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Biomedical subjects

A Perry

Publications and source records attributed to A Perry.

At least 163 records · Page 9Linked to original sources

Enhancement of mannose-mediated stimulation of human granulocytes by type 1 fimbriae aggregated with antibodies on Escherichia coli surfaces.

In the present study, we assayed protein iodination in human granulocytes after interaction of the cells with mannose-specific (MS) type 1 fimbriated (MS+) and nonfimbriated (MS-) phenotypes of Escherichia coli pretreated with various amounts of anti-E. coli and antifimbrial antibodies. The MS+ phenotype stimulated protein iodination in granulocytes and possessed potent MS activity as measured by yeast aggregometry. In contrast, the MS- phenotype lacked all these activities. MS+ pretreated with moderate concentrations of antibodies, however, showed up to a 15-fold increase in granulocyte stimulation as compared to granulocyte stimulation induced by the non-antibody-treated MS+ phenotype or by the antibody-treated MS- phenotype. This marked antibody-mediated increase in stimulation of granulocytes was (i) dependent on the antibody concentrations, (ii) markedly reduced by methyl-alpha-D-mannoside, (iii) caused by immunoglobulin G as well as by F(ab')2, (iv) caused only by antifimbrial antibodies, (v) associated with cross-linked fimbriae seen as "bundles" under an electron microscope, and (vi) mimicked by treating MS+ bacteria with a certain range of glutaraldehyde. The data taken together support the hypothesis that, although cross-linking of fimbriae reduced the density of functional MS fimbriae over the surface of antibody-treated bacteria and consequently reduced the ability of these organisms to agglutinate yeast cells, the resulting bundles of MS fimbriae were far more effective at stimulating granulocytes because, bound together, they were better equipped to aggregate the mannose-containing receptors on the granulocyte surface.

Antibodies, Bacterial↗

Paroxysmal language disturbance in an epileptic treated with clobazam.

An 18-year-old male student had a 3-month history of partial seizures with cognitive symptomatology, with occasional secondary generalization. After 3 weeks of treatment with clobazam 20 mg a day, the patient developed, in association with his seizures, a neologistic jargon dysphasia but with loss of inflection, volume, and rhythm of speech, presumably as a result of the effect of the clobazam.

Adolescent↗

Aging attitudes to home accidents.

Twenty-six people over the age of 65 living in Exeter and Seaton (Devon) were interviewed to determine their attitudes to prevention of home accidents. All had positive attitudes to accepting advice. The majority preferred a familiar person to give the advice.

Accidents, Home↗

Estimation of branched-chain alpha-keto acids in blood by gas chromatography.

Plasma or whole blood is treated with o-phenylenediamine dihydrochloride in phosphoric acid under conditions found spectrophotometrically to give maximum yields of the quinoxalinols. The quinoxalinols are extracted and, after removing phosphoric acid, etc., silylated with bis-trimethylsilyltrifluoracetamide in acetonitrile. Other solvents caused instability of the trimethylsilyl(TMS)-quinoxalinols. Gas chromatography on a packed column of trifluoropropyl silicone gave good separation of the TMS-quinoxalinols from one another and from other substances derived from blood. Some representative values for normal arterial and venous human and canine plasma are reported.

Animals↗

A modification of the Blom-Singer valve for restoration of voice after laryngectomy.

The authors have been involved in developing a modification of the Blom-Singer valved prosthesis for restoration of voice after laryngectomy. This is a case report on the first patient who underwent this procedure in Britain. It was found essential that a different design of valved prosthesis be invented and this is described. Aspects for consideration when selecting a potential candidate for this procedure are outlined, and guidelines given for choosing suitable patients.

Aged↗

Genetic variance of blood pressure levels in infant twins.

