External quality assessment of RIA for thyroid related hormones

An external quality assessment was conducted for RIA of thyroid related hormones. Thirtyfive laboratories (35 for T₄, 34 for T₃ and 23 for TSH) from different parts of country participated in the programme. Twentyfour samples (16 pools: 5 simple and 11 manipulated pools) in 8 batches, 3 per batch per month were sent for analysis of T₄, T₃ and TSH. Some of the samples were repeated 3 times at different occasions to assess the imprecision of the laboratory. The overall mean percent CV obtained for T₄, T₃ and TSH were 22.7, 36.32 and 52.38 respectively. The recovery for added T₄ was 86.73% while that for T₃ was 117.4%. A large variation was obtained for recovery of TSH. For T₄ estimations, 13 laboratories had a desirable performance i. e. bias less than ±10.0% and variability of bias (VB) and imprecision (IP) less than 15.0%. None of the laboratories had a desirable performance for T₃ or TSH. The number of laboratories with acceptable performance i. e. bias between ±10.0–15.0%, VB and IP between 20.0–25.0% for T₄, T₃ and TSH were 4, 3 and 0 respectively. The number of laboratories which required attention (bias between ±15.0–20.0%; VB and IP between 20.0–25.0%) were 5,7 and 1 respectively. The unacceptable results with larger bias, VB and IP for T₄, T₃ and TSH were 6, 18 and 17 respectively. Our results are in general agreement that the performance of T₄ assay is better than T₃ and both in turn are much better than TSH. Quantitation of circulating thyroid hormones (TH) viz. tri-iodothyronine (T₃), thyroxine (T₄) and thyroid stimulating hormone (TSH), which form the largest percentage of hormones estimated in a clinical laboratory is mainly done by radio-immunoassay (RIA) procedures. The reliability and reproducibility of these assays are generally monitored by using internal quality control (IQC) samples in every assay batch. Thus, the IQC provides information whether the assay results are satisfactory and can be released. However, external quality assessment (EQA) is a procedure whereby an external agency undertakes evaluation of the quality of an analytical service by providing samples for analysis to individual laboratories performing the assay. The data gathered is analysed collectively. EQA therefore provides a means by which performance of a laboratory is assessed in relation to other laboratories and matching the assay unbiased by removing systematic error, if present. This is important since RIA procedure involves several steps (collection and storage of samples, quality of the reagents, procedure followed for performance of an assay, counting equipment used and the mode of the data analysis) and therefore prone to systematic errors. We therefore undertook the EQA programme for assessment of thyroid related hormones as a joint collaborative project of Bhabha Atomic Research Centre, India and International Atomic Energy Agency.     

A general framework for progressive point-sampled geometry

INTRODUCTION With the recent advances in 3D digital photog- raphy and scanning technology, unstructured dense point sets sampled from the surfaces of physical ob- jects have become a new representation of geometric shapes. The shape thus specified is usually referred to as point-sampled geometry (Amenta and Kil, 2004; Liu et al., 2004; Pauly et al., 2003; Zwicker et al., 2002), in which two key techniques are involved: (1) The raw point data P is discrete in nature while the physical ob…     

新能源节能动力汽车及电工电子设计研发

本文介绍了新能源节能动力汽车及电工电子设计研发,从汽车电工电子设计技术等方面较深入地探讨了汽车节能的方法,论述了研发新能源节能动力汽车与技术动向。相信未来有更节能、更环保、更先进的动力机汽车出现。     

Association of Interleukin-6 and Myeloperoxidase with Insulin Resistance in Impaired Fasting Glucose Subjects

Impaired fasting glucose (IFG) is a high risk subclinical condition for the progression of type 2 diabetes mellitus and the hyperglycemia seen in this condition is because of the development of insulin resistance (IR). Obesity, inflammation, oxidative stress and many other factors have been implicated in development of IR in type 2 diabetes mellitus and its successive complications. Current study was aimed to ascertain the correlation of inflammation and oxidative stress markers [interleukin-6 (IL-6) and myeloperoxidase (MPO)] with IR in subjects with IFG. In this study, 80 subjects (40 IFG, 40 healthy controls) aged 25–45 years were selected based on their fasting plasma glucose (FPG) values and clinical history. Serum insulin, IL-6 and MPO were estimated by ELISA method and IR was calculated using Homeostatic Model Assessment Index 2 (HOMA 2) calculator. Pearson’s correlation coefficient and independent sample ‘t’ test were used for statistical analysis. IL-6 and MPO were found to be significantly elevated in IFG group and both correlates significantly with IR (r 0.413, r 0.645). Only MPO had significant correlation with FPG (r 0.388). In conclusion, the association of altered levels of IL-6 and MPO with IR are suggestive of a role of inflammation and oxidative stress in the initiation and progression of IR in individuals with IFG.     

Sialic acid in cardiovascular diseases

Sialic acid, the acylated derivatives of 9-carbon sugar neuraminic acid, present as terminal component of oligosaccharide chains of many glycoproteins and glycolipids, has been recognized to be involved in the regulation of a great variety of biological phenomena. Studies have shown that serum sialic acid predicts both coronary heart disease and stroke mortality and reflects the existence or activity of an atherosclerotic process. Most of the studies have shown an elevation in serum sialic acid concentration in coronary heart disease and a positive correlation between the raised serum sialic acid and the severity of the coronary lesions is observed. However, a few contradictory reports are also available. Racial differences in serum sialic acid have also been reported and correlated with international differences in the prevalence of atherosclerosis. Reduced sialic acid content of platelets, erythrocytes and lipoproteins may play important role in the pathogenesis of atherosclerosis. Elucidation of the mechanism of alternation in sialic acid concentration may throw more light on its potential clinical utility. Hence more studies are needed to designates sialic acid as a cardiovascular risk factor/marker.     

A new representation of orientable 2-manifold polygonal surfaces for geometric modelling

INTRODUCTION Polygonal surface has become ubiquitous due to its efficient representation of highly detailed geomet- ric objects with arbitrary topological type. In real-world simulation and analysis, a 3D physical object is modelled as a closed subset in ú3 bounded by a connected, compact and orientable 2D manifold. For algorithmically describing orientable 2-manifold polygonal surfaces, the practical data structure should not only easily check manifold property and topo- logical consist…