scholarly journals Commutability of the First World Health Organization International Standard for Human Cytomegalovirus

2015 ◽  
Vol 53 (10) ◽  
pp. 3325-3333 ◽  
Author(s):  
R. T. Hayden ◽  
J. Preiksaitis ◽  
Y. Tong ◽  
X. Pang ◽  
Y. Sun ◽  
...  
Keyword(s):  
Extraction Methods ◽  
World Health ◽  
Quantitative Detection ◽  
Entire Group ◽  
Acid Extraction ◽  
International Standard ◽  
Interlaboratory Variability ◽  
Testing Center ◽  
Health Organization ◽  
Human Cmv

Quantitative detection of cytomegalovirus (CMV) DNA has become a standard part of care for many groups of immunocompromised patients; recent development of the first WHO international standard for human CMV DNA has raised hopes of reducing interlaboratory variability of results. Commutability of reference material has been shown to be necessary if such material is to reduce variability among laboratories. Here we evaluated the commutability of the WHO standard using 10 different real-time quantitative CMV PCR assays run by eight different laboratories. Test panels, including aliquots of 50 patient samples (40 positive samples and 10 negative samples) and lyophilized CMV standard, were run, with each testing center using its own quantitative calibrators, reagents, and nucleic acid extraction methods. Commutability was assessed both on a pairwise basis and over the entire group of assays, using linear regression and correspondence analyses. Commutability of the WHO material differed among the tests that were evaluated, and these differences appeared to vary depending on the method of statistical analysis used and the cohort of assays included in the analysis. Depending on the methodology used, the WHO material showed poor or absent commutability with up to 50% of assays. Determination of commutability may require a multifaceted approach; the lack of commutability seen when using the WHO standard with several of the assays here suggests that further work is needed to bring us toward true consensus.

A Collaborative Study of a Proposed International Standard for Tissue Plasminogen Activator (t-PA)

1985 ◽  
Vol 53 (01) ◽  
pp. 134-136 ◽  
Author(s):  
P J Gaffney ◽  
A D Curtis
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Collaborative Study ◽  
International Committee ◽  
World Health ◽  
Clot Lysis ◽  
Expert Committee ◽  
International Standard ◽  
Tissue Plasminogen ◽  
Health Organization

SummaryAn international collaborative study involving seven laboratories was undertaken to assess which of three lyophilised preparations might serve as an International Standard (I.S.) for tissue plasminogen activator (t-PA). Two of the preparations were isolates from human melanoma cell cultures while one was of pig heart origin. A clot lysis assay was used by all participants in the study.The data suggested that both preparations of human cell origin were comparable, in that their log dose-response lines were parallel, while that of the porcine preparation was not. Accelerated degradation studies indicated that one melanoma extract (denoted 83/517) was more stable than the other and it was decided to recommend preparation 83/517 as the standard for t-PA. The International Committee for Thrombosis and Haemostasis (Stockholm 1983) has recommended the use of this material as a standard and it has been established by the Expert Committee on Biological Standardization of the World Health Organization as the International, Standard for tissue plasminogen activator, with an assigned potency of 1000 International Units per ampoule.

Standardization of Factor VIII – IV. Establishment of the 3rd International Standard for Factor VIII: C Concentrate

1983 ◽  
Vol 50 (03) ◽  
pp. 697-702 ◽  
Author(s):  
T W Barrowcliffe ◽  
A D Curtis ◽  
D P Thomas
Keyword(s):  
Factor Viii ◽  
High Purity ◽  
Collaborative Study ◽  
World Health ◽  
Current Standard ◽  
Two Stage ◽  
International Standard ◽  
One Stage ◽  
The One ◽  
Health Organization

SummaryAn international collaborative study was carried out to establish a replacement for the current (2nd) international standard for Factor VIII: C, concentrate. Twenty-six laboratories took part, of which 17 performed one-stage assays, three performed two-stage assays and six used both methods. The proposed new standard, an intermediate purity concentrate, was assayed against the current standard, against a high-purity concentrate and against an International Reference Plasma, coded 80/511, previously calibrated against fresh normal plasma.Assays of the proposed new standard against the current standard gave a mean potency of 3.89 iu/ampoule, with good agreement between laboratories and between one-stage and two- stage assays. There was also no difference between assay methods in the comparison of high-purity and intermediate purity concentrates. In the comparison of the proposed standard with the plasma reference preparation, the overall mean potency was 4.03 iu/ampoule, but there were substantial differences between laboratories, and the two-stage method gave significantly higher results than the one stage method. Of the technical variables in the one-stage method, only the activation time with one reagent appeared to have any influence on the results of this comparison of concentrate against plasma.Accelerated degradation studies showed that the proposed standard is very stable. With the agreement of the participants, the material, in ampoules coded 80/556, has been established by the World Health Organization as the 3rd International Standard for Factor VIII :C, Concentrate, with an assigned potency of 3.9 iu/ampoule.

