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Biomedical subjects

D Brown

Publications and source records attributed to D Brown.

At least 991 records · Page 55Linked to original sources
PubMed1982

Cellular and membrane events involved in the K-induced increase in water permeability of toad skin.

Exposure of the inner surface of toad skin (Bufo marinus) to high [K+] resulted in a marked (up to 7-fold) increase in water permeability (Pf) that was more marked in KC1-Ringer than in K2SO4-Ringer. Although high [K+] did not elicit a maximal increase in Pf, it blunted the hydrosmotic responses to vasopressin, isoproterenol and cAMP. Both "post-cAMP" inhibitors of stimulated water flow, such as diamide and vanadate, and "pre-cAMP" inhibitors, such as methohexital and propranolol, markedly reduced the K response, while exposure to Ca2+-free, KC1-Ringer did not inhibit water flow. Intramembrane particle aggregates, similar to those induced by cAMP-mediated hydrosmotic agents, were seen in the apical membrane of granular cells, just beneath the stratum corneum, in skins exposed to KC1. Available evidence indicates that cAMP might mediate, at least partially, the hydrosmotic effect of high [K+]. In contrast, a role of voltage-dependent Ca2+ channels, described in other cell systems depolarized with K, was not apparent in toad skin.

Animals↗
PubMed1982

Fever and infection in spinal cord injury patients.

Fever, infection, or both occurred at some time during hospitalization in 67% of patients on referral spinal cord injury service. A single cause of fever was generally found, with urinary tract and soft-tissue infections predominating; these responded well to appropriate management. In contrast, spinal cord injury patients on other services seen in consultation by the infectious disease service had far more complicated and advanced disease. Multiple infections were diagnosed in the majority of these patients, with urinary tract and decubitus ulcers predominating. Complicating osteomyelitis was present in more than half of those who had infected decubitus ulcers. In both groups of patients, diagnosis required careful attention to physical and laboratory examination because multiple potentially infected areas could be identified and because usual symptoms were sometimes masked by altered sensation.

Adult↗
PubMed1982

Identifying school children with behavior disorders.

Behavioral screening criteria were developed through the collaborative efforts of multidisciplinary professionals to enable teachers to identify school children with behavior disorders within the school setting. The criteria which were developed provide a step towards a practical means of implementing the legislative mandate of PL 94-142 in a medically and psychologically sound manner. An analysis of the criteria presented in the federal guidelines and working criteria proposed by experts in the field is presented. Increased liaison between professionals of all involved disciplines is encouraged for the identification, evaluation, treatment and placement of behavior disorder children. The background and process of developing the criteria is described.

Affective Symptoms↗
PubMed1982

Biological activity of cloned rat endogenous C-type virus DNA transferred by microinjection.

The biological activity of a molecularly cloned DNA of a rat endogenous C-type leukaemia helper virus, RHHV, was assessed by intranuclear microinjection into normal rat kidney cells (NRK153). Release of rat C-type leukaemia helper viruses by the microinjected cells was examined by superinfection of Kirsten-transformed non-producer cells (K-NRK). Immediate release of helper leukaemia viruses at a very low level was observed only in the NRK153 m3 . 5/cir cells microinjected with the supercoiled form of RHHV DNA in toto, suggesting that the circular form of the virus DNA might have expedited the replication and expression of virus particles. Genome rescue experiments were also performed by co-cultivating the microinjected NRK153 m cells carrying various linear RHHV DNAs, in toto or of subgenomic sizes, with K-NRK cells. The results indicated that both the total and the 5.8 to 6.2 kb DNA fragment proximal to the 5' terminus of the cloned RHHV 8.8 kb DNA were able to rescue successfully a transforming replication-competent pseudotype virus. Subgenomic DNA fragments derived from the centre or the 3' end of the RHHV DNA were ineffective in the genome rescue experiments.

Animals↗
PubMed1982

Localization of the vitamin D-dependent calcium-binding protein in mammalian kidney.

