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Biomedical subjects

R Coleman

Publications and source records attributed to R Coleman.

At least 307 records · Page 17Linked to original sources
PubMed1980

Selective release of plasma-membrane enzymes from rat hepatocytes by a phosphatidylinositol-specific phospholipase C.

When isolated hepatocytes are incubated with phosphatidylinositol-specific phospholipase C, three cell-surface enzymes show markedly different behaviour. Most of the alkaline phosphatase is released at very low values of phosphatidylinositol hydrolysis, whereas further phosphatidylinositol hydrolysis releases only a maximum of about one-third of the 5'-nucleotidase. Alkaline phosphodiesterase I is not released. If cells containing phosphatidyl[3H]inositol are similarly treated, then the released [3H]inositol is in the form of inositol phosphate: no evidence has been obtained for any covalent association between released [3H]inositol and alkaline phosphatase.

5'-Nucleotidase↗
PubMed1980

The pilot parent program: helping handicapped children through their parents.

The problems of parents whose child is diagnosed or newly identified as mentally retarded or otherwise developmentally delayed are varied and difficult. As many authors have pointed out, the manner in which parents deal with this initial crisis of acceptance can have long term consequences for the parents, the family, and the handicapped child. In the past, neither psychiatry nor the other helping professions did much to provide parents with the elements they need in this profound emotional crisis: continuing emotional support and role modeling, information about the child's handicap, and information about service programs for handicapped persons. The Omaha Nebraska Pilot Parent Program is a volunteer program of parents of handicapped children whose purpose is to provide these supports to parents in need. After seven years such a program appears to provide satisfaction for its members, help to fellow parents, and an important resource to the human services systems in the community.

Attitude↗
PubMed1980

Fine structure of the parathyroid glands in baboons, Papio hamadryas in response to experimental hypercorticoidism.

Female baboons maintained under laboratory conditions were subjected to a series of 10 weekly injections (4 mg/kg body weight) of the synthetic glucocorticoid, triamcinolone hexacetonide. In response to the treatment, serum immunoreactive parathyroid hormone (PTH) levels were raised, though blood calcium levels remained within normal physiological limits. Light and electron-microscopic studies were made on the parathyroid glands at the end of the experimental period. The baboon parathyroid glands were composed of 'light' and 'dark' forms of the chief cells in varying ratios from gland to gland even within a single animal. Glucocorticoid-induced parathyroid hyperactivity as measured by circulating PTH levels was not accompanied by cellular hypertrophy, though there was an increase in the relative number of 'light' cells. At the ultrastructural level, after treatment, many of the 'light' cells were found to contain more free ribosomes, larger profiles of granular endoplasmic reticulum and had better developed mitochondria. Interdigitations between adjacent chief cells were more complex in treated glands. Apart from these features, chief cells of treated glands were basically similar to those of untreated controls. Our study showed that functional parathyroid hyperactivity in baboons is not necessarily accompanied by significant ultrastructural changes in chief cells.

Animals↗
PubMed1980

Steroid-induced ultrastructural changes in the proximal convoluted tubule cells of baboon kidneys with special reference to peroxisomes.

An electron microscopic study was performed on kidneys of immature female baboons, Papio hamadryas, that received a series of 10 consecutive weekly injections of the synthetic glucocorticoid, Triamcinolone hexacetonide (4 mg/kg body wt). In the steroid-treated kidneys the most distinctive change found is a significant increase in the number and a marked change in the form of peroxisomes (microbodies) in proximal convoluted tubule cells. These cells also develop hypertrophic mitochondria and in some instances mitochondrial hyperplasia is present to such a degree as to lead to the formation of "oxyphil-like" mitochondrion-rich cells, containing degenerating nuclei. Many proximal cells also develop large secondary lysosomes packed with fibrous contents. Our results indicate a morphological response in proximal tubule cells caused by the corticosteroid-treatment, though the responses seen may possibly be also due to the development of a secondary hyperparathyroidism.

Animals↗
PubMed1979

Are polyphosphoinositides associated with glycophorin in human erythrocyte membranes?

Glycophorin prepared by a lithium di-iodosalicylate-extraction/phenol-partition method was rich in polyphosphoinositides (phosphatidyl-myo-inositol 4-phosphate and phosphatidyl-myo-inositol 4,5-bisphosphate), but glycophorin extracted by Triton X-100 showed no such enrichment. The enrichment observed in the former preparations appeared not to be caused by pre-existing association between glycophorin and polyphosphoinositides in the human erythrocyte membrane, but to be largely a consequence of the preparative procedures.

Glycophorins↗
PubMed1979

Membranes and bile formation. Composition of several mammalian biles and their membrane-damaging properties.

The total content and profile of bile salts and phospholipids are reported for several mammalian biles. Rabbit and guinea-pig biles are characterized by high proportions of conjugated dihydroxy bile salts with respect to trihydroxy bile salts, but contain relatively little phospholipid. Both rabbit and guinea-pig biles exhibit little evidence of hepatic cell damage, even though they are able to cause membrane damage (as evidenced by lysis of human erythrocytes) at low (2--3 mM) concentrations of bile salts; this lytic behaviour is also a property of their predominant bile salts. Addition of phosphatidylcholine to the bile or bile salt is able to decrease the lytic behaviour. Perhaps the most significant observation is that these biles, and their predominant bile salts, are dramatically less lytic towards sheep erythrocytes, indicating that some factor(s) in membrane composition and structure may partly explain the resistance of membranes of the biliary tract to the presence of high concentrations of potentially membrane-damaging bile salts.

Animals↗
PubMed1978

Erythrocytes within pancreatic B-cells of corticosteroid-treated mice.

An ultrastructural study of the endocrine pancreas of female ICR mice that received 21 daily injections of the synthetic glucocorticoid, Triamcinolone diacetate (8 mg/kg b.wt) revealed some examples of microhaemorrhage within islets of Langerhans, extravasation of erythrocytes, and the presence of erythrocytes within B-cells, where they undergo degradation to form myelin-like configurations.

Animals↗
PubMed1978

Effects of bile salts of human erythrocytes. Plasma membrane vesiculation, phospholipid solubilization and their possible relationships to bile secretion.

Glycocholate removed approximately 25% of the membrane acetylcholinesterase and 10% of the membrane phospholipid from intact human erythrocytes prior to the onset of cell lysis. At low concentrations (up to 6 mM), glycocholate caused human erythrocytes to become echinocytic and to pinch off microvesicles, whereas at higher concentrations glycocholate also specifically released components from the outer leaflet of the plasma membrane in a 'soluble' form (as defined by their presence in a 150 00 X g/60 min supernatant) and caused the cells to become stomatocytic. Whilst the phospholipdi profile of the 'soluble' material differed from that of the whole membrane, the profile of the microvesicle fraction was similar. The microvesicles were depleted in several membrane proteins with respect to phospholipids. These observations are discussed in relation to the possible role of bile salts in the origins of biliary phospholipid and protein.

Acetylcholinesterase↗