Group normalization for genomic data.

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Mahmoud Ghandi

Full Text Available Data normalization is a crucial preliminary step in analyzing genomic datasets. The goal of normalization is to remove global variation to make readings across different experiments comparable. In addition, most genomic loci have non-uniform sensitivity to any given assay because of variation in local sequence properties. In microarray experiments, this non-uniform sensitivity is due to different DNA hybridization and cross-hybridization efficiencies, known as the probe effect. In this paper we introduce a new scheme, called Group Normalization (GN, to remove both global and local biases in one integrated step, whereby we determine the normalized probe signal by finding a set of reference probes with similar responses. Compared to conventional normalization methods such as Quantile normalization and physically motivated probe effect models, our proposed method is general in the sense that it does not require the assumption that the underlying signal distribution be identical for the treatment and control, and is flexible enough to correct for nonlinear and higher order probe effects. The Group Normalization algorithm is computationally efficient and easy to implement. We also describe a variant of the Group Normalization algorithm, called Cross Normalization, which efficiently amplifies biologically relevant differences between any two genomic datasets.

Application of radioreceptor assay for chorionic gonadotropin in diagnosis of normal and disturbed pregnancy

International Nuclear Information System (INIS)

Koch, R.; Schmidt-Gollwitzer, M.; Nevinny-Stickel, J.

1977-01-01

For diagnoses of normal and disturbed pregnancy, a radioreceptor assay (RRA) for the detection of chorionic gonadotropin (HLG) has been developed. The hormone was labelled with 125 I. Compared with biological and immunological methods, the RRA has a higher sensitivity and a shorter evaluation time. (orig./VJ) [de

Three-dimensional CT features of occipital squama normal anatomy, anatomic variations and fractures

International Nuclear Information System (INIS)

Liu Jungang; Li Xin; Wang Chunxiang; Zhang Lin; Guo Wanhua

2013-01-01

Objective: To evaluate 3D CT features of normal anatomy, anatomic variations and fractures of occipital squama. Methods: The 3D CT features on MIP, VR images were analyzed retrospectively in 589 pediatric cases. The normal anatomy, anatomic variations and fractures of occipital squama were observed respectively, and the differential diagnostic features including the individual location, appearance and extension were analyzed. Results: Four hundred and thirty-three patients (75.2%) showed normal anatomy, including 154 patients with adult occipital anatomical features, 279 patients with posterior intraoccipital synchondrosis, and 37 patients with Kerckring-supraoccipital synchondrosis. When cases with recent trauma history were excluded, 113 patients (19.1%) showed anatomic variants, including unpenetrating sutures and penetrating sutures. The former could be subdivided to Mendosal sutures in 23 cases, superior median fissures in 19 cases, and midline supraoccipital fissures in 4 cases, while the latter could be subdivided to the interparietal bone variations in 54 cases, wormian bones in 23 cases, and accessory bones in 7 cases. Two or more variations coexisted in 33 cases. The occipital squama fractures were shown in 34 cases (5.6%), including linear fractures in 27 cases, comminuted fractures in 3 cases, with depression fracture in one case, separation of cranial sutures in 3 cases, and other fractures associated with variants in 3 cases. The fractures were sharp, or jagged, without limitation of the occification. Conclusion: There are different 3D CT features of normal anatomy, anatomic variations and fractures of occipital squama in children, which are important for making the accurate diagnosis. (authors)

Variation in assessment of oxidatively damaged DNA in mononuclear blood cells by the comet assay with visual scoring

DEFF Research Database (Denmark)

Forchhammer, Lykke; Bräuner, Elvira Vaclavik; Folkmann, Janne Kjaersgaard

2008-01-01

The comet assay is popular for assessments of genotoxicity, but the comparison of results between studies is challenging because of differences in experimental procedures and reports of DNA damage in different units. We investigated the variation of DNA damage in mononuclear blood cells (MNBCs......) measured by the comet assay with focus on the variation related to alkaline unwinding and electrophoresis time, number of cells scored, as well as the putative benefits of transforming the primary end points to common units by the use of reference standards and calibration curves. Eight experienced......, our results indicate that inter-investigator difference in scoring is a strong determinant of DNA damage levels measured by the comet assay....

In normal human fibroblasts variation in DSB repair capacity cannot be ascribed to radiation-induced changes in the localisation, expression or activity of major NHEJ proteins

DEFF Research Database (Denmark)

Kasten-Pisula, Ulla; Vronskaja, Svetlana; Overgaard, Jens

2008-01-01

in the activity of the DNA-PK complex induced upon irradiation. CONCLUSIONS: For normal human fibroblasts, the level or activity of NHEJ proteins measured prior to or after irradiation cannot be used to predict the DSB repair capacity or cellular radiosensitivity. Udgivelsesdato: 2008-Mar......BACKGROUND AND PURPOSE: The aim of the present study was to test whether for normal human fibroblasts the variation in double-strand break (DSB) repair capacity results from radiation-induced differences in localisation, expression or activity of major non-homologous end-joining (NHEJ) proteins....... MATERIALS AND METHODS: Experiments were performed with 11 normal human fibroblast strains AF01-11. NHEJ proteins were determined by Western blot and DNA-PK activity by pulldown-assay. RESULTS: The four NHEJ proteins tested (Ku70, Ku80, XRCC4 and DNA-PKcs) were found to be localised almost exclusively...

Assay based on electrical impedance spectroscopy to discriminate between normal and cancerous mammalian cells

Science.gov (United States)

Giana, Fabián Eduardo; Bonetto, Fabián José; Bellotti, Mariela Inés

2018-03-01

In this work we present an assay to discriminate between normal and cancerous cells. The method is based on the measurement of electrical impedance spectra of in vitro cell cultures. We developed a protocol consisting on four consecutive measurement phases, each of them designed to obtain different information about the cell cultures. Through the analysis of the measured data, 26 characteristic features were obtained for both cell types. From the complete set of features, we selected the most relevant in terms of their discriminant capacity by means of conventional statistical tests. A linear discriminant analysis was then carried out on the selected features, allowing the classification of the samples in normal or cancerous with 4.5% of false positives and no false negatives.

Comparison of the circadian variation in cell proliferation in normal and neoplastic colonic epithelial cells.

Science.gov (United States)

Kennedy, M F; Tutton, P J; Barkla, D H

1985-09-15

Circadian variations in cell proliferation in normal tissues have been recognised for many years but comparable phenomena in neoplastic tissues appear not to have been reported. Adenomas and carcinomas were induced in mouse colon by injection of dimethylhydrazine (DMH) and cell proliferation in these tumors was measured stathmokinetically. In normal intestine cell proliferation is fastest at night whereas in both adenomas and carcinomas it was found to be slower at night than in the middle of the day. Chemical sympathectomy was found to abolish the circadian variation in tumor cell proliferation.

On the efficient simulation of the left-tail of the sum of correlated log-normal variates

KAUST Repository

Alouini, Mohamed-Slim

2018-04-04

The sum of log-normal variates is encountered in many challenging applications such as performance analysis of wireless communication systems and financial engineering. Several approximation methods have been reported in the literature. However, these methods are not accurate in the tail regions. These regions are of primordial interest as small probability values have to be evaluated with high precision. Variance reduction techniques are known to yield accurate, yet efficient, estimates of small probability values. Most of the existing approaches have focused on estimating the right-tail of the sum of log-normal random variables (RVs). Here, we instead consider the left-tail of the sum of correlated log-normal variates with Gaussian copula, under a mild assumption on the covariance matrix. We propose an estimator combining an existing mean-shifting importance sampling approach with a control variate technique. This estimator has an asymptotically vanishing relative error, which represents a major finding in the context of the left-tail simulation of the sum of log-normal RVs. Finally, we perform simulations to evaluate the performances of the proposed estimator in comparison with existing ones.

Enzyme-linked immunosorbent assay characterization of Basal variation and heritability of systemic microfibrillar-associated protein 4

DEFF Research Database (Denmark)

Sækmose, Susanne Gjørup; Schlosser, Anders; Holst, René

2013-01-01

Microfibrillar-associated protein 4 (MFAP4) is a systemic biomarker that is significantly elevated in samples from patients suffering from hepatic cirrhosis. The protein is generally localized to elastic fibers and other connective tissue fibers in the extracellular matrix (ECM), and variation...... in systemic MFAP4 (sMFAP4) has the potential to reflect diverse diseases with increased ECM turnover. Here, we aimed to validate an enzyme-linked immunosorbent assay (ELISA) for the measurement of sMFAP4 with an emphasis on the robustness of the assay. Moreover, we aimed to determine confounders influencing...

Comparison of third and second generation parathyroid hormone assays and their use in chronic hemdialysis patients

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Alexis Muryan

2017-06-01

Full Text Available Introduction: This work’s objective is to compare third and second generation assays in patients with normal kidney function and in chronic hemodialysis patients, and the implications on the latter. Methods: 60 chronic hemodialysis patients and 40 patients with normal kidney function were studied and their PTH levels were measured for both assays. Results: In patients population with normal kidney function the average on PTH was 51.8 and 45.6 pg/ml with second and third generation assays respectively. In chronic hemodialysis patients the average PTH was 193.9 and 137.1 pg/ml with second and third generation assays respectively. The difference between assays was 11.3% and 29.3% in patients with normal kidney function and in hemodialysis patients respectively. Third generation assay caused a variation in the amount of patients that fall over seve ral PTH ranges according to KDIGO guidelines, for a lesser value of 2 times the reference upper limit: it changes from 20 to 25 patients, between 2 and 9 times: it changes from 31 to 32 patients, and more than 9 times: it changes from 9 to 3 patients. Conclusions: When PTH concentration increases the difference between both assays also increases, for this reason we cannot use them indiscriminately in a chronic hemodialysis patient population. With third generation assays 11 patients (18.3% changed their classification according to KDIGO guidelines, which will result in a change of treatment.

Multidimensional Normalization to Minimize Plate Effects of Suspension Bead Array Data.

Science.gov (United States)

Hong, Mun-Gwan; Lee, Woojoo; Nilsson, Peter; Pawitan, Yudi; Schwenk, Jochen M

2016-10-07

Enhanced by the growing number of biobanks, biomarker studies can now be performed with reasonable statistical power by using large sets of samples. Antibody-based proteomics by means of suspension bead arrays offers one attractive approach to analyze serum, plasma, or CSF samples for such studies in microtiter plates. To expand measurements beyond single batches, with either 96 or 384 samples per plate, suitable normalization methods are required to minimize the variation between plates. Here we propose two normalization approaches utilizing MA coordinates. The multidimensional MA (multi-MA) and MA-loess both consider all samples of a microtiter plate per suspension bead array assay and thus do not require any external reference samples. We demonstrate the performance of the two MA normalization methods with data obtained from the analysis of 384 samples including both serum and plasma. Samples were randomized across 96-well sample plates, processed, and analyzed in assay plates, respectively. Using principal component analysis (PCA), we could show that plate-wise clusters found in the first two components were eliminated by multi-MA normalization as compared with other normalization methods. Furthermore, we studied the correlation profiles between random pairs of antibodies and found that both MA normalization methods substantially reduced the inflated correlation introduced by plate effects. Normalization approaches using multi-MA and MA-loess minimized batch effects arising from the analysis of several assay plates with antibody suspension bead arrays. In a simulated biomarker study, multi-MA restored associations lost due to plate effects. Our normalization approaches, which are available as R package MDimNormn, could also be useful in studies using other types of high-throughput assay data.

Contribution of Myostatin gene polymorphisms to normal variation in lean mass, fat mass and peak BMD in Chinese male offspring

Institute of Scientific and Technical Information of China (English)

Hua YUE; Miao LI; Yu-juan LIU; Song-hua WU; Zhen-lin ZHANG; Jin-wei HE; Hao ZHANG; Chun WANG; Wei-wei HU; Jie-mei GU; Yao-hua KE; Wen-zhen FU; Yun-qiu HU

2012-01-01

Myostatin gene is a member of the transforming growth factor-β (TGF-β) family that negatively regulates skeletal muscle growth.Genetic polymorphisms in Myostatin were found to be associated with the peak bone mineral density (BMD) in Chinese women.The purpose of this study was to investigate whether Myostatin played a role in the normal variation in peak BMD,lean mass (LM),and fat mass (FM) of Chinese men.Methods:Four hundred male-offspring nuclear families of Chinese Han ethnic group were recruited.Anthropometric measurements,includingthe peak BMD,body LM and FM were measured using dual-energy X-ray absorptiometry (DXA).The single nucleotide polymorphisms (SNPs) studied were tag-SNPs selected by sequencing.Both rs2293284 and +2278G＞A were genotyped using TaqMan assay,and rs3791783 was genotyped with PCR-restriction fragment length polymorphism (RFLP) analysis.The associations of the SNPs with anthropometfic variations were analyzed using the quantitative transmission disequilibrium test (QTDT).Results:Using QTDT to detect within-family associations,neither single SNP nor haplotype was found to be associated with peak BMD at any bone site.However,rs3791783 was found to be significantly associated with fat mass of the trunk (P＜0.001).Moreover,for within-family associations,haplotypes AGG,AAA,and TGG were found to be significantly associated with the trunk fat mass (all P＜0.001).Conclusion:Our results suggest that genetic variation within Myostatin may play a role in regulating the variation in fat mass in Chinese males.Additionally,the Myostatin gene may be a candidate that determines body fat mass in Chinese men.

Multi-center clinical evaluation of the Access AMH assay to determine AMH levels in reproductive age women during normal menstrual cycles.

Science.gov (United States)

Gracia, Clarisa R; Shin, Sanghyuk S; Prewitt, Maureen; Chamberlin, Janna S; Lofaro, Lori R; Jones, Kristin L; Clendenin, Marta; Manzanera, Katherine E; Broyles, Dennis L

2018-03-14

AMH is widely used for assessing ovarian reserve, and it is particularly convenient, because it is thought to have minimal variability throughout the menstrual cycle. However, studies assessing the stability of AMH over the menstrual cycle have been conflicting. The purpose of this study is to determine whether AMH levels vary across the normal menstrual cycle. A multi-center, prospective cohort study conducted at three US centers. Fifty females with regular menstrual cycles aged 18-45 underwent serial venipuncture every 3-5 days starting in the early follicular phase and lasting up to 10 collections. AMH was tested using the Access 2 immunoassay system. Age-adjusted mixed-effect models utilizing data from 384 samples from 50 subjects demonstrated a within subject standard deviation of 0.81 (95% CI 0.75-0.88) with a coefficient of variation of 23.8% across the menstrual cycle and between subject standard deviation of 2.56 (95% CI 2.13-3.21) with a coefficient of variation of 75.1%. Intra-class correlation (ICC) of AMH across the menstrual cycle was 0.91. Overall, AMH levels, using the automated Access AMH assay, appear to be relatively stable across the menstrual cycle. Fluctuations, if any, appear to be small, and therefore, clinicians may advise patients to have AMH levels drawn at any time in the cycle.

Enzyme-linked immunosorbent assay characterization of basal variation and heritability of systemic microfibrillar-associated protein 4.

Directory of Open Access Journals (Sweden)

Susanne Gjørup Sækmose

Full Text Available BACKGROUND: Microfibrillar-associated protein 4 (MFAP4 is a systemic biomarker that is significantly elevated in samples from patients suffering from hepatic cirrhosis. The protein is generally localized to elastic fibers and other connective tissue fibers in the extracellular matrix (ECM, and variation in systemic MFAP4 (sMFAP4 has the potential to reflect diverse diseases with increased ECM turnover. Here, we aimed to validate an enzyme-linked immunosorbent assay (ELISA for the measurement of sMFAP4 with an emphasis on the robustness of the assay. Moreover, we aimed to determine confounders influencing the basal sMFAP4 variability and the genetic contribution to the basal variation. METHODS: The sandwich ELISA was based on two monoclonal anti-MFAP4 antibodies and was optimized and calibrated with a standard of recombinant MFAP4. The importance of pre-analytical sample handling was evaluated regarding sample tube type, time, and temperature conditions. The mean value structure and variance structure was determined in a twin cohort including 1,417 Danish twins (age 18-67 years by mixed-effect linear regression modeling. RESULTS: The practical working range of the sandwich ELISA was estimated to be 4-75 U/ml. The maximum intra- and inter-assay variation was estimated to be 8.7% and 6.6%, respectively. Sample handling and processing appeared to influence MFAP4 measurements only marginally. The average concentration of sMFAP4 in the serum was 18.9 ± 8.4 (SD U/ml in the twin cohort (95% CI: 18.5-19.4, median sMFAP4 17.3 U/ml. The mean structure model was demonstrated to include waist-hip ratio, age, and cigarette smoking status in interactions with gender. A relatively low heritability of h(2 = 0.24 was found after applying a model including additive genetic factors and shared and non-shared environmental factors. CONCLUSIONS: The described ELISA provides robust measures of the liver fibrosis marker sMFAP4. The low heritability and the relatively

Normal variation of right gastric artery origin on abdominal angiogram

International Nuclear Information System (INIS)

Kim, Hyoung Seuk; Kim, Yun Hwan

1997-01-01

To evaluate the normal variations in the origin of the right gastric artery(RGA), as seen on abdominal angiogram. Four hundred and twenty-six patients underwent celiac and superior mesenteric arteriogram, and in 154, the origin of the RGA was identified (M:F=3D116:38;mean age, 56 years;range, 6-84 years). Digital subtraction angiography were performed in 101 patients, and conventional angiography in 53;we thus evaluated the origin of the RGA, normal variation of the hepatic artery, and the relationship between them. The origin of the RGA was the proper hepatic artery(PHA) in 43% of cases(n=3D67), the left hepatic artery(LHA) in 41%(n=3D63), the common hepatic artery(CHA) in 9%(n=3D14), the right hepatic artery(RHA) in 4%(n=3D6), and the gastroduodenal artery(GDA) in 3%(n=3D4). Of these 154 patients, 126(82%) showed a normal hepatic artery branching pattern, with both hepatic arteries arising from the PHA;in 18 patients(12%), the RHA arose from the superior mesenteric artery (SMA), and in 6 patients(4%), the LHA arose from the left gastric artery(LGA). In 4 patients(3%), other branching patterns of the hepatic artery were noted. In 16 of 18 patients(89%) whose RHA arose from the SMA, the RGA originated in the LHA;in the other two, the RGA arose from the GDA and CHA, respectively. In 43% of cases, the main site from which the GRA originated was the PHA, and in 41%, the LHA, as seen on abdominal angiogram. Where the RHA arose from the SMA, its most frequent site of origin, seen in 89% of cases, was the LHA. The exact recognition of the origin of the RGA, as seen on abdominal angiogram, could lead to a reduction of transarterial chemoembolization-related gastric complications.=20

Reporter gene assay for the quantification of the activity and neutralizing antibody response to TNFα antagonists

DEFF Research Database (Denmark)

Lallemand, Christophe; Kavrochorianou, Nadia; Steenholdt, Casper

2011-01-01

A cell-based assay has been developed for the quantification of the activity of TNFα antagonists based on human erythroleukemic K562 cells transfected with a NFκB regulated firefly luciferase reporter-gene construct. Both drug activity and anti-drug neutralizing antibodies can be quantified...... with a high degree of precision within 2h, and without interference from cytokines and other factors known to activate NFκB. The assay cells also contain the Renilla luciferase reporter gene under the control of a constitutive promoter that allows TNFα-induced firefly luciferase activity to be normalized...... relative to Renilla luciferase expression. Thus, results are independent of cell number or differences in cell viability, resulting in intra and inter assay coefficients of variation of 10% or less. Normalization of results relative to the expression of an internal standard also provides a means...

Validation of the Filovirus Plaque Assay for Use in Preclinical Studies

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Amy C. Shurtleff

2016-04-01

Full Text Available A plaque assay for quantitating filoviruses in virus stocks, prepared viral challenge inocula and samples from research animals has recently been fully characterized and standardized for use across multiple institutions performing Biosafety Level 4 (BSL-4 studies. After standardization studies were completed, Good Laboratory Practices (GLP-compliant plaque assay method validation studies to demonstrate suitability for reliable and reproducible measurement of the Marburg Virus Angola (MARV variant and Ebola Virus Kikwit (EBOV variant commenced at the United States Army Medical Research Institute of Infectious Diseases (USAMRIID. The validation parameters tested included accuracy, precision, linearity, robustness, stability of the virus stocks and system suitability. The MARV and EBOV assays were confirmed to be accurate to ±0.5 log10 PFU/mL. Repeatability precision, intermediate precision and reproducibility precision were sufficient to return viral titers with a coefficient of variation (%CV of ≤30%, deemed acceptable variation for a cell-based bioassay. Intraclass correlation statistical techniques for the evaluation of the assay’s precision when the same plaques were quantitated by two analysts returned values passing the acceptance criteria, indicating high agreement between analysts. The assay was shown to be accurate and specific when run on Nonhuman Primates (NHP serum and plasma samples diluted in plaque assay medium, with negligible matrix effects. Virus stocks demonstrated stability for freeze-thaw cycles typical of normal usage during assay retests. The results demonstrated that the EBOV and MARV plaque assays are accurate, precise and robust for filovirus titration in samples associated with the performance of GLP animal model studies.

Efficacy of hyaluronic acid binding assay in selecting motile spermatozoa with normal morphology at high magnification

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Mauri Ana L

2010-12-01

Full Text Available Abstract Background The present study aimed to evaluate the efficacy of the hyaluronic acid (HA binding assay in the selection of motile spermatozoa with normal morphology at high magnification (8400x. Methods A total of 16592 prepared spermatozoa were selected and classified into two groups: Group I, spermatozoa which presented their head attached to an HA substance (HA-bound sperm, and Group II, those spermatozoa that did not attach to the HA substance (HA-unbound sperm. HA-bound and HA-unbound spermatozoa were evaluated according to the following sperm forms: 1-Normal morphology: normal nucleus (smooth, symmetric and oval configuration, length: 4.75+/-2.8 μm and width: 3.28+/-0.20 μm, no extrusion or invagination and no vacuoles occupied more than 4% of the nuclear area as well as acrosome, post-acrosomal lamina, neck, tail, besides not presenting a cytoplasmic droplet or cytoplasm around the head; 2-Abnormalities of nuclear form (a-Large/small; b-Wide/narrow; c-Regional disorder; 3-Abnormalities of nuclear chromatin content (a-Vacuoles: occupy >4% to 50% of the nuclear area and b-Large vacuoles: occupy >50% of the nuclear area using a high magnification (8400x microscopy system. Results No significant differences were obtained with respect to sperm morphological forms and the groups HA-bound and HA-unbound. 1-Normal morphology: HA-bound 2.7% and HA-unbound 2.5% (P = 0.56. 2-Abnormalities of nuclear form: a-Large/small: HA-bound 1.6% vs. HA-unbound 1.6% (P = 0.63; b-Wide/narrow: HA-bound 3.1% vs. HA-unbound 2.7% (P = 0.13; c-Regional disorders: HA-bound 4.7% vs. HA-unbound 4.4% (P = 0.34. 3. Abnormalities of nuclear chromatin content: a-Vacuoles >4% to 50%: HA-bound 72.2% vs. HA-unbound 72.5% (P = 0.74; b-Large vacuoles: HA-bound 15.7% vs. HA-unbound 16.3% (P = 0.36. Conclusions The findings suggest that HA binding assay has limited efficacy in selecting motile spermatozoa with normal morphology at high magnification.

Time-resolved immunofluorometric assay of serum ferritin

Energy Technology Data Exchange (ETDEWEB)

Yan, Yao [China Inst. of Atomic Energy, Beijing (China)

2007-06-15

This assay is a solid phase, two-site fluoroimmunometric assay based on the direct sandwish technique. Standards or samples containing ferritin are first reacted with immobilized anti-ferritin antibodies. Then the europium-lablled antibodies are reacted with the bound antigen. The range of this assay is 2-1000 ng/mL. The analytical sentivity is better than 0.05 ng/mL. The intra-assay variation and inter-assay variation are both below 5%; This kit was compared with Wallac DELFIA kit. The correlation is r=0.96. (authors)

An enzyme-linked immunosorbent assay for the quantification of serum platelet-bindable IgG.

Science.gov (United States)

Howe, S E; Lynch, D M; Lynch, J M

1984-01-01

An enzyme-linked immunosorbent assay (ELISA) using F(ab')2 peroxidase-labeled antihuman immunoglobulin and o-phenylenediamine dihydrochloride (OPD) as a substrate was developed to measure serum platelet bindable IgG (S-PBIgG). The assay was made quantitative by standardizing the number of normal "target" platelets bound to microtiter plate wells, and by incorporating quantitated IgG standards with each microtiter plate tested to prepare a standard calibration curve. By this method, S-PBIgG for normal individuals was 3.4 +/- 1.6 fg per platelet (mean +/- 1 SD; n = 40). Increased S-PBIgG levels were detected in 36 of 40 patients with clinical autoimmune thrombocytopenia (ATP), ranging from 7.0 to 85 fg per platelet. Normal S-PBIgG levels were found in 34 of 40 patients with nonimmune thrombocytopenia. This method showed a sensitivity of 90 percent, specificity of 85 percent, and in the sample population studied, a positive predictive value of 0.86 and a negative predictive value of 0.90. This assay is highly reproducible (coefficient of variation was 6.8%) and appears useful in the evaluation of patients with suspected immune-mediated thrombocytopenia.

Evaluation of the standard normal variate method for Laser-Induced Breakdown Spectroscopy data treatment applied to the discrimination of painting layers

Science.gov (United States)

Syvilay, D.; Wilkie-Chancellier, N.; Trichereau, B.; Texier, A.; Martinez, L.; Serfaty, S.; Detalle, V.

2015-12-01

Nowadays, Laser-Induced Breakdown Spectroscopy (LIBS) is frequently used for in situ analyses to identify pigments from mural paintings. Nonetheless, in situ analyses require a robust instrumentation in order to face to hard experimental conditions. This may imply variation of fluencies and thus inducing variation of LIBS signal, which degrades spectra and then results. Usually, to overcome these experimental errors, LIBS signal is processed. Signal processing methods most commonly used are the baseline subtraction and the normalization by using a spectral line. However, the latter suggests that this chosen element is a constant component of the material, which may not be the case in paint layers organized in stratigraphic layers. For this reason, it is sometimes difficult to apply this normalization. In this study, another normalization will be carried out to throw off these signal variations. Standard normal variate (SNV) is a normalization designed for these conditions. It is sometimes implemented in Diffuse Reflectance Infrared Fourier Transform Spectroscopy and in Raman Spectroscopy but rarely in LIBS. The SNV transformation is not newly applied on LIBS data, but for the first time the effect of SNV on LIBS spectra was evaluated in details (energy of laser, shot by shot, quantification). The aim of this paper is the quick visualization of the different layers of a stratigraphic painting sample by simple data representations (3D or 2D) after SNV normalization. In this investigation, we showed the potential power of SNV transformation to overcome undesired LIBS signal variations but also its limit of application. This method appears as a promising way to normalize LIBS data, which may be interesting for in-situ depth analyses.

An anatomical study of normal variations of circle of Willis in 132 fetus, newborn and adult

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Bateni F

2009-09-01

Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: Several studies have investigated the variations in the anatomy of each segment of circle of Willis whereas a few have addressed the variations of this arterial circle as a whole. In this study the entire circle of Willis and its variations were studied in a cohort of Iranian people and compared with previous reports."n"nMethods: Anatomical variations of the circle of Willis in 132 brains of Iranian cadavers (102 male adults and 30 fetuses and infants were studied. The dissection process was digitally filmed for further studies. Using computer software the external diameters of the vessels were measured and the circle variations were classified. The variations of the circle as a whole and segmental variations were compared with previous studies. "n"nResults: Uni-and bilateral hypoplasia of posterior communicating arteries (PcoAs constituted the most common variation in our study which was similar to previous works. Aplasia of the anterior cerebral artery (A1 and the posterior cerebral artery (P1 were not observed. In 3.3% of fetuses and infants and 3% of adult instances both right and left posterior communicating arteries were absent. There was one case of anterior communicating artery (AcoA aplasia in

On the efficient simulation of the left-tail of the sum of correlated log-normal variates

KAUST Repository

Alouini, Mohamed-Slim; Rached, Nadhir B.; Kammoun, Abla; Tempone, Raul

2018-01-01

The sum of log-normal variates is encountered in many challenging applications such as performance analysis of wireless communication systems and financial engineering. Several approximation methods have been reported in the literature. However

Normal variation in early parental sensitivity predicts child structural brain development.

Science.gov (United States)

Kok, Rianne; Thijssen, Sandra; Bakermans-Kranenburg, Marian J; Jaddoe, Vincent W V; Verhulst, Frank C; White, Tonya; van IJzendoorn, Marinus H; Tiemeier, Henning

2015-10-01

Early caregiving can have an impact on brain structure and function in children. The influence of extreme caregiving experiences has been demonstrated, but studies on the influence of normal variation in parenting quality are scarce. Moreover, no studies to date have included the role of both maternal and paternal sensitivity in child brain maturation. This study examined the prospective relation between mothers' and fathers' sensitive caregiving in early childhood and brain structure later in childhood. Participants were enrolled in a population-based prenatal cohort. For 191 families, maternal and paternal sensitivity was repeatedly observed when the child was between 1 year and 4 years of age. Head circumference was assessed at 6 weeks, and brain structure was assessed using magnetic resonance imaging (MRI) measurements at 8 years of age. Higher levels of parental sensitivity in early childhood were associated with larger total brain volume (adjusted β = 0.15, p = .01) and gray matter volume (adjusted β = 0.16, p = .01) at 8 years, controlling for infant head size. Higher levels of maternal sensitivity in early childhood were associated with a larger gray matter volume (adjusted β = 0.13, p = .04) at 8 years, independent of infant head circumference. Associations with maternal versus paternal sensitivity were not significantly different. Normal variation in caregiving quality is related to markers of more optimal brain development in children. The results illustrate the important role of both mothers and fathers in child brain development. Copyright © 2015 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

Potential clinical impact of normal-tissue intrinsic radiosensitivity testing

International Nuclear Information System (INIS)

Bentzen, Soeren M.

1997-01-01

A critical appraisal is given of the possible benefit from a reliable pre-treatment knowledge of individual normal-tissue sensitivity to radiotherapy. The considerations are in part, but not exclusively, based on the recent experience with in vitro colony-forming assays of the surviving fraction at 2 Gy, the SF 2 . Three strategies are reviewed: (1) to screen for rare cases with extreme radiosensitivity, so-called over-reactors, and treat these with reduced total dose, (2) to identify the sensitive tail of the distribution of 'normal' radiosensitivities, refer these patients to other treatment, and to escalate the dose to the remaining patients, or (3) to individualize dose prescriptions based on individual radiosensitivity, i.e. treating to isoeffect rather than to a specific dose-fractionation schedule. It is shown that these strategies will have a small, if any, impact on routine radiotherapy. Screening for over-reactors is hampered by the low prevalence of these among otherwise un-selected patients that leads to a low positive predictive value of in vitro radiosensitivity assays. It is argued, that this problem may persist even if the noise on current assays could be reduced to (the unrealistic value of) zero, simply because of the large biological variation in SF 2 . Removing the sensitive tail of the patient population, will only have a minor effect on the dose that could be delivered to the remaining patients, because of the sigmoid shape of empirical dose-response relationships. Finally, individualizing dose prescriptions based exclusively on information from a normal-tissue radiosensitivity assay, leads to a nearly symmetrical distribution of dose-changes that would produce a very small gain, or even a loss, of tumor control probability if implemented in the clinic. From a theoretical point of view, other strategies could be devised and some of these are considered in this review. Right now the most promising clinical use of in vitro radiosensitivity

Solid-phase immunoradiometric assay for serum amyloid A protein using magnetisable cellulose particles

International Nuclear Information System (INIS)

De Beer, F.C.; Dyck, R.F.; Pepys, M.B.

1982-01-01

An immunoradiometric assay for human serum amyloid A protein (SAA) was developed using magnetisable cellulose particles as the solid phase. Rabbit antiserum to SAA was raised by immunization with SAA isolated from acute-phase serum by gel filtration in formic acid. The antiserum was rendered monospecific for SAA by solid-phase immunoabsorption with normal human serum, which contains only traces of SAA, and some was coupled covalently to the cellulose particles. Immunopurified anti-SAA antibodies were isolated from the monospecific anti-SAA serum by binding to, and elution from insolubilized acute-phase serum and were radiolabelled with 125 I. The assay was calibrated with an acute phase serum which contained 6000 times more SAA than normal sera with the lowest detectable level of SAA, and an arbitrary value of 6000 U/l was assigned to this standard. Sera were tested in the native, undenatured state and there was no increase in SAA immunoreactivity following alkali treatment or heating. The assay range was from 1-2000 U/l so that all SAA levels above 6 U/l could be measured on a single (1:6) dilution of serum. The intra- and interassay coefficients of variation were 11.7 and 15.0% respectively. Among 100 healthy normal subjects (50 male, 50 female) the median SAA level was 9 U/l, range <1-100, with 93% below 20 U/l and only 2% below the lower limit of sensitivity of the assay (1 U/l). (Auth.)

Analytical and between-subject variation of thrombin generation measured by calibrated automated thrombography on plasma samples.

Science.gov (United States)

Kristensen, Anne F; Kristensen, Søren R; Falkmer, Ursula; Münster, Anna-Marie B; Pedersen, Shona

2018-05-01

The Calibrated Automated Thrombography (CAT) is an in vitro thrombin generation (TG) assay that holds promise as a valuable tool within clinical diagnostics. However, the technique has a considerable analytical variation, and we therefore, investigated the analytical and between-subject variation of CAT systematically. Moreover, we assess the application of an internal standard for normalization to diminish variation. 20 healthy volunteers donated one blood sample which was subsequently centrifuged, aliquoted and stored at -80 °C prior to analysis. The analytical variation was determined on eight runs, where plasma from the same seven volunteers was processed in triplicates, and for the between-subject variation, TG analysis was performed on plasma from all 20 volunteers. The trigger reagents used for the TG assays included both PPP reagent containing 5 pM tissue factor (TF) and PPPlow with 1 pM TF. Plasma, drawn from a single donor, was applied to all plates as an internal standard for each TG analysis, which subsequently was used for normalization. The total analytical variation for TG analysis performed with PPPlow reagent is 3-14% and 9-13% for PPP reagent. This variation can be minimally reduced by using an internal standard but mainly for ETP (endogenous thrombin potential). The between-subject variation is higher when using PPPlow than PPP and this variation is considerable higher than the analytical variation. TG has a rather high inherent analytical variation but considerable lower than the between-subject variation when using PPPlow as reagent.

Development of a genotype-by-sequencing immunogenetic assay as exemplified by screening for variation in red fox with and without endemic rabies exposure.

Science.gov (United States)

Donaldson, Michael E; Rico, Yessica; Hueffer, Karsten; Rando, Halie M; Kukekova, Anna V; Kyle, Christopher J

2018-01-01

Pathogens are recognized as major drivers of local adaptation in wildlife systems. By determining which gene variants are favored in local interactions among populations with and without disease, spatially explicit adaptive responses to pathogens can be elucidated. Much of our current understanding of host responses to disease comes from a small number of genes associated with an immune response. High-throughput sequencing (HTS) technologies, such as genotype-by-sequencing (GBS), facilitate expanded explorations of genomic variation among populations. Hybridization-based GBS techniques can be leveraged in systems not well characterized for specific variants associated with disease outcome to "capture" specific genes and regulatory regions known to influence expression and disease outcome. We developed a multiplexed, sequence capture assay for red foxes to simultaneously assess ~300-kbp of genomic sequence from 116 adaptive, intrinsic, and innate immunity genes of predicted adaptive significance and their putative upstream regulatory regions along with 23 neutral microsatellite regions to control for demographic effects. The assay was applied to 45 fox DNA samples from Alaska, where three arctic rabies strains are geographically restricted and endemic to coastal tundra regions, yet absent from the boreal interior. The assay provided 61.5% on-target enrichment with relatively even sequence coverage across all targeted loci and samples (mean = 50×), which allowed us to elucidate genetic variation across introns, exons, and potential regulatory regions (4,819 SNPs). Challenges remained in accurately describing microsatellite variation using this technique; however, longer-read HTS technologies should overcome these issues. We used these data to conduct preliminary analyses and detected genetic structure in a subset of red fox immune-related genes between regions with and without endemic arctic rabies. This assay provides a template to assess immunogenetic variation

Natures and incidences of each normal variations on I.V.P. series of 1000 Korean females

International Nuclear Information System (INIS)

Shin, Ok Ja; Chin, Soo Yil

1980-01-01

Each organ of body has many normal variation and/or abnormal developments from fetus to adult, especially urogenital system is very complex and markedly abnormal. The authors attempt to analyze the natures, incidences and differences of each normal variations based on I.V.P. series of 1000 Korean females and the review of literatures were carried out. The results are as follows: 1. The normal variations of urinary tracts are about 30 kinds as follows; Aphasia 0/1000 (0%), Hypoplasia 4/1000 (0.4%), Atrophic kidney 0/1000 (0%), Hyperplasia 0/1000 (0%), Hypertrophied kidney 0/1000 (0%), Supernumerary kidney 0/1000 (0%), Pelvic kidney 0/1000 (0%), Wandering kidney 7/1000 (7%), Horseshoe kidney 2/1000 (2%), Nephroptosis 6/1000 (0.6%), Malroated kidney 0/1000 (0%), Crossed ecotopic kidney 0/1000 (0%), Ureteral kingking 440/1000 (44.0%), Short ureter 3/1000 (0.3%), Long ureter 49/1000 (4.9%), Retrocaval ureter 0/1000 (0%), Retroiliac ureter 0/1000 (0%), Mega-ureter 0/1000 (0%), Aberrant vessel in ureter 79/1000 (7.9%), Congenital ureteral valves 0/1000 (0%), Anomalous ureteral orifices 0/1000 (0%), Double ureter 22/1000 (2.2%), Ureteral diverticulum 0/1000 (0%), Extrarenal pelvis 170/1000 (17.0%), Intrarenal pelvis 830/1000 (83.0%), Supernumerary pelvis 55/1000 (55%), Renal backflow 2/1000 0.2%), Multiple calyces 0/1000 (0.1%), Calyceal diverticulum 2/1000 (0.2%), Unilateral fused kidney 0/1000 (0%), Polar enlarged kidney 0/1000 (0%). 2. The order of incidence of common variations in Korean females are as follows: 1. Intrarenal pelvis 2. Ureteral kingking 3. Extrarenal pelvis 4. Aberrant vessel in ureter 5. Double pelvis 6. Long ureter 7. Double ureter 8. Wandering Kidney 9. Nephrotosis 10. Hypoplasia 11. Short ureter 12. Horseshoe kidney 13. Renal backflow 14. Calyceal diverticulum 15. Supernumerary calyces. 3. The most common variations in Korean females are intrarenal pelvis, extrarenal pelvis, aberrant vessel in ureters and most of them are acquired origin. Contrary

The narrow therapeutic window of glycated hemoglobin and assay variability.

Science.gov (United States)

Hosseini, S S; Bibler, I; Charles, M A

1999-12-01

Glycated hemoglobin is measured by a variety of assays, each of which has a unique normal level. Our purpose is to show that among the different assays available in the United States, using the same patient's blood sample, assay results may vary widely and may more or less easily achieve a glycated hemoglobin value within the normal range. The following assays were compared using the same patient's blood sample for each pair of assays: glycohemoglobin affinity assay (GHB Reader; Isolab, Akron, OH) versus gel electrophoresis assay (n = 76); Isolab versus ion capture assay (IMX; Abbott Laboratories, Irving, TX) (n = 57); monoclonal antibody assay (DCA2000; Bayer Diagnostics, Pittsburgh, PA) versus IMX (n = 100); and high-performance liquid chromatography (HPLC) assay (Bio-Rad Variant A1c; Bio-Rad Laboratories, Richmond, CA) versus IMX assay (n = 55). Our analyses indicate that a relative ranking can be established for the ease of achieving a normal glycated hemoglobin level. The ranking indicates that the most stringent or difficult assays for achieving a normal level are the Isolab and DCA2000 assays. The intermediate assays are the IMX and Bio-Rad Variant, and the easiest method for achieving a normal value is the gel electrophoresis assay. Our results indicate that various glycated hemoglobin assays vary widely and are associated with more or less difficulty for an individual patient to achieve a glycated hemoglobin level within the normal range. These results are especially significant with respect to (1) the clinically narrow therapeutic window of glycated hemoglobin values in type 1 diabetes to avoid rapidly advancing severe hypoglycemia rates and chronic microvascular complication rates, and (2) the glycated hemoglobin threshold for rapidly advancing macrovascular disease in both type 1 and type 2 patients.

Monoclonal antibodies against human angiotensinogen, their characterization and use in an angiotensinogen enzyme linked immunosorbent assay.

Science.gov (United States)

Rubin, I; Lykkegaard, S; Olsen, A A; Selmer, J; Ballegaard, M

1988-01-01

Monoclonal antibodies were produced against human angiotensinogen. An enzyme linked immunosorbent assay (ELISA) was developed using a high affinity monoclonal antibody as catching antibody and a polyclonal rabbit anti human angiotensinogen antibody as detecting antibody in a "sandwich" ELISA. Linear range of the ELISA was 15-450 pmol/l of human angiotensinogen. Intra- and inter- assay variation coefficients were in the range of 2% to 8%. A correlation coefficient, r = 0.97, (n = 20), with values obtained by radioimmunoassay. This correlation coefficient, obtained by using both normal and pregnant sera, confirmed that the ELISA fulfill the requirements for clinical useful assay. Characterization of the antibodies were performed with respect to affinity constant and epitopes.

Apparent diffusion coefficient values of the normal uterus: Interindividual variations during menstrual cycle

International Nuclear Information System (INIS)

Tsili, A.C.; Argyropoulou, M.I.; Tzarouchi, L.; Dalkalitsis, N.; Koliopoulos, G.; Paraskevaidis, E.; Tsampoulas, K.

2012-01-01

Objectives: To assess the apparent diffusion coefficient (ADC) changes of the normal uterine zones among reproductive women during the menstrual cycle. Methods: The study included 101 women of reproductive age, each with regular cycle and normal endometrium/myometrium, as proved on histopathology or MR imaging examination. Diffusion-weighted (DW) imaging was performed along the axial plane, using a single shot, multi-slice spin-echo planar diffusion pulse sequence and b-values of 0 and 800 s/mm 2 . The mean and standard deviation of the ADC values of normal endometrium/myometrium were calculated for menstrual, proliferative and secretory phase. Analysis of variance followed by the least significant difference test was used for statistical analysis. Results: The ADC values of the endometrium were different in the three phases of the menstrual cycle (menstrual phase: 1.25 ± 0.27; proliferative phase: 1.39 ± 0.20; secretory phase: 1.50 ± 0.18) (F: 9.64, p: 0.00). Statistical significant difference was observed among all groups (p 0.05). Conclusions: A wide variation of ADC values of normal endometrium and myometrium is observed during different phases of the menstrual cycle.

The effects of variations in the specificities of the antibody components on a two-site immunoradiometric assay for ferritin

International Nuclear Information System (INIS)

Cowan, S.I.; Stagg, B.H.; Niemann, E.

1977-01-01

Variations in the sub-unit antigenic structure of ferritins derived from various human tissues are reflected in the differing specificities of antisera raised against these ferritin preparations. In this study it was shown that antibody specificity played an important role in determining the sensitivity and overall binding of labelled antibody in a two-site immunoradiometric assay for ferritin. Homologous assay systems, in which solid phase and radiolabelled antibodies were of similar specificities, were generally less sensitive and showed lower binding than heterologous assay systems, in which solid phase and labelled antibodies were of different specificities. The source of the ferritin which was used as assay standard also played an important part in determining the sensitivity and overall binding in homologous antibody systems, spleen ferritin standards yielding assays superior to those obtained with placenta or liver ferritin standards. However, these differences between standards were not seen in a heterologous system employing solid phase antibodies directed against liver ferritin and labelled antibodies directed against placenta ferritin. The nature of the ferritin used to prepare immunoadsorbant for the purification of antibodies prior to radioiodination also affected the assay characteristics; antibodies prepared on spleen ferritin immunoadsorbant being more reactive than antibodies prepared on placenta ferritin immunoadsorbant, which in turn were more reactive then antibodies prepared on liver ferritin immunoadsorbant. (orig.) [de

Estimated Uncertainty in Segmented Gamma Scanner Assay Results due to the Variation in Drum Tare Weights

International Nuclear Information System (INIS)

Bosko, A.; Croft, St.; Gulbransen, E.

2009-01-01

General purpose gamma scanners are often used to assay unknown drums that differ from those used to create the default calibration. This introduces a potential source of bias into the matrix correction when the correction is based on the estimation of the mean density of the drum contents from a weigh scale measurement. In this paper we evaluate the magnitude of this bias that may be introduced by performing assay measurements with a system whose matrix correction algorithm was calibrated with a set of standard drums but applied to a population of drums whose tare weight may be different. The matrix correction factors are perturbed in such cases because the unknown difference in tare weight gets reflected as a bias in the derived matrix density. This would be the only impact if the difference in tare weight was due solely to the weight of the lid or base, say. But in reality the reason for the difference may be because the steel wall of the drum is of a different thickness. Thus, there is an opposing interplay at work which tends to compensate. The purpose of this work is to evaluate and bound the magnitude of the resulting assay uncertainty introduced by tare weight variation. We compare the results obtained using simple analytical models and the 3-D ray tracing with ISOCS software to illustrate and quantify the problem. The numerical results allow a contribution to the Total Measurement Uncertainty (TMU) to be propagated into the final assay result. (authors)

The comet assay: ready for 30 more years.

Science.gov (United States)

Møller, Peter

2018-02-24

During the last 30 years, the comet assay has become widely used for the measurement of DNA damage and repair in cells and tissues. A landmark achievement was reached in 2016 when the Organization for Economic Co-operation and Development adopted a comet assay guideline for in vivo testing of DNA strand breaks in animals. However, the comet assay has much more to offer than being an assay for testing DNA strand breaks in animal organs. The use of repair enzymes increases the range of DNA lesions that can be detected with the assay. It can also be modified to measure DNA repair activity. Still, despite the long-term use of the assay, there is a need for studies that assess the impact of variation in specific steps of the procedure. This is particularly important for the on-going efforts to decrease the variation between experiments and laboratories. The articles in this Special Issue of Mutagenesis cover important technical issues of the comet assay procedure, nanogenotoxicity and ionising radiation sensitivity on plant cells. The included biomonitoring studies have assessed seasonal variation and certain predictors for the basal level of DNA damage in white blood cells. Lastly, the comet assay has been used in studies on genotoxicity of environmental and occupational exposures in human biomonitoring studies and animal models. Overall, the articles in this Special Issue demonstrate the versatility of the comet assay and they hold promise that the assay is ready for the next 30 years.

Consideration of Normal Variation of Perfusion Measurements in the Quantitative Analysis of Myocardial Perfusion SPECT: Usefulness in Assessment of Viable Myocardium

International Nuclear Information System (INIS)

Paeng, Jin Chul; Lim, Il Han; Kim, Ki Bong; Lee, Dong Soo

2008-01-01

Although automatic quantification software of myocardial perfusion SPECT provides highly objective and reproducible quantitative measurements, there is still some limitation in the direct use of quantitative measurements. In this study we derived parameters using normal variation of perfusion measurements, and tried to test the usefulness of these parameters. In order to calculate normal variation of perfusion measurements on myocardial perfusion SPECT, 55 patients (M:F=28:27) of low-likelihood for coronary artery disease were enrolled and 201 Tl rest / 99m Tc-MIBI stress SPECT studies were performed. Using 20-segment model, mean (m) and standard deviation (SD) of perfusion were calculated in each segment. As a myocardial viability assessment group, another 48 patients with known coronary artery disease, who underwent coronary artery bypass graft surgery (CABG) were enrolled. 201 Tl rest / 99m Tc-MIBI stress / 201 Tl 24-hr delayed SPECT was performed before CABG and SPECT was followed up 3 months after CABG. From the preoperative 24-hr delayed SPECT, Q delay (perfusion measurement), Δ delay (Q delay .m) and Z delay ((Q delay .m)/SD) were defined and diagnostic performances of them for myocardial viability were evaluated using area under curve (AUC) on receiver operating characteristic (ROC) curve analysis. Segmental perfusion measurements showed considerable normal variations among segments. In men, the lowest segmental perfusion measurement was 51.8±6.5 and the highest segmental perfusion was 87.0±5.9, and they are 58.7±8.1 and 87.3±6.0, respectively in women. In the viability assessment, Q delay showed AUC of 0.633, while those for Δ delay and Z delay were 0.735 and 0.716, respectively. The AUCs of Δ delay and Z delay were significantly higher than that of Q delay (p=0.001 and 0.018, respectively). The diagnostic performance of Δ delay , which showed highest AUC, was 85% of sensitivity and 53% of specificity at the optimal cutoff of -24.7. On automatic

LC-MSMS assays of urinary cortisol, a comparison between four in-house assays.

Science.gov (United States)

Brossaud, Julie; Leban, Monique; Corcuff, Jean-Benoit; Boux de Casson, Florence; Leloupp, Anne-Gaëlle; Masson, Damien; Moal, Valérie; Bach-Ngohou, Kalyane

2018-06-27

Twenty-four hour urinary free cortisol (UFC) determination can be used for screening and follow-up of Cushing syndrome (CS). As immunoassay methods lack specificity for UFC measurement, the use of high-performance liquid chromatography coupled to mass spectrometer (LC-MSMS) is recommended. The aim of our study was to compare UFC results using four LC-MSMS methods performed in four independent laboratories in order to evaluate interlaboratory agreement. Frozen aliquots of 24-h urine samples (78 healthy volunteers and 20 patients with CS) were sent to four different laboratories for analysis. Following liquid-liquid or solid-liquid extraction, UFC were determined using four different LC-MSMS assay. UFC intra- and interassays variation coefficients were lower than 10% for each centre. External quality control results were not significantly different. UFC normal ranges (established from healthy volunteers) were 17-126, 15-134, 12-118 and 27-157 nmol/day, respectively. Classification of UFC from healthy volunteers and patients with CS using a 95th percentile threshold was similar. However, for extreme UFC values (270 nmol/day), negative or positive bias was noted. Even for highly specific methods such as LC-MSMS, variations of results can be found depending on analytical process. Validation of LC-MSMS methods including determination of the reference range is essential.

The normal anatomy and variations of the bronchial arteries: evaluation with multidetector computed tomography.

Science.gov (United States)

Yener, Özlem; Türkvatan, Aysel; Yüce, Gökhan; Yener, Ali Ümit

2015-02-01

In this study, we aimed to reveal the normal anatomy and variations of the bronchial arterial system and to determine the sex distribution of these variations by retrospectively reviewing the images of patients who underwent thoracal multidetector computed tomographic angiography for various reasons. Multidetector computed tomographic images of a total of 208 patients (151 men; mean age, 59 years) were retrospectively reviewed to assess the normal anatomy and variations of the bronchial arterial system. A total of 531 bronchial arteries (median, 3; minimum, 1; maximum, 5; mean, 2.5) were detected. The number (mean diameter) of the right bronchial arteries were higher than the left bronchial arteries (290 [1.43 mm] and 241 [1.26 mm], respectively; P arteries were higher with men than with women (2.58 [1.45 mm] and 2.47 [1.32 mm], respectively; P artery, and, secondarily (13.46%), the combination of 2 right (1 intercostal-bronchial trunk and 1 bronchial artery) and 1 left bronchial arteries. Seventy-eight ectopic bronchial arteries were detected in 59 cases (28.3%). They most commonly originated from the aortic arch (37.2%), the descending aorta below the level of T6 (35.9%), or the aortic branches (16.7%). The number of right ectopic bronchial arteries was significantly higher than the left ectopic bronchial arteries (50 [64%] vs 28 [36%]; P arteries was statistically higher with men versus women (45 [29.8%] vs 14 [24.6%]; P arteries can vary substantially among individuals. Multidetector computed tomographic angiography enables a detailed road map of the bronchial arterial system to interventional radiologists and thoracic surgeons. Copyright © 2015 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Fast Edge Detection and Segmentation of Terrestrial Laser Scans Through Normal Variation Analysis

Science.gov (United States)

Che, E.; Olsen, M. J.

2017-09-01

Terrestrial Laser Scanning (TLS) utilizes light detection and ranging (lidar) to effectively and efficiently acquire point cloud data for a wide variety of applications. Segmentation is a common procedure of post-processing to group the point cloud into a number of clusters to simplify the data for the sequential modelling and analysis needed for most applications. This paper presents a novel method to rapidly segment TLS data based on edge detection and region growing. First, by computing the projected incidence angles and performing the normal variation analysis, the silhouette edges and intersection edges are separated from the smooth surfaces. Then a modified region growing algorithm groups the points lying on the same smooth surface. The proposed method efficiently exploits the gridded scan pattern utilized during acquisition of TLS data from most sensors and takes advantage of parallel programming to process approximately 1 million points per second. Moreover, the proposed segmentation does not require estimation of the normal at each point, which limits the errors in normal estimation propagating to segmentation. Both an indoor and outdoor scene are used for an experiment to demonstrate and discuss the effectiveness and robustness of the proposed segmentation method.

Measurement of rat serum FSH by radioreceptor assay and comparison with radioimmunoassay

International Nuclear Information System (INIS)

Minegishi, Takashi; Igarashi, Masao; Wakabayashi, Katsumi

1980-01-01

Follicle stimulating hormone (FSH) in rat serum is successfully measured by a radioreceptor assay system employing PMS-treated immature rat ovary. The non-specific inhibitory effect of serum was partially overcome by the addition of merthiolate to every component, while the residual effect was compensated for by using FSH-free serum which was prepared by passing the pooled female diestrous rat sera through an immunoadsorbent column packed with anti-ovine FSH-coupled Sepharose 4B. The assay system consisted of 100 μl of Tris-MgCl 2 -BSA or standard, 100 μl of FSH-free serum or sample, 100 μl of the receptor preparation and 100 μl of 125 I-FSH. The incubation was carried out for 4 hr at 37 0 C and 500 μl of cold Tris-MgCl 2 -BSA was used for the termination. Serum FSH could be measured within a range of 0.125 - 16 ng NIAMDD rat FSH I-3/tube. The mean within-assay coefficient of variation was 10.5%. The mean between-assay coefficient of variation was 11.0%. The assay values obtained by RRA showed a good correlation to those by RIA under the same physiological states of the animals. The ratio of the assay values, RRA/RIA, was found to change according to the sex and the physiological states, e.g. around 1.3 in normal males and 1.7 in orchiectomized animals and 2.21 in female rats. Serum FSH levels in female rats obtained by RRA and RIA changed almost in parallel until 20:00 (hr) of proestrous day, but after the first surge of serum FSH they were not parallel. These facts seem to indicate possible changes in the affinity of FSH with its receptor according to the state of animals and lead to the problem of the heterogeneity of FSH. (author)

Apparent diffusion coefficient values of the normal uterus: Interindividual variations during menstrual cycle

Energy Technology Data Exchange (ETDEWEB)

Tsili, A.C., E-mail: a_tsili@yahoo.gr [Department of Clinical Radiology, University Hospital of Ioannina (Greece); Argyropoulou, M.I., E-mail: margyrop@cc.uoi.gr [Department of Clinical Radiology, University Hospital of Ioannina (Greece); Tzarouchi, L., E-mail: ltzar@cc.uoi.gr [Department of Clinical Radiology, University Hospital of Ioannina (Greece); Dalkalitsis, N., E-mail: ndalkal@cc.uoi.gr [Department of Obstetrics and Gynaecology, University Hospital of Ioannina (Greece); Koliopoulos, G., E-mail: georgekoliopoulos@yahoo.com [Department of Obstetrics and Gynaecology, University Hospital of Ioannina (Greece); Paraskevaidis, E., E-mail: eparaske@cc.uoi.gr [Department of Obstetrics and Gynaecology, University Hospital of Ioannina (Greece); Tsampoulas, K., E-mail: ctsampou@uoi.gr [Department of Clinical Radiology, University Hospital of Ioannina (Greece)

2012-08-15

Objectives: To assess the apparent diffusion coefficient (ADC) changes of the normal uterine zones among reproductive women during the menstrual cycle. Methods: The study included 101 women of reproductive age, each with regular cycle and normal endometrium/myometrium, as proved on histopathology or MR imaging examination. Diffusion-weighted (DW) imaging was performed along the axial plane, using a single shot, multi-slice spin-echo planar diffusion pulse sequence and b-values of 0 and 800 s/mm{sup 2}. The mean and standard deviation of the ADC values of normal endometrium/myometrium were calculated for menstrual, proliferative and secretory phase. Analysis of variance followed by the least significant difference test was used for statistical analysis. Results: The ADC values of the endometrium were different in the three phases of the menstrual cycle (menstrual phase: 1.25 {+-} 0.27; proliferative phase: 1.39 {+-} 0.20; secretory phase: 1.50 {+-} 0.18) (F: 9.64, p: 0.00). Statistical significant difference was observed among all groups (p < 0.05). The ADC values of the normal myometrium were different in the three phases of the menstrual cycle (menstrual phase: 1.91 {+-} 0.35; proliferative phase: 1.72 {+-} 0.27; secretory phase: 1.87 {+-} 0.28) (F: 3.60, p: 0.03). Statistical significant difference was observed between menstrual and proliferative phase and between proliferative and secretory phase (p < 0.05). No significant difference was noted between menstrual and secretory phase (p > 0.05). Conclusions: A wide variation of ADC values of normal endometrium and myometrium is observed during different phases of the menstrual cycle.

Absence of diurnal variation in visceromotor response to colorectal distention in normal Long Evans rats [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Sara Botschuijver

2016-01-01

Full Text Available Background: Enhanced colorectal sensitivity (i.e. visceral hypersensitivity is thought to be a pathophysiological mechanism in irritable bowel syndrome (IBS. In healthy men a circadian variation in rectal perception to colonic distention was described. Disturbed day and night rhythms, which occur in shift work and trans meridian flights, are associated with the prevalence of IBS. This raises the question whether disruptions of circadian control are responsible for the observed pathology in IBS. Prior to investigating altered rhythmicity in relation to visceral hypersensitivity in a rat model for IBS, it is relevant to establish whether normal rats display circadian variation similar to healthy men.  Methodology and findings: In rodents colorectal distension leads to reproducible contractions of abdominal musculature. We used quantification of this so called visceromotor response (VMR by electromyography (EMG to assess visceral sensitivity in rats. We assessed the VMR in normal male Long Evans rats at different time points of the light/dark cycle. Although a control experiment with male maternal separated rats confirmed that intentionally inflicted (i.e. stress induced changes in VMR can be detected, normal male Long Evans rats showed no variation in VMR along the light/dark cycle in response to colorectal distension. Conclusions: In the absence of a daily rhythm of colorectal sensitivity in normal control rats it is not possible to investigate possible aberrancies in our rat model for IBS.

Reducing the standard deviation in multiple-assay experiments where the variation matters but the absolute value does not.

Science.gov (United States)

Echenique-Robba, Pablo; Nelo-Bazán, María Alejandra; Carrodeguas, José A

2013-01-01

When the value of a quantity x for a number of systems (cells, molecules, people, chunks of metal, DNA vectors, so on) is measured and the aim is to replicate the whole set again for different trials or assays, despite the efforts for a near-equal design, scientists might often obtain quite different measurements. As a consequence, some systems' averages present standard deviations that are too large to render statistically significant results. This work presents a novel correction method of a very low mathematical and numerical complexity that can reduce the standard deviation of such results and increase their statistical significance. Two conditions are to be met: the inter-system variations of x matter while its absolute value does not, and a similar tendency in the values of x must be present in the different assays (or in other words, the results corresponding to different assays must present a high linear correlation). We demonstrate the improvements this method offers with a cell biology experiment, but it can definitely be applied to any problem that conforms to the described structure and requirements and in any quantitative scientific field that deals with data subject to uncertainty.

Evaluation of an enzyme-linked immunosorbent assay for determination of porcine haptoglobin

DEFF Research Database (Denmark)

Petersen, H. H.; Nielsen, J. P.; Jensen, A.L.

2001-01-01

An enzyme-linked immunosorbent assay for quantification of haptoglobin in porcine serum was evaluated. Tbe detection limit when expressed as the estimated concentration of a blank sample was 0.0003 mg/ml. The precision of the assay was acceptable with intra-assay coefficients of variation below 4...... % and inter-assay coefficient of variation below 5 % for serum concentrations ranging from 1.0 mg/ml and above. For samples with a concentration below 0.8 mg/ml, the inter-assay coefficient of variation was above 10 %. The assay maintained linearity under dilution. Recovery was proportional. Haemolysis.......2. The maximum allowable analytical imprecision was 2.6 % and the maximum analytical inaccuracy was 9.9 %. The number of samples required to determine, the true haptoglobin value in an individual pig when accounting for the day-to-day fluctuation was 5. In conclusion, the haptoglobin assay was found...

Evaluation of total PSA assay on vitros ECi and correlation with Kryptor-PSA assay.

Science.gov (United States)

Cassinat, B; Wacquet, M; Toubert, M E; Rain, J D; Schlageter, M H

2001-01-01

An increasing number of multiparametric immuno-analysers for PSA assays are available. As different immuno-assays may vary in their analytical quality and their accuracy for the follow-up of patients, expertise is necessary for each new assay. The PSA assay on the Vitros-ECi analyser has been evaluated and compared with the PSA assay from the Kryptor analyser. Variation coefficients were 0.91 to 1.98% for within-run assays, and 4.2% to 5.4% for interassay (PSA levels = 0.8 microgram/L to 33.6 micrograms/L). Dilution tests showed 93 to 136% recovery until 70 micrograms/L PSA. Functional sensitivity was estimated at 0.03 microgram/L. Equimolarity of the test was confirmed. Correlation of PSA levels measured with Vitros-ECi and Kryptor analysers displayed a correlation coefficient r2 of 0.9716. The half-lives and doubling times of PSA were similar using both methods. Vitros-ECi PSA assay meets the major criteria for the management of prostate cancer patients.

Assessment of radiation induced cytogenetic damage in human keratinocytes by comet assay

International Nuclear Information System (INIS)

Joseph, Praveen; Sanjeev Ganesh; Narayana, Y.; Puthali, Abhay; Bhat, N.N.

2010-01-01

In the present study the effect of gamma radiation on normal human keratinocytes (HaCaT) cells has been analyzed using alkaline comet assay and a comparative study over the sensitivity of different comet parameters such as tail length (TL), olive tail moment (OTM) and percentage tail DNA (TDNA) has also been made. Human keratinocytes (HaCaT) cells were grown in Dulbecco's modified essential medium (DMEM) (10% FCS) at 37 °C in a humidified atmosphere containing 5% CO 2 . Cultured cells were harvested with 0.025 % trypsin EDTA. The sample (2 X 10 cells/ml) was exposed to gamma radiation of different dose using a 60 Co gamma source at dose rate of 2 Gy min -1 and the dosimetry has been carried out using Fricke and FBX dosimeters. After irradiation, to quantify the DNA damage the comet assay (single cell gel electrophoresis) was carried out under alkaline conditions, by the methods outlined by Singh et al. The quantification of the DNA strand breaks in each cells were performed using CASP software. The DNA damage quantification can be accomplished by measuring those comet parameters which exhibit a linear dependence on the amount of DNA damage. In the present study, comet parameters such as OTM, TL and TDNA were recorded and the variation of these parameters and their correlation coefficients for different doses of gamma radiation is plotted. The OTM value is normalized with control value and control for TL and TDNA is adjusted to zero to avoid initial variations in different experiments

A quantitative assay measuring the function of lipase maturation factor 1

Science.gov (United States)

Yin, Fen; Doolittle, Mark H.; Péterfy, Miklós

2009-01-01

Newly synthesized lipoprotein lipase (LPL) and related members of the lipase gene family require an endoplasmic reticulum maturation factor for attainment of enzyme activity. This factor has been identified as lipase maturation factor 1 (Lmf1), and mutations affecting its function and/or expression result in combined lipase deficiency (cld) and hypertriglyceridemia. To assess the functional impact of Lmf1 sequence variations, both naturally occurring and induced, we report the development of a cell-based assay using LPL activity as a quantitative reporter of Lmf1 function. The assay uses a cell line homozygous for the cld mutation, which renders endogenous Lmf1 nonfunctional. LPL transfected into the mutant cld cell line fails to attain activity; however, cotransfection of LPL with wild-type Lmf1 restores its ability to support normal lipase maturation. In this report, we describe optimized conditions that ensure the detection of a complete range of Lmf1 function (full, partial, or complete loss of function) using LPL activity as the quantitative reporter. To illustrate the dynamic range of the assay, we tested several novel mutations in mouse Lmf1. Our results demonstrate the ability of the assay to detect and analyze Lmf1 mutations having a wide range of effects on Lmf1 function and protein expression. PMID:19471043

Linearization of the Bradford Protein Assay

OpenAIRE

Ernst, Orna; Zor, Tsaffrir

2010-01-01

Determination of microgram quantities of protein in the Bradford Coomassie brilliant blue assay is accomplished by measurement of absorbance at 590 nm. This most common assay enables rapid and simple protein quantification in cell lysates, cellular fractions, or recombinant protein samples, for the purpose of normalization of biochemical measurements. However, an intrinsic nonlinearity compromises the sensitivity and accuracy of this method. It is shown that under standard assay conditions, t...

