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Biomedical subjects

R M Harrison

Publications and source records attributed to R M Harrison.

125 records · Page 7Linked to original sources
PubMed1975

A review of reproductive patterns in new world monkeys.

A review of the literature indicated that most of the information of reproductive patterns in New World monkeys has been gained from studies on the squirrel monkey. This species has been successfully bred in both indoor and outdoor colonies. Both sexes exhibit seasonal cyclicity that appears to be influenced by a number of environmental conditions. Reports indicated that most of the other New World species have been bred in captivity, most commonly in zoos. The scientific data on these species are sparse, usually obtained from small groups or individual animals.

Alouatta↗
PubMedDate not supplied

Testicular blood flow and fluid dynamics in monkeys with surgically induced varicoceles.

The blood flow rates and ability to remove an added fluid load were studied in the testes of monkeys with surgically induced varicoceles and in sham-operated control monkeys. These studies were conducted to verify a proposed mechanism by which varicocele may cause testicular and spermatogenic damage. Analyses of the data indicated that, at four months after induction, the testes of monkeys with varicocele were less able to remove a perfused fluid load and that, at five months, the blood flow was significantly less in the testes of these animals. The effects were most pronounced in the left testes of the monkeys with varicocele. Blood flow values calculated were: control, right--9.66 ml X 100 g-1 X min-1; control, left--10.42 ml X 100 g-1 X min-1; varicocele, right--7.73 ml X 100 g-1 X min-1; varicocele, left--5.04 ml X 100 g-1 X min-1. These data suggest a new theory, that increased pressure on the venous side of testicular capillary beds in subjects with varicocele may decrease blood flow and cause testicular damage.

Animals↗
PubMedDate not supplied

Delayed myeloradiculopathy produced by spinal X-irradiation in the rat.

Rats were subjected to 3,500 r of X-irradiation in a single dose while breathing oxygen at 1 ATM pressure. Comparison was made between the delayed effects of irradiating thoracic, lumbar, and the cauda equina fields. The lumbar field involved the alpha-motoneurons and spinal roots supplying the sciatic nerve, while the cauda equina field involved these spinal roots but spared the alpha-motoneurons in the spinal cord. Thoracic irradiation produced paraplegia after an interval of 127-150 days. In the irradiated zone, the spinal cord was severely damaged, but the thoracic spinal roots were spared. Lumbar irradiation produced paraplegia after an interval of 83-211 days. In the irradiated zone, the alpha-motoneurons were largely spared, the spinal cord showed mild to moderate white matter damage, but the most severe damage was of the lumbosacral spinal roots. The posterior roots were more affected than the anterior. In longer interval cases the degeneration of the roots appeared to be due to focal devitalization. Evidence is advanced that root degeneration had been progressing for at least 4 weeks before the onset of paraplegia. In the cauda equina series the lumbosacral spinal root changes were similar to those in the lumbar series. This study indicates that different levels of the neuraxis have different degrees of susceptibility to X-irradiation. The thoracic cord appears more susceptible than the lumbosacral; the lumbosacral roots appear more susceptible than the thoracic; the posterior roots are more susceptible than the anterior. These findings may have relevance to the study of radiation damage in man, even though the dose schedule used in this experimental study differs greatly from that used for radiotherapy.

Animals↗