A cohort of 166 twin pairs (67 monozygotic and 99 dizygotic) born at the Jackson Memorial Hospital/University of Miami Medical Center between July 1, 1976 and December 31, 1980, was followed from birth to one year of age in order to estimate the genetic variance of blood pressure during the first year of life. The sex-adjusted summary estimate of heritability for systolic blood pressure during all of infancy was 0.22 (p less than 0.001), but statistically significant genetic variance was not found for diastolic blood pressure. When using blood pressures from six to 12 months of age, adjusted for infant sex, heritability was estimated as 0.33 (p less than 0.001) for systolic blood pressure and 0.24 (p = 0.04) for diastolic blood pressure; adjustment for body weight reduced these estimates to 0.27 (p less than 0.001) and 0.17 (p = 0.13), respectively.

Blood Pressure↗

Adherence of Acinetobacter calcoaceticus RAG-1 to human epithelial cells and to hexadecane.

The ability of Acinetobacter calcoaceticus RAG-1 to adhere to human epithelial cells was investigated and compared with its ability to adhere to a test hydrocarbon (hexadecane). RAG-1, a microorganism originally isolated for growth on hydrocarbon, adhered to epithelial cells when grown under conditions which promote its adherence to hexadecane; similarly, RAG-1 cells adhered poorly to epithelial cells when grown under conditions which cause the cells to possess low affinity towards hexadecane. A mutant derived from RAG-1, MR-481, deficient in its ability to adhere to hydrocarbon, was similarly unable to adhere to epithelial cells. RAG-1 adherence to epithelial cells was not blocked by a number of sugars tested. Streptococcus pyogenes, whose adherence to epithelial cells has been previously attributed to hydrophobic interactions, was also able to adhere to hexadecane. Results suggest that hydrophobic interactions mediate adherence of the strains studied to both epithelial cells and hydrocarbon.

Acinetobacter↗

Fracture healing in the rat tibia: open medullary pin versus closed medullary pin insertion.

Fracture healing was compared in open medullary pin fixation and closed medullary pin fixation of the rat tibia to determine if the closed method promotes healing faster than the open method. Severe and mild closed tibial fractures were fixed immediately by open and closed medullary pin fixation methods, and fracture healing was tested mechanically. Diaphyseal fractures treated immediately by closed medullary pin fixation healed faster than those treated by the open pinning; the difference was statistically significant in mild fractures, but not in severe fractures.

Animals↗

Simultaneous radioimmunoassay for specific antibodies to members of the human herpesvirus group.

A method of described for the simultaneous radioimmunoassay (RIA) for antibody to members of the human herpesvirus group. The RIA is compared with some of the conventional serologic techniques used to quantitate antibody to these viruses (Epstein-Barr virus, cytomegalovirus, herpesvirus type 1 and varicella-zoster virus). Color-coded beads, each coated with the antigens of a different herpesvirus, were similtaneously placed in a well which contained a human serum to be assayed for antibody to each of these 4 viruses. The results of this test were compared with the results obtained when the serum was assayed for antibody to the 4 viruses in 4 separate tests. We conclude that the antigen-antibody reactions do not significantly interfere with each other when a serum is assayed for antibody to the 4 viruses simultaneously. A comparison of the RIA with conventional serologic techniques shows excellent correlation in the antibody titers obtained. Features of the solid-phase RIA allow significant savings of time, reagents and space, and thus make it feasible for the small laboratory to screen large numbers of sera for antibody to a variety of antigens.

Antibodies, Viral↗

Emulsifier of Arthrobacter RAG-1: specificity of hydrocarbon substrate.

The purified extracellular emulsifying factor produced by Arthrobacter RAG-1 (EF-RAG) emulsified light petroleum oil, diesel oil, and a variety of crude oils and gas oils. Although kerosine and gasoline were emulsified poorly by EF-RAG, they were converted into good substrates for emulsification by addition of aromatic compounds, such as 2-methylnaphthalene. Neither aromatic nor aliphatic fractions of crude oil were emulsified by EF-RAG; however, mixtures containing both fractions were emulsified. Pure aliphatic or aromatic hydrocarbons were emulsified poorly by EF-RAG. Binary mixtures containing an aliphatic and an aromatic hydrocarbon, however, were excellent substrates for EF-RAG-induced emulsification. Of a variety of alkylcyclohexane and alkylbenzene derivatives tested, only hexyl- or heptylbenzene and octyl- or decylcyclohexane were effectively emulsified by EF-RAG. These data indicate that for EF-RAG to induce emulsification of hydrocarbons in water, the hydrocarbon substrate must contain both aliphatic and cyclic components. With binary mixtures of methylnaphthalene and hexadecane, maximum emulsion was obtained with 25% hexadecane.

