Correlation between heart disorders and concentrations of directly measured atrial natriuretic peptide in plasma

We used new commercially available direct radioimmunoassay to measure human atrial natriuretic peptide (h-ANP) in plasma from 48 individuals who were being evaluated for left and right ventricular function. For 13 healthy individuals with normal ventricular function these concentrations ranged up to 54 ng/L. Measurements of h-ANP clearly differentiated between normal subjects, patients with coronary artery disease, and patients who had undergone orthotopic heart transplantation (ANOVA P less than 0.0001, significant differences between all groups)--all showing normal ventricular function at rest. There was a strong negative correlation (r = -0.64, P less than 0.001) between left ventricular ejection fraction and h-ANP concentrations in plasma of patients with proven coronary artery disease, patients with cardiomyopathy, and healthy individuals. Results by the present method and methods involving extraction of the sample correlated well. Evidently the direct assay of h-ANP in plasma yields information that could be used to help evaluate heart disorders and other pathophysiological conditions causing increased h-ANP concentrations in plasma.

Evaluation of radioimmunoassays: comparison of dose interpolation calculations by four parameter logistic and spline functions

Two computerized methods for dose interpolation calculation were compared. Generated data sets with a known coefficient of variation as well as laboratory RIA data were analysed. The four parameter logistic method, which is based on an approximation of the mass action law, performed better than the Spline method, a procedure which makes no a priori assumptions about the data. Correct weighting of the data was important for obtaining satisfactory fits. The determination of the response error relationship proved to be the most satisfactory approach in obtaining suitable weighting factors.

Experimental infection of calves with an adenovirus isolated from sheep and related to bovine Adenovirus type 2 I. Clinical and virological studies

Colostrum deprived calves were experimentally infected with an adenovirus isolated from sheep and related to bovine adenovirus type 2. The calves showed respiratory symptoms and mild diarrhoea from the third day after infection. Laboratory tests revealed the development of leucopenia, lymphopenia, a drop of the pH of the urine and the appearance of pathological changes in the urine. The animals shed the virus in their nasal discharge, faeces and urine. Comparing the clinical and virological findings with the previous experimental infection of lambs it is concluded, that this type of adenovirus is similarly pathogenic for the two ruminant species.