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Biomedical subjects

T Thomas

Publications and source records attributed to T Thomas.

At least 343 records · Page 19Linked to original sources
PubMed1977

Management of hyperstimulation syndrome.

A case of hyperstimulation syndrome secondary to Pergonal therapy is presented. Successful management was based principally on severe sodium and fluid restriction without the use of volume expanders. The rationale for this therapeutic approach is presented and discussed. Although this iatrogenic disease should be virtually eliminated with the monitoring of daily urinary estrogens, severe hyperstimulation may still occur as a result of laboratory error.

Adult↗
PubMed1975

Biphasic effect of the alpha-adrenolytic phentolamine on hormone-stimulated formation of cyclic adenosine-3',5'-monophosphate in isolated fat cells of rats.

Isolated fat cells from rat epididymal adipose tissue were incubated with various lipolytic hormones in the absence and presence of the alpha-adrenergic blocking agent phentolamine. Lipolysis, stimulated by noradrenaline, isoproterenol, or ACTH, was inhibited dose-dependently by phentolamine. At concentrations of phentolamine where lipolysis was already inhibited, phentolamine had a biphasic effect on hormone-stimulated formation of cAMP. Low concentrations of phentolamine enhanced cAMP formation, while high concentrations inhibited cAMP. The additional increase of cAMP formation by phentolamine was only seen with maximally effective concentrations of noradrenaline, isoproterenol, and ACTH. Half-maximally effective concentrations were invariably inhibited by phentolamine. The activity of noradrenaline-stimulated adenylate cyclase of fat-cell plasma membranes was inhibited by phentolamine, whereas cAMP phosphodiesterase activity was unaffected.

Adipose Tissue↗
PubMed1972

Disordered blood coagulation in burned children receiving high molecular weight dextran.

Coagulation studies were performed on nine children with burns. Four of these children received treatment which included intravenous dextran; all four showed abnormalities of coagulation and two of them developed a bleeding state. No abnormalities of haemostasis were detected in the remaining five children who had comparable degrees of burns but whose treatment did not include intravenous dextran.

Blood Coagulation↗
PubMedDate not supplied

Plasma protein synthesis and secretion in the visceral yolk sac of the fetal rat: gene expression, protein synthesis and secretion.

This report compares the relative levels of messenger RNA species coding for plasma proteins in rat visceral yolk sac and fetal liver from 12.5 days to 21.5 days gestation. Transthyretin, retinol-binding protein, transferrin and alpha 1-fetoprotein mRNAs were detected in both tissues, although relative levels were much higher in the yolk sac compared to fetal liver, in early gestation. Messenger RNA coding for the positive acute phase proteins thiostatin, fibrinogen, alpha 2-macroglobulin and alpha 1-antitrypsin were detected at a low but significant level in yolk sac, while the levels in fetal liver steadily increased from 16.5 days gestation and, with the exception of alpha 1-antitrypsin, reached levels higher than those found in adult liver just prior to birth. Albumin, inter-alpha 1-trypsin inhibitor, alpha 1-acid glycoprotein, haptoglobin, vitamin D-binding protein and ceruloplasmin messenger RNA levels were either very low or undetectable in yolk sac and fetal liver. Secretion of proteins by yolk sac endoderm occurred largely across the basolateral surface, i.e. towards the fetal compartment. These data support the hypothesis that one function of the yolk sac in the rat is the synthesis and secretion of a select group of plasma proteins to maintain homeostasis in the fetal compartment in the period before the fetal liver has matured sufficiently to carry out this function.

Albumins↗
PubMedDate not supplied

Differential expression of laminin, nidogen and collagen IV genes in the midgestation mouse placenta.