Arthrobacter↗

In vitro production of Rauscher murine leukemia virus: influence of culture age on biological properties.

Large-scale production and concentration procedures have been standardized to study the biological properties of Rauscher leukemia virus produced from the high-passaged JLS-V9-H mouse bone marrow cell line. Virus produced early (days 4 to 6) in the harvest and refeed cycle contained higher levels of ribonucleic acid-directed deoxyribonucleic acid polymerase activity and was more infectious than Rauscher leukemia virus produced later (days 7 to 10) in the growth period. The peak of virus production as detected by physical assays (virus particle count, protein, and p30 antigen) was highest at day 6, whereas the optimum biological and ribonucleic acid-directed deoxyribonucleic acid polymerase activity occurred 24 h earlier. When product characterization values of each concentrate were adjusted to a specific activity (i.e., per milligram of protein) basis, virus particle counts averaged 4 x 10(11) through days 5 to 9, and the peak infectivity occurred at day 4, whereas ribonucleic acid-directed deoxyribonucleic acid polymerase activity was highest at day 4 (endogenous) and 5 (exogenous). Sodium dodecyl sulfate-polyacrylamide gel analysis revealed only slight differences in the polypeptide pattern of Rauscher leukemia virus harvested from cultures of varying age, although Rauscher leukemia virus produced between days 3 and 5 contained more glycoprotein than either earlier or later harvests.

Animals↗

Method for reproducible large-volume production and purification of Rauscher murine leukemia virus.

Rauscher murine leukemia virus was produced in roller-bottle cultures of chronically infected JLS-V9 cells. Virus from this culture fluid was concentrated and purified by two semi-isopycnic bandings in sucrose gradients. Virus material obtained from young, nonconfluent cultures (early-harvest virus) yielded products characteristically containing endogenous ribonucleic acid-dependent deoxyribonucleic acid polymerase with high specific activity (400 to 1,000 pmol of [3H]thymidine 5'-triphosphate incorporated per milligram of protein per hour). Fluids obtained from older confluent cultures (late-harvest virus) yielded products with endogenous ribonucleic acid-dependent deoxyribonucleic acid polymerase with little or no specific activity (200 pmol or less of [3H]thymidine 5'-triphosphate incorporated per milligram of protein per hour), but with higher virus particle counts and greater amounts of protein and gs antigen than the early-harvest products.

Cell Line↗

Molecular nature of R-factor deoxyribonucleic acid isolated from Salmonella typhimurium minicells.

In earlier reports it was shown that a variety of extrachromosomal elements harbored in the Escherichia coli minicell producer segregate into the minicells. We show in this report that the fi(+) R factor R-100-1 (derepressed derivative of R-100) similarly segregates into minicells produced by a Salmonella typhimurium strain. Four distinct classes of covalently closed circular deoxyribonucleic acid molecules are found in minicells derived from the R(+)Salmonella minicell producer. The sum of the average molecular weights or contour lengths of the circular molecules in two of the classes is equal to the average molecular weight or contour length of those in a third class. The data suggest that R-100-1 dissociates into resistance determinants (i.e., genes that specify the molecules that confer resistance) and the resistance transfer factor (i.e., genes responsible for the transferability of the R factor to a recipient). In contrast, only one molecular species is found in minicells derived from the R(+) (R-100-1) Escherichia coli minicell producer. The fourth size class consists of small covalently closed circles (minicircles), which were originally found in the R(-)Salmonella minicell producer and are shown in this report to be enhanced in number in R(+)Salmonella minicells.

Bromides↗