preparation, the TgAb secretion was about 0.7% (range 0 - 21.3%) of the total PWM-induced IgG secretion. (author)

  18. Radiosensitivity of lymphocytes among Filipinos: final report

    International Nuclear Information System (INIS)

    Medina, F.I.S.; Gregorio, J.S.; Aguilar, C.P.; Poblete, E.E.

    1996-01-01

    This report is about the studies on the radiosensitivity of Filipino lymphocytes to radiation that can elucidate on the potential of blood chromosomes as biological dosimeters. The objective of this study is to determine the radiosensitivity of lymphocytes among Filipinos and to establish the radiation-induced chromosome anomaly standard curve in lymphocytes for radiological dosimetry. 47 refs., 9 figs., 1 tab

  19. Short-term effects of regional irradiation on lymphocytes, T lymphocytes and eosinophils

    International Nuclear Information System (INIS)

    Chazarin, C.; Roche, H.; Bugat, R.; Pris, F.

    1983-01-01

    Twenty-three cancer patients treated only by regional irradiation were studied. Radiotherapy was delivered to the pelvis in 14 patients and to the mediastinum in 9. T lymphocytes were evaluated with the Jondal technique. Before treatment, lymphocyte counts were identical in patients and control. Decreases in total lymphocytes and T lymphocytes became significant in both groups after 40 Gy. Significant rises in eosinophil counts were found only after abdominal irradiation and seemed unrelated to variations in lymphocyte counts [fr

  20. Production of C-reactive protein by human lymphocytes

    International Nuclear Information System (INIS)

    Kuta, A.E.; Baum, L.L.

    1986-01-01

    C-reactive protein (CRP) is a major acute phase serum protein in humans; it is detectable at very high concentrations during infection and tissue trauma. This protein is a pentame composed of five identical, 21,500 MW subunits. CRP is detectable on the surface of approximately 4% of normal peripheral blood lymphocytes (PBL). CRP binds its physiological ligands in a Ca ++ dependent manner; removal of Ca ++ does not alter the expression of CRP on the lymphocyte surface. Recently, investigators in this laboratory reported substantial inhibition of natural killer cell (NK) activity with anti-CRP antibodies. The following studies were undertaken to determine the origin of surface-CRP (S-CRP) found on normal PBL. Cells were incubated in methionine-free DMEM supplemented with 35 S-methionine. Cells were lysed and subjected to immunoprecipitation with anti-CRP and Staphylococcus aureus; immunoprecipitates were analyzed by SDS-PAGE and autoradiography. Data presented here suggested that lymphocytes, in particular, LGL produce small amounts of CRP and express it on their surface. Lymphocytes do not appear to secrete CRP since no CRP could be detected in culture supernatants. In addition, preliminary evidence indicates that peripheral blood monocytes produce no detectable CRP. Present studies utilizing Northern blot analysis are underway in order to detect CRP-mRNA

  1. Radiosensitivity of peripheral blood lymphocytes in autoimmune disease

    Energy Technology Data Exchange (ETDEWEB)

    Harris, G [Kennedy Inst. of Rheumatology, London (UK). Div. of Experimental Pathology; Cramp, W A; Edwards, J C; George, A M; Sabovljev, S A; Hart, L; Hughes, G R.V. [Hammersmith Hospital, London (UK); Denman, A M [Northwich Park Hospital, Harrow (UK); Yatvin, M B [Wisconsin Clinical Cancer Center, Madison (USA)

    1985-06-01

    The proliferation of peripheral blood lymphocytes, cultured with Con A, can be inhibited by ionizing radiation. Lymphocytes from patients with conditions associated with autoimmunity, such as rheumatoid arthritis, systemic lupus erythematosus and polymyositis, are more radiosensitive than those from healthy volunteers or patients with conditions not associated with autoimmunity. Nuclear material isolated from the lymphocytes of patients with autoimmune diseases is, on average, lighter in density than the nuclear material from most healthy controls. This difference in density is not related to increased sensitivity to ionizing radiation but the degree of post-irradiation change in density (lightening) is proportional to the initial density, i.e. more dense nuclear material always shows a greater upward shift after radiation. The recovery of pre-irradiation density of nuclear material, 1 h after radiation exposure, taken as an indication of DNA repair, correlates with the radiosensitivity of lymphocyte proliferation (Con A response); failure to return to pre-irradiation density being associated with increased sensitivity of proliferative response. These results require extension but, taken with previously reported studied of the effects of DNA methylating agents, support the idea that DNA damage and its defective repair could be important in the aetio-pathogenesis of autoimmune disease.

  2. Survival of human lymphocytes after exposure to densely ionizing radiations

    International Nuclear Information System (INIS)

    Madhvanath, U.; Raju, M.R.; Kelly, L.S.

    1976-01-01

    Interphase death of human blood lymphocytes cultured in vitro was studied after exposure to 60 Co gamma rays and to accelerated ions of 1 H, 4 He, 7 Li, 11 B, 12 C, 20 Ne, 40 Ar, and π - meson beam under aerobic conditions. Exposures were also conducted under hypoxic conditions with 60 Co gamma rays, 4 He, 7 Li, and 12 C ion beams. Time course of interphase death was followed for 6 days after irradiation. Percent survivals were determined by using the trypan blue exclusion method. Survival curves at 5 days postirradiation were exponential for all radiations studied. These observations indicate that the production of interphase death of lymphocytes by densely ionizing radiations follows a pattern similar to that observed with colony-forming mammalian cells. However, the reproductive capacity of the latter cells is impaired with maximum effectiveness at energy densities associated with 220 keV/μm for the beam conditions used in this investigation. The much lower energy densities required to kill a lymphocyte suggest that a sensitive structure other than DNA may be responsible for the production of lymphocyte death, perhaps the membranes. The calculated inactivation cross sections for high-LET radiations above 650 keV/μm yielded values larger than the actual cell dimensions. It appears that contributions from delta rays become appreciable in this system at these LET's

  3. Asymmetric Programming: A Highly Reliable Metadata Allocation Strategy for MLC NAND Flash Memory-Based Sensor Systems

    Science.gov (United States)

    Huang, Min; Liu, Zhaoqing; Qiao, Liyan

    2014-01-01

    While the NAND flash memory is widely used as the storage medium in modern sensor systems, the aggressive shrinking of process geometry and an increase in the number of bits stored in each memory cell will inevitably degrade the reliability of NAND flash memory. In particular, it's critical to enhance metadata reliability, which occupies only a small portion of the storage space, but maintains the critical information of the file system and the address translations of the storage system. Metadata damage will cause the system to crash or a large amount of data to be lost. This paper presents Asymmetric Programming, a highly reliable metadata allocation strategy for MLC NAND flash memory storage systems. Our technique exploits for the first time the property of the multi-page architecture of MLC NAND flash memory to improve the reliability of metadata. The basic idea is to keep metadata in most significant bit (MSB) pages which are more reliable than least significant bit (LSB) pages. Thus, we can achieve relatively low bit error rates for metadata. Based on this idea, we propose two strategies to optimize address mapping and garbage collection. We have implemented Asymmetric Programming on a real hardware platform. The experimental results show that Asymmetric Programming can achieve a reduction in the number of page errors of up to 99.05% with the baseline error correction scheme. PMID:25310473

  4. Evaluation of the dosimetric consequences of adding a single asymmetric or MLC shaped field to a tangential breast radiotherapy technique

    International Nuclear Information System (INIS)

    Richmond, Neil D.; Turner, Robert N.; Dawes, Peter J.D.K.; Lambert, Geoff D.; Lawrence, Gill P.

    2003-01-01

    Fifteen consecutive patients had standard treatment plans generated using our departmental protocol and two further plans produced using either an asymmetric, or MLC shaped additional field, from each tangential direction. The mean percentage of the PTV receiving over 107% of the isocentre dose was 19.8% for the standard planned patients (95% confidence interval 12.3-27.4%). This was reduced to 6.0% for the asymmetric field technique (95% confidence interval 4.1-8.0%) and 5.3% for the MLC technique (95% confidence interval 2.8-7.7%). These high dose volume reductions were therefore significant at the 95% confidence level. It was also concluded that both alternative planning techniques offer the greatest potential when the standard plan indicated that more than 20% of the PTV would receive greater than 107% of the prescribed dose. Under these circumstances the segmented field techniques led to a reduction of at least 15 percentage points in this figure. It is this group of patients who stand to benefit most from application of these simple additional field techniques

  5. Asymmetric Programming: A Highly Reliable Metadata Allocation Strategy for MLC NAND Flash Memory-Based Sensor Systems

    Directory of Open Access Journals (Sweden)

    Min Huang

    2014-10-01

    Full Text Available While the NAND flash memory is widely used as the storage medium in modern sensor systems, the aggressive shrinking of process geometry and an increase in the number of bits stored in each memory cell will inevitably degrade the reliability of NAND flash memory. In particular, it’s critical to enhance metadata reliability, which occupies only a small portion of the storage space, but maintains the critical information of the file system and the address translations of the storage system. Metadata damage will cause the system to crash or a large amount of data to be lost. This paper presents Asymmetric Programming, a highly reliable metadata allocation strategy for MLC NAND flash memory storage systems. Our technique exploits for the first time the property of the multi-page architecture of MLC NAND flash memory to improve the reliability of metadata. The basic idea is to keep metadata in most significant bit (MSB pages which are more reliable than least significant bit (LSB pages. Thus, we can achieve relatively low bit error rates for metadata. Based on this idea, we propose two strategies to optimize address mapping and garbage collection. We have implemented Asymmetric Programming on a real hardware platform. The experimental results show that Asymmetric Programming can achieve a reduction in the number of page errors of up to 99.05% with the baseline error correction scheme.

  6. Effect of MLC Leaf Width and PTV Margin on the Treatment Planning of Intensity-Modulated Stereotactic Radiosurgery (IMSRS) or Radiotherapy (IMSRT)

    International Nuclear Information System (INIS)

    Chang Jenghwa; Yenice, Kamil M.; Jiang Kailiu; Hunt, Margie; Narayana, Ashwatha

    2009-01-01

    We studied the effect of MLC (multileaf collimator) leaf width and PTV (planning target volume) margin on treatment planning of intensity modulated stereotactic radiosurgery (IMSRS) or radiotherapy (IMSRT). Twelve patients previously treated with IMSRS/IMSRT were retrospectively planned with 5- and 3-mm MLC leaf widths and 3- and 2-mm PTV margins using the already contoured clinical target volume and critical structures. The same beam arrangement, planning parameters, and optimization method were used in each of the 4 plans for a given patient. Each plan was normalized so that the prescription dose covered at least 99% of the PTV. Plan indices - D mean (mean dose), conformity index (CI), V 70 (volume receiving ≥ 70% of the prescription dose), and V 50 (volume receiving ≥ 50% of the prescription dose) - were calculated from the dose-volume histograms (DVHs) of the PTV, normal tissue, and organs at risk (OARs). Hypothesis testing was performed on the mean ratios of plan indices to determine the statistical significance of the relative differences. The PTV was well covered for all plans, as no significant differences were observed for D 95 , V 95 , D max , D min , and D mean of the PTV. The irradiated volume was ∼23% smaller when 2-mm instead of 3-mm PTV margin was used, but it was only reduced by ∼6% when the MLC leaf width was reduced from 5 mm to 3 mm. For normal tissue and brainstem, V 70 , V 50 , and D mean were reduced more effectively by a decrease in MLC width, while D mean of optic nerve and chiasm were more sensitive to a change in PTV margin. The DVH statistics for the PTV and normal structures from the treatment plan with 5-mm MLC and 2-mm PTV margin were equal to those with 3-mm MLC and 3-mm PTV margin. PTV margin reduction is more effective in sparing the normal tissue and OARs than a reduction in MLC leaf width. For IMSRS, where highly accurate setup and small PTV margins are routinely employed, the use of 5-mm MLC is therefore less desirable.

  7. Efficacy and Safety of MLC601 in the Treatment of Mild Cognitive Impairment: A Pilot, Randomized, Double-Blind, Placebo-Controlled Study

    Directory of Open Access Journals (Sweden)

    Hossein Pakdaman

    2017-05-01

    Full Text Available Background and Aim: Mild cognitive impairment (MCI is characterized by declined cognitive function greater than that expected for a person’s age. The clinical significance of this condition is its possible progression to dementia. MLC601 is a natural neuroprotective medication that has shown promising effects in Alzheimer disease. Accordingly, we conducted this randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of MLC601 in MCI patients. Methods: Seventy-two patients with a diagnosis of MCI were recruited. The included participants were randomly assigned to groups to receive either MLC601 or placebo. An evaluation of global cognitive function was performed at baseline as well as at 3-month and 6-month follow-up visits. Global cognitive function was assessed by Mini-Mental State Examination (MMSE and Alzheimer’s Disease Assessment Scale-cognitive subscale (ADAS-cog scores. Efficacy was evaluated by comparing global function scores between the 2 groups during the study period. Safety assessment included adverse events (AEs and abnormal laboratory results. Results: Seventy patients completed the study, 34 in the MLC601 group and 36 in the placebo group. The mean changes (±SD in cognition scores over 6 months in the MLC601 group were –2.26 (±3.42 for the MMSE and 3.82 (±6.16 for the ADAS-cog; in the placebo group, they were –2.66 (±3.43 for the MMSE and 4.41 (±6.66 for the ADAS-cog. The cognition changes based on both MMSE and ADAS-cog scores were statistically significant between the placebo and the MLC601 group (p < 0.001. Only 5 patients (14.7% reported minor AEs in the MLC601 group, the most commonly reported of which were gastrointestinal, none of them leading to patient withdrawal. Conclusion: MLC601 has shown promising efficacy and acceptable AEs in MCI patients.

  8. The effect of electron collimator leaf shape on the build-up dose in narrow electron MLC fields

    International Nuclear Information System (INIS)

    Vatanen, T; Vaeaenaenen, A; Lahtinen, T; Traneus, E

    2009-01-01

    Previously, we have found that the build-up dose from abutting narrow electron beams formed with unfocussed electron multi-leaf collimator (eMLC) steal leaves was higher than with the respective open field. To investigate more closely the effect of leaf material and shape on dose in the build-up region, straight, round (radius 1.5 cm) and leaf ends with a different front face angle of α (leaf front face pointing towards the beam axis at an angle of 90 - α) made of steel, brass and tungsten were modelled using the BEAMnrc code. Based on a treatment head simulation of a Varian 2100 C/D linac, depth-dose curves and profiles in water were calculated for narrow 6, 12 and 20 MeV eMLC beams (width 1.0 cm, length 10 cm) at source-to-surface distances (SSD) of 102 and 105 cm. The effects of leaf material and front face angle were evaluated based on electron fluence, angle and energy spectra. With a leaf front face angle of 15 deg., the dose in the build-up region of the 6 MeV field varied between 91 and 100%, while for straight and round leaf shapes the dose varied between 89 and 100%. The variation was between 94 and 100% for 12 and 20 MeV. For abutting narrow 6 MeV fields with total field size 5 x 10 cm 2 , the build-up doses at 5 mm depth for the face angle 15 deg. and straight and round leaf shapes were 96% and 86% (SSD 102 cm) and 89% and 85% (SSD 105 cm). With higher energies, the effect of eMLC leaf shape on dose at 5 mm was slight (3-4% units with 12 MeV) and marginal with 20 MeV. The fluence, energy and angle spectra for total and leaf scattered electrons were practically the same for different leaf materials with 6 MeV. With high energies, the spectra for tungsten were more peaked due to lower leaf transmission. Compared with straight leaf ends, the face angle of 15 deg. and round leaf ends led to a 1 mm (for 6 MeV) and between 1 and 5 mm (12 and 20 MeV at a SSD of 105 cm) decrease of therapeutic range and increase of the field size, respectively. However

  9. Inhibitory serum factor of lymphoproliferative response to allogeneic cells in pregnancy

    Directory of Open Access Journals (Sweden)

    Silvia Daher

    Full Text Available INTRODUCTION: An inhibitory serum factor of mixed lymphocyte culture (MLC has been associated with successful pregnancy after lymphocyte transfusion in women with unexplained recurrent spontaneous abortions (RSA. OBJECTIVE: Investigate whether the inhibitory serum factor of MLC is essential for a successful pregnancy. METHOD: Sera from 33 healthy pregnant women and from 40 women with RSA were assessed by a one-way MLC in which the woman's lymphocytes were stimulated with her partner's lymphocytes or with third party lymphocytes. RESULTS: An inhibitory serum effect (inhibition > 50% as compared to normal serum was detected in 45% of the pregnant women who had at least 1 previous parity, in 8% of the primigravidea, in 29% of those with one abortion and in 58% of those with more than one abortion. CONCLUSION: MLC inhibitory serum factor does not seem to be an essential factor for pregnancy development. Therefore, it should not be considered as a parameter for the assessment of RSA patients.

  10. Nonspecific activation of murine lymphocytes. IV. Proliferation of a distinct, late maturing lymphocyte subpopulation induced by 2-mercaptoethanol

    International Nuclear Information System (INIS)

    Goodman, M.G.; Fidler, J.M.; Weigle, W.O.

    1978-01-01

    The lymphocyte subpopulations that are activated by 2-ME, LPS, poly IC, and PPD were studied in terms of their maturational characteristics. Attempts to stimulate hepatic and splenic lymphoid cells from mice of different ages with these mitogens demonstrated a well ordered sequence for the emergency of mitogen responsiveness in C3H mice: reactivity to LPS and Poly IC was observed early in maturation and was followed by that to PPD, and finally by the development of responsiveness to 2-ME. The same sequence appeared when the mitogen responsiveness of lethally irradiated, fetal liver-reconstituted syngeneic adult recipients was examined. The mitogenic action of 2-ME was dissociated from its ability to enhance lymphocyte reactivity to other mitogens in mice too young to respond to 2-ME as a mitogen. Experiments in which additivity of responses was assayed by adding mitogens to culture singly or conjointly indicated that LPS and Poly IC activate nearly identical B lymphocyte subpopulations, whereas PPD stimulates a subset of cells distinct from that which is responsive to the former two mitogens. The mitogen responsiveness of CBA/N mice, relative to normal CBA/WEHI mice, was shown to decrease as a function of the maturity of the subpopulation of lymphocytes activated. The CBA/N mouse was shown to be unresponsive to stimulation by 2-ME

  11. Survival and PHA-stimulation of #betta#-irradiated human peripheral blood T lymphocyte subpopulations

    International Nuclear Information System (INIS)

    Schwartz, J.L.; Darr, D.C.; Daulden, M.E.

