PubMed Health⌕ Search

Biomedical subjects

G Bryson

Publications and source records attributed to G Bryson.

At least 55 records · Page 3Linked to original sources
PubMed1978

Long-term effects of adrenal and ovarian ablation on the regulation of energy exchange in the female rat.

Body weights of female rats in six postsurgical groups were observed over 120 days. Ovariectomy increased body weight as compared with controls, whereas adrenalectomy decreased it. Weights of animals that were both ovariectomized and adrenalectomized were intermediate between those of controls and adrenalectomized groups. The body weights of adrenalectomized rats that were not salt dependent resembled those of animals that had not undergone adrenal surgery. Plasma levels of corticosterone and progesterone were determined by radioimmunoassay. Adrenalectomy that resulted in salt dependency, whether or not in conjunction with ovariectomy, markedly decreased corticosterone levels. Ovariectomy alone or in conjunction with adrenalectomy decreased progesterone levels. The increased body weight of the group that was both ovariectomized and adrenalectomized over the group that was only adrenalectomized suggests that the decreased body weight generally observed for adrenalectomized animals may relate to mechanisms of voluntary regulation rather than frank debilitation.

Adrenalectomy↗
PubMed1978

Species differences in blood serum reserves for cholesterol solubilization.

The capacity of male human, rat, and guinea pig sera to solubilize cholesterol was measured by in vitro equilibration. Evaporation, adsorption by filter paper and/or cholesterol, and protein denaturation were controlled by measuring serum protein and albumin along with cholesterol contents. The uptake of cholesterol for the above groups was 23.1 +/- 1.2, 18.9 +/- 1.8, and 10.7 +/- 0.8 mg/100 ml, respectively. The percentage increases over initial serum cholesterol were 11.9 +/- 0.9, 18.7 +/- 2.0, and 35.1 +/- 2.7%, respectively. The uptake of cholesterol by serum per se without involvement of either releasing or target tissues appears to be an irreversible and protective solubility phenomenon; no cholesterol plates were deposited upon the undissolved solute or precipitated on addition of triglyceride to cholesterol-saturated serum. The omnivorous human and rat had a greater absolute reserve for solubilizing cholesterol, but the herbivorous guinea pig a greatly enhanced relative (% increase) reserve.

Animals↗
PubMed1977

Intraperitoneal foreign body reaction in rodents.

In five experiments with female Marsh mice and male and female Evans rats, open-end cylinders of tin were implanted intraperitoneally with litter mates serving as surgical controls. The experiments were terminated 18-24 months later. The long-term local intraperitoneal foreign-body reaction with some cylinders remaining unanchored, frequent failure to develop a fibrous capsule at the outside of the tin cylinder, and a degree of lympho-histiocytic involvement and adenomatous hyperplasia in the fibrosis within the tin cylinder differed from the foreign-body reaction at the subcutaneous site characterized by avascular, cell-poor fibrosis with fibroblasts. In all the implanted rat series, a significant number of local sarcomas, 30-50% of which metastasized, developed with none in the corresponding controls. The incidences of spontaneous lymphoid tumors were decreased or not increased for the tin-implant series as compared with controls. This indicated that the local solid-state carcinogenic process was only partially, if at all, dependent upon the cell type (lymphocyte) that demonstrated a spontaneous inherently malignant potential.

Animals↗
PubMed1977

Short- and long-term effects of a massive dose of 6-OH-DA upon marsh mice.

Single, sublethal subcutaneous doses of 6-hydroxydopamine (6-OH-DA) were given to young adult male and female Marsh mice. The ability of 6/8 males to sire 15 or more days later was not abolished. Of 10 females dosed during pregnancy, 6 failed to deliver and lost substantially in body weight. Of the 4 that delivered, 2 cannabalized their young. The offspring of the 6-OH-DA-dosed fathers and mothers showed no gross anatomical defects nor lessened survival rates. Confrontation of 6-OH-DA-dosed males with control males as pairs demonstrated increased anal sniffing as compared with control-pair confrontation. In a long-term series with males, liver anomalies including tumor development were demonstrated for 6-OH-DA. Lymphoid tumor induction was not affected. However, 3 local fibrosarcomas and 1 intrasorbital giant cell sarcoma arose. A sublethal dose of L-dopa had no lasting effect on male mouse aggression nor on other behavioral manifestations that would implicate 6-OH-DA formation as a metabolic route.

Aggression↗
PubMed1976

Toxicologic studies of tin needles at the intrathoracic site of mice.

