Sample records for amethopterin

  1. Meningopatia leucémica em paciente com remissão hematológica tratado com sucesso pelo Amethopterin Intratecal

    Mário Ritter


    Full Text Available É apresentado um caso de meningopatia leucêmica com um quadro de hipertensão intracraniana, que surgiu 18 meses após a remissão clínica e hematológica de leucemia aguda. A terapêutica por via intratecal com o Amethopterin, na dose de 5 mg, repetida 6 vêzes e com intervalos de 5 a 7 dias, proporcionou melhora clínica imediata e normalização do LCR após dois meses de tratamento. O paciente continuou bem clinicamente e com o sangue e o LCR normais após 4 meses de observação. A experiência dêste caso e daqueles citados na literatura justificam que todos os pacientes leucêmicos sejam cuidadosamente observados a fim de se poder diagnosticar precocemente uma complicação neurológica, para que o tratamento adequado possa permitir maior sobrevida. O exame do LCR tem importância decisiva no diagnóstico desta complicação; ulteriormente, os exames seriados do LCR orientam a duração e a intensidade do tratamento. A padronização do tratamento das complicações neurológicas das leucemias constitui campo aberto às investigações.

  2. Experimentally validated novel inhibitors of Helicobacter pylori phosphopantetheine adenylyltransferase discovered by virtual high-throughput screening.

    Chao-Sheng Cheng

    Full Text Available Helicobacter pylori is a major etiologic agent associated with the development and maintenance of human gastritis. The goal of this study was to develop novel antibiotics against H. pylori, and we thus targeted H. pylori phosphopantetheine adenylyltransferase (HpPPAT. PPAT catalyzes the penultimate step in coenzyme A biosynthesis. Its inactivation effectively prevents bacterial viability, making it an attractive target for antibacterial drug discovery. We employed virtual high-throughput screening and the HpPPAT crystal structure to identify compounds in the PubChem database that might act as inhibitors of HpPPAT. d-amethopterin is a potential inhibitor for blocking HpPPAT activity and suppressing H. pylori viability. Following treatment with d-amethopterin, H. pylori exhibited morphological characteristics associated with cell death. d-amethopterin is a mixed inhibitor of HpPPAT activity; it simultaneously occupies the HpPPAT 4'-phosphopantetheine- and ATP-binding sites. Its binding affinity is in the micromolar range, implying that it is sufficiently potent to serve as a lead compound in subsequent drug development. Characterization of the d-amethopterin and HpPPAT interaction network in a docked model will allow us to initiate rational drug optimization to improve the inhibitory efficacy of d-amethopterin. We anticipate that novel, potent, and selective HpPPAT inhibitors will emerge for the treatment of H. pylori infection.

  3. Prevention and Control of Secondary Disease following Allogenic Bone-Marrow Transplantation

    A review is presented of the various methods found to be effective in preventing or ameliorating acute secondary disease in rodents and primates. Selective physical elimination of lymphoid cells by centrifugation over a discontinuous albumin gradient, post-transplantation administration of cyclophosphamide, amethopterin or ALS and the selection of histocompatible bone-marrow donors are considered to be the most promising methods in primares. It is not known to what extent delayed secondary disease will occur in monkeys and man in cases where acute secondary disease has been successfully avoided. (author)

  4. Combination chemotherapy (COMP protocol) and radiotherapy of anaplastic supratentorial gliomas

    Postoperative survival time and recurrence-free intervals in 116 consecutive patients with supratentorial grade III and IV gliomas (glioblastomas, gliosarcomas, anaplastic astrocytomas, and ependymomas) were compared in unselected groups receiving different forms of treatment. Postoperative high-voltage radiotherapy (31 patients, dosage 4,000-6,000 rads) and combined chemotherapy consisting of CCNU, vincristine, amethopterine, and procarbazine in 15-day circles (COMP protocol) (12 patients) showed the same median survival time of 10.6 months and comparable recurrence-free intervals of 6.8 and 7.0 months, respectively. These results were significantly different from a control group (39 patients) receiving best postoperative supportive (conventional) care (median survival 5.4 months, free interval 3.7 months). Combination of postoperative radiotherapy with simultaneous polychemotherapy (COMP protocol), evaluated in 18 patients, did not significantly change the recurrence-free interval (median 7.0 months), but increased the median survival time to 12.9 months, which was significantly superior to the two other treatment groups. The toxic side effects of COMP therapy were moderate and essentially haematological. In general, simultaneous radiation and chemical treatment was well tolerated after major tumour resection. These preliminary results of postoperative combination of radiation and polychemotherapy for anaplastic supratentorial gliomas appear encouraging, but further trials for optimization of combined therapeutic strategies are warranted. (author)