    1983-01-01

    Human peripheral blood T lymphocyte subpopulations were identified and isolated on the basis of their ability to bind IgG (T-G), IgM (T-M), or neither immunoglobulin class (T-null). Lymphocytes were exposed to 0, 0.5, 1.0, 2.5 or 5.0 Gy of 60 Co #betta#-rays either as a T-cell suspension or as separated T cell subsets. Survival curves, determined 5 days after irradiation, revealed that each subset has radiosensitive and radioresistant portions, and that the T-G cell is the most sensitive subset. Mitotic indices of 48-h cultures showed that the response of unirradiated T lymphocytes to PHA varied greatly among the subsets, the highest indices being obtained for the T-M and the lowest for the T-G cells. With the possible exception of the T-G cells, the subsets are realtively resistant to mitotic effects of #betta#-rays. T-G cells suppress the PHA-induced mitotic response of the other T lymphocyte subsets, and this suppressor effect is radiosensitive, being abolished by 1.0 Gy. It is concluded that lymphocytes exposed to >= 1 Gy of #betta#-rays will have very few dividing B lymphocytes or T-G cells. This together with radiation-induced loss of T-G suppressor action means that the predominant lymphocyte types in mitosis after >=1 Gy are the radioresistant T-M and T-null cells. (orig.)

  12. Low in vitro response to PPD and PHA in lymphocytes from BCG-induced pleurisy in guinea pigs

    International Nuclear Information System (INIS)

    Widstroem, O.; Nilsson, B.S.

    1982-01-01

    In order to study any correlation between functional properties of lymphocytes in BCG-induced pleural exudation and the development of the pleurisy a previously described experimental model was used. This model with a duration of effusion of more than 17 days has characteristic stages. From the third day and onwards there are lymphocytes in sufficient amount for in vitro cultures. Proliferation of lymphocytes from the fluid was measured as uptake of 14 C-thymidine. The response of the lymphocytes to PPD tuberculin and to phytohemagglutinin (PHA) was studied, and their spontaneous activity was measured. Comparisons were made with lymphocytes from regional lymph nodes. Pleural lymphocytes sampled on the third post-induction day did not respond to PPD or PHA stimulation. In later stages, pleural lymphocytes were stimulated by PPD to approximately the same degree as the lymph node lymphocytes. The response to PHA was weak at all stages of pleurisy, though in later stages there were some cases with high values. Variations in activation ability, related to disease staging, were demonstrated. However, low activities, and variability of the responces, without concomitant variations in disease, speak against a connection between the course of disease and functional status of the lymphocytes as measured in this study. (authors)

  13. TH-C-12A-06: Feasibility of a MLC-Based Inversely Optimized Multi-Field Grid Therapy Technique

    Energy Technology Data Exchange (ETDEWEB)

    Jin, J [Georgia Regents University, Augusta, GA (Georgia); Zhao, B; Huang, Y; Kim, J; Qin, Y; Wen, N; Ryu, S; Chetty, I [Henry Ford Health System, Detroit, MI (United States)

    2014-06-15

    Purpose: Grid therapy (GT), which generates highly spatially modulated dose distributions, can deliver single- or hypo-fractionated radiotherapy for large tumors without causing significant toxicities. GT may be applied in combination with immunotherapy, in light of recent preclinical data of synergetic interaction between radiotherapy and immunotherapy. However, conventional GT uses only one field, which does not have the advantage of multi-fields in 3D conformal-RT or IMRT. We have proposed a novel MLC-based, inverse-planned multi-field 3D GT technique. This study aims to test its deliverability and dosimetric accuracy. Methods: A lattice of small spheres was created as the boost volume within a large target. A simultaneous boost IMRT plan with 8-Gy to the target and 20-Gy to the boost volume was generated in the Eclipse treatment planning system (AAA v10) with a HD120 MLC. Nine beams were used, and the gantry and couch angles were selected so that the spheres were perfectly aligned in every beams eye view. The plan was mapped to a phantom with dose scaled. EBT3 films were calibrated and used to measure the delivered dose. Results: The IMRT plan generated a highly spatially modulated dose distribution in the target. D95%, D50%, D5% for the spheres and the targets in Gy were 18.5, 20.0, 21.4 and 7.9, 9.8, 16.1, respectively. D50% for a 1cm ring 1cm outside the target was 2.9-Gy. Film dosimetry showed good agreement between calculated and delivered dose, with an overall gamma passing rate of 99.6% (3%/1mm). The point dose differences for different spheres varied from 1–6%. Conclusion: We have demonstrated the deliverability and dose calculation accuracy of the MLC-based inversely optimized multi-field GT technique, which achieved a brachytherapy-like dose distribution. Single-fraction high dose can be delivered to the spheres in a large target with minimal dose to the surrounding normal tissue.

  14. Refinement of MLC modeling improves commercial QA dosimetry system for SRS and SBRT patient-specific QA.

    Science.gov (United States)

    Hillman, Yair; Kim, Josh; Chetty, Indrin; Wen, Ning

    2018-04-01

    Mobius 3D (M3D) provides a volumetric dose verification of the treatment planning system's calculated dose using an independent beam model and a collapsed cone convolution superposition algorithm. However, there is a lack of investigation into M3D's accuracy and effectiveness for stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT) quality assurance (QA). Here, we collaborated with the vendor to develop a revised M3D beam model for SRS/SBRT cases treated with a 6X flattening filter-free (FFF) beam and high-definition multiple leaf collimator (HDMLC) on an Edge linear accelerator. Eighty SRS/SBRT cases, planned with AAA dose algorithm and validated with Gafchromic film, were compared to M3D dose calculations using 3D gamma analysis with 2%/2 mm gamma criteria and a 10% threshold. A revised beam model was developed by refining the HD-MLC model in M3D to improve small field dose calculation accuracy and beam profile agreement. All cases were reanalyzed using the revised beam model. The impact of heterogeneity corrections for lung cases was investigated by applying lung density overrides to five cases. For the standard and revised beam models, respectively, the mean gamma passing rates were 94.6% [standard deviation (SD): 6.1%] and 98.0% [SD: 1.7%] (for the overall patient), 88.2% [SD: 17.3%] and 93.8% [SD: 6.8%] (for the brain PTV), 71.4% [SD: 18.4%] and 81.5% [SD: 14.3%] (for the lung PTV), 83.3% [SD: 16.7%] and 67.9% [SD: 23.0%] (for the spine PTV), and 78.6% [SD: 14.0%] and 86.8% [SD: 12.5%] (for the PTV of all other sites). The lung PTV mean gamma passing rates improved from 74.1% [SD: 7.5%] to 89.3% [SD: 7.2%] with the lung density overridden. The revised beam model achieved an output factor within 3% of plastic scintillator measurements for 2 × 2 cm 2 MLC field size, but larger discrepancies are still seen for smaller field sizes which necessitate further improvement of the beam model. Special attention needs to be paid to small field

  15. Development of an iterative reconstruction method to overcome 2D detector low resolution limitations in MLC leaf position error detection for 3D dose verification in IMRT

    NARCIS (Netherlands)

    Visser, Ruurd; J., Godart; Wauben, D.J.L.; Langendijk, J.; van 't Veld, A.A.; Korevaar, E.W.

    2016-01-01

    The objective of this study was to introduce a new iterative method to reconstruct multi leaf collimator (MLC) positions based on low resolution ionization detector array measurements and to evaluate its error detection performance. The iterative reconstruction method consists of a fluence model, a

  16. Food allergens inducing a lymphocyte-mediated immunological reaction in canine atopic-like dermatitis.

    Science.gov (United States)

    Suto, Akemi; Suto, Yukinori; Onohara, Nozomi; Tomizawa, Yu; Yamamoto-Sugawara, Yukiko; Okayama, Taro; Masuda, Kenichi

    2015-02-01

    Canine atopic-like dermatitis (ALD) is suspected to be associated with food allergies, particularly those mediated by lymphocytes. In this study, 54 cases were included as ALD dogs, based on the negative IgE test results. In the dogs, the percentage of activated cells in helper-T lymphocytes was measured by flow cytometry using cultured peripheral lymphocytes under food allergen stimulation. We observed that 49 of the 54 ALD dogs (90.7%) had positive lymphocyte reactions against one or more food allergens. The most common food allergen was soybean, showing positive results in 21 dogs (42.9%), while the allergen to cause the lowest number of reactions was catfish (only 5 dogs, 10.2%). These results may be useful in considering elimination diets for ALD dogs.

  17. Potential of discrete Gaussian edge feathering method for improving abutment dosimetry in eMLC-delivered segmented-field electron conformal therapy

    Energy Technology Data Exchange (ETDEWEB)

    Eley, John G.; Hogstrom, Kenneth R.; Matthews, Kenneth L.; Parker, Brent C.; Price, Michael J. [Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, 202 Nicholson Hall, Tower Drive, Baton Rouge, Louisiana 70803-4001 (United States); Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, 202 Nicholson Hall, Tower Drive, Baton Rouge, Louisiana 70803-4001 (United States) and Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809-3482 (United States); Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, 202 Nicholson Hall, Tower Drive, Baton Rouge, Louisiana 70803-4001 (United States); Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, 202 Nicholson Hall, Tower Drive, Baton Rouge, Louisiana 70803-4001 (United States) and Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809-3482 (United States)

    2011-12-15

    Purpose: The purpose of this work was to investigate the potential of discrete Gaussian edge feathering of the higher energy electron fields for improving abutment dosimetry in the planning volume when using an electron multileaf collimator (eMLC) to deliver segmented-field electron conformal therapy (ECT). Methods: A discrete (five-step) Gaussian edge spread function was used to match dose penumbras of differing beam energies (6-20 MeV) at a specified depth in a water phantom. Software was developed to define the leaf eMLC positions of an eMLC that most closely fit each electron field shape. The effect of 1D edge feathering of the higher energy field on dose homogeneity was computed and measured for segmented-field ECT treatment plans for three 2D PTVs in a water phantom, i.e., depth from the water surface to the distal PTV surface varied as a function of the x-axis (parallel to leaf motion) and remained constant along the y-axis (perpendicular to leaf motion). Additionally, the effect of 2D edge feathering was computed and measured for one radially symmetric, 3D PTV in a water phantom, i.e., depth from the water surface to the distal PTV surface varied as a function of both axes. For the 3D PTV, the feathering scheme was evaluated for 0.1-1.0-cm leaf widths. Dose calculations were performed using the pencil beam dose algorithm in the Pinnacle{sup 3} treatment planning system. Dose verification measurements were made using a prototype eMLC (1-cm leaf width). Results: 1D discrete Gaussian edge feathering reduced the standard deviation of dose in the 2D PTVs by 34, 34, and 39%. In the 3D PTV, the broad leaf width (1 cm) of the eMLC hindered the 2D application of the feathering solution to the 3D PTV, and the standard deviation of dose increased by 10%. However, 2D discrete Gaussian edge feathering with simulated eMLC leaf widths of 0.1-0.5 cm reduced the standard deviation of dose in the 3D PTV by 33-28%, respectively. Conclusions: A five-step discrete Gaussian edge

  18. SU-F-T-629: Effect of Multi-Leaf Collimator (MLC) Width On Plan Quality of Single-Isocenter VMAT Intracranial Stereotactic Radiosurgery for Multiple Metastases

    International Nuclear Information System (INIS)

    Kraus, J; Thomas, E; Wu, X; Fiveash, J; Popple, R

    2016-01-01

    Purpose: Single-isocenter VMAT has been shown able to create high quality plans for complex intracranial multiple metastasis SRS cases. Linacs capable of the technique are typically outfitted with an MLC that consists of a combination of 5 mm and 10 mm leaves (standard) or 2.5 mm and 5 mm leaves (high-definition). In this study, we test the hypothesis that thinner collimator leaves are associated with improved plan quality. Methods: Ten multiple metastasis cases were identified and planned for VMAT SRS using a 10 MV flattening filter free beam. Plans were created for a standard (std) and a high-definition (HD) MLC. Published values for leaf transmission factor and dosimetric leaf gap were utilized. All other parameters were invariant. Conformity (plan and individual target), moderate isodose spill (V50%), and low isodose spill (mean brain dose) were selected for analysis. Results: Compared to standard MLC, HD-MLC improved overall plan conformity (median: Paddick CI-HD = 0.83, Paddick CI-std = 0.79; p = 0.004 and median: RTOG CI-HD =1.18, RTOG CI-std =1.24; p = 0.01 ), improved individual lesion conformity (median: Paddick CI-HD,i =0.77, Paddick CI-std,i =0.72; p < 0.001 and median: RTOG CI-HD,i = 1.28, RTOG CI-std,i =1.35; p < 0.001), improved moderate isodose spill (median: V50%-HD = 37.0 cc, V50%-std = 45.7 cc; p = 0.002), and improved low dose spill (median: dmean-HD = 2.90 Gy, dmean-std = 3.19 Gy; p = 0.002). Conclusion: For the single-isocenter VMAT SRS of multiple metastasis plans examined, use of HD-MLC modestly improved conformity, moderate isodose, and low isodose spill compared to standard MLC. However, in all cases we were able to generate clinically acceptable plans with the standard MLC. More work is need to further quantify the difference in cases with higher numbers of small targets and to better understand any potential clinical significance. This research was supported in part by Varian Medical Systems.

  19. SU-F-T-629: Effect of Multi-Leaf Collimator (MLC) Width On Plan Quality of Single-Isocenter VMAT Intracranial Stereotactic Radiosurgery for Multiple Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Kraus, J; Thomas, E; Wu, X; Fiveash, J; Popple, R [University Alabama Birmingham, Birmingham, AL (United States)

    2016-06-15

    Purpose: Single-isocenter VMAT has been shown able to create high quality plans for complex intracranial multiple metastasis SRS cases. Linacs capable of the technique are typically outfitted with an MLC that consists of a combination of 5 mm and 10 mm leaves (standard) or 2.5 mm and 5 mm leaves (high-definition). In this study, we test the hypothesis that thinner collimator leaves are associated with improved plan quality. Methods: Ten multiple metastasis cases were identified and planned for VMAT SRS using a 10 MV flattening filter free beam. Plans were created for a standard (std) and a high-definition (HD) MLC. Published values for leaf transmission factor and dosimetric leaf gap were utilized. All other parameters were invariant. Conformity (plan and individual target), moderate isodose spill (V50%), and low isodose spill (mean brain dose) were selected for analysis. Results: Compared to standard MLC, HD-MLC improved overall plan conformity (median: Paddick CI-HD = 0.83, Paddick CI-std = 0.79; p = 0.004 and median: RTOG CI-HD =1.18, RTOG CI-std =1.24; p = 0.01 ), improved individual lesion conformity (median: Paddick CI-HD,i =0.77, Paddick CI-std,i =0.72; p < 0.001 and median: RTOG CI-HD,i = 1.28, RTOG CI-std,i =1.35; p < 0.001), improved moderate isodose spill (median: V50%-HD = 37.0 cc, V50%-std = 45.7 cc; p = 0.002), and improved low dose spill (median: dmean-HD = 2.90 Gy, dmean-std = 3.19 Gy; p = 0.002). Conclusion: For the single-isocenter VMAT SRS of multiple metastasis plans examined, use of HD-MLC modestly improved conformity, moderate isodose, and low isodose spill compared to standard MLC. However, in all cases we were able to generate clinically acceptable plans with the standard MLC. More work is need to further quantify the difference in cases with higher numbers of small targets and to better understand any potential clinical significance. This research was supported in part by Varian Medical Systems.

  20. Dynamic-MLC leaf control utilizing on-flight intensity calculations: A robust method for real-time IMRT delivery over moving rigid targets

    International Nuclear Information System (INIS)

    McMahon, Ryan; Papiez, Lech; Rangaraj, Dharanipathy

    2007-01-01

    An algorithm is presented that allows for the control of multileaf collimation (MLC) leaves based entirely on real-time calculations of the intensity delivered over the target. The algorithm is capable of efficiently correcting generalized delivery errors without requiring the interruption of delivery (self-correcting trajectories), where a generalized delivery error represents anything that causes a discrepancy between the delivered and intended intensity profiles. The intensity actually delivered over the target is continually compared to its intended value. For each pair of leaves, these comparisons are used to guide the control of the following leaf and keep this discrepancy below a user-specified value. To demonstrate the basic principles of the algorithm, results of corrected delivery are shown for a leading leaf positional error during dynamic-MLC (DMLC) IMRT delivery over a rigid moving target. It is then shown that, with slight modifications, the algorithm can be used to track moving targets in real time. The primary results of this article indicate that the algorithm is capable of accurately delivering DMLC IMRT over a rigid moving target whose motion is (1) completely unknown prior to delivery and (2) not faster than the maximum MLC leaf velocity over extended periods of time. These capabilities are demonstrated for clinically derived intensity profiles and actual tumor motion data, including situations when the target moves in some instances faster than the maximum admissible MLC leaf velocity. The results show that using the algorithm while calculating the delivered intensity every 50 ms will provide a good level of accuracy when delivering IMRT over a rigid moving target translating along the direction of MLC leaf travel. When the maximum velocities of the MLC leaves and target were 4 and 4.2 cm/s, respectively, the resulting error in the two intensity profiles used was 0.1±3.1% and -0.5±2.8% relative to the maximum of the intensity profiles. For

  1. Opinion: Interactions of innate and adaptive lymphocytes

    Science.gov (United States)

    Gasteiger, Georg; Rudensky, Alexander Y.

    2015-01-01

    Innate lymphocytes, including natural killer (NK) cells and the recently discovered innate lymphoid cells (ILCs) have crucial roles during infection, tissue injury and inflammation. Innate signals regulate the activation and homeostasis of innate lymphocytes. Less well understood is the contribution of the adaptive immune system to the orchestration of innate lymphocyte responses. We review our current understanding of the interactions between adaptive and innate lymphocytes, and propose a model in which adaptive T cells function as antigen-specific sensors for the activation of innate lymphocytes to amplify and instruct local immune responses. We highlight the potential role of regulatory and helper T cells in these processes and discuss major questions in the emerging area of crosstalk between adaptive and innate lymphocytes. PMID:25132095

  2. The use of intensity-modulated radiation therapy photon beams for improving the dose uniformity of electron beams shaped with MLC.