Application of radioreceptor assay of benzodiazepines for toxicology

International Nuclear Information System (INIS)

Aaltonen, L.; Scheinin, M.

1982-01-01

A radioreceptor assay (RRA) for determining benzodiazepines (BZ) has been developed and applied to toxicological analysis of serum samples from 21 patients with acute BZ overdosage. The method was sensitive (e.g., lorazepam 17 nM, diazepam 41 nM), and specific for pharmacologically active BZ derivatives. The reproducibility of the results was good (intra-assay variation < 8%, inter-assay variation < 10%). Concentrations measured by the RRA showed a good correlation with those obtained by gas-liquid chromatographic analysis of the same samples. The quantitative results represent the sum of one or several parent substances and all biologically active metabolites, in proportion to their receptor binding affinities. (author)

A novel multiparametric flow cytometry-based cytotoxicity assay simultaneously immunophenotypes effector cells: comparisons to a 4 h 51Cr-release assay.

Science.gov (United States)

Kim, G G; Donnenberg, V S; Donnenberg, A D; Gooding, W; Whiteside, T L

2007-08-31

Natural killer (NK) cell-or T cell-mediated cytotoxicity traditionally is measured in 4-16 h (51)Cr-release assays (CRA). A new four-color flow cytometry-based cytotoxicity assay (FCC) was developed to simultaneously measure NK cell cytotoxicity and NK cell phenotype (CD3(-)CD16(+)CD56(+)). Target cells, K562 or Daudi, were labeled with Cell Tracker Orange (CTO) prior to the addition of effector cells. Following co-incubation, 7 amino-actinomycin D (7-AAD) was added to measure death of target cells. The phenotype of effectors, viability of targets, the formation of tumor-effector cell conjugates and absolute numbers of all cells were measured based on light scatter (FSC/SSC), double discrimination of the fluorescence peak integral and height, and fluorescence intensity. Kinetic studies (0.5 and 1 to 4 h) at different effector to target (E:T) cell ratios (50, 25, 12, and 6) confirmed that the 3 h incubation was optimal. The FCC assay is more sensitive than the CRA, has a coefficient of variation (CV) 8-13% and reliably measures NK cell-or lymphokine-activated killer (LAK) cell-mediated killing of target cells in normal controls and subjects with cancer. The FCC assay can be used to study a range of phenotypic attributes, in addition to lytic activity of various subsets of effector cells, without radioactive tracers and thus, it is relatively inexpensive. The FCC assay has a potential for providing information about molecular interactions underlying target cell lysis and thus becoming a major tool for studies of disease pathogenesis as well as development of novel immune therapies.

Rapid assessment of repair of ultraviolet DNA damage with a modified host-cell reactivation assay using a luciferase reporter gene and correlation with polymorphisms of DNA repair genes in normal human lymphocytes

Energy Technology Data Exchange (ETDEWEB)

Qiao Yawei; Spitz, Margaret R.; Guo Zhaozheng; Hadeyati, Mohammad; Grossman, Lawrence; Kraemer, Kenneth H.; Wei Qingyi

2002-11-30

As DNA repair plays an important role in genetic susceptibility to cancer, assessment of the DNA repair phenotype is critical for molecular epidemiological studies of cancer. In this report, we compared use of the luciferase (luc) reporter gene in a host-cell reactivation (HCR) (LUC) assay of repair of ultraviolet (UV) damage to DNA to use of the chloramphenicol (cat) gene-based HCR (CAT) assay we used previously for case-control studies. We performed both the assays on cryopreserved lymphocytes from 102 healthy non-Hispanic white subjects. There was a close correlation between DNA repair capacity (DRC) as measured by the LUC and CAT assays. Although these two assays had similar variation, the LUC assay was faster and more sensitive. We also analyzed the relationship between DRC and the subjects' previously determined genotypes for four polymorphisms of two nucleotide-excision repair (NER) genes (in intron 9 of xeroderma pigmentosum (XP) C and exons 6, 10 and 23 of XPD) and one polymorphism of a base-excision repair gene in exon 10 of X-ray complementing group 1 (XRCC1). The DRC was significantly lower in subjects homozygous for one or more polymorphisms of the two NER genes than in subjects with other genotypes (P=0.010). In contrast, the polymorphic XRCC1 allele had no significant effect on DRC. These results suggest that the post-UV LUC assay measures NER phenotype and that polymorphisms of XPC and XPD genes modulate DRC. For population studies of the DNA repair phenotype, many samples need to be evaluated, and so the LUC assay has several advantages over the CAT assay: the LUC assay was more sensitive, had less variation, was not radioactive, was easier to perform, and required fewer cryopreserved cells. These features make the LUC-based HCR assay suitable for molecular epidemiological studies.

Comparison of Batch Assay and Random Assay Using Automatic Dispenser in Radioimmunoassay

Energy Technology Data Exchange (ETDEWEB)

Moon, Seung Hwan; Jang, Su Jin; Kang, Ji Yeon; Lee, Dong Soo; Chung, June Key; Lee, Myung Chul [Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul (Korea, Republic of); Lee, Ho Young; Shin, Sun Young; Min, Gyeong Sun; Lee, Hyun Joo [Seoul National University college of Medicine, Seoul (Korea, Republic of)

2009-08-15

Radioimmunoassay (RIA) was usually performed by the batch assay. To improve the efficiency of RIA without increase of the cost and time, random assay could be a choice. We investigated the possibility of the random assay using automatic dispenser by assessing the agreement between batch assay and random assay. The experiments were performed with four items; Triiodothyronine (T3), free thyroxine (fT4), Prostate specific antigen (PSA), Carcinoembryonic antigen (CEA). In each item, the sera of twenty patients, the standard, and the control samples were used. The measurements were done 4 times with 3 hour time intervals by random assay and batch assay. The coefficient of variation (CV) of the standard samples and patients' data in T3, fT4, PSA, and CEA were assessed. ICC (Intraclass correlation coefficient) and coefficient of correlation were measured to assessing the agreement between two methods. The CVs (%) of T3, fT4, PSA, and CEA measured by batch assay were 3.2+-1.7%, 3.9+-2.1%, 7.1+-6.2%, 11.2+-7.2%. The CVs by random assay were 2.1+-1.7%, 4.8+-3.1%, 3.6+-4.8%, and 7.4+-6.2%. The ICC between the batch assay and random assay were 0.9968 (T3), 0.9973 (fT4), 0.9996 (PSA), and 0.9901 (CEA). The coefficient of correlation between the batch assay and random assay were 0.9924(T3), 0.9974 (fT4), 0.9994 (PSA), and 0.9989 (CEA) (p<0.05). The results of random assay showed strong agreement with the batch assay in a day. These results suggest that random assay using automatic dispenser could be used in radioimmunoassay

Comparison of Batch Assay and Random Assay Using Automatic Dispenser in Radioimmunoassay

International Nuclear Information System (INIS)

Moon, Seung Hwan; Jang, Su Jin; Kang, Ji Yeon; Lee, Dong Soo; Chung, June Key; Lee, Myung Chul; Lee, Ho Young; Shin, Sun Young; Min, Gyeong Sun; Lee, Hyun Joo

2009-01-01

Radioimmunoassay (RIA) was usually performed by the batch assay. To improve the efficiency of RIA without increase of the cost and time, random assay could be a choice. We investigated the possibility of the random assay using automatic dispenser by assessing the agreement between batch assay and random assay. The experiments were performed with four items; Triiodothyronine (T3), free thyroxine (fT4), Prostate specific antigen (PSA), Carcinoembryonic antigen (CEA). In each item, the sera of twenty patients, the standard, and the control samples were used. The measurements were done 4 times with 3 hour time intervals by random assay and batch assay. The coefficient of variation (CV) of the standard samples and patients' data in T3, fT4, PSA, and CEA were assessed. ICC (Intraclass correlation coefficient) and coefficient of correlation were measured to assessing the agreement between two methods. The CVs (%) of T3, fT4, PSA, and CEA measured by batch assay were 3.2±1.7%, 3.9±2.1%, 7.1±6.2%, 11.2±7.2%. The CVs by random assay were 2.1±1.7%, 4.8±3.1%, 3.6±4.8%, and 7.4±6.2%. The ICC between the batch assay and random assay were 0.9968 (T3), 0.9973 (fT4), 0.9996 (PSA), and 0.9901 (CEA). The coefficient of correlation between the batch assay and random assay were 0.9924(T3), 0.9974 (fT4), 0.9994 (PSA), and 0.9989 (CEA) (p<0.05). The results of random assay showed strong agreement with the batch assay in a day. These results suggest that random assay using automatic dispenser could be used in radioimmunoassay

Biomonitoring of genotoxic risk in radar facility workers: comparison of the comet assay with micronucleus assay and chromatid breakage assay

International Nuclear Information System (INIS)

Garaj-Vrhovac, V.; Kopjar, N.

2003-01-01

Genotoxic risks of occupational exposure in a radar facility were evaluated by using alkaline comet assay, micronucleus assay and chromatid breakage assay on peripheral blood leukocytes in exposed subjects and corresponding controls. Results show that occupational exposure to microwave radiation correlates with an increase of genome damage in somatic cells. The levels of DNA damage in exposed subjects determined by using alkaline comet assay were increased compared to control and showed interindividual variations. Incidence of micronuclei was also significantly increased compared to baseline control values. After short exposure of cultured lymphocytes to bleomycin, cells of occupationally exposed subjects responded with high numbers of chromatid breaks. Although the level of chromosome damage generated by bleomycin varied greatly between individuals, in exposed subjects a significantly elevated number of chromatid breaks was observed. Our results support data reported in literature indicating that microwave radiation represents a potential DNA-damaging hazard. Alkaline comet assay is confirmed as a sensitive and highly reproducible technique for detection of primary DNA damage inflicted in somatic cells. Micronucleus assay was confirmed as reliable bio-markers of effect and chromatid breakage assay as sensitive bio-marker of individual cancer susceptibility. The results obtained also confirm the necessity to improve measures and to perform accurate health surveillance of individuals occupationally exposed to microwave radiation

Relaxation time of normal breast tissues. Changes with age and variations during the menstrual cycle

International Nuclear Information System (INIS)

Dean, K.I.; Majurin, M.L.; Komu, M.

1994-01-01

The influence of age on the relaxation times of normal breast parenchyma and its surrounding fatty tissue were evaluated, and the variations during a normal menstrual cycle were analyzed using an ultra low field 0.02 T imager. Thirty-nine healthy volunteers aged 21 to 59 years were examined to determine T1 and T2 relaxation times, and 8 of these volunteers were studied once weekly during one menstrual cycle. The only significant trend was an increase in the T2 of breast parenchyma with increasing age. During the menstrual cycle there was a slight but insignificant (p=0.10) increase in T1 of the breast parenchyma values during the latter half of the menstrual cycle, and a corresponding increase in T2 values between the 2nd and 3rd weeks of the menstrual cycle, which was significant. (orig.)

Relaxation time of normal breast tissues. Changes with age and variations during the menstrual cycle

Energy Technology Data Exchange (ETDEWEB)

Dean, K.I. (University Central Hospital, Turku (Finland). Dept. of Diagnostic Radiology); Majurin, M.L. (University Central Hospital, Turku (Finland). Dept. of Diagnostic Radiology); Komu, M. (University Central Hospital, Turku (Finland). Dept. of Diagnostic Radiology)

1994-05-01

The influence of age on the relaxation times of normal breast parenchyma and its surrounding fatty tissue were evaluated, and the variations during a normal menstrual cycle were analyzed using an ultra low field 0.02 T imager. Thirty-nine healthy volunteers aged 21 to 59 years were examined to determine T1 and T2 relaxation times, and 8 of these volunteers were studied once weekly during one menstrual cycle. The only significant trend was an increase in the T2 of breast parenchyma with increasing age. During the menstrual cycle there was a slight but insignificant (p=0.10) increase in T1 of the breast parenchyma values during the latter half of the menstrual cycle, and a corresponding increase in T2 values between the 2nd and 3rd weeks of the menstrual cycle, which was significant. (orig.).

The circadian variation in Anti-Müllerian hormone in patients with polycystic ovary syndrome differs significantly from normally ovulating women

DEFF Research Database (Denmark)

Bungum, Leif Johan; Franssohn, Florencia; Bungum, Mona Berger Håkonsen

2013-01-01

To improve the biologic understanding of the Polycystic Ovarian Syndrome (PCOS) condition by examining the circadian variation and relationship between Anti Müllerian Hormone (AMH), gonadotropins and ovarian steroids in PCOS patients compared to normally ovulating and menstruating women....... By comparing the pattern of co-variation between AMH and Luteinizing Hormone, two compounds closely linked to hyperandrogenism and anovulation in PCOS, the involvement of the Hypothalamic-Pituitary-Ovarian axis in PCOS pathology could be elucidated....

Smooth quantile normalization.

Science.gov (United States)

Hicks, Stephanie C; Okrah, Kwame; Paulson, Joseph N; Quackenbush, John; Irizarry, Rafael A; Bravo, Héctor Corrada

2018-04-01

Between-sample normalization is a critical step in genomic data analysis to remove systematic bias and unwanted technical variation in high-throughput data. Global normalization methods are based on the assumption that observed variability in global properties is due to technical reasons and are unrelated to the biology of interest. For example, some methods correct for differences in sequencing read counts by scaling features to have similar median values across samples, but these fail to reduce other forms of unwanted technical variation. Methods such as quantile normalization transform the statistical distributions across samples to be the same and assume global differences in the distribution are induced by only technical variation. However, it remains unclear how to proceed with normalization if these assumptions are violated, for example, if there are global differences in the statistical distributions between biological conditions or groups, and external information, such as negative or control features, is not available. Here, we introduce a generalization of quantile normalization, referred to as smooth quantile normalization (qsmooth), which is based on the assumption that the statistical distribution of each sample should be the same (or have the same distributional shape) within biological groups or conditions, but allowing that they may differ between groups. We illustrate the advantages of our method on several high-throughput datasets with global differences in distributions corresponding to different biological conditions. We also perform a Monte Carlo simulation study to illustrate the bias-variance tradeoff and root mean squared error of qsmooth compared to other global normalization methods. A software implementation is available from https://github.com/stephaniehicks/qsmooth.

Revaluation of biological variation of glycated hemoglobin (HbA(1c)) using an accurately designed protocol and an assay traceable to the IFCC reference system.

Science.gov (United States)

Braga, Federica; Dolci, Alberto; Montagnana, Martina; Pagani, Franca; Paleari, Renata; Guidi, Gian Cesare; Mosca, Andrea; Panteghini, Mauro

2011-07-15

Glycated hemoglobin (HbA(1c)) has a key role for diagnosing diabetes and monitoring glycemic state. As recently reviewed, available data on HbA(1c) biological variation show marked heterogeneity. Here we experimentally revaluated these data using a well designed protocol. We took five EDTA whole blood specimens from 18 apparently healthy subjects on the same day, every two weeks for two months. Samples were stored at -80°C until analysis and assayed in duplicate in a single run by Roche Tina-quant® Gen.2 immunoassay. Data were analyzed by the ANOVA. To assess the assay traceability to the IFCC reference method, we preliminarily carried out a correlation experiment. The bias (mean±SD) of the Roche immunoassay was 0.3%±0.7%, confirming the traceability of the employed assay. No difference was found in HbA(1c) values between men and women. Within- and between-subject CV were 2.5% and 7.1%, respectively. Derived desirable analytical goals for imprecision, bias, and total error resulted 1.3%, 1.9%, and 3.9%, respectively. HbA(1c) had marked individuality, limiting the use of population-based reference limits for test interpretation. The estimated critical difference was ~10%. For the first time we defined biological variation and derived indices for the clinical application of HbA(1c) measurements using an accurately designed protocol and an assay standardized according to the IFCC. Copyright © 2011 Elsevier B.V. All rights reserved.

A rapid, accurate and robust particle-based assay for the simultaneous screening of plasma samples for the presence of five different anti-cytokine autoantibodies

DEFF Research Database (Denmark)

Guldager, Daniel Kring Rasmussen; von Stemann, Jakob Hjorth; Larsen, Rune

2015-01-01

suitable for larger screenings. Based on confirmed antibody binding characteristics and the resultant reactivity in this multiplex assay, a classification of the c-aAb levels was suggested. The screening results of the recipients who received blood transfusions indicate that more studies are needed...... plasma samples and pooled normal immunoglobulin preparations were used to validate the assay. Plasma samples from 98 transfusion recipients, half of whom presented with febrile reactions, were tested by the assay. RESULTS: The assay detected specific and saturable immunoglobulin G (IgG) binding to each...... cytokine autoantibodies quantities in the negative plasma samples ranged between 80% and 125%. The analytical intra- and inter-assay variations were 4% and 11%, respectively. Varying c-aAb levels were detectable in the transfusion recipients. There was no difference in c-aAb frequency between the patients...

LDLCHOLESTEROLEXAMINATION (LDL-C USINGHOMOGENEOUS ASSAY

Directory of Open Access Journals (Sweden)

Made DwiAmbara Putra

2013-07-01

Full Text Available Homogeneous method describe as a method that does not require separation of free and bound label. This method has the ability tofully automate the determination of LDL-C directly small sample volume sand short examination time. In addition this method use automated pipette and control of time and temperature more accurate. There are 5 methods i.e. Solubilization homogeneous LDL-C assay (SOL from KyowaMedex, Surfactant LDL-C assay (SUR from Daiichi Pure Chemicals, Protecting LDL-assay reagent (PRO from Wako Chemicals, LDL-C assaycatalase (CAT Denka Seiken and Calixarene of LDL-C assay (CAL from International Reagents Corporation. All method is to use a variety of detergents and other chemicals that cause blocking or dissolution of specific lipoprotein classes to achieve specificity for LDL. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

Variation in the measurement of DNA damage by comet assay measured by the ECVAG dagger inter-laboratory validation trial

DEFF Research Database (Denmark)

Forchhammer, Lykke; Johansson, Clara; Loft, Steffen

2010-01-01

the level of DNA damage in monocyte-derived THP-1 cells by either visual classification or computer-aided image analysis of pre-made slides, coded cryopreserved samples of cells and reference standard cells (calibration curve samples). The reference standard samples were irradiated with ionizing radiation...... by the different laboratories as evidenced by an inter-laboratory coefficient of variation (CV) of 47%. Adjustment of the primary comet assay end points by a calibration curve prepared in each laboratory reduced the CV to 28%, a statistically significant reduction (P test). A large fraction...

Evaluation of a molybdenum assay canister

International Nuclear Information System (INIS)

Yoshizumi, T.T.; Keener, S.J.

1988-01-01

The performance characteristics of a commercial molybdenum assay canister were evaluated. The geometrical variation of the technetium-99m (/sup 99m/Tc) activity reading was studied as a function of the elution volume for the standard vials. It was found that the /sup 99m/Tc canister activity reading was ∼ 5% lower than that of the standard method. This is due to attenuation by the canister wall. However, the effect of the geometric variation on the clinical dose preparation was found to be insignificant. The molybdenum-99 ( 99 Mo) contamination level was compared by two methods: (1) the commercial canister and (2) the standard assay kit. The 99 Mo contamination measurements with the canister indicated consistently lower readings than those with the standard 99 Mo assay kit. The authors conclude that the canister may be used in the clinical settings. However, the user must be aware of the problems and the limitations associated with this canister

Hemizona Assay and Sperm Penetration Assay in the Prediction of IVF Outcome: A Systematic Review

Directory of Open Access Journals (Sweden)

Paraskevi Vogiatzi

2013-01-01

Full Text Available The limited predictive value of semen analysis in achieving natural conception or in IVF outcome confirms the need for sperm function tests to determine optimal management. We reviewed HZA and SPA predictive power in IVF outcome, with statistical significance of diagnostic power of the assays. HZA was readily efficient in predicting IVF outcome, while evident inconsistency among the studies analysed framed the SPA’s role in male fertility evaluation. Considerable variation was noted in the diagnostic accuracy values of SPA with wide sensitivity (52–100%, specificity (0–100%, and PPV (18–100% and NPV (0–100% together with fluctuation and notable differentiation in methodology and cutoff values employed by each group. HZA methodology was overall consistent with minor variation in cutoff values and oocyte source, while data analysis reported strong correlation between HZA results with IVF outcome, high sensitivity (75–100%, good specificity (57–100%, and high PPV (79–100% and NPV (68–100%. HZA correlated well with IVF outcome and demonstrated better sensitivity/specificity and positive/negative predictive power. Males with normal or slightly abnormal semen profiles could benefit by this intervention and could be evaluated prior to referral to assisted reproduction. HZA should be used in a sequential fashion with semen analysis and potentially other bioassays in an IVF setting.

Tumor and normal tissue motion in the thorax during respiration: Analysis of volumetric and positional variations using 4D CT

International Nuclear Information System (INIS)

Weiss, Elisabeth; Wijesooriya, Krishni; Dill, S. Vaughn; Keall, Paul J.

2007-01-01

Purpose: To investigate temporospatial variations of tumor and normal tissue during respiration in lung cancer patients. Methods and Materials: In 14 patients, gross tumor volume (GTV) and normal tissue structures were manually contoured on four-dimensional computed tomography (4D-CT) scans. Structures were evaluated for volume changes, centroid (center of mass) motion, and phase dependence of variations relative to inspiration. Only volumetrically complete structures were used for analysis (lung in 2, heart in 8, all other structures in >10 patients). Results: During respiration, the magnitude of contoured volumes varied up to 62.5% for GTVs, 25.5% for lungs, and 12.6% for hearts. The range of maximum three-dimensional centroid movement for individual patients was 1.3-24.0 mm for GTV, 2.4-7.9 mm for heart, 5.2-12.0 mm for lungs, 0.3-5.5 mm for skin markers, 2.9-10.0 mm for trachea, and 6.6-21.7 mm for diaphragm. During respiration, the centroid positions of normal structures varied relative to the centroid position of the respective GTV by 1.5-8.1 mm for heart, 2.9-9.3 mm for lungs, 1.2-9.2 mm for skin markers, 0.9-7.1 mm for trachea, and 2.7-16.4 mm for diaphragm. Conclusion: Using 4D-CT, volumetric changes, positional alterations as well as changes in the position of contoured structures relative to the GTV were observed with large variations between individual patients. Although the interpretation of 4D-CT data has considerable uncertainty because of 4D-CT artifacts, observer variations, and the limited acquisition time, the findings might have a significant impact on treatment planning

An accurate method for quantifying and analyzing copy number variation in porcine KIT by an oligonucleotide ligation assay

Directory of Open Access Journals (Sweden)

Cho In-Cheol

2007-11-01

Full Text Available Abstract Background Aside from single nucleotide polymorphisms, copy number variations (CNVs are the most important factors in susceptibility to genetic disorders because they affect expression levels of genes. In previous studies, pyrosequencing, mini-sequencing, real-time PCR, invader assays and other techniques have been used to detect CNVs. However, the higher the copy number in a genome, the more difficult it is to resolve the copies, so a more accurate method for measuring CNVs and assigning genotype is needed. Results PCR followed by a quantitative oligonucleotide ligation assay (qOLA was developed for quantifying CNVs. The accuracy and precision of the assay were evaluated for porcine KIT, which was selected as a model locus. Overall, the root mean squares of bias and standard deviation of qOLA were 2.09 and 0.45, respectively. These values are less than half of those in the published pyrosequencing assay for analyzing CNV in porcine KIT. Using a combined method of qOLA and another pyrosequencing for quantitative analysis of KIT copies with spliced forms, we confirmed the segregation of KIT alleles in 145 F1 animals with pedigree information and verified the correct assignment of genotypes. In a diagnostic test on 100 randomly sampled commercial pigs, there was perfect agreement between the genotypes obtained by grouping observations on a scatter plot and by clustering using the nearest centroid sorting method implemented in PROC FASTCLUS of the SAS package. In a test on 159 Large White pigs, there were only two discrepancies between genotypes assigned by the two clustering methods (98.7% agreement, confirming that the quantitative ligation assay established here makes genotyping possible through the accurate measurement of high KIT copy numbers (>4 per diploid genome. Moreover, the assay is sensitive enough for use on DNA from hair follicles, indicating that DNA from various sources could be used. Conclusion We have established a high

Computed tomography for the detection of distal radioulnar joint instability: normal variation and reliability of four CT scoring systems in 46 patients

Energy Technology Data Exchange (ETDEWEB)

Wijffels, Mathieu; Krijnen, Pieta; Schipper, Inger [Leiden University Medical Center, Department of Surgery-Trauma Surgery, P.O. Box 9600, Leiden (Netherlands); Stomp, Wouter; Reijnierse, Monique [Leiden University Medical Center, Department of Radiology, P.O. Box 9600, Leiden (Netherlands)

2016-11-15

The diagnosis of distal radioulnar joint (DRUJ) instability is clinically challenging. Computed tomography (CT) may aid in the diagnosis, but the reliability and normal variation for DRUJ translation on CT have not been established in detail. The aim of this study was to evaluate inter- and intraobserver agreement and normal ranges of CT scoring methods for determination of DRUJ translation in both posttraumatic and uninjured wrists. Patients with a conservatively treated, unilateral distal radius fracture were included. CT scans of both wrists were evaluated independently, by two readers using the radioulnar line method, subluxation ratio method, epicenter method and radioulnar ratio method. The inter- and intraobserver agreement was assessed and normal values were determined based on the uninjured wrists. Ninety-two wrist CTs (mean age: 56.5 years, SD: 17.0, mean follow-up 4.2 years, SD: 0.5) were evaluated. Interobserver agreement was best for the epicenter method [ICC = 0.73, 95 % confidence interval (CI) 0.65-0.79]. Intraobserver agreement was almost perfect for the radioulnar line method (ICC = 0.82, 95 % CI 0.77-0.87). Each method showed a wide normal range for normal DRUJ translation. Normal range for the epicenter method is -0.35 to -0.06 in pronation and -0.11 to 0.19 in supination. DRUJ translation on CT in pro- and supination can be reliably evaluated in both normal and posttraumatic wrists, however with large normal variation. The epicenter method seems the most reliable. Scanning of both wrists might be helpful to prevent the radiological overdiagnosis of instability. (orig.)

21 CFR 862.1660 - Quality control material (assayed and unassayed).

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Quality control material (assayed and unassayed... Test Systems § 862.1660 Quality control material (assayed and unassayed). (a) Identification. A quality... that may arise from reagent or analytical instrument variation. A quality control material (assayed and...

System for nondestructive assay of spent fuel subassemblies: comparison of calculations and measurements

International Nuclear Information System (INIS)

Ragan, G.L; Ricker, C.W.; Chiles, M.M.; Ingersoll, D.T.; Slaughter, G.G.; Williams, L.R.

1979-01-01

A nondestructive assay system was developed for determining the total fissile content of spent fuel subassemblies at the head end of a reprocessing plant. The system can perform an assay in 20 min with an uncertainty of <5%. Antimony-beryllium neutrons interrogate the subassemblies, and proton recoil counters detect the resulting fission neutrons. Pulse-height discrimination differentiates between the low-energy interrogation neutrons and the higher-energy fission neutrons. Calculated and measured results were compared for (1) interrogation-neutron penetrability, (2) fission-neutron detectability, (3) radial variation of assay sensitivity, (4) axial variation of assay sensitivity, and (5) the variation of detector count rate as a function of the number of fuel rods in a special 61-rod, LMFBR-type subassembly

Electroimmunoassay, radioimmunoassay, and radial immunodiffusion assay evaluated for quantification of human apolipoprotein B

International Nuclear Information System (INIS)

Curry, M.D.; Gustafson, A.; Alaupovic, P.; McConathy, W.J.

1978-01-01

We examined three immunoassay techniques for measuring apolipoprotein B in serum and major lipoprotein density fractions from normolipidemic and hyperlipoproteinemic persons, comparing values by electroimmunoassay, radioimmunoassay, and radial immunodiffusion assay with those determined gravimetrically. Electroimmunoassay is faster and simpler than radioimmunoassay, and equally precise (within- and between-assay coefficients of variation for both were 5 and 7%, respectively). All the immunoassays gave results that agreed with those by gravimetry for normolipidemic sera and the corresponding lipoprotein density fractions, but only electroimmunoassay results agreed with those by gravimetry for apolipoprotein B in lipoproteins of d < 1.019 g/ml isolated from hypertriglyceridemic patients. Concentrations of apolipoprotein B in plasma, determined by electroimmunoassay in a population of normal persons and patients with primary hyperlipoproteinemias, were: normals, 980 +- 200; type 1, 700 +- 160; type IIa, 2000 +- 260; type IIb, 2180 +- 300; type III, 1300 +- 340; type IV, 1470 +- 400; and type V, 1550 +- 390 mg/liter (mean +- SD). Lipoprotein density fractions from the hyperlipoproteinemic patients each had a characteristic distribution of free and associated forms of lipoprotein family B. The absolute concentration and distribution of apolipoprotein B between the free and associated forms of lipoprotein B may represent a useful indicator of the underlying biochemical defect

Interpretation of protein quantitation using the Bradford assay: comparison with two calculation models.

Science.gov (United States)

Ku, Hyung-Keun; Lim, Hyuk-Min; Oh, Kyong-Hwa; Yang, Hyo-Jin; Jeong, Ji-Seon; Kim, Sook-Kyung

2013-03-01

The Bradford assay is a simple method for protein quantitation, but variation in the results between proteins is a matter of concern. In this study, we compared and normalized quantitative values from two models for protein quantitation, where the residues in the protein that bind to anionic Coomassie Brilliant Blue G-250 comprise either Arg and Lys (Method 1, M1) or Arg, Lys, and His (Method 2, M2). Use of the M2 model yielded much more consistent quantitation values compared with use of the M1 model, which exhibited marked overestimations against protein standards. Copyright © 2012 Elsevier Inc. All rights reserved.

Radioisotopic 51Cr-leukocyte adherence inhibition (LAI) assay. I

International Nuclear Information System (INIS)

Tsang, P.H.; Tangnavarad, K.; Lesnick, G.; Holland, J.F.; Bekesi, J.G.; Perloff, M.

1980-01-01

A simplified radioisotopic leukocyte adherence inhibition assay ( 51 Cr-LAI assay) was used to determine tumor-directed immune responses in patients with cancer of the breast. Essential steps in development of this assay are the standardization of conditions for optimal 51 Cr uptake by peripheral blood lymphocytes (PBL) and the inclusion of autologous or normal AB serum in the incubation media. A dextrose salt mixture (GNK) was found to enhance intracellular uptake of 51 Cr significantly (8-fold) without affecting viability of the cells or without causing selective loss of lymphocyte subpopulations. The presence of 10% autologous or normal AB serum prevented non-specific LAI responses to unrelated tumor antigens. Experimental results are presented and it is seen that this short term (4 h) 51 Cr-LAI assay provides reproducible and specific results analogous to those using tube-LAI assay. The test has the advantages of being accurate, sensitive and free from technical bias. (Auth.)

Intensity Variation Normalization for Finger Vein Recognition Using Guided Filter Based Singe Scale Retinex.

Science.gov (United States)

Xie, Shan Juan; Lu, Yu; Yoon, Sook; Yang, Jucheng; Park, Dong Sun

2015-07-14

Finger vein recognition has been considered one of the most promising biometrics for personal authentication. However, the capacities and percentages of finger tissues (e.g., bone, muscle, ligament, water, fat, etc.) vary person by person. This usually causes poor quality of finger vein images, therefore degrading the performance of finger vein recognition systems (FVRSs). In this paper, the intrinsic factors of finger tissue causing poor quality of finger vein images are analyzed, and an intensity variation (IV) normalization method using guided filter based single scale retinex (GFSSR) is proposed for finger vein image enhancement. The experimental results on two public datasets demonstrate the effectiveness of the proposed method in enhancing the image quality and finger vein recognition accuracy.

Evaluating acoustic speaker normalization algorithms: evidence from longitudinal child data.

Science.gov (United States)

Kohn, Mary Elizabeth; Farrington, Charlie

2012-03-01

Speaker vowel formant normalization, a technique that controls for variation introduced by physical differences between speakers, is necessary in variationist studies to compare speakers of different ages, genders, and physiological makeup in order to understand non-physiological variation patterns within populations. Many algorithms have been established to reduce variation introduced into vocalic data from physiological sources. The lack of real-time studies tracking the effectiveness of these normalization algorithms from childhood through adolescence inhibits exploration of child participation in vowel shifts. This analysis compares normalization techniques applied to data collected from ten African American children across five time points. Linear regressions compare the reduction in variation attributable to age and gender for each speaker for the vowels BEET, BAT, BOT, BUT, and BOAR. A normalization technique is successful if it maintains variation attributable to a reference sociolinguistic variable, while reducing variation attributable to age. Results indicate that normalization techniques which rely on both a measure of central tendency and range of the vowel space perform best at reducing variation attributable to age, although some variation attributable to age persists after normalization for some sections of the vowel space. © 2012 Acoustical Society of America

Thermometric enzyme linked immunosorbent assay: TELISA.

Science.gov (United States)

Mattiasson, B; Borrebaeck, C; Sanfridson, B; Mosbach, K

1977-08-11

A new method, thermometric enzyme linked immunosorbent assay (TELISA), for the assay of endogenous and exogenous compounds in biological fluids is described. It is based on the previously described enzyme linked immunosorbent assay technique, ELISA, but utilizes enzymic heat formation which is measured in an enzyme thermistor unit. In the model system studied determination of human serum albumin down to a concentration of 10(-10) M (5 ng/ml) was achieved, with both normal and catalase labelled human serum albumin competing for the binding sites on the immunosorbent, which was rabbit antihuman serum albumin immobilized onto Sepharose CL-4B.

Comparison and validation of ELISA assays for plasma insulin-like ...

African Journals Online (AJOL)

1 in the horse. ... accurate and precise of the three kits; the other two assays gave apparently much lower concentrations, with poor recovery of spiked recombinant human IGF-1 and unacceptably poor intra-assay coefficients of variation (CV).

Imaging the corpus callosum, septum pellucidum and fornix in children: normal anatomy and variations of normality

International Nuclear Information System (INIS)

Griffiths, Paul D.; Batty, Ruth; Connolly, Dan J.A.; Reeves, Michael J.

2009-01-01

The midline structures of the supra-tentorial brain are important landmarks for judging if the brain has formed correctly. In this article, we consider the normal appearances of the corpus callosum, septum pellucidum and fornix as shown on MR imaging in normal and near-normal states. (orig.)

Development of a radioreceptor assay for human chorion gonadotropin: Application in normal and pathological pregnancies

International Nuclear Information System (INIS)

Koch, R.

1978-01-01

Rats testes were homogenised, and the binding capacity of several dilutions of these were tested with iodine 125 -labelled human choriongonadotropin. Investigations about binding over a period of 36 hrs. with 3 different temperatures, inhibition tests and cross reaction analyses for determining the specificity were carried out. 2 assay systems could be developed. The highly sensitive assay was applied at early pregnancy, at suspected disturbed or ectopic gravidity and allowed to measure the hCG-serum concentration above the physiological basal secretion of hLH. The less sensitive assay was used for measuring hCG in later stages of pregnancy, chorionepitheliomas and other hCG producing tumours. With the highly sensitive and specific assay, hCG was determinable 8 to 10 days post conceptionem. (orig.) [de

Assay-specific decision limits for two new automated parathyroid hormone and 25-hydroxyvitamin D assays.

Science.gov (United States)

Souberbielle, Jean-Claude; Fayol, Véronique; Sault, Corinne; Lawson-Body, Ethel; Kahan, André; Cormier, Catherine

2005-02-01

The recent development of nonradioactive automated assays for serum parathyroid hormone (PTH) and 25-hydroxyvitamin D (25OHD) has made measurement of these two hormones possible in many laboratories. In this study, we compared two new assays for PTH and 25OHD adapted on an automated analyzer, the LIAISON, with two manual immunoassays used worldwide. We studied 228 osteoporotic patients, 927 healthy individuals, 38 patients with primary hyperparathyroidism, and 167 hemodialyzed patients. Serum PTH was measured with the Allegro and the LIAISON assays, and 25OHD was measured with DiaSorin RIA and the LIAISON assay. Regression analysis was used to calculate decision thresholds for the LIAISON assays that were equivalent to those of the Allegro PTH and DiaSorin 25OHD assays. The 25OHD concentrations obtained with the LIAISON assay and the RIA in osteoporotic patients were well correlated (r = 0.83; P 50 nmol/L as eligible for the reference population for the LIAISON PTH assay. In this group, the 3rd-97th percentile interval for LIAISON PTH was 3-51 ng/L. Considering upper reference limits of 46 and 51 ng/L for the Allegro and LIAISON assays, respectively, the frequency of above-normal PTH concentrations in patients with primary hyperparathyroidism was similar in both assays. Regression analysis between serum PTH measured by the Allegro and LIAISON assays in 167 hemodialyzed patients and the corresponding Bland-Altman analysis of these data suggest that the LIAISON PTH assay tends to read higher than the Allegro assay at low concentrations but lower at high concentrations (>300 ng/L). Because clinical decision limits for both PTH and 25OHD should be assay specific, we propose equivalences between these assays and two manual assays used worldwide. These assay-specific decision limits should help potential users of the LIAISON PTH and 25OHD assays.

Direct measurement of the precursors of adrenocorticotropin in human plasma by two-site immunoradiometric assay

International Nuclear Information System (INIS)

Crosby, S.R.; Stewart, M.F.; Ratcliffe, J.G.; White, A.

1988-01-01

An immunoradiometric assay (IRMA) for the direct measurement of the precursors of ACTH in unextracted human plasma has been developed and evaluated clinically in normal subjects and patients with disorders of the hypothalamic-pituitary-adrenal axis. The IRMA is based on an iodinated monoclonal antibody to ACTH and a monoclonal antibody to gamma MSH coupled to Sephacryl S300. The assay detects only peptides containing both epitopes, i.e. POMC (31K) and pro-ACTH (22K). The reference standard was partially purified POMC from culture medium of human corticotroph adenoma cells. The detection limit (greater than +2.5SD of the 0 standard) was 2.0 pmol/L and the within-assay coefficient of variation was less than 10% between 29 and 2600 pmol/L. Plasma concentrations of ACTH precursor peptides in 11 normal subjects sampled at 0930 h ranged from 5-34 pmol/L. The concentrations in the patient groups studied were: 260-2300 pmol/L in 5 patients with the ectopic ACTH syndrome associated with small cell lung cancer, less than 2.0-104 pmol/L in 10 patients with pituitary-dependent Cushing's disease, 23 pmol/L in a patient with Nelson's syndrome, and 3.0-230 pmol/L in 5 patients with Addison's disease. We conclude that this IRMA offers a simple and reliable method for measuring ACTH precursors in unextracted plasma. The proportionately greater elevation of ACTH precursors compared to ACTH in patients with the ectopic ACTH syndrome associated with small cell lung cancer but not in pituitary-dependent Cushing's syndrome, suggests that this assay may be clinically useful

Radioreceptor assays: plasma membrane receptors and assays for polypeptide and glycoprotein hormones

International Nuclear Information System (INIS)

Schulster, D.

1977-01-01

Receptors for peptide, protein and glycoprotein hormones, and the catecholamines are located on the plasma membranes of their target cells. Preparations of the receptors may be used as specific, high-affinity binding agents for these hormones in assay methodology akin to that for radioimmunoassay. A particular advantage of the radioreceptor assay is that it has a specificity directed towards the biologically active region of the hormone, rather than to some immunologically active region that may have little (or no) involvement in the expression of hormonal activity. Methods for hormone receptor preparation vary greatly, and range from the use of intact cells (as the source of hormone receptor) to the use of purified or solubilized membrane receptors. Receptors isolated from plasma membranes have proved to be of variable stability, and may be damaged during preparation and/or storage. Moreover, since they are present in relatively low concentration in the cell, their preparation in sufficient quantity for use in a radioreceptor assay may present technical problems. In general, there is good correlation between radioreceptor assays and in-vitro bioassays; differences between results from radioreceptor assays and radioimmunoassays are similar to those noted between in-vitro bioassays and radioimmunoassays. The sensitivity of the method is such that normal plasma concentrations of various hormones have been assayed by this technique. (author)

An ultrafiltration assay for lysyl oxidase

International Nuclear Information System (INIS)

Shackleton, D.R.; Hulmes, D.J.

1990-01-01

A modification of the original microdistillation assay for lysyl oxidase is described in which Amicon C-10 microconcentrators are used to separate, by ultrafiltration, the 3H-labeled products released from a [4,5-3H]-lysine-labeled elastin substrate. Enzyme activity is determined by scintillation counting of the ultrafiltrate, after subtraction of radioactivity released in the presence of beta-aminopropionitrile, a specific inhibitor of the enzyme. Conditions are described which optimize both the sensitivity and the efficient use of substrate. The assay shows linear inhibition of activity in up to 1 M urea; hence, as the enzyme is normally diluted in the assay, samples in 6 M urea can be assayed directly, without prior dialysis, and corrected for partial inhibition. Comparable results are obtained when enzyme activity is assayed by ultrafiltration or microdistillation. The assay is simple and convenient and, by using disposable containers throughout, it eliminates the need for time-consuming decontamination of radioactive glassware

Intensity Variation Normalization for Finger Vein Recognition Using Guided Filter Based Singe Scale Retinex

Directory of Open Access Journals (Sweden)

Shan Juan Xie

2015-07-01

Full Text Available Finger vein recognition has been considered one of the most promising biometrics for personal authentication. However, the capacities and percentages of finger tissues (e.g., bone, muscle, ligament, water, fat, etc. vary person by person. This usually causes poor quality of finger vein images, therefore degrading the performance of finger vein recognition systems (FVRSs. In this paper, the intrinsic factors of finger tissue causing poor quality of finger vein images are analyzed, and an intensity variation (IV normalization method using guided filter based single scale retinex (GFSSR is proposed for finger vein image enhancement. The experimental results on two public datasets demonstrate the effectiveness of the proposed method in enhancing the image quality and finger vein recognition accuracy.

Pregnancy outcomes are not altered by variation in thyroid function within the normal range in women free of thyroid disease.

Science.gov (United States)

Veltri, Flora; Kleynen, Pierre; Grabczan, Lidia; Salajan, Alexandra; Rozenberg, Serge; Pepersack, Thierry; Poppe, Kris

2018-02-01

In the recently revised guidelines on the management of thyroid dysfunction during pregnancy, treatment with thyroid hormone (LT4) is not recommended in women without thyroid autoimmunity (TAI) and TSH levels in the range 2.5-4.0 mIU/L, and in a recent study in that particular group of pregnant women, more complications were observed when a treatment with LT4 was given. The objective of the study was therefore to investigate whether variation in thyroid function within the normal (non-pregnant) range in women free of thyroid disease was associated with altered pregnancy outcomes? Cross-sectional data analysis of 1321 pregnant women nested within an ongoing prospective collection of pregnant women's data in a single centre in Brussels, Belgium. Thyroid peroxidase antibodies (TPO-abs), thyroid-stimulating hormone (TSH), free T4 (FT4) and ferritin levels were measured and baseline characteristics were recorded. Women taking LT4, with TAI and thyroid function outside the normal non-pregnant range were excluded. Pregnancy outcomes and baseline characteristics were correlated with all TSH and FT4 levels within the normal range and compared between two groups (TSH cut-off 500 mL) was inversely associated with serum FT4 levels (OR: 0.35; CI 95%: 0.13-0.96); P  = 0.040. Also 10% of women free of thyroid disease had serum TSH levels ≥2.5 mIU/L. Variation in thyroid function during the first trimester within the normal (non-pregnant) range in women free of thyroid disease was not associated with altered pregnancy outcomes. These results add evidence to the recommendation against LT4 treatment in pregnant women with high normal TSH levels and without TPO antibodies. © 2018 European Society of Endocrinology.

Analytical and Clinical Performance Evaluation of the Abbott Architect PIVKA Assay.

Science.gov (United States)

Ko, Dae-Hyun; Hyun, Jungwon; Kim, Hyun Soo; Park, Min-Jeong; Kim, Jae-Seok; Park, Ji-Young; Shin, Dong Hoon; Cho, Hyoun Chan

2018-01-01

Protein induced by vitamin K absence (PIVKA) is measured using various assays and is used to help diagnose hepatocellular carcinoma. The present study evaluated the analytical and clinical performances of the recently released Abbott Architect PIVKA assay. Precision, linearity, and correlation tests were performed in accordance with the Clinical Laboratory Standardization Institute guidelines. Sample type suitability was assessed using serum and plasma samples from the same patients, and the reference interval was established using sera from 204 healthy individuals. The assay had coefficients of variation of 3.2-3.5% and intra-laboratory variation of 3.6-5.5%. Linearity was confirmed across the entire measurable range. The Architect PIVKA assay was comparable to the Lumipulse PIVKA assay, and the plasma and serum samples provided similar results. The lower reference limit was 13.0 mAU/mL and the upper reference limit was 37.4 mAU/mL. The ability of the Architect PIVKA assay to detect hepatocellular carcinoma was comparable to that of the alpha-fetoprotein test and the Lumipulse PIVKA assay. The Architect PIVKA assay provides excellent analytical and clinical performance, is simple for clinical laboratories to adopt, and has improved sample type suitability that could broaden the assay's utility. © 2018 by the Association of Clinical Scientists, Inc.

Radioimmunoassays of parathyroid hormone: Clinical value of the midregion and c-terminal assay

International Nuclear Information System (INIS)

Hengst, K.; Raidt, H.; Hoegemann, B.; Wagner, H.

1984-01-01

PTH was measured by midregion and carboxy-terminal assay in 20 patients suffering from primary hyperparathyroidism, 30 patients with secondary hyperparathyroidism, 10 persons with tertiary hyperparathyroidism, 50 patients who underwent transplantation of the kidney, 10 patients with hypoparathyroidism and 10 patients with other hypocalcemia as well as in 50 normal persons. Diagnosing hyperparathyroidism both assays were successful, when serum kreatinine was within the normal range. Especially midregion fragments became elevated, when serum kreatinine was above 2,0 mg. During renal failure diagnosis of hyperparathyroidism and hypoparathyroidism is more difficult. In normal renal function, however, the midregion assay is more sensitive for diagnosis of hypoparathyroidism compared to the carboxy-terminal assay. After kidney transplantation midregion levels of PTH are elevated, perhaps because of a failure of the transplanted kidney to eliminate the midregion fragment. (orig.) [de

Genetic Architecture of Natural Variation Underlying Adult Foraging Behavior That Is Essential for Survival of Drosophila melanogaster.

Science.gov (United States)

Lee, Yuh Chwen G; Yang, Qian; Chi, Wanhao; Turkson, Susie A; Du, Wei A; Kemkemer, Claus; Zeng, Zhao-Bang; Long, Manyuan; Zhuang, Xiaoxi

2017-05-01

Foraging behavior is critical for the fitness of individuals. However, the genetic basis of variation in foraging behavior and the evolutionary forces underlying such natural variation have rarely been investigated. We developed a systematic approach to assay the variation in survival rate in a foraging environment for adult flies derived from a wild Drosophila melanogaster population. Despite being such an essential trait, there is substantial variation of foraging behavior among D. melanogaster strains. Importantly, we provided the first evaluation of the potential caveats of using inbred Drosophila strains to perform genome-wide association studies on life-history traits, and concluded that inbreeding depression is unlikely a major contributor for the observed large variation in adult foraging behavior. We found that adult foraging behavior has a strong genetic component and, unlike larval foraging behavior, depends on multiple loci. Identified candidate genes are enriched in those with high expression in adult heads and, demonstrated by expression knock down assay, are involved in maintaining normal functions of the nervous system. Our study not only identified candidate genes for foraging behavior that is relevant to individual fitness, but also shed light on the initial stage underlying the evolution of the behavior. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

PHARMACOKINETIC VARIATIONS OF OFLOXACIN IN NORMAL AND FEBRILE RABBITS

Directory of Open Access Journals (Sweden)

M. AHMAD, H. RAZA, G. MURTAZA AND N. AKHTAR

2008-12-01

Full Text Available The influence of experimentally Escherichia coli-induced fever (EEIF on the pharmacokinetics of ofloxacin was evaluated. Ofloxacin was administered @ 20 mg.kg-1 body weight intravenously to a group of eight healthy rabbits and compared these results to values in same eight rabbits with EEIF. Pharmacokinetic parameters of ofloxacin in normal and febrile rabbits were determined by using two compartment open kinetic model. Peak plasma level (Cmax and area under the plasma concentration-time curve (AUC0-α in normal and febrile rabbits did not differ (P>0.05. However, area under first moment of plasma concentration-time curve (AUMC0-α in febrile rabbits was significantly (P<0.05 higher than that in normal rabbits. Mean values for elimination rate constant (Ke, elimination half life (t1/2β and apparent volume of distribution (Vd were significantly (P<0.05 lower in febrile rabbits compared to normal rabbits, while mean residence time (MRT and total body clearance (Cl of ofloxacin did not show any significant difference in the normal and febrile rabbits. Clinical significance of the above results can be related to the changes in the volume of distribution and elimination half life that illustrates an altered steady state in febrile condition; hence, the need for an adjustment of dosage regimen in EEIF is required.

Crate counter for normal operating loss

International Nuclear Information System (INIS)

Harlan, R.A.

A lithium-loaded zinc sulfide scintillation counter to closely assay plutonium in waste packaged in 1.3 by 1.3 by 2.13m crates was built. In addition to assays for normal operating loss accounting, the counter will allow safeguards verification immediately before shipment of the crates for burial. The counter should detect approximately 10 g of plutonium in 1000 kg of waste

Establishment and characterization of a new and stable collagen-binding assay for the assessment of von Willebrand factor activity

Science.gov (United States)

Ni, Y; Nesrallah, J; Agnew, M; Geske, F J; Favaloro, E J

2013-01-01

Introduction Laboratory diagnosis of von Willebrand disease (VWD) requires determination of both von Willebrand factor (VWF) protein levels and activity. Current VWF activity tests include the ristocetin cofactor assay and the collagen-binding assay (VWF:CB). The goal of this investigation is to characterize a new collagen-binding assay and to determine its effectiveness in identifying VWD. Methods Analytical studies were carried out to characterize the performance of a new VWF:CB ELISA. Additionally, samples from a normal population were tested as were well-characterized type 1 and type 2 VWD samples. Results Repeatability and within-laboratory precision studies resulted in coefficients of variation (CVs) of ≤11%. A linear range of 1–354% (0.01–3.54 IU/mL) was determined, along with a limit of detection and a lower limit of quantitation of 1.6% and 4.0% (0.016 and 0.04 IU/mL), respectively. Samples tested from apparently healthy individuals resulted in a normal range of 54–217% (0.54–2.17 IU/mL). Known VWD type 1 and type 2 samples were also analyzed by the ELISA, with 99% of samples having VWF:CB below the normal reference range and an estimated 96% sensitivity and 87% specificity using a VWF collagen-binding/antigen cutoff ratio of 0.50. Conclusion This new VWF:CB ELISA provides an accurate measure of collagen-binding activity that aids in the diagnosis and differentiation of type 1 from type 2 VWD. PMID:23107512

Survival of human diploid skin fibroblasts from normal individuals after X-irradiation

International Nuclear Information System (INIS)

Little, J.B.; Nove, J.; Strong, L.C.; Nichols, W.W.

1988-01-01

The cytotoxic effect of X-rays was measured by a colony formation assay in multiple experiments with fibroblast cell strains derived from 24 presumably normal individuals, received as 65 different coded and blinded samples. Each strain was received on two or more occasions at different times and bearing different codes. The means and standard deviations of the survival curve parameters for the 24 strains were: D 0 = 123 +- 23; D 10 = 273 +- 42 cGy. The D 0 ranged from 89 to 175 and the D 10 from 196 to 372 cGy. The degree of interexperimental variation, though generally minimal, differed considerably among cell strains. There was no systematic effect of passage level, cloning efficiency, serum lot, age or sex of the donor on X-ray survival. These results confirm that the intrinsic radiosensitivity varies significantly among skin fibroblasts isolated from clinically normal individuals, apparently owing to as yet unidentified genetic factors. (Author)

Experimental studies of breaking of elastic tired wheel under variable normal load

Science.gov (United States)

Fedotov, A. I.; Zedgenizov, V. G.; Ovchinnikova, N. I.

2017-10-01

The paper analyzes the braking of a vehicle wheel subjected to disturbances of normal load variations. Experimental tests and methods for developing test modes as sinusoidal force disturbances of the normal wheel load were used. Measuring methods for digital and analogue signals were used as well. Stabilization of vehicle wheel braking subjected to disturbances of normal load variations is a topical issue. The paper suggests a method for analyzing wheel braking processes under disturbances of normal load variations. A method to control wheel baking processes subjected to disturbances of normal load variations was developed.

Validation of an enzyme-linked immunosorbent assay (ELISA) for the measurement of canine S100A12.

Science.gov (United States)

Heilmann, Romy M; Cranford, Shannon M; Ambrus, Andy; Grützner, Niels; Schellenberg, Stefan; Ruaux, Craig G; Suchodolski, Jan S; Steiner, Jörg M

2016-03-01

Canine S100 calcium-binding protein A12 (cS100A12) shows promise as biomarker of inflammation in dogs. A previously developed cS100A12-radioimmunoassay (RIA) requires radioactive tracers and is not sensitive enough for fecal cS100A12 concentrations in 79% of tested healthy dogs. An ELISA assay may be more sensitive than RIA and does not require radioactive tracers. The purpose of the study was to establish a sandwich ELISA for serum and fecal cS100A12, and to establish reference intervals (RI) for normal healthy canine serum and feces. Polyclonal rabbit anti-cS100A12 antibodies were generated and tested by Western blotting and immunohistochemistry. A sandwich ELISA was developed and validated, including accuracy and precision, and agreement with cS100A12-RIA. The RI, stability, and biologic variation in fecal cS100A12, and the effect of corticosteroids on serum cS100A12 were evaluated. Lower detection limits were 5 μg/L (serum) and 1 ng/g (fecal), respectively. Intra- and inter-assay coefficients of variation were ≤ 4.4% and ≤ 10.9%, respectively. Observed-to-expected ratios for linearity and spiking recovery were 98.2 ± 9.8% (mean ± SD) and 93.0 ± 6.1%, respectively. There was a significant bias between the ELISA and the RIA. The RI was 49-320 μg/L for serum and 2-484 ng/g for fecal cS100A12. Fecal cS100A12 was stable for 7 days at 23, 4, -20, and -80°C; biologic variation was negligible but variation within one fecal sample was significant. Corticosteroid treatment had no clinically significant effect on serum cS100A12 concentrations. The cS100A12-ELISA is a precise and accurate assay for serum and fecal cS100A12 in dogs. © 2016 American Society for Veterinary Clinical Pathology.

Nondestructive assay of HTGR fuel rods

International Nuclear Information System (INIS)

Menlove, H.O.

1974-01-01

Performance characteristics of three different radioactive source NDA systems are compared for the assay of HTGR fuel rods and stacks of rods. These systems include the fast neutron Sb-Be assay system, the 252 Cf ''Shuffler,'' and the thermal neutron PAPAS assay system. Studies have been made to determinethe perturbation on the measurements from particle size, kernel Th/U ratio, thorium content, and hydrogen content. In addition to the total 235 U determination, the pellet-to-pellet or rod-to-rod uniformity of HTGR fuel rod stacks has been measured by counting the delayed gamma rays with a NaI through-hole in the PAPAS system. These measurements showed that rod substitutions can be detected easily in a fuel stack, and that detailed information is available on the loading variations in a uniform stack. Using a 1.0 mg 252 Cf source, assay rates of 2 to 4 rods/s are possible, thus facilitating measurement of 100 percent of a plant's throughput. (U.S.)

Assay of 25-OH vitamin D3

International Nuclear Information System (INIS)

Nayer, P. de; Thalasso, M.; Beckers, C.

1977-01-01

A simplified version of the competitive protein binding assay for 25-OH vit D3 derived from the method of Belsey et al. is presented. The procedure does not include a chromatography step, and is performed on an alcoolic extract of 0.1 ml plasma or serum. Normal rat serum (1:20,000) was used as binding protein. No β-lipoproteins were added to the assay buffer. A 10% displacement of the tracer was observed at 0.04 ng/tube, and 50% at 0.15 ng/tube, allowing for the measurement of 25-OH vit D3 concentrations between 2 ng/ml and 200 ng/ml. Mean values in a normal group was 23.1 +- 6.5 ng/ml (range 16-37 ng/ml, n = 11). (orig.) [de

The measurement of intrinsic cellular radiosensitivity in human tumours and normal tissues

International Nuclear Information System (INIS)

Lawton, P.A.

1995-01-01

Human tumour and normal cell radiosensitivity are thought to be important factors determining the response of tumour and normal tissues to radiotherapy, respectively. Clonogenic assays are the standard method for measuring radiosensitivity but they are of limited applicability for clinical use with fresh human tumours. The main aim of this work was to evaluate the Adhesive Tumour Cell Culture System (ATCCS), as a method for measuring the radiosensitivity of human tumours. A soft agar clonogenic assay, the modified Courtenay-Mills assay, was used as a standard to compare with the ATCCS. The demonstration that fibroblast contamination could occur with both assay methods led to the investigation of a new technique for removing unwanted fibroblasts from tumour cell suspensions and to the use of a multiwell assay for measuring fibroblast radiosensitivity. (author)

The measurement of intrinsic cellular radiosensitivity in human tumours and normal tissues

Energy Technology Data Exchange (ETDEWEB)

Lawton, P.A.

1995-12-31

Human tumour and normal cell radiosensitivity are thought to be important factors determining the response of tumour and normal tissues to radiotherapy, respectively. Clonogenic assays are the standard method for measuring radiosensitivity but they are of limited applicability for clinical use with fresh human tumours. The main aim of this work was to evaluate the Adhesive Tumour Cell Culture System (ATCCS), as a method for measuring the radiosensitivity of human tumours. A soft agar clonogenic assay, the modified Courtenay-Mills assay, was used as a standard to compare with the ATCCS. The demonstration that fibroblast contamination could occur with both assay methods led to the investigation of a new technique for removing unwanted fibroblasts from tumour cell suspensions and to the use of a multiwell assay for measuring fibroblast radiosensitivity. (author).

Linearization of the bradford protein assay.

Science.gov (United States)

Ernst, Orna; Zor, Tsaffrir

2010-04-12

Determination of microgram quantities of protein in the Bradford Coomassie brilliant blue assay is accomplished by measurement of absorbance at 590 nm. This most common assay enables rapid and simple protein quantification in cell lysates, cellular fractions, or recombinant protein samples, for the purpose of normalization of biochemical measurements. However, an intrinsic nonlinearity compromises the sensitivity and accuracy of this method. It is shown that under standard assay conditions, the ratio of the absorbance measurements at 590 nm and 450 nm is strictly linear with protein concentration. This simple procedure increases the accuracy and improves the sensitivity of the assay about 10-fold, permitting quantification down to 50 ng of bovine serum albumin. Furthermore, the interference commonly introduced by detergents that are used to create the cell lysates is greatly reduced by the new protocol. A linear equation developed on the basis of mass action and Beer's law perfectly fits the experimental data.

Contribution of FKBP5 genetic variation to gemcitabine treatment and survival in pancreatic adenocarcinoma.

Directory of Open Access Journals (Sweden)

Katarzyna A Ellsworth

Full Text Available FKBP51, (FKBP5, is a negative regulator of Akt. Variability in FKBP5 expression level is a major factor contributing to variation in response to chemotherapeutic agents including gemcitabine, a first line treatment for pancreatic cancer. Genetic variation in FKBP5 could influence its function and, ultimately, treatment response of pancreatic cancer.We set out to comprehensively study the role of genetic variation in FKBP5 identified by Next Generation DNA resequencing on response to gemcitabine treatment of pancreatic cancer by utilizing both tumor and germline DNA samples from 43 pancreatic cancer patients, including 19 paired normal-tumor samples. Next, genotype-phenotype association studies were performed with overall survival as well as with FKBP5 gene expression in tumor using the same samples in which resequencing had been performed, followed by functional genomics studies.In-depth resequencing identified 404 FKBP5 single nucleotide polymorphisms (SNPs in normal and tumor DNA. SNPs with the strongest associations with survival or FKBP5 expression were subjected to functional genomic study. Electromobility shift assay showed that the rs73748206 "A(T" SNP altered DNA-protein binding patterns, consistent with significantly increased reporter gene activity, possibly through its increased binding to Glucocorticoid Receptor (GR. The effect of rs73748206 was confirmed on the basis of its association with FKBP5 expression by affecting the binding to GR in lymphoblastoid cell lines derived from the same patients for whom DNA was used for resequencing.This comprehensive FKBP5 resequencing study provides insights into the role of genetic variation in variation of gemcitabine response.

Harmonization of radiobiological assays: why and how?

International Nuclear Information System (INIS)

Prasanna, Pataje G.

2014-01-01

The International Atomic Energy Agency has made available a technical manual for cytogenetic biodosimetry assays (dicentric chromosome aberration (DCA) and cytokinesis-block micronucleus (CBMN) assays) used for radiation dose assessment in radiation accidents. The International Standardization Organization, which develops standards and guidelines, also provides an avenue for laboratory accreditation, has developed guidelines and recommendations for performing cytogenetic biodosimetry assays. Harmonization of DCA and CBMN assays, has improved their accuracy. Double-blinded inter-laboratory comparison studies involving several networks have further validated DCA and CBMN assays and improved the confidence in their potential use for radiation dose assessment in mass casualties. This kind of international harmonization is lacking for pre-clinical radiobiology assays. The widely used pre-clinical assays that are relatively important to set stage for clinical trials include clonogenic assays, flow-cytometry assays, apoptotic assays, and tumor regression and growth delay assays. However, significant inter-laboratory variations occur with respect to data among laboratories. This raises concerns on the reliability and reproducibility of preclinical data that drives further development and translation. Lack of reproducibility may stem from a variety of factors such as poor scientist training, less than optimal experimental design, inadequate description of methodology, and impulse to publish only the positive data etc. Availability of technical manuals, standard operating procedures, accreditation avenues for laboratories performing such assays, inter-laboratory comparisons, and use of standardized protocols are necessary to enhance reliability and reproducibility. Thus, it is important that radiobiological assays are harmonized for laboratory protocols to ensure successful translation of pre-clinical research on radiation effect modulators to help design clinic trials with

Sperm DNA quality evaluated by comet assay and sperm chromatin structure assay in stallions after unilateral orchiectomy.

