A simple, cost-effective quality assurance model for measurement of lipids in a large epidemiological study.

Background. Laboratory measurements are an integral part of epidemiological studies in cardiovascular disease. Standardization and quality assurance is of utmost importance in the context of multicentre studies. Methods. We evaluated a simple and cost-effective method of quality assurance for measurement of total cholesterol, high density lipoprotein (HDL) cholesterol and triglycerides in a study involving 10 centres. Three methods for quality assessment were used for the study that involved measurement of cholesterol, triglycerides and HDL cholesterol and included internal quality control, external quality control and 10% repeat analysis in addition to a uniform standardized protocol developed for the 10 centres. External quality control material was prepared and circulated by the coordinating laboratory. Results. External quality control material was distributed 20 times during the study. The mean variance index suggested a substantial improvement in the performance of participating laboratories over a period of time for cholesterol and triglycerides. This was also evident in the improvement in per cent technical error as a measure of bias and a higher correlation between replicates of samples analysed in the coordinating laboratory and the participating centres for cholesterol, triglycerides and HDL cholesterol. Conclusion. A cost-effective quality assurance model for laboratory measurement using local capacities was developed and implemented in a multicentre epidemiology study. Such a programme would be useful for developing countries where cost-cutting is important.

Endomyocardial fibrosis is associated with selective deposition of type I collagen.

BACKGROUND: Endomyocardial fibrosis is a distinct form of heart disease leading to restrictive ventricular filling and cardiac failure. The disease is characterized by a marked thickening of the endocardium due to the deposition of dense fibrous tissue composed of wavy bundles of collagen. Changes in collagen composition and an abnormal increase in its concentration result in a stiffer myocardium and ventricular diastolic dysfunction. The nature of cardiac collagens and the relative proportions of collagen types in endomyocardial fibrosis have not been documented in the literature. METHODS AND RESULTS: This study analyzed collagen composition in the cardiac tissues of 13 patients with endomyocardial fibrosis and 6 individuals who were the victims of traffic accidents or suicidal deaths and did not have any heart disease. We estimated the relative proportions of types I and III collagen after pepsin digestion of the tissue and separation of the emerging peptides by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The mean type I:III collagen ratio was 0.51+/-0.06 in normal individuals, and 0.93+/-0.43 in patients with endomyocardial fibrosis (p<0.05). The alteration in the type I:III collagen ratio was due to a disproportionate increase in type I collagen. CONCLUSIONS: The results indicate that a selective increase in type I collagen may contribute to the impaired diastolic distension of the ventricles in patients with endomyocardial fibrosis.

A simplified method for culture of human fetal heart tissue.

Human fetal heart tissue obtained consequent to suction termination of pregnancy between 6 and 12 weeks of gestation were cultured as explants and maintained in a viable state, with spontaneous contractions up to 75 days. Ultrastructural morphology of the explant revealed that the cells remained healthy up to 21 days in culture. The model can therefore be used for experimental studies during the first 3 weeks in culture.