Medical examiners' seminar looked at mysteries surrounding sudden death

Medical examiners in Nova Scotia recently attended their first-ever seminar concerning the skills, challenges and techniques their jobs require. It was welcomed by the physicians, most of whom are family physicians with little training in the investigation of sudden death.     

An outdoor biophotolytic system using the cyanobacterium Anabaena cylindrica B629

The cyanobacterium Anabaena cylindrica B629 was suspended in small glass beds and incubated in a gas-tight glass vessel outdoors under a gas atmosphere comprising carbon monoxide (0.2%), acetylene (5%), oxygen (6.5%), and nitrogen. The solution phase initially contained sodium bicarbonate (10mM) at pH 7. Under these conditions the organism continuously produced hydrogen gas for over three weeks. The temperature of the culture was maintained below 30°C and minimum night temperatures were recorded. The vessel was covered by a shadecloth, which reduced the natural illumination by approximately 70%. The system is an alternative to those requiring the strict absence of oxygen and little nitrogen, and requires virtually no attention during the incubation period.     

A new family of 2-hydroxyacid dehydrogenases

The NADH-dependent hydroxypyruvate reductase from cucumber and the pdxB gene product of E. coli display significant homology to E. coli D-3-phosphoglycerate dehydrogenase. In contrast, these proteins do not display much similarity with other oxidoreductases or with other 2-hydroxyacid dehydrogenases in particular. On the basis of their relatedness and the structure of their substrates, these three enzymes constitute a new family of 2-hydroxyacid dehydrogenases distinct from malate and lactate dehydrogenase.     

Characterization of the major immunogen in the excretory-secretory products of exsheathed third-stage larvae of Trichostrongylus colubriformis

The excretory-secretory products of exsheathed third-stage larvae of Trichostrongylus colubriformis conferred some protection to guinea pigs against homologous challenge. A glycoprotein with an apparent molecular mass of approximately 94 kDa was the dominant immunogen in post-exsheathment products. Immunoblots revealed IgG antibodies to this glycoprotein in sera from multiply-infected guinea pigs and some sheep, and in sera of guinea pigs after three truncated infections which had been restricted by anthelmintic treatments to development of the third parasitic stage. IgA antibodies to this protein were also found in intestinal lymph of a naturally infected sheep. Fluorescent antibody studies indicated that this 94 kDa component was associated with cells in the central body cavity of third-stage larvae, but was absent from fourth-stage larvae or adult worms. Fractionation and protection assays in guinea pigs revealed that while the native and aggregated 94 kDa protein conferred some host protection, it was not the only protective component of the excretory-secretory products of exsheathed third-stage larvae of T. colubriformis.     

Studies on the immediate and delayed leucocytosis elicited by brief (30-min) strenuous exercise

Eight healthy male volunteers exercised for two 30-min sessions starting 3 h apart on an electronically braked cycle ergometer at a work load (mean 155.9 W, SD 33.4 W) which required an oxygen consumption that was 70% of their maximal rate of oxygen uptake. Venous blood samples were taken through an indwelling cannula over a period of 6 h beginning shortly before the first bout of exercise and were analysed for routine haematological parameters and for lactate, noradrenaline, adrenaline and cortisol. Both bouts of exercise induced an immediate leucocytosis due to rises in lymphocytes and neutrophils but only the first exercise bout induced a substantial delayed neutrophilia. In at least five subjects, changes in lymphocyte and platelet numbers were correlated (Spearman's rank procedure, P less than 0.05) with simultaneous changes in the plasma concentrations of lactate, noradrenaline and adrenaline over the 6-h period studied. Increases in the plasma concentration of cortisol due to exercise correlated positively with the percentage changes in neutrophil numbers at 3 h and 6 h. These results are consistent with the suggestion that the immediate and delayed leucocytosis induced by exercise are mediated respectively by catecholamine and by cortisol.     

Endocrine and metabolic responses of the collared peccary (Tayassu tajacu) to immobilization with ketamine hydrochloride

Serial physiological responses were examined for 150 min from captive collared peccaries during immobilization with ketamine hydrochloride. Rectal temperatures decreased significantly (P less than 0.01) during anesthesia. Serum concentrations of total proteins, albumin, cholesterol, alanine aminotransferase, and calcium declined significantly (P less than 0.05) during the first 45 min post-immobilization before stabilizing. Concentrations of lactate dehydrogenase and alkaline phosphatase in sera showed similar but nonsignificant (P greater than 0.05) trends. Inorganic phosphorus and aspartate aminotransferase concentrations increased significantly (P less than 0.05) throughout the trial. Concentrations of serum glucose and glucocorticoid during the immobilization period were highly variable between individuals. Serum electrolytes, urea nitrogen, creatinine, gammaglutamyl transferase and progesterone were not significantly (P greater than 0.05) affected by immobilization. Elevations in serum testosterone were noted. Results indicated appropriate sampling times relative to immobilization for assay of particular serum biochemicals and steroid hormones during investigations of the physiology of the collared peccary.