Science.gov (United States)

Serafini, R; Varner, D D; Bissett, W; Blanchard, T L; Teague, S R; Love, C C

2015-09-15

Unilateral orchiectomy (UO) may interfere with thermoregulation of the remaining testis caused by inflammation surrounding the incision site, thus altering normal spermatogenesis and consequently sperm quality. Two measures of sperm DNA quality (neutral comet assay and the sperm chromatin structure assay [SCSA]) were compared before UO (0 days) and at 14, 30, and 60 days after UO to determine whether sperm DNA changed after a mild testis stress (i.e., UO). The percent DNA in the comet tail was higher at 14 and 60 days compared to 0 days (P comet tail measures (i.e., length, moment, migration) were higher at all time periods after UO compared to 0 days (P comet assay and the SCSA, which was not identified using traditional measures of sperm quality. Copyright © 2015 Elsevier Inc. All rights reserved.

The diagnostic value of the fibrinogen/fibrin fragment E antigen assay in clinically suspected deep vein thrombosis

International Nuclear Information System (INIS)

Zielinsky, A.; Hirsh, J.; Straumanis, G.; Carter, C.J.; Gent, M.; Sackett, D.L.; Hull, R.; Kelton, J.G.; Powers, P.; Turpie, A.G.

1982-01-01

We have evaluated the fibrinogen/fibrin fragment E antigen assay as a diagnostic test in patients with clinically suspected venous thrombosis by comparing the results of this assay with venography in 272 patients. The result of the fragment E antigen assay was elevated in 79 of 80 patients with positive venograms for recent venous thrombosis (sensitivity 99%) and within the normal range in 161 of 192 patients with normal venograms (specificity 84%). The fragment E assay was also evaluated in 130 medical and surgical controls without evidence of venous thrombosis by leg scanning and the test was found to be relatively nonspecific. However, in the patient group under study, a correct clinical diagnosis of no thrombosis, based on a normal fragment E result, was made in 161 of 162 cases (negative predictive value of 99%). Therefore, a normal test result effectively excludes a diagnosis of venous thrombosis in clinically symptomatic patients. The assay, as currently performed, is technically demanding and takes 24 hr to complete. Therefore, it will have to be simplified before it can be applied to clinical practice

The diagnostic value of the fibrinogen/fibrin fragment E antigen assay in clinically suspected deep vein thrombosis

International Nuclear Information System (INIS)

Zielinsky, A.; Hirsh, J.; Straumanis, G.; Carter, C.J.; Gent, M.; Sackett, D.L.; Hull, R.; Kelton, J.G.; Powers, P.

1982-01-01

We have evaluated the fibrinogen/fibrin fragment E antigen assay as a diagnostic test in patients with clinically suspected venous thrombosis by comparing the results of this assay with venography in 272 patients. The result of the fragment E antigen assay was elevated in 79 of 80 patients with positive venograms for recent venous thrombosis (sensitivity 99%) and within the normal range in 161 of 192 patients with normal venograms (specificity 84%). The fragment E assay was also evaluated in 130 medical and surgical controls without evidence of venous thrombosis by leg scanning and the test was found to be relatively nonspecific. However, in the patient group under study, a correct clinical diagnosis of no thrombosis, based on a normal fragment E result, was made in 161 of 162 cases (negative predictive value 99%). Therefore, a normal test result effectively excludes a diagnosis of venous thrombosis in clinically symptomatic patients. The assay, as currently performed, is technically demanding and takes 24 hr to complete. Therefore, it will have to be simplified before it can be applied to clinical practice

Radiometric microbiologic assay for the biologically active forms of niacin

International Nuclear Information System (INIS)

Kertcher, J.A.; Guilarte, T.R.; Chen, M.F.; Rider, A.A.; McIntyre, P.A.

1979-01-01

A radiometric microbiologic assay has been developed for the determination of niacin in biologic fluids. Lactobacillus plantarum produced 14 CO 2 from L-[U- 14 C] malic acid in quantities proportional to the amount of niacin present. The assay is specific for the biologically active forms of niacin in humans. Thirty normal hemolysates were analyzed and the values ranged from 13.0 to 17.8 μg niacin/ml RBC (mean = 15.27 +- 1.33 s.d.). Good recovery and reproducibility studies were obtained with this assay. On thirty blood samples, correlation was excellent between the radiometric and the conventional turbidimetric assays

Comet Assay in Cancer Chemoprevention.

Science.gov (United States)

Santoro, Raffaela; Ferraiuolo, Maria; Morgano, Gian Paolo; Muti, Paola; Strano, Sabrina

2016-01-01

The comet assay can be useful in monitoring DNA damage in single cells caused by exposure to genotoxic agents, such as those causing air, water, and soil pollution (e.g., pesticides, dioxins, electromagnetic fields) and chemo- and radiotherapy in cancer patients, or in the assessment of genoprotective effects of chemopreventive molecules. Therefore, it has particular importance in the fields of pharmacology and toxicology, and in both environmental and human biomonitoring. It allows the detection of single strand breaks as well as double-strand breaks and can be used in both normal and cancer cells. Here we describe the alkali method for comet assay, which allows to detect both single- and double-strand DNA breaks.

Reference cells and ploidy in the comet assay

Directory of Open Access Journals (Sweden)

Gunnar eBrunborg

2015-02-01

Full Text Available In the comet assay, single cells are analyzed with respect to their level of DNA damage. Discrimination of the individual cell or cell type based on DNA content, with concomitant scoring of the DNA damage, is useful since this may allow analysis of mixtures of cells. Different cells can then be characterized based on their ploidy, cell cycle stage, or genome size. We here describe two applications of such a cell type-specific comet assay: (i Testicular cell suspensions, analyzed on the basis of their ploidy during spermatogenesis; and (ii reference cells in the form of fish erythrocytes which can be included as internal standards to correct for inter-assay variations. With standard fluorochromes used in the comet assay, the total staining signal from each cell – whether damaged or undamaged – was found to be associated with the cell’s DNA content. Analysis of the fluorescence intensity of single cells is straightforward since these data are available in scoring systems based on image analysis. The analysis of testicular cell suspensions provides information on cell type specific composition, susceptibility to genotoxicants, and DNA repair. Internal reference cells, either untreated or carrying defined numbers of lesions induced by ionizing radiation, are useful for investigation of experimental factors that can cause variation in comet assay results, and for routine inclusion in experiments to facilitate standardization of methods and comparison of comet assay data obtained in different experiments or in different laboratories. They can also be used - in combination with a reference curve - to quantify the DNA lesions induced by a certain treatment. Fish cells of a range of genome sizes, both greater and smaller than human, are suitable for this purpose and they are inexpensive.

Evaluation of Normalization Methods on GeLC-MS/MS Label-Free Spectral Counting Data to Correct for Variation during Proteomic Workflows

Science.gov (United States)

Gokce, Emine; Shuford, Christopher M.; Franck, William L.; Dean, Ralph A.; Muddiman, David C.

2011-12-01

Normalization of spectral counts (SpCs) in label-free shotgun proteomic approaches is important to achieve reliable relative quantification. Three different SpC normalization methods, total spectral count (TSpC) normalization, normalized spectral abundance factor (NSAF) normalization, and normalization to selected proteins (NSP) were evaluated based on their ability to correct for day-to-day variation between gel-based sample preparation and chromatographic performance. Three spectral counting data sets obtained from the same biological conidia sample of the rice blast fungus Magnaporthe oryzae were analyzed by 1D gel and liquid chromatography-tandem mass spectrometry (GeLC-MS/MS). Equine myoglobin and chicken ovalbumin were spiked into the protein extracts prior to 1D-SDS- PAGE as internal protein standards for NSP. The correlation between SpCs of the same proteins across the different data sets was investigated. We report that TSpC normalization and NSAF normalization yielded almost ideal slopes of unity for normalized SpC versus average normalized SpC plots, while NSP did not afford effective corrections of the unnormalized data. Furthermore, when utilizing TSpC normalization prior to relative protein quantification, t-testing and fold-change revealed the cutoff limits for determining real biological change to be a function of the absolute number of SpCs. For instance, we observed the variance decreased as the number of SpCs increased, which resulted in a higher propensity for detecting statistically significant, yet artificial, change for highly abundant proteins. Thus, we suggest applying higher confidence level and lower fold-change cutoffs for proteins with higher SpCs, rather than using a single criterion for the entire data set. By choosing appropriate cutoff values to maintain a constant false positive rate across different protein levels (i.e., SpC levels), it is expected this will reduce the overall false negative rate, particularly for proteins with

A feasibility study of adenosine triphosphate-based chemotherapy response assay (ATP-CRA) as a chemosensitivity test for lung cancer.

Science.gov (United States)

Kang, Shin Myung; Park, Moo Suk; Chang, Joon; Kim, Se Kyu; Kim, Haeryoung; Shin, Dong-Hwan; Chung, Kyung Young; Kim, Dae Joon; Sohn, Joo Hyuk; Choi, Sung Ho; Kim, Jeongmi; Yoon, Eun Jin; Kim, Joo-Hang

2005-08-01

A chemosensitivity test can reflect the differences in responses of individual cancer patients to chemotherapeutic agents. The adenosine triphosphate-based chemotherapy response assay (ATP-CRA) is an accurate method, which does not require a large amount of tissue specimen. So far, no studies have evaluated the utility of the ATP-CRA in Korea. Therefore, we investigated the clinical usefulness of the ATP-CRA in 53 patients with lung cancer. Tumor tissues were obtained from bronchoscopic biopsies or surgical resections. The validity of ATP-CRA was assessed focusing on the success rate, experimental error level (intraassay mean coefficient of variation [CV]) and reproducibility. The overall success rate of ATP-CRA was 90.6% (48/53). Normal cells were effectively eliminated from the tumor tissues with the use of ficoll gradient centrifugation and immunomagnetic separation, which was confirmed using loss of heterozygosity analysis of the 3p deletion. The mean CV of ATP assays was 10.5+/-4.6%. The reproducibility of ATP assays was 94+/-3.8%. The results of the ATP assays were reported to physicians within 7 days of specimen collection. More than 6 anticancer drugs were tested on the tumor specimens obtained from bronchoscopic biopsies. The ATP-CRA is a stable, accurate and potentially practical chemosensitivity test in patients with lung cancer.

Effect of bilirubin on the spectrophotometric and radionuclide assay for serum angiotensin-converting enzyme

International Nuclear Information System (INIS)

Saxe, A.W.; Hollinger, M.A.; Essam, T.

1986-01-01

The effect of bilirubin on serum angiotensin-converting enzyme (ACE) activity was studied with spectrophotometric and radionuclide assays. In the spectrophotometric assay addition of bilirubin to normal serum from dog, mouse, and human produced a dose-related inhibition of ACE activity. A 50% decrease in human ACE activity was produced by the addition of approximately 250 mg/L in vitro. Serum from icteric patients with elevated bilirubin was also associated with a reduction in ACE activity in the spectrophotometric assay. A 50% decrease in ACE activity in these samples was associated with a serum bilirubin of approximately 220 mg/L. In the radionuclide assay, however, addition of bilirubin to normal human serum failed to reduce measured ACE activity. The use of a radionuclide assay for serum ACE in clinical samples offers the advantage of less interference from serum bilirubin

Development and Fit-for-Purpose Validation of a Soluble Human Programmed Death-1 Protein Assay.

Science.gov (United States)

Ni, Yan G; Yuan, Xiling; Newitt, John A; Peterson, Jon E; Gleason, Carol R; Haulenbeek, Jonathan; Santockyte, Rasa; Lafont, Virginie; Marsilio, Frank; Neely, Robert J; DeSilva, Binodh; Piccoli, Steven P

2015-07-01

Programmed death-1 (PD-1) protein is a co-inhibitory receptor which negatively regulates immune cell activation and permits tumors to evade normal immune defense. Anti-PD-1 antibodies have been shown to restore immune cell activation and effector function-an exciting breakthrough in cancer immunotherapy. Recent reports have documented a soluble form of PD-1 (sPD-1) in the circulation of normal and disease state individuals. A clinical assay to quantify sPD-1 would contribute to the understanding of sPD-1-function and facilitate the development of anti-PD-1 drugs. Here, we report the development and validation of a sPD-1 protein assay. The assay validation followed the framework for full validation of a biotherapeutic pharmacokinetic assay. A purified recombinant human PD-1 protein was characterized extensively and was identified as the assay reference material which mimics the endogenous analyte in structure and function. The lower limit of quantitation (LLOQ) was determined to be 100 pg/mL, with a dynamic range spanning three logs to 10,000 pg/mL. The intra- and inter-assay imprecision were ≤15%, and the assay bias (percent deviation) was ≤10%. Potential matrix effects were investigated in sera from both normal healthy volunteers and selected cancer patients. Bulk-prepared frozen standards and pre-coated Streptavidin plates were used in the assay to ensure consistency in assay performance over time. This assay appears to specifically measure total sPD-1 protein since the human anti-PD-1 antibody, nivolumab, and the endogenous ligands of PD-1 protein, PDL-1 and PDL-2, do not interfere with the assay.

A new semiquantitative radiometric opsonin assay

International Nuclear Information System (INIS)

Yamamura, M.; Valdimarsson, H.

1978-01-01

A new semiquantitative radiometric opsonin assay is described. It was found that the opsonin activity generated by incubating brewer's yeast, Saccharomyces cerevisiae, in medium containing less than 5% human serum was exclusively complement dependent. In contrast, C.albicans was effectively opsonized in the absence of complement. Antibodies and the early classical complement pathway did not contribute to the opsonization of S.cerevisiae and neither did C5-9. The brewer's yeast assay can therefore be used for measuring selectively the opsonizing capacity of the alternative pathway. Sera from approximately 7% of apparently healthy adult controls consistently failed to generate significant opsonin activity while 8 out of 26 patients with suspected immune deficiency of unknown cause were defective in this assay. All opsonin deficient sera so far tested had haemolytically normal alternative pathway and Factor B activity. (author)

Radiometric microbiologic assay for the biologically active forms of niacin

Energy Technology Data Exchange (ETDEWEB)

Kertcher, J.A.; Guilarte, T.R.; Chen, M.F.; Rider, A.A.; McIntyre, P.A.

1979-05-01

A radiometric microbiologic assay has been developed for the determination of niacin in biologic fluids. Lactobacillus plantarum produced /sup 14/CO/sub 2/ from L-(U-/sup 14/C) malic acid in quantities proportional to the amount of niacin present. The assay is specific for the biologically active forms of niacin in humans. Thirty normal hemolysates were analyzed and the values ranged from 13.0 to 17.8 ..mu..g niacin/ml RBC (mean = 15.27 +- 1.33 s.d.). Good recovery and reproducibility studies were obtained with this assay. On thirty blood samples, correlation was excellent between the radiometric and the conventional turbidimetric assays.

Concepts for the assay of unbound thyroxine (FT4) and thyroxine binding globulin (TBG)

International Nuclear Information System (INIS)

Odstrchel, G.; Hertl, W.; Ward, F.B.; Travis, K.; Lindner, R.E.; Mason, R.D.

1977-01-01

Two new concepts for the assay of thyroid related substances are presented. One assay (FT 4 ) is based on a kinetic measurement of T 4 as it desorbs from binder proteins onto solid-phase T 4 antibody. This reaction can be described by a second order rate equation; r = k (IMA) (FT 4 ). The assay is rapid (2 hours) and gives good agreement (sigma = 0.92) with equilibrium dialysis and a normal range of 0.9 - 2.3 ng/dl. This assay uses a small sample size (25 μl) and is unaffected by drugs such as aspirin and dilantin. Pregnant and estrogen treated women gave normal FT 4 values. A new method for the measurement of functionally active TEG is also presented. In this case the labeled T 4 is partitioned between bovine serum albumin and the patient's samples. The complex is then removed from solution by solid-phase anti-TBG. A curve remiscent of an immunoradiometric assay is obtained. The assay has a sensitivity of 4 μg/ml and is unaffected by aspirin, dilantin or the patient's T 4 concentrations. Correlation with 'rocket' electrophoresis is 0.90. The normal range was 20 +- 7 μg/ml with pregnant women giving values greater than 30 μg/ml. Five hereditary deficient patients gave a value equivalent to zero TBG concentration. (orig.) [de

Vascularity and grey-scale sonographic features of normal cervical lymph nodes: variations with nodal size

International Nuclear Information System (INIS)

Ying, Michael; Ahuja, Anil; Brook, Fiona; Metreweli, Constantine

2001-01-01

AIM: This study was undertaken to investigate variations in the vascularity and grey-scale sonographic features of cervical lymph nodes with their size. MATERIALS AND METHODS: High resolution grey-scale sonography and power Doppler sonography were performed in 1133 cervical nodes in 109 volunteers who had a sonographic examination of the neck. Standardized parameters were used in power Doppler sonography. RESULTS: About 90% of lymph nodes with a maximum transverse diameter greater than 5 mm showed vascularity and an echogenic hilus. Smaller nodes were less likely to show vascularity and an echogenic hilus. As the size of the lymph nodes increased, the intranodal blood flow velocity increased significantly (P 0.05). CONCLUSIONS: The findings provide a baseline for grey-scale and power Doppler sonography of normal cervical lymph nodes. Sonologists will find varying vascularity and grey-scale appearances when encountering nodes of different sizes. Ying, M. et al. (2001)

Pathologic evaluation of normal and perfused term placental tissue

DEFF Research Database (Denmark)

Maroun, Lisa Leth; Mathiesen, Line; Hedegaard, Morten

2014-01-01

This study reports for the 1st time the incidence and interobserver variation of morphologic findings in a series of 34 term placentas from pregnancies with normal outcome used for perfusion studies. Histologic evaluation of placental tissue is challenging, especially when it comes to defining...... "normal tissue" versus "pathologic lesions." A scoring system for registration of abnormal morphologic findings was developed. Light microscopic examination was performed independently by 2 pathologists, and interobserver variation was analyzed. Findings in normal and perfused tissue were compared...... and selected findings were tested against success parameters from the perfusions. Finally, the criteria for frequent lesions with fair to poor interobserver variation in the nonperfused tissue were revised and reanalyzed. In the perfused tissue, the perfusion artefact "trophoblastic vacuolization," which...

Effects of the oral, direct thrombin inhibitor dabigatran on five common coagulation assays.

Science.gov (United States)

Lindahl, Tomas L; Baghaei, Fariba; Blixter, Inger Fagerberg; Gustafsson, Kerstin M; Stigendal, Lennart; Sten-Linder, Margareta; Strandberg, Karin; Hillarp, Andreas

2011-02-01

Dabigatran is an oral, reversible thrombin inhibitor that has shown promising results in large clinical trials. Laboratory monitoring is not needed but the effects on common coagulation assays are incompletely known. Dabigatran was added to plasma from healthy subjects in the concentration range 0-1,000 μg/l and analysed using several reagents for activated thromboplastin time (APTT), prothrombin time (PT), fibrinogen, antithrombin, and activated protein C resistance. Typical trough concentrations are about 50 μg/l, peak concentrations 100-300 μg/l. At 100 μg/l all APTT-results were prolonged. The concentration required to double APTT ranged between 227 and 286 μg/l, the responses for all five reagents were similar. PT-reagents were much less affected with almost no samples above INR 1.2 at 100 μg/l. The effect was sample dilution dependent with PT Quick type more sensitive than PT Owren type methods. If a patient on dabigatran has prolonged APTT, >90 seconds, and Quick PT INR>2 or Owren PT INR>1.5 over-dosing or accumulation of dabigatran should be considered. Two of four fibrinogen reagents underestimated the fibrinogen concentration considerably at expected peak concentration. Methods based on inhibition of thrombin over-estimated the antithrombin concentration, but not Xa-based. The APC-resistance methods over-estimated the APC-ratio, which may lead to miss-classification of factor V Leiden patients as being normal. Different coagulation assays, and even different reagents within an assay group, display variable effects at therapeutic concentrations of dabigatran. Some of these assay variations are of clinical importance, thus knowledge is needed for a correct interpretation of results.

Normal human bone marrow and its variations in MRI

International Nuclear Information System (INIS)

Vahlensieck, M.; Schmidt, H.M.

2000-01-01

Physiology and age dependant changes of human bone marrow are described. The resulting normal distribution patterns of active and inactive bone marrow including the various contrasts on different MR-sequences are discussed. (orig.) [de

Radioligand assay for biotin in liver tissues

International Nuclear Information System (INIS)

Rettenmaier, R.

1979-01-01

A radioligand assay for biotin in liver tissue is described. 3 H-biotin is used as tracer and avidin as binder. The biotin-loaded avidin is separated from free biotin on dextran-coated charcoal, which leaves the avidin-biotin complex in the supernatant liquid. Thus, the avidin-biotin complex can easily be utilized for determination of the radioactivity. Calibration with known additions of biotin in the range 0.25-8.0 ng per assay sample yields a linear logit-log plot. The biotin is extracted from liver tissues by enzymatic proteolysis with papain. This treatment is optimized to liberate the bound forms of the vitamin. Microbiological parallel assays with Lactobacillus plantarum were in good agreement with the radioligand assay giving a regression coefficient of 0.974(n=44). The coefficient of variation was found to be 4.2% in the range 500-1200 ng of biotin per g of liver tissue (n=46). The method is simple and reliable and allows the simultaneous analysis of a considerable number of samples. (Auth.)

Normalization matters: tracking the best strategy for sperm miRNA quantification.

Science.gov (United States)

Corral-Vazquez, Celia; Blanco, Joan; Salas-Huetos, Albert; Vidal, Francesca; Anton, Ester

2017-01-01

biological processes. Hsa-miR-146b-5p and hsa-miR-92a-3p were more uniformly expressed than RNU6B, but their results still showed scant proximity to the reference method. The highest resemblance to MCR was achieved by hsa-miR-100-5p and hsa-miR-30a-5p. Normalization against the combination of both miRNAs reached the best proximity rank regarding the detected DE-miRNAs (Area Under the Curve = 0.8). This combination also exhibited the best performance in terms of the target genes predicted (72.3% of True Positives) and their corresponding enriched biological processes (70.4% of True Positives). Not applicable. This study is focused on sperm miRNA qRT-PCR analysis. The use of the selected normalizers in other cell types or tissues would still require confirmation. The search for new fertility biomarkers based on sperm miRNA expression using high-throughput assays is one of the upcoming challenges in the field of reproductive genetics. In this context, validation of the results using singleplex assays would be mandatory. The normalizer strategy suggested in this study would provide a universal option in this area, allowing for normalization of the validated data without causing meaningful variations of the results. Instead, qRT-PCR data normalization by RNU6B should be discarded in sperm-miRNA expression studies. This work was supported by the 2014/SGR00524 project (Agència de Gestió d'Ajuts Universitaris i de Recerca, Generalitat de Catalunya, Spain) and UAB CF-180034 grant (Universitat Autònoma de Barcelona). Celia Corral-Vazquez is a recipient of a Personal Investigador en Formació grant UAB/PIF2015 (Universitat Autònoma de Barcelona). The authors report no conflict of interest. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Investigation of parameters that affect the success rate of microarray-based allele-specific hybridization assays.

Directory of Open Access Journals (Sweden)

Lena Poulsen

Full Text Available BACKGROUND: The development of microarray-based genetic tests for diseases that are caused by known mutations is becoming increasingly important. The key obstacle to developing functional genotyping assays is that such mutations need to be genotyped regardless of their location in genomic regions. These regions include large variations in G+C content, and structural features like hairpins. METHODS/FINDINGS: We describe a rational, stable method for screening and combining assay conditions for the genetic analysis of 42 Phenylketonuria-associated mutations in the phenylalanine hydroxylase gene. The mutations are located in regions with large variations in G+C content (20-75%. Custom-made microarrays with different lengths of complementary probe sequences and spacers were hybridized with pooled PCR products of 12 exons from each of 38 individual patient DNA samples. The arrays were washed with eight buffers with different stringencies in a custom-made microfluidic system. The data were used to assess which parameters play significant roles in assay development. CONCLUSIONS: Several assay development methods found suitable probes and assay conditions for a functional test for all investigated mutation sites. Probe length, probe spacer length, and assay stringency sufficed as variable parameters in the search for a functional multiplex assay. We discuss the optimal assay development methods for several different scenarios.

Fibroblast radiosensitivity versus acute and late normal skin responses in patients treated for breast cancer

International Nuclear Information System (INIS)

Brock, W.A.; Wike, J.; Tucker, S.L.

1995-01-01

To determine if the radiosensitivity of normal human skin fibroblasts, measured in early passage cultures, is significantly correlated with the degree of acute or late normal skin damage in patients treated for breast cancer with radiotherapy. To test assay reproducibility, SF2 values derived from paired biopsies of the same patient (12 cases) were compared. A reasonably good correlation (p = 0.075) was obtained for SF2s determined by high dose-rate irradiations with immediated plating, but not for delayed plating or low dose-rate treatments. The median coefficient of variation in the replicate SF2s after high dose-rate treatment and immediate plating was 13%, suggesting that the poor correlation in paired SF2 values is due to the magnitude of the uncertainty in SF2 relative to the overall spread in SF2 values between patients (CV = 28%). Individual SF2 values and averaged values from patients with data from two biopsies were compared with the acute and late clinical reactions. A significant negative correlation was found between SF2 and relative clinical response, but only when averaged high dose-rate SF2 values and telangiectasia scores were compared. There was no significant correlation between average SF2 values and acute responses or between individual SF2 measurements and either the acute or late clinical response. The results of this study suggest that the degree of late telangiectasia is at least partially dependent upon the intrinsic cellular radiosensitivity of normal fibroblasts, but the relationship is not clear cut. Multiple replicate assays are necessary to obtain reliable estimates of fibroblast SF2 values using current techniques. 20 refs., 3 figs., 3 tabs

A comparison of sperm agglutination and immobilization assays with a quantitative ELISA for anti-sperm antibody in serum.

Science.gov (United States)

Lynch, D M; Leali, B A; Howe, S E

1986-08-01

An enzyme-linked immunosorbent assay (ELISA) that quantitates antisperm antibody in serum was compared with standard sperm agglutination and immobilization assays with the use of sera from 40 normal and 292 subfertile individuals. Quantitation of the assay was accomplished by standardizing assay parameters, including the incorporation of a standard reference curve, the number of whole target sperm, the optimal dilution of serum, the selection of microtiter plate, and the time and temperatures involved in the adsorption and incubation phases. With this method, the level of antisperm antibody binding to target sperm in 40 normal fertile individuals was found to be 2.3 (+/- 1.1 standard deviation [SD]) fg immunoglobulin (Ig)/sperm. An increased mean level of 7.4 +/- 3.7 fg Ig/sperm was determined in 84 infertile patients with positive agglutination and/or immobilization tests. In 208 individuals with negative agglutination and immobilization tests the mean concentration of antisperm antibody was 2.5 +/- 1.3 fg Ig/sperm. Postvasectomy patients assayed by this method had a mean Ig binding value of 7.1 +/- 2.4 fg Ig/sperm. The infertile group with positive agglutination and/or immobilization tests had a significantly higher mean antisperm antibody level than the normal fertile group, according to the Student's t-test for independent samples (P less than 0.001). This indirect serum-based assay reproducibly quantitates antisperm antibody binding to whole target sperm, suggests the normal and abnormal levels of antisperm antibody, and correlates with standard functional assays.

Measurement of thyroid-stimulating autoantibodies using a radioreceptor-assay (TRAK-assay)

International Nuclear Information System (INIS)

Becker, W.; Reiners, C.; Boerner, W.

1983-01-01

Autoantibodes against TSH-receptors were determined with a new radioreceptorassay (TRAK-assay) in 37 patients with untreated toxic diffus goitre and in 73 patients with non immunogenic thyroid diseases (41 healthy controls, respectively patients with euthyroid diffus or nodular goitres as well as 32 patients with toxic nodular goitre). The upper limit of normal is a TRAK-Titer of 20% without considerable fluctuations during titers in follow-up. According to this preliminary results it seems to be recommendable to treat patients with TRAK-titer F 20% (expected risk of relapse) primarily by operation or radioiodine. (orig.) [de

Assembling of (βLPH) beta-lypothrophine radioimmunoassay. Plasma levels standardization in normal individuals and patients with hypophysis and adrenals diseases

International Nuclear Information System (INIS)

Castro, Margaret de.

1988-01-01

The present study investigates the extraction and radioimmunoassay (RIA) conditions of plasma βLPH. It was extracted by the activated silicic acid method, with a mean extraction efficiency of 31.6% and a mean intra-extraction variation coefficient of 8.1%. Radioiodination was performed by the chloramine-T method and βLPH 125 I was purified by gel chromatography on Sephadex G100. Estimated specific activity ranged from 100 to 192.8 μCi/μg, with a mean incorporation percentage of 66.6%. The titer of the first antibody was 1:50.000/100 μl. The assay was performed under non-equilibrium conditions, with a pre-incubation period of 24 hours and incubation of 4 hours. Mean immunoreactivity (Bo/Total) was 21.1%, with a mean Blank/Total ratio of 2.3%. Sensitivity, expressed as the mean minimum detectable dose, was 40 pg/tube, equivalent to 56 pg/ml plasma. Intra-assay variation coefficients were 6.5%, 3.8% and 6.8%, respectively, at B/Bo levels of 0.8, 0.6 and 0.4 of the standard curve. At B/Bo equal to 0.5, the intra-assay variation coefficient was 20.9%. Replicates of 14 plasma samples showed a correlation coefficient of r 0.99, (p< 0.05). Parallelism between the curve obtained with different volumes of an extract with a high βLPH value and the standard curve was found. The method was controlled biologically by the presence of correlation between the plasma βLPH levels and determined pathological states and with clinical functional studies. Twenty seven normal individuals, 10 patients with Cushing's disease to a tumor of the hypophysis, 4 patients with Cushing syndrome due to an adrenal tumor, 10 patients Addison disease, and 8 patients with hypopituitarism were studied. (author). 119 refs., 28 figs., 2 tabs

Correlation of in vitro lymphocyte radiosensitivity and gene expression with late normal tissue reactions following curative radiotherapy for breast cancer

International Nuclear Information System (INIS)

Finnon, Paul; Kabacik, Sylwia; MacKay, Alan; Raffy, Claudine; A’Hern, Roger; Owen, Roger; Badie, Christophe; Yarnold, John; Bouffler, Simon

2012-01-01

Background and purpose: Identification of mechanisms of late normal tissue responses to curative radiotherapy that discriminate individuals with marked or mild responses would aid response prediction. This study aimed to identify differences in gene expression, apoptosis, residual DNA double strand breaks and chromosomal damage after in vitro irradiation of lymphocytes in a series of patients with marked (31 cases) or mild (28 controls) late adverse reaction to adjuvant breast radiotherapy. Materials and methods: Gene expression arrays, residual γH2AX, apoptosis, G2 chromosomal radiosensitivity and G0 micronucleus assay were used to compare case and control lymphocyte radiation responses. Results: Five hundred and thirty genes were up-regulated and 819 down-regulated by ionising radiation. Irradiated samples were identified with an overall cross-validated error rate of 3.4%. Prediction analyses to classify cases and controls using unirradiated (0 Gy), irradiated (4 Gy) or radiation response (4–0 Gy) expression profiles correctly identified samples with, respectively, 25%, 22% or 18.5% error rates. Significant inter-sample variation was observed for all cellular endpoints but cases and controls could not be distinguished. Conclusions: Variation in lymphocyte radiosensitivity does not necessarily correlate with normal tissue response to radiotherapy. Gene expression analysis can predict of radiation exposure and may in the future help prediction of normal tissue radiosensitivity.

A versatile, high through-put, bead-based phagocytosis assay for Plasmodium falciparum

DEFF Research Database (Denmark)

Lloyd, Yukie M.; Ngati, Elise P.; Salanti, Ali

2017-01-01

Antibody-mediated phagocytosis is an important immune effector mechanism against Plasmodium falciparum-infected erythrocytes (IE); however, current phagocytosis assays use IE collected from infected individuals or from in vitro cultures of P. falciparum, making them prone to high variation....... A simple, high-throughput flow cytometric assay was developed that uses THP-1 cells and fluorescent beads covalently-coupled with the malarial antigen VAR2CSA. The assay is highly repeatable, provides both the overall percent phagocytosis and semi-quantitates the number of antigen-coupled beads...

Comparison of the direct enzyme assay method with the membrane ...

African Journals Online (AJOL)

Comparison of the direct enzyme assay method with the membrane filtration technique in the quantification and monitoring of microbial indicator organisms – seasonal variations in the activities of coliforms and E. coli, temperature and pH.

Renal function and plasma dabigatran level measured at trough by diluted thrombin time assay

Directory of Open Access Journals (Sweden)

Marta E. Martinuzzo

2017-02-01

Full Text Available Dabigatran etexilate (direct thrombin inhibitor is effective in preventing embolic stroke in patients with atrial fibrillation. It does not require laboratory control, but given the high renal elimination, its measurement in plasma is important in renal failure. The objectives of the study were to verify the analytical quality of the diluted thrombin time assay for measurement of dabigatran plasma concentration (cc, correlate cc with classic coagulation assays, prothrombin time (PT and activated partial thromboplastin time (APTT, and evaluate them according to the creatinine clearance (CLCr. Forty plasma samples of patients (34 consecutive and 6 suspected of drug accumulation receiving dabigatran at 150 (n = 19 or 110 (n = 21 mg/12 hours were collected. Blood samples were drawn at 10-14 hours of the last intake. Dabigatran concentration was determined by diluted thrombin time (HemosIl DTI, Instrumentation Laboratory (IL. PT and APTT (IL were performed on two fotooptical coagulometers, ACL TOP 300 and 500 (IL. DTI presented intra-assay coefficient of variation < 5.4% and inter-assay < 6%, linearity range 0-493 ng/ml. Patients' cc: median 83 (4-945 ng/ml. Individuals with CLCr in the lowest tertile (22.6-46.1 ml/min showed significantly higher median cc: 308 (49-945, compared to the average 72 (12-190 and highest tertile, 60 (4-118 ng/ml. Correlation between cc and APTT or PT were moderate, r2 = 0.59 and -0.66, p < 0.0001, respectively. DTI test allowed us to quantify plasma dabigatran levels, both in patients with normal or altered renal function, representing a useful tool in clinical situations such as renal failure, pre surgery or emergencies

On normal modes in classical Hamiltonian systems

NARCIS (Netherlands)

van Groesen, Embrecht W.C.

1983-01-01

Normal modes of Hamittonian systems that are even and of classical type are characterized as the critical points of a normalized kinetic energy functional on level sets of the potential energy functional. With the aid of this constrained variational formulation the existence of at least one family

Site, gender and age variation in normal skin colour on the back and the forearm: tristimulus colorimeter measurements.

Science.gov (United States)

Fullerton, A; Serup, J

1997-02-01

To study whether anatomical location and age and gender of subjects had any influence on the objective skin colour measurements. Baseline colour in prone position was measured with the Minolta ChromaMeter® in the upper, middle and lower level of the upper back and on the forearm of 168 volunteers. These two sites are commonly used in skin testing. Higher basal a* and lower basal L* levels were found on the upper scapular region compared to the lower scapular region and the subscapular region. The basal b* level showed no variation relative to site. The basal a* and the basal b* levels were lower on the forearm compared to the upper back while the basal L* level was higher. Females above 65 years showed a less coloured skin with lower values as compared to those of younger age. Females were found to have a generally lower basal a* level than males both on the upper back and forearm skin. These relatively major differences and sources of variation have to be considered when planning irritancy studies where colour differences between erythema and normal skin is used.

Chromogenic Factor VIII Assays for Improved Diagnosis of Hemophilia A.

Science.gov (United States)

Rodgers, Susan; Duncan, Elizabeth

2017-01-01

Hemophilia A is an inherited bleeding disorder caused by a reduced level of factor VIII coagulant activity (FVIII:C) in blood. Bleeding episodes may occur spontaneously in the severe form of hemophilia or after trauma in the milder forms. It is important that patients are diagnosed correctly, which includes placing them into the correct severity category of the disorder so that appropriate treatment can be given. Diagnosis is made by determination of the amount of FVIII:C in the blood, usually using a one-stage factor VIII:C assay. However, approximately one third of patients with mild or moderate hemophilia will have much lower results by the chromogenic assay, with some of them having normal results by the one-stage assay. The chromogenic factor VIII assay is used in some specialized hemophilia reference centers and is recommended for the diagnosis of mild hemophilia A, as this assay is considered to better reflect the severity status of hemophilia patients than the one-stage assay.

Chromosomal radiosensitivity: a study of the chromosomal G2 assay in human blood lymphocytes indicating significant inter-individual variability

International Nuclear Information System (INIS)

Smart, V.; Curwen, G.B.; Whitehouse, C.A.; Edwards, A.; Tawn, E.J.

2003-01-01

The G 2 chromosomal radiosensitivity assay is a technically demanding assay. To ensure that it is reproducible in our laboratory, we have examined the effects of storage and culture conditions by applying the assay to a group of healthy controls and determined the extent of intra- and inter-individual variations. Nineteen different individuals provided one or more blood samples resulting in a total of 57 successful tests. Multiple cultures from a single blood sample showed no statistically significant difference in the number of chromatid type aberrations between cultures. A 24 h delay prior to culturing the lymphocytes did not significantly affect the induced G 2 score. Intra-individual variation was not statistically significant in seven out of nine individuals. Inter-individual variation was highly statistically significant (P<0.001), indicating that there is a real difference between individuals in the response to radiation using this assay

DNA copy number, including telomeres and mitochondria, assayed using next-generation sequencing

Directory of Open Access Journals (Sweden)

Jackson Stuart

2010-04-01

Full Text Available Abstract Background DNA copy number variations occur within populations and aberrations can cause disease. We sought to develop an improved lab-automatable, cost-efficient, accurate platform to profile DNA copy number. Results We developed a sequencing-based assay of nuclear, mitochondrial, and telomeric DNA copy number that draws on the unbiased nature of next-generation sequencing and incorporates techniques developed for RNA expression profiling. To demonstrate this platform, we assayed UMC-11 cells using 5 million 33 nt reads and found tremendous copy number variation, including regions of single and homogeneous deletions and amplifications to 29 copies; 5 times more mitochondria and 4 times less telomeric sequence than a pool of non-diseased, blood-derived DNA; and that UMC-11 was derived from a male individual. Conclusion The described assay outputs absolute copy number, outputs an error estimate (p-value, and is more accurate than array-based platforms at high copy number. The platform enables profiling of mitochondrial levels and telomeric length. The assay is lab-automatable and has a genomic resolution and cost that are tunable based on the number of sequence reads.

Micropatterned comet assay enables high throughput and sensitive DNA damage quantification.

Science.gov (United States)

Ge, Jing; Chow, Danielle N; Fessler, Jessica L; Weingeist, David M; Wood, David K; Engelward, Bevin P

2015-01-01

The single cell gel electrophoresis assay, also known as the comet assay, is a versatile method for measuring many classes of DNA damage, including base damage, abasic sites, single strand breaks and double strand breaks. However, limited throughput and difficulties with reproducibility have limited its utility, particularly for clinical and epidemiological studies. To address these limitations, we created a microarray comet assay. The use of a micrometer scale array of cells increases the number of analysable comets per square centimetre and enables automated imaging and analysis. In addition, the platform is compatible with standard 24- and 96-well plate formats. Here, we have assessed the consistency and sensitivity of the microarray comet assay. We showed that the linear detection range for H2O2-induced DNA damage in human lymphoblastoid cells is between 30 and 100 μM, and that within this range, inter-sample coefficient of variance was between 5 and 10%. Importantly, only 20 comets were required to detect a statistically significant induction of DNA damage for doses within the linear range. We also evaluated sample-to-sample and experiment-to-experiment variation and found that for both conditions, the coefficient of variation was lower than what has been reported for the traditional comet assay. Finally, we also show that the assay can be performed using a 4× objective (rather than the standard 10× objective for the traditional assay). This adjustment combined with the microarray format makes it possible to capture more than 50 analysable comets in a single image, which can then be automatically analysed using in-house software. Overall, throughput is increased more than 100-fold compared to the traditional assay. Together, the results presented here demonstrate key advances in comet assay technology that improve the throughput, sensitivity, and robustness, thus enabling larger scale clinical and epidemiological studies. © The Author 2014. Published by

An atlas of normal skeletal scintigraphy

International Nuclear Information System (INIS)

Flanagan, J.J.; Maisey, M.N.

1985-01-01

This atlas was compiled to provide the neophyte as well as the experienced radiologist and the nuclear medicine physician with a reference on normal skeletal scintigraphy as an aid in distinguishing normal variations in skeletal uptake from abnormal findings. Each skeletal scintigraph is labeled, and utilizing an identical scale, a relevant skeletal photograph and radiograph are placed adjacent to the scintigraph

NORMAL AXIAL ANGLES OF THE KNEE JOINT IN ADULT ...

African Journals Online (AJOL)

hi-tech

2003-08-01

Aug 1, 2003 ... Conclusion: Our study has demonstrated comparative variations in means and ranges of normal axial angles .... population was significantly different from the mean ... case, however, the angle also exhibits racial variations.

A systematic evaluation of normalization methods in quantitative label-free proteomics.

Science.gov (United States)

Välikangas, Tommi; Suomi, Tomi; Elo, Laura L

2018-01-01

To date, mass spectrometry (MS) data remain inherently biased as a result of reasons ranging from sample handling to differences caused by the instrumentation. Normalization is the process that aims to account for the bias and make samples more comparable. The selection of a proper normalization method is a pivotal task for the reliability of the downstream analysis and results. Many normalization methods commonly used in proteomics have been adapted from the DNA microarray techniques. Previous studies comparing normalization methods in proteomics have focused mainly on intragroup variation. In this study, several popular and widely used normalization methods representing different strategies in normalization are evaluated using three spike-in and one experimental mouse label-free proteomic data sets. The normalization methods are evaluated in terms of their ability to reduce variation between technical replicates, their effect on differential expression analysis and their effect on the estimation of logarithmic fold changes. Additionally, we examined whether normalizing the whole data globally or in segments for the differential expression analysis has an effect on the performance of the normalization methods. We found that variance stabilization normalization (Vsn) reduced variation the most between technical replicates in all examined data sets. Vsn also performed consistently well in the differential expression analysis. Linear regression normalization and local regression normalization performed also systematically well. Finally, we discuss the choice of a normalization method and some qualities of a suitable normalization method in the light of the results of our evaluation. © The Author 2016. Published by Oxford University Press.

A three-layer immunoradiometric assay for determination of IgG subclass antibodies in Human Sera (''IgG subclass RAST'')

International Nuclear Information System (INIS)

Djurup, R.; Soendergaard, I.; Weeke, B.; University of Copenhagen, Denmark); Magnusson, C.G.M.

1984-01-01

We report the development of a three-layer immunoradiometric assay (TIRA) for measurement of IgG antibodies of all four subclasses in human sera. The first layer consists of diluted human serum, the second layer is monoclonal mouse antibodies to human IgG subclasses, and the third layer is 125 I-labelled rabbit anti-mouse IgG. Monoclonal anti-IgGI, anti-IgG3 and anti-IgG4 reacted only with their complementary IgG subclass, whereas the anti-IgG2 showed slight cross-reactivity to immunoglobins of other subclasses and classes and to light chain proteins. The observed cross-reactivity was found to be without importance, when the TIRA was applied to measurement of IgG subclass antibodies. Equipotency was established by use of appropriate dilutions of the monoclonal antibodies, and the assay was calibrated by use of human reference serum. The TIRA therefore permits reliable inter-individual and intra-individual comparisons of the IgG antibody response in all four subclasses. Non-specific binding obtained with pooled normal human serum was below 0.33%. Inter-assay coefficient of variation was between 18 and 27%. The TIRA was applied to measurement of IgG subclass antibodies to timothy grass pollen in sera from grass pollen allergies undergoing immunotherapy. (author)

Improving the scaling normalization for high-density oligonucleotide GeneChip expression microarrays

Directory of Open Access Journals (Sweden)

Lu Chao

2004-07-01

Full Text Available Abstract Background Normalization is an important step for microarray data analysis to minimize biological and technical variations. Choosing a suitable approach can be critical. The default method in GeneChip expression microarray uses a constant factor, the scaling factor (SF, for every gene on an array. The SF is obtained from a trimmed average signal of the array after excluding the 2% of the probe sets with the highest and the lowest values. Results Among the 76 U34A GeneChip experiments, the total signals on each array showed 25.8% variations in terms of the coefficient of variation, although all microarrays were hybridized with the same amount of biotin-labeled cRNA. The 2% of the probe sets with the highest signals that were normally excluded from SF calculation accounted for 34% to 54% of the total signals (40.7% ± 4.4%, mean ± sd. In comparison with normalization factors obtained from the median signal or from the mean of the log transformed signal, SF showed the greatest variation. The normalization factors obtained from log transformed signals showed least variation. Conclusions Eliminating 40% of the signal data during SF calculation failed to show any benefit. Normalization factors obtained with log transformed signals performed the best. Thus, it is suggested to use the mean of the logarithm transformed data for normalization, rather than the arithmetic mean of signals in GeneChip gene expression microarrays.

Single-cell microgel electrophoresis: an in vitro assay of radiosensitivity

International Nuclear Information System (INIS)

Deeley, J.O.T.; Moore, J.L.

1993-01-01

The results obtained by a microgel electrophoresis are comparable to conventional gel electrophoresis and elution techniques (Singh et al, 1989), DNA precipitation, alkali unwinding and cell clonogenicity assays (Olive et al, 1990). Since single cells are assessed, microgel electrophoresis is particularly appropriate for end-points such as the intercell variation in response. The simplicity, low cost and rapidity of microgel electrophoresis compared with other assays makes it particularly attractive for assessing the effects on DNA of radiation and other genotoxic agents on the general population. (Author)

Multicenter Evaluation of Cystatin C Measurement after Assay Standardization.

Science.gov (United States)

Bargnoux, Anne-Sophie; Piéroni, Laurence; Cristol, Jean-Paul; Kuster, Nils; Delanaye, Pierre; Carlier, Marie-Christine; Fellahi, Soraya; Boutten, Anne; Lombard, Christine; González-Antuña, Ana; Delatour, Vincent; Cavalier, Etienne

2017-04-01

Since 2010, a certified reference material ERM-DA471/IFCC has been available for cystatin C (CysC). This study aimed to assess the sources of uncertainty in results for clinical samples measured using standardized assays. This evaluation was performed in 2015 and involved 7 clinical laboratories located in France and Belgium. CysC was measured in a panel of 4 serum pools using 8 automated assays and a candidate isotope dilution mass spectrometry reference measurement procedure. Sources of uncertainty (imprecision and bias) were evaluated to calculate the relative expanded combined uncertainty for each CysC assay. Uncertainty was judged against the performance specifications derived from the biological variation model. Only Siemens reagents on the Siemens systems and, to a lesser extent, DiaSys reagents on the Cobas system, provided results that met the minimum performance criterion calculated according to the intraindividual and interindividual biological variations. Although the imprecision was acceptable for almost all assays, an increase in the bias with concentration was observed for Gentian reagents, and unacceptably high biases were observed for Abbott and Roche reagents on their own systems. This comprehensive picture of the market situation since the release of ERM-DA471/IFCC shows that bias remains the major component of the combined uncertainty because of possible problems associated with the implementation of traceability. Although some manufacturers have clearly improved their calibration protocols relative to ERM-DA471, most of them failed to meet the criteria for acceptable CysC measurements. © 2016 American Association for Clinical Chemistry.

Radioimmune assay of human platelet prostaglandin synthetase

International Nuclear Information System (INIS)

Roth, G.J.; Machuga, E.T.

1982-01-01

Normal platelet function depends, in part, on platelet PG synthesis. PG synthetase (cyclo-oxygenase) catalyzes the first step in PG synthesis, the formation of PGH 2 from arachidonic acid. Inhibition of the enzyme by ASA results in an abnormality in the platelet release reaction. Patients with pparent congenital abnormalities in the enzyme have been described, and the effects have been referred to as ''aspirin-like'' defects of the platelet function. These patients lack platelet PG synthetase activity, but the actual content of PG synthetase protein in these individuals' platelets is unknown. Therefore an RIA for human platelet PG synthetase would provide new information, useful in assessing the aspirin-like defects of platelet function. An RIA for human platelet PG synthetase is described. The assay utilizes a rabbit antibody directed against the enzyme and [ 125 I]-labelled sheep PG synthetase as antigen. The human platelet enzyme is assayed by its ability to inhibit precipitation of the [ 125 I]antigen. The assay is sensitive to 1 ng of enzyme. By the immune assay, human platelets contain approximately 1200 ng of PG synethetase protein per 1.5 mg of platelet protein (approximately 10 9 platelets). This content corresponds to 10,000 enzyme molecules per platelet. The assay provides a rapid and convenient assay for the human platelet enzyme, and it can be applied to the assessment of patients with apparent platelet PG synthetase (cyclo-oxygenase) deficiency

Detection of radiation-induced apoptosis using the comet assay

International Nuclear Information System (INIS)

Wada, Seiichi; Kobayashi, Yasuhiko; Funayama, Tomoo; Yamamoto, Kazuo; Khoa, Tran Van; Natsuhori, Masahiro; Ito, Nobuhiko

2003-01-01

The electrophoresis pattern of apoptotic cells detected by the comet assay has a characteristic small head and spread tail. This image has been referred to as an apoptotic comet, but it has not been previously proven to be apoptotic cells by any direct method. In order to identify this image obtained by the comet assay as corresponding to an apoptotic cell, the frequency of appearance of apoptosis was examined using CHO-K1 and L5178Y cells which were exposed to gamma irradiation. As a method for detecting apoptosis, the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay was used. When the frequency of appearance of apoptotic cells following gamma irradiation was observed over a period of time, there was a significant increase in appearance of apoptosis when using the TUNEL assay. However, there was only a slight increase when using the comet assay. In order to verify the low frequency of appearance of apoptosis when using the comet assay, we attempted to use the TUNEL assay to satin the apoptotic comets detected in the comet assay. The apoptotic comets were TUNEL positive and the normal comets were TUNEL negative. This indicates that the apoptotic comets were formed from DNA fragments with 3'-hydroxy ends that are generated as cells undergo apoptosis. Therefore, it was understood that the characteristic pattern of apoptotic comets detected by the comet assay corresponds to cells undergoing apoptosis. (author)

Comparative study cephalometric-radiographic of the cephalo-facio-dental patterns in patients who presented normal occlusion and class II, division 1 malocclusions, considering variations of the FMA angle

International Nuclear Information System (INIS)

David, S.M.N.

1986-01-01

The proposal of this job was to study cephalo-facio-dental patterns comparatively in patients who presented normal occlusion and Class II, division 1 malocclusions, considering variations of the FMA angle. The sample was composed of seventy-five telerradiographies on lateral pattern, obtained from Brazilian teenagers students of the ABC area (Santo Andre, Sao Bernardo do Campo and Sao Caetano do Sul), 'whites', who presented normal occlusion and Class II, division 1 malocclusions, without previous orthodontic treatment: their parents were Brazilian. (author) [pt

SU-E-T-427: Cell Surviving Fractions Derived From Tumor-Volume Variation During Radiotherapy for Non-Small Cell Lung Cancer: Comparison with Predictive Assays

Energy Technology Data Exchange (ETDEWEB)

Chvetsov, A; Schwartz, J; Mayr, N [University of Washington, Seattle, WA (United States); Yartsev, S [London Health Sciences Centre, London, Ontario (Canada)

2014-06-01

Purpose: To show that a distribution of cell surviving fractions S{sub 2} in a heterogeneous group of patients can be derived from tumor-volume variation curves during radiotherapy for non-small cell lung cancer. Methods: Our analysis was based on two data sets of tumor-volume variation curves for heterogeneous groups of 17 patients treated for nonsmall cell lung cancer with conventional dose fractionation. The data sets were obtained previously at two independent institutions by using megavoltage (MV) computed tomography (CT). Statistical distributions of cell surviving fractions S{sup 2} and cell clearance half-lives of lethally damaged cells T1/2 have been reconstructed in each patient group by using a version of the two-level cell population tumor response model and a simulated annealing algorithm. The reconstructed statistical distributions of the cell surviving fractions have been compared to the distributions measured using predictive assays in vitro. Results: Non-small cell lung cancer presents certain difficulties for modeling surviving fractions using tumor-volume variation curves because of relatively large fractional hypoxic volume, low gradient of tumor-volume response, and possible uncertainties due to breathing motion. Despite these difficulties, cell surviving fractions S{sub 2} for non-small cell lung cancer derived from tumor-volume variation measured at different institutions have similar probability density functions (PDFs) with mean values of 0.30 and 0.43 and standard deviations of 0.13 and 0.18, respectively. The PDFs for cell surviving fractions S{sup 2} reconstructed from tumor volume variation agree with the PDF measured in vitro. Comparison of the reconstructed cell surviving fractions with patient survival data shows that the patient survival time decreases as the cell surviving fraction increases. Conclusion: The data obtained in this work suggests that the cell surviving fractions S{sub 2} can be reconstructed from the tumor volume

SU-E-T-427: Cell Surviving Fractions Derived From Tumor-Volume Variation During Radiotherapy for Non-Small Cell Lung Cancer: Comparison with Predictive Assays

International Nuclear Information System (INIS)

Chvetsov, A; Schwartz, J; Mayr, N; Yartsev, S

2014-01-01

Purpose: To show that a distribution of cell surviving fractions S 2 in a heterogeneous group of patients can be derived from tumor-volume variation curves during radiotherapy for non-small cell lung cancer. Methods: Our analysis was based on two data sets of tumor-volume variation curves for heterogeneous groups of 17 patients treated for nonsmall cell lung cancer with conventional dose fractionation. The data sets were obtained previously at two independent institutions by using megavoltage (MV) computed tomography (CT). Statistical distributions of cell surviving fractions S 2 and cell clearance half-lives of lethally damaged cells T1/2 have been reconstructed in each patient group by using a version of the two-level cell population tumor response model and a simulated annealing algorithm. The reconstructed statistical distributions of the cell surviving fractions have been compared to the distributions measured using predictive assays in vitro. Results: Non-small cell lung cancer presents certain difficulties for modeling surviving fractions using tumor-volume variation curves because of relatively large fractional hypoxic volume, low gradient of tumor-volume response, and possible uncertainties due to breathing motion. Despite these difficulties, cell surviving fractions S 2 for non-small cell lung cancer derived from tumor-volume variation measured at different institutions have similar probability density functions (PDFs) with mean values of 0.30 and 0.43 and standard deviations of 0.13 and 0.18, respectively. The PDFs for cell surviving fractions S 2 reconstructed from tumor volume variation agree with the PDF measured in vitro. Comparison of the reconstructed cell surviving fractions with patient survival data shows that the patient survival time decreases as the cell surviving fraction increases. Conclusion: The data obtained in this work suggests that the cell surviving fractions S 2 can be reconstructed from the tumor volume variation curves measured

A sensitive competitive binding assay for exogenous and endogenous heparins

International Nuclear Information System (INIS)

Dawes, J.; Pepper, D.S.

1982-01-01

A new type of assay for heparins has been devised, in which the test material competes with 125 I-labelled heparin for binding to protamine-Sepharose. The assay is very sensitive and will measure heparin concentrations down to 10 ng ml-1. It responds to both the degree of sulphation and the molecular weight of acidic polysaccharides, but is independent of their biological activities. It can be used to quantitate heparins in biological fluids after pretreatment of the samples with protease. In this way endogenous heparins were measured in normal human serum, plasma and urine. The assay is extremely versatile and has great potential for the investigation of endogenous and exogenous heparins

Rapid assay of intrinsic radiosensitivity based on apoptosis in human CD4 and CD8 T-lymphocytes

International Nuclear Information System (INIS)

Ozsahin, Mahmut; Ozsahin, Huelya; Yuquan, Shi; Larsson, Boerje; Wuergler, Friedrich E.; Crompton, Nigel E. A.

1997-01-01

Purpose: An assay for radiosensitivity has numerous applications in the clinic. Avoidance of acute responses, prediction of normal tissue toxicity, and individualization of patient radiotherapy are included among these. We have developed a rapid assay (about 24 h) able to predict intrinsic radiosensitivity of CD4 and CD8 T-lymphocytes based on radiation-induced apoptosis. Methods and Materials: Fresh blood samples (1-2 ml in heparinized tubes) were irradiated with 0-, 2-, and 8-Gy X rays at a dose rate of approximately 3 Gy/min. Following irradiation, the cells were collected and prepared for flow-cytometric analysis and cell sorting. In conjunction with the CellQuest software available with the FACSVantage cell sorter (Becton-Dickinson), two T-lymphocyte types were analyzed on the basis of their cell-specific antigens (CD4 and CD8), and DNA was stained with DAPI. Following the separation of these cell types, radiation-induced cell death was assessed. Cytotoxicity was characterized by gradual degradation of internucleosomal DNA which results in a sub-G1 peak on the DNA histogram, and by the associated loss of surface antigens causing an intermediate positive peak in the antibody histogram. Using the assay, we investigated the interdonor variation in a cohort of 45 healthy adult blood donors and 5 children [one had immunodeficiency, centromeric instability, and facial anomalies syndrome (ICF), and one had ataxia telangiectasia (AT)]. Intradonor variation was assessed with 10 different experiments from a single donor. Results: CD4 and CD8 T-lymphocyte radiosensitivities were correlated (r 0.63 and 0.65 for 2 and 8 Gy, respectively) in 45 adult donors. Both for CD4 and CD8 cells, 2 and 8 Gy irradiation responses showed a good correlation (r 0.77 for both). Interdonor variation was significantly higher than intradonor variation (p < 0.0005) for all CD4 and CD8 data. We observed a decrease in the antigen fluorescence of dying cells, a phenomenon referred to as antigen

Comparative analysis of face recognition techniques with illumination variation

International Nuclear Information System (INIS)

Jondhale, K C; Waghmare, L M

2010-01-01

Illumination variation is one of the major challenges in the face recognition. To deal with this problem, this paper presents comparative analysis of three different techniques. First, the DCT is employed to compensate for illumination variations in the logarithm domain. Since illumination variation lies mainly in the low frequency band, an appropriate number of DCT coefficients are truncated to reduce the variations under different lighting conditions. The nearest neighbor classifier based on Euclidean distance is employed for classification. Second, the performance of PCA is checked on normalized image. PCA is a technique used to reduce multidimensional data sets to a lower dimension for analysis. Third, LDA based methods gives a satisfactory result under controlled lighting condition. But its performance under large illumination variation is not satisfactory. So, the performance of LDA is checked on normalized image. Experimental results on the Yale B and ORL database show that the proposed approach of application of PCA and LDA on normalized dataset improves the performance significantly for the face images with large illumination variations.

Effects of estradiol and progesterone on the variability of the micronucleus assay

International Nuclear Information System (INIS)

Baeyens, Ans; Vandersickel, Veerle; Thierens, Hubert; Ridder, Leo De; Vral, Anne

2005-01-01

To investigate chromosomal radiosensitivity of lymphocytes the micronucleus (MN) assay has been used for many years. The results of these studies suggest the use of the MN assay as a biomarker for cancer predisposition. However, the MN assay has still some limitations associated with the reproducibility and sensitivity. Especially a high intra-individual variability has been observed. An explanation for this high intra-individual variability is not yet available. In literature it is suggested that the high variability among females is attributable to hormonal status. In this study we investigated if the high intra-individual variability in micronucleus formation in lymphocytes of females after in vitro exposure to ionising radiation is caused by variations in hormone levels of estradiol (E2) and progesterone (PROG). For this, the MN assay was performed on blood samples of 18 healthy women during 7 consecutive weeks while the estradiol and progesterone levels were determined at the same time. The MN assay was also examined in cultures of isolated blood lymphocytes with estradiol or progesterone levels added in vitro. The results demonstrated that estradiol and progesterone levels have no influence on the variations in radiation-induced MN yields observed in blood samples of healthy women. These conclusions were confirmed by the 'in vitro' experiments as no correlation between the MN yields and the concentrations of hormones (estradiol or progesterone) added in vitro to isolated lymphocytes cultures was observed

A national quality control scheme for serum HGH assays

International Nuclear Information System (INIS)

Hunter, W.M.; McKenzie, I.

1979-01-01

In the autumn of 1975 the Supraregional Assay Service established a Quality Control Sub-Committee and the intra-laboratory QC Scheme for Growth Hormone (HGH) assays which is described here has served, in many respects, as a pilot scheme for protein RIA. Major improvements in accuracy, precision and between-laboratory agreement can be brought about by intensively interactive quality control schemes. A common standard is essential and should consist of ampoules used for one or only a small number of assays. Accuracy and agreement were not good enough to allow the overall means to serve as target values but a group of 11 laboratories were sufficiently accurate to provide a 'reference group mean' to so serve. Gross non-specificity was related to poor assay design and was quickly eliminated. Within-laboratory between-batch variability was much worse than that normally claimed for simple protein hormone RIA. A full report on this Scheme will appear shortly in Annals of Clinical Biochemistry. (Auth.)

Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations

Directory of Open Access Journals (Sweden)

Carlos Fernando de Mello Júnior

2016-06-01

Full Text Available Abstract Conventional angiography is still considered the gold standard for the study of the anatomy and of vascular diseases of the abdomen. However, the advent of multidetector computed tomography and techniques of digital image reconstruction has provided an alternative means of performing angiography, without the risks inherent to invasive angiographic examinations. Therefore, within the field of radiology, there is an ever-increasing demand for deeper knowledge of the anatomy of the regional vasculature and its variations. Variations in the renal vascular system are relatively prevalent in the venous and arterial vessels. For various conditions in which surgical planning is crucial to the success of the procedure, knowledge of this topic is important. The aim of this study was to familiarize the general radiologist with variations in the renal vascular system. To that end, we prepared a pictorial essay comprising multidetector computed tomography images obtained in a series of cases. We show patterns representative of the most common anatomical variations in the arterial blood supply to the kidneys, calling attention to the nomenclature, as well as to the clinical and surgical implications of such variations.

Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations

International Nuclear Information System (INIS)

Mello Junior, Carlos Fernando de; Araujo Neto, Severino Aires; Carvalho Junior, Arlindo Monteiro de; Negromonte, Gustavo Ramalho Pessoa; Oliveira, Carollyne Dantas de; Reboucas, Rafael Batista

2016-01-01

Conventional angiography is still considered the gold standard for the study of the anatomy and of vascular diseases of the abdomen. However, the advent of multidetector computed tomography and techniques of digital image reconstruction has provided an alternative means of performing angiography, without the risks inherent to invasive angiographic examinations. Therefore, within the field of radiology, there is an ever-increasing demand for deeper knowledge of the anatomy of the regional vasculature and its variations. Variations in the renal vascular system are relatively prevalent in the venous and arterial vessels. For various conditions in which surgical planning is crucial to the success of the procedure, knowledge of this topic is important. The aim of this study was to familiarize the general radiologist with variations in the renal vascular system. To that end, we prepared a pictorial essay comprising multidetector computed tomography images obtained in a series of cases. We show patterns representative of the most common anatomical variations in the arterial blood supply to the kidneys, calling attention to the nomenclature, as well as to the clinical and surgical implications of such variations. (author)

Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations

Energy Technology Data Exchange (ETDEWEB)

Mello Junior, Carlos Fernando de; Araujo Neto, Severino Aires; Carvalho Junior, Arlindo Monteiro de; Negromonte, Gustavo Ramalho Pessoa; Oliveira, Carollyne Dantas de [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Reboucas, Rafael Batista, E-mail: severinoaires@hotmail.com [Faculdade de Ciencias Medicas da Paraiba, Joao Pessoa, PB (Brazil)

2016-05-15

Conventional angiography is still considered the gold standard for the study of the anatomy and of vascular diseases of the abdomen. However, the advent of multidetector computed tomography and techniques of digital image reconstruction has provided an alternative means of performing angiography, without the risks inherent to invasive angiographic examinations. Therefore, within the field of radiology, there is an ever-increasing demand for deeper knowledge of the anatomy of the regional vasculature and its variations. Variations in the renal vascular system are relatively prevalent in the venous and arterial vessels. For various conditions in which surgical planning is crucial to the success of the procedure, knowledge of this topic is important. The aim of this study was to familiarize the general radiologist with variations in the renal vascular system. To that end, we prepared a pictorial essay comprising multidetector computed tomography images obtained in a series of cases. We show patterns representative of the most common anatomical variations in the arterial blood supply to the kidneys, calling attention to the nomenclature, as well as to the clinical and surgical implications of such variations. (author)

An individual urinary proteome analysis in normal human beings to define the minimal sample number to represent the normal urinary proteome

Directory of Open Access Journals (Sweden)

Liu Xuejiao

2012-11-01

Full Text Available Abstract Background The urinary proteome has been widely used for biomarker discovery. A urinary proteome database from normal humans can provide a background for discovery proteomics and candidate proteins/peptides for targeted proteomics. Therefore, it is necessary to define the minimum number of individuals required for sampling to represent the normal urinary proteome. Methods In this study, inter-individual and inter-gender variations of urinary proteome were taken into consideration to achieve a representative database. An individual analysis was performed on overnight urine samples from 20 normal volunteers (10 males and 10 females by 1DLC/MS/MS. To obtain a representative result of each sample, a replicate 1DLCMS/MS analysis was performed. The minimal sample number was estimated by statistical analysis. Results For qualitative analysis, less than 5% of new proteins/peptides were identified in a male/female normal group by adding a new sample when the sample number exceeded nine. In addition, in a normal group, the percentage of newly identified proteins/peptides was less than 5% upon adding a new sample when the sample number reached 10. Furthermore, a statistical analysis indicated that urinary proteomes from normal males and females showed different patterns. For quantitative analysis, the variation of protein abundance was defined by spectrum count and western blotting methods. And then the minimal sample number for quantitative proteomic analysis was identified. Conclusions For qualitative analysis, when considering the inter-individual and inter-gender variations, the minimum sample number is 10 and requires a balanced number of males and females in order to obtain a representative normal human urinary proteome. For quantitative analysis, the minimal sample number is much greater than that for qualitative analysis and depends on the experimental methods used for quantification.

