Ultrafiltered Serum Research Articles

Chemotactic attraction of infective hookworm larvae of Ancylostoma caninum by a dog serum factor.

Infective hookworm larvae of Ancylostoma caninum showed chemotaxis on agar plates in a dog serum gradient. This chemotactic behaviour remain unaltered using an ultrafiltrated serum fraction with a molecular weight less than 500. Gelfiltration of this ultrafiltrated fraction revealed a factor with a molecular weight of 480 causing chemotaxis. The chemotactic activity of the factor was destroyed after a pronase treatment. We conclude that the factor could be a polypeptide.

New rapid kit for determining calcium in serum and urine evaluated.

We describe the performance of a colorimetric reagent kit (Diagnostic Systems Laboratories, Inc., Webster, TX 77598) for measuring calcium directly in urine, serum, and ultrafiltered serum, and compare the results with those obtained with atomic absorption spectrophotometry. The CV for within-run precision was 2.8 and 2.1% for urine and whole serum, respectively (n = 10 each). Between-run precision for urine, whole serum, and ultrafiltered serum was 1.9, 1.6, and 2.2%, respectively (n = 8 to 10). Analytical recovery of added calcium from three different urine and serum specimens, to which three different concentrations of calcium had been added, was 101.9 (SD 0.3%) for urine and 100.9 (SD 0.2%) for serum. Assay of 30 urine specimens, 15 ultrafiltered serums, and 20 whole serums by both the kit and atomic absorption spectrophotometry demonstrated correlation coefficients of 0.993, 0.828, and 0.751, respectively. Mg2+, hemolysis, or lipemia does not interfere. Compared with atomic absorption spectrophotometry, the calcium kit procedure is rapid and simple.

Alteration of oxidative phosphorylation in uremia.

The effect of ultrafiltrate of uremic serum upon the oxygen consumption of rat liver mitochondria was studied. Oxygen consumption in the absence of adenosine diphosphate (State 4) was increased by the addition of ultrafiltered serum of uremic patients, causing decrease of P/O ratio and respiratory control ratio, indicating the uncoupler action of uremic serum. Such uncoupler action was noted when succinate was used as the substrate, and also when α-ketoglutarate was used as the nicotinamide adenine dinucleotide-linked substrate. The mitochondrial respiration in the presence of adenosine diphosphate (State 3) was decreased, suggesting the inhibitory action of uremic serum on energy transfer. Oxygen consumption after 20 minute incubation with uremic serum showed the decrease in either state, leaving ground for the presence of inhibitory action against electron transport. Similar results were obtained in liver mitochondria of rats in acute renal insufficiency caused by bilateral nephrectomy. Based on these facts, the nature of metabolic inhibitors in uremic serum was discussed.