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Biomedical subjects

D M Brown

Publications and source records attributed to D M Brown.

At least 343 records · Page 19Linked to original sources
PubMed1975

Islet transplantation in diabetic rats receiving corticosteroids.

Pancreatic tissue fragments from neonatal inbred Lewis rats were distributed throughout the peritoneal cavities of isologous diabetic recipients receiving prednisolone on a schedule similar to that used in clinical transplantation beginning 9-44 days before transplantation. Plasma glucose levels in six of seven diabetic rats receiving prednislone returned to normal levels 3 weeks after transplantation. Plasma insulin levels in the animals with successful transplants reached, at 1 week after transplantation, levels measured in normal control rats, but never attained the high insulin levels observed in the normal control animals receiving steroids. As with glucose the insulin levels remained in the normal range, and the animals steadily gained weight. During i.v. glucose tolerance tests (IVGTTs) in the rats with successful transplants at 4, 11-14, and 26-29 weeks after transplantation, the glucose levels were similar to those observed during IVGTTs in the control animals before and during corticosteroid therapy. In contrast, insulin levels during the IVGTTs were lower in the rats with successful transplants than in the control rats with or without steroids; however, insulin release during the IVGTTs was rapid in all animals, both with successful transplants and controls. These observations demonstrate that islet tissue implanted in the peritoneal cavities of diabetic rats receiving immunosuppressive chronic corticosteroid therapy can respond with a rapid and sufficient release of insulin to reverse diabetes as documented by normal glucose levels under stimulated and nonstimulated conditions.

Animals↗
PubMed1975

Studies of the rate of regression of the glomerular lesions in diabetic rats treated with pancreatic islet transplantation.

Diabetes was induced in Lewis rats with streptozotocin. Six to eight months later glomeruli showed mesangial thickening: IgG, IgM and C3 were seen in large quantities in the mesangium by immunofluorescent microscopy. Ten animals then had successful pancreatic transplantation resulting in normal glucose and insulin levels within one to three weeks. Biopsies obtained within the first two weeks following transplantation demonstrated a significant reduction in mesangial thickening and in mesangial staining for IgG, IgM and C3. Three to four weeks after transplantation C3 staining was no longer detected. A gradual reduction in mesangial IgG and IgM localization continued so that by nine weeks following islet transplantation only minimal staining for immunoglobulins was present. Although mesangial thickening was reduced, this abnormality could still be detected in most animals six to nine weeks after transplantation. Three rats showed improvement in glomerular morphology within two weeks despite persistent hyperglycemia. These rats had normal insulin levels at this time. Islet transplantation in inbred diabetic rats effectively returns glucose and insulin levels to normal and results in rapid regression of the light microscopic and immunopathologic glomerular lesions. These studies support the concept of reversible mesangial dysfunction in diabetic rats.

Animals↗
PubMed1975

A preliminary report: biofeedback training for early finger joint mobilization.

Using a newly developed, small, portable EMG biofeedback device for facilitating training, restoration of finger function after surgical repair of tendons was quickly achieved in three patients. Their case reports are discussed and are offered to encourage wider use of biofeedback in the therapy of such patients.

Adult↗
PubMed1975

Serum urate and cholesterol levels in Air Force Academy cadets.

Serum cholesterol and urate levels were measured in 150 young men at 2- to 4-month intervals during their first 18 months at the U.S. Air Force Academy. During the first week of cadet training, mean serum urate levels rose as high as 9.5 mg/100 m/, but decreased after a Sunday break. During this week, urate levels in excess of 8.49 mg/100 m/ were found in 44% of the subjects. Such levels, while definitely exceeding normal limits, were attributed to acute psychosocial stress rather than to an abnormal or pathological process. One month after the completion of basic military training, mean serum urate levels were within normal limits, as were all subsequent mean urate levels. Mean serum cholesterol levels were elevated at three times - during the first week of training, after the first month of the first academic year, and during a week of intense military training in the following spring. Apparently, urate and cholesterol levels were elevated by different aspects of stress. Elevations of uric acid level appeared to reflect stress that excited fear or insecurity. Elevations of cholesterol levels apeared to reflect a stress which the individual perceived as requiring a sustained increase in physical and/or mental performance.

Aerospace Medicine↗
PubMed1975

Human glomerular cells in tissue culture.

Cells from human glomeruli explanted in tissue culture were grown and subcultivated up to 12 to 13 times. Light and electron microscopic studies revealed these cells to be morphologically distinct from fibroblasts. By electron microscopy, an extracellular material resembling basal lamina was seen and prominent intracellular microfilaments were evident. Immunofluorescent microscopy demonstrated reactivity of heterologous antiglomerular basement membrane antibody with aggregates of extracellular material. Absorption experiments using antiglomerular basement membrane antibody showed that the extracellular materiial shared some antigenic components with glomerular basement membrane. Antibody to cultured glomerular cells stained the mesangium and glomerular basement membrane of normal human kidney. This antibody was nephrotoxic in monkeys, induced proteinuria with proliferative glomerulonephritis, and localized to the mesangium and glomerular basement membrane of monkey glomeruli. These findings and the presence of prominent intracellular microfilaments (contractile elements) suggest that the glomerular cells may be of mesangial origin.

Adult↗
PubMed1975

Plasma insulin and glucose levels in diabetic rats prior to and following islet transplantation.

Transplantation of islets of Langerhans into the peritoneal cavity of diabetic rats returns the recipients to a normal metabolic state and provides the capability to respond to a glucose stimulation with a rapid release of insulin. Of the two groups of transplanted diabetic rats studied, each had normal nonfasting glucose levels and normal glucose profiles following intravenous glucose tolerance tests. However, one group had significantly lower insulin levels than normal controls both under nonfasting conditions and 4 minutes following glucose stimulation. The other group demonstrated insulin levels greater than those of the normal controls when drawn under nonfasting conditions and essentially identical to the levels of the normal controls following a glucose load. Each transplanted group responded similarly to normal rats with a rapid release of insulin following glucose administration.

Animals↗
PubMed1974

Renal transplantation in diabetes mellitus in rats.

Immunoglobulins and complement are deposited in the glomerular mesangium of rats with progressive glomerulosclerosis secondary to chemically induced diabetes mellitus. Isotransplantation of a kidney from a rat diabetic for 6 mo into a normal recipient results within 2 mo in the disappearance of IgG, IgM, and beta(1)C from the mesangium and arrest or reversal of the light microscopic glomerular lesions. Kidneys isotransplanted from normal donors into diabetic rats developed mesangial matrix thickening and deposition of IgG, IgM) and beta(1)C in the mesangium. No glomerular changes occur upon transplantation of a normal kidney into a normal rat. These findings indicate that diabetic glomerular changes in the rat are reversible and are secondary to the diabetic state rather than to the inducing agent.

Animals↗