Qualification of standard membrane-feeding assay with Plasmodium falciparum malaria and potential improvements for future assays.

Directory of Open Access Journals (Sweden)

Kazutoyo Miura

Full Text Available Vaccines that interrupt malaria transmission are of increasing interest and a robust functional assay to measure this activity would promote their development by providing a biologically relevant means of evaluating potential vaccine candidates. Therefore, we aimed to qualify the standard membrane-feeding assay (SMFA. The assay measures the transmission-blocking activity of antibodies by feeding cultured P. falciparum gametocytes to Anopheles mosquitoes in the presence of the test antibodies and measuring subsequent mosquito infection. The International Conference on Harmonisation (ICH Harmonised Tripartite Guideline Q2(R1 details characteristics considered in assay validation. Of these characteristics, we decided to qualify the SMFA for Precision, Linearity, Range and Specificity. The transmission-blocking 4B7 monoclonal antibody was tested over 6 feeding experiments at several concentrations to determine four suitable concentrations that were tested in triplicate in the qualification experiments (3 additional feeds to evaluate Precision, Linearity and Range. For Specificity, 4B7 was tested in the presence of normal mouse IgG. We determined intra- and inter-assay variability of % inhibition of mean oocyst intensity at each concentration of 4B7 (lower concentrations showed higher variability. We also showed that % inhibition was dependent on 4B7 concentration and the activity is specific to 4B7. Since obtaining empirical data is time-consuming, we generated a model using data from all 9 feeds and simulated the effects of different parameters on final readouts to improve the assay procedure and analytical methods for future studies. For example, we estimated the effect of number of mosquitoes dissected on variability of % inhibition, and simulated the relationship between % inhibition in oocyst intensity and % inhibition of prevalence of infected mosquitos at different mean oocysts in the control. SMFA is one of the few biological assays used in

Generating log-normally distributed random numbers by using the Ziggurat algorithm

International Nuclear Information System (INIS)

Choi, Jong Soo

2016-01-01

Uncertainty analyses are usually based on the Monte Carlo method. Using an efficient random number generator(RNG) is a key element in success of Monte Carlo simulations. Log-normal distributed variates are very typical in NPP PSAs. This paper proposes an approach to generate log normally distributed variates based on the Ziggurat algorithm and evaluates the efficiency of the proposed Ziggurat RNG. The proposed RNG can be helpful to improve the uncertainty analysis of NPP PSAs. This paper focuses on evaluating the efficiency of the Ziggurat algorithm from a NPP PSA point of view. From this study, we can draw the following conclusions. - The Ziggurat algorithm is one of perfect random number generators to product normal distributed variates. - The Ziggurat algorithm is computationally much faster than the most commonly used method, Marsaglia polar method

Flow cytometric immunobead assay for quantitative detection of platelet autoantibodies in immune thrombocytopenia patients.

Science.gov (United States)

Zhai, Juping; Ding, Mengyuan; Yang, Tianjie; Zuo, Bin; Weng, Zhen; Zhao, Yunxiao; He, Jun; Wu, Qingyu; Ruan, Changgeng; He, Yang

2017-10-23

Platelet autoantibody detection is critical for immune thrombocytopenia (ITP) diagnosis and prognosis. Therefore, we aimed to establish a quantitative flow cytometric immunobead assay (FCIA) for ITP platelet autoantibodies evaluation. Capture microbeads coupled with anti-GPIX, -GPIb, -GPIIb, -GPIIIa and P-selectin antibodies were used to bind the platelet-bound autoantibodies complex generated from plasma samples of 250 ITP patients, 163 non-ITP patients and 243 healthy controls, a fluorescein isothiocyanate (FITC)-conjugated secondary antibody was the detector reagent and mean fluorescence intensity (MFI) signals were recorded by flow cytometry. Intra- and inter-assay variations of the quantitative FCIA assay were assessed. Comparisons of the specificity, sensitivity and accuracy between quantitative and qualitative FCIA or monoclonal antibody immobilization of platelet antigen (MAIPA) assay were performed. Finally, treatment process was monitored by our quantitative FCIA in 8 newly diagnosed ITPs. The coefficient of variations (CV) of the quantitative FCIA assay were respectively 9.4, 3.8, 5.4, 5.1 and 5.8% for anti-GPIX, -GPIb, -GPIIIa, -GPIIb and -P-selectin autoantibodies. Elevated levels of autoantibodies against platelet glycoproteins GPIX, GPIb, GPIIIa, GPIIb and P-selectin were detected by our quantitative FCIA in ITP patients compared to non-ITP patients or healthy controls. The sensitivity, specificity and accuracy of our quantitative assay were respectively 73.13, 81.98 and 78.65% when combining all 5 autoantibodies, while the sensitivity, specificity and accuracy of MAIPA assay were respectively 41.46, 90.41 and 72.81%. A quantitative FCIA assay was established. Reduced levels of platelet autoantibodies could be confirmed by our quantitative FCIA in ITP patients after corticosteroid treatment. Our quantitative assay is not only good for ITP diagnosis but also for ITP treatment monitoring.

Defecography: A study of normal volunteers

International Nuclear Information System (INIS)

Shorvon, P.; Stevenson, G.W.; McHugh, S.; Somers, P.

1987-01-01

This study of young volunteers was set up in an effort to establish true normal measurements for defecography with minimum selection bias. The results describe the mean (and the range) for the following: anorectal angle; anorectal junction position at rest; excursion on lift, strain, and evacuation; anal canal length and degree of closure; and the frequency and degree of features such as rectocele and intussusception which have previously been called abnormalities. The results indicate that there is a very wide range of normal appearances. Knowledge of these normal variations is important to avoid overreporting and unnecessary surgery

Normalized difference vegetation index (NDVI) variation among cultivars and environments

Science.gov (United States)

Although Nitrogen (N) is an essential nutrient for crop production, large preplant applications of fertilizer N can result in off-field loss that causes environmental concerns. Canopy reflectance is being investigated for use in variable rate (VR) N management. Normalized difference vegetation index...

Environmental variation partitioned into separate heritable components

DEFF Research Database (Denmark)

Ørsted, Michael; Rohde, Palle Duun; Hoffmann, Ary A

2018-01-01

Trait variation is normally separated into genetic and environmental components, yet genetic factors also control the expression of environmental variation, encompassing plasticity across environmental gradients and within-environment responses. We defined four components of environmental variation......: plasticity across environments, variability in plasticity, variation within environments, and differences in within-environment variation across environments. We assessed these components for cold tolerance across five rearing temperatures using the Drosophila melanogaster Genetic Reference Panel (DGRP...

Best-Matched Internal Standard Normalization in Liquid Chromatography-Mass Spectrometry Metabolomics Applied to Environmental Samples.

Science.gov (United States)

Boysen, Angela K; Heal, Katherine R; Carlson, Laura T; Ingalls, Anitra E

2018-01-16

The goal of metabolomics is to measure the entire range of small organic molecules in biological samples. In liquid chromatography-mass spectrometry-based metabolomics, formidable analytical challenges remain in removing the nonbiological factors that affect chromatographic peak areas. These factors include sample matrix-induced ion suppression, chromatographic quality, and analytical drift. The combination of these factors is referred to as obscuring variation. Some metabolomics samples can exhibit intense obscuring variation due to matrix-induced ion suppression, rendering large amounts of data unreliable and difficult to interpret. Existing normalization techniques have limited applicability to these sample types. Here we present a data normalization method to minimize the effects of obscuring variation. We normalize peak areas using a batch-specific normalization process, which matches measured metabolites with isotope-labeled internal standards that behave similarly during the analysis. This method, called best-matched internal standard (B-MIS) normalization, can be applied to targeted or untargeted metabolomics data sets and yields relative concentrations. We evaluate and demonstrate the utility of B-MIS normalization using marine environmental samples and laboratory grown cultures of phytoplankton. In untargeted analyses, B-MIS normalization allowed for inclusion of mass features in downstream analyses that would have been considered unreliable without normalization due to obscuring variation. B-MIS normalization for targeted or untargeted metabolomics is freely available at https://github.com/IngallsLabUW/B-MIS-normalization .

An Integrated Approach for RNA-seq Data Normalization.

Science.gov (United States)

Yang, Shengping; Mercante, Donald E; Zhang, Kun; Fang, Zhide

2016-01-01

DNA copy number alteration is common in many cancers. Studies have shown that insertion or deletion of DNA sequences can directly alter gene expression, and significant correlation exists between DNA copy number and gene expression. Data normalization is a critical step in the analysis of gene expression generated by RNA-seq technology. Successful normalization reduces/removes unwanted nonbiological variations in the data, while keeping meaningful information intact. However, as far as we know, no attempt has been made to adjust for the variation due to DNA copy number changes in RNA-seq data normalization. In this article, we propose an integrated approach for RNA-seq data normalization. Comparisons show that the proposed normalization can improve power for downstream differentially expressed gene detection and generate more biologically meaningful results in gene profiling. In addition, our findings show that due to the effects of copy number changes, some housekeeping genes are not always suitable internal controls for studying gene expression. Using information from DNA copy number, integrated approach is successful in reducing noises due to both biological and nonbiological causes in RNA-seq data, thus increasing the accuracy of gene profiling.

Normalization of satellite imagery

Science.gov (United States)

Kim, Hongsuk H.; Elman, Gregory C.

1990-01-01

Sets of Thematic Mapper (TM) imagery taken over the Washington, DC metropolitan area during the months of November, March and May were converted into a form of ground reflectance imagery. This conversion was accomplished by adjusting the incident sunlight and view angles and by applying a pixel-by-pixel correction for atmospheric effects. Seasonal color changes of the area can be better observed when such normalization is applied to space imagery taken in time series. In normalized imagery, the grey scale depicts variations in surface reflectance and tonal signature of multi-band color imagery can be directly interpreted for quantitative information of the target.

A Complete Color Normalization Approach to Histopathology Images Using Color Cues Computed From Saturation-Weighted Statistics.

Science.gov (United States)

Li, Xingyu; Plataniotis, Konstantinos N

2015-07-01

In digital histopathology, tasks of segmentation and disease diagnosis are achieved by quantitative analysis of image content. However, color variation in image samples makes it challenging to produce reliable results. This paper introduces a complete normalization scheme to address the problem of color variation in histopathology images jointly caused by inconsistent biopsy staining and nonstandard imaging condition. Method : Different from existing normalization methods that either address partial cause of color variation or lump them together, our method identifies causes of color variation based on a microscopic imaging model and addresses inconsistency in biopsy imaging and staining by an illuminant normalization module and a spectral normalization module, respectively. In evaluation, we use two public datasets that are representative of histopathology images commonly received in clinics to examine the proposed method from the aspects of robustness to system settings, performance consistency against achromatic pixels, and normalization effectiveness in terms of histological information preservation. As the saturation-weighted statistics proposed in this study generates stable and reliable color cues for stain normalization, our scheme is robust to system parameters and insensitive to image content and achromatic colors. Extensive experimentation suggests that our approach outperforms state-of-the-art normalization methods as the proposed method is the only approach that succeeds to preserve histological information after normalization. The proposed color normalization solution would be useful to mitigate effects of color variation in pathology images on subsequent quantitative analysis.

Performance evaluation of new automated hepatitis B viral markers in the clinical laboratory: two quantitative hepatitis B surface antigen assays and an HBV core-related antigen assay.

Science.gov (United States)

Park, Yongjung; Hong, Duck Jin; Shin, Saeam; Cho, Yonggeun; Kim, Hyon-Suk

2012-05-01

We evaluated quantitative hepatitis B surface antigen (qHBsAg) assays and a hepatitis B virus (HBV) core-related antigen (HBcrAg) assay. A total of 529 serum samples from patients with hepatitis B were tested. HBsAg levels were determined by using the Elecsys (Roche Diagnostics, Indianapolis, IN) and Architect (Abbott Laboratories, Abbott Park, IL) qHBsAg assays. HBcrAg was measured by using Lumipulse HBcrAg assay (Fujirebio, Tokyo, Japan). Serum aminotransferases and HBV DNA were respectively quantified by using the Hitachi 7600 analyzer (Hitachi High-Technologies, Tokyo, Japan) and the Cobas AmpliPrep/Cobas TaqMan test (Roche). Precision of the qHBsAg and HBcrAg assays was assessed, and linearity of the qHBsAg assays was verified. All assays showed good precision performance with coefficients of variation between 4.5% and 5.3% except for some levels. Both qHBsAg assays showed linearity from 0.1 to 12,000.0 IU/mL and correlated well (r = 0.9934). HBsAg levels correlated with HBV DNA (r = 0.3373) and with HBcrAg (r = 0.5164), and HBcrAg also correlated with HBV DNA (r = 0.5198; P < .0001). This observation could provide impetus for further research to elucidate the clinical usefulness of the qHBsAg and HBcrAg assays.

Biological variation in tPA-induced plasma clot lysis time.

Science.gov (United States)

Talens, Simone; Malfliet, Joyce J M C; Rudež, Goran; Spronk, Henri M H; Janssen, Nicole A H; Meijer, Piet; Kluft, Cornelis; de Maat, Moniek P M; Rijken, Dingeman C

2012-10-01

Hypofibrinolysis is a risk factor for venous and arterial thrombosis, and can be assessed by using a turbidimetric tPA-induced clot lysis time (CLT) assay. Biological variation in clot lysis time may affect the interpretation and usefulness of CLT as a risk factor for thrombosis. Sufficient information about assay variation and biological variation in CLT is not yet available. Thus, this study aimed to determine the analytical, within-subject and between-subject variation in CLT. We collected blood samples from 40 healthy individuals throughout a period of one year (average 11.8 visits) and determined the CLT of each plasma sample in duplicate. The mean (± SD) CLT was 83.8 (± 11.1) minutes. The coefficients of variation for total variation, analytical variation, within-subject variation and between-subject variation were 13.4%, 2.6%, 8.2% and 10.2%, respectively. One measurement can estimate the CLT that does not deviate more than 20% from its true value. The contribution of analytical variation to the within-subject variation was 5.0%, the index of individuality was 0.84 and the reference change value was 23.8%. The CLT was longer in the morning compared to the afternoon and was slightly longer in older individuals (> 40 years) compared to younger (≤40 years) individuals. There was no seasonal variation in CLT and no association with air pollution. CLT correlated weakly with fibrinogen, C-reactive protein, prothrombin time and thrombin generation. This study provides insight into the biological variation of CLT, which can be used in future studies testing CLT as a potential risk factor for thrombosis.

Value of scintimetry compared with histomorphology, parathormone assay, densitometry and radiology in renal osteopathy

Energy Technology Data Exchange (ETDEWEB)

Lingg, G.; Nebel, G.; Dorr, S.

1982-01-01

The value of scintimetry is compared with histomorphology, parathormone assay, densitometry and radiology in renal osteopathy. The distribution of sup(99m)Tc-Sn-MDP in the thigh was estimated according to two different indices in 60 normal patients, 21 patients undergoing haemodialysis and one who had had a renal transplant. Deviation of the indices in these patients from the normal are significant. The indices were correlated with respect to their accuracy in detecting renal osteopathy with histomorphometry (as the reference method), radiological diagnosis, densitometry, parathormone assay and other laboratory tests. Accuracy of the method is high and, like histomorphometry, is over 9O%.

Assay of fluconazole by high-performance liquid chromatography with a mixed-phase column.

OpenAIRE

Wallace, J E; Harris, S C; Gallegos, J; Foulds, G; Chen, T J; Rinaldi, M G

1992-01-01

A mixed-phase liquid chromatographic column was used to assay fluconazole in plasma, serum, and cerebrospinal fluid. The assay was linear from 0.2 to 20 micrograms/ml, with an average coefficient of variation of less than 5%. The partitioning of the drug between serum and cerebrospinal fluid was determined for 34 patients. The method was demonstrated to be suitable for both pharmacokinetic studies and monitoring of patients receiving treatment with this antifungal agent.

Identification of high-affinity anti-IL-1 α autoantibodies in normal human serum as an interfering substance in a sensitive enzyme-linked immunosorbent assay for IL-1 α

International Nuclear Information System (INIS)

Mae, N.; Liberato, D.J.; Chizzonite, R.; Satoh, H.

1991-01-01

A highly reproducible, sensitive, and specific sandwich enzyme-linked immunosorbent assay (ELISA) for recombinant human IL-1 α (rhIL-1 alpha) has been developed. Results from this ELISA have demonstrated that the concentration of rhIL-1 α added to normal human serum (NHS) decreased by 16.3% after 3 h and 24.9% after 6 h at room temperature. Molecular exclusion column chromatography with Sephacryl S-300 HR revealed that 125I-labeled IL-1 α added to normal human serum rapidly formed higher molecular weight complexes without indication of proteolytic degradation. The observed reduction in immunoreactivity was correlated with this protein complex formation and accounted for the apparent instability of rhIL-1 α in NHS. Immunoblot analysis indicated that the molecular weight of the binding protein was 150-160K, and the IL-1 α binding activity was removed and recovered from NHS by Protein-G affinity chromatography; indicating that the binding protein was IL-1 α-specific IgG. The binding of 125I-labeled IL-1 α to the serum binding proteins could be inhibited by unlabeled IL-1 alpha (IC50 = 7.4 x 10(-11) M) but not by unlabeled IL-1 β. Kinetic analysis with 125I-labeled IL-1 alpha revealed that the average binding affinity of these IL-1 α-specific IgGs was 4.7 x 10(10) M-1. These results suggest that these autoantibodies may interfere with the detection of IL-1 α in human serum by various assay systems and also could be a regulator of circulating IL-1 α

Sensitivity to radiation of human normal, hyperthyroid, and neoplastic thyroid epithelial cells in primary culture

International Nuclear Information System (INIS)

Miller, R.C.; Hiraoka, Toshio; Kopecky, K.J.; Nakamura, Nori; Jones, M.P.; Ito, Toshio; Clifton, K.H.

1986-09-01

Samples of thyroid tissue removed surgically from 63 patients were cultured in vitro and X-irradiated to investigate the radiosensitivities of various types of thyroid epithelial cells. A total of 76 samples were obtained, including neoplastic cells from patients with papillary carcinoma (PC) or follicular adenoma (FA), cells from hyperthyroidism (HY) patients, and normal cells from the surgical margins of PC and FA patients. Culturing of the cells was performed in a manner which has been shown to yield a predominance of epithelial cells. Results of colony formation assays indicated that cells from HY and FA patients were the least radiosensitive: when adjusted to the overall geometric mean plating efficiency of 5.5 %, the average mean lethal dose D 0 was 97.6 cGy for HY cells, and 96.7 cGy and 94.3 cGy, respectively, for neoplastic and normal cells from FA patients. Cells from PC patients were more radiosensitive, normal cells having an adjusted average D 0 of 85.0 cGy and PC cells a significantly (p = .001) lower average D 0 of 74.4 cGy. After allowing for this variation by cell type, in vitro radiosensitivity was not significantly related to age at surgery (p = .82) or sex (p = .10). These results suggest that malignant thyroid cells may be especially radiosensitive. (author)

Correction of Bowtie-Filter Normalization and Crescent Artifacts for a Clinical CBCT System.

Science.gov (United States)

Zhang, Hong; Kong, Vic; Huang, Ke; Jin, Jian-Yue

2017-02-01

To present our experiences in understanding and minimizing bowtie-filter crescent artifacts and bowtie-filter normalization artifacts in a clinical cone beam computed tomography system. Bowtie-filter position and profile variations during gantry rotation were studied. Two previously proposed strategies (A and B) were applied to the clinical cone beam computed tomography system to correct bowtie-filter crescent artifacts. Physical calibration and analytical approaches were used to minimize the norm phantom misalignment and to correct for bowtie-filter normalization artifacts. A combined procedure to reduce bowtie-filter crescent artifacts and bowtie-filter normalization artifacts was proposed and tested on a norm phantom, CatPhan, and a patient and evaluated using standard deviation of Hounsfield unit along a sampling line. The bowtie-filter exhibited not only a translational shift but also an amplitude variation in its projection profile during gantry rotation. Strategy B was better than strategy A slightly in minimizing bowtie-filter crescent artifacts, possibly because it corrected the amplitude variation, suggesting that the amplitude variation plays a role in bowtie-filter crescent artifacts. The physical calibration largely reduced the misalignment-induced bowtie-filter normalization artifacts, and the analytical approach further reduced bowtie-filter normalization artifacts. The combined procedure minimized both bowtie-filter crescent artifacts and bowtie-filter normalization artifacts, with Hounsfield unit standard deviation being 63.2, 45.0, 35.0, and 18.8 Hounsfield unit for the best correction approaches of none, bowtie-filter crescent artifacts, bowtie-filter normalization artifacts, and bowtie-filter normalization artifacts + bowtie-filter crescent artifacts, respectively. The combined procedure also demonstrated reduction of bowtie-filter crescent artifacts and bowtie-filter normalization artifacts in a CatPhan and a patient. We have developed a step

Colony variation of Helicobacter pylori: pathogenic potential is correlated to cell wall lipid composition.

Science.gov (United States)

Bukholm, G; Tannaes, T; Nedenskov, P; Esbensen, Y; Grav, H J; Hovig, T; Ariansen, S; Guldvog, I

1997-05-01

Differences in expression of disease after infection with Helicobacter pylori have so far been connected with host factors and bacterial interstrain variation. In this study, spontaneous and ecology-mediated intrastrain variation was examined. Four clinical isolates of H. pylori were shown to give rise to two colony forms. Bacterial morphology was examined by electron microscopy. Bacterial fractions were examined for proteins using ion exchange chromatography and SDS-PAGE; for lipids using thin-layer chromatography, lipid anion-exchange chromatography, column chromatography on silica gel, 31P-NMR, gas chromatography and mass spectrometry. Bacterial in vitro invasiveness and adhesiveness were examined in two different systems, and urease and VacA toxin were assayed by Western blot analysis. H. pylori was shown to give rise to two colony forms: at normal pH the population was dominated by L colonies. One strain was chosen for further studies. Bacteria from L colonies retained VacA toxin and urease, did not invade or adhere to epithelial cells, and contained normal quantities of phosphatidylethanolamine. In a small frequency, spontaneous S colonies were formed. Bacteria from these colonies released VacA and urease, adhered to and invaded epithelial cells and contained increased amounts of lysophosphatidyl ethanolamine and phosphatidyl serine. After addition of HCl to the culture medium (pH6), almost only S colonies were formed. The results demonstrate that environmental factors, such as HCl, can change the bacterial cell wall, and thereby enhance expression of virulence factors of H. pylori in vitro. A similar in vivo variation would have implications for our understanding of the interaction between HCl secretion in the gastric mucosa and H. pylori in the development of peptic ulcer disease.

Assays for mammalian tyrosinase: a comparative study

International Nuclear Information System (INIS)

Jara, J.R.; Solano, F.; Lozano, J.A.

1988-01-01

This work describes a comparative study of the tyrosinase activity determined using three methods which are the most extensively employed; two radiometric assays using L-tyrosine as substrate (tyrosine hydroxylase and melanin formation activities) and one spectrophotometric assay using L-dopa (dopa oxidase activity). The three methods were simultaneously employed to measure the activities of the soluble, melanosomal, and microsomal tyrosinase isozymes from Harding-Passey mouse melanoma through their purification processes. The aim of this study was to find any correlation among the tyrosinase activities measured by the three different assays and to determine whether that correlation varied with the isozyme and its degree of purification. The results show that mammalian tyrosinase has a greater turnover number for L-dopa than for L-tyrosine. Thus, enzyme activity, expressed as mumol of substrate transformed per min, is higher in assays using L-dopa as substrate than those using L-tyrosine. Moreover, the percentage of hydroxylated L-tyrosine that is converted into melanin is low and is affected by several factors, apparently decreasing the tyrosinase activity measured by the melanin formation assay. Bearing these considerations in mind, average interassay factors are proposed. Their values are 10 to transform melanin formation into tyrosine hydroxylase activity, 100 to transform tyrosine hydroxylase into dopa oxidase activity, and 1,000 to transform melanin formation into dopa oxidase activity. Variations in these values due to the presence in the tyrosinase preparations of either inhibitors or regulatory factors in melanogenesis independent of tyrosinase are also discussed

Development of a human somatic mutation detection method--GPA assay

International Nuclear Information System (INIS)

Mao Jianping; Dong Yan; Liu Bin; Lin Ruxian; Sun Zhixian

2000-01-01

Objective: To study the damage to human body caused by environmental radiation, and supervise the somatic mutations. Methods: Three monoclonal antibodies specific to M-type(3G4), N-type(6A8), and MN-type (3C5) of glycophorin A, respectively, were prepared. Fluorescence or biotin conjugated antibodies were bound specifically to formalin and/or dimethyl suber-imidate fixed erythrocytes. M, MN and N type cells were divided by cytometry to demonstrate the erythrocyte mutation characteristics (MN→MO, MM, NO, NN) and give out the variant frequency. Results: 1Wa, 1Wb and 2Wa methods of GPA assay were developed. Erythrocytes of MN type individuals could be separated to normal and single locus variant groups by 1W methods and they could be sorted as normal (MN), single gene deletion mutants (MO, NO), homozygous mutants (MM, NN) cell groups by 2Wa method. Conclusion: The assay is applicable to evaluating the frequency of variant erythrocytes from human somatic mutation

Quantitative comparison of in house irma/ria methods using reagents supplied in bulk with assays based on commercial kits

International Nuclear Information System (INIS)

Sajid, K.M.; Jafri, S.R.A.

1997-01-01

Due to high cost of commercial kit assays, local trials were started to establish low cost immunoassay techniques at MINAR, Multan. First available alternate of commercial kits was the use of matched reagents supplied in bulk by NETRIA through INMOL, Lahore under IAEA assistance. As quality is crucial in RIA estimations this laboratory collected passive quality control data of 50, 51 and 52 in-house assay batches of T3,T4 and TSH to compare with the same number of last Amerlex RIAs(successive lots). A qualitative comparison based on computerized data analysis shows linear correlation between the results of two assay systems with low and acceptable precision in T3 and T4 assays. In TSH assays both systems show high imprecision although Amerlex RIA system is relatively more precise than in-house TSH- IRMA. T3 and T4 assays in both the systems show wide working ranges covering all clinical regions. In TSH, working ranges of both the techniques do not cover all clinical regions. In-house TSH assay excludes below 5.5 mulU/ml, whereas Amerlex excludes levels below 4.5 mulL/ml. This may reduce the clinical efficacy of these tests. Amerlex-M T3 and T4 assays show high negative drift with relatively less between variation, whereas in-house assays show low positive drift with high between batch variation. (author)

A novel mean-centering method for normalizing microRNA expression from high-throughput RT-qPCR data

Directory of Open Access Journals (Sweden)

Wylie Dennis

2011-12-01

Full Text Available Abstract Background Normalization is critical for accurate gene expression analysis. A significant challenge in the quantitation of gene expression from biofluids samples is the inability to quantify RNA concentration prior to analysis, underscoring the need for robust normalization tools for this sample type. In this investigation, we evaluated various methods of normalization to determine the optimal approach for quantifying microRNA (miRNA expression from biofluids and tissue samples when using the TaqMan® Megaplex™ high-throughput RT-qPCR platform with low RNA inputs. Findings We compared seven normalization methods in the analysis of variation of miRNA expression from biofluid and tissue samples. We developed a novel variant of the common mean-centering normalization strategy, herein referred to as mean-centering restricted (MCR normalization, which is adapted to the TaqMan Megaplex RT-qPCR platform, but is likely applicable to other high-throughput RT-qPCR-based platforms. Our results indicate that MCR normalization performs comparable to or better than both standard mean-centering and other normalization methods. We also propose an extension of this method to be used when migrating biomarker signatures from Megaplex to singleplex RT-qPCR platforms, based on the identification of a small number of normalizer miRNAs that closely track the mean of expressed miRNAs. Conclusions We developed the MCR method for normalizing miRNA expression from biofluids samples when using the TaqMan Megaplex RT-qPCR platform. Our results suggest that normalization based on the mean of all fully observed (fully detected miRNAs minimizes technical variance in normalized expression values, and that a small number of normalizer miRNAs can be selected when migrating from Megaplex to singleplex assays. In our study, we find that normalization methods that focus on a restricted set of miRNAs tend to perform better than methods that focus on all miRNAs, including

Average of delta: a new quality control tool for clinical laboratories.

Science.gov (United States)

Jones, Graham R D

2016-01-01

Average of normals is a tool used to control assay performance using the average of a series of results from patients' samples. Delta checking is a process of identifying errors in individual patient results by reviewing the difference from previous results of the same patient. This paper introduces a novel alternate approach, average of delta, which combines these concepts to use the average of a number of sequential delta values to identify changes in assay performance. Models for average of delta and average of normals were developed in a spreadsheet application. The model assessed the expected scatter of average of delta and average of normals functions and the effect of assay bias for different values of analytical imprecision and within- and between-subject biological variation and the number of samples included in the calculations. The final assessment was the number of patients' samples required to identify an added bias with 90% certainty. The model demonstrated that with larger numbers of delta values, the average of delta function was tighter (lower coefficient of variation). The optimal number of samples for bias detection with average of delta was likely to be between 5 and 20 for most settings and that average of delta outperformed average of normals when the within-subject biological variation was small relative to the between-subject variation. Average of delta provides a possible additional assay quality control tool which theoretical modelling predicts may be more valuable than average of normals for analytes where the group biological variation is wide compared with within-subject variation and where there is a high rate of repeat testing in the laboratory patient population. © The Author(s) 2015.

Relational Stability in the Expression of Normality, Variation, and Control of Thyroid Function

Science.gov (United States)

Hoermann, Rudolf; Midgley, John E. M.; Larisch, Rolf; Dietrich, Johannes W.

2016-01-01

Thyroid hormone concentrations only become sufficient to maintain a euthyroid state through appropriate stimulation by pituitary thyroid-stimulating hormone (TSH). In such a dynamic system under constant high pressure, guarding against overstimulation becomes vital. Therefore, several defensive mechanisms protect against accidental overstimulation, such as plasma protein binding, conversion of T4 into the more active T3, active transmembrane transport, counter-regulatory activities of reverse T3 and thyronamines, and negative hypothalamic–pituitary–thyroid feedback control of TSH. TSH has gained a dominant but misguided role in interpreting thyroid function testing in assuming that its exceptional sensitivity thereby translates into superior diagnostic performance. However, TSH-dependent thyroid disease classification is heavily influenced by statistical analytic techniques such as uni- or multivariate-defined normality. This demands a separation of its conjoint roles as a sensitive screening test and accurate diagnostic tool. Homeostatic equilibria (set points) in healthy subjects are less variable and do not follow a pattern of random variation, rather indicating signs of early and progressive homeostatic control across the euthyroid range. In the event of imminent thyroid failure with a reduced FT4 output per unit TSH, conversion efficiency increases in order to maintain FT3 stability. In such situations, T3 stability takes priority over set point maintenance. This suggests a concept of relational stability. These findings have important implications for both TSH reference limits and treatment targets for patients on levothyroxine. The use of archival markers is proposed to facilitate the homeostatic interpretation of all parameters. PMID:27872610

An improved method for the assay of platelet pyruvate dehydrogenase

International Nuclear Information System (INIS)

Schofield, P.J.; Griffiths, L.R.; Rogers, S.H.

1980-01-01

An improved method for the assay of human platelet pyruvate dehydrogenase is described. By generating the substrate [1- 14 C]pyruvate in situ from [1- 14 C]lactate plus L-lactate dehydrogenase, the rate of spontaneous decarboxylation is dramatically reduced, allowing far greater sensitivity in the assay of low activities of pyruvate dehydrogenase. In addition, no special precautions are required for the storage and use of [1- 14 C]lactate, in contrast to those for [1- 14 C]pyruvate. These factors allow a 5-10-fold increase in sensitivity compared with current methods. The pyruvate dehydrogenase activity of normal subjects as determined by the [1- 14 C]lactate system was 215+-55 pmol min -1 mg -1 protein (n=18). The advantages of this assay system are discussed. (Auth.)

Effect of reagins and allergen extracts on radioallergosorbent assays for mite allergen

International Nuclear Information System (INIS)

Tovey, E.R.; Vandenberg, R.A.

1978-01-01

The reproducibility of the radioallergosorbent (RAST) inhibition and direct binding assays with mite allergen were investigated in the presence of heterogeneous extracts and non-mite sensitive atopic sera. Both contain components similar to potential contaminants which would occur in the assay of mite allergen and dust allergen extracts. The standardized inhibition and direct binding assays employed had a day to day (n = 4) coefficient of variation [(s.d. x 100)/mean] of 15% and 24% respectively. The inhibition assay for mite allergen was reproducible in the presence of protein concentrations of added plant, fungal, arthropod and animal extracts in excess of the protein concentrations that occur under the operational mite assay conditions. The mite inhibition assay was also reproducible in the presence of non-mite allergen extracts, with and without additional sera containing IgE specific for the non0mite allergens. The binding of a constant quantity of mite allergen to the activated solid phase in the direct binding assay was reproducible in the presence of added bovine serum albumin, and of a fungal or arthropod extract, representing the heterogeneous components of an allergen extract at the concentrations of total protein known to occur in the direct binding assay of mite extracts. (author)

Assay to detect lipid peroxidation upon exposure to nanoparticles.

Science.gov (United States)

Potter, Timothy M; Neun, Barry W; Stern, Stephan T

2011-01-01

This chapter describes a method for the analysis of human hepatocarcinoma cells (HEP G2) for lipid peroxidation products, such as malondialdehyde (MDA), following treatment with nanoparticle formulations. Oxidative stress has been identified as a likely mechanism of nanoparticle toxicity, and cell-based in vitro systems for evaluation of nanoparticle-induced oxidative stress are widely considered to be an important component of biocompatibility screens. The products of lipid peroxidation, lipid hydroperoxides, and aldehydes, such as MDA, can be measured via a thiobarbituric acid reactive substances (TBARS) assay. In this assay, which can be performed in cell culture or in cell lysate, MDA combines with thiobarbituric acid (TBA) to form a fluorescent adduct that can be detected at an excitation wavelength of 530 nm and an emission wavelength of 550 nm. The results are then expressed as MDA equivalents, normalized to total cellular protein (determined by Bradford assay).

Normal variation in thermal radiated temperature in cattle: implications for foot-and-mouth disease detection

Directory of Open Access Journals (Sweden)

Gloster John

2011-11-01

Full Text Available Abstract Background Thermal imagers have been used in a number of disciplines to record animal surface temperatures and as a result detect temperature distributions and abnormalities requiring a particular course of action. Some work, with animals infected with foot-and-mouth disease virus, has suggested that the technique might be used to identify animals in the early stages of disease. In this study, images of 19 healthy cattle have been taken over an extended period to determine hoof and especially coronary band temperatures (a common site for the development of FMD lesions and eye temperatures (as a surrogate for core body temperature and to examine how these vary with time and ambient conditions. Results The results showed that under UK conditions an animal's hoof temperature varied from 10°C to 36°C and was primarily influenced by the ambient temperature and the animal's activity immediately prior to measurement. Eye temperatures were not affected by ambient temperature and are a useful indicator of core body temperature. Conclusions Given the variation in temperature of the hooves of normal animals under various environmental conditions the use of a single threshold hoof temperature will be at best a modest predictive indicator of early FMD, even if ambient temperature is factored into the evaluation.

Studies on the 2-site immunoradiometric assay of serum ferritin and its applications for diagnosis of iron deficiency

Energy Technology Data Exchange (ETDEWEB)

Koseki, J.; Niitsu, Y. (Sapporo Medical Coll. (Japan). Cancer Research Inst.)

1980-10-01

The 2-site immunoradiometric assay using paper discs as a solid phase material was established for the measurement of serum ferritin. The standard curve was found the range from 0.5ng -- 500ng ferritin per ml and the sensitivity limit of the assay was 0.1ng ferritin per ml. The clinical value of serum ferritin assay was then investigated for diagnosis of iron deficiency. The mean serum ferritin concentrations of normal subjects were greater for males (119.8+-55.5ng/ml) than for females (56.5+-55.5ng/ml) although this sex difference was not distinct beyond the age of 45. All 15 patients with iron deficient anemia had serum ferritin concentrations below the normal range, whereas in other anemias including anemia associated with chronic inflammation, pernicious anemia, aplastic anemia, serum ferritin concentrations were normal or elevated. In 116 apparently normal subjects, 13.8% of total females had abnormally low serum ferritin concentrations with normal hemoglobin levels. The cytochrome c oxidase activity of peripheral leucocytes from those subjects were generally depleted. Most of them frequently suffered from easy fatigability, weakness, and dizziness and these complications were clearly relieved by the administration of iron. Measurement of serum ferritin was found to be quite useful for diagnosis and assessment of iron deficient states.

The influence of the number of cells scored on the sensitivity in the comet assay

DEFF Research Database (Denmark)

Sharma, Anoop Kumar; Soussaline, Françoise; Sallette, Jerome

2012-01-01

The impact on the sensitivity of the in vitro comet assay by increasing the number of cells scored has only been addressed in a few studies. The present study investigated whether the sensitivity of the assay could be improved by scoring more than 100 cells. Two cell lines and three different che...... of the assay. A two-way ANOVA analysis of variance showed that the contribution from the two variables “the number of cells scored” and “concentration” on the total variation in the coefficients of variance dataset was statistically significant (p...

Heterophilic antibody interference affecting multiple hormone assays: Is it due to rheumatoid factor?

Science.gov (United States)

Mongolu, Shiva; Armston, Annie E; Mozley, Erin; Nasruddin, Azraai

2016-01-01

Assay interference with heterophilic antibodies has been well described in literature. Rheumatoid factor is known to cause similar interference leading to falsely elevated hormone levels when measured by immunometric methods like enzyme-linked immunosorbent assay (ELISA) or multiplex immunoasays (MIA). We report a case of a 60-year-old male patient with a history of rheumatoid arthritis referred to our endocrine clinic for investigation of hypogonadism and was found to have high serum levels of LH, FSH, SHBG, Prolactin, HCG and TSH. We suspected assay interference and further tests were performed. We used Heteroblock tubes and PEG precipitation to eliminate the interference and the hormone levels post treatment were in the normal range. We believe the interference was caused by high serum levels of rheumatoid factor. Although he was treated with thyroxine for 3 years, we believe he may have been treated inappropriately as his Free T4 level was always normal despite high TSH due to assay interference. Our case illustrates the phenomenon of heterophilic antibody interference likely due to high levels of rheumatoid factor. It is essential for clinicians and endocrinologists in particular to be aware of this possibility when making treatment decisions in these groups of patients.

Effective Normalization for Copy Number Variation Detection from Whole Genome Sequencing

NARCIS (Netherlands)

Janevski, A.; Varadan, V.; Kamalakaran, S.; Banerjee, N.; Dimitrova, D.

2012-01-01

Background Whole genome sequencing enables a high resolution view ofthe human genome and provides unique insights into genome structureat an unprecedented scale. There have been a number of tools to infer copy number variation in the genome. These tools while validatedalso include a number of

Normal variants and non-pathologic findings of the skeletal system in childhood

International Nuclear Information System (INIS)

Schaper, J.; Heinen, W.

2006-01-01

The knowledge of normal variants of the skeletal system in childhood protects the child from false radiologic diagnosis and the resulting malpractice. In this article we present a survey of common variants of childhood skeletal system. The awareness of these entities, e. g. the benign extraaxial fluid collections of infancy, allows accurate clinical and radiological diagnosis. The most important impact of radiological expertise in normal variations results in avoidance of unneccessary examinations and in omission of unsubstantiated parental and patients fears. Nearly all normal variations with definite radiologic findings should be treated according to the ''leave-me-alone'' principle. (orig.)

Radiogenomics: predicting clinical normal tissue radiosensitivity

DEFF Research Database (Denmark)

Alsner, Jan

2006-01-01

Studies on the genetic basis of normal tissue radiosensitivity, or  'radiogenomics', aims at predicting clinical radiosensitivity and optimize treatment from individual genetic profiles. Several studies have now reported links between variations in certain genes related to the biological response...... to radiation injury and risk of normal tissue morbidity in cancer patients treated with radiotherapy. However, after these initial association studies including few genes, we are still far from being able to predict clinical radiosensitivity on an individual level. Recent data from our own studies on risk...

Short Communication: Comparison of Maxim and Sedia Limiting Antigen Assay Performance for Measuring HIV Incidence.

Science.gov (United States)

Schlusser, Katherine E; Konikoff, Jacob; Kirkpatrick, Allison R; Morrison, Charles; Chipato, Tsungai; Chen, Pai-Lien; Munjoma, Marshall; Eshleman, Susan H; Laeyendecker, Oliver

2017-06-01

Accurate methods for cross-sectional incidence estimation are needed for HIV prevention research. The Limiting Antigen Avidity (LAg-Avidity) assay has been marketed by two vendors, Maxim Biomedical and Sedia BioSciences Corporation. Performance differences between the two versions of the assay are unknown. We tested a total 1,410 treatment-naive samples with both versions of the assay. The samples came from 176 seroconverters from the Zimbabwe Hormonal Contraception and HIV Study. The correlation between the two versions of the assay was 0.93 for the optical density (OD) and 0.86 for the normalized OD. As the difference was more pronounced for the normalized OD, the difference in assays can be attributed to the calibrators. The mean duration of recent infection (MDRI), the average time individuals infected 1,000 copies/ml. The MDRI was 137 days for Sedia and 157 days for Maxim, with a difference of 20 days (95% CI 11-30). The MDRIs decreased to 102 and 120 days with the inclusion of a viral load cutoff of >1,000 copies/ml. These results imply that use of the Sedia LAg-Avidity will result in estimates of incidence ∼13% lower than those using the Maxim LAg-Avidity.

The value of scintimetry compared with histomorphology, parathormone assay, densitometry and radiology in renal osteopathy

International Nuclear Information System (INIS)

Lingg, G.; Nebel, G.; Dorr, S.; Allgemeines Krankenhaus Barmbek, Hamburg

1982-01-01

The value of scintimetry compared with histomorphology, parathormone assay, densitometry and radiology in renal osteopathy. The distribution of sup(99m)Tc-Sn-MDP in the thigh was estimated according to two different indices 60 normal patients, 21 patients undergoing haemodialysis and one who had had a renal transplant. Deviation of the indices in these patients from the normal are significant. The indices were correlated with respect to their accuracy in detecting renal osteopathy with histomorphometry (as the reference method), radiological diagnosis, densitometry, parathormone assay and other laboratory tests. Accuracy of the method is high and, like histomorphometry, is over 9O%. (orig.) [de

Comparison of radioimmunoassay and gas chromatographic mass spectrometric assay for d-amphetamine

International Nuclear Information System (INIS)

Powers, K.H.; Ebert, M.H.

1979-01-01

Quantification of low levels of psychotropic drugs (10 -7 to 10 -9 g ml -1 ) in small volumes of plasma requires sensitive and accurate methods. Validation of these methods is best achieved by comparing results obtained using several techniques. In this study, amphetamine levels in plasma were measured using gas chromatography mass spectrometry and radioimmunoassay. Correlation of the results obtained by the two methods was found to be positive and high (R = 0.9822). The average coefficient of variation between assays for gas chromatography mass spectrometry was 5.8% and for radioimmunoassay was 12.3%, while the average coefficient of variation within assays for gas chromatography mass spectrometry was 4.9% and for radioimmunoassay 6.9%. Although gas chromatography mass spectrometry was 1.9 times more sensitive than radioimmunoassay, for most purposes, the convenience of the radioimmunoassay method outweighs the technical superiority of gas chromatography mass spectrometry. (author)

Differences in otosclerotic and normal human stapedial osteoblast properties are normalized by alendronate in vitro.

Science.gov (United States)

Gronowicz, Gloria; Richardson, Yvonne L; Flynn, John; Kveton, John; Eisen, Marc; Leonard, Gerald; Aronow, Michael; Rodner, Craig; Parham, Kourosh

2014-10-01

Identify and compare phenotypic properties of osteoblasts from patients with otosclerosis (OSO), normal bones (HOB), and normal stapes (NSO) to determine a possible cause for OSO hypermineralization and assess any effects of the bisphosphonate, alendronate. OSO (n = 11), NSO (n = 4), and HOB (n = 13) cultures were assayed for proliferation, adhesion, mineralization, and gene expression with and without 10(-10)M-10(-8)M alendronate. Academic hospital. Cultures were matched for age, sex, and passage number. Cell attachment and proliferation + alendronate were determined by Coulter counting cells and assaying tritiated thymidine uptake, respectively. At 7, 14, and 21 days of culture + alendronate, calcium content and gene expression by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were determined. OSO had significantly more cells adhere but less proliferation than NSO or HOB. Calcification was significantly increased in OSO compared to HOB and NSO. NSO and HOB had similar cell adhesion and proliferation rates. A dose-dependent effect of alendronate on OSO adhesion, proliferation, and mineralization was found, resulting in levels equal to NSO and HOB. All cultures expressed osteoblast-specific genes such as RUNX2, alkaline phosphatase, type I collagen, and osteocalcin. However, osteopontin was dramatically reduced, 9.4-fold at 14 days, in OSO compared to NSO. Receptor activator of nuclear factor κB ligand/osteoprotegerin (RANKL/OPG), important in bone resorption, was elevated in OSO with decreased levels of OPG levels. Alendronate had little effect on gene expression in HOB but in OSO increased osteopontin levels and decreased RANKL/OPG. OSO cultures displayed properties of hypermineralization due to decreased osteopontin (OPN) and also had increased RANKL/OPG, which were normalized by alendronate. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.

Standardizing electrophoresis conditions: how to eliminate a major source of error in the comet assay.

Directory of Open Access Journals (Sweden)

Gunnar Brunborg

2015-06-01

Full Text Available In the alkaline comet assay, cells are embedded in agarose, lysed, and then subjected to further processing including electrophoresis at high pH (>13. We observed very large variations of mean comet tail lengths of cell samples from the same population when spread on a glass or plastic substrate and subjected to electrophoresis. These variations might be cancelled out if comets are scored randomly over a large surface, or if all the comets are scored. The mean tail length may then be representative of the population, although its standard error is large. However, the scoring process often involves selection of 50 – 100 comets in areas selected in an unsystematic way from a large gel on a glass slide. When using our 96-sample minigel format (1, neighbouring sample variations are easily detected. We have used this system to study the cause of the comet assay variations during electrophoresis and we have defined experimental conditions which reduce the variations to a minimum. We studied the importance of various physical parameters during electrophoresis: (i voltage; (ii duration of electrophoresis; (iii electric current; (iv temperature; and (v agarose concentration. We observed that the voltage (V/cm varied substantially during electrophoresis, even within a few millimetres of distance between gel samples. Not unexpectedly, both the potential ( V/cm and the time were linearly related to the mean comet tail, whereas the current was not. By measuring the local voltage with microelectrodes a few millimetres apart, we observed substantial local variations in V/cm, and they increased with time. This explains the large variations in neighbouring sample comet tails of 25% or more. By introducing simple technology (circulation of the solution during electrophoresis, and temperature control, these variations in mean comet tail were largely abolished, as were the V/cm variations. Circulation was shown to be particularly important and optimal conditions

Routine clinical application of the FRAXA Pfu PCR assay: limits and utility.

Science.gov (United States)

Condorelli, D F; Milana, G; Dell'Albani, P; Roccazzello, A M; Insirello, E; Pavone, L; Mollica, F

1996-11-01

Fragile X genotype is characterized by the excessive amplification of an unstable region of DNA: a trinucleotide repeat CGG of variable copy number present in the FRAXA locus. Methods based on polymerase chain reaction (PCR) amplification of the CGG repeat region could facilitate the development of a rapid screening assay. Unfortunately, amplification across CGG repeats can be inefficient and unreliable due to their 100% G + C base composition. The utility of the exonuclease-deficient Pfu polymerase for amplification and detection of the CGG repeats at the FRAXA locus has been reported. In the present study we analysed the utility of a Pfu PCR assay as a rapid initial screening method to rule out a diagnosis of fragile X syndrome in males with mental retardation. Affected males did not show any amplification products or a smear of amplification products between 350 and 550 bp. Only 10% of affected male samples did not show any amplification products, while the vast majority showed the amplification smear. The amplification smears represent a serious drawback of the method, since they cannot be distinguished from the amplification products of normal samples after separation in 1% agarose gel. Several modifications of the PCR conditions were attempted to eliminate this problem, but none was appropriate for clinical applications. However, the problem was easily solved by using a higher resolution electrophoretic system that allows a clear distinction of normal bands from pathological smears. We tested the specificity of the Pfu PCR assay, followed by an improved MetaPhor gel electrophoretic separation of PCR products, on 50 samples from normal males and 24 samples form affected males. The results showed that this method is a rapid, sensitive and specific assay for the exclusion of fragile X syndrome diagnosis in mentally retarded males.

Regulation of heme metabolism in normal and sideroblastic bone marrow cells in culture

International Nuclear Information System (INIS)

Ibraham, N.G.; Lutton, J.D.; Hoffman, R.; Levere, R.D.

1985-01-01

Heme metabolism was examined in developing in vitro erythroid colonies (CFUE) and in bone marrow samples taken directly from four normal donors and four patients with sideroblastic anemia. Maximum activities of delta-aminolevulinic acid synthase (ALAS), ALA dehydratase (ALAD), and 14 C-ALA incorporation into heme were achieved in normal marrow CFUE after 8 days of culture, whereas heme oxygenase progressively decreased to low levels of activity during the same period. Assays on nucleated bone marrow cells taken directly from patients revealed that ALAS activity was considerably reduced in idiopathic sideroblastic anemia (IASA) and X-linked sideroblastic anemia (X-SA) bone marrow specimens, whereas the activity increased more than twofold (normal levels) when cells were assayed from 8-day CFUE. In all cases, ALAD activity appeared to be within normal levels. Measurement of heme synthesis revealed that normal levels of 14 C-ALA incorporation into heme were achieved in IASA cells but were reduced in X-SA cells. In marked contrast to levels in normal cells, heme oxygenase was found to be significantly elevated (two- to fourfold) in bone marrow cells taken directly from patients with IASA and X-SA. Results from this study demonstrate that IASA and X-SA bone marrow cells have disturbances in ALAS and heme metabolism, and that erythropoiesis (CFUE) can be restored to normal levels when cells are cultured in methylcellulose

Radioligand purification prior to routine receptor assays

International Nuclear Information System (INIS)

Le Goff, J.-M.; Berthois, Y.; Martin, P.-M.

1988-01-01

The need to repurify the commercially available radioligands [ 3 H]estradiol and [ 3 H]testosterone before use in routine assays was investigated. Storage of these products for 2 months after delivery led to appreciable degradation of [ 3 H]estradiol compared to [ 3 H]testosterone. Unexpectedly, TLC and even HPLC procedures were ineffective in completely restoring the purity of [ 3 H]-estradiol and the unremoved polar products induced important variations in our estrogen receptor assays. An increase in non-specific binding and a concomitant decrease in total binding were observed resulting in an underestimation of specific binding sites and of the affinity constant. In some cases Scatchard analysis was not possible. The authors therefore strongly recommend the repurification of low-stability radioligands and propose an economic time-saving procedure for the purification of [ 3 H]estradiol by solvent differential partition which requires no high-cost investment in apparatus. (author)

Sample normalization methods in quantitative metabolomics.

Science.gov (United States)

Wu, Yiman; Li, Liang

2016-01-22

To reveal metabolomic changes caused by a biological event in quantitative metabolomics, it is critical to use an analytical tool that can perform accurate and precise quantification to examine the true concentration differences of individual metabolites found in different samples. A number of steps are involved in metabolomic analysis including pre-analytical work (e.g., sample collection and storage), analytical work (e.g., sample analysis) and data analysis (e.g., feature extraction and quantification). Each one of them can influence the quantitative results significantly and thus should be performed with great care. Among them, the total sample amount or concentration of metabolites can be significantly different from one sample to another. Thus, it is critical to reduce or eliminate the effect of total sample amount variation on quantification of individual metabolites. In this review, we describe the importance of sample normalization in the analytical workflow with a focus on mass spectrometry (MS)-based platforms, discuss a number of methods recently reported in the literature and comment on their applicability in real world metabolomics applications. Sample normalization has been sometimes ignored in metabolomics, partially due to the lack of a convenient means of performing sample normalization. We show that several methods are now available and sample normalization should be performed in quantitative metabolomics where the analyzed samples have significant variations in total sample amounts. Copyright © 2015 Elsevier B.V. All rights reserved.

Standardization of a cytometric p24-capture bead-assay for the detection of main HIV-1 subtypes.

Science.gov (United States)

Merbah, Mélanie; Onkar, Sayali; Grivel, Jean-Charles; Vanpouille, Christophe; Biancotto, Angélique; Bonar, Lydia; Sanders-Buell, Eric; Kijak, Gustavo; Michael, Nelson; Robb, Merlin; Kim, Jerome H; Tovanabutra, Sodsai; Chenine, Agnès-Laurence

2016-04-01

The prevailing method to assess HIV-1 replication and infectivity is to measure the production of p24 Gag protein by enzyme-linked immunosorbent assay (ELISA). Since fluorescent bead-based technologies offer a broader dynamic range and higher sensitivity, this study describes a p24 capture Luminex assay capable of detecting HIV-1 subtypes A-D, circulating recombinant forms (CRF) CRF01_AE and CRF02_AG, which together are responsible for over 90% of HIV-1 infections worldwide. The success of the assay lies in the identification and selection of a cross-reactive capture antibody (clone 183-H12-5C). Fifty-six isolates that belonged to six HIV-1 subtypes and CRFs were successfully detected with p-values below 0.021; limits of detection ranging from 3.7 to 3 × 104 pg/ml. The intra- and inter-assay variation gave coefficient of variations below 6 and 14%, respectively. The 183-bead Luminex assay also displayed higher sensitivity of 91% and 98% compared to commercial p24 ELISA and a previously described Luminex assay. The p24 concentrations measured by the 183-bead Luminex assay showed a significant correlation (R=0.92, passay leverages the advantages of the Luminex platform, which include smaller sample volume and simultaneous detection of up to 500 analytes in a single sample, and delivers a valuable tool for the field. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of a Homogenous Assay for the Detection of 2,4,6-Trinitrotoluene to Environmental Water Samples

Directory of Open Access Journals (Sweden)

Ellen R. Goldman

2005-01-01

Full Text Available A homogeneous assay was used to detect 2,4,6-trinitrotoluene (TNT spiked into environmental water samples. This assay is based on changes in fluorescence emission intensity when TNT competitively displaces a fluorescently labeled, TNT analog bound to an anti-TNT antibody. The effectiveness of the assay was highly dependent on the source of the sample being tested. As no correlation between pH and assay performance was observed, ionic strength was assumed to be the reason for variation in assay results. Addition of 10x phosphate-buffered saline to samples to increase their ionic strength to that of our standard laboratory buffer (about 0.17 M significantly improved the range over which the assay functioned in several river water samples.

Sonographic Measurement of Normal Splenic Length in Korean Adults

Energy Technology Data Exchange (ETDEWEB)

Shin, Sang Bum; Cheon, Byung Kook; Kim, Jong Min; Oh, Kyung Seoung; Jung, Gyoo Sik; Huh, Jin Do; Joh, Young Duk [Kosin University College of Medicine, Busan (Korea, Republic of)

1996-12-15

To establish upper limit of normal splenic length of Korean adults on ultrasonography and to determice the degree of interobserver and intraobserver variation. Ultrasonographic scans were performed to measure the maximum length of spleen in 105 of 150 adults selected by convenience sampling. Remained 45 cases with any conditions that could alter splenic size were excluded from this study. The maximum length of spleen was measured and correlated with body surface area, patient height, weight, age and sex. In 31 of the 105 adults we evaluated the interobserver and intraobserver variations in sonographic measurements of splenic length obtained by three radiologists in blind fashion. The mean splenic length in 105 adults was 8.56cm ({+-} 0.95). The splenic length positively correlated with body surface area, patient height and weight (P <0.001), and negatively correlated with patient age (P < 0.01). Male spleen (8.87 cm {+-} 1.07) was longer than female spleen (8.35 cm {+-} 0.81) (P < 0.05). The following guidelines are proposed for the upper limit of normal splenic length at different groups of body surface area: no longer than 10 cm at 1.20{approx}1.59 m{sup 2}, 11 cm at1.60{approx}1.79 m{sup 2}, and 12 cm at 1.80{approx}1.99 m{sup 2}. The mean interobserver variation between any two radiologists ranged from 0.32 cm ({+-} 0.29) to 0.39 cm ({+-} 0.33) and interobserver variations were within 1 cm in 96%. The mean intraobserver variations were within 0.5 cm in 91%. The splenic length closely correlated with body surface area, patient height, weight and age. Particularly the upper limit of normal splenic length changed according to body surface area. Interobserver variation about 1 cm and intraobserver variation about 0.5 cm should be considered in the measurement of the splenic length on ultrasonography

Relationship between in vitro chromosomal radiosensitivity of peripheral blood lymphocytes and the expression of normal tissue damage following radiotherapy for breast cancer

International Nuclear Information System (INIS)

Barber, J.B.P.; Burrill, W.; Spreadborough, A.R.; Levine, E.; Warren, C.; Scott, D.; Kiltie, A.E.; Roberts, S.A.

2000-01-01

There is a need for rapid and reliable tests for the prediction of normal tissue responses to radiotherapy, as this could lead to individualization of patient radiotherapy schedules and thus improvements in the therapeutic ratio. Because the use of cultured fibroblasts is too slow to be practicable in a clinical setting, we evaluated the predictive role of assays of lymphocyte chromosomal radiosensitivity in patients having radiotherapy for breast cancer. Radiosensitivity was assessed using a macronucleus (MN) assay at high dose rate (HDR) and low dose rate (LDR) on lymphocytes irradiated in the G 0 phase of the cell cycle (Scott D, Barber JB, Levine EL, Burril W, Roberts SA. Radiation-induced micronucleus induction in lymphocytes identifies a frequency of radiosensitive cases among breast cancer patients: a test for predisposition? Br. J. Cancer 1998;77;614-620) and an assay of G 2 phase chromatid radiosensitivity ('G 2 assay') (Scott D, Spreadborough A, Levine E, Roberts SA. Genetic predisposition in breast cancer. Lancet 1994; 344: 1444). In a study of acute reactions, blood samples were taken from breast cancer patients before the start of radiotherapy, and the skin reaction documented. 116 patients were tested with the HDR MN assay, 73 with the LDR MN assay and 123 with the G 2 assay. In a study of late reactions, samples were taken from a series of breast cancer patients 8-14 years after radiotherapy and the patients assessed for the severity of late effects according to the 'LENT SOMA' scales. 47 were tested with the HDR assay, 26 with the LDR assay and 19 with the G 2 assay. For each clinical endpoint, patients were classified as being normal reactors or 'highly radiosensitive patients' (HR patients (Burnet NG. Johansen J, Turesson I, Nyman J. Describing patients' normal tissue reactions: Concerning the possibility of individualising radiotherapy dose prescriptions based on potential predictive assays of normal tissue radiosensitivity. Int. J. Cancer 1998

Longitudinal study of serum placental GH in 455 normal pregnancies

DEFF Research Database (Denmark)

Chellakooty, Marla; Skibsted, Lillian; Skouby, Sven O

2002-01-01

women with normal singleton pregnancies at approximately 19 and 28 wk gestation. Serum placental GH concentrations were measured by a highly specific immunoradiometric assay, and fetal size was measured by ultrasound. Data on birth weight, gender, prepregnancy body mass index (BMI), parity, and smoking...

The evaluation of domestic immunoradiometric assay kit for alpha-fetoprotein

International Nuclear Information System (INIS)

Won, Kyoung Sook; Ryu, Jin Sook; Moon, Dae Hyuk; Lee, Hee Kyung

2000-01-01

Although α-fetoprotein is one of the most commonly used tumor markers in Korea, most of the radioimmunoassay kits for α-fetoprotein have been imported from foreign countries. The purpose of this study was to evaluate the performance of a recently developed domestic immunoradiometric kit for α-fetoprotein (Riakey AFP IRMA CT R , Sin-Jin Medics, Seoul, Korea). We evaluated intra-and inter-assay precision, recovery rate, parallelism, and sensitivity of serum α-fetoprotein measurement using Riakey AFP IRMA CT R kit. The values of α-fetoprotein measured by Riakey AFP IRMA CT R kit were compared with those measured by two foreign commercial kits (α-fetoproteina of Radim and α-feto.riabead of Abbott). Intra-assay coefficients of variation on three different levels were 5.3% for 18.9 ng/ml, 3.4% for 133 ng/ml and 1.6% for 330 ng/ml. Inter-assay coefficients of variation were 9.7% for 20.9 ng/ml, 3.2% for 137 ng/ml and 4.1% for 330 ng/ml respectively. Recovery rate tests on all three different levels showed within 100±10%. Parallelism was also good and the sensitivity was 0.63 ng/ml. There was strong correlation between the measurement of α-fetoprotein by Riakey AFP IRMA CT R and that by two foreign commercial kits(r=3D0.98). The first Korean domestic immunoradiometric kit for α-fetoprotein, Riakey AFP IRMA CT R , performed well for clinical use.=20

Evaluation of the reliability of maize reference assays for GMO quantification.

