Biomedical subjects
Publications and source records attributed to J Halperin.
A 41-year-old woman with Maroteaux-Lamy syndrome developed spastic tetraparesis due to a compressive cervical myelopathy. There was substantial improvement following laminectomy and excision of the markedly thickened dura. Light and electron microscopic studies showed extensive accumulations of balloon cells in the dura.
The continuous infusion of glucose (1 mg/kg/min) via the carotid artery in anesthetized dogs produces a biphasic pattern of insulin secretion. The first peak reaches a maximum 3 min after glucose infusion and drops to basal level at 7 min. As long as the glucose infusion persists a slow and mantained increase in insulin level in the pancreaticoduodenal vein can be observed. The same amount of glucose infused in the general circulation via the jugular vein provoked a different pattern of insulin secretion. Cerebral glucose infusion to vagotomized dogs also produced a two phase response to insulin secretion, but the levels reached in the first phase were lower that those observed in the normal dogs. The infusion of glucose, via the jugular vein, in vagotomized dogs, failed to induce any change in plasma insulin levels. Our data suggest that a glucose load to the brain induces pancreatic insulin secretion mediated partially by the vagus nerves. These results are also compatible with the hypothesis that a humoral factor could be involved in the pancreatic response.
Injection of Salmonella typhosa endotoxin into either CF1 or C57bl/6J mice leads to prompt increases in serum colony-stimulating factor (CSF). Repeated injections of endotoxin result in a dose-related hyporesponsiveness or tolerance to this effect. Tolerance is seen after either intravenous (i.v.) or intraperitoneal (i.p.) routes of administration or challenge and occurs after one to two preinjections. Cross-tolerance to heterologous endotoxin (Escherichia coli) was also shown. This cross-tolerance is complete immediately after cessation of preinjections, but partial at later time intervals. Levels of a serum inhibitor of colony growth were decreased in tolerant mice, although this decrease is not statistically significant. Tolerant mice injected with endotoxin release granulocytes from the bone marrow normally, in spite of the absence of a CSF response. This suggests that neutrophil releasing activity (NRA) and CSF are separate entities. A marked marrow granulocytic hyperplasia develops after 7 or 20 days of endotoxin injections, despite the tolerance to the CDF-elevating effect of endotoxin. This granulocytic hyperplasia could still be mediated by serum CSF increases. A negative medullary feed-back secondary to the repetitive release of marrow granulocytes, however, is an equally plausible mechanism for the stimulation of granulocyte production. It is also possible that the decrease in serum inhibitors played a role in the sustained increase in granulopoiesis seen here.