  5. Estimations of the DNA Synthesis Rate of Bone Marrow Cells after Administration of Labelled Thymidine In Vitro

    Bone marrow cells are incubated with labelled thymidine under varying in vitro conditions. The incorporation rate of labelled thymidine into DNA is influenced by the condition and duration of. the in vitro incubation. Similar influences operate on the pool size of labelled thymidine phosphates. Up to concentrations of 10-6 M thymidine in the incubation medium there is a linear relation of thymidine concentration and thymidine incorporation into DNA. Concentrations of thymidine exceeding 10-6 M lead to increasing inhibition of the thymidine kinase. The endogenous formation of thymidylate cannot be inhibited entirely by exogenous thymidine supply. Consequently, determinations of the DNA synthesis rate from the incorporated amount of labelled thymidine have to be corrected for the respective endogenous thymidylate contribution. A better procedure is to block the formation of endogenous thymidylate by means of amethopterin. Standard conditions are described, under which an undisturbed synthesis of DNA thymine from exogenous thymidine only takes place. Determinations can be performed by means of autoradiographic or biochemical techniques. By application of the semi-automatic grain counting technique, after sufficient autoradiographic standardization, evaluations of DNA synthesis rates and DNA synthesis times of different cell types in the bone marrow become practicable. (author)

  6. Adult female of Strongyloides stercoralis in respiratory secretions

    Bava Amadeo Javier Bava; Domnguez Cecilia; Troncoso Alcides


    Objective: To communicate the presence of adult females, rabditoid larvae and eggs of Strongyloides stercoralis (S. stercoralis) in the respiratory secretions obtained by tracheal aspirate from a HIV-negative patient who was suffering from polymyositis, and treated with corticoids and amethopterin and assisted by pneumonia. Methods: The respiratory secretions submitted to the Parasitology Laboratory of the Muñiz Hospital were made more concentrated by centrifugation (1 500 r/min for 15 seconds). Wet mount microscopy was performed with the pellet. Results: It revealed adult females, rabditoid larvae and eggs of S. stercoralis. Further parasitological studies performed after the start of the treatment with ivermectin on fresh fecal samples, gastric lavages and tracheal aspirates showed scanty mobile filariform and rabditoid larvae of the same parasite. Conclusions: The presence of adult female S. stercoralis which has never been observed before in the clinical samples submitted to our Laboratory for investigation can be considered as an indirect marker of the severe immunosupression of the patient.

  7. Effect of temperature on the methotrexate BSA interaction: Spectroscopic study

    Sułkowska, A.; Maciążek, M.; Równicka, J.; Bojko, B.; Pentak, D.; Sułkowski, W. W.


    Rheumatoid arthritis (RA) is an autoimmune and chronic inflammatory illness which affects about one percent of the world's population. Methotrexate (4-amino-10-methylfolic acid) (MTX) also known as amethopterin is commonly used to treat rheumatoid arthritis (RA). It is transported in the circulary system as a complex with serum albumin. The aim of this study was to investigate the interactions of MTX with transporting protein with the use of spectroscopic methods. The binding of MTX to bovine serum albumin (BSA) was studied by monitoring the changes in the emission fluorescence spectra of protein in the presence of MTX at excitation wavelength of 280 nm and 295 nm. The quenching of protein fluorescence at temperature range from 298 K to 316 K was observed. Energy transfer between methotrexate and fluorophores contained in the serum albumin structure was found at the molar ratio MTX:BSA 7.5:1. The relative fluorescence intensity of BSA decreases with increase of temperature. Similar results were observed for BSA excited with 280 nm and 295 nm at the same temperature range. The presence of MTX seems to prevent these changes. Temperature dependence of the binding constant has been presented. The binding and quenching constants for equilibrium complex were calculated using Scatchard and Stern-Volmer method, respectively. The results show that MTX forms π-π complex with aromatic amino acid residues of BSA. The binding site for MTX on BSA was found to be situated in the hydrophobic IIA or IB subdomain where the Trps were located. The spontaneity of MTX-BSA complex formation in the temperature range 298-316 K was ascertained.

  8. Effects and Complications of Bone-Marrow Transplantation in Man

    Full text: Allogenic bone-marrow grafting in 24 human leukaemic subjects is described. The graft failed in 7 cases and took in 17 cases. In the latter group, all 17 cases were complicated by the secondary syndrome which was-fatal in 13 cases and controlled in 4 cases. The immunogenetic and immunological factors determining the establishment and evolution of haematological radiochimeras in man are discussed. The choice of donor is fundamental. Three tests are effective in donor selection, the indirect histocompatibility test, the leucocyte antigen test and the reaction of donor and recipient leucocytes in the dermis of an irradiated hamster. When marrow from several donors is transfused, the recipient spontaneously selects the genetically nearest. It seems likely there is more chance of finding a suitable donor among genetically related subjects than among those who are unrelated. The frequency of graft take seems slightly lower in recipients who have previously received blood transfusions. Total bone-marrow graft is associated with specific tolerance towards donor tissues. This is paralleled by the production in the chimera of immunoglobulins produced by the graft. The secondary syndrome seems, as in animals, to be related essentially to the graft-versus-host reaction. It is convenient to distinguish among its various manifestations, on the one hand, those lesions which are readily controlled such as hepatitis or erythrodermia associated with infiltration and proliferation of immunologically competent cells from the graft and, on the other hand, immune insufficiency with regard to micro-organisms, especially viruses and Candida albicans. This latter group, the mechanism of which is complex, still eludes attempts at preventive and curative control. The use of multiple donors and the administration of cortisone during marrow transfusion and A-methopterin and/or cyclophosphamide in the days following transfusions; seem to have reduced the severity of the secondary