    Science.gov (United States)

    Mosalaei, Homeira; Karnas, Scott; Shah, Sheel; Van Doodewaard, Sharon; Foster, Tim; Chen, Jeff

    2012-01-01

    Electrons are ideal for treating shallow tumors and sparing adjacent normal tissue. Conventionally, electron beams are collimated by cut-outs that are time-consuming to make and difficult to adapt to tumor shape throughout the course of treatment. We propose that electron cut-outs can be replaced using photon multileaf collimator (MLC). Two major problems of this approach are that the scattering of electrons causes penumbra widening because of a large air gap, and available commercial treatment planning systems (TPSs) do not support MLC-collimated electron beams. In this study, these difficulties were overcome by (1) modeling electron beams collimated by photon MLC for a commercial TPS, and (2) developing a technique to reduce electron beam penumbra by adding low-energy intensity-modulated radiation therapy (IMRT) photons (4 MV). We used blocks to simulate MLC shielding in the TPS. Inverse planning was used to optimize boost photon beams. This technique was applied to a parotid and a central nervous system (CNS) clinical case. Combined photon and electron plans were compared with conventional plans and verified using ion chamber, film, and a 2D diode array. Our studies showed that the beam penumbra for mixed beams with 90 cm source to surface distance (SSD) is comparable with electron applicators and cut-outs at 100 cm SSD. Our mixed-beam technique yielded more uniform dose to the planning target volume and lower doses to various organs at risk for both parotid and CNS clinical cases. The plans were verified with measurements, with more than 95% points passing the gamma criteria of 5% in dose difference and 5 mm for distance to agreement. In conclusion, the study has demonstrated the feasibility and potential advantage of using photon MLC to collimate electron beams with boost photon IMRT fields. Copyright © 2012 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  3. SU-E-J-109: Testing the KV Imaging Center Congruence with Radiation Isocenter of Small MLC and SRS Cone Field On Two Machines

    Energy Technology Data Exchange (ETDEWEB)

    Fu,; Chen, Y; Yu, Y; Liu, H [Thomas Jefferson University, Philadelphia, PA (United States)

    2014-06-01

    Purpose: Orthogonal kV image pairs are used for target localization when fiducial markers are implanted. CBCT is used to verify cone SRS setup. Therefore it is necessary to evaluate the isocenter congruence between radiation fields and kV imaging center. This study used a simple method to evaluate the isocenter congruence, and compared the results for MLC and cone fields on two different Linacs. Methods: Varian OBI block was attached on the couch. It has a central 1mm BB with markers on three surfaces to align with laser. KV and MV images were taken at four cardinal angles. A 3x3cm2 MLC field and a 20mm cone field were irradiated respectively. On each kV image, the distance from BB center to the kV graticule center were measured. On the MV image of MLC field, the center of radiation field was determined manually, while for cone field, the Varian AM maintenance software was used to analyze the distance between BB and radiation field. The subtraction of the two distances gives the discrepancy between kV and radiation centers. Each procedure was repeated on five days at Trilogy and TrueBeam respectively. Results: The maximum discrepancy was found in the longitudinal direction at 180° gantry angel. It was 1.5±0.1mm for Trilogy and 0.6±0.1mm for TrueBeam. For Trilogy, although radiation center wobbled only 0.7mm and image center wobbled 0.8mm, they wobbled to the opposite direction. KV Pair using gantry 180° should be avoided in this case. Cone vs. kV isocenter has less discrepancy than MLC for Trilogy. Conclusion: Radiation isocenter of MLC and cone field is different, so is between Trilogy and TrueBeam. The method is simple and reproducible to check kV and radiation isocenter congruence.

  4. SU-E-J-109: Testing the KV Imaging Center Congruence with Radiation Isocenter of Small MLC and SRS Cone Field On Two Machines

    International Nuclear Information System (INIS)

    Fu,; Chen, Y; Yu, Y; Liu, H

    2014-01-01

    Purpose: Orthogonal kV image pairs are used for target localization when fiducial markers are implanted. CBCT is used to verify cone SRS setup. Therefore it is necessary to evaluate the isocenter congruence between radiation fields and kV imaging center. This study used a simple method to evaluate the isocenter congruence, and compared the results for MLC and cone fields on two different Linacs. Methods: Varian OBI block was attached on the couch. It has a central 1mm BB with markers on three surfaces to align with laser. KV and MV images were taken at four cardinal angles. A 3x3cm2 MLC field and a 20mm cone field were irradiated respectively. On each kV image, the distance from BB center to the kV graticule center were measured. On the MV image of MLC field, the center of radiation field was determined manually, while for cone field, the Varian AM maintenance software was used to analyze the distance between BB and radiation field. The subtraction of the two distances gives the discrepancy between kV and radiation centers. Each procedure was repeated on five days at Trilogy and TrueBeam respectively. Results: The maximum discrepancy was found in the longitudinal direction at 180° gantry angel. It was 1.5±0.1mm for Trilogy and 0.6±0.1mm for TrueBeam. For Trilogy, although radiation center wobbled only 0.7mm and image center wobbled 0.8mm, they wobbled to the opposite direction. KV Pair using gantry 180° should be avoided in this case. Cone vs. kV isocenter has less discrepancy than MLC for Trilogy. Conclusion: Radiation isocenter of MLC and cone field is different, so is between Trilogy and TrueBeam. The method is simple and reproducible to check kV and radiation isocenter congruence

  5. Damage of lymphocytes by ionizing irradiation

    International Nuclear Information System (INIS)

    Rose, H.; Moldenhauer, H.; Kehrberg, G.

    1985-01-01

    After a short review, how lymphocytes of the peripheral blood are influenced by radiotherapy, the damage of lymphocytes by whole-body irradiation is pointed out in animal experiments and after in vitro irradiation. The special sensibility of B-cells and their homogeneity in fields of radiobiology are opposed to the heterogeneity of T-cells. The radiosensibility of cytotoxic lymphocytes, suppressor cells, and helper cells are discussed. It appears, that within these functional criteria, there is a different radiosensibility, too. (author)

  6. TH-AB-BRB-05: Using a Research Real-Time Control Interface to Go Beyond Dynamic MLC Tracking

    Energy Technology Data Exchange (ETDEWEB)

    Nill, S. [The Institute of Cancer Research (United Kingdom)

    2016-06-15

    Current state-of-the art digital C-arm medical linear accelerators are capable of delivering radiation treatments with high level of automation, which affords coordinated motions of gantry, couch, and multileaf collimator (MLC) with dose rate modulations. The new machine capacity has shown the potential to bring substantially improved radiation dosimetry and/or delivery efficiency to many challenging diseases. Combining an integrated beam orientation optimization algorithm with automated machine navigation, markedly improved dose conformity has been achieved using 4ρ therapy. Trajectory modulated radiation therapy (TMAT) can be used to deliver highly conformal dose to partial breast or to carve complex dose distribution for therapy involving extended volumes such as total marrow and total lymph node treatment. Dynamic electron arc radiotherapy (DEAR) not only overcomes the deficiencies of conventional electron therapy in dose conformity and homogeneity but also achieves so without patient-specific shields. The combination of MLC and couch tracking provides improved motion management of thoracic and abdominal tumors. A substantial body of work has been done in these technological advances for clinical translation. The proposed symposium will provide a timely review of these exciting opportunities. Learning Objectives: Recognize the potential of using digitally controlled linacs for clinically significant improvements in delivered dose distributions for various treatment sites. Identify existing approaches to treatment planning, optimization and delivery for treatment techniques utilizing the advanced functions of digital linacs and venues for further development and improvement. Understand methods for testing and validating delivery system performance. Identify tools available on current delivery systems for implementation and control for such treatments. Obtain the update in clinical applications, trials and regulatory approval. K. Sheng, NIH U19AI067769, NIH R43

  7. TH-AB-BRB-05: Using a Research Real-Time Control Interface to Go Beyond Dynamic MLC Tracking

    International Nuclear Information System (INIS)

    Nill, S.

    2016-01-01

    Current state-of-the art digital C-arm medical linear accelerators are capable of delivering radiation treatments with high level of automation, which affords coordinated motions of gantry, couch, and multileaf collimator (MLC) with dose rate modulations. The new machine capacity has shown the potential to bring substantially improved radiation dosimetry and/or delivery efficiency to many challenging diseases. Combining an integrated beam orientation optimization algorithm with automated machine navigation, markedly improved dose conformity has been achieved using 4ρ therapy. Trajectory modulated radiation therapy (TMAT) can be used to deliver highly conformal dose to partial breast or to carve complex dose distribution for therapy involving extended volumes such as total marrow and total lymph node treatment. Dynamic electron arc radiotherapy (DEAR) not only overcomes the deficiencies of conventional electron therapy in dose conformity and homogeneity but also achieves so without patient-specific shields. The combination of MLC and couch tracking provides improved motion management of thoracic and abdominal tumors. A substantial body of work has been done in these technological advances for clinical translation. The proposed symposium will provide a timely review of these exciting opportunities. Learning Objectives: Recognize the potential of using digitally controlled linacs for clinically significant improvements in delivered dose distributions for various treatment sites. Identify existing approaches to treatment planning, optimization and delivery for treatment techniques utilizing the advanced functions of digital linacs and venues for further development and improvement. Understand methods for testing and validating delivery system performance. Identify tools available on current delivery systems for implementation and control for such treatments. Obtain the update in clinical applications, trials and regulatory approval. K. Sheng, NIH U19AI067769, NIH R43

  8. Radiation sensitivity of human malignant lymphocytes

    International Nuclear Information System (INIS)

    Seshadri, R.; Matthews, C.; Morley, A.A.

    1985-01-01

    A simple and rapid in vitro technique to assess the sensitivity of human malignant lymphocytes to roentgen irradiation is described. A variety of established malignant lymphocyte cell lines were cloned in microwells and clone survival was used as the end-point. The survival of the clonogenic malignant lymphocyte down to a fraction of approximately 0.001 could be measured accurately. Except for a T-cell line, the radiation sensitivities of the cell lines were similar to that of normal T-lymphocytes. (orig.)

  9. Autoimmune hepatitis in association with lymphocytic colitis.

    LENUS (Irish Health Repository)

    Cronin, Edmond M

    2012-02-03

    Autoimmune hepatitis is a rare, chronic inflammatory disorder which has been associated with a number of other auto-immune conditions. However, there are no reports in the medical literature of an association with microscopic (lymphocytic) colitis. We report the case of a 53-year-old woman with several autoimmune conditions, including lymphocytic colitis, who presented with an acute hepatitis. On the basis of the clinical features, serology, and histopathology, we diagnosed autoimmune hepatitis. To our knowledge, this is the first report of autoimmune hepatitis in association with lymphocytic colitis, and lends support to the theory of an autoimmune etiology for lymphocytic colitis.

  10. Lymphocytes on sounding rocket flights.

    Science.gov (United States)

    Cogoli-Greuter, M; Pippia, P; Sciola, L; Cogoli, A

    1994-05-01

    Cell-cell interactions and the formation of cell aggregates are important events in the mitogen-induced lymphocyte activation. The fact that the formation of cell aggregates is only slightly reduced in microgravity suggests that cells are moving and interacting also in space, but direct evidence was still lacking. Here we report on two experiments carried out on a flight of the sounding rocket MAXUS 1B, launched in November 1992 from the base of Esrange in Sweden. The rocket reached the altitude of 716 km and provided 12.5 min of microgravity conditions.

  11. Chromosome aberrations frequencies in peripheral blood lymphocytes from patients with larynx cancer

    International Nuclear Information System (INIS)

    Lisowska, H.; Lankoff, A.; Banasik, A.; Padjas, A.; Wieczorek, A.; Kuszewski, T.; Gozdz, A.; Wojcik, A.

    2005-01-01

    There is data suggesting that the sensitivity to ionising radiation of peripheral blood lymphocytes of cancer patients is higher than in healthy donors. This effect is especially prominent when chromosomal aberrations induced in S/G2 phase of the cell cycle are analysed. The aim of our study was to investigate if the S/G2- aberration frequencies in lymphocytes of patients with larynx cancer were higher than in control individuals. In addition, the multiple fixation regimen was applied in lymphocytes of the cancer patients. The aim of this was to check if the aberration frequencies scored in cells harvested at one time point were representative for a larger fraction of the cell cycle. Peripheral blood of 40 patients was collected before the onset of radiotherapy, cultured and irradiated with Co-60 (2 Gy) after 67 hours of culture time. Irradiation was performed in the Swietokrzyskie Oncology Center. Chromosome specimens were prepared from cells fixed at three time points after irradiation: 5, 7 and 9 hours. Colcemide was always added for 2 hours before harvest. Lymphocytes of 40 healthy donors were cultured and irradiated in the same way like in the case of patients with cancer, however, they were only harvested at one time point (5 hours p.r.). No statistically significant differences in aberration frequencies were observed between lymphocytes harvested at the 3 time points. In both donor groups, individual differences in aberration frequencies were observed. Despite this, the aberration frequencies in lymphocytes of patients were in average higher than in the healthy donors. This suggests, that the radiation sensitivity of lymphocytes of patients with larynx cancer may be a marker of cancer predisposition. More patients must be analysed to confirm this hypothesis. (author)

  12. Cytogenetic determination of the effect of irradiation on in vitro lymphocyte transformation rates

    International Nuclear Information System (INIS)

    Lloyd, D.C.; Dolphin, G.W.; Purrott, R.J.

    1976-01-01

    The effect of x irradiation on the yield of transformed cells in 48-hr cultures has been studied in human peripheral-blood lymphocytes. Cytogenetic damage was used as a marker, aberration yields being obtained for mixed cultures prepared from equal numbers of normal and irradiated lymphocytes and from pure cultures of irradiated cells. Comparison of data from these two types of culture shows that the yield observed ranged from 90 percent of that expected at 50 rads to 11 percent at 700 rads. Poisson analysis demonstrated that for all doses, cells with high levels of structural damage were not selectively eliminated. The extent to which mitotic delay contributes to the reduction in numbers of transformed cells was examined by varying the time in cultures from 36 to 72 hr. The implication of this work in the field of radiation-dose estimation by chromosome-aberration analysis is discussed

  13. Fish Lymphocytes: An Evolutionary Equivalent of Mammalian Innate-Like Lymphocytes?

    Directory of Open Access Journals (Sweden)

    Giuseppe Scapigliati

    2018-05-01

    Full Text Available Lymphocytes are the responsible of adaptive responses, as they are classically described, but evidence shows that subpopulations of mammalian lymphocytes may behave as innate-like cells, engaging non-self rapidly and without antigen presentation. The innate-like lymphocytes of mammals have been mainly identified as γδT cells and B1-B cells, exert their activities principally in mucosal tissues, may be involved in human pathologies and their functions and tissue(s of origin are not fully understood. Due to similarities in the morphology and immunobiology of immune system between fish and mammals, and to the uniqueness of having free-living larval stages where the development can be precisely monitored and engineered, teleost fish are proposed as an experimental model to investigate human immunity. However, the homology between fish lymphocytes and mammalian innate-like lymphocytes is an issue poorly considered in comparative immunology. Increasing experimental evidence suggests that fish lymphocytes could have developmental, morphological, and functional features in common with innate-like lymphocytes of mammals. Despite such similarities, information on possible links between conventional fish lymphocytes and mammalian innate-like lymphocytes is missing. The aim of this review is to summarize and describe available findings about the similarities between fish lymphocytes and mammalian innate-like lymphocytes, supporting the hypothesis that mammalian γδT cells and B1-B cells could be evolutionarily related to fish lymphocytes.

  14. Discrimination of human cytotoxic lymphocytes from regulatory and B-lymphocytes by orthogonal light scattering

    NARCIS (Netherlands)

    Terstappen, Leonardus Wendelinus Mathias Marie; de Grooth, B.G.; ten Napel, C.H.H.; van Berkel, W.; Greve, Jan

    1986-01-01

    Light scattering properties of human lymphocyte subpopulations selected by immunofluorescence were studied with a flow cytometer. Regulatory and B-lymphocytes showed a low orthogonal light scatter signal, whereas cytotoxic lymphocytes identified with leu-7, leu-11 and leu-15 revealed a large

  15. Detection of adult T-cell leukemia virus (ATLV) bearing lymphocytes in concentrated red blood cells derived from ATL associated antibody (ATLA-Ab) positive donors.

    Science.gov (United States)

    Morishima, Y; Ohya, K; Ueda, R; Fukuda, T

    1986-01-01

    Adult T cell leukemia associated antibody (ATLA-Ab) positive persons were screened by indirect immunofluorescence (IF) testing. Their lymphocytes were collected from concentrated red blood cells (CRC), and cultured in vitro with and without phytohemagglutinin (PHA) for 10 days. The expression of ATL virus (ATLV) positive lymphocytes during the in vitro culture was then analyzed by IF assay using mouse monoclonal antibody ATL-19 reactive to p19 core protein of ATLV. 97% of ATLA-Ab positive CRC (36 cases) demonstrated ATLV positive lymphocytes after being cultured for more than 10 days with PHA, whereas, none of ATLA-Ab negative CRC (22 cases) demonstrated ATLV positive lymphocytes. All of the 10 ATLA-Ab positive CRC that were stored for 2, 4, and 7 days contained lymphocytes which expressed ATLV after in vitro culture, while 7 of 10 CRC stored for 14 days and only 1 of 10 CRCs stored for 20 days, expressed ATLV positive lymphocytes. This data indicates that almost all of the ATLA-Ab positive blood contained ATLV positive lymphocytes, and that the in vitro appearance of these ATLV positive lymphocytes was reduced by storing the CRC for more than 14 days.

