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Biomedical subjects

C Livingston

Publications and source records attributed to C Livingston.

11 recordsLinked to original sources
PubMed1987

Isolations of Cache Valley virus in Texas, 1981.

Two strains of the same virus (isolates AR 168 and 7856), were isolated in 1981 from an apparently healthy cow and a sick sheep in TX, U.S.A. These isolates were shown to be members of the Bunyamwera serogroup (family Bunyaviridae, genus Bunyavirus) by complement-fixation tests. Serum dilution-plaque reduction neutralization test results indicated that the isolates are closely related to Cache Valley virus. The virus isolates were characterized by sensitivity to lipid solvent, size (50-100 nm by filtration and 70 nm by electron microscopy), heat (56 degrees C) and pH 3 lability, cytopathic effects or plaques in cultures of Vero, LLC-MK2, embryonic bovine testicle and PS cells, and pathogenicity for suckling and weaned mice by the intracranial but not the intraperitoneal route. Gnotobiotic and conventional sheep and goats were experimentally infected by inoculation with one of the isolates given either intravenously or intraperitoneally. Elevation of body temperature, depression, tremors, muscle spasms, disorientation, feeding anomalies, convulsions, or other signs of central nervous system disturbances were observed.

Animals↗
PubMed1984

NK cell activity and skin test antigen stimulation of NK like CMC in vitro are decreased to different degrees in pregnancy and sarcoidosis.

Peripheral blood mononuclear cells (PBMNC) isolated from normal subjects, pregnant women and patients with sarcoidosis were assayed for natural killer (NK) cell activity on day 0 and for NK like cell-mediated cytolysis (CMC) after 5 days of exposure, in vitro to Candida antigen, purified protein derivative (PPD), and human leucocyte interferon (IFN). Pregnant women and women with sarcoidosis had significantly decreased levels of NK cell activity compared to normal women. Pregnant women had the lowest mean NK cell activity. Cells from women with sarcoidosis and from pregnant women also had lower levels of killing than those from the normal women after in vitro stimulation of NK like CMC with Candida antigen, PPD and IFN. The lowest stimulations of NK like killing occurred in the cells from women with sarcoidosis. Skin test antigen stimulation of NK like CMC in vitro and the DTH response in vivo were strongly correlated for both Candida antigen and PPD in the sarcoidosis patients. There was no correlation between the level of NK cell activity in the PBMNC of sarcoid patients on day 0 and the amount of NK like CMC that was present in cells from those patients after 5 days of culture with Candida antigen, PPD or IFN. A significant correlation was found, however, between Candida antigen stimulation of NK like CMC and IFN stimulation of NK like CMC in both pregnant and sarcoid groups. Reduced NK cell activity on day 0 in a given patient thus did not necessarily indicate that skin test antigen or IFN stimulation of NK like CMC on day 5 would also be depressed. In addition, NK cell activity was often noted to be normal in patients with depressed in vitro stimulation of NK like CMC.

Adult↗
PubMed1984

Cells that mediate NK like cytotoxicity are present in the human delayed type hypersensitivity response.

By inducing delayed type hypersensitivity (DTH) responses under previously formed skin blisters we determined that cells which mediate natural killer (NK) like cytotoxicity are present in the DTH response in man. Similar levels of killing were not present in cells obtained from skin blisters not associated with positive DTH responses. The DTH response associated killer cell was found to be a mononuclear cell that had presumably undergone stimulation since it not only killed NK sensitive K-562 cells, but also NK resistant Daudi target cells.

Adult↗
PubMed1983

Human growth hormone blunts Na2EDTA-induced hypocalcaemia in hyposomatotrophic children.

An infusion of disodium ethylenediamine tetraacetate (Na2EDTA) (0.13 mmol/kg for 2 h) was administered to 10 hyposomatotrophic children prior to and after 6 and 12 months of treatment with human growth hormone (hGH). Total and ionized calcium and immunoreactive parathyroid hormone (iPTH) concentrations were determined. Mean basal total and ionized calcium concentrations did not change during the year of treatment with hGH. The nadir concentrations of total and ionized calcium increased progressively during hGH administration and after 12 months were significantly increased over pre-treatment values (total calcium: pretreatment 1.85 +/- 0.32 (SD) mmol/l, +12 months 2.10 +/- 0.15, P less than 0.01; ionized calcium: pre-treatment 0.55 +/- 0.31 mmol/l, +12 months 0.78 +/- 0.14, P less than 0.05). The mean basal concentration of iPTH increased slightly after 12 months of hGH administration (pre-treatment 72 +/- 18 pg/ml, +12 months 106 +/- 71, P less than 0.05), but Na2EDTA-evoked secretion of iPTH was not significant altered by hGH.

Calcium↗
PubMed1982

Effect of human growth hormone on gastrin secretion in children with hyposomatotropism.

The effect of human growth hormone (hGH) on gastrin secretion was evaluated in 13 hyposomatotropic children and two subjects with bioinactive growth hormone (GH). Serum concentrations of gastrin were quantitated by radioimmunoassay after ingestion of a standard meal and following intravenous infusion of arginine, prior to and after 6 and 12 months of hGH administration. Although the meal provoked a significant increment in gastrin values at each point, hGH did not alter basal concentrations or or meal-evoked secretion of gastrin in these subjects. Arginine had no effect on gastrin levels. Serum immunoreactive insulin concentrations increased in response to eating and arginine, but hGH did not alter the insulin secretory response to either stimulus. It is concluded that hGH did not affect the secretion of gastrin or insulin under the conditions of this study.

Adolescent↗
PubMed1980

Sensitive assay for plasminogen activator of transformed cells.

A sensitive in situ assay for the plasminogen activator of transformed cells is described; it uses the fluorogenic molecule 3',6'-bis(4-guanidinobenzoyloxy)-5-(N'-4-carboxylphenyl)thioureidospiro[isobenz ofuran-1(3H),9'-[9H]xanthen]-3-one. This fluorescein derivative is an excellent active-site titrant of the esterase activity of plasmin. When transformed cells are incubated with purified plasminogen and the resulting plasmin is titrated with the fluorogenic substrate, the amount of plasmin formed is linearly proportional to time and cell number. The assay is sensitive enough to detect quantitatively the plasminogen activator activity of as few as 250 transformed cells. This substrate should be useful in studying quantitatively the correlation between increased levels of plasminogen activator activity and cellular transformation and as a general active site titrant of serine proteases.

Animals↗