The vitamin D-dependent calcium-binding protein (CaBP) was localized by immunocytochemistry in the rat and human kidney. In both species 80% of the cells lining the distal convoluted tubules contained CaBP. In the connecting segment and the initial collecting tubule of rat kidney, 50% of the cells was positive; in the outer medullary collecting duct only 15% was positive. In the human kidney, collecting ducts in medullary rays contained 50% positive cells, whereas in the rest of the medulla no positive cells were found. The CaBP-positive cells were identified as principal or clear cells by immunoelectron-microscopy, using the protein A-gold technique. Mitochondria-rich dark cells were negative. In principal cells, CaBP immunoreactive sites were found throughout the cytosol and the nuclear euchromatin. No preferential labeling of cellular membranes was found. The data show that CaBP-positive cells are present in tubular regions that are important in regulating the final excretion of calcium. However, the subcellular distribution of CaBP does not suggest a role in the initial transmembrane transport of Ca2+ but rather indicates an involvement in processes regulating intracellular calcium.

Adult↗
PubMed1982

Patterns of filipin-sterol complex distribution in intact erythrocytes and intramembrane particle-aggregated ghost membranes.

When fixed erythrocytes are exposed to the cholesterol probe, filipin, and freeze-fractured, their membrane is labeled with only a limited number of typical, 25 nm diameter filipin-sterol complexes. In addition, the membrane contains many less distinct filipin-induced perturbations that give it an overall rippled appearance. In contrast, red cell ghosts subjected to conditions that result in an aggregation of their intramembrane particles have large particle-free membrane domains which are completely filled with 25 nm filipin-sterol complexes. These results suggest that some constraint exists in the intact erythrocyte membrane which restricts the formation of typical filipin-sterol complexes.

Animals↗
PubMed1982

A clinical and pathological study of inherited glaucoma in New Zealand white rabbits.

The eyes of 7 rabbits with clinical megaloglobus, selected from a large colony, were studied with slit-lamp microscopy, gonioscopy, indirect ophthalmoscopy and tonometry. Selected light and scanning electron microscopy was also performed. There were 11 glaucomatous eyes among the 7 rabbits: gonioscopy demonstrated open iridocorneal angles with absence of pectinate fibres. Incomplete cleavage of the iridocorneal angles in glaucomatous eyes was noted histologically. Because of the similarity of the iridocorneal angles of glaucomatous rabbit eyes with those of human eyes with congenital glaucoma, these rabbits may serve as an experimental model in the understanding and management of certain types of human glaucoma.

Animals↗
PubMed1982

T cell subsets in autoimmune and HBV-induced chronic liver disease, HBs antigen carriers with normal histology and primary biliary cirrhosis: a review of the abnormalities and the effects of treatment.

Review of the limited data currently available on the ratios of helper (OKT4+) to suppressor (OKT8+) T cells in autoimmune liver disease (primary biliary cirrhosis and chronic active lupoid hepatitis) and virally induced liver disease indicates that this OKT4+:OKT8+ ratio is elevated in autoimmune liver disease manifesting hyperglobulinemia. This ratio was decreased in patients with chronic hepatitis B virus infection during the HBe antigen-positive phase of viral replication but reverts to normal in the majority of patients in whom HBV replication has ceased (HBe antibody-positive) and these individuals exhibit normal liver histology. Patients with HBV infection who continue to show elevated ratios after the appearance of HBe antibody also continue to exhibit signs of active hepatitis. The implications of these findings for further research in the management of these disorders is discussed.

Antibodies, Monoclonal↗
PubMed1982

Distribution of intramembrane particles and filipin-sterol complexes in plasma membranes of kidney. I. Corpuscle of Malpighi.

A quantitative study was performed on glomerular cell types from the rat kidney freeze fractured after conventional fixation or following exposure to the sterol-specific antibiotic, filipin. The results reveal a considerable variation on the size and number of intramembrane particles, as well as in the number of filipin-sterol complexes present on plasma membranes of the different cell types present in the glomerulus. These differences in membrane structure probably reflect specialized functions of the individual plasma membranes within the glomerulus. The most striking observation, however, was the low particle content and poor filipin labeling of podocyte foot process bases (which lie against the basal lamina) compared with the rest of the podocyte plasma membrane. The presence of distinct membrane domains in podocytes may be a factor involved in maintaining their specific architecture that is critical for the normal functioning of the kidney filtration barrier.

Animals↗