  16. Vincristine-induced bystander effect in human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Testi, Serena; Azzarà, Alessia; Giovannini, Caterina; Lombardi, Sara [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Piaggi, Simona [Dipartimento di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, Pisa University, Via Savi 10, 56126 Pisa (Italy); Facioni, Maria Sole [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Scarpato, Roberto, E-mail: roberto.scarpato@unipi.it [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Research Center of Nutraceuticals and Food for Health, University of Pisa, Pisa (Italy)

    2016-07-15

    Highlights: • We studied whether or not vincristine induced a bystander response in human lymphocytes. • Vincristine significantly increased MN frequencies in mononucleated recipient cells. • ROS or soluble proteins (IL-32 and TGF-β) may account for the observed response. - Abstract: Bystander effect is a known radiobiological effect, widely described using ionizing radiations and which, more recently, has also been related to chemical mutagens. In this study, we aimed to assess whether or not a bystander response can be induced in cultured human peripheral lymphocytes by vincristine, a chemotherapeutic mutagen acting as spindle poison, and by mitomycin-C, an alkylating agent already known to induce this response in human lymphoblastoid cells. Designing a modified ad hoc protocol for the cytokinesis blocked micronucleus (MN) assay, we detected the presence of a dose-dependent bystander response in untreated cultures receiving the conditioned medium (CM) from mitomycin-C (MMC) or vincristine (VCR) treated cultures. In the case of MMC, MN frequencies, expressed as micronucleated binucleates, were: 13.5 ± 1.41 at 6 μM, 22 ± 2.12 at 12 μM or 28.25 ± 5.13 at 15 μM vs. a control value of 4.75 ± 1.59. MN levels for VCR, expressed as micronucleated mononucleates were: 2.75 ± 0.88 at 0.0 μM, 27.25 ± 2.30 at 0.4 μM, 46.25 ± 1.94 at 0.8 μM, 98.25 ± 7.25 at 1.6 μM. To verify that no mutagen residual was transferred to recipient cultures together with the CM, we evaluated MN levels in cultures receiving the medium immediately after three washings following the chemical treatment (unconditioned medium). We further confirmed these results using a cell-mixing approach where untreated lymphocytes were co-cultured with donor cells treated with an effect-inducing dose of MMC or VCR. A distinct production pattern of both reactive oxygen species and soluble mediator proteins by treated cells may account for the differences observed in the manifestation of the

  17. Vincristine-induced bystander effect in human lymphocytes

    International Nuclear Information System (INIS)

    Testi, Serena; Azzarà, Alessia; Giovannini, Caterina; Lombardi, Sara; Piaggi, Simona; Facioni, Maria Sole; Scarpato, Roberto

    2016-01-01

    Highlights: • We studied whether or not vincristine induced a bystander response in human lymphocytes. • Vincristine significantly increased MN frequencies in mononucleated recipient cells. • ROS or soluble proteins (IL-32 and TGF-β) may account for the observed response. - Abstract: Bystander effect is a known radiobiological effect, widely described using ionizing radiations and which, more recently, has also been related to chemical mutagens. In this study, we aimed to assess whether or not a bystander response can be induced in cultured human peripheral lymphocytes by vincristine, a chemotherapeutic mutagen acting as spindle poison, and by mitomycin-C, an alkylating agent already known to induce this response in human lymphoblastoid cells. Designing a modified ad hoc protocol for the cytokinesis blocked micronucleus (MN) assay, we detected the presence of a dose-dependent bystander response in untreated cultures receiving the conditioned medium (CM) from mitomycin-C (MMC) or vincristine (VCR) treated cultures. In the case of MMC, MN frequencies, expressed as micronucleated binucleates, were: 13.5 ± 1.41 at 6 μM, 22 ± 2.12 at 12 μM or 28.25 ± 5.13 at 15 μM vs. a control value of 4.75 ± 1.59. MN levels for VCR, expressed as micronucleated mononucleates were: 2.75 ± 0.88 at 0.0 μM, 27.25 ± 2.30 at 0.4 μM, 46.25 ± 1.94 at 0.8 μM, 98.25 ± 7.25 at 1.6 μM. To verify that no mutagen residual was transferred to recipient cultures together with the CM, we evaluated MN levels in cultures receiving the medium immediately after three washings following the chemical treatment (unconditioned medium). We further confirmed these results using a cell-mixing approach where untreated lymphocytes were co-cultured with donor cells treated with an effect-inducing dose of MMC or VCR. A distinct production pattern of both reactive oxygen species and soluble mediator proteins by treated cells may account for the differences observed in the manifestation of the

  18. Canine lymphocyte activating factor (LAF)

    International Nuclear Information System (INIS)

    Shifrine, M.; Whaley, C.B.; Wilson, F.D.; Taylor, N.J.

    1979-01-01

    The immune response of an animal is the sum of the result of the interaction of various cells mainly through soluble mediators. It is not enough to look at specific cell populations, it is also necessary to study the interactions between purified cell population. The effect of one subpopulation on another is via soluble mediators. We have been studying one (of several) such mediators in its relation to radiation effects on the immune response. Lymphocyte activating factor (LAF) is defined functionally as a potentiator of the response of thymocytes to phytohemagglutinin (PHA) or concanavalin (con-A). It can also elicit response of unstimulated subpopulations separated from the thymus. It is a product of adherent populations, presumably macrophages. It has been shown to be produced by human, rabbit, and mouse cells, but has not been reported in the dog. It also was shown to be present in higher concentrations in irradiated mice than in comparable unirradiated mice. We have shown that LAF is produced by plastic-adherent populations derived from peripheral blood. Currently we are working to determine the lymphocyte subpopulations with which LAF interacts

  19. Lymphocytic infiltration of bladder after local cellular immunotherapy.

    Science.gov (United States)

    Ingram, M; Bishai, M B; Techy, G B; Narayan, K S; Saroufeem, R; Yazan, O; Marshall, C E

    2000-01-01

    This is a case report of a patient who received cellular immunotherapy, in the form of local injections of autologous stimulated lymphocytes (ASL) into individual tumors in the urinary bladder. A major consideration in cellular immunotherapy being the ability of immune cells to reach all target areas, we hypothesized that direct delivery of effector cells into individual bladder tumors might assure such access. ASL were generated by exposing the patient's PBL to phytohemagglutinin and culturing them in the presence of IL-2 to expand the population. ASL were injected into the base of individual bladder tumors three times at intervals of 3 weeks. The patient died of a myocardial infarct, unrelated to cell therapy, 20 days after the third injection. An autopsy was performed. Histological sections of the bladder showed extensive lymphocytic infiltration of virtually the entire organ. No conclusions about the therapeutic efficacy of local immunotherapy using ASL are possible. Nevertheless, the observations reported, taken together with reports of therapeutic efficacy of other immunotherapy regimens in the management of bladder cancer, suggest that ready access of stimulated lymphocytes to all regions of the organ may account, in part, for the relatively high rate of therapeutic success reported for various immunotherapy regimens for this malignancy.

  20. The Danish National Chronic Lymphocytic Leukemia Registry

    DEFF Research Database (Denmark)

    da Cunha-Bang, Caspar; Geisler, Christian Hartmann; Enggaard, Lisbeth

    2016-01-01

    AIM: In 2008, the Danish National Chronic Lymphocytic Leukemia Registry was founded within the Danish National Hematology Database. The primary aim of the registry is to assure quality of diagnosis and care of patients with chronic lymphocytic leukemia (CLL) in Denmark. Secondarily, to evaluate...

  1. Lymphocyte-platelet crosstalk in Graves' disease.

    Science.gov (United States)

    Kuznik, Boris I; Vitkovsky, Yuri A; Gvozdeva, Olga V; Solpov, Alexey V; Magen, Eli

    2014-03-01

    Platelets can modulate lymphocytes' role in the pathophysiology of thyroid autoimmune diseases. The present study was performed to clarify the status of platelet-lymphocyte subpopulations aggregation in circulating blood in patients with Graves' disease (GD). One hundred and fifty patients with GD (GD group) and 45 hyperthyroid patients with toxic multinodular goiter (TMG group) were recruited in the study. Control group consisted 150 healthy subjects. Immunophenotyping of lymphocytes was performed by flow cytometry. Detection of lymphocyte-platelet aggregates (LPAs) was done using light microscope after Ficoll-gradient centrifugation. The group of GD patients exhibited reduced CD8 lymphocyte and higher CD19 cell counts compared with TMG group and healthy controls. A greater number of activated CD3, HLA-DR+ lymphocytes were observed in GD than in TMG group and control group. GD group was characterized by lower blood platelet count (232 ± 89 × 10 cells/µL) than TMG group (251 ± 97 × 10 cells/µL; P TMG group (116 ± 67/µL, P < 0.005) and control group (104 ± 58 /µL; P < 0.001). GD is associated with higher levels of activated lymphocytes and lymphocyte-platelet aggregates.

  2. Clonal dominance among T-lymphocyte infiltrates in arthritis

    International Nuclear Information System (INIS)

    Stamenkovic, I.; Stegagno, M.; Wright, K.A.; Krane, S.M.; Amento, E.P.; Colvin, R.B.; Duquesnoy, R.J.; Kurnick, J.T.

    1988-01-01

    Synovial membranes in patients with rheumatoid arthritis as well as other types of chronic destructive inflammatory arthritis contain infiltrates of activated T lymphocytes that probably contribute to the pathogenesis of the disease. In an effort to elucidate the nature of these infiltrates, interleukin 2 (IL-2)-responsive T lymphocytes were grown out of synovial fragments from 14 patients undergoing surgery for advanced destructive inflammatory joint disease. Eleven of the samples examined were from patients with classical rheumatoid arthritis, while three others were obtained from individuals with clinical osteoarthritis. Southern blot analysis of T-cell receptor (TCR) β-chain genes in 13 of 14 cultures showed distinct rearrangements, indicating that each culture was characterized by the predominance of a limited number of clones. T-cell populations from peripheral blood stimulated with a variety of activators and expanded with IL-2 did not demonstrate evidence of similar clonality in long-term culture. These results suggest that a limited number of activated T-cell clones predominate at the site of tissue injury in rheumatoid synovial membranes as well as in other types of destructive inflammatory joint disease. Further characterization of these T-cell clones may aid our understanding of the pathogenesis of these rheumatic disorders

  3. TU-AB-BRC-04: Commissioning of a New MLC Model for the GEPTS Monte Carlo System: A Model Based On the Leaf and Interleaf Effective Density

    Energy Technology Data Exchange (ETDEWEB)

    Chibani, O; Tahanout, F; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2016-06-15

    Purpose: To commission a new MLC model for the GEPTS Monte Carlo system. The model is based on the concept of leaves and interleaves effective densities Methods: GEPTS is a Monte Carlo system to be used for external beam planning verification. GEPTS incorporates detailed photon and electron transport algorithms (Med.Phys. 29, 2002, 835). A new GEPTS model for the Varian Millennium MLC is presented. The model accounts for: 1) thick (1 cm) and thin (0.5 cm) leaves, 2) tongue-and-groove design, 3) High-Transmission (HT) and Low-Transmission (LT) interleaves, and 4) rounded leaf end. Leaf (and interleaf) height is set equal to 6 cm. Instead of modeling air gaps, screw holes, and complex leaf heads, “effective densities” are assigned to: 1) thin leaves, 2) thick leaves, 3) HT-, and 4) LT-interleaves. Results: The new MLC model is used to calculate dose profiles for Closed-MLC and Tongue-and-Groove fields at 5 cm depth for 6, 10 and 15 MV Varian beams. Calculations are compared with 1) Pin-point ionization chamber transmission ratios and 2) EBT3 Radiochromic films. Pinpoint readings were acquired beneath thick and thin leaves, and HT and LT interleaves. The best fit of measured dose profiles was obtained for the following parameters: Thick-leaf density = 16.1 g/cc, Thin-leaf density = 17.2 g/cc; HT Interleaf density = 12.4 g/cc, LT Interleaf density = 14.3 g/cc; Interleaf thickness = 1.1 mm. Attached figures show comparison of calculated and measured transmission ratios for the 3 energies. Note this is the only study where transmission profiles are compared with measurements for 3 different energies. Conclusion: The new MLC model reproduces transmission measurements within 0.1%. The next step is to implement the MLC model for real plans and quantify the improvement in dose calculation accuracy gained using this model for IMRT plans with high modulation factors.

  4. SU-G-BRB-03: Assessing the Sensitivity and False Positive Rate of the Integrated Quality Monitor (IQM) Large Area Ion Chamber to MLC Positioning Errors

    Energy Technology Data Exchange (ETDEWEB)

    Boehnke, E McKenzie; DeMarco, J; Steers, J; Fraass, B [Cedars-Sinai Medical Center, Los Angeles, CA (United States)

    2016-06-15

    Purpose: To examine both the IQM’s sensitivity and false positive rate to varying MLC errors. By balancing these two characteristics, an optimal tolerance value can be derived. Methods: An un-modified SBRT Liver IMRT plan containing 7 fields was randomly selected as a representative clinical case. The active MLC positions for all fields were perturbed randomly from a square distribution of varying width (±1mm to ±5mm). These unmodified and modified plans were measured multiple times each by the IQM (a large area ion chamber mounted to a TrueBeam linac head). Measurements were analyzed relative to the initial, unmodified measurement. IQM readings are analyzed as a function of control points. In order to examine sensitivity to errors along a field’s delivery, each measured field was divided into 5 groups of control points, and the maximum error in each group was recorded. Since the plans have known errors, we compared how well the IQM is able to differentiate between unmodified and error plans. ROC curves and logistic regression were used to analyze this, independent of thresholds. Results: A likelihood-ratio Chi-square test showed that the IQM could significantly predict whether a plan had MLC errors, with the exception of the beginning and ending control points. Upon further examination, we determined there was ramp-up occurring at the beginning of delivery. Once the linac AFC was tuned, the subsequent measurements (relative to a new baseline) showed significant (p <0.005) abilities to predict MLC errors. Using the area under the curve, we show the IQM’s ability to detect errors increases with increasing MLC error (Spearman’s Rho=0.8056, p<0.0001). The optimal IQM count thresholds from the ROC curves are ±3%, ±2%, and ±7% for the beginning, middle 3, and end segments, respectively. Conclusion: The IQM has proven to be able to detect not only MLC errors, but also differences in beam tuning (ramp-up). Partially supported by the Susan Scott Foundation.

  5. TH-AB-202-05: BEST IN PHYSICS (JOINT IMAGING-THERAPY): First Online Ultrasound-Guided MLC Tracking for Real-Time Motion Compensation in Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ipsen, S; Bruder, R; Schweikard, A [University of Luebeck, Luebeck, DE (United States); O’Brien, R; Keall, P [University of Sydney, Sydney (Australia); Poulsen, P [Aarhus University Hospital, Aarhus (Denmark)

    2016-06-15

    Purpose: While MLC tracking has been successfully used for motion compensation of moving targets, current real-time target localization methods rely on correlation models with x-ray imaging or implanted electromagnetic transponders rather than direct target visualization. In contrast, ultrasound imaging yields volumetric data in real-time (4D) without ionizing radiation. We report the first results of online 4D ultrasound-guided MLC tracking in a phantom. Methods: A real-time tracking framework was installed on a 4D ultrasound station (Vivid7 dimension, GE) and used to detect a 2mm spherical lead marker inside a water tank. The volumetric frame rate was 21.3Hz (47ms). The marker was rigidly attached to a motion stage programmed to reproduce nine tumor trajectories (five prostate, four lung). The 3D marker position from ultrasound was used for real-time MLC aperture adaption. The tracking system latency was measured and compensated by prediction for lung trajectories. To measure geometric accuracy, anterior and lateral conformal fields with 10cm circular aperture were delivered for each trajectory. The tracking error was measured as the difference between marker position and MLC aperture in continuous portal imaging. For dosimetric evaluation, 358° VMAT fields were delivered to a biplanar diode array dosimeter using the same trajectories. Dose measurements with and without MLC tracking were compared to a static reference dose using a 3%/3 mm γ-test. Results: The tracking system latency was 170ms. The mean root-mean-square tracking error was 1.01mm (0.75mm prostate, 1.33mm lung). Tracking reduced the mean γ-failure rate from 13.9% to 4.6% for prostate and from 21.8% to 0.6% for lung with high-modulation VMAT plans and from 5% (prostate) and 18% (lung) to 0% with low modulation. Conclusion: Real-time ultrasound tracking was successfully integrated with MLC tracking for the first time and showed similar accuracy and latency as other methods while holding the

  6. SU-E-P-21: Impact of MLC Position Errors On Simultaneous Integrated Boost Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Chengqiang, L; Yin, Y; Chen, L [Shandong Cancer Hospital and Institute, 440 Jiyan Road, Jinan, 250117 (China)

    2015-06-15

    Purpose: To investigate the impact of MLC position errors on simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) for patients with nasopharyngeal carcinoma. Methods: To compare the dosimetric differences between the simulated plans and the clinical plans, ten patients with locally advanced NPC treated with SIB-IMRT were enrolled in this study. All plans were calculated with an inverse planning system (Pinnacle3, Philips Medical System{sub )}. Random errors −2mm to 2mm{sub )},shift errors{sub (} 2mm,1mm and 0.5mm) and systematic extension/ contraction errors (±2mm, ±1mm and ±0.5mm) of the MLC leaf position were introduced respectively into the original plans to create the simulated plans. Dosimetry factors were compared between the original and the simulated plans. Results: The dosimetric impact of the random and system shift errors of MLC position was insignificant within 2mm, the maximum changes in D95% of PGTV,PTV1,PTV2 were-0.92±0.51%,1.00±0.24% and 0.62±0.17%, the maximum changes in the D0.1cc of spinal cord and brainstem were 1.90±2.80% and −1.78±1.42%, the maximum changes in the Dmean of parotids were1.36±1.23% and −2.25±2.04%.However,the impact of MLC extension or contraction errors was found significant. For 2mm leaf extension errors, the average changes in D95% of PGTV,PTV1,PTV2 were 4.31±0.67%,4.29±0.65% and 4.79±0.82%, the averaged value of the D0.1cc to spinal cord and brainstem were increased by 7.39±5.25% and 6.32±2.28%,the averaged value of the mean dose to left and right parotid were increased by 12.75±2.02%,13.39±2.17% respectively. Conclusion: The dosimetric effect was insignificant for random MLC leaf position errors up to 2mm. There was a high sensitivity to dose distribution for MLC extension or contraction errors.We should pay attention to the anatomic changes in target organs and anatomical structures during the course,individual radiotherapy was recommended to ensure adaptive doses.

