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Biomedical subjects

J Parsons

Publications and source records attributed to J Parsons.

At least 127 records · Page 7Linked to original sources
PubMed1979

Soluble factors from liver and hepatomas which inhibit [3H]thymidine incorporation into DNA of Novikoff hepatoma cells.

The nature of soluble factors from liver and hepatomas which inhibit [3H]thymidine incorporation into DNA was studied in Novikoff hepatoma cells. The decreased activity in hepatoma preparations was due to loss of a high-molecular-weight heat-labile factor. Although this factor cochromatographed with arginase activity on Sephadex G-150, it does not appear to result from this activity as judged by the failure of arginine to prevent the inhibitory effect on [3H]thymidine incorporation. Both liver and hepatomas contained a heat-stable factor with inhibitory activity. Studies with ethanol-soluble material suggested that the action was not solely attributable to the presence of unlabeled thymidine, since the apparent molecular weight was too high and since the factor(s) inhibited [3H]leucine incorporation into protein in addition to inhibiting [3H]thymidine incorporation in DNA.

Animals↗
PubMed1978

Pharmacology and efficacy of netilmicin.

Twenty-six patients, 20 to 77 years of age, were treated with netilmicin, mean dose 2 mg/kg every 8 h intramuscularly or in a 20-min intravenous infusion. The mean serum half-lives in patients with creatinine clearances of >/=90 ml/min and 60 to 90 ml/min were 3.2 and 3.4 h, respectively. In patients with serum creatinines of </=1.4 mg/100 ml and creatinine clearances of >/=60 ml/min, mean serum levels were 9.0 and 1.2 mug/ml, respectively, 5 to 15 min and 7.5 h post-intravenous infusion, and 7.1 and 1.7 mug/ml, respectively, 1 and 8 h post-intramuscular injection. Twenty-five patients had acute pyelonephritis; 7 of the 25 had bacteremia. The infecting bacteria were Escherichia coli (15), Proteus mirabilis (5), Pseudomonas aeruginosa (2), Klebsiella pneumoniae (1), Enterobacter hafniae (1), and both Proteus rettgeri and Proteus morganii (1). All were inhibited by 6.3 mug of netilmicin per ml, except for the P. rettgeri, which required 25 mug/ml for inhibition. Of 23 patients who could be evaluated, 19 were bacteriologically and clinically cured at follow-up. Of the remaining four, one relapsed, two became reinfected, and one was lost to follow-up. Five patients developed nephrotoxicity; two of the five had previous renal insufficiency. Three patients, one with abnormal renal function, developed ototoxicity detected only with audiograms. These studies suggest that netilmicin is effective in serious gram-negative bacillary infections, but is nephrotoxic and ototoxic in humans.

Adult↗
PubMed1977

Arbovirus isolations from, and serological studies on, wild and domestic vertebrates from Kano Plain, Kenya.

Arbovirus infection and presence of haemagglutination-inhibiting antibodies in small mammals, birds and livestock were examined over a period of five years on the Kano Plain in western Kenya. Eleven isolations were made from mammals and birds. The viruses were identified as Arumowot and Germiston while three different agents could not be shown to be related to 188 African arboviruses. Prevalence of antibodies against arboviruses suspected of occurring in the area was generally low.

Animal Population Groups↗
PubMed1975

Effect of corticosteroids on the human monocyte IgG and complement receptors.

A quantitative in vitro assay was employed to directly assess the effect of corticosteroids on the IgG and complement receptor function of human mononuclear phagocytic cells. In this system corticosteroids were solubilized with cholesterol-phospholipid sonicated dispersions before exposure to mononuclear cells. Solubilized corticosteroids at concentrations between 10(-4) and 10(-3) M inhibited both IgG and complement receptor activity in a dose-response fashion. Inhibition was dependent upon the time of interaction of the mononuclear cells with corticosteroids and was half-maximal by 15 min. The inhibitory effect at all concentrations of hydrocortisone was partially overcome by increasing the number of IgG molecules per erythrocyte. Hydrocortisone also inhibited the binding of erythrocytes coated with both IgG and C3, despite the fact that when both were on the erythrocyte surface a synergistic effect on binding to mononuclear cells was observed. At the steroid concentrations employed, the capacity of mononuclear cells to exclude trypan blue and to take up latex particles and neutral red was unaffected. Mineralocorticoids also inhibited receptor activity, but the sex hormones were less effective. These studies demonstrate an effect of steroid hormones on cell membrane receptor function, and they suggest that an inhibition of the recognition system for IgG and C3 in vivo may explain, in part, the effect of corticosteroids in man.

Adrenal Cortex Hormones↗