Science.gov (United States)

Papazova, Nina; Zhang, David; Gruden, Kristina; Vojvoda, Jana; Yang, Litao; Buh Gasparic, Meti; Blejec, Andrej; Fouilloux, Stephane; De Loose, Marc; Taverniers, Isabel

2010-03-01

A reliable PCR reference assay for relative genetically modified organism (GMO) quantification must be specific for the target taxon and amplify uniformly along the commercialised varieties within the considered taxon. Different reference assays for maize (Zea mays L.) are used in official methods for GMO quantification. In this study, we evaluated the reliability of eight existing maize reference assays, four of which are used in combination with an event-specific polymerase chain reaction (PCR) assay validated and published by the Community Reference Laboratory (CRL). We analysed the nucleotide sequence variation in the target genomic regions in a broad range of transgenic and conventional varieties and lines: MON 810 varieties cultivated in Spain and conventional varieties from various geographical origins and breeding history. In addition, the reliability of the assays was evaluated based on their PCR amplification performance. A single base pair substitution, corresponding to a single nucleotide polymorphism (SNP) reported in an earlier study, was observed in the forward primer of one of the studied alcohol dehydrogenase 1 (Adh1) (70) assays in a large number of varieties. The SNP presence is consistent with a poor PCR performance observed for this assay along the tested varieties. The obtained data show that the Adh1 (70) assay used in the official CRL NK603 assay is unreliable. Based on our results from both the nucleotide stability study and the PCR performance test, we can conclude that the Adh1 (136) reference assay (T25 and Bt11 assays) as well as the tested high mobility group protein gene assay, which also form parts of CRL methods for quantification, are highly reliable. Despite the observed uniformity in the nucleotide sequence of the invertase gene assay, the PCR performance test reveals that this target sequence might occur in more than one copy. Finally, although currently not forming a part of official quantification methods, zein and SSIIb

Pentobarbital quantitation using EMIT serum barbiturate assay reagents: application to monitoring of high-dose pentobarbital therapy.

Science.gov (United States)

Pape, B E; Cary, P L; Clay, L C; Godolphin, W

1983-01-01

Pentobarbital serum concentrations associated with a high-dose therapeutic regimen were determined using EMIT immunoassay reagents. Replicate analyses of serum controls resulted in a within-assay coefficient of variation of 5.0% and a between-assay coefficient of variation of 10%. Regression analysis of 44 serum samples analyzed by this technique (y) and a reference procedure (x) were y = 0.98x + 3.6 (r = 0.98; x = ultraviolet spectroscopy) and y = 1.04x + 2.4 (r = 0.96; x = high-performance liquid chromatography). Clinical evaluation of the results indicates the immunoassay is sufficiently sensitive and selective for pentobarbital to allow accurate quantitation within the therapeutic range associated with high-dose therapy.

Cell-mediated cytotoxicity for melanome tumor cells: detection by a (3H)proline release assay

International Nuclear Information System (INIS)

Saal, J.G.; Rieber, E.P.; Riethmueller, G.

1976-01-01

An in vitro lymphocyte-mediated cytotoxicity assay using [ 3 H]proline-labelled target cells is described. The assay, modified from an original procedure of Bean et al., assesses the release of [ 3 H]proline by filtering the total culture fluid containing both trypsinised tumor cells and effector cells. Filtration is performed with a semiautomatic harvesting device using low suction pressure and large-diameter glass filters. Pretreatment of filters with whole serum diminishes adsorption of cell-free radioactive material considerably and thus increases the sensitivity of the assay. Nearly 100% of the radioactivity could be recovered with this harvesting device. The technique allowed the detection of cytolytic activities of lymphocytes after 6 h of incubation. Lymphocytes from patients with primary malignant melanoma showed a significantly higher cytolytic reactivity (p > 0.001) than normal donors' lymphocytes against three different melanoma cell lines. In a series of parallel experiments on 36 patients and 18 normal donors, this modification of the [ 3 ]proline test was compared with three different assays: the conventional microcytotoxicity test of Takasugi and Klein, the original [ 3 H]proline microcytotoxicity test of Bean et al., and the viability count of tumor cells. (Auth.)

Studies on the 2-site immunoradiometric assay of serum ferritin and its applications for diagnosis of iron deficiency

International Nuclear Information System (INIS)

Koseki, Junichi; Niitsu, Yoshiro

1980-01-01

The 2-site immunoradiometric assay using paper discs as a solid phase material was established for the measurement of serum ferritin. The standard curve was found the range from 0.5ng -- 500ng ferritin per ml and the sensitivity limit of the assay was 0.1ng ferritin per ml. The clinical value of serum ferritin assay was then investigated for diagnosis of iron deficiency. The mean serum ferritin concentrations of normal subjects were greater for males (119.8+-55.5ng/ml) than for females (56.5+-55.5ng/ml) although this sex difference was not distinct beyond the age of 45. All 15 patients with iron deficient anemia had serum ferritin concentrations below the normal range, whereas in other anemias including anemia associated with chronic inflammation, pernicious anemia, aplastic anemia, serum ferritin concentrations were normal oe elevated. In 116 apparently normal subjects, 13.8% of total females had abnormally low serum ferritin concentrations with normal hemoglobin levels. The cytochrome c oxidase activity of peripheral leucocytes from those subjects were generally depleted. Most of them frequently suffered from easy fatiguability, weakness, and dizziness and these complications were clearly relieved by the administration of iron. Measurement of serum ferritin was found to be quite useful for diagnosis and assessment of iron deficient states. (author)

Evaluation of the Thermo Scientific™ SureTect™ Listeria species Assay.

Science.gov (United States)

Cloke, Jonathan; Evans, Katharine; Crabtree, David; Hughes, Annette; Simpson, Helen; Holopainen, Jani; Wickstrand, Nina; Kauppinen, Mikko

2014-03-01

The Thermo Scientific™ SureTect™ Listeria species Assay is a new real-time PCR assay for the detection of all species of Listeria in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested MethodsSM program to validate the SureTect Listeria species Assay in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996 including amendment 1:2004 in a variety of foods plus plastic and stainless steel. The food matrixes validated were smoked salmon, processed cheese, fresh bagged spinach, cantaloupe, cooked prawns, cooked sliced turkey meat, cooked sliced ham, salami, pork frankfurters, and raw ground beef. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, three matrixes (pork frankfurters, fresh bagged spinach, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled independent laboratory study by the University of Guelph, Canada. Using probability of detection statistical analysis, a significant difference in favour of the SureTect assay was demonstrated between the SureTect and reference method for high level spiked samples of pork frankfurters, smoked salmon, cooked prawns, stainless steel, and low-spiked samples of salami. For all other matrixes, no significant difference was seen between the two methods during the study. Inclusivity testing was conducted with 68 different isolates of Listeria species, all of which were detected by the SureTect Listeria species Assay. None of the 33 exclusivity isolates were detected by the SureTect Listeria species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation, which demonstrated that the assay gave reliable performance. Accelerated stability testing was additionally conducted, validating the

Evaluation of the Thermo Scientific SureTect Listeria monocytogenes Assay.

Science.gov (United States)

Cloke, Jonathan; Leon-Velarde, Carlos; Larson, Nathan; Dave, Keron; Evans, Katharine; Crabtree, David; Hughes, Annette; Hopper, Craig; Simpson, Helen; Withey, Sophie; Oleksiuk, Milena; Holopainen, Jani; Wickstrand, Nina; Kauppinen, Mikko

2014-01-01

The Thermo Scientific SureTect Listeria monocytogenes Assay is a new real-time PCR assay for the detection of Listeria monocytogenes in food and environmental samples. This assay was validated using the AOAC Research Institute (AOAC-RI) Performance Tested Methods program in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996, including Amendment 1:2004 with the following foods and food contact surfaces: smoked salmon, processed cheese, fresh bagged spinach, fresh cantaloupe, cooked prawns (chilled product), cooked sliced turkey meat (chilled product), ice cream, pork frankfurters, salami, ground raw beef meat (12% fat), plastic, and stainless steel. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, three matrixes (pork frankfurters, bagged lettuce, and stainless steel) were analyzed independently as part of the AOAC-RI controlled laboratory study by the University of Guelph, Canada. Using probability of detection (POD) statistical analysis, a significant difference was demonstrated between the candidate and reference methods for salami, cooked sliced turkey and ice cream in favor of the SureTect assay. For all other matrixes, no significant difference by POD was seen between the two methods during the study. Inclusivity and exclusivity testing was also conducted with 53 and 30 isolates, respectively, which demonstrated that the SureTect assay was able to detect all serotypes of L. monocytogenes. None of the exclusivity isolates analyzed were detected by the SureTect assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside the recommended parameters open to variation, i.e., enrichment time and temperature and lysis temperature, which demonstrated that the assay gave reliable performance. Accelerated stability testing was also conducted, validating the assay shelf life.

Comparison of monoclonal antibodies and tritiated ligands for estrogen receptor assays in 241 breast cancer cytosols

International Nuclear Information System (INIS)

Goussard, J.; Lechevrel, C.; Martin, P.M.; Roussel, G.

1986-01-01

Estrogen receptor determinations have been performed on 241 cytosols from 160 breast cancer tumors using both radioactive ligands ([ 3 H]-estradiol, [3H]R2858) and monoclonal antibodies (Abbott ER-EIA Kit) to compare the two methods and to evaluate the clinical usefulness of the new immunological, simplified assay. Intra- and interassay reproducibility of the enzyme immunoassay (EIA) method was studied during a 6-month period on 35 standard curves with 4 different batches of monoclonal antibodies. Intraassay coefficients of variation studied on duplicates were smaller than 5% in most cases and reproducibility of the curves showed coefficients of variation lower than 10% except for standard 0 and 5 fmol/ml. Pooled cytosols used as control for the dextran coated charcoal method had interassay variation coefficients between 3.8 and 11.4%. Reproducibility has been studied on clinical specimens assayed twice at two different periods with either EIA or dextran coated charcoal methods. Slopes obtained were 1.05 and 0.96, respectively. A good stability of EIA results was obtained with protein concentrations in the range 4-0.15 mg/ml cytosol. No significant effects of dithiothreitol or monothioglycerol (1 mM) on EIA and dextran coated charcoal assay were observed. Eighty breast cancer cytosols were assayed with both EIA and Scatchard analysis. The slope of the regression curve obtained was 1.04 (r = 0.963). Cytosols were assayed by EIA and by a saturating concentration of tritiated ligand (5 nM). With 153 cytosols the EIA/5 nM slope was 1.34 (r = 0.978). This slope can be compared with the slope Scatchard/5 nM obtained with 90 cytosols: 1.29 (r = 0.985). Absence of cross-reactivity of monoclonal ER antibodies with progesterone receptor was observed

Biological conversion assay using Clostridium phytofermentans to estimate plant feedstock quality.

Science.gov (United States)

Lee, Scott J; Warnick, Thomas A; Pattathil, Sivakumar; Alvelo-Maurosa, Jesús G; Serapiglia, Michelle J; McCormick, Heather; Brown, Virginia; Young, Naomi F; Schnell, Danny J; Smart, Lawrence B; Hahn, Michael G; Pedersen, Jeffrey F; Leschine, Susan B; Hazen, Samuel P

2012-02-08

There is currently considerable interest in developing renewable sources of energy. One strategy is the biological conversion of plant biomass to liquid transportation fuel. Several technical hurdles impinge upon the economic feasibility of this strategy, including the development of energy crops amenable to facile deconstruction. Reliable assays to characterize feedstock quality are needed to measure the effects of pre-treatment and processing and of the plant and microbial genetic diversity that influence bioconversion efficiency. We used the anaerobic bacterium Clostridium phytofermentans to develop a robust assay for biomass digestibility and conversion to biofuels. The assay utilizes the ability of the microbe to convert biomass directly into ethanol with little or no pre-treatment. Plant samples were added to an anaerobic minimal medium and inoculated with C. phytofermentans, incubated for 3 days, after which the culture supernatant was analyzed for ethanol concentration. The assay detected significant differences in the supernatant ethanol from wild-type sorghum compared with brown midrib sorghum mutants previously shown to be highly digestible. Compositional analysis of the biomass before and after inoculation suggested that differences in xylan metabolism were partly responsible for the differences in ethanol yields. Additionally, we characterized the natural genetic variation for conversion efficiency in Brachypodium distachyon and shrub willow (Salix spp.). Our results agree with those from previous studies of lignin mutants using enzymatic saccharification-based approaches. However, the use of C. phytofermentans takes into consideration specific organismal interactions, which will be crucial for simultaneous saccharification fermentation or consolidated bioprocessing. The ability to detect such phenotypic variation facilitates the genetic analysis of mechanisms underlying plant feedstock quality.

Biological conversion assay using Clostridium phytofermentans to estimate plant feedstock quality

Directory of Open Access Journals (Sweden)

Lee Scott J

2012-02-01

Full Text Available Abstract Background There is currently considerable interest in developing renewable sources of energy. One strategy is the biological conversion of plant biomass to liquid transportation fuel. Several technical hurdles impinge upon the economic feasibility of this strategy, including the development of energy crops amenable to facile deconstruction. Reliable assays to characterize feedstock quality are needed to measure the effects of pre-treatment and processing and of the plant and microbial genetic diversity that influence bioconversion efficiency. Results We used the anaerobic bacterium Clostridium phytofermentans to develop a robust assay for biomass digestibility and conversion to biofuels. The assay utilizes the ability of the microbe to convert biomass directly into ethanol with little or no pre-treatment. Plant samples were added to an anaerobic minimal medium and inoculated with C. phytofermentans, incubated for 3 days, after which the culture supernatant was analyzed for ethanol concentration. The assay detected significant differences in the supernatant ethanol from wild-type sorghum compared with brown midrib sorghum mutants previously shown to be highly digestible. Compositional analysis of the biomass before and after inoculation suggested that differences in xylan metabolism were partly responsible for the differences in ethanol yields. Additionally, we characterized the natural genetic variation for conversion efficiency in Brachypodium distachyon and shrub willow (Salix spp.. Conclusion Our results agree with those from previous studies of lignin mutants using enzymatic saccharification-based approaches. However, the use of C. phytofermentans takes into consideration specific organismal interactions, which will be crucial for simultaneous saccharification fermentation or consolidated bioprocessing. The ability to detect such phenotypic variation facilitates the genetic analysis of mechanisms underlying plant feedstock quality.

Detection of Hypoxia in Human Brain Tumor Xenografts Using a Modified Comet Assay

Directory of Open Access Journals (Sweden)

Jingli Wang

2003-07-01

Full Text Available We used the standard comet assay successfully to generate in vitro dose-response curves under oxic and hypoxic conditions. We then made mixtures of cells that had been irradiated with 3 and 9 Gy of X-rays to simulate two subpopulations in a tumor, but efforts to accurately detect and quantify the subpopulations using the standard comet assay were unsuccessful. Therefore, we investigated a modified comet assay to determine whether it could be used for measuring hypoxia in our model systems. U251 MG cells were grown as subcutaneous tumors in athymic mice; U251 MG and U87 MG cells were grown as intracerebral (i.c. tumors in athymic rats. Animals were injected with RSU 1069, irradiated, and euthanized. Tumors and normal brains were removed, and the cells were analyzed using a modified comet assay. Differences in comet tail moment distributions between tumor and contralateral normal brain, using tail moments at either the 25th or 50th percentile in each distribution, were taken as measures of the degree of tumor hypoxia. For U251 MG tumors, there was a positive relationship between tumor size and the degree of hypoxia, whereas preliminary data from U87 MG i.c. tumors showed less hypoxia and no apparent relationship between tumor size and hypoxia.

The influence of condensed tannin structure on rate of microbial mineralization and reactivity to chemical assays.

Science.gov (United States)

Norris, Charlotte E; Preston, Caroline M; Hogg, Karen E; Titus, Brian D

2011-03-01

We examined how tannin structure influences reactivity in tannin assays and carbon and nitrogen mineralization. Condensed tannins from the foliage of ten tree and shrub species and from pecan shells (Carya illinoensis) had different proportions of: (a) epicatechin (cis) and catechin (trans) isomers, (b) procyanidin (PC) and prodelphinidin (PD) monomers, and (c) different chain lengths. The response of each tannin to several widely used tannin assays was determined. Although there was some variation in response to proanthocyanidin (butanol/HCl) and Folin Ciocalteu assays, we did not deduce any predictable relationship between tannin structure and response to either assay. There was little variation in protein precipitation among the different tannins. To assess biological activity, six of the tannins were incubated with forest humus for 22 days. We determined that, while PC-based tannins remained at least partly extractable for the duration of the incubation, tannins with a high proportion of PD subunits rapidly became unextractable from soil. There was a positive correlation between net nitrogen mineralization and cis chemical structure. Carbon mineralization was enhanced initially by the addition of tannins to humus, but after 22 days, a negative correlation between the proportion of cis subunits and respiration was determined. Overall, we were not able to demonstrate consistent effects of structure on either microbial mineralization or reactivity to chemical assays; such relationships remain elusive.

Embolus location affects the sensitivity of a rapid quantitative D-dimer assay in the diagnosis of pulmonary embolism

NARCIS (Netherlands)

de Monyé, Wouter; Sanson, Bernd-Jan; Mac Gillavry, Melvin R.; Pattynama, Peter M. T.; Büller, Harry R.; van den Berg-Huysmans, Annette A.; Huisman, Menno V.

2002-01-01

D-dimer blood tests have been suggested to rule out pulmonary embolism. Despite evidence of the safety of withholding anticoagulant treatment in patients with suspected pulmonary embolism and a normal D-dimer assay result, clinicians remain reluctant to use a D-dimer assay as a sole diagnostic test.

Development and characterization of a high density SNP genotyping assay for cattle.

Directory of Open Access Journals (Sweden)

Lakshmi K Matukumalli

Full Text Available The success of genome-wide association (GWA studies for the detection of sequence variation affecting complex traits in human has spurred interest in the use of large-scale high-density single nucleotide polymorphism (SNP genotyping for the identification of quantitative trait loci (QTL and for marker-assisted selection in model and agricultural species. A cost-effective and efficient approach for the development of a custom genotyping assay interrogating 54,001 SNP loci to support GWA applications in cattle is described. A novel algorithm for achieving a compressed inter-marker interval distribution proved remarkably successful, with median interval of 37 kb and maximum predicted gap of <350 kb. The assay was tested on a panel of 576 animals from 21 cattle breeds and six outgroup species and revealed that from 39,765 to 46,492 SNP are polymorphic within individual breeds (average minor allele frequency (MAF ranging from 0.24 to 0.27. The assay also identified 79 putative copy number variants in cattle. Utility for GWA was demonstrated by localizing known variation for coat color and the presence/absence of horns to their correct genomic locations. The combination of SNP selection and the novel spacing algorithm allows an efficient approach for the development of high-density genotyping platforms in species having full or even moderate quality draft sequence. Aspects of the approach can be exploited in species which lack an available genome sequence. The BovineSNP50 assay described here is commercially available from Illumina and provides a robust platform for mapping disease genes and QTL in cattle.

Clinical experience with a radioreceptor assay for TSH-binding inhibiting immunoglobulins (TBII)

International Nuclear Information System (INIS)

Heberling, H.J.; Bierwolf, B.; Lohmann, D.

1988-01-01

The aim was evaluate the clinical value of a commercial kit for determination of TSH-binding inhibiting immunoglobulin (TBII). 47 of 50 patients with untreated hyperthyroid Graves' disease were TBII positive (sensitivity 94%). TBII was in the normal range in all normal volunteers and in patients with simple goiter, thyroid cancer and in most cases of nonimmunogenic hyperthyreoidism (19 of 22). After 12 months antithyroid drug therapy with methimazole of 21 patients the prevalence of positive TBII findings was 28%. In contrast to this, 50 percent of the patients had increased microsomal antibodies at the end of therapy. The determination of TBII by TRAK assay proved to be a sensitive, specific and practical method. The assay can be used to differentiate between hyperthyreoidism of autoimmune or nonimmunogenic origin. Even so this method seems to be helpful for the follow-up during medical treatment of patients with Graves' disease. The results indicate that persistence of increased TBII levels are markers of active Graves' disease and suggest that in this situation ablative measures should be performed. Normalization of TBII on the end of a longstanding antithyroid therapy does not exclude the possibility of relapse in the further course. (author)

A non-isotopic assay uses bromouridine and RNA synthesis to detect DNA damage responses.

Science.gov (United States)

Hasegawa, Mayu; Iwai, Shigenori; Kuraoka, Isao

2010-06-17

Individuals with inherited xeroderma pigmentosum (XP) disorder and Cockayne syndrome (CS) are deficient in nucleotide excision repair and experience hypersensitivity to sunlight. Although there are several diagnostic assays for these disorders, the recovery of RNA synthesis (RRS) assay that can discriminate between XP cells and CS cells is very laborious. Here, we report on a novel non-radioisotope RRS assay that uses bromouridine (a uridine analog) as an alternative to (3)H-uridine. This assay can easily detect RNA polymerase I transcription in nucleoli and RNA polymerase II transcription in nuclei. The non-RI RSS assay also can rapidly detect normal RRS activity in HeLa cells. Thus, this assay is useful as a novel and easy technique for CS diagnosis. Because RRS is thought to be related to transcription-coupled DNA repair, which is triggered by the blockage of transcriptional machinery by DNA lesions, this assay may be of use for analysis of DNA repair, transcription, and/or genetic toxicity. Copyright 2010 Elsevier B.V. All rights reserved.

Factors affecting a cyanogen bromide-based assay of thiamin.

Science.gov (United States)

Wyatt, D T; Lee, M; Hillman, R E

1989-11-01

We analyzed extensively a modified thiochrome method for thiamin analysis. Acid phosphatase (EC 3.1.3.2) from potato was superior to either alpha-amylase or acid phosphatase from wheat germ as a dephosphorylating agent. Timing of cyanogen bromide exposure was important, but the assay had good precision and accuracy. The standard curve was linear from 10 to 3000 nmol/L. The within-run and between-run coefficients of variation for total thiamin in whole blood were 3.6% and 7.4%, respectively. Analytical recoveries for low, intermediate, and high additions of thiamin to whole blood were 93-109%. Sample yield was increased by 41% (+/- 29% SD) with pre-assay freezing. Samples were stable for two days at room temperature, for seven days when refrigerated, and for two years when frozen. Previously unreported interference was seen with penicillin derivatives, and with several commonly used diuretic and antiepileptic medications. This assay may be suitable for population screening; 200 samples could be analyzed weekly at a cost of +0.20 per sample.

Dynamic knee alignment and collateral knee laxity and its variations in normal humans

Directory of Open Access Journals (Sweden)

Kamal eDeep

2015-11-01

Full Text Available Alignment of normal, arthritic and replaced human knees is a much debated subject as is the collateral ligamentous laxity. Traditional quantitative values have been challenged. Methods used to measure these are also not without flaws. Authors review the recent literature and a novel method of measurement of these values has been included. This method includes use of computer navigation technique in clinic setting for assessment of the normal or affected knee before the surgery. Computer navigation has been known for achievement of alignment accuracy during knee surgery. Now its use in clinic setting has added to the inventory of measurement methods. Authors dispel the common myth of straight mechanical axis in normal knees and also look at quantification of amount of collateral knee laxity. Based on the scientific studies it has been shown that the mean alignment is in varus in normal knees. It changes from lying non weight bearing position to standing weight bearing position in both coronal and the sagittal planes. It also varies with gender and race. The collateral laxity is also different for males and females. Further studies are needed to define the ideal alignment and collateral laxity which the surgeon should aim for individual knees.

Normal variants of the intracranial circulation demonstrated by MR angiography at 3 T

International Nuclear Information System (INIS)

Parmar, H.; Sitoh, Y.Y.; Hui, F.

2005-01-01

Magnetic resonance angiography (MRA) at 3 T offers increased signal to noise ratio with better background suppression, leading to exquisite depiction of the intracranial circulation. We present a pictorial review of the normal variations and anomalies of the intracranial circulation detected on MRA performed on a high field 3 T clinical scanner using parallel imaging techniques. The salient imaging features of these anomalies and normal variations are discussed with relevance to clinical practice

Measurement of plasma histamine: description of an improved method and normal values

International Nuclear Information System (INIS)

Dyer, J.; Warren, K.; Merlin, S.; Metcalfe, D.D.; Kaliner, M.

1982-01-01

The single isotopic-enzymatic assay of histamine was modified to increase its sensitivity and to facilitate measurement of plasma histamine levels. The modification involved extracting 3 H-1-methylhistamine (generated by the enzyme N-methyltransferase acting on histamine in the presence of S-[methyl- 3 H]-adenosyl-L-methionine) into chloroform and isolating the 3 H-1-methylhistamine by thin-layer chromatography (TLC). The TLC was developed in acetone:ammonium hydroxide (95:10), and the methylhistamine spot (Rf . 0.50) was identified with an o-phthalaldehyde spray, scraped from the plate, and assayed in a scintillation counter. The assay in plasma demonstrated a linear relationship from 200 to 5000 pg histamine/ml. Plasma always had higher readings than buffer, and dialysis of plasma returned these values to the same level as buffer, suggesting that the baseline elevations might be attributable to histamine. However, all histamine standard curves were run in dialyzed plasma to negate any additional influences plasma might exert on the assay. The arithmetic mean (+/- SEM) in normal plasma histamine was 318.4 +/- 25 pg/ml (n . 51), and the geometric mean was 280 +/- 35 pg/ml. Plasma histamine was significantly elevated by infusion of histamine at 0.05 to 1.0 micrograms/kg/min or by cold immersion of the hand of a cold-urticaria patient. Therefore this modified isotopic-enzymatic assay of histamine is extremely sensitive, capable of measuring fluctuations in plasma histamine levels within the normal range, and potentially useful in analysis of the role histamine plays in human physiology

The effect of different methods and image analyzers on the results of the in vivo comet assay.

Science.gov (United States)

Kyoya, Takahiro; Iwamoto, Rika; Shimanura, Yuko; Terada, Megumi; Masuda, Shuichi

2018-01-01

The in vivo comet assay is a widely used genotoxicity test that can detect DNA damage in a range of organs. It is included in the Organisation for Economic Co-operation and Development Guidelines for the Testing of Chemicals. However, various protocols are still used for this assay, and several different image analyzers are used routinely to evaluate the results. Here, we verified a protocol that largely contributes to the equivalence of results, and we assessed the effect on the results when slides made from the same sample were analyzed using two different image analyzers (Comet Assay IV vs Comet Analyzer). Standardizing the agarose concentrations and DNA unwinding and electrophoresis times had a large impact on the equivalence of the results between the different methods used for the in vivo comet assay. In addition, there was some variation in the sensitivity of the two different image analyzers tested; however this variation was considered to be minor and became negligible when the test conditions were standardized between the two different methods. By standardizing the concentrations of low melting agarose and DNA unwinding and electrophoresis times between both methods used in the current study, the sensitivity to detect the genotoxicity of a positive control substance in the in vivo comet assay became generally comparable, independently of the image analyzer used. However, there may still be the possibility that other conditions, except for the three described here, could affect the reproducibility of the in vivo comet assay.

The evaluation of domestic immunoradiometric assay kit for alpha-fetoprotein

Energy Technology Data Exchange (ETDEWEB)

Won, Kyoung Sook; Ryu, Jin Sook; Moon, Dae Hyuk; Lee, Hee Kyung [Ulsan Univ. College of Medicine, Seoul (Korea, Republic of)

2000-08-01

Although {alpha}-fetoprotein is one of the most commonly used tumor markers in Korea, most of the radioimmunoassay kits for {alpha}-fetoprotein have been imported from foreign countries. The purpose of this study was to evaluate the performance of a recently developed domestic immunoradiometric kit for {alpha}-fetoprotein (Riakey AFP IRMA CT{sup R}, Sin-Jin Medics, Seoul, Korea). We evaluated intra-and inter-assay precision, recovery rate, parallelism, and sensitivity of serum {alpha}-fetoprotein measurement using Riakey AFP IRMA CT{sup R} kit. The values of {alpha}-fetoprotein measured by Riakey AFP IRMA CT{sup R} kit were compared with those measured by two foreign commercial kits ({alpha}-fetoproteina of Radim and {alpha}-feto.riabead of Abbott). Intra-assay coefficients of variation on three different levels were 5.3% for 18.9 ng/ml, 3.4% for 133 ng/ml and 1.6% for 330 ng/ml. Inter-assay coefficients of variation were 9.7% for 20.9 ng/ml, 3.2% for 137 ng/ml and 4.1% for 330 ng/ml respectively. Recovery rate tests on all three different levels showed within 100{+-}10%. Parallelism was also good and the sensitivity was 0.63 ng/ml. There was strong correlation between the measurement of {alpha}-fetoprotein by Riakey AFP IRMA CT{sup R} and that by two foreign commercial kits(r=3D0.98). The first Korean domestic immunoradiometric kit for {alpha}-fetoprotein, Riakey AFP IRMA CT{sup R}, performed well for clinical use.

Multi-centre evaluation of recent troponin assays for the diagnosis of NSTEMI

Directory of Open Access Journals (Sweden)

Camille Chenevier-Gobeaux

2018-07-01

Full Text Available Objectives: We aimed to compare the use of nine different cardiac troponin (cTn assays (2 cTnT and 7 cTnI for the diagnosis of NSTEMI in a single multi-centre population. Design and methods: One hundred and fifty-eight patients were included (mean age 60 years, SD 17 years, including 23 patients (14% with NSTEMI. Results: The analytical comparison highlighted a large heterogeneity of cTn assays, as reflected by percentages of patients with detectable cTn, correlation coefficients, Passing-Bablok comparisons and concordance coefficients. Correlations within cTnI assays were good and correlation within cTnT assays was excellent. Diagnostic performances demonstrated that each cTn assay has specific threshold values. Furthermore, some assays (HS-cTnI and T, cTnI-Pathfast and cTnI-Centaur indicated high sensitivity and negative predictive value using the limit of detection (LoD diagnostic strategy. For the latter assays, a significant increase in specificity was found when using the 99th percentile or the H0-H3 strategies, in comparison to the LoD strategy. When applying the European Society of Cardiology H0-H3 algorithm, comparable diagnostic performances were obtained. Conclusion: All 9 cTn assays indicated overall good diagnostic performances for the diagnosis of NSTEMI in emergency departments when the recommended algorithm based on the variation of cTn value between two measurements at admission and 3 h later was used. Keywords: Cardiac troponin, High-sensitivity assay, Chest pain, Emergency department, NSTEMI, Analytical evaluation

Skull-base foramina of the middle cranial fossa : assessment of normal variation with high-resolution CT

International Nuclear Information System (INIS)

Kim, Hyae Young; Chung, Eun Chul; Suh, Jeong Soo; Choi, Hye Young; Ko, Eun Joo; Lee, Myung Sook

1997-01-01

To recognize foraminal variants of the foraminae of the skull base in the middle cranial fossa, and to thus understand and distinguish normal and potentially abnormal structures. We analysed 163 patients without intracranial disease who had undergone CT scanning. These comprised 82 men and 81 women with a mean age of 39 years (range, 4-73 years). HRCT was performed, using a GE 9800 scanner. All CT scans were obtained 6-7 slices at the base of the skull, with 1.5mm collimation at 1.5mm intervals parallel to the infraorbital line. We analysed the foraminae by closesly correlating imaging findings and established anatomic knowledge. In 45 cases (27.6%) the foramen ovale was 5-10mm in diameter and asymmetrical. Deficiency of the medial bony wall including persistent foramen lacerum medius was seen in five cases (3.1%). Confluence of the foramen ovale and the foramen spinosum was seen in 13 cases (8%) and confluence of the foramen ovale and the foramen of Vesalius in 23 (14.1%). Posterolateral groove for the accessory meningeal artery was observed in 36 cases (22%). The foramen spinosum was asymmetrical in 42 cases (25.8%). A small or absent foramen spinosum with a larger ipsilateral foramen ovale was observed in 11 cases (6.7%). Medial bony defect was seen in 16 cases (9.8%). The foramen spinosum was absent in four cases (2.5%). In 74 cases (45.4%), the foramen of Vesalius was absent; it was present unilaterally and bilaterally in 55 (33.7%) and 34 cases (20.9%), respectively. Five cases showed duplicated foramina. Canaliculus innominatus was seen in 14 cases (8.9%) and was present bilaterally in three (1.8%). HRCT clearly delineates bony structure and is well able to display the rich spectrum of anatomic variation found in the base of the skull. The recognition of these normal variants will result in a better understanding of skull base neurovascular anatomy and diminish speculation as to their true nature during the interpretation of CT images

Measuring factor IX activity of nonacog beta pegol with commercially available one-stage clotting and chromogenic assay kits: a two-center study.

Science.gov (United States)

Bowyer, A E; Hillarp, A; Ezban, M; Persson, P; Kitchen, S

2016-07-01

Essentials Validated assays are required to precisely measure factor IX (FIX) activity in FIX products. N9-GP and two other FIX products were assessed in various coagulation assay systems at two sites. Large variations in FIX activity measurements were observed for N9-GP using some assays. One-stage and chromogenic assays accurately measuring FIX activity for N9-GP were identified. Background Measurement of factor IX activity (FIX:C) with activated partial thromboplastin time-based one-stage clotting assays is associated with a large degree of interlaboratory variation in samples containing glycoPEGylated recombinant FIX (rFIX), i.e. nonacog beta pegol (N9-GP). Validation and qualification of specific assays and conditions are necessary for the accurate assessment of FIX:C in samples containing N9-GP. Objectives To assess the accuracy of various one-stage clotting and chromogenic assays for measuring FIX:C in samples containing N9-GP as compared with samples containing rFIX or plasma-derived FIX (pdFIX) across two laboratory sites. Methods FIX:C, in severe hemophilia B plasma spiked with a range of concentrations (from very low, i.e. 0.03 IU mL(-1) , to high, i.e. 0.90 IU mL(-1) ) of N9-GP, rFIX (BeneFIX), and pdFIX (Mononine), was determined at two laboratory sites with 10 commercially available one-stage clotting assays and two chromogenic FIX:C assays. Assays were performed with a plasma calibrator and different analyzers. Results A high degree of variation in FIX:C measurement was observed for one-stage clotting assays for N9-GP as compared with rFIX or pdFIX. Acceptable N9-GP recovery was observed in the low-concentration to high-concentration samples tested with one-stage clotting assays using SynthAFax or DG Synth, or with chromogenic FIX:C assays. Similar patterns of FIX:C measurement were observed at both laboratory sites, with minor differences probably being attributable to the use of different analyzers. Conclusions These results suggest that, of the

Anatomic variations of the cochlea and relations to other temporal bone structures

Energy Technology Data Exchange (ETDEWEB)

Dimopoulos, P.; Muren, C. (Akademiska Sjukhuset, Uppsala (Sweden). Dept. of Diagnostic Radiology Sabbatsberg' s Sjukhus, Stockholm (Sweden). Dept. of Diagnostic Radiology)

1990-09-01

The size and shape of the human cochlea and the normal ranges of variation of its dimensions were evaluated in 95 plastic casts, prepared from temporal bone specimens. The normal range of variation is fairly small, and is not age-dependent. Obvious digression from this range, associated with pertinent clinical symptoms, indicates an abnormality. (orig./MG).

Assaying Cellular Viability Using the Neutral Red Uptake Assay.

Science.gov (United States)

Ates, Gamze; Vanhaecke, Tamara; Rogiers, Vera; Rodrigues, Robim M

2017-01-01

The neutral red uptake assay is a cell viability assay that allows in vitro quantification of xenobiotic-induced cytotoxicity. The assay relies on the ability of living cells to incorporate and bind neutral red, a weak cationic dye, in lysosomes. As such, cytotoxicity is expressed as a concentration-dependent reduction of the uptake of neutral red after exposure to the xenobiotic under investigation. The neutral red uptake assay is mainly used for hazard assessment in in vitro toxicology applications. This method has also been introduced in regulatory recommendations as part of 3T3-NRU-phototoxicity-assay, which was regulatory accepted in all EU member states in 2000 and in the OECD member states in 2004 as a test guideline (TG 432). The present protocol describes the neutral red uptake assay using the human hepatoma cell line HepG2, which is often employed as an alternative in vitro model for human hepatocytes. As an example, the cytotoxicity of acetaminophen and acetyl salicylic acid is assessed.

GC-Content Normalization for RNA-Seq Data

Science.gov (United States)

2011-01-01

Background Transcriptome sequencing (RNA-Seq) has become the assay of choice for high-throughput studies of gene expression. However, as is the case with microarrays, major technology-related artifacts and biases affect the resulting expression measures. Normalization is therefore essential to ensure accurate inference of expression levels and subsequent analyses thereof. Results We focus on biases related to GC-content and demonstrate the existence of strong sample-specific GC-content effects on RNA-Seq read counts, which can substantially bias differential expression analysis. We propose three simple within-lane gene-level GC-content normalization approaches and assess their performance on two different RNA-Seq datasets, involving different species and experimental designs. Our methods are compared to state-of-the-art normalization procedures in terms of bias and mean squared error for expression fold-change estimation and in terms of Type I error and p-value distributions for tests of differential expression. The exploratory data analysis and normalization methods proposed in this article are implemented in the open-source Bioconductor R package EDASeq. Conclusions Our within-lane normalization procedures, followed by between-lane normalization, reduce GC-content bias and lead to more accurate estimates of expression fold-changes and tests of differential expression. Such results are crucial for the biological interpretation of RNA-Seq experiments, where downstream analyses can be sensitive to the supplied lists of genes. PMID:22177264

Radiobiological predictors of tumor and acute normal tissue response in radiotherapy for head and neck cancers

International Nuclear Information System (INIS)

Maciejewski, B.; Skladowski, K.; Zajusz, A.

1991-01-01

The importance of measurements of the potential doubling time (T pot. ) and of the survival fraction at 2.0 Gy (SF 2 ), and a method modifying acute radiation response of normal oral mucosa are discussed. Tumor clonogen repopulation accelerates around day 28 of the treatment, and the rate of repopulation is not constant but continuously increases from about 0.3 Gy/day to 1.0-1.3 Gy/day between day 28 and 65 of the treatment. This may suggest that T pot. values decrease correspondingly. The relevance of prior-to-treatment T pot. measurements to clinical situations is discussed. The SF 2 value reflects the intrinsic radiosensitivity of human tumors. The SF 2 values are expected to be valuable as predictors for tumor response to irradiation. Variations in the SF 2 values depending on tumor characteristics and assay methods are discussed in relation to the dose response and tumor cure probability. The effect of modifying the repopulation rate in the oral mucosa by stimulation with a 2% silver nitrate solution is discussed. Although these prognosticators are different in their nature, they might provide a rational basis for selecting patients into optimal irradiation treatment and might allow to modify the radiation response of dose-limiting normal tissues. (author). 5 figs., 1 tab., 28 refs

Molecular analysis of quality protein (QPM) and normal maize ...

African Journals Online (AJOL)

Jane

2011-10-24

Oct 24, 2011 ... genetic variation among QPM and normal maize varieties is important for an efficient selection and .... olymerase chain reaction (PCR) amplifications of RAPD and ISSR ..... Genetic characterization of Malawian cowpea.

Quantitative proteome profiling of normal human circulating microparticles

DEFF Research Database (Denmark)

Østergaard, Ole; Nielsen, Christoffer T; Iversen, Line V

2012-01-01

Circulating microparticles (MPs) are produced as part of normal physiology. Their numbers, origin, and composition change in pathology. Despite this, the normal MP proteome has not yet been characterized with standardized high-resolution methods. We here quantitatively profile the normal MP...... proteome using nano-LC-MS/MS on an LTQ-Orbitrap with optimized sample collection, preparation, and analysis of 12 different normal samples. Analytical and procedural variation were estimated in triply processed samples analyzed in triplicate from two different donors. Label-free quantitation was validated...... by the correlation of cytoskeletal protein intensities with MP numbers obtained by flow cytometry. Finally, the validity of using pooled samples was evaluated using overlap protein identification numbers and multivariate data analysis. Using conservative parameters, 536 different unique proteins were quantitated...

Stationary and protable instruments for assay of HEU [highly enriched uranium] solids holdup

International Nuclear Information System (INIS)

Russo, P.A.; Sprinkle, J.K. Jr.; Stephens, M.M.; Brumfield, T.L.; Gunn, C.S.; Watson, D.R.

1987-01-01

Two NaI(Tl)-based instruments, one stationary and one portable, designed for automated assay of highly enriched uranium (HEU) solids holdup, are being evaluated at the scrap recovery facility of the Oak Ridge Y-12 Plant. The stationary instrument, a continuous monitor of HEU within the filters of the chip burner exhaust system, measures the HEU deposits that accumulate erratically and rapidly during chip burner operation. The portable system was built to assay HEU in over 100 m of elevated piping used to transfer UO 3 , UO 2 , and UF 4 powder to, from, and between the fluid bed conversion furnances and the powder storage hoods. Both instruments use two detector heads. Both provide immediate automatic readout of accumulated HEU mass. The 186-keV 235 U gamma ray is the assay signature, and the 60-keV gamma ray from an 241 Am source attached to each detector is used to normalize the 186-keV rate. The measurement geometries were selected for compatibility with simple calibration models. The assay calibrations were calculated from these models and were verified and normalized with measurements of HEU standards built to match geometries of uniform accumulations on the surfaces of the process equipment. This instrumentation effort demonstrates that simple calibration models can often be applied to unique measurement geometries, minimizing the otherwise unreasonable requirements for calibration standards and allowing extension of the measurements to other process locations

Lithium control during normal operation

International Nuclear Information System (INIS)

Suryanarayan, S.; Jain, D.

2010-01-01

Periodic increases in lithium (Li) concentrations in the primary heat transport (PHT) system during normal operation are a generic problem at CANDU® stations. Lithiated mixed bed ion exchange resins are used at stations for pH control in the PHT system. Typically tight chemistry controls including Li concentrations are maintained in the PHT water. The reason for the Li increases during normal operation at CANDU stations such as Pickering was not fully understood. In order to address this issue a two pronged approach was employed. Firstly, PNGS-A data and information from other available sources was reviewed in an effort to identify possible factors that may contribute to the observed Li variations. Secondly, experimental studies were carried out to assess the importance of these factors in order to establish reasons for Li increases during normal operation. Based on the results of these studies, plausible mechanisms/reasons for Li increases have been identified and recommendations made for proactive control of Li concentrations in the PHT system. (author)

Radioimmunoassay and heat denaturation enzyme assay for the detection of Tay-Sachs heterozygotes during pregnancy

International Nuclear Information System (INIS)

Nguyen, C.; Gold, R.J.M.; Mahuran, D.; Lowden, J.A.

1981-01-01

Tay-Sachs disease results from a loss of activity of hexosaminidase A (HEX A) in body tissues and fluids. Heterozygotes for the disease are usually identified by their relatively low ratio of heat-labile HEX A to total hexosaminidase. During pregnancy an intermediate isoenzyme (HEX I) increases in activity in serum and obscures the heterozygote status. HEX I does not increase in leucocytes, tears and other body tissues but because of technical difficulties in these assays the authors examined the feasibility of using a radioimmunoassay for HEX A. By univariate analysis, the heat denaturation assay gave a lower cost of misclassification for non-pregnant normals while RIA did so for pregnant normals. A combination of both tests led to reduced cost of misclassification compared to either alone. Bayesian analysis of bivariate gaussian density functions for heat denaturation and for radioimmunoassays of HEX isoenzymes was employed to calculate misclassification frequencies. Among the parameters examined, HEX A measured by RIA and % HEX A by heat-denaturation assay were the two having the best discriminatory power. (Auth.)

European Multicenter Study on Analytical Performance of Veris HIV-1 Assay.

Science.gov (United States)

Braun, Patrick; Delgado, Rafael; Drago, Monica; Fanti, Diana; Fleury, Hervé; Hofmann, Jörg; Izopet, Jacques; Kalus, Ulrich; Lombardi, Alessandra; Marcos, Maria Angeles; Mileto, Davide; Sauné, Karine; O'Shea, Siobhan; Pérez-Rivilla, Alfredo; Ramble, John; Trimoulet, Pascale; Vila, Jordi; Whittaker, Duncan; Artus, Alain; Rhodes, Daniel W

2017-07-01

The analytical performance of the Veris HIV-1 assay for use on the new, fully automated Beckman Coulter DxN Veris molecular diagnostics system was evaluated at 10 European virology laboratories. The precision, analytical sensitivity, performance with negative samples, linearity, and performance with HIV-1 groups/subtypes were evaluated. The precision for the 1-ml assay showed a standard deviation (SD) of 0.14 log 10 copies/ml or less and a coefficient of variation (CV) of ≤6.1% for each level tested. The 0.175-ml assay showed an SD of 0.17 log 10 copies/ml or less and a CV of ≤5.2% for each level tested. The analytical sensitivities determined by probit analysis were 19.3 copies/ml for the 1-ml assay and 126 copies/ml for the 0.175-ml assay. The performance with 1,357 negative samples demonstrated 99.2% with not detected results. Linearity using patient samples was shown from 1.54 to 6.93 log 10 copies/ml. The assay performed well, detecting and showing linearity with all HIV-1 genotypes tested. The Veris HIV-1 assay demonstrated analytical performance comparable to that of currently marketed HIV-1 assays. (DxN Veris products are Conformité Européenne [CE]-marked in vitro diagnostic products. The DxN Veris product line has not been submitted to the U.S. FDA and is not available in the U.S. market. The DxN Veris molecular diagnostics system is also known as the Veris MDx molecular diagnostics system and the Veris MDx system.). Copyright © 2017 American Society for Microbiology.

Normalization reduces intersubject variability in cervical vestibular evoked myogenic potentials.

Science.gov (United States)

van Tilburg, Mark J; Herrmann, Barbara S; Guinan, John J; Rauch, Steven D

2014-09-01

Cervical vestibular evoked myogenic potentials are used to assess saccular and inferior vestibular nerve function. Normalization of the VEMP waveform has been proposed to reduce the variability in vestibular evoked myogenic potentials by correcting for muscle activation. In this study, we test the hypothesis that normalization of the raw cervical VEMP waveform causes a significant decrease in the intersubject variability. Prospective cohort study. Large specialty hospital, department of otolaryngology. Twenty healthy subjects were used in this study. All subjects underwent cervical vestibular evoked myogenic potential testing using short tone bursts at 250, 500, 750, and 1,000 Hz. Both intersubject and intrasubject variability was assessed. Variability between raw and normalized peak-to-peak amplitudes was compared using the coefficient of variation. Intrasubject variability was assessed using the intraclass correlation coefficient and interaural asymmetry ratio. cVEMPs were present in most ears. Highest peak-to-peak amplitudes were recorded at 750 Hz. Normalization did not alter cVEMP tuning characteristics. Normalization of the cVEMP response caused a significant reduction in intersubject variability of the peak-to-peak amplitude. No significant change was seen in the intrasubject variability. Normalization significantly reduces cVEMP intersubject variability in healthy subjects without altering cVEMP characteristics. By reducing cVEMP amplitude variation due to nonsaccular, muscle-related factors, cVEMP normalization is expected to improve the ability to distinguish between healthy and pathologic responses in the clinical application of cVEMP testing.

Regulation mechanisms of pituitary-thyroid axis in normal subjects and patients with Graves' disease

International Nuclear Information System (INIS)

Takagi, Shinko; Yamauchi, Kazuyuki; Mori, Yuichi

1986-01-01

The regulatory mechanism of the pituitary-thyroid axis in normal subjects and patients with Graves' disease was investigated using a highly sensitive TSH assay based on the immunoradiometric assay. All of the normal subjects had detectable TSH values within the range 0.35 to 6.0 μU/ml. No negative correlations between TSH and free thyroid hormones existed in normal subjects. Patients with thyroid carcinoma who seemed to have normal pituitary-thyroid function showed a rapid increase of TSH after total thyroidectomy. On the other hand, while untreated patients with Graves' disease all had undetectable TSH values, these patients took 1 to 3.5 months longer to normalize their TSH values than to normalize free thyroid hormones on antithyroid drug therapy. During the recovery phase by the treatment with decrease of antithyroid drug or supplement of T 4 from iatrogenic hypothyroid state after treatment for Graves' disease and thyroid carcinoma, normalization of TSH levels was delayed than that of free thyroid hormones. Patients with Graves' disease in remission showed an extremely positive correlation between basal and peak TSH levels in TRH test, and a negative correlation between basal TSH and FT 4 . In conclusion, an individual patient may have a different set point concerning the regulatory mechanism of the pituitary-thyroid axis, and the persistence of the hyperthyroid state would seem to have caused some reversible dysfunction of the pituitary gland. (author)

Variation in aerodynamic coefficients with altitude

Science.gov (United States)

Shahid, Faiza; Hussain, Mukkarum; Baig, Mirza Mehmood; Haq, Ihtram ul

Precise aerodynamics performance prediction plays key role for a flying vehicle to get its mission completed within desired accuracy. Aerodynamic coefficients for same Mach number can be different at different altitude due to difference in Reynolds number. Prediction of these aerodynamics coefficients can be made through experiments, analytical solution or Computational Fluid Dynamics (CFD). Advancements in computational power have generated the concept of using CFD as a virtual Wind Tunnel (WT), hence aerodynamic performance prediction in present study is based upon CFD (numerical test rig). Simulations at different altitudes for a range of Mach numbers with zero angle of attack are performed to predict axial force coefficient behavior with altitude (Reynolds number). Similar simulations for a fixed Mach number '3' and a range of angle of attacks are also carried out to envisage the variation in normal force and pitching moment coefficients with altitude (Reynolds number). Results clearly depict that the axial force coefficient is a function of altitude (Reynolds number) and increase as altitude increases, especially for subsonic region. Variation in axial force coefficient with altitude (Reynolds number) slightly increases for larger values of angle of attacks. Normal force and pitching moment coefficients do not depend on altitude (Reynolds number) at smaller values of angle of attacks but show slight decrease as altitude increases. Present study suggests that variation of normal force and pitching moment coefficients with altitude can be neglected but the variation of axial force coefficient with altitude should be considered for vehicle fly in dense atmosphere. It is recommended to continue this study to more complex configurations for various Mach numbers with side slip and real gas effects.

Evaluation of a competitive enzyme-linked immunosorbent assay for measurements of soluble HLA-G protein

DEFF Research Database (Denmark)

Rasmussen, M; Dahl, M; Buus, S

2014-01-01

. We report a novel method, a competitive immunoassay, for measuring HLA-G5/sHLA-G1 in biological fluids. The sHLA-G immunoassay is based upon a competitive enzyme-linked immunosorbent assay (ELISA) principle. It includes a recombinant sHLA-G1 protein in complex with β2-microglobulin and a peptide...... as a standard, biotinylated recombinant sHLA-G1 as an indicator, and the MEM-G/9 anti-HLA-G monoclonal antibody (mAb) as the capture antibody. The specificity and sensitivity of the assay were evaluated. Testing with different recombinant HLA class I proteins and different anti-HLA class I mAbs showed....../ml. An intra-assay coefficient of variation (CV) of 15.5% at 88 ng/ml and an inter-assay CV of 23.1% at 39 ng/ml were determined. An assay based on the competitive sHLA-G ELISA may be important for measurements of sHLA-G proteins in several conditions: assisted reproduction, organ transplantation, cancer...

New fluorimetric assay of horseradish peroxidase using sesamol as substrate and its application to EIA.

Science.gov (United States)

Arakawa, Hidetoshi; Nakabayashi, Shigeo; Ohno, Ken-Ichi; Maeda, Masako

2012-04-01

Horseradish peroxidase (HRP) is generally used as a label enzyme in enzyme immunoassay (EIA). The procedure used for HRP detection in EIA is critical for sensitivity and precision. This paper describes a novel fluorimetric assay for horseradish peroxidase (HRP) using sesamol as substrate. The principle of the assay is as follow: sesamol (3,4-methylenedioxy phenol) is reacted enzymatically in the presence of hydrogen peroxide to produce dimeric sesamol. The dimer is fluorescent and can be detected sensitively at ex. 347 nm, em. 427 nm. The measurable range of HRP was 1.0×10 -18 to 1.0×10 -15  mol/assay, with a detection limit of 1.0×10 -18  mol/assay. The coefficient of variation (CV, n =8) was examined at each point on the standard curve, with a mean CV percentage of 3.8%. This assay system was applied to thyroid stimulating hormone (TSH) EIA using HRP as the label enzyme.

Matrix effects of TRU [transuranic] assays using the SWEPP PAN assay system

International Nuclear Information System (INIS)

Smith, J.R.

1990-08-01

The Drum Assay System (DAS) at the Stored Waste Experimental Pilot Plant (SWEPP) is a second-generation active-passive neutron assay system. It has been used to assay over 5000 208-liter drums of transuranic waste from the Rocky Flats Plant (RFP). Data from these assays have been examined and compared with the assays performed at Rocky Flats, mainly utilize counting of 239 Pu gamma rays. For the most part the passive assays are in very good agreement with the Rocky Flats assays. The active assays are strongly correlated with the results of the other two methods, but require matrix-dependent correction factors beyond those provided by the system itself. A set of matrix-dependent correction factors has been developed from the study of the assay results. 3 refs., 4 figs., 3 tabs

Study of genetic variation at the level of DNA between normal and sterilized potato tuber moth males (phthorimaea operculella, zeller)

International Nuclear Information System (INIS)

Ammouneh, H.; Makee, H.; Idris, E.

2009-06-01

The main objective of current study was to determine the genetic variation at the level of DNA between the normal and sterilized potato tuber moth males. The required mating experiments were carried out to obtain partially sterilized males at 150 Gy and their offspring. Some biological factors of these males were estimated and compared to their unirradiated siblings. To acquire good quality and quantity of DNA for the AFLP technique, several methods were undertaken to isolate DNA of potato tuber moth male from different developmental stages especially from adult stage. However, a method called Modified M5 was used. By Modified M5, which required phenol for the isolation of DNA, in some samples 8 to 12 μg were obtained from one insect with 95-100% purity. In our study, AFLP technique was used to analyze the DNA samples of irradiated and unirradiated males from required mating. The result analysis showed that there was a clear genetic variability between examined individuals. However, the relationship between unirradiated F1 and F2 males was stronger than that between irradiated males. Thus, our result demonstrates that the AFLP could be efficiently utilized for studying genetic variation between insect species or between individuals of the same line which have biological differences induced by several factors such as irradiation. Moreover, this technique could enhance the effectiveness of sterile insect technique by using the AFLP in the monitoring system of released insects. (author)

Study Of Genetic Variation At The Level Of DNA Between Normal And Steriled Potato Tuber Moth Males (Phthorimaea operculella, Zeller)

International Nuclear Information System (INIS)

Ammouneh, H.; Makee, H.; Idris, E.

2010-01-01

The main objective of current study was to determine the genetic variation at the level of DNA between the normal and sterilized potato tuber moth males. The required mating experiments were carried out to obtain partially sterilize males at 150 Gy and their offspring. Some biological factors of these males were estimated and compared to their unirradiated siblings. To acquire good quality and quantity of DNA for the AFLP technique, several methods were undertaken to isolate DNA of potato tuber moth male from different developmental stages especially from adult stage. However, a method called Modified M5 was used. By Modified M5, which required phenol for the isolation of DNA, in some samples 8 to 12 Mg were obtained from one insect with 95-100% purity. In our study, AFLP technique was used to analyze the DNA samples of irradiated and unirradiated males from required mating. The result analysis showed that there was a clear genetic variability between examined individuals. However, the relationship between unirradiated F1 and F2 males was stronger than that between irradiated males. Thus, our result demonstrates that the AFLP could be efficiently utilized for studying genetic variation between insect species or between individuals of the same line which have biological differences induced by several factors such as irradiation. Moreover, this technique could enhance the effectiveness of sterile insect technique by using the AFLP in the monitoring system of released insects. (author)

Individual response to ionising radiation: What predictive assay(s) to choose?

International Nuclear Information System (INIS)

Granzotto, A.; Viau, M.; Devic, C.; Maalouf, M.; Thomas, Ch.; Vogin, G.; Foray, N.; Granzotto, A.; Vogin, G.; Balosso, J.; Joubert, A.; Maalouf, M.; Vogin, G.; Colin, C.; Malek, K.; Balosso, J.; Colin, C.

2011-01-01

Individual response to ionizing radiation is an important information required to apply an efficient radiotherapy treatment against tumour and to avoid any adverse effects in normal tissues. In 1981, Fertil and Malaise have demonstrated that the post-irradiation local tumor control determined in vivo is correlated with clonogenic cell survival assessed in vitro. Furthermore, these authors have reminded the relevance of the concept of intrinsic radiosensitivity that is specific to each individual organ (Fertil and Malaise, 1981) [1]. To date, since clonogenicity assays are too time-consuming and do not provide any other molecular information, a plethora of research groups have attempted to determine the molecular bases of intrinsic radiosensitivity in order to propose reliable and faster predictive assays. To this aim, several approaches have been developed. Notably, the recent revolution in genomic and proteomics technologies is providing a considerable number of data but their link with radiosensitivity still remains to be elucidated. On another hand, the systematic screening of some candidate genes potentially involved in the radiation response is highlighting the complexity of the molecular and cellular mechanisms of DNA damage sensing and signalling and shows that an abnormal radiation response is not necessarily due to the impairment of one single protein. Finally, more modest approaches consisting in focusing some specific functions of DNA repair seem to provide more reliable clues to predict over-acute reactions caused by radiotherapy. In this review, we endeavored to analyse the contributions of these major approaches to predict human radiosensitivity. (authors)

A weighted least-squares lump correction algorithm for transmission-corrected gamma-ray nondestructive assay

International Nuclear Information System (INIS)

Prettyman, T.H.; Sprinkle, J.K. Jr.; Sheppard, G.A.

1993-01-01

With transmission-corrected gamma-ray nondestructive assay instruments such as the Segmented Gamma Scanner (SGS) and the Tomographic Gamma Scanner (TGS) that is currently under development at Los Alamos National Laboratory, the amount of gamma-ray emitting material can be underestimated for samples in which the emitting material consists of particles or lumps of highly attenuating material. This problem is encountered in the assay of uranium and plutonium-bearing samples. To correct for this source of bias, we have developed a least-squares algorithm that uses transmission-corrected assay results for several emitted energies and a weighting function to account for statistical uncertainties in the assay results. The variation of effective lump size in the fitted model is parameterized; this allows the correction to be performed for a wide range of lump-size distributions. It may be possible to use the reduced chi-squared value obtained in the fit to identify samples in which assay assumptions have been violated. We found that the algorithm significantly reduced bias in simulated assays and improved SGS assay results for plutonium-bearing samples. Further testing will be conducted with the TGS, which is expected to be less susceptible than the SGS to systematic source of bias

Signal transduction by normal isoforms and W mutant variants of the Kit receptor tyrosine kinase.

OpenAIRE

Reith, A D; Ellis, C; Lyman, S D; Anderson, D M; Williams, D E; Bernstein, A; Pawson, T

1991-01-01

Germline mutations at the Dominant White Spotting (W) and Steel (Sl) loci have provided conclusive genetic evidence that c-kit mediated signal transduction pathways are essential for normal mouse development. We have analysed the interactions of normal and mutant W/c-kit gene products with cytoplasmic signalling proteins, using transient c-kit expression assays in COS cells. In addition to the previously identified c-kit gene product (Kit+), a second normal Kit isoform (KitA+) containing an i...

An ECVAG trial on assessment of oxidative damage to DNA measured by the comet assay

DEFF Research Database (Denmark)

Johansson, Clara; Møller, Peter; Forchhammer, Lykke

2010-01-01

The increasing use of single cell gel electrophoresis (the comet assay) highlights its popularity as a method for detecting DNA damage, including the use of enzymes for assessment of oxidatively damaged DNA. However, comparison of DNA damage levels between laboratories can be difficult due...... to differences in assay protocols (e.g. lysis conditions, enzyme treatment, the duration of the alkaline treatment and electrophoresis) and in the end points used for reporting results (e.g. %DNA in tail, arbitrary units, tail moment and tail length). One way to facilitate comparisons is to convert primary comet...... assay end points to number of lesions/10(6) bp by calibration with ionizing radiation. The aim of this study was to investigate the inter-laboratory variation in assessment of oxidatively damaged DNA by the comet assay in terms of oxidized purines converted to strand breaks with formamidopyrimidine DNA...

Radioreceptor opioid assay

International Nuclear Information System (INIS)

Miller, R.J.; Chang, K.-J.

1981-01-01

A radioreceptor assay is described for assaying opioid drugs in biological fluids. The method enables the assay of total opioid activity, being specific for opioids as a class but lacking specificity within the class. A radio-iodinated opioid and the liquid test sample are incubated with an opiate receptor material. The percentage inhibition of the binding of the radio-iodinated compound to the opiate receptor is calculated and the opioid activity of the test liquid determined from a standard curve. Examples of preparing radio-iodinated opioids and assaying opioid activity are given. A test kit for the assay is described. Compared to other methods, this assay is cheap, easy and rapid. (U.K.)

Time dependent analysis of assay comparability: a novel approach to understand intra- and inter-site variability over time

Science.gov (United States)

Winiwarter, Susanne; Middleton, Brian; Jones, Barry; Courtney, Paul; Lindmark, Bo; Page, Ken M.; Clark, Alan; Landqvist, Claire

2015-09-01

We demonstrate here a novel use of statistical tools to study intra- and inter-site assay variability of five early drug metabolism and pharmacokinetics in vitro assays over time. Firstly, a tool for process control is presented. It shows the overall assay variability but allows also the following of changes due to assay adjustments and can additionally highlight other, potentially unexpected variations. Secondly, we define the minimum discriminatory difference/ratio to support projects to understand how experimental values measured at different sites at a given time can be compared. Such discriminatory values are calculated for 3 month periods and followed over time for each assay. Again assay modifications, especially assay harmonization efforts, can be noted. Both the process control tool and the variability estimates are based on the results of control compounds tested every time an assay is run. Variability estimates for a limited set of project compounds were computed as well and found to be comparable. This analysis reinforces the need to consider assay variability in decision making, compound ranking and in silico modeling.

Spinal cord normalization in multiple sclerosis.

Science.gov (United States)

Oh, Jiwon; Seigo, Michaela; Saidha, Shiv; Sotirchos, Elias; Zackowski, Kathy; Chen, Min; Prince, Jerry; Diener-West, Marie; Calabresi, Peter A; Reich, Daniel S

2014-01-01

Spinal cord (SC) pathology is common in multiple sclerosis (MS), and measures of SC-atrophy are increasingly utilized. Normalization reduces biological variation of structural measurements unrelated to disease, but optimal parameters for SC volume (SCV)-normalization remain unclear. Using a variety of normalization factors and clinical measures, we assessed the effect of SCV normalization on detecting group differences and clarifying clinical-radiological correlations in MS. 3T cervical SC-MRI was performed in 133 MS cases and 11 healthy controls (HC). Clinical assessment included expanded disability status scale (EDSS), MS functional composite (MSFC), quantitative hip-flexion strength ("strength"), and vibration sensation threshold ("vibration"). SCV between C3 and C4 was measured and normalized individually by subject height, SC-length, and intracranial volume (ICV). There were group differences in raw-SCV and after normalization by height and length (MS vs. HC; progressive vs. relapsing MS-subtypes, P normalization by length (EDSS:r = -.43; MSFC:r = .33; strength:r = .38; vibration:r = -.40), and height (EDSS:r = -.26; MSFC:r = .28; strength:r = .22; vibration:r = -.29), but diminished with normalization by ICV (EDSS:r = -.23; MSFC:r = -.10; strength:r = .23; vibration:r = -.35). In relapsing MS, normalization by length allowed statistical detection of correlations that were not apparent with raw-SCV. SCV-normalization by length improves the ability to detect group differences, strengthens clinical-radiological correlations, and is particularly relevant in settings of subtle disease-related SC-atrophy in MS. SCV-normalization by length may enhance the clinical utility of measures of SC-atrophy. Copyright © 2014 by the American Society of Neuroimaging.

Diural TSH variations in hypothyroidism.

Science.gov (United States)

Weeke, J; Laurberg, P

1976-07-01

There is a circadian variation in serum TSH in euthyroid subjects. A similar diurnal variation has been demonstrated in patients with hypothyroidism. In the present study the 24-hour pattern of serum TSH was investigated in eight patients with hypothyroidism of varying severity and in five hypothyroid patients treated with thyroxine (T4). There was a circadian variation in serum TSH in patients with hypothyroidism of moderate degree, and in patients treated for severe hypothyrodism with thyroxine. The pattern was similar to that found in normal subjects, i.e., low TSH levels in the daytime and higher levels at night. In severely hypothyroid patients, no diurnal variation in serum TSH was observed. A practical consequence is that blood samples for TSH measurements in patients with moderately elevated TSH levels are best taken after 1100 h, when the low day levels are reached.