The distribution of laminin A, B1, B2, nidogen and collagen alpha 1(IV) mRNA was studied in the 12.5-day mouse placenta and uterus. This was compared to the pattern of laminin, nidogen and collagen IV immunoreactivity in the placenta at this time. High levels of B2 mRNA were distributed throughout the decidual layer, compared to lower levels of laminin B1, nidogen and collagen IV. In contrast, laminin B1 and nidogen mRNA were found at very high levels in the trophoblast giant cells and cytotrophoblast. Laminin B2 was much lower in trophoblast cells than in the decidua. Nidogen mRNA levels were low in the decidual cells, but high in endothelial cells lining the placental blood spaces in the decidual layer. Immunofluorescence staining of the placenta showed colocalization of laminin, nidogen and collagen IV in fetal and maternal layers of the placenta. In the antimesometrial area where the uterine epithelium was reforming laminin B1 and B2 mRNA were uniformly distributed between the epithelium and stroma, whereas nidogen and collagen alpha 1(IV) mRNA were only produced by the stromal cells. In all cell types, apart from parietal endoderm cells forming Reichert's membrane, laminin A chain mRNA was very low or absent. These results demonstrate that laminin and nidogen genes are not coordinately expressed in the midgestation mouse placenta. Comparison of the distribution of these mRNAs with collagen alpha 1(IV) mRNA suggests that different regions of the placenta produce specialized extracellular matrices which may contain different ratios of these polypeptides.

Animals↗
PubMedDate not supplied

Distribution of alpha 2-macroglobulin and alpha 1-acid glycoprotein mRNA shows regional specialization in rat decidua.

In situ hybridization histochemistry was used to detect mRNA coding for the plasma proteins alpha 1-acid glycoprotein and alpha 2-macroglobulin in the rat decidua during the period when the chorioallantoic placenta is established. It was found that alpha 1-acid glycoprotein mRNA was localized to a subpopulation of decidual cells predominantly found in the decidua capsularis but extending into the decidua basalis at later times. The highest levels of alpha 2-macroglobulin mRNA were found in the decidua basalis where there was some overlap with regions containing alpha 1-acid glycoprotein mRNA. No alpha 2-macroglobulin mRNA could be found in the inner part of the decidua capsularis where the highest levels of alpha 1-acid glycoprotein mRNA were found. However, a thin outer layer of compressed stromal cells, adjacent to the myometrium expressed the alpha 2-macroglobulin gene which surrounded the cells containing alpha 1-acid glycoprotein mRNA. This distribution of alpha 2-macroglobulin mRNA is consistent with the hypothesis that the protein is produced locally to prevent non-specific proteolysis which may otherwise result from catabolic processes involved in tissue remodelling. The function of alpha 1-acid glycoprotein is unknown but this protein is also likely to be involved in the maintenance of homeostasis during the period when contact between maternal and fetal systems is being established within the chorioallantoic placenta.

Animals↗
PubMedDate not supplied

Monoamine oxidase-B inhibitors in the treatment of Alzheimer's disease.

The monoamine oxidase-B (MAO-B) inhibitor L-deprenyl (Selegiline) is effective in treating Parkinson's disease and possibly Alzheimer's disease, with a concomitant extension of life span. It has been suggested that the therapeutic efficacy of L-deprenyl may involve actions other than the inhibition of the enzyme MAO-B. This article reviews some novel actions of L-deprenyl and suggests that stimulation of nitric oxide (NO) production could be central to the action of the drug. L-Deprenyl induced rapid increases in NO production in brain tissue and cerebral blood vessels. In vitro or in vivo application of L-deprenyl produced vasodilatation. The drug also protected the vascular endothelium from the toxic effects of amyloid-beta peptide. Because NO modulates activities including cerebral blood flow and memory, and reduced NO production has been observed in AD brain, stimulation of NO production by L-deprenyl could contribute to the enhancement of cognitive function in AD. MAO-B inhibitors are unique in that they exert protective effects on both vascular and neuronal tissue and thus warrant further consideration in the treatment of vascular and neurodegenerative diseases associated with aging.

Alzheimer Disease↗