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Biomedical subjects

G B Hubbard

Publications and source records attributed to G B Hubbard.

At least 91 records · Page 5Linked to original sources
PubMed1987

Splenic hypertrophy and extramedullary hematopoiesis induced in male Syrian hamsters by short photoperiod or melatonin injections and reversed by melatonin pellets or pinealectomy.

Adult male Syrian hamsters either placed in a short photoperiod alone or kept in a long photoperiod and given daily afternoon injections of the pineal indole melatonin (25 micrograms) exhibited splenic hypertrophy and extramedullary hematopoiesis in addition to a marked regression in testicular weight. The testicular regression as well as the changes in spleen weight and histology could be prevented if the animals in short photoperiod were either pinealectomized or implanted subcutaneously with a pellet containing 1 mg melatonin. Female Syrian hamsters given afternoon injections of melatonin for 7 or 12 weeks had ovaries devoid of corpora lutea; additionally, these animals had reduced relative spleen weights compared to the control animals. In conclusion, it is apparent that spleen weight varies with the functional status of the gonads. Splenic hypertrophy accompanied by pineal-induced testicular regression in males may be related to splenic extramedullary hematopoiesis.

Animals↗
PubMed1987

A dose-responsive model of smoke inhalation injury. Severity-related alteration in cardiopulmonary function.

The dose responsiveness of selected physiologic indices was studied in a sheep model of smoke inhalation injury. In this model, graded severity of injury was achieved by changing the contact time with smoke (defined by "unit"), whereas other variables were kept constant. Blood gas and cardiopulmonary indices were measured in 70 sheep, including 12 controls, either 24 or 72 hours after exposure to 3, 6, 9, 12, 15, or 18 units of smoke. A 12-unit dose of smoke was fatal within 72 hours and an 18-unit dose was fatal within 24 hours. The best correlation between smoke dose and response was observed in arterial oxygen tension 24 hours after exposure. At 24 hours, most of the cardiopulmonary indices showed significant change only after a 12-unit exposure. Although the exact shape of the dose-response curve could not be defined, sigmoid or curved linear shape was suggested, reflecting the progressive deterioration.

Animals↗
PubMed1986

Endometriosis: clinical and pathologic findings in 70 rhesus monkeys.

Endometriosis was histologically confirmed in 70 female rhesus monkeys (Macaca mulatta). Severity of endometriosis was staged as minimal (14% of the monkeys), moderate (20%), or massive (66%). Clinical examination indicated masses in the abdomen and/or pelvic cavity palpable abdominally (64% of the monkeys) or rectally (93%), constipation (29%), anorexia (39%), irregular menses (17%), and radiographic evidence of abdominal soft tissue masses (38%). Pathologic findings were of intra-abdominal endometrial cyst formation (73% of the monkeys), and adhesions involving the ureters (51%), colon (66%), urinary bladder (50%), or ovaries (81%). Metastatic growth of endometrial tissue was found in 4 (6%) of the monkeys.

Animals↗
PubMed1985

Long-term inhalation toxicity of hydrazine.

Year-long intermittent exposures of rats, mice, hamsters, and dogs to hydrazine were conducted using concentrations of 0.05, 0.25, 1.0, and 5.0 ppm. Rats were held 18 months postexposure; hamsters, 1 year postexposure; mice, 15 months postexposure; and dogs, 38 months postexposure. Male and female rats exhibited dose-dependent incidences of benign nasal adenomatous polyps and smaller numbers of malignant nasal epithelial tumors after 1 year of exposure to hydrazine and 18 months postexposure holding. Nasal tumors were often associated with chronic irritation and were most frequent in male rats, with an incidence of greater than 50% in the highest exposure group. Hamsters exposed to 0.25-ppm and higher concentrations showed pathologic changes characteristic of degenerative disease, including amyloidosis. After exposure to 0.5 ppm hydrazine, hamsters developed a 10% incidence of benign nasal polyps compared to 0.5% in controls. Small numbers of colon neoplasms and thyroid parafollicular cell adenomas were found in hamsters, but only in the highest concentrations tested. Lung adenomas appeared to be marginally increased in mice exposed to 1.0 ppm hydrazine, the highest concentration tested in this species. No consistent clinical or pathological effects were seen in dogs during or after exposure to hydrazine at any concentration. Using amyloidosis as a criterion, a no-effect level was not achieved in hamsters. In rats, there appeared to be a marginal production of nasal tumors at 0.05 ppm, while mice showed no effects at 0.25 ppm. This study has demonstrated that the nasal respiratory epithelia of rats and hamsters are the most sensitive tissues to the tumorigenic action of hydrazine following inhalation exposures. This is similar to the reaction of rats to formaldehyde, another highly reactive water-soluble compound.

Animals↗
PubMed1985

Frozen section technique to evaluate early burn wound biopsy: a comparison with the rapid section technique.

The importance of early diagnosis and treatment of burn wound infection has prompted many efforts to use frozen section technique for processing burn wound biopsies, most of which have been unsuccessful. A frozen section technique which facilitates quick, reliable evaluation of biopsies was developed, and has been used in the evaluation of 169 biopsies over a period of 18 months. The frozen section technique takes 30 minutes compared with 4 hours for the rapid section method. Comparison of diagnoses made using both methods for each of the 169 biopsies produced a 96% coincidence. Each discrepant diagnosis was corrected by the rapid technique approximately 3 1/2 hours after the frozen section diagnosis. The frozen section technique is a generally accurate and rapid means of assessing the microbial status of a burn wound and diagnosing invasive infection. Permanent sections produced by rapid section technique should always be examined to confirm the frozen section diagnosis.

Biopsy↗
PubMed1985

Fungal infections of ventriculi in captive birds.

Ventricular candidiasis was the apparent cause of death in 14 of 21 captive birds, and incriminated in six others. No clinical signs were recognized in 14 of the 21 birds prior to death, and in four of the 21, no other gross or microscopic lesions were documented. Microscopic lesions included colonization of the koilin layer of the ventriculi by fungi with occasional penetration into the glandular epithelium. No conclusive pattern of infection by family of birds was detected.

Animals↗
PubMed1984

Tyzzer's disease in snow leopards.

Tyzzer's disease was diagnosed histologically in 2 litters of newborn snow leopard kittens. The gross and histological lesions were similar to those reported in domestic cats and other animals. No signs of illness was noted in either of the snow leopard dams.

Animals↗
PubMed1984

Paralysis due to a glomangioma in a Macaca mulatta.

A glomangioma at the 6-7 thoracic intervertebral space caused compression of the spinal cord with posterior paralysis in an irradiated 20-year-old female rhesus monkey (Macaca mulatta). Glomangiomas are tumors of arterial-venous shunts, are rare and have only been reported in irradiated rhesus monkeys.

Animals↗