Biomedical subjects
J McCormick
Publications and source records attributed to J McCormick.
Labelling of hypertensive patients.
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Evidence for an essential sulfhydryl group at the substrate binding site of the A-system transporter of Ehrlich cell plasma membranes.
Plasma membrane suspensions of Ehrlich ascites cells solubilized with cholic acid were used to study the effects of sulfhydryl reagents on Na(+)-dependent amino acid transport. These suspensions were treated with the sulfhydryl binding agents p-chloromercuribenzenesulfonic acid or N-ethylmaleimide prior to reconstitution for the assay of transport activity. The proteoliposomes formed from dissolved membranes treated with p-chloromercuribenzenesulfonic acid showed no Na(+)-dependent alpha-aminoisobutyric acid transport, while N-ethylmaleimide pretreated membranes retained approximately 90% of the original activity. To avoid interference by the N-ethylmaleimide component, further studies were carried out with membranes pretreated with 200 microM N-ethylmaleimide prior to p-chloromercuribenzenesulfonic acid treatment. A concentration of 25 microM p-chloromercuribenzenesulfonic acid inhibited Na(+)-dependent alpha-aminoisobutyric acid transport by 50%. The degree of inhibition was dramatically reduced in the presence of substrates specific for the A transport system. Using an inhibition index to address the efficacy of inhibition in presence and absence of substrates, it could be shown that an index of 1.0 in presence of p-chloromercuribenzenesulfonic acid was reduced to 0.84 with (methylamino)isobutyric acid alone and 0.05 in the presence of 100 mM Na+ and 5 mM (methylamino)isobutyric acid. Na+ alone offered no protection. The results show that sulfhydryl group(s) on the amino acid carrier may be directly involved in substrate binding and that substrate binding sites are functional in the disaggregated membrane state. Furthermore, Na+ directly affects (methylamino)isobutyrate binding, since the degree of protection by the amino acid analogue against p-chloromercuribenzenesulfonic acid inhibition was influenced by the presence of Na+.(ABSTRACT TRUNCATED AT 250 WORDS)
Molecular characterization of HIV-1 isolated from a serum collected in 1976: nucleotide sequence comparison to recent isolates and generation of hybrid HIV.
Human immunodeficiency virus type 1 (Z321 designate, HIV-1Z321), the oldest known HIV, was isolated from a serum sample collected in Zaire in 1976 and was molecularly cloned. Restriction enzyme analysis of unintegrated viral DNA revealed the presence of conserved restriction enzyme cleavage sites in the long terminal repeat sequences. Nucleotide sequence analysis of the 3' end of the viral DNA revealed a pattern similar to other HIV-1 isolates described. However, some of the common restriction sites present in other isolates were absent in HIV-1Z321. The extent of differences between HIV-1Z321 and recent isolates from North America and Zaire was 17.86-18.36% on the nucleotide sequence level and 26.5-33.2% difference in the predicted amino acid sequence in the envelope gene. Differences were also noted in 3'-orf (nef: according to HIV gene nomenclature; see Ref. 42) gene and U3 region of the long terminal repeat sequences of HIV-1Z321 and other isolates. Nucleotide sequence of a HIV-1 isolate, 12 years apart from the present isolates, will provide an important time calibration point for the evolutionary divergence of HIV isolates. Hybrid HIV was also generated by transfecting HIV-1Z321 and HIV-1HTLV-III viral DNAs into cells.
Coronary heart disease is not preventable by population interventions.
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Prevention of disease in the poor world.
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Penalising smokers and drinkers.
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Mixed human immunodeficiency virus (HIV) infection in an individual: demonstration of both HIV type 1 and type 2 proviral sequences by using polymerase chain reaction.
Sera from persons seroreactive to both human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2), by whole-virus (VEIA) enzyme immunoassays (EIAs) for each virus, were selected from a seroprevalence study of 944 persons in Abidjan, Cote d'Ivoire, West Africa, in 1987. These sera were subsequently tested for HIV-1 and HIV-2 antibody specificity by type-specific peptide EIAs (PEIA) and western blot (WB) analysis for both viruses. Peripheral blood monocytes (PBMCs) from representative individuals were cultured in the presence of phytohemagglutinin-stimulated normal donor PBMCs. These cultures were periodically monitored for HIV-1 and HIV-2 proviral sequences by using the selective DNA amplification technique polymerase chain reaction (PCR). As an outgrowth of this study, we report the case of a person dually reactive by various serological techniques in whom proviral sequences from HIV-1 and HIV-2 were detected by PCR. This is the first confirmed case of a mixed HIV-1 and HIV-2 infection in a single individual.
The multifactorial aetiology of coronary heart disease: a dangerous delusion.
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Characterization of Hantaviruses using monoclonal antibodies.
The antigenic relations among nine Hantaviruses from seven different geographic areas were examined in indirect fluorescent antibody test with 12 monoclonal antibodies. Ten monoclonals were prepared against Hantaan virus strain 76-118 and two against Hantavirus B-1, a virus isolated from a tumour in a laboratory rat. Four different serotypes have been differentiated: Hällnäs, Hantaan, Prospect Hill and Rat strain like. Two monoclonal antibodies were able to react with all nine Hantaviruses studied. Rat strain- and Hantaanvirus-specific monoclonal antibodies were documented.
Spontaneous human meal patterns are related to preprandial factors regardless of natural environmental constraints.
There is a positive relationship between the amount people eat in a meal and the length of time since the previous meal (preprandial correlation). This study attempted to ascertain whether this correlation occurs due to environmental constraints on eating. Eight male and 30 female undergraduate students were instructed to list everything they ate and when they ate it. They were asked to make a recording in a diary of their eating and drinking throughout a 9 day period. They were also instructed to indicate whether the meal was spontaneous, in response to hunger or the desire for food, or constrained, determined by external factors. The amount of food energy in each meal was then calculated, and the amount remaining in the stomach at the beginning and end of each meal was estimated with a mathematical model. These data were then correlated with the duration of the intervals preceding and following the meals. The amount eaten in the meals was found to be predictable on the basis of preprandial factors regardless of whether the meal was initiated spontaneously or under environmental restrictions. Significant preprandial correlations were found for both constrained and spontaneous meals. No relationship was found between the amount ingested in the meal and the following interval (postprandial correlation) even when only the meals preceding a spontaneous meal were correlated. There were no significant correlations between the proportion of the meals that were constrained and the magnitude of either the preprandial or postprandial correlations. The findings suggest that humans initiate eating either in response to an externally determined schedule or to a learned schedule when constraints are not present.(ABSTRACT TRUNCATED AT 250 WORDS)
Preventive medicine.
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General practice--a portrait.
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Genomic heterogeneity of AIDS retroviral isolates from North America and Zaire.
In an analysis of the genomic variation of AIDS retroviral isolates from patients living in New York, Alabama, and Zaire, restriction maps were constructed by using seven enzymes, each known to cleave the proviral DNA more than once, in conjunction with Southern blot analysis. The maps of LAV, HTLV-III, and ARV-2 as deduced from their published nucleotide sequences were included in this analysis. The results demonstrated that (i) several "signature" restriction sites were common to all isolates; (ii) with the exception of LAV and HTLV-III, the North American and European isolates were all different from one another and showed no geographical specificity; (iii) the African isolates as a group were more diverse than those from North America and Europe; and (iv) the genomic variability was concentrated within the env gene.
Changes in regional cerebrovascular resistance during partial cerebral ischemia in rats.
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Haemorrhagic fever caused by Crimean Congo haemorrhagic fever virus in Mauritania.
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