Diurnal Variations in Serum Glucose, Insulin and C-Peptide of Normal Korean Adults

International Nuclear Information System (INIS)

Choi, Du Hyok; Chung, June Key; Lee, Hong Kyu; Koh, Chang Soon; Hong, Kee Suk

1983-01-01

It is already well known that many factors are involved in maintaining normal blood glucose level. The amount and components of meal are also thought to be some of the factors which affect the blood glucose and insulin levels. It is reported that as for Koreans sugar takes up over 75% out of 2,098 kcal, the average daily calorie intake per adult. It implies that Koreans take a high-sugar diet compared with Westerners who take 40-50% of sugar out of their total average daily calorie. For the purpose of studying diurnal variations in serum glucose, insulin and C-peptide of normal Koreans adults based on ordinary Korean diet, we selected 13 normal Korean male adults and divided them into two groups, Group I (7 persons) and Group II (6 persons). We put Group I on 3,100 kcal and 75% sugar diet, and Group II on 2,100 kcal and 69% sugar diet per day for over 4 days. Serum glucose, insulin and C-peptide were checked every 30 minutes or every hour throughout 2 hour. Results are as follows: 1. As for serum glucose level, in the preprandial fasting state in the morning, mean±S.D. of Group I was 91.1±3.2 mg%, while that of Group II is 82.5±4.4 mg%. Both groups showed peaks of increased glucose level t postprandial 1 hour after each meal. The peak returned to the level shown during the fasting state at postprandial 1 hour after breakfast while the relatively high glucose levels were maintained respectively even for 2 or 3 hours after lunch and dinner. 2. As for serum insults level, Group I showed mean±S.D. of 14.7±3.0 μU/ml while Group II shows that of 7.0±2.6 μU/ml in the fasting state. Group I particularly showed the largest peak from preprandial a half or one and half an hour to postprandial one hour of lunch, and made relatively small peaks (47.7±10.8 μU/ml) at postprandial 1 hour after breakfast and dinner. No such large peak was marked in Group II, though it showed relatively similar patterns of peak after each meal. 3. As for C-peptide, in the fasting state

Diurnal Variations in Serum Glucose, Insulin and C-Peptide of Normal Korean Adults

Energy Technology Data Exchange (ETDEWEB)

Choi, Du Hyok; Chung, June Key; Lee, Hong Kyu; Koh, Chang Soon [Seoul National University College of Medicine, Seoul (Korea, Republic of); Hong, Kee Suk [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

1983-03-15

It is already well known that many factors are involved in maintaining normal blood glucose level. The amount and components of meal are also thought to be some of the factors which affect the blood glucose and insulin levels. It is reported that as for Koreans sugar takes up over 75% out of 2,098 kcal, the average daily calorie intake per adult. It implies that Koreans take a high-sugar diet compared with Westerners who take 40-50% of sugar out of their total average daily calorie. For the purpose of studying diurnal variations in serum glucose, insulin and C-peptide of normal Koreans adults based on ordinary Korean diet, we selected 13 normal Korean male adults and divided them into two groups, Group I (7 persons) and Group II (6 persons). We put Group I on 3,100 kcal and 75% sugar diet, and Group II on 2,100 kcal and 69% sugar diet per day for over 4 days. Serum glucose, insulin and C-peptide were checked every 30 minutes or every hour throughout 2 hour. Results are as follows: 1. As for serum glucose level, in the preprandial fasting state in the morning, mean+-S.D. of Group I was 91.1+-3.2 mg%, while that of Group II is 82.5+-4.4 mg%. Both groups showed peaks of increased glucose level t postprandial 1 hour after each meal. The peak returned to the level shown during the fasting state at postprandial 1 hour after breakfast while the relatively high glucose levels were maintained respectively even for 2 or 3 hours after lunch and dinner. 2. As for serum insults level, Group I showed mean+-S.D. of 14.7+-3.0 muU/ml while Group II shows that of 7.0+-2.6 muU/ml in the fasting state. Group I particularly showed the largest peak from preprandial a half or one and half an hour to postprandial one hour of lunch, and made relatively small peaks (47.7+-10.8 muU/ml) at postprandial 1 hour after breakfast and dinner. No such large peak was marked in Group II, though it showed relatively similar patterns of peak after each meal. 3. As for C-peptide, in the fasting state

Polymorphic Variation in Double Strand Break Repair Gene in Indian Population: A Comparative Approach with Worldwide Ethnic Group Variations.

Science.gov (United States)

Mandal, Raju Kumar; Mittal, Rama Devi

2018-04-01

DNA repair capacity is essential in maintaining cellular functions and homeostasis. Identification of genetic polymorphisms responsible for reduced DNA repair capacity may allow better cancer prevention. Double strand break repair pathway plays critical roles in maintaining genome stability. Present study was conducted to determine distribution of XRCC3 Exon 7 (C18067T, rs861539) and XRCC7 Intron 8 (G6721T, rs7003908) gene polymorphisms in North Indian population and compare with different populations globally. The genotype assays were performed in 224 normal healthy individuals of similar ethnicity using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Allelic frequencies of wild type were 79% (C) in XRCC3 Exon 7 C > T and 57% (G) in XRCC7 Intron 8 (G > T) 57% (G) observed. On the other hand, the variant allele frequency were 21% (T) in XRCC3 Exon 7 C > T and 43% (T) in XRCC7 Intron 8 G > T respectively. Major differences from other ethnic populations were observed. Our results suggest that frequency in these DNA repair genes exhibit distinctive pattern in India that could be attributed to ethnicity variation. This could assist in high-risk screening of humans exposed to environmental carcinogens and cancer predisposition in different ethnic groups.

Dosimetric precision requirements and quantities for characterizing the response of tumors and normal tissues

Energy Technology Data Exchange (ETDEWEB)

Brahme, A [Karolinska Inst., Stockholm (Sweden). Dept. of Radiation Physics

1996-08-01

Based on simple radiobiological models the effect of the distribution of absorbed dose in therapy beams on the radiation response of tumor and normal tissue volumes are investigated. Under the assumption that the dose variation in the treated volume is small it is shown that the response of the tissue to radiation is determined mainly by the mean dose to the tumor or normal tissue volume in question. Quantitative expressions are also given for the increased probability of normal tissue complications and the decreased probability of tumor control as a function of increasing dose variations around the mean dose level to these tissues. When the dose variations are large the minimum tumor dose (to cm{sup 3} size volumes) will generally be better related to tumor control and the highest dose to significant portions of normal tissue correlates best to complications. In order not to lose more than one out of 20 curable patients (95% of highest possible treatment outcome) the required accuracy in the dose distribution delivered to the target volume should be 2.5% (1{sigma}) for a mean dose response gradient {gamma} in the range 2 - 3. For more steeply responding tumors and normal tissues even stricter requirements may be desirable. (author). 15 refs, 6 figs.

Response of cultured normal human mammary epithelial cells to X rays

International Nuclear Information System (INIS)

Yang, T.C.; Stampfer, M.R.; Smith, H.S.

1983-01-01

The effect of X rays on the reproductive death of cultured normal human mammary epithelial cells was examined. Techniques were developed for isolating and culturing normal human mammary epithelial cells which provide sufficient cells at second passage for radiation studies, and an efficient clonogenic assay suitable for measuring radiation survival curves. It was found that the survival curves for epithelial cells from normal breast tissue were exponential and had D 0 values of about 109-148 rad for 225 kVp X rays. No consistent change in cell radiosensitivity with the age of donor was observed, and no sublethal damage repair in these cells could be detected with the split-dose technique

The need for a sufficient number of low level sera in comparisons of different serum vitamin B12 assays

International Nuclear Information System (INIS)

Gijzen, A.H.J.; Kock, H.W. de; Meulendijk, P.N.; Schmidt, N.A.; Schopman, W.; Tertoolen, J.F.W.; Voogd, C.E.

1983-01-01

Eight radiochemical methods for the assay of vitamin B 12 in serum were compared with the microbiological assay with Lactobacillus leichmannii ATCC 7830 using 198 individual sera of patients. There was a good agreement between the results of most samples with some kits and the microbiological assay. However, especially in the sera of vitamin B 12 -deficient patients large discrepancies between the results could occur. These variations were due to both the kits used and the performance of the assays in different laboratories. A sufficient number of non-pooled sera of vitamin B 12 -deficient patients should be included in investigations to validate radiochemical methods. (Auth.)

Normal anatomy of lung perfusion SPECT scintigraphy

International Nuclear Information System (INIS)

Moskowitz, G.W.; Levy, L.M.

1987-01-01

Ten patients studies for possible pulmonary embolic disease had normal lung perfusion planar and SPECT scintigraphy. A computer program was developed to superimpose the CT scans on corresponding SPECT images. Superimposition of CT scans on corresponding SPECT transaxial cross-sectional images, when available, provides the needed definition and relationships of adjacent organs. SPECT transaxial sections provide clear anatomic definition of perfusion defects without foreground and background lung tissue superimposed. The location, shape, and size of the perfusion defects can be readily assessed by SPECT. An algorithm was developed for the differentiation of abnormal pulmonary perfusion patterns from normal structures on variation

Multi-site analytical evaluation of the Abbott ARCHITECT tacrolimus assay.

Science.gov (United States)

Wallemacq, Pierre; Goffinet, Jean-Sebastien; O'Morchoe, Susan; Rosiere, Thomas; Maine, Gregory T; Labalette, Myriam; Aimo, Giuseppe; Dickson, Diana; Schmidt, Ed; Schwinzer, Reinhard; Schmid, Rainer W

2009-04-01

The objective of this study was to evaluate the analytical performance of the Abbott ARCHITECT Tacrolimus immunoassay. Proficiency panels and specimens from a population of organ transplant recipients were analyzed in 6 clinical laboratories in Europe and the United States, and the results were compared with other methods. The ARCHITECT assay requires a whole blood specimen pretreatment step with methanol/zinc sulfate to precipitate protein and extract the drug, followed by a 30-minute immunoassay using anti-tacrolimus antibody-coated paramagnetic microparticles and an acridinium-tacrolimus tracer. The assay was free from hematocrit interference in the range 25%-55% and from interference by extremes of cholesterol, triglycerides, bilirubin, total protein, and uric acid. The total percent of coefficient of variations of the assay were 4.9%-7.6% at 3 ng/mL, 2.9%-4.6% at 8.6 ng/mL, and 3.1%-8.2% at 15.5 ng/mL. Limit of detection was Abbott IMx Tacrolimus II immunoassay (4 sites) yielded average biases between -0.94 and +0.26 ng/mL; ARCHITECT assay versus the Dade Dimension Tacrolimus immunoassay (2 sites) yielded average biases of -0.46 and +0.11 ng/mL; and ARCHITECT assay versus LC-MSMS methods at 2 sites yielded average biases of +0.51 and +1.63 ng/mL. Spearman correlation coefficients were >/=0.90 on all method comparisons. The ARCHITECT Tacrolimus assay is a semiautomated, robust, and highly sensitive immunoassay, representing an alternative approach for laboratories not equipped with LC-MSMS, and meets the 1 ng/mL recommendation of LOQ by the European Consensus Conference on Tacrolimus Optimization.

Anatomical Variations of the Circulus Arteriosus in Cadaveric Human Brains

Science.gov (United States)

Gunnal, S. A.; Farooqui, M. S.; Wabale, R. N.

2014-01-01

Objective. Circulus arteriosus/circle of Willis (CW) is a polygonal anastomotic channel at the base of the brain which unites the internal carotid and vertebrobasilar system. It maintains the steady and constant supply to the brain. The variations of CW are seen often. The Aim of the present work is to find out the percentage of normal pattern of CW, and the frequency of variations of the CW and to study the morphological and morphometric aspects of all components of CW. Methods. Circulus arteriosus of 150 formalin preserved brains were dissected. Dimensions of all the components forming circles were measured. Variations of all the segments were noted and well photographed. The variations such as aplasia, hypoplasia, duplication, fenestrations, and difference in dimensions with opposite segments were noted. The data collected in the study was analyzed. Results. Twenty-one different types of CW were found in the present study. Normal and complete CW was found in 60%. CW with gross morphological variations was seen in 40%. Maximum variations were seen in the PCoA followed by the ACoA in 50% and 40%, respectively. Conclusion. As it confirms high percentage of variations, all surgical interventions should be preceded by angiography. Awareness of these anatomical variations is important in neurovascular procedures. PMID:24891951

Monoclonal antibodies to human factor VII: production of immunodepleted plasma for VII:C assays.

OpenAIRE

Takase, T; Tuddenham, E G; Chand, S; Goodall, A H

1988-01-01

A high affinity monoclonal antibody to factor VII (RFF-VII/1), coupled to sepharose, was used to immunodeplete factor VII from normal plasma. The plasma could be used as a substrate in a one stage coagulation assay and performed as well as, or better than, commercially available factor VII deficient plasma or plasma from congenitally deficient factor VII patients. Plasma from normal donors (n = 20), patients with liver disease (n = 20), and patients receiving warfarin (n = 20), or congenitall...

The fibrocartilaginous sesamoid: a cause of size and signal variation in the normal distal posterior tibial tendon

Energy Technology Data Exchange (ETDEWEB)

Delfaut, E.M.; Bieganski, A.; Cotten, A. [Department of Skeletal Radiology, Roger Salengro Hospital, CHRU of Lille, Bd du Professeur Jules Leclercq, 59037, Lille Cedex (France); Demondion, X. [Department of Skeletal Radiology, Roger Salengro Hospital, CHRU of Lille, Bd du Professeur Jules Leclercq, 59037, Lille Cedex (France); Department of Anatomy, Faculty of Medicine, Place de Verdun, 59037, Lille Cedex (France); Cotten, H. [Pathology Laboratory, 128 Bd de la Liberte, 59000, Lille Cedex (France); Mestdagh, H. [Department of Orthopaedic Surgery, Roger Salengro Hospital, CHRU of Lille, Bd du Professeur Jules Leclercq, 59037, Lille Cedex (France)

2003-12-01

The aim of this study was to investigate the presence of fibrocartilage within the distal posterior tibial tendon (PTT) before its division correlating with size and signal variation on MR images through a radio-anatomic and pathologic study. Eight fresh cadaveric feet underwent MR imaging were cut into 4-mm slices in the axial plane. The PTT specimens were harvested at the tendon distal portion before its division and sent to pathology. Thirty-three asymptomatic subjects underwent axial double-echo turbo-spin-echo MR imaging. Proximal and distal PTT signal and diameter were evaluated. In cadavers, every PTT flared distally. Intratendinous fibrocartilage and ossified sesamoid were found in, respectively, 87.5 and 12.5% of the cases. Distal PTT flaring was demonstrated in 100% of the asymptomatic subjects (mean diameter 8 mm). An intratendinous high signal intensity on proton-density-weighted images and sesamoid bone were evidenced in, respectively, 36 and 33% of the cases. Proximally, PTT presented a 4-mm mean diameter and was hypointense in 100% of the cases. Only one accessory navicular bone was detected. Laterally off-centered increased intratendinous signal intensity as well as PTT distal widening with otherwise normal MR imaging features are related to an intratendinous fibrocartilage. (orig.)

Enzyme-Linked Immunosorbent Assay (ELISA).

Science.gov (United States)

Konstantinou, George N

2017-01-01

Food allergy is a public health concern especially after recognizing its constantly increased prevalence and severity. Despite careful reading of food ingredient statements, food allergic individuals may experience reactions caused by "hidden", "masked", or "contaminated" proteins that are known major allergens. Many techniques have been developed to detect even small traces of food allergens, for clinical or laboratory purposes. Enzyme-linked immunosorbent assay (ELISA) is one of the best validated and most routinely used immunoassay in allergy research, in allergy diagnosis in allergy-related quality control in various industries. Although as a technique it has been implemented for the last 45 years, the evolution in biochemistry allowed the development of ultrasensitive ELISA variations that are capable of measuring quantities in the scale of picograms, rendering ELISA attractive, robust, and very famous.

Prostate-Specific Natural Health Products (Dietary Supplements) Radiosensitize Normal Prostate Cells

International Nuclear Information System (INIS)

Hasan, Yasmin; Schoenherr, Diane; Martinez, Alvaro A.; Wilson, George D.; Marples, Brian

2010-01-01

Purpose: Prostate-specific health products (dietary supplements) are taken by cancer patients to alleviate the symptoms linked with poor prostate health. However, the effect of these agents on evidence-based radiotherapy practice is poorly understood. The present study aimed to determine whether dietary supplements radiosensitized normal prostate or prostate cancer cell lines. Methods and Materials: Three well-known prostate-specific dietary supplements were purchased from commercial sources available to patients (Trinovin, Provelex, and Prostate Rx). The cells used in the study included normal prostate lines (RWPE-1 and PWR-1E), prostate tumor lines (PC3, DU145, and LNCaP), and a normal nonprostate line (HaCaT). Supplement toxicity was assessed using cell proliferation assays [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] and cellular radiosensitivity using conventional clonogenic assays (0.5-4Gy). Cell cycle kinetics were assessed using the bromodeoxyuridine/propidium iodide pulse-labeling technique, apoptosis by scoring caspase-3 activation, and DNA repair by assessing γH2AX. Results: The cell growth and radiosensitivity of the malignant PC3, DU145, and LNcaP cells were not affected by any of the dietary prostate supplements (Provelex [2μg/mL], Trinovin [10μg/mL], and Prostate Rx [50 μg/mL]). However, both Trinovin (10μg/mL) and Prostate Rx (6μg/mL) inhibited the growth rate of the normal prostate cell lines. Prostate Rx increased cellular radiosensitivity of RWPE-1 cells through the inhibition of DNA repair. Conclusion: The use of prostate-specific dietary supplements should be discouraged during radiotherapy owing to the preferential radiosensitization of normal prostate cells.

Development of a high-throughput colorimetric Zika virus infection assay.

Science.gov (United States)

Müller, Janis A; Harms, Mirja; Schubert, Axel; Mayer, Benjamin; Jansen, Stephanie; Herbeuval, Jean-Philippe; Michel, Detlef; Mertens, Thomas; Vapalahti, Olli; Schmidt-Chanasit, Jonas; Münch, Jan

2017-04-01

Zika virus (ZIKV) is an emerging pathogen that causes congenital infections which may result in birth defects, such as microcephaly. Currently, no approved treatment or vaccination is available. ZIKV can be readily detected in cell culture where virally infected cells are normally stained by specific antibodies. As ZIKV regularly causes a cytopathic effect, we were wondering whether this viral property can be used to quantitatively determine viral infectivity. We here describe the use of an 3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide-(MTT)-based cell viability assay that allows to determine ZIKV-induced cell death. We show that this colorimetric assay quantifies ZIKV infection over a broad range of viral dilutions in both monkey and human cells. It allows to determine inhibitory activities of antivirals that block ZIKV or to define the neutralizing antibody titers of ZIKV antisera. This MTT-based ZIKV detection assay can be evaluated by naked eye or computational tools, has a broad linear range, does not require large equipment or costly reagents, and thus represents a promising alternative to antibody-based assays, in particular in resource-poor settings. We propose to use this simple, fast, and cheap method for quantification of ZIKV neutralizing antibodies and testing of antiviral compounds.

The impact of pre-analytical variables on the stability of neurofilament proteins in CSF, determined by a novel validated SinglePlex Luminex assay and ELISA.

Science.gov (United States)

Koel-Simmelink, Marleen J A; Vennegoor, Anke; Killestein, Joep; Blankenstein, Marinus A; Norgren, Niklas; Korth, Carsten; Teunissen, Charlotte E

2014-01-15

Neurofilament (Nf) proteins have been shown to be promising biomarkers for monitoring and predicting disease progression for various neurological diseases. The aim of this study was to evaluate the effects of pre-analytical variables on the concentration of neurofilament heavy (NfH) and neurofilament light (NfL) proteins. For NfH an in-house newly-developed and validated SinglePlex Luminex assay was used; ELISA was used to analyze NfL. For the NfL ELISA assay, the intra- and inter-assay variation was respectively, 1.5% and 16.7%. Analytical performance of the NfH SinglePlex Luminex assay in terms of sensitivity (6.6pg/mL), recovery in cerebrospinal fluid (CSF) (between 90 and 104%), linearity (from 6.6-1250pg/mL), and inter- and intra-assay variation (<8%) were good. Concentrations of both NfL and NfH appeared not negatively affected by blood contamination, repeated freeze-thaw cycles (up to 4), delayed processing (up to 24hours) and during long-term storage at -20°C, 4°C, and room temperature. A decrease in concentration was observed during storage of both neurofilament proteins up to 21days at 37°C, which was significant by day 5. The newly developed NfH SinglePlex Luminex assay has a good sensitivity and is robust. Moreover, both NfH and NfL are stable under the most prevalent pre-analytical variations. Copyright © 2013 Elsevier B.V. All rights reserved.

Histogram-based normalization technique on human brain magnetic resonance images from different acquisitions.

Science.gov (United States)

Sun, Xiaofei; Shi, Lin; Luo, Yishan; Yang, Wei; Li, Hongpeng; Liang, Peipeng; Li, Kuncheng; Mok, Vincent C T; Chu, Winnie C W; Wang, Defeng

2015-07-28

Intensity normalization is an important preprocessing step in brain magnetic resonance image (MRI) analysis. During MR image acquisition, different scanners or parameters would be used for scanning different subjects or the same subject at a different time, which may result in large intensity variations. This intensity variation will greatly undermine the performance of subsequent MRI processing and population analysis, such as image registration, segmentation, and tissue volume measurement. In this work, we proposed a new histogram normalization method to reduce the intensity variation between MRIs obtained from different acquisitions. In our experiment, we scanned each subject twice on two different scanners using different imaging parameters. With noise estimation, the image with lower noise level was determined and treated as the high-quality reference image. Then the histogram of the low-quality image was normalized to the histogram of the high-quality image. The normalization algorithm includes two main steps: (1) intensity scaling (IS), where, for the high-quality reference image, the intensities of the image are first rescaled to a range between the low intensity region (LIR) value and the high intensity region (HIR) value; and (2) histogram normalization (HN),where the histogram of low-quality image as input image is stretched to match the histogram of the reference image, so that the intensity range in the normalized image will also lie between LIR and HIR. We performed three sets of experiments to evaluate the proposed method, i.e., image registration, segmentation, and tissue volume measurement, and compared this with the existing intensity normalization method. It is then possible to validate that our histogram normalization framework can achieve better results in all the experiments. It is also demonstrated that the brain template with normalization preprocessing is of higher quality than the template with no normalization processing. We have proposed

Evaluation of the Thermo Scientific™ SureTect™ Salmonella species Assay.

Science.gov (United States)

Cloke, Jonathan; Clark, Dorn; Radcliff, Roy; Leon-Velarde, Carlos; Larson, Nathan; Dave, Keron; Evans, Katharine; Crabtree, David; Hughes, Annette; Simpson, Helen; Holopainen, Jani; Wickstrand, Nina; Kauppinen, Mikko

2014-03-01

The Thermo Scientific™ SureTect™ Salmonella species Assay is a new real-time PCR assay for the detection of Salmonellae in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested MethodsSM program to validate the SureTect Salmonella species Assay in comparison to the reference method detailed in International Organization for Standardization 6579:2002 in a variety of food matrixes, namely, raw ground beef, raw chicken breast, raw ground pork, fresh bagged lettuce, pork frankfurters, nonfat dried milk powder, cooked peeled shrimp, pasteurized liquid whole egg, ready-to-eat meal containing beef, and stainless steel surface samples. With the exception of liquid whole egg and fresh bagged lettuce, which were tested in-house, all matrixes were tested by Marshfield Food Safety, Marshfield, WI, on behalf of Thermo Fisher Scientific. In addition, three matrixes (pork frankfurters, lettuce, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled laboratory study by the University of Guelph, Canada. No significant difference by probability of detection or McNemars Chi-squared statistical analysis was found between the candidate or reference methods for any of the food matrixes or environmental surface samples tested during the validation study. Inclusivity and exclusivity testing was conducted with 117 and 36 isolates, respectively, which demonstrated that the SureTect Salmonella species Assay was able to detect all the major groups of Salmonella enterica subspecies enterica (e.g., Typhimurium) and the less common subspecies of S. enterica (e.g., arizoniae) and the rarely encountered S. bongori. None of the exclusivity isolates analyzed were detected by the SureTect Salmonella species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation

Variation in aerodynamic coefficients with altitude

Directory of Open Access Journals (Sweden)

Faiza Shahid

Full Text Available Precise aerodynamics performance prediction plays key role for a flying vehicle to get its mission completed within desired accuracy. Aerodynamic coefficients for same Mach number can be different at different altitude due to difference in Reynolds number. Prediction of these aerodynamics coefficients can be made through experiments, analytical solution or Computational Fluid Dynamics (CFD. Advancements in computational power have generated the concept of using CFD as a virtual Wind Tunnel (WT, hence aerodynamic performance prediction in present study is based upon CFD (numerical test rig. Simulations at different altitudes for a range of Mach numbers with zero angle of attack are performed to predict axial force coefficient behavior with altitude (Reynolds number. Similar simulations for a fixed Mach number ‘3’ and a range of angle of attacks are also carried out to envisage the variation in normal force and pitching moment coefficients with altitude (Reynolds number. Results clearly depict that the axial force coefficient is a function of altitude (Reynolds number and increase as altitude increases, especially for subsonic region. Variation in axial force coefficient with altitude (Reynolds number slightly increases for larger values of angle of attacks. Normal force and pitching moment coefficients do not depend on altitude (Reynolds number at smaller values of angle of attacks but show slight decrease as altitude increases. Present study suggests that variation of normal force and pitching moment coefficients with altitude can be neglected but the variation of axial force coefficient with altitude should be considered for vehicle fly in dense atmosphere. It is recommended to continue this study to more complex configurations for various Mach numbers with side slip and real gas effects. Keywords: Mach number, Reynolds number, Blunt body, Altitude effect, Angle of attacks

Clinical performance of a new hepatitis B surface antigen quantitative assay with automatic dilution

Directory of Open Access Journals (Sweden)

Ta-Wei Liu

2015-01-01

Full Text Available Hepatitis B virus surface antigen (HBsAg levels reflect disease status and can predict the clinical response to antiviral treatment; however, the emergence of HBsAg mutant strains has become a challenge. The Abbott HBsAg quantification assay provides enhanced detection of HBsAg and HBsAg mutants. We aimed to evaluate the performance of the Abbott HBsAg quantification assay with automatic sample dilutions (shortened as automatic Architect assay, compared with the Abbott HBsAg quantification assay with manual sample dilutions (shortened as manual Architect assay and the Roche HBsAg quantification assay with automatic sample dilutions (shortened as Elecsys. A total of 130 sera samples obtained from 87 hepatitis B virus (HBV-infected patients were collected to assess the correlation between the automatic and manual Architect assays. Among the 87 patients, 41 provided 42 sera samples to confirm the linearity and reproducibility of the automatic Architect assay, and find out the correlation among the Elecsys and two Architect assays. The coefficients of variation (0.44–9.53% and R2 = 0.996–1, which were both determined using values obtained from the automatic Architect assay, showed good reproducibility and linearity. Results of the two Architect assays demonstrated a feasible correlation (n = 130 samples; R = 0.898, p  0.93 in all cases. In conclusion, the correlation between the automatic and manual dilution Architect assays was feasible, particularly in the HBeAg-negative and low DNA groups. With lower labor costs and less human error than the manual version, the Abbott automatic dilution Architect assay provided a good clinical performance with regard to the HBsAg levels.

A method for assay of special nuclear material in high level liquid waste streams

International Nuclear Information System (INIS)

Venkata Subramani, C.R.; Swaminathan, K.; Asuvathraman, R.; Kutty, K.V.G.

2003-01-01

The assay of special nuclear material in the high level liquid waste streams assumes importance as this is the first stage in the extraction cycle and considerable losses of plutonium could occur here. This stream contains all the fission products as also the minor actinides and hence normal nuclear techniques cannot be used without prior separation of the special nuclear material. This paper presents the preliminary results carried out using wavelength dispersive x-ray fluorescence as part of the developmental efforts to assay SNM in these streams by instrumental techniques. (author)

Analysis of a Dynamic Viscoelastic Contact Problem with Normal Compliance, Normal Damped Response, and Nonmonotone Slip Rate Dependent Friction

Directory of Open Access Journals (Sweden)

Mikaël Barboteu

2016-01-01

Full Text Available We consider a mathematical model which describes the dynamic evolution of a viscoelastic body in frictional contact with an obstacle. The contact is modelled with a combination of a normal compliance and a normal damped response law associated with a slip rate-dependent version of Coulomb’s law of dry friction. We derive a variational formulation and an existence and uniqueness result of the weak solution of the problem is presented. Next, we introduce a fully discrete approximation of the variational problem based on a finite element method and on an implicit time integration scheme. We study this fully discrete approximation schemes and bound the errors of the approximate solutions. Under regularity assumptions imposed on the exact solution, optimal order error estimates are derived for the fully discrete solution. Finally, after recalling the solution of the frictional contact problem, some numerical simulations are provided in order to illustrate both the behavior of the solution related to the frictional contact conditions and the theoretical error estimate result.

Evaluation of the transforming growth factor-beta activity in normal and dry eye human tears by CCL-185 cell bioassay.

Science.gov (United States)

Zheng, Xiaofen; De Paiva, Cintia S; Rao, Kavita; Li, De-Quan; Farley, William J; Stern, Michael; Pflugfelder, Stephen C

2010-09-01

To develop a new bioassay method using human lung epithelial cells (CCL-185) to assess activity of transforming growth factor beta (TGF-beta) in human tear fluid from normal subjects and patients with dry eye. Two epithelial cell lines, mink lung cells (CCL-64) and human lung cells (CCL-185), were compared to detect the active form of TGF-beta by BrdU incorporation (quantitation of cell DNA synthesis) and WST assay (metabolic activity of viable cells). The effect of TGF-beta on the growth of CCL-185 cells was observed microscopically. Human tears from normal control subjects and patients with dry eye (DE) with and without Sjögren syndrome were evaluated for TGF-beta concentration by Luminex microbead assay, and TGF-beta activity by the CCL-185 cell growth inhibition bioassay. The metabolic activity of viable CCL-185 cells, measured by WST, was shown to be proportional to the TGF-beta1 concentration (R = 0.919) and confirmed by BrdU assay (R = 0.969). Compared with CCL-185, metabolic activity of viable cells and DNA synthesis, measured by WST and BrdU incorporation assays, were shown to be less proportional to the TGF-beta1 concentration in the CCL-64 line (R = 0.42 and 0.17, respectively). Coincubation with human anti-TGF-beta1 antibody (MAB-240) yielded a dose-dependent inhibition of TGF-beta1 (0.3 ng/mL) activity. CCL-185 cell growth observed microscopically was noted to decrease in response to increasing TGF-beta1 concentrations. Levels of immuodetectable TGF-beta1 and TGF-beta2 were similar in normal and DE tears. TGF-beta bioactivity in DE human tears measured by the CCL-185 cells assay was found to be higher (9777.5 +/- 10481.9 pg/mL) than those in normal controls (4129.3 +/- 1342.9 pg/mL) (P tears and 37.6% TGF-beta in normal tears were found to be biologically active. The CCL-185 cell assay was found to be a suitable tool for assessing TGF-beta activity in human tears. Tear TGF-beta bioactivity increases in DE, particularly in Sjögren syndrome, where

Methods of Reducing Bias in Combined Thermal/Epithermal Neutron (CTEN) Assays of Heterogeneous Waste

Energy Technology Data Exchange (ETDEWEB)

Estep, R.J.; Melton, S.; Miko, D.

1998-11-17

We examined the effectiveness of two different methods for correcting CTEN passive and active assays for bias due to variations in the source position in different drum types. Both use the same drum-averaged correction determined from a neural network trained to active flux monitor ratios as a starting point. One method then uses a neural network to obtain a spatial correction factor sensitive to the source location. The other method uses emission tomography. Both methods were found to give significantly improved assay accuracy over the drum-averaged correction, although more study is needed to determine which method works better.

Methods of Reducing Bias in Combined Thermal/Epithermal Neutron (CTEN) Assays of Heterogeneous Waste

International Nuclear Information System (INIS)

Estep, R.J.; Melton, S.; Miko, D.

1998-01-01

We examined the effectiveness of two different methods for correcting CTEN passive and active assays for bias due to variations in the source position in different drum types. Both use the same drum-averaged correction determined from a neural network trained to active flux monitor ratios as a starting point. One method then uses a neural network to obtain a spatial correction factor sensitive to the source location. The other method uses emission tomography. Both methods were found to give significantly improved assay accuracy over the drum-averaged correction, although more study is needed to determine which method works better

Selection of non-destructive assay methods: Neutron counting or calorimetric assay?

International Nuclear Information System (INIS)

Cremers, T.L.; Wachter, J.R.

1994-01-01

The transition of DOE facilities from production to D ampersand D has lead to more measurements of product, waste, scrap, and other less attractive materials. Some of these materials are difficult to analyze by either neutron counting or calorimetric assay. To determine the most efficacious analysis method, variety of materials, impure salts and hydrofluorination residues have been assayed by both calorimetric assay and neutron counting. New data will be presented together with a review of published data. The precision and accuracy of these measurements are compared to chemistry values and are reported. The contribution of the gamma ray isotopic determination measurement to the overall error of the calorimetric assay or neutron assay is examined and discussed. Other factors affecting selection of the most appropriate non-destructive assay method are listed and considered

Phenotypic assays for the determination of coreceptor tropism in HIV-1 infected individuals.

Science.gov (United States)

Braun, Patrick; Wiesmann, Frank

2007-10-15

Coreceptor tropism antagonists represent a new class of antiretrovirals for the treatment of HIV infection. The knowledge of patients' viral population tropism before the initiation of and during therapy with such compounds may be critical in order to optimize treatment strategies. In this review we focus on the characteristics of phenotypic assays for the determination of HIV coreceptor tropism. Beside traditional phenotypic assays, there are at least four phenotypic recombinant virus assays (RVA) available to predict coreceptor usage: Trofile (Monogram Biosciences), Phenoscript (VIRalliance), XtrackC/ PhenX-R (inPheno) and a platform developed by Virco. Trofile and Phenoscript represent single-cycle assays and are able to determine coreceptor tropism without cocultivation of HIV particles in cell culture. Trofile offers the most clinically validated data with currently about 25,000 analysed samples. The detection of minority variants is a limitation of all population-based assays and varies between 1 and 10%, depending on the assay used. XtrackC/PhenX-R and Virco's platform combine genotypic and phenotypic assays to analyze a patient's sample for tropism. Although all assays are validated for the assessment of coreceptor tropism in different HIV-1 subtypes, there is still a need for further evaluations. Furthermore, the establishment of cut-offs for X4 minority species will be difficult, and is affected by many factors like patient sample quality, the input volume, viral load, the detection limits and PCR variations. Overall, RVAs confirm efficiency and accuracy thus making them suitable for the clinical management of HIV infected individuals treated with coreceptor antagonists.

Stereospecific high-performance liquid chromatographic assay of sotalol in plasma.

Science.gov (United States)

Carr, R A; Foster, R T; Bhanji, N H

1991-09-01

A convenient high-performance liquid chromatographic (HPLC) assay was developed for determination of sotalol (STL) enantiomers in plasma. Following addition of the internal standard (IS; racemic atenolol), enantiomers of STL and IS were extracted using ethyl acetate. After evaporation of the organic layer, samples were derivatized with a solution of S-(+)-1-(1-naphthyl)ethyl isocyanate (NEIC). The resulting diastereomers were chromatographed with normal-phase HPLC with chloroform:hexane:methanol [65:33:2 (v/v)] as the mobile phase at a flow rate of 2 ml/min. The fluorescence detection wavelength was set at 220 nm for excitation with no emission filter. The suitability of the assay for pharmacokinetic studies was determined by measuring STL enantiomers in the plasma of a healthy subject after administration of a single 160-mg oral, racemic dose of STL.

Analysis of the Variation of Energetic Electron Flux with Respect to Longitude and Distance Normal to the Magnetic Equatorial Plane for Galileo Energetic Particle Detector Data

Science.gov (United States)

Swimm, R.; Garrett, H. B.; Jun, I.; Evans, R. W.

2004-12-01

In this study we examine ten-minute omni-directional averages of energetic electron data measured by the Galileo spacecraft Energetic Particle Detector (EPD). Count rates from electron channels B1, DC2, and DC3 are evaluated using a power law model to yield estimates of the differential electron fluxes from 1 MeV to 11 MeV at distances from the planet Jupiter from 8 to 28 Jupiter radii. Whereas the orbit of the Galileo spacecraft remained close to the rotational equatorial plane of Jupiter, the approximately 11 degree tilt of the magnetic axis of Jupiter relative to its rotational axis allowed the EPD instrument to sample high energy electrons at limited distances normal to the magnetic equatorial plane. We present a Fourier analysis of the semi-diurnal variation of electron radiation with longitude. We also develop a model of the electron flux with respect to distance normal to the magnetic equatorial plane as a function of the distance from Jupiter.

A universal and reliable assay for molecular sex identification of three-spined sticklebacks (Gasterosteus aculeatus).

Science.gov (United States)

Toli, E-A; Calboli, F C F; Shikano, T; Merilä, J

2016-11-01

In heterogametic species, biological differences between the two sexes are ubiquitous, and hence, errors in sex identification can be a significant source of noise and bias in studies where sex-related sources of variation are of interest or need to be controlled for. We developed and validated a universal multimarker assay for reliable sex identification of three-spined sticklebacks (Gasterosteus aculeatus). The assay makes use of genotype scores from three sex-linked loci and utilizes Bayesian probabilistic inference to identify sex of the genotyped individuals. The results, validated with 286 phenotypically sexed individuals from six populations of sticklebacks representing all major genetic lineages (cf. Pacific, Atlantic and Japan Sea), indicate that in contrast to commonly used single-marker-based sex identification assays, the developed multimarker assay should be 100% accurate. As the markers in the assay can be scored from agarose gels, it provides a quick and cost-efficient tool for universal sex identification of three-spined sticklebacks. The general principle of combining information from multiple markers to improve the reliability of sex identification is transferable and can be utilized to develop and validate similar assays for other species. © 2016 John Wiley & Sons Ltd.

A sensitive radio-immunoassay for serum thyroglobulin -including a correct screening for thyroglobulin autoantibodies

International Nuclear Information System (INIS)

Laurberg, Peter; Pedersen, K.M.

1987-01-01

A new thyroglobulin (Tg) assay employing polyethylene glycol (PEG) for separation of free and antibody bound : 125 I:Tg is described. By choosing a suitable PEG concentration the non-specific precipitation of free [ 125 I]Tg was kept low while both [ 125 I]Tg bound to rabbit anti-Tg immunoglobulins and to human Tg autoantibodies were precipitated. For all sera a 'blank' incubation with no rabbit anti-Tg immunoglobulins was run in parallel with the assay tubes. Hence any interference of Tg autoantibodies would be detected. A two-phase incubation gave a very low detection limit of 0.2 μg/l. The inter-assay coefficient of variation was 9.4% and the intra-assay coefficient of variation was 5.6%. Dilution curves of normal sera were parallel to the standard curve and Tg standards added to normal sera were recovered quantitatively. Twelve out of 60 normal sera from the Randers area contained Tg autoantibodies. The average serum Tg in the 48 sera without antibody was 44.6 ± 5.2 μg/l. (author)

Limit theorems for power variations of ambit field driven by white noise

DEFF Research Database (Denmark)

Pakkanen, Mikko S.

2014-01-01

We study the asymptotics of lattice power variations of two-parameter ambit fields driven by white noise. Our first result is a law of large numbers for power variations. Under a constraint on the memory of the ambit field, normalized power variations converge to certain integral functionals...

Transferrin receptors on human reticulocytes: variation in site number in hematologic disorders

International Nuclear Information System (INIS)

Shumak, K.H.; Rachkewich, R.A.

1984-01-01

Assays of binding of 125iodine-labeled ( 125 I) human transferrin were used to study transferrin receptor sites on reticulocytes from 15 normal subjects and from 66 patients with various hematologic disorders. In normal subjects, few or no transferrin receptors were detected whereas the average number of receptors per reticulocyte varied greatly from patient to patient, ranging from 0 to 67,700 in samples, from 35 patients, on which Scatchard analysis of binding of [ 125 I]-transferrin was done. Marked heterogeneity in the number of reticulocyte transferrin receptors in different hematologic disorders was also found in assays with [ 125 I]-OKT9 (monoclonal antibody to the human transferrin receptor). The number of receptors was not correlated with either the reticulocyte count or the hemoglobin

Correlation between the genotoxicity endpoints measured by two different genotoxicity assays: comet assay and CBMN assay

Directory of Open Access Journals (Sweden)

Carina Ladeira

2015-06-01

The results concerning of positive findings by micronuclei and non significant ones by comet assay, are corroborated by Deng et al. (2005 study performed in workers occupationally exposed to methotrexate, also a cytostatic drug. According to Cavallo et al. (2009, the comet assay seems to be more suitable for the prompt evaluation of the genotoxic effects, for instance, of polycyclic aromatic hydrocarbons mixtures containing volatile substances, whereas the micronucleus test seems more appropriate to evaluate the effects of exposure to antineoplastic agents. However, there are studies that observed an increase in both the comet assay and the micronucleus test in nurses handling antineoplastic drugs, although statistical significance was only seen in the comet assay, quite the opposite of our results (Maluf & Erdtmann, 2000; Laffon et al. 2005.

Contributions of procoagulants and anticoagulants to the international normalized ratio and thrombin generation assay in patients treated with warfarin: potential role of protein Z as a powerful determinant of coagulation assays.

Science.gov (United States)

Choi, Qute; Kim, Ji-Eun; Hyun, Jungwon; Han, Kyou-Sup; Kim, Hyun Kyung

2013-07-01

The effects of warfarin are measured with the international normalized ratio (INR). However, the thrombin generation assay (TGA) may offer more information about global coagulation. We analyzed the monitoring performance of the TGA and INR and investigated the impact of procoagulants (fibrinogen, factor (F)II, FVII, FIX, and FX) and anticoagulants (proteins C, S, and Z) on them. The TGA was performed on a calibrated automated thrombogram, producing lag time, endogenous thrombin potential (ETP), and peak thrombin in 239 patients treated with warfarin. Pro- and anticoagulant levels were also measured. The INR was significantly and inversely correlated with ETP. The therapeutic range of ETP comparable to an INR range of 2.0-3.0 was 290.1-494.6. ETP showed comparable performance to the INR as a warfarin-monitoring parameter with respect to clinical complication rate. The median levels of FII, FVII, FIX, and FX and proteins C and Z tended to decrease gradually with increasing anticoagulation intensity according to the INR or ETP. Of note, protein Z levels decreased dramatically with increasing anticoagulation status. INRs were significantly determined by FII, FVII, and protein Z. ETP was significantly dependent on FVII, and proteins C and Z concentration. Protein Z significantly reduced the total amount of thrombin generation and prolonged PT value in vitro. The INR and ETP exhibit similar efficacy for warfarin monitoring according to the clinical complication rate. Protein Z is considered to be a significant determinant of INR and ETP in patients on warfarin therapy. Copyright © 2013 Elsevier Ltd. All rights reserved.

Self-normalizing multiple-echo technique for measuring the in vivo apparent diffusion coefficient

International Nuclear Information System (INIS)

Perman, W.H.; Gado, M.; Sandstrom, J.C.

1989-01-01

This paper presents work to develop a new technique for quantitating the in vivo apparent diffusion/perfusion coefficient (ADC) by obtaining multiple data points from only two images with the capability to normalize the data from consecutive images, thus minimizing the effect of interimage variation. Two multiple-echo (six-to eight-echo) cardiac-gated images are obtained, one without and one with additional diffusion/perfusion encoding gradients placed about the 180 RF pulses of all but the first echo. Since the first echoes of both images have identical pulse sequence parameters, variations in signal intensity-between the first echoes represent image-to-image variation. The signal intensities of the subsequent echoes with additional diffusion/perfusion encoding gradients are then normalized by using the ratio of the first-echo signal intensities

Dynamic analysis of elastic rubber tired car wheel breaking under variable normal load

Science.gov (United States)

Fedotov, A. I.; Zedgenizov, V. G.; Ovchinnikova, N. I.

2017-10-01

The purpose of the paper is to analyze the dynamics of the braking of the wheel under normal load variations. The paper uses a mathematical simulation method according to which the calculation model of an object as a mechanical system is associated with a dynamically equivalent schematic structure of the automatic control. Transfer function tool analyzing structural and technical characteristics of an object as well as force disturbances were used. It was proved that the analysis of dynamic characteristics of the wheel subjected to external force disturbances has to take into account amplitude and phase-frequency characteristics. Normal load variations impact car wheel braking subjected to disturbances. The closer slip to the critical point is, the higher the impact is. In the super-critical area, load variations cause fast wheel blocking.

Profound Effect of Profiling Platform and Normalization Strategy on Detection of Differentially Expressed MicroRNAs – A Comparative Study

Science.gov (United States)

Meyer, Swanhild U.; Kaiser, Sebastian; Wagner, Carola; Thirion, Christian; Pfaffl, Michael W.

2012-01-01

Background Adequate normalization minimizes the effects of systematic technical variations and is a prerequisite for getting meaningful biological changes. However, there is inconsistency about miRNA normalization performances and recommendations. Thus, we investigated the impact of seven different normalization methods (reference gene index, global geometric mean, quantile, invariant selection, loess, loessM, and generalized procrustes analysis) on intra- and inter-platform performance of two distinct and commonly used miRNA profiling platforms. Methodology/Principal Findings We included data from miRNA profiling analyses derived from a hybridization-based platform (Agilent Technologies) and an RT-qPCR platform (Applied Biosystems). Furthermore, we validated a subset of miRNAs by individual RT-qPCR assays. Our analyses incorporated data from the effect of differentiation and tumor necrosis factor alpha treatment on primary human skeletal muscle cells and a murine skeletal muscle cell line. Distinct normalization methods differed in their impact on (i) standard deviations, (ii) the area under the receiver operating characteristic (ROC) curve, (iii) the similarity of differential expression. Loess, loessM, and quantile analysis were most effective in minimizing standard deviations on the Agilent and TLDA platform. Moreover, loess, loessM, invariant selection and generalized procrustes analysis increased the area under the ROC curve, a measure for the statistical performance of a test. The Jaccard index revealed that inter-platform concordance of differential expression tended to be increased by loess, loessM, quantile, and GPA normalization of AGL and TLDA data as well as RGI normalization of TLDA data. Conclusions/Significance We recommend the application of loess, or loessM, and GPA normalization for miRNA Agilent arrays and qPCR cards as these normalization approaches showed to (i) effectively reduce standard deviations, (ii) increase sensitivity and accuracy of

Closed-form confidence intervals for functions of the normal mean and standard deviation.

Science.gov (United States)

Donner, Allan; Zou, G Y

2012-08-01

Confidence interval methods for a normal mean and standard deviation are well known and simple to apply. However, the same cannot be said for important functions of these parameters. These functions include the normal distribution percentiles, the Bland-Altman limits of agreement, the coefficient of variation and Cohen's effect size. We present a simple approach to this problem by using variance estimates recovered from confidence limits computed for the mean and standard deviation separately. All resulting confidence intervals have closed forms. Simulation results demonstrate that this approach performs very well for limits of agreement, coefficients of variation and their differences.

Masturbation, sexuality, and adaptation: normalization in adolescence.

Science.gov (United States)

Shapiro, Theodore

2008-03-01

During adolescence the central masturbation fantasy that is formulated during childhood takes its final form and paradoxically must now be directed outward for appropriate object finding and pair matching in the service of procreative aims. This is a step in adaptation that requires a further developmental landmark that I have called normalization. The path toward airing these private fantasies is facilitated by chumship relationships as a step toward further exposure to the social surround. Hartmann's structuring application of adaptation within psychoanalysis is used as a framework for understanding the process that simultaneously serves intrapsychic and social demands and permits goals that follow evolutionary principles. Variations in the normalization process from masturbatory isolation to a variety of forms of sexual socialization are examined in sociological data concerning current adolescent sexual behavior and in case examples that indicate some routes to normalized experience and practice.

Inter-laboratory variation in DNA damage using a standard comet assay protocol

DEFF Research Database (Denmark)

Forchhammer, Lykke; Ersson, Clara; Loft, Steffen

2012-01-01

determined the baseline level of DNA strand breaks (SBs)/alkaline labile sites and formamidopyrimidine DNA glycosylase (FPG)-sensitive sites in coded samples of mononuclear blood cells (MNBCs) from healthy volunteers. There were technical problems in seven laboratories in adopting the standard protocol...... analysed by the standard protocol. The SBs and FPG-sensitive sites were measured in the same experiment, indicating that the large spread in the latter lesions was the main reason for the reduced inter-laboratory variation. However, it remains worrying that half of the participating laboratories obtained...

Standardized uptake values of fluorine-18 fluorodeoxyglucose: the value of different normalization procedures

International Nuclear Information System (INIS)

Schomburg, A.; Bender, H.; Reichel, C.; Sommer, T.; Ruhlmann, J.; Kozak, B.; Biersack, H.J.

1996-01-01

While the evident advantages of absolute metabolic rate determinations cannot be equalled by static image analysis of fluorine-18 fluorodexyglucose positron emission tomographic (FDG PET) studies, various algorithms for the normalization of static FDG uptake values have been proposed. This study was performed to compare different normalization procedures in terms of dependency on individual patient characteristics. Standardized FDG uptake values (SUVs) were calculated for liver and lung tissue in 126 patients studied with whole-body FDG PET. Uptake values were normalized for total body weight, lean body mass and body surface area. Ranges, means, medians, standard deviations and variation coefficients of these SUV parameters were calculated and their interdependency with total body weight, lean body mass, body surface area, patient height and blood sugar levels was calculated by means of regression analysis. Standardized FDG uptake values normalized for body surface area were clearly superior to SUV parameters normalized for total body weight or lean body mass. Variation and correlation coefficients of body surface area-normalized uptake values were minimal when compared with SUV parameters derived from the other normalization procedures. Normalization for total body weight resulted in uptake values still dependent on body weight and blood sugar levels, while normalization for lean body mass did not eliminate the positive correlation with lean body mass and patient height. It is concluded that normalization of FDG uptake values for body surface area is less dependent on the individual patient characteristics than are FDG uptake values normalized for other parameters, and therefore appears to be preferable for FDG PET studies in oncology. (orig.)

High and Low LET Radiation Differentially Induce Normal Tissue Damage Signals

International Nuclear Information System (INIS)

Niemantsverdriet, Maarten; Goethem, Marc-Jan van; Bron, Reinier; Hogewerf, Wytse; Brandenburg, Sytze; Langendijk, Johannes A.; Luijk, Peter van; Coppes, Robert P.

2012-01-01

Purpose: Radiotherapy using high linear energy transfer (LET) radiation is aimed at efficiently killing tumor cells while minimizing dose (biological effective) to normal tissues to prevent toxicity. It is well established that high LET radiation results in lower cell survival per absorbed dose than low LET radiation. However, whether various mechanisms involved in the development of normal tissue damage may be regulated differentially is not known. Therefore the aim of this study was to investigate whether two actions related to normal tissue toxicity, p53-induced apoptosis and expression of the profibrotic gene PAI-1 (plasminogen activator inhibitor 1), are differentially induced by high and low LET radiation. Methods and Materials: Cells were irradiated with high LET carbon ions or low LET photons. Cell survival assays were performed, profibrotic PAI-1 expression was monitored by quantitative polymerase chain reaction, and apoptosis was assayed by annexin V staining. Activation of p53 by phosphorylation at serine 315 and serine 37 was monitored by Western blotting. Transfections of plasmids expressing p53 mutated at serines 315 and 37 were used to test the requirement of these residues for apoptosis and expression of PAI-1. Results: As expected, cell survival was lower and induction of apoptosis was higher in high -LET irradiated cells. Interestingly, induction of the profibrotic PAI-1 gene was similar with high and low LET radiation. In agreement with this finding, phosphorylation of p53 at serine 315 involved in PAI-1 expression was similar with high and low LET radiation, whereas phosphorylation of p53 at serine 37, involved in apoptosis induction, was much higher after high LET irradiation. Conclusions: Our results indicate that diverse mechanisms involved in the development of normal tissue damage may be differentially affected by high and low LET radiation. This may have consequences for the development and manifestation of normal tissue damage.

Impact of host cell variation on the neutralization of HIV-1 in vitro.

Science.gov (United States)

Polonis, Victoria R; Schuitemaker, Hanneke; Bunnik, Evelien M; Brown, Bruce K; Scarlatti, Gabriella

2009-09-01

In this review we present current advances in our understanding of HIV-1 neutralization assays that employ primary cell types, as compared with those that utilize cell lines and the newer, more standardized pseudovirus assays. A commentary on the challenges of standardizing in-vitro neutralization assays using primary cells is included. The data from reporter cell line neutralization assays may agree with results observed in primary cells; however, exceptions have recently been reported. Multiple variables exist in primary cell assays using peripheral blood mononuclear cells from HIV-seronegative donors; in-vitro neutralization titers can vary significantly based on the donor cells used for assay targets and for virus propagation. Thus, more research is required to achieve validated primary cell neutralization assays. HIV-vaccine-induced antibody performance in the current neutralization assays may function as a 'gatekeeper' for HIV-1 subunit vaccine advancement. Development of standardized platforms for reproducible measurement of in-vitro neutralization is therefore a high priority. Given the considerable variation in results obtained from some widely applied HIV neutralization platforms, parallel evaluation of new antibodies using different host cells for assay targets, as well as virus propagation, is recommended until immune correlates of protection are identified.

Limit theorems for power variations of ambit fields driven by white noise

DEFF Research Database (Denmark)

Pakkanen, Mikko

We study the asymptotic behavior of lattice power variations of two-parameter ambit fields that are driven by white noise. Our first result is a law of large numbers for such power variations. Under a constraint on the memory of the ambit field, normalized power variations are shown to converge...

Diurnal levels of immunoreactive erythropoietin in normal subjects and subjects with chronic lung disease

Energy Technology Data Exchange (ETDEWEB)

Miller, M.E.; Garcia, J.F.; Cohen, R.A.; Cronkite, E.P.; Moccia, G.; Acevedo, J.

1981-10-01

Serum levels of immunoreactive erythropoietin (Ep) were measured in 48 normal male and female volunteers, ages 20-60 years, to establish a control value for Ep of 18.5 +/- 5.0 (mean +/- SD) mU/ml. Levels of the hormone were also measured sequentially over a 24 h period of time in an additional 17 normal volunteers with no diurnal variation. Diurnal levels of immunoreactive Ep were also measured in 30 subjects, with chronic lung disease. These patients, in contrast to normal subjects exhibited a diurnal variation in the level of immunoreactive Ep with peak levels occurring at midnight. The only variable measured which correlated with the serum immunoreactive Ep level in subjects with chronic lung disease was the level of carboxyhaemoglobin (P less than 0.02).

Two new automated, compared with two enzyme-linked immunosorbent, antimüllerian hormone assays.

Science.gov (United States)

Nelson, Scott M; Pastuszek, Ewa; Kloss, Grzegorz; Malinowska, Iwona; Liss, Joanna; Lukaszuk, Aron; Plociennik, Lukasz; Lukaszuk, Krzysztof

2015-10-01

To compare new automated antimüllerian hormone (AMH) assay performance characteristics from the new automated Elecsys AMH (Roche; Elecsys) and Access AMH (Beckman Coulter; Access) assays with the existing AMH Gen II ELISA (enzyme-linked immunosorbent assay; Gen II; Beckman Coulter) and AMH ELISA (Ansh Labs) assays. Prospective assay evaluation. University-affiliated clinical chemistry laboratory. Patients referred for serum AMH measurement (n = 83) before start of in vitro fertilization cycle between September 2014 and October 2014. None. Serum AMH concentration. Intra-assay coefficients of variation were low; Ansh ≤ 9.0%; Gen II ≤ 5.8%; Access ≤ 10.7%; and Elecsys ≤ 2.8%. The Passing-Bablok regression equations (pmol/L) were y (Access) = 0.128 + (0.781 × Gen II); and y (Access) = 0.302 + (0.742 x Ansh). For y (Elecys) = 0.087 + (0.729 x Gen II) and y (Elecys) = 0.253 + (0.688 x Ansh Labs). For y (Elecys) = 0.943 - (0.037 × Access). For all the assays, AMH exhibited a moderate positive correlation with AFC (r = 0.62-0.64); number of cumulus oocyte complexes (r = 0.60-0.64); and metaphase II oocytes (r = 0.48-0.50). Accuracy of pregnancy prediction, as determined by area under the receiver operating characteristic curve, was uniformly low for all assays (0.62-0.63). The novel automated assays exhibit strong concordance in calibration, but derived values are substantially lower than those obtained from pre-existing assays, with assay-specific interpretation required for routine clinical use. These results highlight the need for an international standard of measurement of AMH. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Dynamic optical tweezers based assay for monitoring early drug resistance

International Nuclear Information System (INIS)

Wu, Xiaojing; Zhu, Siwei; Feng, Jie; Zhang, Yuquan; Min, Changjun; Yuan, X-C

2013-01-01

In this letter, a dynamic optical tweezers based assay is proposed and investigated for monitoring early drug resistance with Pemetrexed-resistant non-small cell lung cancer (NSCLC) cell lines. The validity and stability of the method are verified experimentally in terms of the physical parameters of the optical tweezers system. The results demonstrate that the proposed technique is more convenient and faster than traditional techniques when the capability of detecting small variations of the response of cells to a drug is maintained. (letter)

An immunoradiometric assay for procoagulant factor VIII antigen: results in haemophilia, von Willebrand's disease and fetal plasma and serum

International Nuclear Information System (INIS)

Peake, I.R.; Bloom, A.L.; Giddings, J.C.; Ludlam, C.A.

1979-01-01

An immunoradiometric assay (IRMA) has been developed based on the inhibitor which arose in a polytransfused severe haemophiliac. The two-site IRMA measured antigens closely associated with the procoagulant parts of the factor VIII complex, which are termed FVIIIC antigens or FVIIICAG. FVIIICAG was present in normal plasma and also, at a slightly lower concentration, in normal serum. In 37 patients with haemophilia A, 36 had FVIIICAG levels of less than 10% of the normal plasma pool. In patients with von Willebrand's disease the levels of FVIIIC and FVIIICAG were in good agreement, both before and after treatment with cryoprecipitate or DDAVP. FVIIICAG was relatively stable in plasma at 37 0 C and could also be detected in cord and fetal serum. The assay is of potential value for detecting reduced levels of factor VIII, for carrier detection and for the prenatal diagnosis of haemophilia. (author)

The clinical importance of the anatomic variations in the paranasal sinuses

International Nuclear Information System (INIS)

Teixeira Junior, Francisco Ribeiro; Bretas, Elisa Almeida Sathler; Madeira, Ivana Andrade; Diniz, Renata Furletti; Ribeiro, Marcelo Almeida; Motta, Emilia Guerra Pinto Coelho; Moreira, Wanderval

2008-01-01

The anatomic variations of the paranasal sinuses are common findings. The importance of such variations predisposing disease through the obstruction of the drainage pathway has been discussed by several authors, although it is not yet a matter of agreement. The literature was reviewed and a iconographic assay was prepared aiming the discussion of the importance of the main anatomic variations of the paranasal sinuses. The prevalence of anatomic variations of the paranasal sinuses varies largely amongst studies and its role in sinus disease is controversial. In this article, it is described the different variations associated to paranasal disease and how they relate to pathologic conditions. Most studies confirm the concept that anatomic variations of the paranasal sinuses are related to disease when they obstruct the drainage pathways. The knowledge of such alterations and its relations to pathologic conditions is expected from the general radiologist. (author)

Microbead agglutination based assays

KAUST Repository

Kodzius, Rimantas

2013-01-21

We report a simple and rapid room temperature assay for point-of-care (POC) testing that is based on specific agglutination. Agglutination tests are based on aggregation of microbeads in the presence of a specific analyte thus enabling the macroscopic observation. Such tests are most often used to explore antibody-antigen reactions. Agglutination has been used for protein assays using a biotin/streptavidin system as well as a hybridization based assay. The agglutination systems are prone to selftermination of the linking analyte, prone to active site saturation and loss of agglomeration at high analyte concentrations. We investigated the molecular target/ligand interaction, explaining the common agglutination problems related to analyte self-termination, linkage of the analyte to the same bead instead of different microbeads. We classified the agglutination process into three kinds of assays: a two- component assay, a three-component assay and a stepped three- component assay. Although we compared these three kinds of assays for recognizing DNA and protein molecules, the assay can be used for virtually any molecule, including ions and metabolites. In total, the optimized assay permits detecting analytes with high sensitivity in a short time, 5 min, at room temperature. Such a system is appropriate for POC testing.

The thoracic paraspinal shadow: normal appearances.

Science.gov (United States)

Lien, H H; Kolbenstvedt, A

1982-01-01

The width of the right and left thoracic paraspinal shadows were measured at all levels in 200 presumably normal individuals. The paraspinal shadow could be identified in nearly all cases on the left side and in approximately one-third on the right. The range of variation was greater on the left side than one the right. The left paraspinal shadow was wider at the upper levels and in individuals above 40 years of age.

Similarity criterion analysis of dose-response curves in biological assay and radioimmunoassay of hormones

International Nuclear Information System (INIS)

Cristakou, H.D.

1983-01-01

The difficulties involved in the control of biological and radioimmunological assay systems, and in the maintenance of standard, as well as, the usual heterogeneity of assayed samples require some evidence of similarity between the dose-response curves obtained with the standard and the sample. Nowadays the parallelism test is used to provide such evidence. However, some indications of non-normal errors distribution, such as the presence of out layers, render the parallelism test both conceptually implausible and statistically inefficient. In such a manner we suggest the non-parametric 'frequencial' test as a more sounding option. (author)

Modeling of coupled differential equations for cellular chemical signaling pathways: Implications for assay protocols utilized in cellular engineering.

Science.gov (United States)

O'Clock, George D

2016-08-01

Cellular engineering involves modification and control of cell properties, and requires an understanding of fundamentals and mechanisms of action for cellular derived product development. One of the keys to success in cellular engineering involves the quality and validity of results obtained from cell chemical signaling pathway assays. The accuracy of the assay data cannot be verified or assured if the effect of positive feedback, nonlinearities, and interrelationships between cell chemical signaling pathway elements are not understood, modeled, and simulated. Nonlinearities and positive feedback in the cell chemical signaling pathway can produce significant aberrations in assay data collection. Simulating the pathway can reveal potential instability problems that will affect assay results. A simulation, using an electrical analog for the coupled differential equations representing each segment of the pathway, provides an excellent tool for assay validation purposes. With this approach, voltages represent pathway enzyme concentrations and operational amplifier feedback resistance and input resistance values determine pathway gain and rate constants. The understanding provided by pathway modeling and simulation is strategically important in order to establish experimental controls for assay protocol structure, time frames specified between assays, and assay concentration variation limits; to ensure accuracy and reproducibility of results.

Ultra-performance liquid chromatography-tandem mass spectrometry-based multiplex enzyme assay for six enzymes associated with hereditary hemolytic anemia.

Science.gov (United States)

Park, Chul Min; Lee, Kyunghoon; Jun, Sun-Hee; Song, Sang Hoon; Song, Junghan

2017-08-15

Deficiencies in erythrocyte metabolic enzymes are associated with hereditary hemolytic anemia. Here, we report the development of a novel multiplex enzyme assay for six major enzymes, namely glucose-6-phosphate dehydrogenase, pyruvate kinase, pyrimidine 5'-nucleotidase, hexokinase, triosephosphate isomerase, and adenosine deaminase, deficiencies in which are implicated in erythrocyte enzymopathies. To overcome the drawbacks of traditional spectrophotometric enzyme assays, the present assay was based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The products of the six enzymes were directly measured by using ion pairing UPLC-MS/MS, and the precision, linearity, ion suppression, optimal sample amounts, and incubation times were evaluated. Eighty-three normal individuals and 13 patients with suspected enzymopathy were analyzed. The UPLC running time was within 5min. No ion suppression was observed at the retention time for the products or internal standards. We selected an optimal dilution factor and incubation time for each enzyme system. The intra- and inter-assay imprecision values (CVs) were 2.5-12.1% and 2.9-14.3%, respectively. The linearity of each system was good, with R 2 values >0.97. Patient samples showed consistently lower enzyme activities than those from normal individuals. The present ion paring UPLC-MS/MS assay enables facile and reproducible multiplex evaluation of the activity of enzymes implicated in enzymopathy-associated hemolytic anemia. Copyright © 2017 Elsevier B.V. All rights reserved.