  7. Effects of 415 MHz frequency on human lymphocyte genome

    International Nuclear Information System (INIS)

    Garaj-Vrhovac, V.; Fucic, A.; Kubelka, D.; Vojvodic, S.

    1996-01-01

    The continuously increasing use of artificial sources of electromagnetic radiation in industry and medicine has been accompanied in everyday life with telecommunication systems which is followed with great interest in possible hazardous effects of this type of radiation. The interesting applications of mobile telecommunications and the use of cellular phones are of topic interest. Numerous cytogenetic investigations are focused on the effects of microwave radiation from mobile communications frequency of 450 and 950 MHz on isolated cells in vitro. The aim of this work was to investigate the effects of microwaves from mobile telephone frequencies on human peripheral blood lymphocytes cultured in vitro. (author)

  8. Edaravone protects human peripheral blood lymphocytes from γ-irradiation-induced apoptosis and DNA damage.

    Science.gov (United States)

    Chen, Liming; Liu, Yinghui; Dong, Liangliang; Chu, Xiaoxia

    2015-03-01

    Radiation-induced cellular injury is attributed primarily to the harmful effects of free radicals, which play a key role in irradiation-induced apoptosis. In this study, we investigated the radioprotective efficacy of edaravone, a licensed clinical drug and a powerful free radical scavenger that has been tested against γ-irradiation-induced cellular damage in cultured human peripheral blood lymphocytes in studies of various diseases. Edaravone was pre-incubated with lymphocytes for 2 h prior to γ-irradiation. It was found that pretreatment with edaravone increased cell viability and inhibited generation of γ-radiation-induced reactive oxygen species (ROS) in lymphocytes exposed to 3 Gy γ-radiation. In addition, γ-radiation decreased antioxidant enzymatic activity, such as superoxide dismutase and glutathione peroxidase, as well as the level of reduced glutathione. Conversely, treatment with 100 μM edaravone prior to irradiation improved antioxidant enzyme activity and increased reduced glutathione levels in irradiated lymphocytes. Importantly, we also report that edaravone reduced γ-irradiation-induced apoptosis through downregulation of Bax, upregulation of Bcl-2, and consequent reduction of the Bax:Bcl-2 ratio. The current study shows edaravone to be an effective radioprotector against γ-irradiation-induced cellular damage in lymphocytes in vitro. Finally, edaravone pretreatment significantly reduced DNA damage in γ-irradiated lymphocytes, as measured by comet assay (% tail DNA, tail length, tail moment, and olive tail moment) (p edaravone offers protection from radiation-induced cytogenetic alterations.

  9. Effects of exogenous and endogenous IL-2 on irradiated human peripheral blood lymphocytes

    International Nuclear Information System (INIS)

    Zhang Lansheng; Wang Ninghai; Luan Meiling

    1993-08-01

    Human peripheral blood lymphocytes were irradiated with 1 to 40 Gy of γ-ray, and then cultured with PHA to prepare supernatant containing IL-2 for observation of kinetics of endogenous IL-2 production and reversion of lymphocyte proliferation after adding a highly purified IL-2. IL-2 activity was determined by the ability to sustain IL-2 dependent cell line (CTLL), lymphocyte proliferation was determined by 3 H-TdR incorporation and T lymphocyte subsets by monoclonal antibodies. The experimental results showed that lymphocytes exposed to 60 Co synthesized less DNA than nonirradiated lymphocytes. The inhibitory effect can partially reversed by purified IL-2 at the γ-ray dose range of 1 to 10 Gy, while irradiation with 2.5 Gy resulted in a reduction of T cells and T subsets, and increase in CD + 4 /CD + 8 ratio. The ratio of subsets recovered after adding IL-2. The kinetics of IL-2 production showed that the endogenous IL-2 production rose markedly with increasing dose of irradiation at the range of 1 to 10 Gy, and the peak of IL-2 production was at the γ-ray dose of 10 Gy

  10. Adaptive response induced by low concentrations of MMC in human peripheral lymphocytes

    International Nuclear Information System (INIS)

    Sun Shuqing; Wang Bin; Jiang Jie

    1998-01-01

    Samples of cultured human peripheral lymphocytes were pre-treated with mitomycin C (MMC) in concentrations of 0.01∼0.1 μg/mL at 34 h of incubation and then exposed to 1.5 Gy of X-rays. Chromosome aberrations, sister chromatid exchanges and micronuclei for these lymphocytes were observed. The results show that the chromosome aberration rates for lymphocytes pre-treated with MMC in concentrations of 0.5 and 0.075 μg/mL and the frequencies of sister chromatid exchanges for lymphocytes pre-treated with MMC in concentrations of 0.01 μg/mL were significantly lower than their own expected values but the rates of micronuclei for lymphocytes pre-treated with MMC in concentrations of 0.05, 0.075 and 0.1 μg/mL were significantly higher than the expected values. Such results suggest that for studying the cross resistance of lymphocytes to chemicals and ionizing radiation, inconsistent conclusions may be obtained if different endpoints are based on

  11. The study of chromosome aberration yield in human lymphocytes as an indicator of radiation dose. 1. Techniques

    International Nuclear Information System (INIS)

    Purrott, R.J.; Lloyd, D.C.

    1972-08-01

    Estimates of exposure to ionizing radiation can be obtained by determining the yield of chromosome aberrations in cultured human lymphocytes. Chromosomes can only be conveniently examined during cell division. The lymphocytes, which do not normally divide whilst circulating, are stimulated to divide during a 48-hour culture period. Two types of culture technique are described, one of which employs a lymphocyte-enriched inoculum and the other which uses whole blood. After culture the cells are harvested, dispensed onto slides and prepared for microscopic examination. An account is also given of the analysis of various types of radiation-induced chromosome aberrations and of the construction of calibration curves for certain types and rates of radiation which are used to interpret the aberration yields in terms of dose. (author)

  12. In vitro induction of lymphocyte responsiveness by a Strongylus vulgaris-derived mitogen.

    Science.gov (United States)

    Bailey, M; Lloyd, S; Martin, S C; Soulsby, E J

    1984-01-01

    Proliferation in vitro of peripheral blood lymphocytes both from horses infected with Strongylus vulgaris and from helminth-free ponies was observed in the presence of extracts of the fourth and fifth stage larvae and adults of S. vulgaris. In addition, S. vulgaris extracts induced transformation in cultures of peripheral blood lymphocytes from sheep and dogs and in mouse spleen cell cultures. Nylon wool non-adherent, T cell enriched fractions of lymphocytes from both mice and horses were stimulated by the S. vulgaris larval mitogen while no proliferation was observed in cultures containing nylon wool adherent, B cell enriched fractions. Macrophage co-operation appeared not to be necessary for S. vulgaris mitogen-induced transformation of spleen cells. The S. vulgaris mitogen stimulated a subpopulation of mouse spleen cells different from those responsive to PHA, Con A and LPS. These cells might be T helper cells since B cells were stimulated to proliferate in the presence of both T cells and S. vulgaris larval mitogen. In addition, the supernatant of in vitro cultured larvae of S. vulgaris induced slight, but significant transformation of equine peripheral blood lymphocytes. Therefore, it is possible that the S. vulgaris mitogen released by both viable parasites and degenerating larvae might induce T cell dependent production of immunoglobulin in vivo and account for the beta-globulinaemia, of which IgG(T) is a major component, in S vulgaris infected horses.

  13. In vitro effects of plant and mushroom extracts on immunological function of chicken lymphocytes and macrophages

    Science.gov (United States)

    The present study was conducted to examine the effects of milk thistle (Silybum marianum), turmeric (Curcuma longa), reishi mushroom (Ganoderma lucidum), and shiitake mushroom (Lentinus edodes) on innate immunity and tumor cell viability. In vitro culture of chicken spleen lymphocytes with extracts ...

  14. In Utero Exposure to Histological Chorioamnionitis Primes the Exometabolomic Profiles of Preterm CD4+ T Lymphocytes.

    Science.gov (United States)

    Matta, Poojitha; Sherrod, Stacy D; Marasco, Christina C; Moore, Daniel J; McLean, John A; Weitkamp, Joern-Hendrik

    2017-11-01

    Histological chorioamnionitis (HCA) is an intrauterine inflammatory condition that increases the risk for preterm birth, death, and disability because of persistent systemic and localized inflammation. The immunological mechanisms sustaining this response in the preterm newborn remain unclear. We sought to determine the consequences of HCA exposure on the fetal CD4 + T lymphocyte exometabolome. We cultured naive CD4 + T lymphocytes from HCA-positive and -negative preterm infants matched for gestational age, sex, race, prenatal steroid exposure, and delivery mode. We collected conditioned media samples before and after a 6-h in vitro activation of naive CD4 + T lymphocytes with soluble staphylococcal enterotoxin B and anti-CD28. We analyzed samples by ultraperformance liquid chromatography ion mobility-mass spectrometry. We determined the impact of HCA on the CD4 + T lymphocyte exometabolome and identified potential biomarker metabolites by multivariate statistical analyses. We discovered that: 1) CD4 + T lymphocytes exposed to HCA exhibit divergent exometabolomic profiles in both naive and activated states; 2) ∼30% of detected metabolites differentially expressed in response to activation were unique to HCA-positive CD4 + T lymphocytes; 3) metabolic pathways associated with glutathione detoxification and tryptophan degradation were altered in HCA-positive CD4 + T lymphocytes; and 4) flow cytometry and cytokine analyses suggested a bias toward a T H 1-biased immune response in HCA-positive samples. HCA exposure primes the neonatal adaptive immune processes by inducing changes to the exometabolomic profile of fetal CD4 + T lymphocytes. These exometabolomic changes may link HCA exposure to T H 1 polarization of the neonatal adaptive immune response. Copyright © 2017 by The American Association of Immunologists, Inc.

  15. Damage of chromosoms under irradiation of human blood lymphocytes and development of bystander effect.

    Science.gov (United States)

    Shemetun, O V

    2016-12-01

    the research the distribution of radiation induced damages among chromosomes and their bands in irra diated in vitro human blood lymphocytes and in unirradiated bystander cells.Material and methods of research: cultivation of human peripheral blood lymphocytes by semi micromethod D.A. Hungerford, modeling of radiation induced bystander effect in mixed cultures consisting of irradiated in vitro and non irradiated blood lymphocytes from persons of different gender, GTG staining of metaphase chromosomes and their cytogenetic analysis. Break points in chromosomes under the formation of aberrations were identified in exposed in vitro human peripheral blood lymphocytes in doses 0.25 Gy (95 breaks in 1248 cells) and 1.0 Gy (227 breaks in 726 cells) and in non irradiated bystander cells under their joint cultivation with irradiated in vitro human lymphocytes (51 breaks in 1137 cells at irradiation of adjacent populations of lymphocytes in dose 0.25 Gy and 75 breaks in 1321 cells at irradiation of adjacent population of lymphocytes in a dose 1.0 Gy). The distribution of injuries among the chromo somes and their bands was investigated. in radiation exposed in vitro human peripheral blood lymphocytes as well as in bystander cells the fre quency of damaged bands and number of breaks which localized in them exceeded the control value (p chromosomes were damaged according to their relative length. Location of bands with increasing number of breaks coincided with the «hot spots» of chromosome damage following irradiation and fragile sites. More sensitive to damage were G negative euchromatin chromosome bands, in which were localized 82 88 % breaks. Damageability of telomeric regions in the irradiated cells had no significant difference from the control, while in bystander cells was lower than control value (p < 0.05). O. V. Shemetun.

  16. Dosimetric and delivery efficiency investigation for treating hepatic lesions with a MLC-equipped robotic radiosurgery–radiotherapy combined system

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Lihui, E-mail: lihui.jin@fccc.edu; Price, Robert A.; Wang, Lu; Meyer, Joshua; Fan, James; Charlie Ma, Chang Ming [Department of Radiation Oncology, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, Pennsylvania 19111 (United States)

    2016-02-15

    Purpose: The CyberKnife M6 (CK-M6) Series introduced a multileaf collimator (MLC) for extending its capability from stereotactic radiosurgery/stereotactic radiotherapy (SBRT) to conventionally fractionated radiotherapy. This work is to investigate the dosimetric quality of plans that are generated using MLC-shaped beams on the CK-M6, as well as their delivery time, via comparisons with the intensity modulated radiotherapy plans that were clinically used on a Varian Linac for treating hepatic lesions. Methods: Nine patient cases were selected and divided into three groups with three patients in each group: (1) the group-one patients were treated conventionally (25 fractions); (2) the group-two patients were treated with SBRT-like hypofractionation (5 fractions); and (3) the group-three patients were treated similar to group-one patients, but with two planning target volumes (PTVs) and two different prescription dose levels correspondingly. The clinically used plans were generated on the ECLIPSE treatment planning system (TPS) and delivered on a Varian Linac (E-V plans). The multiplan (MP) TPS was used to replan these clinical cases with the MLC as the beam device for the CK-M6 (C-M plans). After plans were normalized to the same PTV dose coverage, comparisons between the C-M and E-V plans were performed based on D{sub 99%} (percentage of prescription dose received by 99% of the PTV), D{sub 0.1cm{sup 3}} (the percentage of prescription dose to 0.1 cm{sup 3} of the PTV), and doses received by critical structures. Then, the delivery times for the C-M plans will be obtained, which are the MP TPS generated estimations assuming having an imaging interval of 60 s. Results: The difference in D{sub 99%} between C-M and E-V plans is +0.6% on average (+ or − indicating a higher or lower dose from C-M plans than from E-V plans) with a range from −4.1% to +3.8%, and the difference in D{sub 0.1cm{sup 3}} was −1.0% on average with a range from −5.1% to +2.9%. The PTV

  17. Dosimetric and delivery efficiency investigation for treating hepatic lesions with a MLC-equipped robotic radiosurgery–radiotherapy combined system

    International Nuclear Information System (INIS)

    Jin, Lihui; Price, Robert A.; Wang, Lu; Meyer, Joshua; Fan, James; Charlie Ma, Chang Ming

    2016-01-01

    Purpose: The CyberKnife M6 (CK-M6) Series introduced a multileaf collimator (MLC) for extending its capability from stereotactic radiosurgery/stereotactic radiotherapy (SBRT) to conventionally fractionated radiotherapy. This work is to investigate the dosimetric quality of plans that are generated using MLC-shaped beams on the CK-M6, as well as their delivery time, via comparisons with the intensity modulated radiotherapy plans that were clinically used on a Varian Linac for treating hepatic lesions. Methods: Nine patient cases were selected and divided into three groups with three patients in each group: (1) the group-one patients were treated conventionally (25 fractions); (2) the group-two patients were treated with SBRT-like hypofractionation (5 fractions); and (3) the group-three patients were treated similar to group-one patients, but with two planning target volumes (PTVs) and two different prescription dose levels correspondingly. The clinically used plans were generated on the ECLIPSE treatment planning system (TPS) and delivered on a Varian Linac (E-V plans). The multiplan (MP) TPS was used to replan these clinical cases with the MLC as the beam device for the CK-M6 (C-M plans). After plans were normalized to the same PTV dose coverage, comparisons between the C-M and E-V plans were performed based on D_9_9_% (percentage of prescription dose received by 99% of the PTV), D_0_._1_c_m_"3 (the percentage of prescription dose to 0.1 cm"3 of the PTV), and doses received by critical structures. Then, the delivery times for the C-M plans will be obtained, which are the MP TPS generated estimations assuming having an imaging interval of 60 s. Results: The difference in D_9_9_% between C-M and E-V plans is +0.6% on average (+ or − indicating a higher or lower dose from C-M plans than from E-V plans) with a range from −4.1% to +3.8%, and the difference in D_0_._1_c_m_"3 was −1.0% on average with a range from −5.1% to +2.9%. The PTV conformity index (CI) for

  18. Lymphocytes from wasted mice express enhanced spontaneous and {gamma}-ray-induced apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Woloschak, G.E. [Argonne National Lab., IL (United States)]|[Loyola Univ. Medical Center, Maywood, IL (United States); Chang-Liu, Chin-Mei [Argonne National Lab., IL (United States); Chung, Jen; Libertin, C.R. [Loyola Univ. Medical Center, Maywood, IL (United States)

    1993-09-01

    Mice bearing the autosomal recessive mutation wasted (wst/wst) display a disease pattern including faulty repair of DNA damage in lymphocytes after radiation exposure, neurologic abnormalities, and immunodeficiency. Many of the features of this mouse model have suggested a premature or increased spontaneous frequency of apoptosis in thymocytes; past work has shown an inability to establish cultured T cell lines, an abnormally high death rate of stimulated T cells in culture, and an increased sensitivity of T cells to the killing effects of ionizing radiations in wst/wst mice relative to controls. The experiments reported here were designed to examine splenic and thymic lymphocytes from wasted and control mice for signs of early apoptosis. Our results revealed enhanced expression of Rp-8 mRNA (associated with apoptosis) in thymic lymphocytes and reduced expression in splenic lymphocytes of wst/wst mice relative to controls; expression of Rp-2 and Td-30 mRNA (induced during apoptosis) were not detectable in spleen or thymus. Higher spontaneous DNA fragmentation was observed in wasted mice than in controls; however, {gamma}-ray-induced DNA fragmentation peaked at a lower dose and occurred to a greater extent in wasted mice relative to controls. These results provide evidence for high spontaneous and {gamma}-ray-induced apoptosis in T cells of wasted mice as a mechanism underlying the observed lymphocyte and DNA repair abnormalities.

