Biomedical subjects
Publications and source records attributed to J Benfield.
In Australia, the suicide rate for adolescent males has doubled during the seventies; that for adolescent girls remains unchanged. For the remainder of the male population the rise is paralleled only by men in their twenties. Otherwise, for middle-aged men the suicide rate remains about the same and in the older age groups is falling.
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Both normal human serum and supernatant from explanted malignant tumors contained a heat-stable low-molecular-weight factor that inhibited monocyte activation in vitro. In contrast, serum from individuals with solid tumors enhanced monocyte activation. It is suggested that the systemic activation of monocytes that occurs in malignant disease may be an appropriate host response but that successful tumors may continue to grow because they subvert the normal physiological signal for inhibition of macrophage activation.
Gastrointestinal anatomy and function has been studied prospectively in 12 patients undergoing jejunoileal bypass surgery in order to investigate the adaptive response of the intestinal mucosa. The total thickness of the jejunal mucosa did not change after surgery, but the crypts became relatively deeper, suggesting a more rapid turnover of gastrointestinal cells. The absorption of oxalate was depressed in the immediate postoperative period but had improved toward preoperative levels by 6 months. Vitamin B12 absorption also declined postoperatively, and increased thereafter in the patients with an end-to-end jejunoileostomy, but showed a much smaller recovery in the group with an end-to-side anastomosis. The cholesterol concentration (lithogenicity) of the duodenal bile rose by 30% in the first 3 weeks after surgery, but had returned to preoperative levels by 6 months. The segmental absorption of glucose across the jejunum declined after surgery. Caloric intake also declined, whether measured as the quantity of food that patients elected to eat over a 24-hr period, or as the quantity of a liquid lunch which they consumed over a 20-min period. The level of basal gastric acid was increased postoperatively but the maximal output after histamine stimulation was not. The gastrin response to a standard liquid meal was also significantly increased after surgery. Enteroglucagon secretion showed an increase in 3 weeks and a further increase by 6 months after intestinal bypass surgery. The significance of these changes to intestinal adaptations is discussed.
Radiation therapy to either mediastinum or pelvis causes a rapid decrease in circulating lymphocytes of both B and T types and in addition an impairment in the function of the remaining lyphocytes, as measured by their ability to proliferate in response to mitogens. The acute depression is short-lived. Substantial recovery is apparent within 3 wk after cessation of therapy; however, most patients show a modest, chronic depression in both numbers and functional capacities of circulating lymphocytes. T cells are somewhat more sensitive than B cells, but both are affected. Irradiation of the thymus per se seems to have little influence on the acute changes which occur, as patients receiving pelvic and mediastinal (including thymic) radiotherapy show a similiar degree of lymphopenia and depression of lymphocyte responsiveness.