ASTRO Research Fellow Presentation - A comparison of the comet assay and pulsed-field gel electrophoresis as a predictive assay for radiosensitivity in human fibroblasts

International Nuclear Information System (INIS)

Sarkaria, Jann N.; Eady, John J.; Peacock, John H.; Steel, G. Gordon

1996-01-01

Purpose/Objective: To determine whether neutral lysis single-cell gel electrophoresis (comet assay) or pulsed-field gel electrophoresis (PFGE) can be used as a predictive assay for tissue response to radiotherapy as an alternative to clonogenic survival measurements. Materials and Methods: The comet assay has been widely used to measure DNA double strand breaks (dsb) in individual cells, and it has been suggested that it could be used as an alternative to clonogenic assays to measure radiosensitivity. Previous studies in this lab have demonstrated the ability of pulsed-field gel electrophoresis, which also measures DNA dsb, to accurately predict the radiosensitivity of a panel of fibroblasts based on determination of residual DNA dsb. As part of an ongoing study examining the relationship between fibroblast radiosensitivity and normal-tissue radiation reactions, we have compared the sensitivity and accuracy of the comet assay and PFGE on a different panel of non-transformed fibroblasts derived from breast cancer patients who developed severe radiation late effects and from case-matched controls. For the measurement of initial damage, cells were suspended in PBS and irradiated on ice for the comet assay and irradiated in agarose plugs on ice for pFGE. Residual damage was measured following irradiation of confluent cultures at 37 degree sign C and subsequent incubation for four hours prior to preparation of agarose slides and plugs. All irradiations were performed with a 59 TBq 60 Co source at a dose rate of 1.7 Gy/min. Electrophoresis was performed following neutral pH cell lysis. Comet images were captured and analyzed using Optimas software with DNA damage quantitated by the comet moment. PFGE gels were analyzed using a phosphor-image analysis system and damage was quantitated based on the percent of activity released from the well. Results: The comet assay was able to detect initial DNA damage at a threshold of 5 Gy and exhibited a linear dose

Propagation of normal zones in composite superconductors

International Nuclear Information System (INIS)

Dresner, L.

1976-08-01

This paper describes calculations of propagation velocities of normal zones in composite superconductors. Full accounting is made for (1) current sharing, (2) the variation with temperature of the thermal conductivity of the copper matrix, and the specific heats of the matrix and the superconductor, and (3) the variation with temperature of the steady-state heat transfer at a copper-helium interface in the nucleate-boiling, transition, and film-boiling ranges. The theory, which contains no adjustable parameters, is compared with experiments on bare (uninsulated) conductors. Agreement is not good. It is concluded that the effects of transient heat transfer may need to be included in the theory to improve agreement with experiment

Development of a rapid, simple assay of plasma total carotenoids

Science.gov (United States)

2012-01-01

Background Plasma total carotenoids can be used as an indicator of risk of chronic disease. Laboratory analysis of individual carotenoids by high performance liquid chromatography (HPLC) is time consuming, expensive, and not amenable to use beyond a research laboratory. The aim of this research is to establish a rapid, simple, and inexpensive spectrophotometric assay of plasma total carotenoids that has a very strong correlation with HPLC carotenoid profile analysis. Results Plasma total carotenoids from 29 volunteers ranged in concentration from 1.2 to 7.4 μM, as analyzed by HPLC. A linear correlation was found between the absorbance at 448 nm of an alcohol / heptane extract of the plasma and plasma total carotenoids analyzed by HPLC, with a Pearson correlation coefficient of 0.989. The average coefficient of variation for the spectrophotometric assay was 6.5% for the plasma samples. The limit of detection was about 0.3 μM and was linear up to about 34 μM without dilution. Correlations between the integrals of the absorption spectra in the range of carotenoid absorption and total plasma carotenoid concentration gave similar results to the absorbance correlation. Spectrophotometric assay results also agreed with the calculated expected absorbance based on published extinction coefficients for the individual carotenoids, with a Pearson correlation coefficient of 0.988. Conclusion The spectrophotometric assay of total carotenoids strongly correlated with HPLC analysis of carotenoids of the same plasma samples and expected absorbance values based on extinction coefficients. This rapid, simple, inexpensive assay, when coupled with the carotenoid health index, may be useful for nutrition intervention studies, population cohort studies, and public health interventions. PMID:23006902

A novel assay to diagnose hereditary angioedema utilizing inhibition of bradykinin-forming enzymes

DEFF Research Database (Denmark)

Joseph, Kusumam; Bains, Sonia; Tholanikunnel, Baby G

2015-01-01

. This was evident regardless whether we measured factor XIIa-C1-INH or kallikrein-C1-INH complexes, and the two assays were in close agreement. By contrast, testing the same samples utilizing the commercial method (complex ELISA, Quidel Corp.) revealed levels of C1-INH between 0 and 57% of normal (mean, 38%) and 42...

Evaluation of hemoglobin A1c measurement from filter paper using high-performance liquid chromatography and immunoturbidimetric assay.

Science.gov (United States)

Wu, Yonghua; Yang, Xu; Wang, Haining; Li, Zhenrong; Wang, Tiancheng

2017-04-01

Glycated hemoglobin (HbA 1c ) measurement from whole blood (WB) samples is inconvenient for epidemic surveillance and self-monitoring of glycemic level. We evaluated HbA 1c measurement from WB blotted on filter paper (FP), which can be easily transported to central laboratories, with high-performance liquid chromatography (HPLC) and immunoturbidimetric assay (ITA). WB was applied to Whatman filter paper. By using HPLC and WB samples as reference methods, these FP samples were evaluated on HPLC and ITA. Inter- and intra-assay variation, WB vs. FP agreement and sample stability at 20-25 °C and -70 °C were assessed by statistical analysis. Results showed that the coefficient of variation (CV, %) of FP samples for HPLC and ITA were 0.44-1.02% and 1.47-2.72%, respectively (intra-assay); 2.13-3.56% and 3.21-4.82%, respectively (inter-assay). The correlation of WB HPLC with FP analyzed using HPLC and ITA are both significant (p < 0.001). Sample stability showed that FP method up to 5 days at 20-25 °C and 5 weeks at -70 °C is accurate and reproducible. In conclusion, FP samples analyzed by HPLC and ITA can both provide an alternative to WB for HbA 1c measurement, supporting the use of FP method in epidemic surveillance and healthcare units.

A New Modified Histogram Matching Normalization for Time Series Microarray Analysis.

Science.gov (United States)

Astola, Laura; Molenaar, Jaap

2014-07-01

Microarray data is often utilized in inferring regulatory networks. Quantile normalization (QN) is a popular method to reduce array-to-array variation. We show that in the context of time series measurements QN may not be the best choice for this task, especially not if the inference is based on continuous time ODE model. We propose an alternative normalization method that is better suited for network inference from time series data.

Marrow stem cell release in the autorepopulation assay

Energy Technology Data Exchange (ETDEWEB)

Maloney, M A; Patt, H M [California Univ., San Francisco (USA). Lab. of Radiobiology

1978-01-01

The early migration of stem cells from shielded marrow to an irradiated spleen has been re-evaluated, and the findings have been compared with the results of earlier studies. The composite data reveal a constant rate during the first 24 h after irradiation, with a slope of 1.6 cells per h and an intercept of 2.4. The positive intercept is interpreted to signify an immediate brief perturbation of CFU/sub s/ release. The low concentration of CFU/sub s/ in the bloodstream, despite their continuous migration from the shielded marrow, is indicative of a rapid, and probably greatly increased, blood turnover. Despite the constancy of stem cell seeding, it is not yet possible to determine whether the rate of stem cell release is different in shielded marrow than in normal marrow. The resolution of this question requires more precise information about spleen seeding efficiency in the autorepopulation assay and about the normal turnover rate of stem cells in the bloodstream.

Generation of hiPSTZ16 (ISMMSi003-A cell line from normal human foreskin fibroblasts

Directory of Open Access Journals (Sweden)

Marion Dejosez

2018-01-01

Full Text Available Human foreskin fibroblasts from a commercial source were reprogrammed into induced pluripotent stem cells to establish a clonal stem cell line, hiPSTZ16 (ISMMSi003-A. These cells show a normal karyotype and full differentiation potential in teratoma assays. The described cells provide a useful resource in combination with other iPS cell lines generated from normal human foreskin fibroblasts to study source- and reprogramming method-independent effects in downstream applications.

The optimal condition of performing MTT assay for the determination of radiation sensitivity

International Nuclear Information System (INIS)

Hong, Semie; Kim, Il Han

2001-01-01

The measurement of radiation survival using a clonogenic assay, the established standard, can be difficult and time consuming. In this study, We have used the MTT assay, based on the reduction of a tetrazolium salt to a purple formazan precipitate by living cells, as a substitution for clonogenic assay and have examined the optimal condition for performing this assay in determination of radiation sensitivity. Four human cancer cell lines - PCI-1, SNU-1066, NCI-H63O and RKO cells have been used. For each cell line, a clonogenic assay and a MTT assay using Premix WST-1 solution, which is one of the tetrazolium salts and does not require washing or solubilization of the precipitate were carried out after irradiation of 0, 2, 4, 6, 8, 10 Gy, For clonogenic assay, cells in 25 cm 2 flasks were irradiated after overnight incubation and the resultant colonies containing more than 50 cells were scored after culturing the cells for 10-14 days, For MTT assay, the relationship between absorbance and cell number, optimal seeding cell number, and optimal timing of assay was determined. Then, MTT assay was performed when the irradiated cells had regained exponential growth or when the non-irradiated cells had undergone four or more doubling times. There was minimal variation in the values gained from these two methods with the standard deviation generally less than 5%, and there were no statistically significant differences between two methods according to t-test in low radiation dose (below 6 Gy). The regression analyses showed high linear correlation with the R 2 value of 0.975-0.992 between data from the two different methods. The optimal cell numbers for MTT assay were found to be dependent on plating efficiency of used cell line. Less than 300 cells/well were appropriate for cells with high plating efficiency (more than 30%). For cells with low plating efficiency (less than 30%), 500 cells/well or more were appropriate for assay. The optimal time for MTT assay was alter 6

Evaluation of Different Estimation Methods for Accuracy and Precision in Biological Assay Validation.

Science.gov (United States)

Yu, Binbing; Yang, Harry

2017-01-01

Biological assays ( bioassays ) are procedures to estimate the potency of a substance by studying its effects on living organisms, tissues, and cells. Bioassays are essential tools for gaining insight into biologic systems and processes including, for example, the development of new drugs and monitoring environmental pollutants. Two of the most important parameters of bioassay performance are relative accuracy (bias) and precision. Although general strategies and formulas are provided in USP, a comprehensive understanding of the definitions of bias and precision remain elusive. Additionally, whether there is a beneficial use of data transformation in estimating intermediate precision remains unclear. Finally, there are various statistical estimation methods available that often pose a dilemma for the analyst who must choose the most appropriate method. To address these issues, we provide both a rigorous definition of bias and precision as well as three alternative methods for calculating relative standard deviation (RSD). All methods perform similarly when the RSD ≤10%. However, the USP estimates result in larger bias and root-mean-square error (RMSE) compared to the three proposed methods when the actual variation was large. Therefore, the USP method should not be used for routine analysis. For data with moderate skewness and deviation from normality, the estimates based on the original scale perform well. The original scale method is preferred, and the method based on log-transformation may be used for noticeably skewed data. LAY ABSTRACT: Biological assays, or bioassays, are essential in the development and manufacture of biopharmaceutical products for potency testing and quality monitoring. Two important parameters of assay performance are relative accuracy (bias) and precision. The definitions of bias and precision in USP 〈1033〉 are elusive and confusing. Another complicating issue is whether log-transformation should be used for calculating the

Limitations of the radioimmunoprecipitation polyethylene glycol assay (RIPEGA) for detection of filarial antigens in serum

International Nuclear Information System (INIS)

Hamilton, R.G.; Alexander, E.; Adkinson, N.F.

1984-01-01

The performance of the radioimmunoprecipitation polyethylene glycol assay (RIPEGA) was examined for quantitation of filarial antigens (Brugia malayi and Dirofilaria immitis) in serum from infected human and animal hosts and non-infected controls. Multiple PEG concentrations were employed to determine the level of non-specific binding (NSB) in non-exposed human sera (NEHS) containing no filarial antigen. The NSB observed when 3 different 125 I-labelled IgG antibodies were added to 26 NEHS varied 3-fold and was correlated significantly with total serum IgM (r = 0.80, P 2 fragment of the 125 I-labelled antibody was used, but the correlation of NSB with total serum IgM remained significant (r = 0.57, P < 0.01). The presence of rheumatoid factor in NEHS sera also significantly increased NSB by an average of 3-fold. These effects eliminated the assay's ability to detect in sera from infected hosts filarial antigen the presence of which could be readily demonstrated by an immunoradiometric assay. The RIPEGA's precision (intra-assay coefficient of variation (CV) = 21% at 35% Bsub(max)) and reproducibility (inter-assay CV = 29% at 35% Bsub(max)) are less satisfactory than many alternative immunoassays. (Auth.)

New fluorimetric assay of horseradish peroxidase using sesamol as substrate and its application to EIA

Directory of Open Access Journals (Sweden)

Hidetoshi Arakawa

2012-04-01

Full Text Available Horseradish peroxidase (HRP is generally used as a label enzyme in enzyme immunoassay (EIA. The procedure used for HRP detection in EIA is critical for sensitivity and precision. This paper describes a novel fluorimetric assay for horseradish peroxidase (HRP using sesamol as substrate. The principle of the assay is as follow: sesamol (3,4-methylenedioxy phenol is reacted enzymatically in the presence of hydrogen peroxide to produce dimeric sesamol. The dimer is fluorescent and can be detected sensitively at ex. 347 nm, em. 427 nm.The measurable range of HRP was 1.0×10−18 to 1.0×10−15 mol/assay, with a detection limit of 1.0×10−18 mol/assay. The coefficient of variation (CV, n=8 was examined at each point on the standard curve, with a mean CV percentage of 3.8%. This assay system was applied to thyroid stimulating hormone (TSH EIA using HRP as the label enzyme. Keywords: Sesamol, Fluorescence, Enzyme immunoassay (EIA, Horseradish peroxidase (HRP, Thyroid stimulating hormone (TSH

Vertebral artery terminating in posterior inferior cerebellar artery: A normal variation with clinical significance.

Directory of Open Access Journals (Sweden)

I-Wen Liu

Full Text Available A vertebral artery (VA terminating in a posterior inferior cerebellar artery (PICA is often considered to be a normal variation associated with VA hypoplasia. We aimed to investigate the clinical significance of this cerebrovascular variant. A total of 80 patients with clinically evident cerebrovascular events in posterior circulation were examined by duplex sonography and magnetic resonance angiography (MRA. Eighty healthy subjects who had MRA check-up were recruited as controls. PICA termination of the VA (PICA-VA was identified as the VA not communicating with the basilar artery (BA but ending into a PICA. We compared the prevalence of PICA-VA and associated hemodynamic parameters between the patients with and without PICA-VA, and investigated their relationships with VA hypoplasia. The prevalence of PICA-VA was higher in the patient group than in the controls (18.7% vs. 6.3%, p = 0.015. Most measurements (73.3% of PICA-VA did not fit the criteria of VA hypoplasia. In comparison with the non-PICA-terminating group, the PICA-VA has a smaller diameter (3.7 ± 0.7 mm vs. 3.0 ± 0.5 mm, p < 0.001, lower mean velocity (241 ± 100 mm/sec vs. 164 ± 88 mm/sec, p < 0.01, and higher pulsatility index (1.3 ± 0.5 vs. 1.9 ± 0.6, p < 0.001. Moreover, a smaller diameter of the BA (3.2 ± 0.5 mm vs. 2.5 ± 0.9 mm, p = 0.004 and the posterior cerebral artery (PCA (2.0 ± 0.1 mm vs. 1.6 ± 0.1 mm, p = 0.006 were also noted in the PICA-VA group. The higher prevalence of PICA-VA in the patient group with smaller diameter of VA, BA and PCA reflected its clinical significance, suggesting that PICA-VA may have a detrimental impact on cerebral hemodynamics. However, the sample is small, and further studies are needed with larger sample size for confirmation.

Identification of valid reference genes for the normalization of RT qPCR gene expression data in human brain tissue

Directory of Open Access Journals (Sweden)

Ravid Rivka

2008-05-01

Full Text Available Abstract Background Studies of gene expression in post mortem human brain can contribute to understanding of the pathophysiology of neurodegenerative diseases, including Alzheimer's disease (AD, Parkinson's disease (PD and dementia with Lewy bodies (DLB. Quantitative real-time PCR (RT qPCR is often used to analyse gene expression. The validity of results obtained using RT qPCR is reliant on accurate data normalization. Reference genes are generally used to normalize RT qPCR data. Given that expression of some commonly used reference genes is altered in certain conditions, this study aimed to establish which reference genes were stably expressed in post mortem brain tissue from individuals with AD, PD or DLB. Results The present study investigated the expression stability of 8 candidate reference genes, (ubiquitin C [UBC], tyrosine-3-monooxygenase [YWHAZ], RNA polymerase II polypeptide [RP II], hydroxymethylbilane synthase [HMBS], TATA box binding protein [TBP], β-2-microglobulin [B2M], glyceraldehyde-3-phosphate dehydrogenase [GAPDH], and succinate dehydrogenase complex-subunit A, [SDHA] in cerebellum and medial temporal gyrus of 6 AD, 6 PD, 6 DLB subjects, along with 5 matched controls using RT qPCR (TaqMan® Gene Expression Assays. Gene expression stability was analysed using geNorm to rank the candidate genes in order of decreasing stability in each disease group. The optimal number of genes recommended for accurate data normalization in each disease state was determined by pairwise variation analysis. Conclusion This study identified validated sets of mRNAs which would be appropriate for the normalization of RT qPCR data when studying gene expression in brain tissue of AD, PD, DLB and control subjects.

Measurement of cetuximab and panitumumab-unbound serum EGFR extracellular domain using an assay based on slow off-rate modified aptamer (SOMAmer reagents.

Directory of Open Access Journals (Sweden)

Noh Jin Park

Full Text Available Response to cetuximab (Erbitux® and panitumumab (Vectibix® varies among individuals, and even those who show response ultimately gain drug resistance. One possible etiologic factor is differential interaction between the drug and target. We describe the development of an assay based on Slow Off-rate Modified Aptamer (SOMAmer(™ reagents that can distinguish drug-bound from unbound epidermal growth factor receptor (EGFR.This quantitative assay uses a SOMAmer reagent specific for EGFR extracellular domain (ECD as a capturing reagent. Captured SOMAmer is quantitated using PCR. Linearity and accuracy (recovery of the assay were assessed using normal sera and purified EGFR ECD.This EGFR ECD assay showed linearity between 2.5 and 600 ng/mL. Average recovery was 101%. The assay detected EGFR but showed little cross-reactivity to other ErbB proteins: 0.4% for ErbB2, 6.9% for ErbB3, and 1.3% for ErbB4. Preincubation of normal serum with either cetuximab or panitumumab resulted in a dose-dependent decrease in EGFR ECD levels measured using the SOMAmer assay; preincubation did not affect measurement with an ELISA.This SOMAmer-based serum EGFR ECD assay accurately and specifically measures EGFR in serum. Detection of significant amounts of drug-unbound EGFR in patients undergoing cetuximab or panitumumab treatment could be an indicator of poor drug response. Further studies are needed to evaluate the utility of the assay as an indicator of drug efficacy or as a guide to dosing.

Evaluation of the DCA Vantage analyzer for HbA 1c assay.

Science.gov (United States)

Szymezak, Jean; Leroy, Nathalie; Lavalard, Emmanuelle; Gillery, Philippe

2008-01-01

Measurement of HbA 1c is key in monitoring diabetic patients in both laboratories and clinical units, where HbA 1c results are used as part of patient education. We have evaluated the DCA Vantage, a new device for immunological assay of HbA 1c. HbA 1c results obtained were evaluated in terms of precision, linearity, specificity and practicability, and were compared with results obtained by a Variant II HPLC method. The method exhibited intra- and inter-assay coefficients of variation lower than 2.6% and 4.0%, respectively, and good correlation with the comparison HPLC method (r2=0.9776). No interference was noted in the presence of labile HbA 1c or carbamylated hemoglobin. The new device exhibited improved practicability characteristics and allowed better sample identification, better management of quality control routines and greater connectivity possibilities compared to the previous DCA 2000 analyzer. This new analyzer exhibited analytical and practical characteristics very suitable for HbA 1c assay for laboratory or point-of-care use according to good laboratory practice.

Fibroblast radiosensitivity versus acute and late normal skin responses in patients treated for breast cancer

International Nuclear Information System (INIS)

Brock, William A.; Tucker, Susan L.; Geara, Fady B.; Wike, Jennifer; Peters, Lester J.; Turesson, Ingela; Nyman, Jan

1995-01-01

Purpose/Objective: To determine if the radiosensitivity of normal human skin fibroblasts, measured in early passage cultures, is significantly correlated with the degree of acute or late normal skin damage in patients treated for breast cancer with radiotherapy. Methods and Materials: In the 1970s, a series of breast cancer patients was treated at the Department of Oncology in Gothenburg, Sweden with postoperative irradiation to the parasternal region. Patients were treated bilaterally using different fractionation schedules and doses to the right and left fields. Peak acute reactions were scored on a six-point scale, and skin erythema was measured by reflectance spectrophotometry. Telangiectasia was graded over time on a six-point scale. In April 1992, two small skin biopsies were obtained from 22 patients in two treatment groups (i.e., four dose-fractionation schedules) and, using either delayed or immediate plating, fibroblast radiosensitivity was measured in early passage cultures by clonogenic survival, after high and low dose-rate irradiations. Survival at 2.0 Gy (SF2) was calculated from complete survival curves. Results: To test assay reproducibility, SF2 values derived from paired biopsies of the same patient (12 cases) were compared. A reasonably good correlation (p = 0.075) was obtained for SF2s determined by high dose-rate irradiations with immediate plating, but not for delayed plating or low dose-rate treatments. The median coefficient of variation in the replicate SF2s after high dose-rate treatment and immediate plating was 13%, suggesting that the poor correlation in paired SF2 values is due to the magnitude of the uncertainty in SF2 relative to the overall spread in SF2 values between patients (CV = 28%). Individual SF2 values and averaged values from patients with data from two biopsies were compared with the acute and late clinical reactions. A significant negative correlation was found between SF2 and relative clinical response, but only when

Observer and biological variation of a rapid whole blood D-dimer test

NARCIS (Netherlands)

Turkstra, F.; van Beek, E. J.; Büller, H. R.

1998-01-01

In consecutive patients with suspected venous thromboembolism the interobserver variability of the SimpliRED D-dimer test was evaluated by two observers who independently scored one plate, the between assay variation was performed simultaneously by a third independent observer, who assessed a second

Comparison of colorimetric assays with quantitative amino acid analysis for protein quantification of Generalized Modules for Membrane Antigens (GMMA).

Science.gov (United States)

Rossi, Omar; Maggiore, Luana; Necchi, Francesca; Koeberling, Oliver; MacLennan, Calman A; Saul, Allan; Gerke, Christiane

2015-01-01

Genetically induced outer membrane particles from Gram-negative bacteria, called Generalized Modules for Membrane Antigens (GMMA), are being investigated as vaccines. Rapid methods are required for estimating the protein content for in-process assays during production. Since GMMA are complex biological structures containing lipid and polysaccharide as well as protein, protein determinations are not necessarily straightforward. We compared protein quantification by Bradford, Lowry, and Non-Interfering assays using bovine serum albumin (BSA) as standard with quantitative amino acid (AA) analysis, the most accurate currently available method for protein quantification. The Lowry assay has the lowest inter- and intra-assay variation and gives the best linearity between protein amount and absorbance. In all three assays, the color yield (optical density per mass of protein) of GMMA was markedly different from that of BSA with a ratio of approximately 4 for the Bradford assay, and highly variable between different GMMA; and approximately 0.7 for the Lowry and Non-Interfering assays, highlighting the need for calibrating the standard used in the colorimetric assay against GMMA quantified by AA analysis. In terms of a combination of ease, reproducibility, and proportionality of protein measurement, and comparability between samples, the Lowry assay was superior to Bradford and Non-Interfering assays for GMMA quantification.

Multisite analytical evaluation of the Abbott ARCHITECT cyclosporine assay.

Science.gov (United States)

Wallemacq, Pierre; Maine, Gregory T; Berg, Keith; Rosiere, Thomas; Marquet, Pierre; Aimo, Giuseppe; Mengozzi, Giulio; Young, Julianna; Wonigeit, Kurt; Kretschmer, Robert; Wermuth, Bendicht; Schmid, Rainer W

2010-04-01

The objective of this study was to evaluate the analytical performance of the Abbott ARCHITECT Cyclosporine (CsA) immunoassay in 7 clinical laboratories in comparison to liquid chromatography/tandem mass spectrometry (LC/MS/MS), Abbott TDx, Cobas Integra 800, and the Dade Dimension Xpand immunoassay. The ARCHITECT assay uses a whole blood specimen, a pretreatment step with organic reagents to precipitate proteins and extract the drug, followed by a 2-step automated immunoassay with magnetic microparticles coated with anti-CsA antibody and an acridinium-CsA tracer. Imprecision testing at the 7 evaluation sites gave a range of total % coefficient of variations of 7.5%-12.2% at 87.5 ng/mL, 6.6%-14.3% at 411 ng/mL, and 5.2%-10.7% at 916 ng/mL. The lower limit of quantification ranged from 12 to 20 ng/mL. Purified CsA metabolites AM1, AM1c, AM4N, AM9, and AM19 were tested in whole blood by the ARCHITECT assay and showed minimal cross-reactivity at all 7 sites. In particular, AM1 and AM9 cross-reactivity in the ARCHITECT assay, ranged from -2.5% to 0.2% and -0.8% to 2.2%, respectively, and was significantly lower than for the TDx assay, in which the values were 3.2% and 16.1%, respectively. Comparable testing of metabolites in the Dade Dimension Xpand assay at 2 evaluation sites showed cross-reactivity to AM4N (6.4% and 6.8%) and AM9 (2.6% and 3.6%) and testing on the Roche Integra 800 showed cross-reactivity to AM1c (2.4%), AM9 (10.7%), and AM19 (2.8%). Cyclosporine International Proficiency Testing Scheme samples, consisting of both pooled specimens from patients receiving CsA therapy as well as whole-blood specimens supplemented with CsA, were tested by the ARCHITECT assay at 6 sites and showed an average bias of -24 to -58 ng/mL versus LC/MSMS CsA and -2 to -37 ng/mL versus AxSYM CsA. Studies were performed with the ARCHITECT CsA assay on patient specimens with the following results: ARCHITECT CsA assay versus LC/MSMS, average bias of 31 ng/mL; ARCHITECT versus the

The Dens: Normal Development, Developmental Variants and Anomalies, and Traumatic Injuries

Directory of Open Access Journals (Sweden)

William T O′Brien

2015-01-01

Full Text Available Accurate interpretation of cervical spine imagining can be challenging, especially in children and the elderly. The biomechanics of the developing pediatric spine and age-related degenerative changes predispose these patient populations to injuries centered at the craniocervical junction. In addition, congenital anomalies are common in this region, especially those associated with the axis/dens, due to its complexity in terms of development compared to other vertebral levels. The most common congenital variations of the dens include the os odontoideum and a persistent ossiculum terminale. At times, it is necessary to distinguish normal development, developmental variants, and developmental anomalies from traumatic injuries in the setting of acute traumatic injury. Key imaging features are useful to differentiate between traumatic fractures and normal or variant anatomy acutely; however, the radiologist must first have a basic understanding of the spectrum of normal developmental anatomy and its anatomic variations in order to make an accurate assessment. This review article attempts to provide the basic framework required for accurate interpretation of cervical spine imaging with a focus on the dens, specifically covering the normal development and ossification of the dens, common congenital variants and their various imaging appearances, fracture classifications, imaging appearances, and treatment options.

Detection of erbB2 copy number variations in plasma of patients with esophageal carcinoma

International Nuclear Information System (INIS)

Andolfo, Immacolata; Orditura, Michele; Ciardiello, Fortunato; De Vita, Fernando; Zollo, Massimo; Petrosino, Giuseppe; Vecchione, Loredana; De Antonellis, Pasqualino; Capasso, Mario; Montanaro, Donatella; Gemei, Marica; Troncone, Giancarlo; Iolascon, Achille

2011-01-01

Mortality is high in patients with esophageal carcinoma as tumors are rarely detected before the disease has progressed to an advanced stage. Here, we sought to isolate cell-free DNA released into the plasma of patients with esophageal carcinoma, to analyze copy number variations of marker genes in the search for early detection of tumor progression. Plasma of 41 patients with esophageal carcinoma was prospectively collected before tumor resection and chemotherapy. Our dataset resulted heterogeneous for clinical data, resembling the characteristics of the tumor. DNA from the plasma was extracted to analyze copy number variations of the erbB2 gene using real-time PCR assays. The real-time PCR assays for erbB2 gene showed significant (P = 0.001) copy number variations in the plasma of patients with esophageal carcinoma, as compared to healthy controls with high sensitivity (80%) and specificity (95%). These variations in erbB2 were negatively correlated to the progression free survival of these patients (P = 0.03), and revealed a further risk category stratification of patients with low VEGF expression levels. The copy number variation of erbB2 gene from plasma can be used as prognostic marker for early detection of patients at risk of worse clinical outcome in esophageal cancer

Development of a sensitive and specific radioreceptor assay for leukotriene B4

International Nuclear Information System (INIS)

Kohi, F.; Agrawal, D.K.; Cheng, J.B.; Bewtra, A.; Townley, R.G.; Olesch, J.W.

1988-01-01

To establish a simple and sensitive quantitation of leukotriene B 4 (LTB 4 ), they developed a radioreceptor assay (RRA) using a highly specific [ 3 H]leukotriene B 4 ([ 3 H]LTB 4 ) binding to a guinea pig spleen homogenate. The assay detected LTB 4 levels as low as 0.12 pmol per tube. 50% inhibition of bound [ 3 H]LTB 4 was obtained by 2.5 nM of unlabeled LTB 4 . [ 3 H]LTB 4 competition studies indicated that 20-hydroxy-LTB 4 was 8 times, 6 trans-LTB 4 was 640 times and 20-carboxy-LTB 4 was 1000 times less effective than LTB 4 . The peptide leukotrienes C 4 , D 4 and E 4 showed no effect on [ 3 H]LTB 4 binding. Recovery rates averaged 97% after ethanol extraction and evaporation of known amounts of LTB 4 . The intra-assay coefficients of variation for three samples were 2.4%, 7.2% and 8.4%, respectively. This assay was validated by measuring LTB 4 released from human granulocytes stimulated with calcium ionophore A23187. The LTB 4 level was maximal at 10 min and decreased rapidly after 15 min. This radioreceptor assay for leukotriene B 4 is highly sensitive and is comparable to the reported sensitivity by radioimmunoassay. The method is simpler and less expensive than other methods such as high pressure liquid chromatography and is suitable for routine measurement of leukotriene B 4

Validation of a quantitative cerebrospinal fluid alpha-synuclein assay in a European-wide interlaboratory study

DEFF Research Database (Denmark)

Kruse, N.; Persson, S.; Alcolea, D.

2015-01-01

(one lot) were provided centrally and data reported back to one laboratory for data analysis. Our study showed that although factors such as preanalytical sample handling and lot-to-lot variability were minimized by our study design, we identified high variation in absolute values of CSF aSyn even when...... the same samples and same lots of assays were applied. We further demonstrate that although absolute concentrations differ between laboratories the quantitative results are comparable. With further standardization this assay may become an attractive tool for comparing aSyn measurements in diverse settings...... assay (ELISA) for the quantification of aSyn in CSF, we carried out a round robin trial with 18 participating laboratories trained in CSF ELISA analyses within the BIOMARKAPD project in the EU Joint Program -Neurodegenerative Disease Research. CSF samples (homogeneous aliquots from pools) and ELISA kits...

Results with commercial radioassay kits compared with microbiological assay of folate in serum and whole-blood

International Nuclear Information System (INIS)

McGown, E.L.; Lewis, C.M.; Dong, M.H.; Sauberlich, H.E.

1978-01-01

Results with three commercial folate radioassay kits [Bio-Rad, New England Nuclear (NEN), and RIA Products] were compared with those by microbiological assay for more than 200 samples of human serum and whole blood. All but one kit (NEN) compared favorably with the microbiological assay for serum samples, although there were notable diagnostic discrepancies. Two kits (NEN and Bio-Rad) were tested on whole-blood samples; both yielded values significantly higher than those by microbiological assay. The frequency distributions of erythrocyte folate data differed strikingly between the two kits; the NEN method yielded a much narrower range of normal values than did either the Bio-Rad or the microbiological assay. Radioassay kits appear to be suitable diagnostic agents for serum folate, if the behavior of a particular kit is investigated thoroughly before its routine use. However, the diagnostic value of radioassays of erythrocyte folate needs to be validated

Identification and quantification of amino acids from psoriatic and normal epidermis by high performance liquid chromatography

International Nuclear Information System (INIS)

Mahesar, S.M.; Khuhawar, M.Y.

2010-01-01

In this study, a modified fluorescence technique high performance liquid chromatography (HPLC) was adapted to separate the amino acids from the hydrolyzed keratin samples. These samples obtained from the epidermal layer of the normal and psoriatic human subjects. The keratin extracts are quantified in gram percentage of the dried skin and the amino acids concentrations are measured in mu g/g, mean retention time (tR), slope value and the coefficient of determination (r2) of each eluted amino acid is calculated. The coefficients of variation for amino acid standards ranged from 0.12% to 0.28%, mean, standard deviation of peak area and coefficients of variation of peak area were calculated. From the normal hydrolysated keratin protein fraction, 12 amino acids were determined and identified as aspartic acid, glutamic acid, asparagines, serine, glutamine, glycine, histidine, citrulline, arganine, fi-alanine, tyrosine, and valine. These amino acids were also determined in psoriatic samples while standard deviations (SD), standard error mean (SEM) and coefficient variation (CV%) of normal and psoriatic samples were also calculated. The higher concentration of amino acids in normal samples against psoriatic samples determined as glutamic acid 92.76+- 16. 83/50. 87+-9.88, glutamine 198.05+-18.74/19.74+-3.74 while higher concentrations of amino acids determined in psoriatic samples against normal samples as asparagines 81. 06+-10+-10.62/29. 98+-3.641; arganine 164.42+-35. 11/46. 14+-46, tyrosine 214.38+-29. 61/59. 64+-8. 82, and valine 169.7+-19.35/128.06+-15.14.1 is concluded that the absolute concentration of amino acids in psoriatic skin indicated a number of variations as compared to normal skin samples. (author)

Normal lymphographic findings and diagnostic errors in the retroperitoneal space

International Nuclear Information System (INIS)

Klein, U.; Heinze, H.G.

1980-01-01

Diagnostic erros in the lymphograms of 194 normal patients are shown to be due to topographical variations of the lymph system, influx and distribution of contrast media in the lymph ducts and nodes, and degenerative changes caused by old age. (orig.) [de

Mode instability in one-dimensional anharmonic lattices: Variational equation approach

Science.gov (United States)

Yoshimura, K.

1999-03-01

The stability of normal mode oscillations has been studied in detail under the single-mode excitation condition for the Fermi-Pasta-Ulam-β lattice. Numerical experiments indicate that the mode stability depends strongly on k/N, where k is the wave number of the initially excited mode and N is the number of degrees of freedom in the system. It has been found that this feature does not change when N increases. We propose an average variational equation - approximate version of the variational equation - as a theoretical tool to facilitate a linear stability analysis. It is shown that this strong k/N dependence of the mode stability can be explained from the view point of the linear stability of the relevant orbits. We introduce a low-dimensional approximation of the average variational equation, which approximately describes the time evolution of variations in four normal mode amplitudes. The linear stability analysis based on this four-mode approximation demonstrates that the parametric instability mechanism plays a crucial role in the strong k/N dependence of the mode stability.

A New Modified Histogram Matching Normalization for Time Series Microarray Analysis

Directory of Open Access Journals (Sweden)

Laura Astola

2014-07-01

Full Text Available Microarray data is often utilized in inferring regulatory networks. Quantile normalization (QN is a popular method to reduce array-to-array variation. We show that in the context of time series measurements QN may not be the best choice for this task, especially not if the inference is based on continuous time ODE model. We propose an alternative normalization method that is better suited for network inference from time series data.

Design and analysis of Q-RT-PCR assays for haematological malignancies using mixed effects models

DEFF Research Database (Denmark)

Bøgsted, Martin; Mandrup, Charlotte; Petersen, Anders

2009-01-01

research use and needs qualit control for accuracy and precision. Especially the identification of experimental variations and statistical analysis has recently created discussions. The standard analytical technique is to use the Delta-Delta-Ct method. Although this method accounts for sample specific...... developed based on a linear mixed effects model for factorial designs. The model consists of an analysis of variance where the variation of each fixed effect of interest and identified experimental and biological nuisance variations are split. Hereby it accounts for varying efficiency, inhomogeneous......The recent WHO classification of haematological malignancies includes detection of genetic abnormalities with rognostic significance. Consequently, an increasing number of specific real-time quantitative reverse transcription polymerase chain reaction (Q-RT-PCR) based assays are in clinical...

Establishment and clinical application of immunoradiometric assay for human growth hormone in serum

International Nuclear Information System (INIS)

Ji Jinfeng; Wu Congyuan; Niu Zhanpo; Zhang Kui; Song Ailing; Deng Jieying; Shi Mifan

1992-01-01

An immunoradiometric assay (IRMA) for human growth hormone (hGH) in serum is developed based on two high specific monoclonal antibodies against hGh. It can specifically detect the levels of serum bioactive hGh and had no cross-reaction with human prolactin (hPRL) and hGh oligmeric forms. The sensitivity was 0.2 ng/ml and the recovery for different concentrations of hGh was 92.0% ∼ 103.2%. The coefficients of variation for intra and inter-assay were<9.1% and <14.2%, respectively. Integral analysis of the results of RIA and IRMA with the patients' clinical manifestations revealed that hGh IRMA is better than hGh RIA in reflecting the clinical states of different acromegalic patients

Reduction of bias in neutron multiplicity assay using a weighted point model

Energy Technology Data Exchange (ETDEWEB)

Geist, W. H. (William H.); Krick, M. S. (Merlyn S.); Mayo, D. R. (Douglas R.)

2004-01-01

Accurate assay of most common plutonium samples was the development goal for the nondestructive assay technique of neutron multiplicity counting. Over the past 20 years the technique has been proven for relatively pure oxides and small metal items. Unfortunately, the technique results in large biases when assaying large metal items. Limiting assumptions, such as unifoh multiplication, in the point model used to derive the multiplicity equations causes these biases for large dense items. A weighted point model has been developed to overcome some of the limitations in the standard point model. Weighting factors are detemiined from Monte Carlo calculations using the MCNPX code. Monte Carlo calculations give the dependence of the weighting factors on sample mass and geometry, and simulated assays using Monte Carlo give the theoretical accuracy of the weighted-point-model assay. Measured multiplicity data evaluated with both the standard and weighted point models are compared to reference values to give the experimental accuracy of the assay. Initial results show significant promise for the weighted point model in reducing or eliminating biases in the neutron multiplicity assay of metal items. The negative biases observed in the assay of plutonium metal samples are caused by variations in the neutron multiplication for neutrons originating in various locations in the sample. The bias depends on the mass and shape of the sample and depends on the amount and energy distribution of the ({alpha},n) neutrons in the sample. When the standard point model is used, this variable-multiplication bias overestimates the multiplication and alpha values of the sample, and underestimates the plutonium mass. The weighted point model potentially can provide assay accuracy of {approx}2% (1 {sigma}) for cylindrical plutonium metal samples < 4 kg with {alpha} < 1 without knowing the exact shape of the samples, provided that the ({alpha},n) source is uniformly distributed throughout the

Telomere length in normal and neoplastic canine tissues.

Science.gov (United States)

Cadile, Casey D; Kitchell, Barbara E; Newman, Rebecca G; Biller, Barbara J; Hetler, Elizabeth R

2007-12-01

To determine the mean telomere restriction fragment (TRF) length in normal and neoplastic canine tissues. 57 solid-tissue tumor specimens collected from client-owned dogs, 40 samples of normal tissue collected from 12 clinically normal dogs, and blood samples collected from 4 healthy blood donor dogs. Tumor specimens were collected from client-owned dogs during diagnostic or therapeutic procedures at the University of Illinois Veterinary Medical Teaching Hospital, whereas 40 normal tissue samples were collected from 12 control dogs. Telomere restriction fragment length was determined by use of an assay kit. A histologic diagnosis was provided for each tumor by personnel at the Veterinary Diagnostic Laboratory at the University of Illinois. Mean of the mean TRF length for 44 normal samples was 19.0 kilobases (kb; range, 15.4 to 21.4 kb), and the mean of the mean TRF length for 57 malignant tumors was 19.0 kb (range, 12.9 to 23.5 kb). Although the mean of the mean TRF length for tumors and normal tissues was identical, tumor samples had more variability in TRF length. Telomerase, which represents the main mechanism by which cancer cells achieve immortality, is an attractive therapeutic target. The ability to measure telomere length is crucial to monitoring the efficacy of telomerase inhibition. In contrast to many other mammalian species, the length of canine telomeres and the rate of telomeric DNA loss are similar to those reported in humans, making dogs a compelling choice for use in the study of human anti-telomerase strategies.

Analytical evaluation of the automated galectin-3 assay on the Abbott ARCHITECT immunoassay instruments.

Science.gov (United States)

Gaze, David C; Prante, Christian; Dreier, Jens; Knabbe, Cornelius; Collet, Corinne; Launay, Jean-Marie; Franekova, Janka; Jabor, Antonin; Lennartz, Lieselotte; Shih, Jessie; del Rey, Jose Manuel; Zaninotto, Martina; Plebani, Mario; Collinson, Paul O

2014-06-01

Galectin-3 is secreted from macrophages and binds and activates fibroblasts forming collagen. Tissue fibrosis is central to the progression of chronic heart failure (CHF). We performed a European multicentered evaluation of the analytical performance of the two-step routine and Short Turn-Around-Time (STAT) galectin-3 immunoassay on the ARCHITECT i1000SR, i2000SR, and i4000SR (Abbott Laboratories). We evaluated the assay precision and dilution linearity for both routine and STAT assays and compared serum and plasma, and fresh vs. frozen samples. The reference interval and biological variability were also assessed. Measurable samples were compared between ARCHITECT instruments and between the routine and STAT assays and also to a galectin-3 ELISA (BG Medicine). The total assay coefficient of variation (CV%) was 2.3%-6.2% and 1.7%-7.4% for the routine and STAT assays, respectively. Both assays demonstrated linearity up to 120 ng/mL. Galectin-3 concentrations were higher in plasma samples than in serum samples and correlated well between fresh and frozen samples (R=0.997), between the routine and STAT assays, between the ARCHITECT i1000 and i2000 instruments and with the galectin-3 ELISA. The reference interval on 627 apparently healthy individuals (53% male) yielded upper 95th and 97.5th percentiles of 25.2 and 28.4 ng/mL, respectively. Values were significantly lower in subjects younger than 50 years. The galectin-3 routine and STAT assays on the Abbott ARCHITECT instruments demonstrated good analytical performance. Further clinical studies are required to demonstrate the diagnostic and prognostic potential of this novel marker in patients with CHF.

Characterization of multiple platelet activation pathways in patients with bleeding as a high-throughput screening option: use of 96-well Optimul assay.

Science.gov (United States)

Lordkipanidzé, Marie; Lowe, Gillian C; Kirkby, Nicholas S; Chan, Melissa V; Lundberg, Martina H; Morgan, Neil V; Bem, Danai; Nisar, Shaista P; Leo, Vincenzo C; Jones, Matthew L; Mundell, Stuart J; Daly, Martina E; Mumford, Andrew D; Warner, Timothy D; Watson, Steve P

2014-02-20

Up to 1% of the population have mild bleeding disorders, but these remain poorly characterized, particularly with regard to the roles of platelets. We have compared the usefulness of Optimul, a 96-well plate-based assay of 7 distinct pathways of platelet activation to characterize inherited platelet defects in comparison with light transmission aggregometry (LTA). Using Optimul and LTA, concentration-response curves were generated for arachidonic acid, ADP, collagen, epinephrine, Thrombin receptor activating-peptide, U46619, and ristocetin in samples from (1) healthy volunteers (n = 50), (2) healthy volunteers treated with antiplatelet agents in vitro (n = 10), and (3) patients with bleeding of unknown origin (n = 65). The assays gave concordant results in 82% of cases (κ = 0.62, P < .0001). Normal platelet function results were particularly predictive (sensitivity, 94%; negative predictive value, 91%), whereas a positive result was not always substantiated by LTA (specificity, 67%; positive predictive value, 77%). The Optimul assay was significantly more sensitive at characterizing defects in the thromboxane pathway, which presented with normal responses with LTA. The Optimul assay is sensitive to mild platelet defects, could be used as a rapid screening assay in patients presenting with bleeding symptoms, and detects changes in platelet function more readily than LTA. This trial was registered at www.isrctn.org as #ISRCTN 77951167.

Radio-immunoassay of antidiuretic hormone. Choice of a technic of extraction. Normal and pathological values

International Nuclear Information System (INIS)

Basuyau, J.P.; Brunelle, P.; Le Bihan, G.; Bourreille, J.; Bohuon, C.

1980-01-01

The low serum concentration of ADH requires extraction prior to assay. Various methods are compared (direct extraction by acetone, adsorption on talcum powder, Florisil, silicilic acid, Fuller's earth. QUSO, carbon-dextran, adsormone, then elution with hydrochloric acetone). The technic finally used was extraction with Florisil. The antibody used was commercially accessible. The separation of bound from free hormone required a second antibody fixed on Sephadex (DASP). The usual values found in 31 normal subjects from 22 to 89 years were: 7.4 . 4.1 pmol/l(M 2 tau) 1 pmol/l = 1.08 pg/ml. These assays were carried out on tissue extracts prepared by mashing tumour fragments or lymph nodes removed from a patient with the Schwartz Bartter syndrome. They showed the existence in these tissues of high concentrations of ADH immunologically identical with that present in the serum of normal subjects [fr

Single-Cell Based Quantitative Assay of Chromosome Transmission Fidelity.

Science.gov (United States)

Zhu, Jin; Heinecke, Dominic; Mulla, Wahid A; Bradford, William D; Rubinstein, Boris; Box, Andrew; Haug, Jeffrey S; Li, Rong

2015-03-30

Errors in mitosis are a primary cause of chromosome instability (CIN), generating aneuploid progeny cells. Whereas a variety of factors can influence CIN, under most conditions mitotic errors are rare events that have been difficult to measure accurately. Here we report a green fluorescent protein-based quantitative chromosome transmission fidelity (qCTF) assay in budding yeast that allows sensitive and quantitative detection of CIN and can be easily adapted to high-throughput analysis. Using the qCTF assay, we performed genome-wide quantitative profiling of genes that affect CIN in a dosage-dependent manner and identified genes that elevate CIN when either increased (icCIN) or decreased in copy number (dcCIN). Unexpectedly, qCTF screening also revealed genes whose change in copy number quantitatively suppress CIN, suggesting that the basal error rate of the wild-type genome is not minimized, but rather, may have evolved toward an optimal level that balances both stability and low-level karyotype variation for evolutionary adaptation. Copyright © 2015 Zhu et al.

A simple clot based assay for detection of procoagulant cell-derived microparticles.

Science.gov (United States)

Patil, Rucha; Ghosh, Kanjaksha; Shetty, Shrimati

2016-05-01

Cell-derived microparticles (MPs) are important biomarkers in many facets of medicine. However, the MP detection methods used till date are costly and time consuming. The main aim of this study was to standardize an in-house clot based screening method for MP detection which would not only be specific and sensitive, but also inexpensive. Four different methods of MP assessment were performed and the results correlated. Using the flow cytometry technique as the gold standard, 25 samples with normal phosphatidylserine (PS) expressing MP levels and 25 samples with elevated levels were selected, which was cross checked by the commercial STA Procoag PPL clotting time (CT) assay. A simple recalcification time and an in-house clot assay were the remaining two tests. The in-house test measures the CT after the addition of calcium chloride to MP rich plasma, following incubation with Russell viper venom and phospholipid free plasma. The CT obtained by the in-house assay significantly correlated with the results obtained by flow cytometry (R2=0.87, p<0.01). Though preliminary, the in-house assay seems to be efficient, inexpensive and promising. It could definitely be utilized routinely for procoagulant MP assessment in various clinical settings.

Intra-laboratory validation of a human cell based in vitro angiogenesis assay for testing angiogenesis modulators

Directory of Open Access Journals (Sweden)

Jertta-Riina Sarkanen

2011-01-01

Full Text Available The developed standardized human cell based in vitro angiogenesis assay was intra-laboratory validated to verify that the method is reliable and relevant for routine testing of modulators of angiogenesis e.g. pharmaceuticals and industrial chemicals. This assay is based on the earlier published method but it was improved and shown to be more sensitive and rapid than the previous assay. The performance of the assay was assessed by using 6 reference chemicals, which are widely used pharmaceuticals that inhibit angiogenesis: acetyl salicylic acid, erlotinib, 2-methoxyestradiol, levamisole, thalidomide, and anti-vascular endothelial growth factor. In the intra-laboratory validation, the sensitivity of the assay (upper and lower limits of detection and linearity of response in tubule formation, batch to batch variation in tubule formation between different Master cell bank batches, and precision as well as the reliability of the assay (reproducibility and repeatability were tested. The pre-set acceptance criteria for the intra-laboratory validation study were met. The relevance of the assay in man was investigated by comparing the effects of reference chemicals and their concentrations to the published human data. The comparison showed a good concordance, which indicates that this human cell based angiogenesis model predicts well the effects in man and has the potential to be used to supplement and/or replace of animal tests.

Normal stress databases in myocardial perfusion scintigraphy – how many subjects do you need?

DEFF Research Database (Denmark)

Trägårdh, Elin; Sjöstrand, Karl; Edenbrandt, Lars

2012-01-01

) for male, NC for female, attenuation‐corrected images (AC) for male and AC for female subjects. 126 male and 205 female subjects were included. The normal database was created by alternatingly computing the mean of all normal subjects and normalizing the subjects with respect to this mean, until...... convergence. Coefficients of variation (CV) were created for increasing number of included patients in the four different normal stress databases. Normal stress databases with ...Commercial normal stress databases in myocardial perfusion scintigraphy (MPS) commonly consist of 30–40 individuals. The aim of the study was to determine how many subjects are needed. Four normal stress databases were developed using patients who underwent 99mTc MPS: non‐corrected images (NC...

A Bayesian, generalized frailty model for comet assays.

Science.gov (United States)

Ghebretinsae, Aklilu Habteab; Faes, Christel; Molenberghs, Geert; De Boeck, Marlies; Geys, Helena

2013-05-01

This paper proposes a flexible modeling approach for so-called comet assay data regularly encountered in preclinical research. While such data consist of non-Gaussian outcomes in a multilevel hierarchical structure, traditional analyses typically completely or partly ignore this hierarchical nature by summarizing measurements within a cluster. Non-Gaussian outcomes are often modeled using exponential family models. This is true not only for binary and count data, but also for, example, time-to-event outcomes. Two important reasons for extending this family are for (1) the possible occurrence of overdispersion, meaning that the variability in the data may not be adequately described by the models, which often exhibit a prescribed mean-variance link, and (2) the accommodation of a hierarchical structure in the data, owing to clustering in the data. The first issue is dealt with through so-called overdispersion models. Clustering is often accommodated through the inclusion of random subject-specific effects. Though not always, one conventionally assumes such random effects to be normally distributed. In the case of time-to-event data, one encounters, for example, the gamma frailty model (Duchateau and Janssen, 2007 ). While both of these issues may occur simultaneously, models combining both are uncommon. Molenberghs et al. ( 2010 ) proposed a broad class of generalized linear models accommodating overdispersion and clustering through two separate sets of random effects. Here, we use this method to model data from a comet assay with a three-level hierarchical structure. Although a conjugate gamma random effect is used for the overdispersion random effect, both gamma and normal random effects are considered for the hierarchical random effect. Apart from model formulation, we place emphasis on Bayesian estimation. Our proposed method has an upper hand over the traditional analysis in that it (1) uses the appropriate distribution stipulated in the literature; (2) deals

Usual normalization strategies for gene expression studies impair the detection and analysis of circadian patterns.

Science.gov (United States)

Figueredo, Diego de Siqueira; Barbosa, Mayara Rodrigues; Coimbra, Daniel Gomes; Dos Santos, José Luiz Araújo; Costa, Ellyda Fernanda Lopes; Koike, Bruna Del Vechio; Alexandre Moreira, Magna Suzana; de Andrade, Tiago Gomes

2018-03-01

Recent studies have shown that transcriptomes from different tissues present circadian oscillations. Therefore, the endogenous variation of total RNA should be considered as a potential bias in circadian studies of gene expression. However, normalization strategies generally include the equalization of total RNA concentration between samples prior to cDNA synthesis. Moreover, endogenous housekeeping genes (HKGs) frequently used for data normalization may exhibit circadian variation and distort experimental results if not detected or considered. In this study, we controlled experimental conditions from the amount of initial brain tissue samples through extraction steps, cDNA synthesis, and quantitative real time PCR (qPCR) to demonstrate a circadian oscillation of total RNA concentration. We also identified that the normalization of the RNA's yield affected the rhythmic profiles of different genes, including Per1-2 and Bmal1. Five widely used HKGs (Actb, Eif2a, Gapdh, Hprt1, and B2m) also presented rhythmic variations not detected by geNorm algorithm. In addition, the analysis of exogenous microRNAs (Cel-miR-54 and Cel-miR-39) spiked during RNA extraction suggests that the yield was affected by total RNA concentration, which may impact circadian studies of small RNAs. The results indicate that the approach of tissue normalization without total RNA equalization prior to cDNA synthesis can avoid bias from endogenous broad variations in transcript levels. Also, the circadian analysis of 2 -Cycle threshold (Ct) data, without HKGs, may be an alternative for chronobiological studies under controlled experimental conditions.

Techniques for improving shuffler assay results for 55-gallon waste drums

International Nuclear Information System (INIS)

Rinard, P.M.; Prettyman, T.H.; Stuenkel, D.

1994-01-01

Accurate assays of the fissile contents in waste drums are needed to ensure the most proper and economical handling and disposal of the waste. An improvement of accuracy will mean fewer drums disposed as transuranic waste when they really contain low-level waste, saving both money and burial sites. Shufflers are used for assaying waste drums and are very accurate with nonmoderating matrices (such as iron). In the active mode they count delayed neutrons released after fissions are induced by irradiation neutrons from a 252 Cf source. However, as the hydrogen density from matrices such as paper or gloves increases, the accuracy can suffer without proper attention. The neutron transport and fission probabilities change with the hydrogen density, causing the neutron count rate to vary with the position of the fissile material within the drum. The magnitude of this variation grows with the hydrogen density

DNA-repair measurements by use of the modified comet assay

DEFF Research Database (Denmark)

Godschalk, Roger W L; Ersson, Clara; Riso, Patrizia

2013-01-01

The measurement of DNA-repair activity by extracts from cells or tissues by means of the single-cell gel electrophoresis (comet) assay has a high potential to become widely used in biomonitoring studies. We assessed the inter-laboratory variation in reported values of DNA-repair activity...... on substrate cells that had been incubated with Ro19-8022 plus light to generate oxidatively damaged DNA. Eight laboratories assessed the DNA-repair activity of three cell lines (i.e. one epithelial and two fibroblast cell lines), starting with cell pellets or with cell extracts provided by the coordinating...... laboratory. There was a large inter-laboratory variation, as evidenced by the range in the mean level of repair incisions between the laboratory with the lowest (0.002incisions/10(6)bp) and highest (0.988incisions/10(6)bp) incision activity. Nevertheless, six out of eight laboratories reported the same cell...

Nocturnal variations in subcutaneous blood flow rate in lower leg of normal human subjects

DEFF Research Database (Denmark)

Sindrup, J H; Kastrup, J; Jørgensen, B

1991-01-01

in central and local postural sympathetic vasoconstrictor activity. During sleep, characteristic variations in subcutaneous blood flow were disclosed. The 133Xe washout curve could be divided into three segments with significantly different slopes. Approximately 90 min after the subject went to sleep...

Assay strategies and methods for phospholipases

International Nuclear Information System (INIS)

Reynolds, L.J.; Washburn, W.N.; Deems, R.A.; Dennis, E.A.

1991-01-01

Of the general considerations discussed, the two issues which are most important in choosing an assay are (1) what sensitivity is required to assay a particular enzyme and (2) whether the assay must be continuous. One can narrow the options further by considering substrate availability, enzyme specificity, assay convenience, or the presence of incompatible side reactions. In addition, the specific preference of a particular phospholipase for polar head group, micellar versus vesicular substrates, and anionic versus nonionic detergents may further restrict the options. Of the many assays described in this chapter, several have limited applicability or serious drawbacks and are not commonly employed. The most commonly used phospholipase assays are the radioactive TLC assay and the pH-stat assay. The TLC assay is probably the most accurate, sensitive assay available. These aspects often outweigh the disadvantages of being discontinuous, tedious, and expensive. The radioactive E. coli assay has become popular recently as an alternative to the TLC assay for the purification of the mammalian nonpancreatic phospholipases. The assay is less time consuming and less expensive than the TLC assay, but it is not appropriate when careful kinetics are required. Where less sensitivity is needed, or when a continuous assay is necessary, the pH-stat assay is often employed. With purified enzymes, when free thiol groups are not present, a spectrophotometric thiol assay can be used. This assay is ∼ as sensitive as the pH-stat assay but is more convenient and more reproducible, although the substrate is not available commercially. Despite the many assay choices available, the search continues for a convenient, generally applicable assay that is both sensitive and continuous

A radioimmunoassay for erythropoietin: serum levels in normal human subjects and patients with hemopoietic disorders

International Nuclear Information System (INIS)

Rege, A.B.; Brookins, J.; Fisher, J.W.

1982-01-01

An RIA for Ep has been developed that is highly sensitive and specific. A homogeneous Ep preparation was labeled with 125 I by the chloramine-T method to a specific activity of 90 to 136 micro Ci/microgram and immunoreactivity of 80%. Ep antiserum, which was produced to a human urinary Ep preparation (80 U/mg of protein), was adsorbed with normal human urinary and serum proteins without any loss in sensitivity of the RIA to increase the specificity of the assay. A good correlation was seen between the RIA and the exhypoxic polycythemic mouse assay (corr. coef. 0.967; slope 1.05 and y intercept 0.75). Ep titers in sera from 175 hematologically normal human subjects exhibited a normal frequency distribution and ranged between 5.8 and 36.6 mU/ml with a mean of 14.9 +/- 4.7 (S.D.) and median of 14.3 Serum Ep titers were markedly elevated in seven patients with aplastic anemia and one patient with pure red cell aplasia (1350 to 20,640 mU/ml) and were lower than normal in two patients with polycythemia vera (8.1 and 9.4 mU/ml). The serum Ep titers in a prenephrectomy patient with chronic glomerulonephritis (32.1 mU/ml) decreased to below normal levels (9.04 mU/ml) after nephrectomy. The cord serum erythropoietin titers in 10 IDM [90.82 +/- 134.1 (S.D.) mu/ml] returned to values within the normal range (13.86 +/- 5.55) on day 3 after birth, suggesting the utility of the RIA in elucidating the role of hypoxia and/or insulin in increased erythropoiesis in IDM. The serum Ep titers in patients with anemias and polycythemias were compared to those of normal human subjects and agreed well with pathophysiologic mechanisms of these hemopoietic disorders, confirming the validity of the RIA

A radioimmunoassay for erythropoietin: serum levels in normal human subjects and patients with hemopoietic disorders

International Nuclear Information System (INIS)

Rege, A.B.; Brookins, J.; Fisher, J.W.

1982-01-01

An RIA for Ep has been developed that is highly sensitive and specific. A homogeneous Ep preparation was labeled with 125 I by the chloramine-T method to a specific activity of 90 to 136 μCi/μg and immunoreactivity of 80%. Ep antiserum, which was produced to a human urinary Ep preparation (80 U/mg of protein), was adsorbed with normal human urinary and serum proteins without any loss in sensitivity of the RIA to increase the specificity of the assay. A good correlation was seen between the RIA and the exhypoxic polycythemic mouse assay (corr. coef. 0.967; slope 1.05 and ''y'' intercept 0.75). Ep titers in sera from 175 hematologically normal human subjects exhibited a normal frequency distribution and ranged between 5.8 and 36.6 mU/ml with a mean of 14.9 +/- 4.7 (S.D.) and median of 14.3. Serum Ep titers were markedly elevated in seven patients with aplastic anemia and one patient with pure red cell aplasia (1350 to 20,640 mU/ml) and were lower than normal in two patients with polycythemia vera (8.1 and 9.4 mU/ml). The serum Ep titers in a prenephrectomy patient with chronic glomerulonephritis (31.1 mU/ml) decreased to below normal levels (9.04 mU/ml) after nephrectomy. The cord serum erythropoietin titers in 10 IDM [90.82 +/- 134.1 (S.D.) mu/ml] returned to values within the normal range (13.86 +/- 5.55) on day 3 after birth, suggesting the utility of the RIA in elucidating the role of hypoxia and/or insulin in increased erythropoiesis in IDM. The serum Ep titers in patients with anemias and polycythemias were compared to those of normal human subjects and agreed well with pathophysiologic mechanisms of these hemopoietic disorders, confirming the validity of the RIA

Improved performance of a double antibody radioimmunoassay for carcinoembryonic antigen

International Nuclear Information System (INIS)

Zimmerman, R.

1979-01-01

A new double antibody solid-phase radioimmunoassay (RIA) for carcinoembryonic antigen (CEA) is critically analyzed. The aim of the study was 4-fold: (a) to define the level of sensitivity (a comparison of 3 different assay procedures revealed that the author's sequential assay was more sensitive than most previously reported RIAs, while competitive and non-equilibrium assay had wider measuring ranges); (b) to analyze recoveries of CEA in either serum, plasma or urine (the recovery , even in urine, was very close to expected values, indicating that no CEA is lost or degraded during brief storage or in the extraction procedure); (c) to evaluate inter- and intra-assay variations, since most clinical management is dependent on serial assays rather than single determinations. The coefficients of variation were low both within and between assays. A change of 3 ng CEA is required for significant change (>2 S.D.) at the normal serum level which is 16 ng CEA/ml in the authors assay. At levels above normal, a change of 4 ng is required; (d) the assay was also developed for determination of CEA levels in a large series of perchlorid acid treated serum, plasma or urine samples. This forms the basis for an assay suitable for serial assays with high sensitivity and accuracy in various neoplastic diseases. (Auth.)

Superfluid to normal phase transition and extreme regularity od superdeformed bands

CERN Document Server

Pavlichenkov, I M

2002-01-01

The exact semiclassical expression for the second inertial parameter B for the superfluid and normal phases is derived. Interpolation between these limiting values shows that the function B(I) changes sign at the spin I sub c , which is critical for a rotational spectrum. The quantity B turns out to be a sensitive measure of the change in static pairing correlations. The superfluid-to-normal transition reveals itself in the specific variation of the ratio B/A versus spin I with the plateau characteristic of the normal phase. This dependence is find to be universal for normal deformed and superdeformed nuclei. The long plateau with a small value B/A approx A sup - sup 8 sup / sup 3 explains the extreme regularity of superdeformed bands

Management strategy in pregnancies with elevated second-trimester maternal serum alpha-fetoprotein based on a second assay.

