Biomedical subjects

G H Hall

Publications and source records attributed to G H Hall.

At least 55 records · Page 3Linked to original sources

PubMed1982

Apparent and measured rates of nitrification in the hypolimnion of a mesotrophic lake.

Three distinct phases were observed in the change of dissolved inorganic nitrogen concentrations in the hypolimnion of Grasmere. The second phase of decreasing ammonia and increasing nitrate concentrations was typical of the nitrification process. Observations on nitrate concentration gradients between surface sediments and the water column and experiments using the nitrification inhibitor N-Serve indicated the in situ activity of chemolithotrophic nitrifying organisms. Nitrification rates were estimated throughout the period of stratification by using the N-Serve and [C]bicarbonate uptake method. Comparison of the field nitrate concentrations with the predicted nitrate concentrations (from estimates of the nitrification rate) indicated that the method underestimated the true rate of nitrification. Possible reasons for this are discussed.

Journal Article↗

PubMed1981

Pharmacological responses to the intracerebral administration of nicotine.

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Animals↗

PubMed1978

Intra-articular methotrexate. Clinical and laboratory study in rheumatoid and psoriatic arthritis.

The effects of intra-articular methotrexate (MTX) were compared with saline in 20 patients with persistent knee effusions due to rheumatoid arthritis (15) and psoriasis (5) in a double-blind pilot study. Clinical improvement was seen in most patients given either MTX or saline and was attributed to joint irrigation during arthroscopy and the placebo effects. MTX had a local anti-inflammatory effect in the psoriatic arthropathies; the percentages of polymorphonuclear cells and pyroninophilic mononuclear cells in synovial fluids fell sharply. Intraarticular hydrocortisone acetate was not anti-inflammatory in 2 psoriatic patients treated subsequently. The anti-inflammatory action of MTX in joints may resemble its effectiveness in controlling the rash of psoriasis.

Adult↗

PubMed1976

Copper toxicity: evidence for the conversion of cupric to cuprous copper in vivo under anaerobic conditions.

We have determined the toxicity to cells of Escherichia coli B of cupric copper applied under aerobic and anaerobic conditions in two ways. The growth of cells in liquid medium incorporating cupric copper shows differential inhibition, comparing aerobic and anaerobic conditions--toxicity being greater under anoxia. The growth of colonies upon agar plates incorporating cupric copper does not show such a differential effect. We conclude that colonies on plates are largely anoxic even when incubated aerobically. EPR spectra of cells obtained at various times after application of cupric copper under anoxic conditions indicate the conversion of a considerable proportion of the Cu(II) to a non-paramagnetic species, probably Cu(I). We demonstrate that Cu(I) is more toxic than Cu(II) to cells when applied under anoxic conditions and conclude that the difference in toxicity of Cu(II) applied to cells under aerobic and anaerobic conditions results from the greater extent of reduction of Cu(II) to Cu(I) under anaerobic conditions.

Aerobiosis↗

PubMed1975