  19. Preliminary studies for implementation of a MCL quality control using EPID (Portal Dosimetry); Estudos preliminares para implementacao de um controle de qualidade de MLC com o uso do EPID (Portal Dosimetry)

    Energy Technology Data Exchange (ETDEWEB)

    Mattos, Fabio R.; Furnari, Laura [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina

    2016-07-01

    A Quality Control (CQ) to ensure the expected performance of a Multileaf Collimator System (MLC) is essential for delivering dose in a safety and appropriate way. The time required for equipment control and dosimetry may be lowered when the Electronic Portal Image Device (EPID) is used. The aim of this paper was to check the resolution limits of the detection system for IMRT mode, and to do the analysis of three tests of MLC performance: Picket Fence, Slinding GAP, MLC versus Gantry. A Varian iX Clinac equipped with an 80 leaf Millennium MLC and with amorphous silicon based EPID (aS1000) was use. The EPID proved Effective, where errors up to 0,5 mm can be detected. Information about interleaf transmissions, dose profile and gravity influence in the leaf banks also were included. (author)

  20. Management of chronic lymphocytic leukemia.

    Science.gov (United States)

    Stilgenbauer, Stephan; Furman, Richard R; Zent, Clive S

    2015-01-01

    Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) is usually diagnosed in asymptomatic patients with early-stage disease. The standard management approach is careful observation, irrespective of risk factors unless patients meet the International Workshop on CLL (IWCLL) criteria for "active disease," which requires treatment. The initial standard therapy for most patients combines an anti-CD20 antibody (such as rituximab, ofatumumab, or obinutuzumab) with chemotherapy (fludarabine/cyclophosphamide [FC], bendamustine, or chlorambucil) depending on multiple factors including the physical fitness of the patient. However, patients with very high-risk CLL because of a 17p13 deletion (17p-) with or without mutation of TP53 (17p-/TP53mut) have poor responses to chemoimmunotherapy and require alternative treatment regimens containing B-cell receptor (BCR) signaling pathway inhibitors. The BCR signaling pathway inhibitors (ibrutinib targeting Bruton's tyrosine kinase [BTK] and idelalisib targeting phosphatidyl-inositol 3-kinase delta [PI3K-delta], respectively) are currently approved for the treatment of relapsed/refractory CLL and all patients with 17p- (ibrutinib), and in combination with rituximab for relapsed/refractory patients (idelalisib). These agents offer great efficacy, even in chemotherapy refractory CLL, with increased tolerability, safety, and survival. Ongoing studies aim to determine the best therapy combinations with the goal of achieving long-term disease control and the possibility of developing a curative regimen for some patients. CLL is associated with a wide range of infectious, autoimmune, and malignant complications. These complications result in considerable morbidity and mortality that can be minimized by early detection and aggressive management. This active monitoring requires ongoing patient education, provider vigilance, and a team approach to patient care.

  1. SU-E-T-605: Performance Evaluation of MLC Leaf-Sequencing Algorithms in Head-And-Neck IMRT

    International Nuclear Information System (INIS)

    Jing, J; Lin, H; Chow, J

    2015-01-01

    Purpose: To investigate the efficiency of three multileaf collimator (MLC) leaf-sequencing algorithms proposed by Galvin et al, Chen et al and Siochi et al using external beam treatment plans for head-and-neck intensity modulated radiation therapy (IMRT). Methods: IMRT plans for head-and-neck were created using the CORVUS treatment planning system. The plans were optimized and the fluence maps for all photon beams determined. Three different MLC leaf-sequencing algorithms based on Galvin et al, Chen et al and Siochi et al were used to calculate the final photon segmental fields and their monitor units in delivery. For comparison purpose, the maximum intensity of fluence map was kept constant in different plans. The number of beam segments and total number of monitor units were calculated for the three algorithms. Results: From results of number of beam segments and total number of monitor units, we found that algorithm of Galvin et al had the largest number of monitor unit which was about 70% larger than the other two algorithms. Moreover, both algorithms of Galvin et al and Siochi et al have relatively lower number of beam segment compared to Chen et al. Although values of number of beam segment and total number of monitor unit calculated by different algorithms varied with the head-and-neck plans, it can be seen that algorithms of Galvin et al and Siochi et al performed well with a lower number of beam segment, though algorithm of Galvin et al had a larger total number of monitor units than Siochi et al. Conclusion: Although performance of the leaf-sequencing algorithm varied with different IMRT plans having different fluence maps, an evaluation is possible based on the calculated number of beam segment and monitor unit. In this study, algorithm by Siochi et al was found to be more efficient in the head-and-neck IMRT. The Project Sponsored by the Fundamental Research Funds for the Central Universities (J2014HGXJ0094) and the Scientific Research Foundation for the

  2. SU-E-T-605: Performance Evaluation of MLC Leaf-Sequencing Algorithms in Head-And-Neck IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Jing, J; Lin, H [Hefei University of Technology, Hefei, Anhui (China); Chow, J [Princess Margaret Hospital, Toronto, ON (Canada)

    2015-06-15

    Purpose: To investigate the efficiency of three multileaf collimator (MLC) leaf-sequencing algorithms proposed by Galvin et al, Chen et al and Siochi et al using external beam treatment plans for head-and-neck intensity modulated radiation therapy (IMRT). Methods: IMRT plans for head-and-neck were created using the CORVUS treatment planning system. The plans were optimized and the fluence maps for all photon beams determined. Three different MLC leaf-sequencing algorithms based on Galvin et al, Chen et al and Siochi et al were used to calculate the final photon segmental fields and their monitor units in delivery. For comparison purpose, the maximum intensity of fluence map was kept constant in different plans. The number of beam segments and total number of monitor units were calculated for the three algorithms. Results: From results of number of beam segments and total number of monitor units, we found that algorithm of Galvin et al had the largest number of monitor unit which was about 70% larger than the other two algorithms. Moreover, both algorithms of Galvin et al and Siochi et al have relatively lower number of beam segment compared to Chen et al. Although values of number of beam segment and total number of monitor unit calculated by different algorithms varied with the head-and-neck plans, it can be seen that algorithms of Galvin et al and Siochi et al performed well with a lower number of beam segment, though algorithm of Galvin et al had a larger total number of monitor units than Siochi et al. Conclusion: Although performance of the leaf-sequencing algorithm varied with different IMRT plans having different fluence maps, an evaluation is possible based on the calculated number of beam segment and monitor unit. In this study, algorithm by Siochi et al was found to be more efficient in the head-and-neck IMRT. The Project Sponsored by the Fundamental Research Funds for the Central Universities (J2014HGXJ0094) and the Scientific Research Foundation for the

  3. Evolution and phylogeny of B lymphocytes

    Directory of Open Access Journals (Sweden)

    Fabiola Claudio-Piedras

    2016-05-01

    Full Text Available B lymphocytes are one of the most important cell types involved in the immune response of mammals. The origin and evolution of this cellular type is unknown, but the B lymphocyte bona fide appeared first in fish. In this review we analize the principal components of the immune response of invertebrates, their phylogenetic distribution and the permancence of some properties that allowed the emergence of the B lymphocyte. We started from the idea that many of the components that characterize the B lymphocyte are found distributed among the invertebrates, however, it is in the B lymphocyte, where all these components that give this type of cell its identity, converged. The actual knowledge we have in regards of the lymphocytes comes, in the most part, from physiological studies in mammals, being the mice the more representative. The origin of the B lymphocyte, its alternative mechanisms for generating receptor diversity, its immune effector response, and the generation of memory, require an evolutionary and multidisiplinary approach for its study.

  4. Hypoxic contraction of cultured pulmonary vascular smooth muscle cells

    International Nuclear Information System (INIS)

    Murray, T.R.; Chen, L.; Marshall, B.E.; Macarak, E.J.

    1990-01-01

    The cellular events involved in generating the hypoxic pulmonary vasoconstriction response are not clearly understood, in part because of the multitude of factors that alter pulmonary vascular tone. The goal of the present studies was to determine if a cell culture preparation containing vascular smooth muscle (VSM) cells could be made to contract when exposed to a hypoxic atmosphere. Cultures containing only fetal bovine pulmonary artery VSM cells were assessed for contractile responses to hypoxic stimuli by two methods. In the first, tension forces generated by cells grown on a flexible growth surface (polymerized polydimethyl siloxane) were manifested as wrinkles and distortions of the surface under the cells. Wrinkling of the surface was noted to progressively increase with time as the culture medium bathing the cells was made hypoxic (PO2 approximately 25 mmHg). The changes were sometimes reversible upon return to normoxic conditions and appeared to be enhanced in cells already exhibiting evidence of some baseline tone. Repeated passage in culture did not diminish the hypoxic response. Evidence for contractile responses to hypoxia was also obtained from measurements of myosin light chain (MLC) phosphorylation. Conversion of MLC to the phosphorylated species is an early step in the activation of smooth muscle contraction. Lowering the PO2 in the culture medium to 59 mmHg caused a 45% increase in the proportion of MLC in the phosphorylated form as determined by two-dimensional gel electrophoresis. Similarly, cultures preincubated for 4 h with 32P and then exposed to normoxia or hypoxia for a 5-min experimental period showed more than twice as much of the label in MLCs of the hypoxic cells

  5. SU-E-T-627: Precision Modelling of the Leaf-Bank Rotation in Elekta’s Agility MLC: Is It Necessary?

    Energy Technology Data Exchange (ETDEWEB)

    Vujicic, M; Belec, J [Ottawa Hospital Cancer Centre, Ottawa, ON (Canada); Heath, E; Gholampourkashi, S [Carleton University, Ottawa, ON (Canada); Cygler, J [The Ottawa Hospital Cancer Centre, Ottawa, ON (Canada)

    2015-06-15

    Purpose: To demonstrate the method used to determine the leaf bank rotation angle (LBROT) as a parameter for modeling the Elekta Agility multi-leaf collimator (MLC) for Monte Carlo simulations and to evaluate the clinical impact of LBROT. Methods: A detailed model of an Elekta Infinity linac including an Agility MLC was built using the EGSnrc/BEAMnrc Monte Carlo code. The Agility 160-leaf MLC is modelled using the MLCE component module which allows for leaf bank rotation using the parameter LBROT. A precise value of LBROT is obtained by comparing measured and simulated profiles of a specific field, which has leaves arranged in a repeated pattern such that one leaf is opened and the adjacent one is closed. Profile measurements from an Agility linac are taken with gafchromic film, and an ion chamber is used to set the absolute dose. The measurements are compared to Monte Carlo (MC) simulations and the LBROT is adjusted until a match is found. The clinical impact of LBROT is evaluated by observing how an MC dose calculation changes with LBROT. A clinical Stereotactic Body Radiation Treatment (SBRT) plan is calculated using BEAMnrc/DOSXYZnrc simulations with different input values for LBROT. Results: Using the method outlined above, the LBROT is determined to be 9±1 mrad. Differences as high as 4% are observed in a clinical SBRT plan between the extreme case (LBROT not modeled) and the nominal case. Conclusion: In small-field radiation therapy treatment planning, it is important to properly account for LBROT as an input parameter for MC dose calculations with the Agility MLC. More work is ongoing to elucidate the observed differences by determining the contributions from transmission dose, change in field size, and source occlusion, which are all dependent on LBROT. This work was supported by OCAIRO (Ontario Consortium of Adaptive Interventions in Radiation Oncology), funded by the Ontario Research Fund.

  6. SU-E-T-627: Precision Modelling of the Leaf-Bank Rotation in Elekta’s Agility MLC: Is It Necessary?

    International Nuclear Information System (INIS)

    Vujicic, M; Belec, J; Heath, E; Gholampourkashi, S; Cygler, J

    2015-01-01

    Purpose: To demonstrate the method used to determine the leaf bank rotation angle (LBROT) as a parameter for modeling the Elekta Agility multi-leaf collimator (MLC) for Monte Carlo simulations and to evaluate the clinical impact of LBROT. Methods: A detailed model of an Elekta Infinity linac including an Agility MLC was built using the EGSnrc/BEAMnrc Monte Carlo code. The Agility 160-leaf MLC is modelled using the MLCE component module which allows for leaf bank rotation using the parameter LBROT. A precise value of LBROT is obtained by comparing measured and simulated profiles of a specific field, which has leaves arranged in a repeated pattern such that one leaf is opened and the adjacent one is closed. Profile measurements from an Agility linac are taken with gafchromic film, and an ion chamber is used to set the absolute dose. The measurements are compared to Monte Carlo (MC) simulations and the LBROT is adjusted until a match is found. The clinical impact of LBROT is evaluated by observing how an MC dose calculation changes with LBROT. A clinical Stereotactic Body Radiation Treatment (SBRT) plan is calculated using BEAMnrc/DOSXYZnrc simulations with different input values for LBROT. Results: Using the method outlined above, the LBROT is determined to be 9±1 mrad. Differences as high as 4% are observed in a clinical SBRT plan between the extreme case (LBROT not modeled) and the nominal case. Conclusion: In small-field radiation therapy treatment planning, it is important to properly account for LBROT as an input parameter for MC dose calculations with the Agility MLC. More work is ongoing to elucidate the observed differences by determining the contributions from transmission dose, change in field size, and source occlusion, which are all dependent on LBROT. This work was supported by OCAIRO (Ontario Consortium of Adaptive Interventions in Radiation Oncology), funded by the Ontario Research Fund

  7. SU-E-T-774: Use of a Scintillator-Mirror-Camera System for the Measurement of MLC Leakage Radiation with the CyberKnife M6 System

    Energy Technology Data Exchange (ETDEWEB)

    Goggin, L; Kilby, W; Noll, M; Maurer, C [Accuray Inc, Sunnyvale, CA (United States)

    2015-06-15

    Purpose: A technique using a scintillator-mirror-camera system to measure MLC leakage was developed to provide an efficient alternative to film dosimetry while maintaining high spatial resolution. This work describes the technique together with measurement uncertainties. Methods: Leakage measurements were made for the InCise™ MLC using the Logos XRV-2020A device. For each measurement approximately 170 leakage and background images were acquired using optimized camera settings. Average background was subtracted from each leakage frame before filtering the integrated leakage image to replace anomalous pixels. Pixel value to dose conversion was performed using a calibration image. Mean leakage was calculated within an ROI corresponding to the primary beam, and maximum leakage was determined by binning the image into overlapping 1mm x 1mm ROIs. 48 measurements were performed using 3 cameras and multiple MLC-linac combinations in varying beam orientations, with each compared to film dosimetry. Optical and environmental influences were also investigated. Results: Measurement time with the XRV-2020A was 8 minutes vs. 50 minutes using radiochromic film, and results were available immediately. Camera radiation exposure degraded measurement accuracy. With a relatively undamaged camera, mean leakage agreed with film measurement to ≤0.02% in 92% cases, ≤0.03% in 100% (for maximum leakage the values were 88% and 96%) relative to reference open field dose. The estimated camera lifetime over which this agreement is maintained is at least 150 measurements, and can be monitored using reference field exposures. A dependency on camera temperature was identified and a reduction in sensitivity with distance from image center due to optical distortion was characterized. Conclusion: With periodic monitoring of the degree of camera radiation damage, the XRV-2020A system can be used to measure MLC leakage. This represents a significant time saving when compared to the traditional

  8. SU-G-TeP4-07: Automatic EPID-Based 2D Measurement of MLC Leaf Offset as a Quality Control Tool

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, T; Moran, J [The University of Michigan, Ann Arbor, MI (United States); Schultz, B [University of Michigan, Ann Arbor, MI (United States); Kim, G [University of California, San Diego, La Jolla, CA (United States); Barnes, M [Calvary Mater Hospital Newcastle, Warratah, NSW (Australia); Perez, M [North Sydney Cancer Center, Sydney (Australia); Farrey, K [University of Chicago, Chicago, IL (United States); Popple, R [University Alabama Birmingham, Birmingham, AL (United States); Greer, P [Calvary Mater Newcastle, Newcastle (Australia)

    2016-06-15

    Purpose: The MLC dosimetric leaf gap (DLG) and transmission are measured parameters which impact the dosimetric accuracy of IMRT and VMAT plans. This investigation aims to develop an efficient and accurate routine constancy check of the physical DLG in two dimensions. Methods: The manufacturer’s recommended DLG measurement method was modified by using 5 fields instead of 11 and by utilizing the Electronic Portal Imaging Device (EPID). Validations were accomplished using an ion chamber (IC) in solid water and a 2D IC array. EPID data was collected for 6 months on multiple TrueBeam linacs using both Millennium and HD MLCs at 5 different clinics in an international consortium. Matlab code was written to automatically analyze the images and calculate the 2D results. Sensitivity was investigated by introducing deliberate leaf position errors. MLC calibration and initialization history was recorded to allow quantification of their impact. Results were analyzed using statistical process control (SPC). Results: The EPID method took approximately 5 minutes. Due to detector response, the EPID measured DLG and transmission differed from the IC values but were reproducible and consistent with changes measured using the ICs. For the Millennium MLC, the EPID measured DLG and transmission were both consistently lower than IC results. The EPID method was implemented as leaf offset and transmission constancy tests (LOC and TC). Based on 6 months of measurements, the initial leaf-specific action thresholds for changes from baseline were set to 0.1 mm. Upper and lower control limits for variation were developed for each machine. Conclusion: Leaf offset and transmission constancy tests were implemented on Varian HD and Millennium MLCs using an EPID and found to be efficient and accurate. The test is effective for monitoring MLC performance using dynamic delivery and performing process control on the DLG in 2D, thus enhancing dosimetric accuracy. This work was supported by a grant

  9. Airborne particulate matter in vitro exposure induces cytoskeleton remodeling through activation of the ROCK-MYPT1-MLC pathway in A549 epithelial lung cells.

    Science.gov (United States)

    Chirino, Yolanda I; García-Cuellar, Claudia María; García-García, Carlos; Soto-Reyes, Ernesto; Osornio-Vargas, Álvaro Román; Herrera, Luis A; López-Saavedra, Alejandro; Miranda, Javier; Quintana-Belmares, Raúl; Pérez, Irma Rosas; Sánchez-Pérez, Yesennia

    2017-04-15

    Airborne particulate matter with an aerodynamic diameter ≤10μm (PM 10 ) is considered a risk factor for the development of lung cancer. Little is known about the cellular mechanisms by which PM 10 is associated with cancer, but there is evidence that its exposure can lead to an acquired invasive phenotype, apoptosis evasion, inflammasome activation, and cytoskeleton remodeling in lung epithelial cells. Cytoskeleton remodeling occurs through actin stress fiber formation, which is partially regulated through ROCK kinase activation, we aimed to investigate if this protein was activated in response to PM 10 exposure in A549 lung epithelial cells. Results showed that 10μg/cm 2 of PM 10 had no influence on cell viability but increased actin stress fibers, cytoplasmic ROCK expression, and phosphorylation of myosin phosphatase-targeting 1 (MYPT1) and myosin light chain (MLC) proteins, which are targeted by ROCK. The inhibition of ROCK prevented actin stress fiber formation and the phosphorylation of MYPT1 and MLC, suggesting that PM 10 activated the ROCK-MYPT1-MLC pathway in lung epithelial cells. The activation of ROCK1 has been involved in the acquisition of malignant phenotypes, and its induction by PM 10 exposure could contribute to the understanding of PM 10 as a risk factor for cancer development through the mechanisms associated with invasive phenotype. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Lymphocytic Pleural Effusion in Acute Melioidosis

    Directory of Open Access Journals (Sweden)

    Kuo-Mou Chung

    2007-10-01

    Full Text Available An endemic outbreak of melioidosis developed in southern Taiwan following a flood caused by a typhoon in July 2005. A total of 27 patients were diagnosed with the acute and indigenous form of pulmonary melioidosis. Parapneumonic pleural effusions were noted on chest X-rays in six patients. Thoracentesis was done in three patients and all revealed lymphocyte predominance in differential cell count. Burkholderia pseudomallei was isolated in the pleural effusion in one of them. All three patients survived after antibiotic treatment. Lymphocytic pleural effusion is generally seen in tuberculosis or malignancy. However, our findings suggest that melioidosis should be considered in the differential diagnosis of lymphocytic pleural effusion.