Male Marsh mice which received a single intrathoracic injection of 4 mg of tin needles at 3 months of age were compared with controls given isotonic saline. The form and size of most of the tin needles were similar to those of asbestos needles which produced mesotheliomas and lung neoplasms in rodents. Water and food intake was markedly reduced for 24 hrs after the injection of tin. Survival rates (followed for 19 months), pathology of the bladder, liver, and kidney, as well as local and general cancer development were not adversely associated with the tin treatment as compared with the tin treatment as compared with controls. The local reaction to the tin included giant cell phagocytosis, nodular fibroplasia, and capillary formation. The failure of the tin needles to induce local neoplasms may relate to their high density as compared with silicates and/or their lack of the unique potential of the silicate particles to stimulate avascular fibrosis.

Animals↗
PubMed1975

Male mouse aggression as a pharmacologic model.

At 5 to 8 months of age the fighting and tail-rattling of male Marsh mice during paired confrontations was significantly greater for isolated than for mice prehoused in groups of males or in groups of one male with females. The differences were not significant for treatment effects tested in a similar manner with mice 11 to 12 months of age. At 5 months of age, mounting behavior of pregrouped males on paired confrontation was significantly less than that of isolated males. Paper towels instead of pine shavings for bedding abolished test-fighting for isolated mice. In any model with randomly sampled groups, an inherently highly aggressive mouse (killer) required to be eliminated from the grouped series, is not detected in the isolated series. These considerations challenge the use of isolated male mice as a pharmacologic model for evaluating behavior-modifying drugs. A four-fold difference in the area of prehousing cages of isolated males did not influence aggressive behavior. Fights correlated with tail-rattling; r equals 0.93 over the 14 series studied.

Age Factors↗
PubMed1975

Cholesterol plate deposition in a pathological transport environment.

Triglycerides separated from human serum lipoprotein or triolein converted cholesterol needles to plates on equilibration in isotonic saline. Cholesterol needles equilibrated with human clear or lipemic plasma or serum were not converted to plates unless olive oil or triolein was added. Plasma phospholipid permitted and sodium lauryl sulfate (0.1-10%) prevented formation of plates from cholesterol needle-saturated olive oil in water at 38 degrees C. Cholesterol liquid crystals, formed from needles dispersed in aqueous plasma phospholipid, changed to plates on dilution with water. The cholesterol content of lipemic and high-, normal-, or low-cholesterol sera, equilibrated with cholesterol plates at 38 degrees C, was not significantly altered. In rats and mice the mobilization of injected cholesterol needles at the intrathoracic site manifested a sex-species difference. In the pathological deposition of cholesterol plates, a breakdown of a defense mechanism in plasma involving noncovalent binding of triglyceride with phospholipid and protein is indicated.

Animals↗
PubMedDate not supplied

An assessment of paramedic performance during invasive airway management.

OBJECTIVE: To assess the performance of paramedics, in a newly-initiated prehospital program, during invasive airway management. METHODS: An audit of paramedic call reports for a 12-month period from January to December 1997 was performed. Call reports that documented invasive airway management were retrieved and relevant data were extracted using a preformulated data-entry form. RESULTS: Paramedics attempted tracheal intubation in 453 patients and were successful in 408 (90.1%); 331 of the patients were in cardiopulmonary arrest with vital signs absent (VSA), 101 had medical emergencies, and 21 had trauma-related problems. In the VSA cohort, the tracheas of 96% of the patients were intubated successfully; 80.1% on the first attempt, 10.6% on the second, 4.5% on the third, and 0.9% after more than three attempts. In the medical cohort, the tracheas of 74.3% of the patients were intubated; 60.4% on the first attempt, 11.9% on the second, and 2.9% on the third. In the trauma cohort, 71.4% of the intubations were successful; 66.6% on the first attempt, 26.6% on the second, and 6.6% on the third. There was a difference (p < 0.001) in the incidence of successful intubations comparing the VSA cohort with the medical/trauma cohorts. There was also a difference (p < 0.001) between the success rate for nasal intubations (43 of 68, 63% of patients successfully intubated) and that for oral intubation (365 of 385, 94% of patients). CONCLUSION: This study demonstrated a difference in the paramedics' success rates for tracheal intubation in VSA patients compared with those with preserved airway reflexes and a lower success rate for nasal vs oral tracheal intubation. These differences may be due to inadequate training, technical difficulties experienced in the field, or lack of sufficient exposure to medical/trauma scenarios to gain management experience. Future training to address these issues, both in the initial training phase and in the continuing education program, may be beneficial in improving performance.

Emergency Medical Services↗