Science.gov (United States)

Spaggiari, Emmanuel; Ruas, Marie; Dreux, Sophie; Valat, Anne-Sylvie; Czerkiewicz, Isabelle; Guimiot, Fabien; Schmitz, Thomas; Delezoide, Anne-Lise; Muller, Françoise

2013-04-01

To assess maternal-fetal outcomes in pregnancies associated with persistently elevated second-trimester maternal serum alpha-fetoprotein. A retrospective cohort study in 658 patients with maternal serum alpha-fetoprotein ≥2.5 multiple of median, performed at routine Down syndrome screening. Maternal serum alpha-fetoprotein was assayed a second time in 341 of them. Outcomes were recorded in all cases. The group with unexplained maternal serum alpha-fetoprotein persistently ≥2.5 multiple of median was associated with more pregnancy complications 37 of 92 (40.2%) as fetal death, preeclampsia, intrauterine growth restriction, and congenital nephrotic syndrome, compared with the group with maternal serum alpha-fetoprotein that returned to a normal level 37 of 226 (16.4%) (P alpha-fetoprotein returns to a normal level on a second assay, the risk of adverse outcome significantly decreases, but these pregnancies are still at risk of complications and therefore need close surveillance. Repeat maternal serum alpha-fetoprotein assay allows identification of patients who should be offered amniocentesis to evaluate the risk of nephrotic syndrome and epidermolysis bullosa. Alpha-fetoprotein should be monitored in pregnancies associated with unexplained high maternal serum alpha-fetoprotein. A management strategy based on ultrasound examination, second maternal serum alpha-fetoprotein assay and amniocentesis is proposed to improve prenatal counseling and management of such pregnancies. However, a prospective study remains necessary to evaluate it. Copyright © 2013 Mosby, Inc. All rights reserved.

A lack of cerebral lateralization in schizophrenia is within the normal variation in brain maturation but indicates late, slow maturation.

Science.gov (United States)

Saugstad, L F

1999-10-19

The planum temporale (PT) bias, PT leftward, PT symmetry, and PT rightward reversal and sidedness preference, consistent right-handedness, ambilaterality, and consistent left-handedness are placed on a continuum mirroring the normal variation in rate of brain maturation. Maturational rate declines as we pass from PT leftward bias and consistent right-handedness to PT reversal and consistent left-handedness. Concomitantly, we expect an increased prevalence of males due to their pubertal age being about 2 years later than that of females, and a shift in cognitive profile from higher verbal scores than performance scores on the WAIS to higher performance than verbal scores. Three disorders fulfilling the criteria of late CNS maturation apart from the corresponding cognitive profile were studied: infantile autism (IA), schizophrenia (S), and developmental dyslexia (DD). These disorders have in common deficits in cognition, perception, and somatomotor function. The deficits range from an arrest in brain development (which is evident in infancy superimposed on late maturation in IA) to overall delayed brain and somatic development in S (culminating in postpubertal psychotic episodes and persistent and generalized residual deficits). Finally, reading inability, problems in perception (vision and hearing) and in motor coordination, particularly between the two hemispheres, characterize DD. Enhancing brain maturation and the prevalence of 'normal' cerebral asymmetry--laterality is preferable if we want to reduce the risk of developing the above-mentioned disorders. It is suggested that in the past environmental challenges have favored early maturation, with its abundant neuronal population, arborization and excessive density of synapses and cerebral excitability which has powered evolution through the mechanism of natural selection. Early maturation is obtainable through optimal nutrition, including a satisfactory amount of marine fat (PUFA), before and during pregnancy and

Development of simple immunoradiometric assays using avidin coupled to polystyrene beads as a common solid phase

International Nuclear Information System (INIS)

Jyotsna, N.; Singh, Y.; Chouthkanthiwar, V.; Paradkar, S.; Sivaprasad, N.

1998-01-01

In this paper, we describe the preparation and application of avidin coupled polystyrene beads as a common solid phase for use in immunoradiometric assays (IRMAs). The assay system is based on two matched commercial monoclonal antibodies, of which, the capture antibody is biotinylated using biotinamidocaproate N-hydroxysuccinimide ester and the detection antibody is radiolabeled with 125 I by conventional Chloramine-T method. Avidin was immobilized on the polystyrene beads through a primary coat of bovine serum albumin using glutaraldhyde activation method. Various factors, such as concentration of reagents, incubation time, etc. were optimised to obtain a simple assay protocol consisting of only two pipetting steps, namely, that of a mixture of the two labelled antibodies (radiolabelled and biotinylated) and of the standard or sample. The advantage of the Avidin-Biotin system is the improved sensitivity, economy of antibody and the possibility to use a common solid phase in assays for different analytes. Using the polystyrene beads along with the novel decanting device, it has been possible to achieve the convenience of the 'coated-tube' technology without the expensive automation necessary for large scale preparation of antibody coated tubes. This protocol has been successfully applied to Prolactin, LH and FSH assays. The sensitivity of the Prolactin assay is 8μIU/mL (0.3 ng/mL), that of the FSH assay is 1mIU/mL and that of the LH assay is 0.9 mIU/mL. The intra-assay and inter-assay variations were <10%. Shelf life of the avidin coupled beads was found to be about 8 months and that of the biotin labelled antibodies up to 18 months. (author)

Magnetization transfer imaging of normal and abnormal testis: preliminary results

International Nuclear Information System (INIS)

Tsili, Athina C.; Ntorkou, Alexandra; Maliakas, Vasilios; Argyropoulou, Maria I.; Baltogiannis, Dimitrios; Sylakos, Anastasios; Sofikitis, Nikolaos; Stavrou, Sotirios; Astrakas, Loukas G.

2016-01-01

The aim was to determine the magnetization transfer ratio (MTR) of normal testes, possible variations with age and to assess the feasibility of MTR in characterizing various testicular lesions. Eighty-six men were included. A three-dimensional gradient-echo MT sequence was performed, with/without an on-resonance binomial prepulse. MTR was calculated as: (SIo-SIm)/(SIo) x 100 %, where SIm and SIo refers to signal intensities with and without the saturation pulse, respectively. Subjects were classified as: group 1, 20-39 years; group 2, 40-65 years; and group 3, older than 65 years of age. Analysis of variance (ANOVA) followed by the least significant difference test was used to assess variations of MTR with age. Comparison between the MTR of normal testis, malignant and benign testicular lesions was performed using independent-samples t testing. ANOVA revealed differences of MTR between age groups (F = 7.51, P = 0.001). Significant differences between groups 1, 2 (P = 0.011) and 1, 3 (P < 0.001) were found, but not between 2, 3 (P = 0.082). The MTR (in percent) of testicular carcinomas was 55.0 ± 3.2, significantly higher than that of benign lesions (50.3 ± 4.0, P = 0.02) and of normal testes (47.4 ± 2.2, P < 0.001). MTR of normal testes decreases with age. MTR might be helpful in the diagnostic work-up of testicular lesions. (orig.)

Subclinical Hypothyroidism in Children: Normal Variation or Sign of a Failing Thyroid Gland?

Directory of Open Access Journals (Sweden)

Kaplowitz PaulB

2010-05-01

Full Text Available Subclinical hypothyroidism (SCH, defined by a normal total or free T4 level and a mildly elevated TSH (typically 5–10 mU/L, is common in children, but there is currently no consensus on management. Several recent pediatric studies indicate that progression of SCH to overt hypothyroidism (OH is uncommon and that over a period of several years, elevated TSH usually either normalizes or persists but does not increase. The etiology appears to be multifactorial, with some cases representing minor developmental abnormalities, some related to obesity, some to mild autoimmune thyroiditis, and some associated with mutations in the gene for the TSH-receptor. There are no pediatric studies showing clinical benefit of treating these children with thyroid hormone, but additional studies in this area are needed. Since few cases of pediatric SCH progress to OH, treatment can be deferred, and periodic follow-up testing may be the preferred strategy, with elevated thyroid antibodies or a goiter being considered risk factors for eventual OH.

Vertebral artery variations and osseous anomaly at the C1-2 level diagnosed by 3D CT angiography in normal subjects

Energy Technology Data Exchange (ETDEWEB)

Wakao, Norimitsu; Kamiya, Mitsuhiro [Aichi Medical University, Department of Spine Center, Aichi (Japan); Aichi Medical University, Department of Orthopedic Surgery, Nagakute, Aichi (Japan); Takeuchi, Mikinobu; Hirasawa, Atsuhiko; Kawanami, Katsuhisa; Takayasu, Masakazu [Aichi Medical University, Department of Spine Center, Aichi (Japan); Nishimura, Manabu [Aichi Medical University, Department of Radiology, Nagakute, Aichi (Japan); Riew, K.D. [Washington University, Department of Orthopedic Surgery, St. Louis, MO (United States); Imagama, Shiro [Nagoya University, Department of Orthopedic Surgery, Nagoya, Aichi (Japan); Sato, Keiji [Aichi Medical University, Department of Orthopedic Surgery, Nagakute, Aichi (Japan)

2014-10-15

The craniovertebral junction is anatomically complicated. Representative vertebral artery (VA) variations include the persistent first intersegmental artery (FIA), fenestration of the VA above and below C1 (FEN), posterior inferior cerebellar artery (PICA) from C1/2, and high-riding VA (HRVA). The ponticulus posticus (PP) is a well-known osseous anomaly at C1. Although those anomalies are frequent in patients with cervical deformity, the prevalence of these in subjects with normal cervical spines is still unknown. The aim of this study is to investigate the variations and prevalence of vascular and osseous anomalies based on three-dimensional computed tomographic (3D CT) angiography in patients without any cervical diseases, such as rheumatoid arthritis, Klippel-Feil syndrome, or Down syndrome. Eligible subjects were patients who underwent 3D CT angiography by the Department of Otorhinolaryngology and Internal Medicine from January 2009 to October 2013 in our institution. The authors defined a HRVA as a C2 pedicle with a maximum diameter of 4 mm or less. Among 480 subjects with a mean age of 63.1 years, 387 patients were eligible. One hundred and eighteen subjects were female, and 269 were male. HRVA was observed in 10.1 % of patients (39 out of 387 cases), FIA in 1.8 % (7 cases), FEN in 1.3 % (5 cases), and PICA in 1.3 % (5 cases). PP was observed in 6.2 % of patients (24 cases). According to past reports, many VA anomalies could be attributed to congenital or acquired conditions (e.g., rheumatoid arthritis). However, VA anomalies appear to exist even in patients without any such cervical diseases. (orig.)

Protein Analytical Assays for Diagnosing, Monitoring, and Choosing Treatment for Cancer Patients

Directory of Open Access Journals (Sweden)

Alicia D. Powers

2012-01-01

Full Text Available Cancer treatment is often hindered by inadequate methods for diagnosing the disease or insufficient predictive capacity regarding therapeutic efficacy. Targeted cancer treatments, including Bcr-Abl and EGFR kinase inhibitors, have increased survival for some cancer patients but are ineffective in other patients. In addition, many patients who initially respond to targeted inhibitor therapy develop resistance during the course of treatment. Molecular analysis of cancer cells has emerged as a means to tailor treatment to particular patients. While DNA analysis can provide important diagnostic information, protein analysis is particularly valuable because proteins are more direct mediators of normal and diseased cellular processes. In this review article, we discuss current and emerging protein assays for improving cancer treatment, including trends toward assay miniaturization and measurement of protein activity.

Solid phase assays

International Nuclear Information System (INIS)

Reese, M.G.; Johnson, L.R.; Ransom, D.K.

1980-01-01

In a solid phase assay for quantitative determination of biological and other analytes, a sample such as serum is contacted with a receptor for the analyte being assayed, the receptor being supported on a solid support. No tracer for the analyte is added to the sample before contacting with the receptor; instead the tracer is contacted with the receptor after unbound analyte has been removed from the receptor. The assay can be otherwise performed in a conventional manner but can give greater sensitivity. (author)

A serum and platelet-rich plasma serotonin assay using liquid chromatography tandem mass spectrometry for monitoring of neuroendocrine tumor patients.

Science.gov (United States)

Korse, Catharina M; Buning-Kager, Johanna C G M; Linders, Theodora C; Heijboer, Annemieke C; van den Broek, Daan; Tesselaar, Margot E T; van Tellingen, Olaf; van Rossum, Huub H

2017-06-01

Serotonin is used for the diagnosis and follow-up of neuroendocrine tumors (NET). We describe the analytical and clinical validation of a liquid chromatography tandem mass spectrometry (LC-MS/MS) based serotonin assay for serum and platelet-rich plasma (PRP). An LC-MS/MS based method for serum and PRP serotonin was validated by determination of assay imprecision, carry-over, linearity, interference, recovery, sample stability and a matrix/method comparison of serum and PRP serotonin was made with whole blood serotonin. Furthermore, upper limits of normal were determined and serotonin concentrations of healthy individuals, 14 NET patients without evidence of disease and 51 NET patients with evidence of disease were compared. For serum and PRP fractions, total assay imprecision was serotonin upper limit of normal were 5.5nmol/10 9 platelet and 5.1nmol/10 9 platelet, respectively. NET patients with confirmed evidence of disease had significantly higher serum and PRP serotonin levels when compared to NET patients without evidence of disease and healthy volunteers. LC-MS/MS based serum and PRP serotonin assays were developed with suitable analytical characteristics. Furthermore, serum and PRP serotonin was found to be useful for monitoring NET patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Detection of induced male germline mutation: Correlations and comparisons between traditional germline mutation assays, transgenic rodent assays and expanded simple tandem repeat instability assays

Energy Technology Data Exchange (ETDEWEB)

Singer, Timothy M. [Mutagenesis Section, Environmental and Occupational Toxicology Division, Safe Environments Programme, 0803A, Health Canada, Ottawa, Ont., K1A 0K9 (Canada); Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ont., K1S 5B6 (Canada); Lambert, Iain B. [Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ont., K1S 5B6 (Canada); Williams, Andrew [Biostatistics and Epidemiology Division, Safe Environments Programme, 6604B, Health Canada, Ottawa, Ont., K1A 0K9 (Canada); Douglas, George R. [Mutagenesis Section, Environmental and Occupational Toxicology Division, Safe Environments Programme, 0803A, Health Canada, Ottawa, Ont., K1A 0K9 (Canada); Yauk, Carole L. [Mutagenesis Section, Environmental and Occupational Toxicology Division, Safe Environments Programme, 0803A, Health Canada, Ottawa, Ont., K1A 0K9 (Canada)]. E-mail: carole_yauk@hc-sc.gc.ca

2006-06-25

Several rodent assays are capable of monitoring germline mutation. These include traditional assays, such as the dominant lethal (DL) assay, the morphological specific locus (SL) test and the heritable translocation (HT) assay, and two assays that have been developed more recently-the expanded simple tandem repeat (ESTR) and transgenic rodent (TGR) mutation assays. In this paper, we have compiled the limited amount of experimental data that are currently available to make conclusions regarding the comparative ability of the more recently developed assays to detect germline mutations induced by chemical and radiological agents. The data suggest that ESTR and TGR assays are generally comparable with SL in detecting germline mutagenicity induced by alkylating agents and radiation, though TGR offered less sensitivity than ESTR in some cases. The DL and HT assays detect clastogenic events and are most susceptible to mutations arising in post-spermatogonial cells, and they may not provide the best comparisons with TGR and ESTR instability. The measurement of induced ESTR instability represents a relatively sensitive method of identifying agents causing germline mutation in rodents, and may also be useful for bio-monitoring exposed individuals in the human population. Any future use of the TGR and ESTR germline mutation assays in a regulatory testing context will entail more robust and extensive characterization of assay performance. This will require substantially more data, including experiments measuring multiple endpoints, a greatly expanded database of chemical agents and a focus on characterizing stage-specific activity of mutagens in these assays, preferably by sampling epididymal sperm exposed at defined pre-meiotic, meiotic and post-meiotic stages of development.

Detection of induced male germline mutation: Correlations and comparisons between traditional germline mutation assays, transgenic rodent assays and expanded simple tandem repeat instability assays

International Nuclear Information System (INIS)

Singer, Timothy M.; Lambert, Iain B.; Williams, Andrew; Douglas, George R.; Yauk, Carole L.

2006-01-01

Several rodent assays are capable of monitoring germline mutation. These include traditional assays, such as the dominant lethal (DL) assay, the morphological specific locus (SL) test and the heritable translocation (HT) assay, and two assays that have been developed more recently-the expanded simple tandem repeat (ESTR) and transgenic rodent (TGR) mutation assays. In this paper, we have compiled the limited amount of experimental data that are currently available to make conclusions regarding the comparative ability of the more recently developed assays to detect germline mutations induced by chemical and radiological agents. The data suggest that ESTR and TGR assays are generally comparable with SL in detecting germline mutagenicity induced by alkylating agents and radiation, though TGR offered less sensitivity than ESTR in some cases. The DL and HT assays detect clastogenic events and are most susceptible to mutations arising in post-spermatogonial cells, and they may not provide the best comparisons with TGR and ESTR instability. The measurement of induced ESTR instability represents a relatively sensitive method of identifying agents causing germline mutation in rodents, and may also be useful for bio-monitoring exposed individuals in the human population. Any future use of the TGR and ESTR germline mutation assays in a regulatory testing context will entail more robust and extensive characterization of assay performance. This will require substantially more data, including experiments measuring multiple endpoints, a greatly expanded database of chemical agents and a focus on characterizing stage-specific activity of mutagens in these assays, preferably by sampling epididymal sperm exposed at defined pre-meiotic, meiotic and post-meiotic stages of development

Describing temporal variation in reticuloruminal pH using continuous monitoring data

DEFF Research Database (Denmark)

Denwood, M. J.; Kleen, J. L.; Jensen, D. B.

2018-01-01

Reticuloruminal pH has been linked to subclinical disease in dairy cattle, leading to considerable interest in identifying pH observations below a given threshold. The relatively recent availability of continuously monitored data from pH boluses gives new opportunities for characterizing the normal...... patterns of pH over time and distinguishing these from abnormal patterns using more sensitive and specific methods than simple thresholds. We fitted a series of statistical models to continuously monitored data from 93 animals on 13 farms to characterize normal variation within and between animals. We used...... a subset of the data to relate deviations from the normal pattern to the productivity of 24 dairy cows from a single herd. Our findings show substantial variation in pH characteristics between animals, although animals within the same farm tended to show more consistent patterns. There was strong evidence...

The variation field of the radiosensitivity in the human population: hypersensitivity and hypo sensitivity

International Nuclear Information System (INIS)

Bouffler, S.

2009-01-01

It is generally admitted in the radiotherapy practice that 5% of patients will present serious reactions of normal tissues. Studies made on human population confirm it exists variations of cell radiosensitivity and genetic factors contribute in a significant manner to the observed variations. The researches of markers able to predict the reactions of normal tissues to the therapy focussed on the identification of sensitive sub-group. It is however obvious that exists also a part of the population relatively hypo sensitive. It would be interesting to make studies on the genome to find genes associated to serious reactions of normal tissues to radiotherapy. (N.C.)

Challenges in clinical natural language processing for automated disorder normalization.

Science.gov (United States)

Leaman, Robert; Khare, Ritu; Lu, Zhiyong

2015-10-01

Identifying key variables such as disorders within the clinical narratives in electronic health records has wide-ranging applications within clinical practice and biomedical research. Previous research has demonstrated reduced performance of disorder named entity recognition (NER) and normalization (or grounding) in clinical narratives than in biomedical publications. In this work, we aim to identify the cause for this performance difference and introduce general solutions. We use closure properties to compare the richness of the vocabulary in clinical narrative text to biomedical publications. We approach both disorder NER and normalization using machine learning methodologies. Our NER methodology is based on linear-chain conditional random fields with a rich feature approach, and we introduce several improvements to enhance the lexical knowledge of the NER system. Our normalization method - never previously applied to clinical data - uses pairwise learning to rank to automatically learn term variation directly from the training data. We find that while the size of the overall vocabulary is similar between clinical narrative and biomedical publications, clinical narrative uses a richer terminology to describe disorders than publications. We apply our system, DNorm-C, to locate disorder mentions and in the clinical narratives from the recent ShARe/CLEF eHealth Task. For NER (strict span-only), our system achieves precision=0.797, recall=0.713, f-score=0.753. For the normalization task (strict span+concept) it achieves precision=0.712, recall=0.637, f-score=0.672. The improvements described in this article increase the NER f-score by 0.039 and the normalization f-score by 0.036. We also describe a high recall version of the NER, which increases the normalization recall to as high as 0.744, albeit with reduced precision. We perform an error analysis, demonstrating that NER errors outnumber normalization errors by more than 4-to-1. Abbreviations and acronyms are found

Normalization method for metabolomics data using optimal selection of multiple internal standards

Directory of Open Access Journals (Sweden)

Yetukuri Laxman

2007-03-01

Full Text Available Abstract Background Success of metabolomics as the phenotyping platform largely depends on its ability to detect various sources of biological variability. Removal of platform-specific sources of variability such as systematic error is therefore one of the foremost priorities in data preprocessing. However, chemical diversity of molecular species included in typical metabolic profiling experiments leads to different responses to variations in experimental conditions, making normalization a very demanding task. Results With the aim to remove unwanted systematic variation, we present an approach that utilizes variability information from multiple internal standard compounds to find optimal normalization factor for each individual molecular species detected by metabolomics approach (NOMIS. We demonstrate the method on mouse liver lipidomic profiles using Ultra Performance Liquid Chromatography coupled to high resolution mass spectrometry, and compare its performance to two commonly utilized normalization methods: normalization by l2 norm and by retention time region specific standard compound profiles. The NOMIS method proved superior in its ability to reduce the effect of systematic error across the full spectrum of metabolite peaks. We also demonstrate that the method can be used to select best combinations of standard compounds for normalization. Conclusion Depending on experiment design and biological matrix, the NOMIS method is applicable either as a one-step normalization method or as a two-step method where the normalization parameters, influenced by variabilities of internal standard compounds and their correlation to metabolites, are first calculated from a study conducted in repeatability conditions. The method can also be used in analytical development of metabolomics methods by helping to select best combinations of standard compounds for a particular biological matrix and analytical platform.

Sensitivity of Raman spectroscopy to normal patient variability

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Vargis, Elizabeth; Byrd, Teresa; Logan, Quinisha; Khabele, Dineo; Mahadevan-Jansen, Anita

2011-11-01

Many groups have used Raman spectroscopy for diagnosing cervical dysplasia; however, there have been few studies looking at the effect of normal physiological variations on Raman spectra. We assess four patient variables that may affect normal Raman spectra: Race/ethnicity, body mass index (BMI), parity, and socioeconomic status. Raman spectra were acquired from a diverse population of 75 patients undergoing routine screening for cervical dysplasia. Classification of Raman spectra from patients with a normal cervix is performed using sparse multinomial logistic regression (SMLR) to determine if any of these variables has a significant effect. Results suggest that BMI and parity have the greatest impact, whereas race/ethnicity and socioeconomic status have a limited effect. Incorporating BMI and obstetric history into classification algorithms may increase sensitivity and specificity rates of disease classification using Raman spectroscopy. Studies are underway to assess the effect of these variables on disease.

Effect of nifedipine on gastric emptying in normal subjects

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Traube, M.; Lange, R.C.; McAllister, R.G.; McCallum, R.W.

1985-05-01

Nifedipine (N) inhibits calcium entry into smooth muscle cells and relaxes esophageal smooth muscle. The authors studied N's effect on gastric emptying of liquids and solids. Ten normal subjects underwent radionuclide (In-111-DTPA in water and Tc-99m-sulfur colloid tagged to chicken liver) emptying tests with and without 30 mg N given orally 20 min prior to meal ingestion. Peak plasma N levels were either 30 or 60 min after drug dosing and showed a 3-fold variation (low 145 ng/ml, high 434 ng/ml). Both mean N levels and integral concentration time values were twice as high as those obtained after 30 mg sublingual dosing in normals previously studied in our lab. The authors conclude that plasma N levels which are associated with significant esophageal motility effects do not change gastric emptying in normal subjects. The data also show that N levels are greater after oral than sublingual dosing of 30 mg in normal subjects.

Effect of nifedipine on gastric emptying in normal subjects

International Nuclear Information System (INIS)

Traube, M.; Lange, R.C.; McAllister, R.G.; McCallum, R.W.

1985-01-01

Nifedipine (N) inhibits calcium entry into smooth muscle cells and relaxes esophageal smooth muscle. The authors studied N's effect on gastric emptying of liquids and solids. Ten normal subjects underwent radionuclide (In-111-DTPA in water and Tc-99m-sulfur colloid tagged to chicken liver) emptying tests with and without 30 mg N given orally 20 min prior to meal ingestion. Peak plasma N levels were either 30 or 60 min after drug dosing and showed a 3-fold variation (low 145 ng/ml, high 434 ng/ml). Both mean N levels and integral concentration time values were twice as high as those obtained after 30 mg sublingual dosing in normals previously studied in our lab. The authors conclude that plasma N levels which are associated with significant esophageal motility effects do not change gastric emptying in normal subjects. The data also show that N levels are greater after oral than sublingual dosing of 30 mg in normal subjects

Anatomical variations in dorsal metatarsal arteries with surgical significance: A cadaveric study

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Preeti Shivshankar Awari

2017-01-01

Full Text Available Introduction: Based on angiosome concept to revascularize a particular artery, the microvascular and reconstructive surgeons must know the anatomy and variations in the arteries in that specific region of the body to achieve better results. Nowadays, dorsal metatarsal artery (DMTA perforator flaps and toe grafts are becoming popular which also demand adequate information about normal anatomy and variants in these arteries for fruitful results. Materials and Methods: The authors studied normal anatomy and variations in the origin of DMTAs in 50 lower extremities of 25 embalmed cadavers. Results: The authors found many variations as the absence of DMTAs, origin of the DMTA from the deep plantar arch. The places wherever the arcuate artery was absent the lateral tarsal artery gave rise to dorsal metatarsal arteries. Conclusion: Being familiar with the incidence of anatomical variations in the origin of the DMTAs can increase vigilance in vascular and reconstructive surgeries leading to better prognosis. surgeries leading to better prognosis.

Normal variation and long-term reproducibility of image-selected in vivo brain MR spectroscopy

International Nuclear Information System (INIS)

Smith, M.A.; Porter, D.; Lowry, M.; Ayton, V.; Twelves, C.J.; Richards, M.A.; Garlick, P.; Maisey, M.N.

1988-01-01

MR spectroscopy of P-31 in the brain was performed with a 1.5-T MR imaging and spectroscopy system using ISIS with a 5-cm cube. A standardized spectral processing routine was adopted, and the ratios of peak areas were measured. Localized brain spectra were obtained from 17 healthy subjects, of whom ten had undergone repeated investigations after a delay of at least 1 month. The variation among healthy subjects, expressed as the mean +- standard deviation, and the long-term reproducibility, expressed as the coefficient of variation, were as follows: for peak areas phosphocreatine (PCr) Pi 2.46 +- 0.72, 21.3%, for PCr/PME, 1.97 +- 0.62, 16.8%, for PCr/PDE, 0.51 +- 0.07, 8.1%; for PCr/Υ-adenosine triphosphate (ATP), 1.13 + 0.15, 6.3%; for PCr/α-ATP, 1.09 +- 0.21, 10.3%, for PCr/β-ATP, 1.66 +- .027, 10.4%; and for pH, 7.00 +- 0.05, 0.8%

Preparation of anti-Sudan red monoclonal antibody and development of an indirect competitive enzyme-linked immunosorbent assay for detection of Sudan red in chilli jam and chilli oil.

Science.gov (United States)

Xu, Jing; Zhang, Yuanyang; Yi, Jian; Meng, Meng; Wan, Yuping; Feng, Caiwei; Wang, Shanliang; Lu, Xiao; Xi, Rimo

2010-10-01

Sudan dyes are banned to be used in food additives because of the carcinogenicity of their metabolites. A rapid and sensitive indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed to detect the residues of Sudan dyes. Novel immunogen and coating antigen were synthesized via glutaraldehyde linking. The hapten-bovine serum albumin (BSA) was applied as immunogen and the hapten-ovalbumin (OVA) was served as coating antigen. The monoclonal antibody obtained showed high sensitivity to Sudan I with an IC(50) value of 1.7 μg L(-1) in buffer and was suitable to detect the residues of Sudan red in food products. The specificity of the assay was studied by measuring cross-reactivity of the antibody with the structurally related compounds of Sudan II (red (120%). Chilli jam and chilli oil samples spiked with Sudan dyes were analyzed by the method. The detection limit (LOD) of the ELISA method applied in chilli jam and chilli oil was 9.0 μg L(-1) and 19.6 μg L(-1), respectively. The recovery rates of Sudan-I in chilli oil and chilli jam were in the range of 80%-110% with coefficients of variation <25%. The intra-assay variation and inter-assay variation in buffer were both <9%.

A versatile electrowetting-based digital microfluidic platform for quantitative homogeneous and heterogeneous bio-assays

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Vergauwe, Nicolas; Witters, Daan; Ceyssens, Frederik; Vermeir, Steven; Verbruggen, Bert; Puers, Robert; Lammertyn, Jeroen

2011-05-01

Electrowetting-on-dielectric (EWOD) lab-on-a-chip systems have already proven their potential within a broad range of bio-assays. Nevertheless, research on the analytical performance of those systems is limited, yet crucial for a further breakthrough in the diagnostic field. Therefore, this paper presents the intrinsic possibilities of an EWOD lab-on-a-chip as a versatile platform for homogeneous and heterogeneous bio-assays with high analytical performance. Both droplet dispensing and splitting cause variations in droplet size, thereby directly influencing the assay's performance. The extent to which they influence the performance is assessed by a theoretical sensitivity analysis, which allows the definition of a basic framework for the reduction of droplet size variability. Taking advantage of the optimized droplet manipulations, both homogeneous and heterogeneous bio-assays are implemented in the EWOD lab-on-a-chip to demonstrate the analytical capabilities and versatility of the device. A fully on-chip enzymatic assay is realized with high analytical performance. It demonstrates the promising capabilities of an EWOD lab-on-a-chip in food-related and medical applications, such as nutritional and blood analyses. Further, a magnetic bio-assay for IgE detection using superparamagnetic nanoparticles is presented whereby the nanoparticles are used as solid carriers during the bio-assay. Crucial elements are the precise manipulation of the superparamagnetic nanoparticles with respect to dispensing and separation. Although the principle of using nano-carriers is demonstrated for protein detection, it can be easily extended to a broader range of bio-related applications like DNA sensing. In heterogeneous bio-assays the chip surface is actively involved during the execution of the bio-assay. Through immobilization of specific biological compounds like DNA, proteins and cells a reactive chip surface is realized, which enhances the bio-assay performance. To demonstrate

A Highly Sensitive Telomerase Activity Assay that Eliminates False-Negative Results Caused by PCR Inhibitors

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Hidenobu Yaku

2013-09-01

Full Text Available An assay for telomerase activity based on asymmetric polymerase chain reaction (A-PCR on magnetic beads (MBs and subsequent application of cycling probe technology (CPT is described. In this assay, the telomerase reaction products are immobilized on MBs, which are then washed to remove PCR inhibitors that are commonly found in clinical samples. The guanine-rich sequences (5'-(TTAGGGn-3' of the telomerase reaction products are then preferentially amplified by A-PCR, and the amplified products are subsequently detected via CPT, where a probe RNA with a fluorophore at the 5' end and a quencher at the 3' end is hydrolyzed by RNase H in the presence of the target DNA. The catalyst-mediated cleavage of the probe RNA enhances fluorescence from the 5' end of the probe. The assay allowed us to successfully detect HeLa cells selectively over normal human dermal fibroblast (NHDF cells. Importantly, this selectivity produced identical results with regard to detection of HeLa cells in the absence and presence of excess NHDF cells; therefore, this assay can be used for practical clinical applications. The lower limit of detection for HeLa cells was 50 cells, which is lower than that achieved with a conventional telomeric repeat amplification protocol assay. Our assay also eliminated false-negative results caused by PCR inhibitors. Furthermore, we show that this assay is appropriate for screening among G-quadruplex ligands to find those that inhibit telomerase activity.

Adaptive nonlinear control using input normalized neural networks

International Nuclear Information System (INIS)

Leeghim, Henzeh; Seo, In Ho; Bang, Hyo Choong

2008-01-01

An adaptive feedback linearization technique combined with the neural network is addressed to control uncertain nonlinear systems. The neural network-based adaptive control theory has been widely studied. However, the stability analysis of the closed-loop system with the neural network is rather complicated and difficult to understand, and sometimes unnecessary assumptions are involved. As a result, unnecessary assumptions for stability analysis are avoided by using the neural network with input normalization technique. The ultimate boundedness of the tracking error is simply proved by the Lyapunov stability theory. A new simple update law as an adaptive nonlinear control is derived by the simplification of the input normalized neural network assuming the variation of the uncertain term is sufficiently small

The diagnostic value of ventilation-perfusion scintigraphy combined with plasma D-dimer assay in diagnosis of pulmonary embolism

International Nuclear Information System (INIS)

Wang Qian; Huang Lili; Qin Shuling; Yue Minggang; Wang Yu; Nie Yuxin; Liang Tiejun

2005-01-01

Objective: To investigate the clinical diagnostic value of ventilation-perfusion scintigraphy combined with plasma D-dimer assay in diagnosis of pulmonary embolism (PE). Methods: One hundred and four patients with clinically suspected PE underwent both pulmonary ventilation-perfusion scintigraphy and plasma D-dimer assay. According to the criteria of prospective investigation of the pulmonary embolism diagnosis (PIOPED), ventilation-perfusion scintigraphy was interpreted as normal, very low or low probability of PE, intermediate probability of PE and high probability of PE. High probability was considered as positive; normal and very low or low probability as negative and intermediate probability as non-diagnostic. Plasma D-dimer levels were measured using a quantitative immunoturbidimetric method, and a cut-off value of 500 mg/L was used in the diagnosis of PE. Clinical diagnostic value of ventilation-perfusion scintigraphy, D-dimer assay and combined use of ventilation-perfusion scintigraphy and D-dimer assay for diagnosing PE was evaluated, respectively, comparing with the final clinical diagnosis that was based on the clinical findings. Results: Among the 104 patients, 44 were diagnosed with PE and 60 were excluded. Ventilation-perfusion scintigraphy provided diagnostic interpretations for 86 (82.7%) patients, and non-diagnostic interpretations for 18 (17.3%) patients. For diagnosing PE, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of ventilation-perfusion scintigraphy was 84.1%, 75.0%, 78.8%, 71.2% and 86.5%, respectively, and with D-dimer assay was 93.2%, 60.0%, 74.0%, 63.1% and 92.3%, respectively. If a plasma D-dimer level of < 500 mg/L was taken as a criterion to exclude PE for those intermediate probability of ventilation-perfusion scintigraphy, the diagnostic specificity and accuracy would be raised to 85.0% and 84.6%, respectively. Conclusions: When a non-diagnostic interpretation was occurred on

Geographic variation in shortleaf pine (Pinus echinata Mill.) - cortical monoterpenes

Science.gov (United States)

R.C. Schmidtling; J.H. Myszewski; C.E. McDaniel

2005-01-01

Cortical monoterpenes were assayed in bud tissue from 16 Southwide Southern Pine Seed Source Study (SSPSS) sources and from 6 seed orchard sources fiom across the natural range of the species, to examine geogaphic variation in shortleaf pine. Spruce pine and pond pine were also sampled. The results show geographic differences in all of the major terpenes. There was no...

Radiation-induced normal tissue damage: implications for radiotherapy

International Nuclear Information System (INIS)

Prasanna, Pataje G.

2014-01-01

Radiotherapy is an important treatment modality for many malignancies, either alone or as a part of combined modality treatment. However, despite technological advances in physical treatment delivery, patients suffer adverse effects from radiation therapy due to normal tissue damage. These side effects may be acute, occurring during or within weeks after therapy, or intermediate to late, occurring months to years after therapy. Minimizing normal tissue damage from radiotherapy will allow enhancement of tumor killing and improve tumor control and patients quality of life. Understanding mechanisms through which radiation toxicity develops in normal tissue will facilitate the development of next generation radiation effect modulators. Translation of these agents to the clinic will also require an understanding of the impact of these protectors and mitigators on tumor radiation response. In addition, normal tissues vary in radiobiologically important ways, including organ sensitivity to radiation, cellular turnover rate, and differences in mechanisms of injury manifestation and damage response. Therefore, successful development of radiation modulators may require multiple approaches to address organ/site-specific needs. These may include treatments that modify cellular damage and death processes, inflammation, alteration of normal flora, wound healing, tissue regeneration and others, specifically to counter cancer site-specific adverse effects. Further, an understanding of mechanisms of normal tissue damage will allow development of predictive biomarkers; however harmonization of such assays is critical. This is a necessary step towards patient-specific treatment customization. Examples of important adverse effects of radiotherapy either alone or in conjunction with chemotherapy, and important limitations in the current approaches of using radioprotectors for improving therapeutic outcome will be highlighted. (author)

Hormone assay

International Nuclear Information System (INIS)

Eisentraut, A.M.

1977-01-01

An improved radioimmunoassay is described for measuring total triiodothyronine or total thyroxine levels in a sample of serum containing free endogenous thyroid hormone and endogenous thyroid hormone bound to thyroid hormone binding protein. The thyroid hormone is released from the protein by adding hydrochloric acid to the serum. The pH of the separated thyroid hormone and thyroid hormone binding protein is raised in the absence of a blocking agent without interference from the endogenous protein. 125 I-labelled thyroid hormone and thyroid hormone antibodies are added to the mixture, allowing the labelled and unlabelled thyroid hormone and the thyroid hormone antibody to bind competitively. This results in free thyroid hormone being separated from antibody bound thyroid hormone and thus the unknown quantity of thyroid hormone may be determined. A thyroid hormone test assay kit is described for this radioimmunoassay. It provides a 'single tube' assay which does not require blocking agents for endogenous protein interference nor an external solid phase sorption step for the separation of bound and free hormone after the competitive binding step; it also requires a minimum number of manipulative steps. Examples of the assay are given to illustrate the reproducibility, linearity and specificity of the assay. (UK)

A tissue biopsy-based epigenetic multiplex PCR assay for prostate cancer detection

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Van Neste Leander

2012-06-01

Full Text Available Abstract Background PSA-directed prostate cancer screening leads to a high rate of false positive identifications and an unnecessary biopsy burden. Epigenetic biomarkers have proven useful, exhibiting frequent and abundant inactivation of tumor suppressor genes through such mechanisms. An epigenetic, multiplex PCR test for prostate cancer diagnosis could provide physicians with better tools to help their patients. Biomarkers like GSTP1, APC and RASSF1 have demonstrated involvement with prostate cancer, with the latter two genes playing prominent roles in the field effect. The epigenetic states of these genes can be used to assess the likelihood of cancer presence or absence. Results An initial test cohort of 30 prostate cancer-positive samples and 12 cancer-negative samples was used as basis for the development and optimization of an epigenetic multiplex assay based on the GSTP1, APC and RASSF1 genes, using methylation specific PCR (MSP. The effect of prostate needle core biopsy sample volume and age of formalin-fixed paraffin-embedded (FFPE samples was evaluated on an independent follow-up cohort of 51 cancer-positive patients. Multiplexing affects copy number calculations in a consistent way per assay. Methylation ratios are therefore altered compared to the respective singleplex assays, but the correlation with patient outcome remains equivalent. In addition, tissue-biopsy samples as small as 20 μm can be used to detect methylation in a reliable manner. The age of FFPE-samples does have a negative impact on DNA quality and quantity. Conclusions The developed multiplex assay appears functionally similar to individual singleplex assays, with the benefit of lower tissue requirements, lower cost and decreased signal variation. This assay can be applied to small biopsy specimens, down to 20 microns, widening clinical applicability. Increasing the sample volume can compensate the loss of DNA quality and quantity in older samples.

Neutron monitor generated data distributions in quantum variational Monte Carlo

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Kussainov, A. S.; Pya, N.

2016-08-01

We have assessed the potential applications of the neutron monitor hardware as random number generator for normal and uniform distributions. The data tables from the acquisition channels with no extreme changes in the signal level were chosen as the retrospective model. The stochastic component was extracted by fitting the raw data with splines and then subtracting the fit. Scaling the extracted data to zero mean and variance of one is sufficient to obtain a stable standard normal random variate. Distributions under consideration pass all available normality tests. Inverse transform sampling is suggested to use as a source of the uniform random numbers. Variational Monte Carlo method for quantum harmonic oscillator was used to test the quality of our random numbers. If the data delivery rate is of importance and the conventional one minute resolution neutron count is insufficient, we could always settle for an efficient seed generator to feed into the faster algorithmic random number generator or create a buffer.

Mutagenicity of irradiated food in the host mediated assay system

International Nuclear Information System (INIS)

Johnston-Arthur, T.; Turanitz, K.; Hruby, R.; Stehlik, G.; Brena-Valle, M.

1975-01-01

Groups of Swiss albino mice (SPF) fed with normal and gamma-irradiated food at doses of 0.75, 1.5 and 3.0 Mrad, were injected intraperitoneally with SALMONELLA TYPHIMURIUM TA 1530 for the host mediated assay test of mutagenesis. The mutation frequency was calculated in terms of the number of mutant colonies per unit number of surviving cells. The results indicate that there is a significant increase in mutation frequency induced by the 3 Mrad sterilized food. No difference was observed in the 0.75 Mrad dose when compared with the control

Causal Genetic Variation Underlying Metabolome Differences.

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Swain-Lenz, Devjanee; Nikolskiy, Igor; Cheng, Jiye; Sudarsanam, Priya; Nayler, Darcy; Staller, Max V; Cohen, Barak A

2017-08-01

An ongoing challenge in biology is to predict the phenotypes of individuals from their genotypes. Genetic variants that cause disease often change an individual's total metabolite profile, or metabolome. In light of our extensive knowledge of metabolic pathways, genetic variants that alter the metabolome may help predict novel phenotypes. To link genetic variants to changes in the metabolome, we studied natural variation in the yeast Saccharomyces cerevisiae We used an untargeted mass spectrometry method to identify dozens of metabolite Quantitative Trait Loci (mQTL), genomic regions containing genetic variation that control differences in metabolite levels between individuals. We mapped differences in urea cycle metabolites to genetic variation in specific genes known to regulate amino acid biosynthesis. Our functional assays reveal that genetic variation in two genes, AUA1 and ARG81 , cause the differences in the abundance of several urea cycle metabolites. Based on knowledge of the urea cycle, we predicted and then validated a new phenotype: sensitivity to a particular class of amino acid isomers. Our results are a proof-of-concept that untargeted mass spectrometry can reveal links between natural genetic variants and metabolome diversity. The interpretability of our results demonstrates the promise of using genetic variants underlying natural differences in the metabolome to predict novel phenotypes from genotype. Copyright © 2017 by the Genetics Society of America.

Influences of Normalization Method on Biomarker Discovery in Gas Chromatography-Mass Spectrometry-Based Untargeted Metabolomics: What Should Be Considered?

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Chen, Jiaqing; Zhang, Pei; Lv, Mengying; Guo, Huimin; Huang, Yin; Zhang, Zunjian; Xu, Fengguo

2017-05-16

Data reduction techniques in gas chromatography-mass spectrometry-based untargeted metabolomics has made the following workflow of data analysis more lucid. However, the normalization process still perplexes researchers, and its effects are always ignored. In order to reveal the influences of normalization method, five representative normalization methods (mass spectrometry total useful signal, median, probabilistic quotient normalization, remove unwanted variation-random, and systematic ratio normalization) were compared in three real data sets with different types. First, data reduction techniques were used to refine the original data. Then, quality control samples and relative log abundance plots were utilized to evaluate the unwanted variations and the efficiencies of normalization process. Furthermore, the potential biomarkers which were screened out by the Mann-Whitney U test, receiver operating characteristic curve analysis, random forest, and feature selection algorithm Boruta in different normalized data sets were compared. The results indicated the determination of the normalization method was difficult because the commonly accepted rules were easy to fulfill but different normalization methods had unforeseen influences on both the kind and number of potential biomarkers. Lastly, an integrated strategy for normalization method selection was recommended.

Phenolsulphotransferase in human tissue: radiochemical enzymatic assay and biochemical properties

International Nuclear Information System (INIS)

Anderson, R.J.; Weinshilboum, R.M.

1980-01-01

Phenolsulphotransferase (EC 2.8.2.1) (PST) is an important catecholamine and drug metabolizing enzyme. Optimal conditions have been determined for the accurate measurement of PST activity in the human platelet, human renal cortex, and human jejunum with a radiochemical microassay. 3-Methoxy-4-hydroxyphenylglycol (MHPG) and 35 S-3'-phosphoadenosine-5'-phosphosulfate ( 35 S-PAPS) were the substrates for the reaction. The apparent Michaelis-Menten (Ksub(m)) values for MHPG with platelet, renal cortex, and jejunum were 1.09, 0.46 and 1.16 mmol/l, respectively. Apparent Ksub(m) values for PAPS in the same tissues were 0.14, 0.13 and 0.21 μmol/l. The pH optimum of the reacton in all three tissues was approximately 6.2-6.8 with three different buffer systems. The coefficients of variation for the assay of platelet, renal cortex, and jejunal activities were 6.2%, 3.4% and 4.4%, respectively. Mean platelet PST activity in blood samples from 75 randomly selected adult subjects was 5.0 +- 1.72 mmol of MHPG sulfate formed per hour per mg of platelet protein (8.3 X 10 -5 +- 2.9 X 10 -5 μmol min -1 mg -1 , mean +- S.D.). There was a 5-fold intersubject variation in platelet PST activity within two standard deviations of the mean value. Experiments in which partially purified human erythrocyte PST was added to platelet, kidney and gut homogenates under these assay conditions provided evidence that endogenous PST inhibitors did not affect the observed enzyme activity. (Auth.)

Queen Size Variation in the Ponerine Ant Ponera coarctata (Hymenoptera: Formicidae

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J. Liebig

1995-01-01

Full Text Available Queens of Ponera coarctata show a pronounced variation in size as measured by ommatidia number and Weber's alitrunk length. Isometric size variation and the normal distribution of size categories indicate that, despite these differences, only one queen morph exists. Queen size varies less within colonies than between colonies, and thus appears to be colony specific. Ovary length apparently varies with queen size. Similar size variations as in queens also occured in males, but not in workers.

Contingent negative variation of mood disorder patients

Institute of Scientific and Technical Information of China (English)

Yingzhi Lu; Wenbin Zong; Qingtao Ren; Jinyu Pu; Jun Chen; Juan Li; Xingshi Chen; Yong Wang

2011-01-01

Studies on brain-evoked potential and contingent negative variation (CNV) in mood disorder remain controversial. To date, no CNV difference between unipolar and bipolar depression has been reported. Brain-evoked potentials were measured in the present study to analyze CNV in three subtypes of mood disorder (mania, unipolar depression, and bipolar depression), and these results were compared with normal controls. In the mania group, CNV amplitude B was greater than in controls, and the depression group exhibited lower CNV amplitude B and smaller A-S'2 area, and prolonged post-imperative negative variation latency. The CNV comparison between unipolar and bipolar depression found that the prolonged post-imperative negative variation latency was only in unipolar depression. These results suggest that prolonged post-imperative negative variation latency is a characteristic of unipolar depression, and CNV amplitude change is a state characteristic of mood disorder patients.

Development and validation of a real-time PCR assay for specific and sensitive detection of canid herpesvirus 1.

Science.gov (United States)

Decaro, Nicola; Amorisco, Francesca; Desario, Costantina; Lorusso, Eleonora; Camero, Michele; Bellacicco, Anna Lucia; Sciarretta, Rossana; Lucente, Maria Stella; Martella, Vito; Buonavoglia, Canio

2010-10-01

A TaqMan-based real-time PCR assay targeting the glycoprotein B-encoding gene was developed for diagnosis of canid herpesvirus 1 (CHV-1) infection. The established assay was highly specific, since no cross-reactions were observed with other canine DNA viruses, including canine parvovirus type 2, canine minute virus, or canine adenovirus types 1 and 2. The detection limit was 10(1) and 1.20 x 10(1) DNA copies per 10 microl(-1) of template for standard DNA and a CHV-1-positive kidney sample, respectively: about 1-log higher than a gel-based PCR assay targeting the thymidine kinase gene. The assay was also reproducible, as shown by satisfactory low intra-assay and inter-assay coefficients of variation. CHV-1 isolates of different geographical origins were recognised by the TaqMan assay. Tissues and clinical samples collected from three pups which died of CHV-1 neonatal infection were also tested, displaying a wide distribution of CHV-l DNA in their organs. Unlike other CHV-1-specific diagnostic methods, this quantitative assay permits simultaneous detection and quantitation of CHV-1 DNA in a wide range of canine tissues and body fluids, thus providing a useful tool for confirmation of a clinical diagnosis, for the study of viral pathogenesis and for evaluation of the efficacy of vaccines and antiviral drugs. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Evaluation of the Thermo Scientific SureTect Listeria species assay. AOAC Performance Tested Method 071304.

Science.gov (United States)

Cloke, Jonathan; Evans, Katharine; Crabtree, David; Hughes, Annette; Simpson, Helen; Holopainen, Jani; Wickstrand, Nina; Kauppinen, Mikko; Leon-Velarde, Carlos; Larson, Nathan; Dave, Keron

2014-01-01

The Thermo Scientific SureTect Listeria species Assay is a new real-time PCR assay for the detection of all species of Listeria in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested Methods program to validate the SureTect Listeria species Assay in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996 including amendment 1:2004 in a variety of foods plus plastic and stainless steel. The food matrixes validated were smoked salmon, processed cheese, fresh bagged spinach, cantaloupe, cooked prawns, cooked sliced turkey meat, cooked sliced ham, salami, pork frankfurters, and raw ground beef. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, three matrixes (pork frankfurters, fresh bagged spinach, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled independent laboratory study by the University ofGuelph, Canada. Using probability of detection statistical analysis, a significant difference in favour of the SureTect assay was demonstrated between the SureTect and reference method for high level spiked samples of pork frankfurters, smoked salmon, cooked prawns, stainless steel, and low-spiked samples of salami. For all other matrixes, no significant difference was seen between the two methods during the study. Inclusivity testing was conducted with 68 different isolates of Listeria species, all of which were detected by the SureTect Listeria species Assay. None of the 33 exclusivity isolates were detected by the SureTect Listeria species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation, which demonstrated that the assay gave reliable performance. Accelerated stability testing was additionally conducted, validating the assay

The Davies-Gray titration for the assay of uranium in nuclear materials: a performance study

International Nuclear Information System (INIS)

Bickel, M.

1997-01-01

An interlaboratory comparison in two phases was organized to assess the precision and accuracy concerning the assay of uranium in nuclear materials by the potentiometric titration method. This contribution presents the results of this exercise in terms of method performance. Variations to be expected between different laboratories and within a single laboratory are estimated. In general, the method proved again very reliable. (orig.)

Estimates of DNA damage by the comet assay in the direct-developing frog Eleutherodactylus johnstonei (Anura, Eleutherodactylidae

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Laura Carolina Valencia

2011-01-01

Full Text Available The aim of this study was to use the Comet assay to assess genetic damage in the direct-developing frog Eleutherodactylus johnstonei. A DNA diffusion assay was used to evaluate the effectiveness of alkaline, enzymatic and alkaline/enzymatic treatments for lysing E. johnstonei blood cells and to determine the amount of DNA strand breakage associated with apoptosis and necrosis. Cell sensitivity to the mutagens bleomycin (BLM and 4-nitroquinoline-1-oxide (4NQO was also assessed using the Comet assay, as was the assay reproducibility. Alkaline treatment did not lyse the cytoplasmic and nuclear membranes of E. johnstonei blood cells, whereas enzymatic digestion with proteinase K (40 !g/mL yielded naked nuclei. The contribution of apoptosis and necrosis (assessed by the DNA diffusion assay to DNA damage was estimated to range from 0% to 8%. BLM and 4NQO induced DNA damage in E. johnstonei blood cells at different concentrations and exposure times. Dose-effect curves with both mutagens were highly reproducible and showed consistently low coefficients of variation (CV < 10%. The results are discussed with regard to the potential use of the modified Comet assay for assessing the exposure of E. johnstonei to herbicides in ecotoxicological studies.

Estimates of DNA damage by the comet assay in the direct-developing frog Eleutherodactylus johnstonei (Anura, Eleutherodactylidae).

Science.gov (United States)

Valencia, Laura Carolina; García, Adriana; Ramírez-Pinilla, Martha Patricia; Fuentes, Jorge Luis

2011-10-01

The aim of this study was to use the Comet assay to assess genetic damage in the direct-developing frog Eleutherodactylus johnstonei. A DNA diffusion assay was used to evaluate the effectiveness of alkaline, enzymatic and alkaline/enzymatic treatments for lysing E. johnstonei blood cells and to determine the amount of DNA strand breakage associated with apoptosis and necrosis. Cell sensitivity to the mutagens bleomycin (BLM) and 4-nitro-quinoline-1-oxide (4NQO) was also assessed using the Comet assay, as was the assay reproducibility. Alkaline treatment did not lyse the cytoplasmic and nuclear membranes of E. johnstonei blood cells, whereas enzymatic digestion with proteinase K (40 μg/mL) yielded naked nuclei. The contribution of apoptosis and necrosis (assessed by the DNA diffusion assay) to DNA damage was estimated to range from 0% to 8%. BLM and 4NQO induced DNA damage in E. johnstonei blood cells at different concentrations and exposure times. Dose-effect curves with both mutagens were highly reproducible and showed consistently low coefficients of variation (CV ≤ 10%). The results are discussed with regard to the potential use of the modified Comet assay for assessing the exposure of E. johnstonei to herbicides in ecotoxicological studies.

Evaluation of assays for quantification of DNA in canine plasma as an indirect marker of NETosis.

Science.gov (United States)

Smith, Stephanie A; Lawson, Corinne M; McMichael, Maureen A; Jung, Katrina; O'Brien, Mauria; Achiel, Ron

2017-06-01

Neutrophil extracellular traps (NET), consisting of a filamentous DNA/chromatin-histone scaffold originating from neutrophils are part of the innate immune response, may be released under a variety of inflammatory conditions and are associated with an increased risk for thrombosis. The purpose of this study was to evaluate a SYTOX green fluorescence assay and a histone-DNA complex (hisDNA) ELISA for quantification of NET-related DNA in canine plasma. The influence of variations in blood sample handling on assay results was tested. Accuracy of the SYTOX green fluorescence and the hisDNA ELISA was evaluated with dilutional linearity using serial dilutions. Interference was assessed by addition of purified bilirubin or hemoglobin. Precision was determined by calculating the intra- and inter-assay CV. Preanalytic sample handling did not influence DNA measurements by either assay. Citrate and EDTA plasma samples were equivalent. For the DNA fluorescence assay, dilutional linearity was poor due to autofluorescence, which was corrected by addition of canine plasma to the diluent. The presence of bilirubin and hemoglobin also increased autofluorescence, and resulted in falsely low concentrations of DNA. On the hisDNA ELISA, pigmentemia had no effect. Both assays as modified in this study are suitable for measuring DNA in canine EDTA or citrate plasma. However, performance of the fluorescence assay was impacted by pigmentemia, and it was less sensitive than the ELISA in detecting the presence of nucleosome material in the plasma. © 2017 American Society for Veterinary Clinical Pathology.

A urine midmolecule osteocalcin assay shows higher discriminatory power than a serum midmolecule osteocalcin assay during short-term alendronate treatment of osteoporotic patients.

Science.gov (United States)

Srivastava, A K; Mohan, S; Singer, F R; Baylink, D J

2002-07-01

We isolated and characterized a peptide fragment corresponding to amino acid sequence 14-28 of human osteocalcin in urine from Paget's disease, and developed a polyclonal antibody reactive to this peptide in urine. We used this antibody to measure urinary fragments of osteocalcin and compared to efficacy of the urinary osteocalcin assay with a serum osteocalcin (sOC) assay (ELISA-Osteo, Cis-Bio International) to monitor the short-term changes in bone turnover in response to alendronate treatment. The synthetic peptide-based urinary osteocalcin (uOC) radioimmunoassay (RIA) showed an analytical sensitivity of 6.25 ng/mL, standard curve range of 3.12-400 ng/mL, and mean intra- (n = 20) and interassay (n = 30) coefficient of variation (CV) of sALP) (Alkphose-B, Metra Biosystems) in serum samples. The percent change data obtained between baseline and 30 days (n = 18) posttreatment suggested a rapid decline in uOC concentration (-27%, p sALP (-3.4%, p = 0.689), two specific markers of bone formation. As expected, due to the coupling of bone formation and bone resorption, the concentration of all markers showed a 30%-45% decline compared with baseline values after 90 days (n = 16) of treatment. Correlation of markers after a 30 day treatment with alendronate revealed a higher correlation (r = 0.61, p sALP (r = -0.14, p = 0.295) with uNTx. Similarly, correlation coefficients with r values between 0.48 and 0.55 (p < 0.05) were observed between uOC, sNTx, and sCTx, whereas no significant correlation was observed between sOC and sNTx or sCTx. These results provide indirect evidence that fragments measured by the urine assay probably originated from bone resorption, and suggest that the uOC assay could be used to assess short-term changes in bone metabolism with regard to osteocalcin.

Circadian variation of urinary albumin excretion in pregnancy

NARCIS (Netherlands)

Douma, C. E.; van der Post, J. A.; van Acker, B. A.; Boer, K.; Koopman, M. G.

1995-01-01

OBJECTIVE: The hypothesis was tested that circadian variations in urinary albumin excretion of pregnant women in the third trimester of normal pregnancy are different from nonpregnant individuals. DESIGN: Circadian variability in urinary albumin excretion was studied both in pregnant women and in

Estimation of biological variation and reference change value of glycated hemoglobin (HbA(1c)) when two analytical methods are used.

Science.gov (United States)

Ucar, Fatma; Erden, Gonul; Ginis, Zeynep; Ozturk, Gulfer; Sezer, Sevilay; Gurler, Mukaddes; Guneyk, Ahmet

2013-10-01

Available data on biological variation of HbA1c revealed marked heterogeneity. We therefore investigated and estimated the components of biological variation for HbA1c in a group of healthy individuals by applying a recommended and strictly designed study protocol using two different assay methods. Each month, samples were derived on the same day, for three months. Four EDTA whole blood samples were collected from each individual (20 women, 9 men; 20-45 years of age) and stored at -80°C until analysis. HbA1c values were measured by both high performance liquid chromatography (HPLC) (Shimadzu, Prominence, Japan) and boronate affinity chromatography methods (Trinity Biotech, Premier Hb9210, Ireland). All samples were assayed in duplicate in a single batch for each assay method. Estimations were calculated according to the formulas described by Fraser and Harris. The within subject (CV(I))-between subject (CV(G)) biological variations were 1.17% and 5.58%, respectively for HPLC. The calculated CV(I) and CV(G) were 2.15% and 4.03%, respectively for boronate affinity chromatography. Reference change value (RCV) for HPLC and boronate affinity chromatography was 5.4% and 10.4% respectively and individuality index of HbA(1c) was 0.35 and 0.93 respectively. This study for the first time described the components of biological variation for HbA1c in healthy individuals by two different assay methods. Obtained findings showed that the difference between CV(A) values of the methods might considerably affect RCV. These data regarding biological variation of HbA(1c) could be useful for a better evaluation of HbA(1c) test results in clinical interpretation. Copyright © 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Kidney volume in type 1 (insulin-dependent) diabetic patients with normal or increased urinary albumin excretion

DEFF Research Database (Denmark)

Feldt-Rasmussen, B; Hegedüs, L; Mathiesen, E R

1991-01-01

Forty-seven patients with type 1 (insulin-dependent) diabetes mellitus and 14 normal subjects had renal volume determined by an ultrasonic technique. Renal volume of 299 +/- 49 ml/1.73 m2 (mean +/- SD) in type 1 diabetic patients with normal urinary albumin excretion exceeded that in the normal...... subjects (245 +/- 53 ml/1.73 m2, p less than 0.05). Compared with diabetic patients with normal urinary albumin excretion, renal volume was significantly higher in patients with microalbuminuria (372 +/- 24 ml/1.73 m2, p less than 0.05) and patients with clinical nephropathy (352 +/- 48 ml/1.73 m2, p less...... than 0.05). In a multiple linear regression with HbA1c, urinary albumin excretion, age, diabetes duration and mean blood pressure as independent variables, variations in HbA1c could account for 33% of the variations in kidney volume (n = 47, r = 0.57, p less than 0.01). The other variables played...

Apparent Transition in the Human Height Distribution Caused by Age-Dependent Variation during Puberty Period

Science.gov (United States)

Iwata, Takaki; Yamazaki, Yoshihiro; Kuninaka, Hiroto

2013-08-01

In this study, we examine the validity of the transition of the human height distribution from the log-normal distribution to the normal distribution during puberty, as suggested in an earlier study [Kuninaka et al.: J. Phys. Soc. Jpn. 78 (2009) 125001]. Our data analysis reveals that, in late puberty, the variation in height decreases as children grow. Thus, the classification of a height dataset by age at this stage leads us to analyze a mixture of distributions with larger means and smaller variations. This mixture distribution has a negative skewness and is consequently closer to the normal distribution than to the log-normal distribution. The opposite case occurs in early puberty and the mixture distribution is positively skewed, which resembles the log-normal distribution rather than the normal distribution. Thus, this scenario mimics the transition during puberty. Additionally, our scenario is realized through a numerical simulation based on a statistical model. The present study does not support the transition suggested by the earlier study.

Evaluation of normalization methods for cDNA microarray data by k-NN classification

Energy Technology Data Exchange (ETDEWEB)

Wu, Wei; Xing, Eric P; Myers, Connie; Mian, Saira; Bissell, Mina J

2004-12-17

Non-biological factors give rise to unwanted variations in cDNA microarray data. There are many normalization methods designed to remove such variations. However, to date there have been few published systematic evaluations of these techniques for removing variations arising from dye biases in the context of downstream, higher-order analytical tasks such as classification. Ten location normalization methods that adjust spatial- and/or intensity-dependent dye biases, and three scale methods that adjust scale differences were applied, individually and in combination, to five distinct, published, cancer biology-related cDNA microarray data sets. Leave-one-out cross-validation (LOOCV) classification error was employed as the quantitative end-point for assessing the effectiveness of a normalization method. In particular, a known classifier, k-nearest neighbor (k-NN), was estimated from data normalized using a given technique, and the LOOCV error rate of the ensuing model was computed. We found that k-NN classifiers are sensitive to dye biases in the data. Using NONRM and GMEDIAN as baseline methods, our results show that single-bias-removal techniques which remove either spatial-dependent dye bias (referred later as spatial effect) or intensity-dependent dye bias (referred later as intensity effect) moderately reduce LOOCV classification errors; whereas double-bias-removal techniques which remove both spatial- and intensity effect reduce LOOCV classification errors even further. Of the 41 different strategies examined, three two-step processes, IGLOESS-SLFILTERW7, ISTSPLINE-SLLOESS and IGLOESS-SLLOESS, all of which removed intensity effect globally and spatial effect locally, appear to reduce LOOCV classification errors most consistently and effectively across all data sets. We also found that the investigated scale normalization methods do not reduce LOOCV classification error. Using LOOCV error of k-NNs as the evaluation criterion, three double

Rapid in situ assessment for predicting soil quality using an algae-soaked disc seeding assay.

Science.gov (United States)

Nam, Sun-Hwa; Moon, Jongmin; Kim, Shin Woong; Kim, Hakyeong; Jeong, Seung-Woo; An, Youn-Joo

2017-11-16