  11. Effects of mercury on the proliferation of human peripheral lymphocytes in vitro

    International Nuclear Information System (INIS)

    Piwecka, K.; Poniedzialek, B.; Rzymski, P.; Karczewski, J.; Zurawski, J.; Wiktorowicz, K.

    2011-01-01

    Our project aimed to investigate the effects of mercury on the proliferation of human peripheral lymphocytes in vitro. The lymphocytes were isolated from the blood collected from healthy donors at Regionalne Centrum Krwiodawstwa i Krwiolecznictwa in Poznan, Poland. For the purpose of cell culture, the lymphocyte suspension (25 · 10 4 cells/ml) in Eagle's medium supplemented with 10% fetal calf serum was prepared. Phytohaemagglutinin-L (PHA-L) was used in a concentration of 2.5 mg/ml to stimulate cell proliferation. Mercuric chloride (HgCl 2 ) in four different concentrations (1 μM, 10 μM, 50 μM, 100 μM) and [3H]-thymidine were added after 48 hours of incubation and the cell culture was continued for the next 24 hours. The rate of lymphocyte proliferation was measured by [3H]-thymidine incorporation method with a liquid scintillation counter. Results indicate that higher concentrations of mercury (50 μM, 100 μM) inhibit the [3H]-thymidine incorporation of human peripheral lymphocytes in vitro. The incorporation was lower than the control sample by 65% at a concentration of 50 μM, while at a concentration of 100 μM it fell to virtually zero. Moreover, the phase of lymphocyte proliferation cycle affected by mercuric chloride was also investigated. For this purpose HgCl 2 in 2 concentrations (10 μM, 50 μM) was added to the cell culture in 4 different time points: at the start of the cell culture and after 4, 24, and 48 hours of incubation. After 48 hours, [3H]-thymidine was added and the cell culture was continued for an additional 24 hours. The rate of cell proliferation was estimated by [3H]-thymidine incorporation using a liquid scintillation counter. The inhibition effect was observed in samples with metal added at the start of the cell culture and after 4 h of incubation, i.e. at the initial phase of the lymphocyte proliferation cycle. (authors)

  12. Behavior of the nucleic acid ethidium complex sedimentation of human lymphocytes after gamma irradiation

    International Nuclear Information System (INIS)

    Langrock, K.

    1982-01-01

    Under standardized conditions the repair kinetic test by Fender and Hartwig demonstrates the dose dependence of the injury of the nucleic acid complex of human lymphocytes after gamma irradiation and their repair even in low dose regions. Seasonal changes with infect incubation, individual variability in the lymphocyte population and culture conditions are to be proved before clinical application of the test in radiotherapy to generalize the influence of the factors. 3.4 up to 6 μg/ml ethidium bromide should be chosen as an optimum ethidium concentration of the gradient. (author)

  13. WE-A-304-01: Strategies and Technologies for Cranial Radiosurgery Planning: MLC-Based Linac

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G. [University of California, San Diego (United States)

    2015-06-15

    The high fractional doses, stringent requirements for accuracy and precision, and surgical perspective characteristic of intracranial radiosurgery create considerations for treatment planning which are distinct from most other radiotherapy procedures. This session will introduce treatment planning techniques specific to two popular intracranial SRS modalities: Gamma Knife and MLC-based Linac. The basic treatment delivery characteristics of each device will be reviewed with a focus on how those characteristics determine the paradigm used for treatment planning. Basic techniques for treatment planning will be discussed, including considerations such as isodose selection, target and organ-at-risk definition, quality indices, and protection of critical structures. Future directions for SRS treatment planning will also be discussed. Learning Objectives: Introduce the basic physical principles of intracranial radiosurgery and how they are realized in the treatment planning paradigms for Gamma Knife and Linac radiosurgery. Demonstrate basic treatment planning techniques. Discuss metrics for evaluating SRS treatment plan quality. Discuss recent and future advances in SRS treatment planning. D. Schlesinger receives research support from Elekta, AB.

  14. Treatment planning systems for external whole brain radiation therapy: With and without MLC (multi leaf collimator) optimization

    Science.gov (United States)

    Budiyono, T.; Budi, W. S.; Hidayanto, E.

    2016-03-01

    Radiation therapy for brain malignancy is done by giving a dose of radiation to a whole volume of the brain (WBRT) followed by a booster at the primary tumor with more advanced techniques. Two external radiation fields given from the right and left side. Because the shape of the head, there will be an unavoidable hotspot radiation dose of greater than 107%. This study aims to optimize planning of radiation therapy using field in field multi-leaf collimator technique. A study of 15 WBRT samples with CT slices is done by adding some segments of radiation in each field of radiation and delivering appropriate dose weighting using a TPS precise plan Elekta R 2.15. Results showed that this optimization a more homogeneous radiation on CTV target volume, lower dose in healthy tissue, and reduced hotspots in CTV target volume. Comparison results of field in field multi segmented MLC technique with standard conventional technique for WBRT are: higher average minimum dose (77.25% ± 0:47%) vs (60% ± 3:35%); lower average maximum dose (110.27% ± 0.26%) vs (114.53% ± 1.56%); lower hotspot volume (5.71% vs 27.43%); and lower dose on eye lenses (right eye: 9.52% vs 18.20%); (left eye: 8.60% vs 16.53%).

  15. Treatment planning systems for external whole brain radiation therapy: With and without MLC (multi leaf collimator) optimization

    International Nuclear Information System (INIS)

    Budiyono, T; Budi, W S; Hidayanto, E

    2016-01-01

    Radiation therapy for brain malignancy is done by giving a dose of radiation to a whole volume of the brain (WBRT) followed by a booster at the primary tumor with more advanced techniques. Two external radiation fields given from the right and left side. Because the shape of the head, there will be an unavoidable hotspot radiation dose of greater than 107%. This study aims to optimize planning of radiation therapy using field in field multi-leaf collimator technique. A study of 15 WBRT samples with CT slices is done by adding some segments of radiation in each field of radiation and delivering appropriate dose weighting using a TPS precise plan Elekta R 2.15. Results showed that this optimization a more homogeneous radiation on CTV target volume, lower dose in healthy tissue, and reduced hotspots in CTV target volume. Comparison results of field in field multi segmented MLC technique with standard conventional technique for WBRT are: higher average minimum dose (77.25% ± 0:47%) vs (60% ± 3:35%); lower average maximum dose (110.27% ± 0.26%) vs (114.53% ± 1.56%); lower hotspot volume (5.71% vs 27.43%); and lower dose on eye lenses (right eye: 9.52% vs 18.20%); (left eye: 8.60% vs 16.53%). (paper)

  16. WE-A-304-01: Strategies and Technologies for Cranial Radiosurgery Planning: MLC-Based Linac

    International Nuclear Information System (INIS)

    Kim, G.

    2015-01-01

    The high fractional doses, stringent requirements for accuracy and precision, and surgical perspective characteristic of intracranial radiosurgery create considerations for treatment planning which are distinct from most other radiotherapy procedures. This session will introduce treatment planning techniques specific to two popular intracranial SRS modalities: Gamma Knife and MLC-based Linac. The basic treatment delivery characteristics of each device will be reviewed with a focus on how those characteristics determine the paradigm used for treatment planning. Basic techniques for treatment planning will be discussed, including considerations such as isodose selection, target and organ-at-risk definition, quality indices, and protection of critical structures. Future directions for SRS treatment planning will also be discussed. Learning Objectives: Introduce the basic physical principles of intracranial radiosurgery and how they are realized in the treatment planning paradigms for Gamma Knife and Linac radiosurgery. Demonstrate basic treatment planning techniques. Discuss metrics for evaluating SRS treatment plan quality. Discuss recent and future advances in SRS treatment planning. D. Schlesinger receives research support from Elekta, AB

  17. Theileria parva infection induces autocrine growth of bovine lymphocytes.

    Science.gov (United States)

    Dobbelaere, D A; Coquerelle, T M; Roditi, I J; Eichhorn, M; Williams, R O

    1988-01-01

    Bovine lymphocytes infected with the parasite Theileria parva continuously secrete a growth factor that is essential for their proliferation in vitro and also constitutively express interleukin 2 receptors on their surface. Dilution of the secreted growth factor, caused by culturing cells at low density, results in retardation of culture growth. Human recombinant interleukin 2, however, effectively substitutes for the diluted growth factor by restoring normal growth rates and also allows Theileria-infected cells to be grown at low density without the use of feeder layers. Secretion of the growth factor and expression of the interleukin 2 receptor depend on the presence of the parasite in the cytoplasm of the host cell. Elimination of the parasite from the cell cytoplasm by the specific antitheilerial drug BW 720c results in the arrest of growth factor secretion and the disappearance of interleukin 2 receptors from the cell surface. This is accompanied by growth arrest and reversion of the infected cells to the morphology of resting lymphocytes. We propose that the continuous proliferation of infected cells in vitro is mediated by autocrine receptor activation. Images PMID:3133661

  18. Genotoxic evaluation of terbinafine in human lymphocytes in vitro.

    Science.gov (United States)

    Tolomeotti, Danielle; de Castro-Prado, Marialba Avezum Alves; de Sant'Anna, Juliane Rocha; Martins, Ana Beatriz Tozzo; Della-Rosa, Valter Augusto

    2015-01-01

    Terbinafine is an antimycotic drug usually used against several superficial fungal infections and with a potential application in the treatment of human cancers. Since to date there are few data on the genotoxic effects of terbinafine in mammalian cells, current study evaluated the potential genotoxic of such antifungal agent in cultured human peripheral blood lymphocytes. Terbinafine was used at the peak plasma concentration (1.0 μg/ml) and in four additional concentrations higher than the human plasmatic peak (5.0 μg/ml, 25.0 μg/ml, 50.0 μg/ml and 100.0 μg/ml). Chromosomal aberrations (CA), sister chromatid exchanges (SCE), micronuclei (MN), nucleoplasmic bridges (NP) and nuclear buds (NB) were scored as genetic endpoints. In all analysis no significant differences (α = 0.05, Kruskal-Wallis test) were observed. Complementary criterion adopted to obtain the final response in cytogenetic agreed with statistical results. Therefore, results of this study showed that terbinafine neither induced CA, SCE, MN, NP and NB nor affected significantly mitotic, replication and cytokinesis-block proliferation indices in any of the tested concentrations. It may be assumed that terbinafine was not genotoxic or cytotoxic to cultured human peripheral blood lymphocytes in our experimental conditions.

  19. Suppression of lymphocyte proliferation by marijuana components is related to cell number and cell source

    International Nuclear Information System (INIS)

    Klein, T.; Pross, S.; Newton, C.; Friedman, H.

    1986-01-01

    Conflicting reports have appeared concerning the effect of marijuana components on immune responsiveness. The authors have observed that the effect of cannabinoids on lymphocyte proliferation varied with both the concentration of the drug and the mitogen used. They now report that at a constant concentration of drug, the cannabinoid effect varied from no effect to suppression depending upon the number of cells in culture and the organ source of the cells. Dispersed cell suspensions of mouse lymph node, spleen, and thymus were prepared and cultured at varying cell numbers with either delta-9-tetrahydrocannabinol or 11-hydroxy-delta-9-tetrahydrocannabinol and various mitogens. Lymphocyte proliferation was analyzed by 3 H-thymidine incorporation. T-lymphocyte mitogen responses in cultures containing high cell numbers were unaffected by the cannabinoids but as cell numbers were reduced a suppression of the response was observed. Furthermore, thymus cells were considerably more susceptible to cannabinoid suppression than cells from either lymph node or spleen. These results suggest that certain lymphocyte subpopulations are more sensitive to cannabinoid suppression and that in addition to drug concentration other variables such as cell number and cell source must be considered when analyzing cannabinoid effects

  20. SU-G-BRA-16: Target Dose Comparison for Dynamic MLC Tracking and Mid- Ventilation Planning in Lung Radiotherapy Subject to Intrafractional Baseline Drifts

    Energy Technology Data Exchange (ETDEWEB)

    Menten, MJ; Fast, MF; Nill, S; Oelfke, U [Joint Department of Physics at The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London (United Kingdom)

    2016-06-15

    Purpose: Lung tumor motion during radiotherapy can be accounted for by expanded treatment margins, for example using a mid-ventilation planning approach, or by localizing the tumor in real-time and adapting the treatment beam with multileaf collimator (MLC) tracking. This study evaluates the effect of intrafractional changes in the average tumor position (baseline drifts) on these two treatment techniques. Methods: Lung stereotactic treatment plans (9-beam IMRT, 54Gy/3 fractions, mean treatment time: 9.63min) were generated for three patients: either for delivery with MLC tracking (isotropic GTV-to-PTV margin: 2.6mm) or planned with a mid-ventilation approach and delivered without online motion compensation (GTV-to-PTV margin: 4.4-6.3mm). Delivery to a breathing patient was simulated using DynaTrack, our in-house tracking and delivery software. Baseline drifts in cranial and posterior direction were simulated at a rate of 0.5, 1.0 or 1.5mm/min. For dose reconstruction, the corresponding 4DCT phase was selected for each time point of the delivery. Baseline drifts were accounted for by rigidly shifting the CT to ensure correct relative beam-to-target positioning. Afterwards, the doses delivered to each 4DCT phase were accumulated deformably on the mid-ventilation phase using research RayStation v4.6 and dose coverage of the GTV was evaluated. Results: When using the mid-ventilation planning approach, dose coverage of the tumor deteriorated substantially in the presence of baseline drifts. The reduction in D98% coverage of the GTV in a single fraction ranged from 0.4-1.2, 0.6-3.3 and 4.5-6.2Gy, respectively, for the different drift rates. With MLC tracking the GTV D98% coverage remained unchanged (+/− 0.1Gy) regardless of drift. Conclusion: Intrafractional baseline drifts reduce the tumor dose in treatments based on mid-ventilation planning. In rare, large target baseline drifts tumor dose coverage may drop below the prescription, potentially affecting clinical

  1. General Information about Chronic Lymphocytic Leukemia

    Science.gov (United States)

    ... of the lymph system . Having relatives who are Russian Jews or Eastern European Jews. Signs and symptoms ... information about clinical trials is also available. To Learn More About Chronic Lymphocytic Leukemia For more information ...

  2. Leukemia -- Chronic T-Cell Lymphocytic

    Science.gov (United States)

    ... social workers, and patient advocates. Cancer.Net Guide Leukemia - Chronic T-Cell Lymphocytic Introduction Statistics Risk Factors Symptoms and Signs Diagnosis Stages Treatment Options About Clinical Trials Latest Research ...

  3. Neutrophil Lymphocyte Ratio Predicts Postoperative Pain after ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... between preoperatively measured neutrophil-lymphocyte ratio (NLR) – as an inflammation ... analgesic (tenoxicam – as the first drug of choice, paracetamol, tramadol, or pethidine) usage ... fracture fixation). Age, sex, type of ...

  4. Cellular immune therapy for chronic lymphocytic leukemia

    NARCIS (Netherlands)

    Kater, Arnon P.; van Oers, Marinus H. J.; Kipps, Thomas J.

    2007-01-01

    Although chemotherapy can induce complete responses in patients with chronic lymphocytic leukemia (CLL), it is not considered curative. Treated patients generally develop recurrent disease requiring additional therapy, which can cause worsening immune dysfunction, myelosuppression, and selection for

  5. Lymphocyte mobilization by dextran sulfate in beagles

    International Nuclear Information System (INIS)

    Ragan, H.A.; Debban, K.H.

    1978-01-01

    Dogs manifesting 239 Pu-induced lymphopenia responded to the lymphocyte-mobilizing agent, dextran sulfate, to a degree similar to that observed in control dogs. No life-threatening increase in prothrombin times or hemorrhagic tendencies were observed

  6. Chronic Lymphocytic Leukemia: Current Concepts.

    Science.gov (United States)

    Yu, Eun-Mi; Kittai, Adam; Tabbara, Imad A

    2015-10-01

    Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in adults, and while in early, asymptomatic stages treatment is not indicated, the threat to the quality of life and increased mortality of patients posed by more advanced-stage disease necessitate therapeutic intervention. Guidelines of when and how to treat are not well-established because CLL is a disease of the elderly and it is important to balance preservation of functional status and control of the disease. Advances in molecular and genetic profiling has led to the ability to identify sub-groups of patients with CLL whose disease may respond to selected therapy. This review discusses current standard therapies in the major sub-groups of CLL based on age and functional status, in both the front-line and relapsed/refractory settings. It also provides a concise review of novel agents that have shown considerable efficacy in CLL. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  7. How T lymphocytes see antigen

    Science.gov (United States)

    Chakraborty, Arup K.

    2009-03-01

    Complex organisms, like humans, have an adaptive immune system that enables us to do battle with diverse pathogens. This flexible system can also go awry, and many diseases are the direct consequence of the adaptive immune system failing to discriminate between markers of self and non-self. The orchestrators of adaptive immunity are a class of cells called T lymphocytes (T cells). T cells recognize minute numbers of molecular signatures of pathogens, and T cell recognition of these molecular markers of non-self is both specific and degenerate. The specific (yet, cross-reactive), diverse, and self-tolerant T cell repertoire is designed in the thymus. I will describe how an approach that brings together theoretical and computational studies (rooted in statistical physics) with experiments (carried out by key collaborators) has allowed us to shed light on the mechanistic principles underlying how T cells respond to pathogens in a digital fashion (``on'' or ``off''), and how this molecular machinery coupled with frustration (a la spin glasses) plays a key role in designing the special properties of the T cell repertoire during development in the thymus.