T26248G-transversion mutation in exon7 of the putative methyltransferase Nsun7 gene causes a change in protein folding associated with reduced sperm motility in asthenospermic men

2015 ◽  
Vol 27 (3) ◽  
pp. 471 ◽  
Author(s):  
Nahid Khosronezhad ◽  
Abasalt Hosseinzadeh Colagar ◽  
Syed Golam Ali Jorsarayi
Keyword(s):  
Protein Folding ◽  
Sperm Motility ◽  
Protein Function ◽  
Direct Sequencing ◽  
Protein Structures ◽  
Single Strand Conformation Polymorphism ◽  
Extraction Methods ◽  
World Health ◽  
Transversion Mutation ◽  
Health Organization

The NOP2/Sun domain family, member 7 (Nsun7) gene, which encodes putative methyltransferase Nsun7, has a role in sperm motility in mice. In humans, this gene is located on chromosome 4 with 12 exons. The aim of the present study was to investigate mutations of exon 7 in the normospermic and asthenospermic men. Semen samples were collected from the Fatemezahra IVF centre (Babol, Iran) and analysed on the basis of World Health Organization (WHO) guidelines using general phenol–chloroform DNA extraction methods. Exon 7 was amplified using Sun7-F and Sun7-R primers. Bands on samples from asthenospermic men that exhibited different patterns of movement on single-strand conformation polymorphism gels compared with normal samples were identified and subjected to sequencing for further identification of possible mutations. Direct sequencing of polymerase chain reaction (PCR) products, along with their analysis, confirmed C26232T-transition and T26248G-transversion mutations in asthenospermic men. Comparison of normal and mutant protein structures of Nsun7 indicated that the amino acid serine was converted to alanine, the structure of the helix, coil and strand was changed, and the protein folding and ligand binding sites were changed in samples from asthenospermic men with a transversion mutation in exon 7, indicating impairment of protein function. Because Nsun7 gene products have a role in sperm motility, if an impairment occurs in exon 7 of this gene, it may lead to infertility. The transversion mutation in exon 7 of the Nsun7 gene can be used as an infertility marker in asthenospermic men.

Pneumonia Detection Using Deep Learning Architectures

2020 ◽  
Vol 17 (12) ◽  
pp. 5535-5542
Author(s):  
Purohit Om Hemantkumar ◽  
Rakshit Lodha ◽  
Meghna Bajoria ◽  
R. Sujatha
Keyword(s):  
Feature Extraction ◽  
Imaging System ◽  
Extraction Methods ◽  
World Health ◽  
X Rays ◽  
Wavelet Frame ◽  
Training Models ◽  
Wavelet Frame Transform ◽  
Health Organization ◽  
Learning Architectures

Pneumonia is an infection caused by bacteria and viruses. It can shift from mellow to serious cases. This disease causes severe damages to the lungs since they fill with fluids. This situation causes difficulty in breathing. It further prevents oxygen to reach the blood. Pneumonia is diagnosed with the help of a chest X-rays, which can also use in the diagnosis of diseases like emphysema, lung cancer, and tuberculosis. According to WHO (World Health Organization (WHO). 2001. Standardization of Interpretation of Chest Radiographs for the Diagnosis of Pneumonia in Children. p.4.), Chest X-rays, at present, is the best available method for detecting pneumonia. Feature extraction methods like DiscreteWavelet Transform (DWT),Wavelet Frame Transform (WFT), andWavelet Packet Transform (WPT) can be used followed by any classification algorithm. In this paper, models like Squeezenet, DenseNet, and Resnet34 have been used for image recognition. In our system, the medical images were taken from Kaggle database and were recorded using a suitable imaging system. The images retrieved were then considered for input for the system where the images go through the various phases of image processing like pre-processing, edge detection and feature extraction. Later, a variety of training models are applied to know which model offers the highest accuracy.

scholarly journals Genomic Sequence of the WHO International Standard for Hepatitis A Virus RNA

2018 ◽  
Vol 6 (19) ◽  
Author(s):  
Adrian Jenkins ◽  
Rehan Minhas ◽  
Clare Morris ◽  
Neil Berry
Keyword(s):  
Hepatitis A ◽  
Genomic Sequence ◽  
Hepatitis A Virus ◽  
World Health ◽  
Design Development ◽  
Noncoding Regions ◽  
International Standard ◽  
Virus Rna ◽  
Health Organization ◽  
Nucleic Acid Assays

ABSTRACT The World Health Organization (WHO) international standard for hepatitis A virus (HAV) RNA nucleic acid assays was characterized by complete genome sequencing. The entire coding sequence and noncoding regions were assigned HAV genotype IB. This information will aid the design, development, and evaluation of HAV RNA amplification assays.

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