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Biomedical subjects

R Mitchell

Publications and source records attributed to R Mitchell.

At least 397 records · Page 22Linked to original sources
PubMed1980

Benzodiazepines modify the agonist responses at a presynaptic GABA receptor.

The stimulus-induced release of [3H]glutamic acid from striatal tissue was actively modulated by a presynaptic GABA receptor. The agonist responses of this GABA receptor were modified stereoselectively by benzodiazepines at low concentrations. The results correlate well with effects seen in [3H]GABA binding experiments and as they demonstrate benzodiazepine-induced changes in GABA receptor properties in a tissue prism preparation, these results suggest that the mechanisms described for extensively disrupted preparations may also apply to whole tissue.

Animals↗
PubMed1980

A novel GABA receptor modulates stimulus-induced glutamate release from cortico-striatal terminals.

The possibility of there being a population of GABA receptors located on cortico-striatal terminals is suggested by [3H]GABA binding studies. Experiments carried out to investigate the stimulus-induced release of glutamate from cortico-striatal terminals revealed an active modulation by a presynaptic GABA receptor. The differential responses of this receptor to a range of GABA agonists suggest that it may represent a novel type of GABA receptor.

Cerebral Cortex↗
PubMed1980

Viral hepatitis markers in blood donors and patients with a history of jaundice.

Selected blood donors, antenatal patients, and hospital patients with a history of jaundice were investigated for evidence of prio exposure to hepatitis A and B viruses. Two markers of hepatitis B-infection were sought--surface antibody (anti-HBs) and core antibody (anti-HBc). The prevalence of both markers was low in jaundice history donors and antenatal patients and was no different from the prevalence in random populations of both groups. In contrast, the prevalence of antibody to hepatitis A-virus (anti-HAV) was very much higher in donors and antenatal patients with a history of jaundice than in random groups of the same age and ethnic origin. Similarly, hospital patients with a history of jaundice showed a very low prevalence of prior hepatitis-B infection and a very high prevalence of prior hepatitis-A infection. The findings suggest that in a country with a low incidence of hepatitis-B carriage a history of jaundice is much more likely to equate with prior hepatitis-A infection than B infection. There is no evidence to support the practice of regarding blood donors or patients with a history of jaundice as a special group with more prior exposure to hepatitis-B virus and thus more likelihood of being long-term carriers of hepatitis-B virus.

Adolescent↗
PubMed1980

Frozen red cells in Rhesus immunization.

The use of frozen washed cells in varying doses in primary Rh immunization is compared to two groups of men with the use of fresh washed cells in a third group. In the first two groups, using frozen cells, doses ranging from 0.5 to 20 ml of whole blood (Group I) are compared with a 200.0 ml dose of red cell concentrate (Group II), while Group III served as a control using a 20 ml dose of fresh washed red cell suspension (9.0 ml concentrated red cell equivalent). The response rate was 93% in Group II compared with only 43% in Group I, suggesting the desirability of using relatively large doses of Rh-positive red cells for primary Rh immunization. The use of frozen washed cells from a special panel for 'booster' injections is also recommended.

Blood Preservation↗
PubMed1980

Significance of tests for HBeAg and anti-HBe in HBsAg positive blood donors.

A sensitive radioimmunoassay method for HBeAg and anti-HBe allowed 98.4% of HBsAg positive blood donors to be classified. HBeAg was more prevalent in blood donors under 30 years of age and anti-HBe was more prevalent in those over 30 years. The mean HBsAg concentration was four times greater in donors with HBeAg than in those with anti-HBe. No significant associations were found with sex, blood groups, or HBsAg subtypes. It is likely that this test system will be extremely useful to blood transfusion centres and hepatitis reference laboratories in the future.

Adolescent↗
PubMed1980

A regional programme to collect plasma for preparation of human immunoglobulin anti-rabies.

We identified over 100 recipients of rabies vaccine (human diploid cell vaccine) and recruited them as plasma donors. Some were plasmapheresed at static centres, others by mobile teams. The operation of these teams is described in detail. No plasma was sent to the Fractionation Centre until the date of vaccination had been checked. Assay results showed that the majority of plasma collected between four and 20 weeks after the second dose of vaccine contained 6 or more IU/ml.

Antibodies, Viral↗
PubMed1980

Experimental pathogenicity of Vibrio parahaemolyticus for the schistosome-bearing snail Biomphalaria glabrata.

The bacterium Vibrio parahaemolyticus was found to be pathogenic for the schistosome intermediate host Biomphalaria glabrata (Say). When administered topically, a nonenteritis-associated strain of the bacterium had an LD50 (median lethal dose) of 6.8 x 10(7) cells per snail. A 5% trichloroacetic acid (TCA) extract from V. parahaemolyticus was found to kill B. glabrata. Sublethal effects of V. parahaemolyticus include shell deterioration and increased heart rate. Both albino aquarium populations and naturally occurring Puerto Rican wild populations of B. glabrata are susceptible to V. parahaemolyticus. This bacterium provides a useful model for the study of pathogens and biological control of schistosome vector snails, since it causes significant mortality and is recognized as a pathogen of other invertebrates.

Animals↗