  8. Lymphocytic hypophysitis and hypothalamitis - a case report

    International Nuclear Information System (INIS)

    Stelmachowska, M.; Bolko, P.; Wasko, R.; Sowinski, J.; Kosinski, D.; Towpik, I.

    2006-01-01

    Lymphocytic hypophysitis is an unusual disorder that nearly exclusively affects women. We present a case of 69 year-old female patient who developed the symptoms of diabetes insipidus and partial insufficiency of the anterior pituitary gland. Magnetic resonance imaging of the brain revealed a mass involving the sella and suprasellar region. After exclusion of other causes of infiltrate in this region and due to evident reaction to glucocorticoid treatment the diagnosis of lymphocytic hypophisitis and hypothalamitis was established. (author)

  9. SHARPIN Regulates Uropod Detachment in Migrating Lymphocytes

    Directory of Open Access Journals (Sweden)

    Jeroen Pouwels

    2013-11-01

    Full Text Available SHARPIN-deficient mice display a multiorgan chronic inflammatory phenotype suggestive of altered leukocyte migration. We therefore studied the role of SHARPIN in lymphocyte adhesion, polarization, and migration. We found that SHARPIN localizes to the trailing edges (uropods of both mouse and human chemokine-activated lymphocytes migrating on intercellular adhesion molecule-1 (ICAM-1, which is one of the major endothelial ligands for migrating leukocytes. SHARPIN-deficient cells adhere better to ICAM-1 and show highly elongated tails when migrating. The increased tail lifetime in SHARPIN-deficient lymphocytes decreases the migration velocity. The adhesion, migration, and uropod defects in SHARPIN-deficient lymphocytes were rescued by reintroducing SHARPIN into the cells. Mechanistically, we show that SHARPIN interacts directly with lymphocyte-function-associated antigen-1 (LFA-1, a leukocyte counterreceptor for ICAM-1, and inhibits the expression of intermediate and high-affinity forms of LFA-1. Thus, SHARPIN controls lymphocyte migration by endogenously maintaining LFA-1 inactive to allow adjustable detachment of the uropods in polarized cells.

  10. DNA repair and U.V.-light sensitivity of the lymphocytes in discoid lupus erythematosus

    International Nuclear Information System (INIS)

    Horkay, I.; Nagy, E.; Tamasi, P.; Szabo, M.; Csongor, J.

    1975-01-01

    Excision repair and cell damage induced by U.V.-light were studied in peripheral lymphocyte cultures derived from patients with discoid lupus erythematosus. Radioactivity was measured by means of a Packard liquid-scintillation counter, cell damage after U.V.-irradiation was estimated by vital staining with trypan-blue and by decrease of the cell-count. Repair incorporation of mostly normal rate could be demonstrated in the lymphocyte cultures of all the 22 patients with discoid lupus erythematosus. The cell damaging effect of U.V.-light was more increased in these cultures than in those of the normal controls. The repair inhibiting effect of chloroquine administered orally in therapeutic doses to the patients was generally slight and incidental. The possible correlation of the findings is discussed

  11. In vitro immunomodulatory potential of Artemisia indica Willd. in chicken lymphocytes

    Directory of Open Access Journals (Sweden)

    Pushpa Ruwali

    2018-01-01

    Full Text Available Aim: Evaluation of the in vitro immunomodulatory potential of Artemisia indica Willd. methanolic extract in chicken lymphocyte culture system through lymphocyte (B and T cells proliferation assay, after standardizing the maximum non-cytotoxic dose (MNCD in chicken lymphocytes. Materials and Methods: Fresh aerial parts of A. indica Willd. (family: Asteraceae specimens were collected (altitude 1560 m, gotten authenticated, processed, dried, and Soxhlet extracted to yield methanolic extract (AME. Chicken splenocytes were isolated from spleens collected from healthy birds; lymphocytes were separated by density gradient centrifugation, percentage cell viability determined and final cell count adjusted to 107 cells/ml in RPMI-1640 medium. MNCD of AME in chicken lymphocytes was determined through 3-(4,5-dimethylthiazol-2-y1-2,5-diphenyltetrazolium bromide dye reduction assay. Immunomodulatory potential of AME was evaluated through lymphocytes proliferation or B and T cells blastogenesis assay in the presence of appropriate mitogens, namely, lipopolysaccharide (LPS and concanavalin A (Con A, respectively. Results: Maximum concentration of AME exhibiting 100% cell viability (MNCD was 200 μg/ml and was selected for further in vitro analysis. The in vitro exposure of chicken lymphocytes to 200 μg/ml dose of AME, resulted in significant (p<0.05 upregulation of 11.76% in B cell proliferation in the presence of B cell mitogen (LPS and a significant (p<0.05 increase of 12.018% T cells proliferation in the presence of the mitogen (Con A, as compared to the control. Conclusion: The significant upregulation in the proliferation of two major cell types modulating the immune system is an indication of the immunostimulatory potential of the plant. It would be worthwhile to further evaluate A. indica on relevant immunomodulatory aspects, especially the in vivo studies in a poultry system.

  12. Investigation of micronuclei induction in human peripheral blood lymphocytes exposed in vitro to EMF RF

    International Nuclear Information System (INIS)

    Kolomiets, Irina A.; Triapitsina, Galina A.; Polevik, Nikolai D.; Pryakhin, Evgeny A.

    2008-01-01

    Full text: The widespread application of cellular phones is of great concern in view possible consequences for human health. The aim of this study is to assess the capability of electromagnetic fields (EMF) RF with frequency 925 MHz and modulation 217 Hz to induce genotoxic effects as evaluated by the in vitro micronucleus assay on peripheral blood lymphocytes. The flasks of peripheral blood samples collected from healthy volunteers (5 men and 5 women) were placed just on the oscillator of emitting antenna. The signals were produced by the laboratory research plant and were evaluated at four specific absorption rates (SARs) - 0; 0.29; 1.2; 8.1 W/kg. SARs were determined by the calorimetric method. Phytohaemagglutinin stimulated lymphocytes were exposed three times for 10 minutes in the G o (the first 30 minutes after the beginning of cultivation), S (24 hours later), G 2 -M (after 48 hours from the beginning of cultivation) stages of the cell cycle. 72-hours cultures of lymphocytes were examined to determine the extent of micronuclei. The Mann-Whitney U-test was used to evaluate the significance for comparison. The data indicated a significant increase of micronuclei in human lymphocytes exposed to EMF RF (6.5 ± 0.51 0/00; 7.1 ± 0.66 0/00; 7.0 ± 0.50 0/00) in comparison with sham-exposed lymphocytes (3.0 ± 0.60 0/00). There was not revealed a dose-dependent increase of micronuclei in human lymphocytes. It was suggested that the increase of micronuclei in lymphocytes is explicated by a particularity of EMF RF just near the oscillator of emitting antenna. (author)

  13. In vitro immunomodulatory potential of Artemisia indica Willd. in chicken lymphocytes.

    Science.gov (United States)

    Ruwali, Pushpa; Ambwani, Tanuj Kumar; Gautam, Pankaj

    2018-01-01

    Evaluation of the in vitro immunomodulatory potential of Artemisia indica Willd. methanolic extract in chicken lymphocyte culture system through lymphocyte (B and T cells) proliferation assay, after standardizing the maximum non-cytotoxic dose (MNCD) in chicken lymphocytes. Fresh aerial parts of A. indica Willd. (family: Asteraceae) specimens were collected (altitude 1560 m), gotten authenticated, processed, dried, and Soxhlet extracted to yield methanolic extract (AME). Chicken splenocytes were isolated from spleens collected from healthy birds; lymphocytes were separated by density gradient centrifugation, percentage cell viability determined and final cell count adjusted to 10 7 cells/ml in RPMI-1640 medium. MNCD of AME in chicken lymphocytes was determined through 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide dye reduction assay. Immunomodulatory potential of AME was evaluated through lymphocytes proliferation or B and T cells blastogenesis assay in the presence of appropriate mitogens, namely, lipopolysaccharide (LPS) and concanavalin A (Con A), respectively. Maximum concentration of AME exhibiting 100% cell viability (MNCD) was 200 μg/ml and was selected for further in vitro analysis. The in vitro exposure of chicken lymphocytes to 200 µg/ml dose of AME, resulted in significant (p<0.05) upregulation of 11.76% in B cell proliferation in the presence of B cell mitogen (LPS) and a significant (p<0.05) increase of 12.018% T cells proliferation in the presence of the mitogen (Con A), as compared to the control. The significant upregulation in the proliferation of two major cell types modulating the immune system is an indication of the immunostimulatory potential of the plant. It would be worthwhile to further evaluate A. indica on relevant immunomodulatory aspects, especially the in vivo studies in a poultry system.

  14. A microculture system for the measurement of antigen-induced murine lymphocyte proliferation: advantages of 5% horse serum and 5 X 10(-5) M mercaptoethanol.

    Science.gov (United States)

    Brummer, E; Vris, T W; Lawrence, H S

    1977-01-01

    Short term microculture systems which measure murine lymphocyte proliferative responses to mitogens are well established. We demonstrate here that these microculture methods are not suitable for antigen-induced responses because of the high levels of murine lymphocyte proliferation in control cultures associated with the use of fetal calf serum or human serum. We also show that this problem can be eliminated with the use of a combination of 5% horse serum and 5 X 10(-5) M mercaptoethanol. We describe an antigen-induced murine lymphocyte proliferation microculture system in which good stimulation indices are achieved and the lymphocyte proliferation in control cultures remain at a low level throughout the 7 day culture period.

  15. B and T lymphocytes in man. I. Effect of infant thymic irradiation on the circulating B and T lymphocytes

    International Nuclear Information System (INIS)

    Reddy, M.M.; Goh, K.; Hempelmann, L.H.

    1976-01-01

    B and T lymphocytes were studied in a group of adults whose thymic glands were irradiated in infancy for alleged thymic enlargement. Two independent methods were used to determine the B and T lymphocytes from each peripheral blood specimen: (1) the relative proportion of cells with surface immunoglobulins (B lymphocytes) and cells forming rosettes with sheep erythrocytes (T lymphocytes); and (2) the relative mitogenic response to phytohemagglutinin (T lymphocytes) and to pokeweed mitogen (B lymphocytes). All specimens were coded. The results obtained indicate: (1) a reduction of B and T lymphocytes; and (2) a decreased mitogenic response of lymphocytes to phytohemagglutinin and pokeweed mitogen in this group of patients as compared with the controls. These observations suggest that (1) the effect of irradiation to the thymus gland on lymphocytes is long lasting and (2) both B and T lymphocytes are affected by irradiation to the thymus gland

  16. Involvement of the lysophosphatidic acid-generating enzyme autotaxin in lymphocyte-endothelial cell interactions.

    Science.gov (United States)

    Nakasaki, Tae; Tanaka, Toshiyuki; Okudaira, Shinichi; Hirosawa, Michi; Umemoto, Eiji; Otani, Kazuhiro; Jin, Soojung; Bai, Zhongbin; Hayasaka, Haruko; Fukui, Yoshinori; Aozasa, Katsuyuki; Fujita, Naoya; Tsuruo, Takashi; Ozono, Keiichi; Aoki, Junken; Miyasaka, Masayuki

    2008-11-01

    Autotaxin (ATX) is a secreted protein with lysophospholipase D activity that generates lysophosphatidic acid (LPA) from lysophosphatidylcholine. Here we report that functional ATX is selectively expressed in high endothelial venules (HEVs) of both lymph nodes and Peyer's patches. ATX expression was developmentally regulated and coincided with lymphocyte recruitment to the lymph nodes. In adults, ATX expression was independent of HEV-expressed chemokines such as CCL21 and CXCL13, innate immunity signals including those via TLR4 or MyD88, and of the extent of lymphocyte trafficking across the HEVs. ATX expression was induced in venules at sites of chronic inflammation. Receptors for the ATX enzyme product LPA were constitutively expressed in HEV endothelial cells (ECs). In vitro, LPA induced strong morphological changes in HEV ECs. Forced ATX expression caused cultured ECs to respond to lysophosphatidylcholine, up-regulating lymphocyte binding to the ECs in a LPA receptor-dependent manner under both static and flow conditions. Although in vivo depletion of circulating ATX did not affect lymphocyte trafficking into the lymph nodes, we surmise, based on the above data, that ATX expressed by HEVs acts on HEVs in situ to facilitate lymphocyte binding to ECs and that ATX in the general circulation does not play a major role in this process. Tissue-specific inactivation of ATX will verify this hypothesis in future studies of its mechanism of action.

  17. Study of the radioprotective effect of flavonoid quercetin on human lymphocytes

    International Nuclear Information System (INIS)

    Siqueira, Williams Nascimento de

    2013-01-01

    Ionizing radiation has been used in various fields of study, as medicine, industry, energy production, surgical materials sterilization, preservation and sterilization of foods, among others. These radiations may be responsible for adverse effects at molecular level in living organisms, where most important damage occurs in deoxyribonucleic acid molecule, DNA. These harmful effects caused by radiation highlights the importance of acquiring knowledge about radioprotector substances because they can act as protector of living tissue of those effects. In this research was investigated the possible radioprotective effect 'in vitro' of the flavonoid quercetin in human lymphocytes exposed to gamma radiation. At first, test was performed to evaluate the antioxidant activity of quercetin by capturing DPPH free radical molecules. Then, it was collected peripheral blood of volunteers donors. Then the samples were irradiated from linear accelerator (Siemens Primus - energy of 6 MeV and dose rate of 200 cGy/min from IMIP-PE). After samples irradiation, lymphocytes were isolated from whole blood and then the culture was carried out to obtain lymphocyte in metaphases and subsequent, analysis of chromosomal abnormalities were done at optical microscope. Statistical analysis was used Student 't' test. The results showed that quercetin at a concentration of 37.5 μM presented radioprotective against damage from gamma radiation on human lymphocytes in vitro. Have been also observed that the irradiated lymphocytes showed morphologically unchanged after undergoing the presence of the flavonoid quercetin. (author)

  18. Radioprotective Effect of Achillea millefolium L Against Genotoxicity Induced by Ionizing Radiation in Human Normal Lymphocytes

    Directory of Open Access Journals (Sweden)

    Somayeh Shahani

    2015-04-01

    Full Text Available The radioprotective effect of Achillea millefolium L (ACM extract was investigated against genotoxicity induced by ionizing radiation (IR in human lymphocytes. Peripheral blood samples were collected from human volunteers and incubated with the methanolic extract of ACM at different concentrations (10, 50, 100, and 200 μg/mL for 2 hours. At each dose point, the whole blood was exposed in vitro to 2.5 Gy of X-ray and then the lymphocytes were cultured with mitogenic stimulation to determine the micronuclei in cytokinesis-blocked binucleated cell. Antioxidant capacity of the extract was determined using free radical-scavenging method. The treatment of lymphocytes with the extract showed a significant decrease in the incidence of micronuclei binucleated cells, as compared with similarly irradiated lymphocytes without any extract treatment. The maximum protection and decrease in frequency of micronuclei were observed at 200 μg/mL of ACM extract which completely protected genotoxicity induced by IR in human lymphocytes. Achillea millefolium extract exhibited concentration-dependent radical-scavenging activity on 1,1-diphenyl-2-picryl hydrazyl free radicals. These data suggest that the methanolic extract of ACM may play an important role in the protection of normal tissues against genetic damage induced by IR.

  19. Sister chromatid exchange induced by X-irradiation of retinoblastoma lymphocytes

    International Nuclear Information System (INIS)

    Abramovsky-Kaplan, I.; Jones, I.S.

    1984-01-01

    Lymphocyte cultures were employed to assess the degree of spontaneous and induced chromosomal fragility in retinoblastoma. Sister chromatid exchange (SCEs) were scored in metaphases. Three unilateral, three bilateral, eleven family members and controls were studied. Retinoblastoma (RB) lymphocytes did not exhibit increased spontaneous fragility. X-irradiation (25-200 rad) did not significantly increase SCE in unilateral retinoblastoma lymphocytes when compared with controls (P greater than 0.50). However, bilaterally affected subjects and three unaffected relatives demonstrated a statistically significant increase in SCE (P less than 0.01). In conclusion, hereditary retinoblastoma lymphocytes appear more radiosensitive than sporadic retinoblastoma, perhaps, reflecting the increased second malignancies in germinal mutation retinoblastoma. In addition, the analysis of radiation-induced SCE in peripheral blood lymphocytes of RB patients and family members may provide a valuable tool increasing the accuracy of genetic counseling for this disorder. Additional studies of RB patients and families are needed to assess the relevance of this approach to genetic counseling

  20. The role of nucleotides in augmentation of lymphocyte locomotion: Adaptional countermeasure development in microgravity analog environments

    Science.gov (United States)

    Sundaresan, Alamelu; Kulkarni, Anil D.; Yamauchi, Keiko; Pellis, Neal R.

    2006-09-01

    Space travel and long-term space residence such as envisaged in the exploration era implicates burdens on the immune system. An optimal immune response is required to countered and with-stand exposure to pathogens. Countermeasure development is an important avenue in space research especially for long-term space exploration. Microgravity exposure causes detrimental effects in lymphocyte functions which may impair immune response. Impaired lymphocyte function can be remedied by bypassing cell membrane events. This is done by using compounds such as Phorbol Myristate Acetate (PMA). Since activation in mouse splenocytes was augmented using nucleotides, it was essential to observe their effects on human lymphocyte locomotion. A nucleotide/nucleoside (NT/NT) mixture from Otsuka Pharmaceuticals (Naruto, Japan) was used at recommended doses. In lymphocytes cultured in modeled microgravity, the NT/NT mixture used orchestrated locomotion recovery by more than 87%, similar to the response documented with PMA in lymphocytes. Both 12µM and 120µM doses worked similarly. These are preliminary results leading to the possible use of the NT/NT mixture to mitigate immune suppression in micro-gravity. More studies in this direction are required to delineate the role of NT/NT on the immune response in microgravity.