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Biomedical subjects

G Rowe

Publications and source records attributed to G Rowe.

At least 37 records · Page 2Linked to original sources
PubMed1992

The synthesis and function of the Escherichia coli hemolysin and related RTX exotoxins.

The RTX group of exotoxins represents a branch of a family of exoproteins produced by Gram-negative bacteria which share the properties of being secreted by a leader-independent pathway and a tandemly-repeated nine-amino-acid sequence that is responsible for calcium binding. The Escherichia coli hemolysin (HlyA) is the prototype for the RTX exotoxin family which includes the leukotoxins of Pasteurella haemolytica and Actinobacillus actinomycetemcomitans and hemolysins from four Gram-negative genera. A review of the genetics, synthesis, export and target cell reactivity of the E. coli hemolysin is given. An evolutionary tree of the RTX toxin family based on amino acid sequence similarity is presented.

Animals↗
PubMed1990

Computer experiments on the evolution of sex: the haploid case.

We have conducted a set of computer experiments that investigate the conditions under which sexual reproduction can evolve. In these experiments, haploid genomes are treated as integer strings able to undergo mutation and, in the case of sexual strings, recombination, with string sequence (the genotype) determining fitness. Our results indicate that the likelihood of a rare sexual mutant spreading through an otherwise asexual population is small when sexual reproduction entails the classical two-fold cost of males. However, our results indicate that when mutation rates are not excessively high, sexual reproduction constitutes a more efficient fitness optimization algorithm, allowing a sexual population to adapt more quickly to its environment than an asexual population.

Animals↗
PubMed1990

Influence of the solvent on the conformational-dependent properties of random-coil polypeptides. I. The mean-square of the end-to-end distance and of the dipole moment.

Conformational energies for the N-acetyl-N'-methylamides of the 20 natural amino acids were calculated, including the solvent effects, as functions of the angles phi and psi for rotation of the main chain and for six positions chi 1 of the C alpha-C beta bond in the side chain (fixed values for chi 2, chi 3, ...). The computed energies were used to evaluate the mean-square end-to-end distance and mean-square dipole moment of homopolypeptides of the 20 natural amino acids. Ten proteins and three enzymes of current interest were also studied. Slight differences in both properties are found on taking the effects of solvent into consideration. Comparison with other computational and experimental results is made.

Amino Acids↗
PubMed1990

Endoscopic laser cholecystectomy: initial report.

With the recent advent of endoscopic laser cholecystectomy, gallbladder removal has been transformed into a minimally invasive operative procedure. To date, we have performed this technique in 12 patients (nine women and three men, aged 24 to 66 years). Early in our experience, one procedure was converted from the endoscopic technique to a standard open cholecystectomy after the gallbladder was accidentally punctured by the grasping forceps. The remaining 11 cases were completed endoscopically. Eight days postoperatively, one patient underwent reexploration because of bile leakage secondary to a fallen cystic duct (which was thickened from chronic inflammation). Compared with traditional methods, the endoscopic technique resulted in decreased morbidity and discomfort, a shorter hospital stay, minimal scarring, and a faster return to work.

Adult↗
PubMed1990

An erythrocyte glycoprotein of apparent Mr 60,000 expresses the Sc1 and Sc2 antigens.

Immunoblotting with human anti-Sc1 and anti-Sc2 locates the Sc1 and Sc2 antigens to an erythrocyte membrane glycoprotein of apparent Mr 60,000. The antigens are destroyed by pronase, and require intact disulphide bonds for expression. A proportion of the molecules carrying the Sc1 and Sc2 antigens are associated with red cell cytoskeleton preparations. Treatment of intact cells with an Endo F preparation resulted in the loss of the Sc2 antigen but not the Sc1 antigen, suggesting that the Sc2 antigen is dependent on the presence of one or more complex N-glycans for its expression.

Blood Group Antigens↗
PubMed1990

Characterization of monoclonal antibodies against the Escherichia coli hemolysin.

Twelve monoclonal antibodies (MAbs) produced against the Escherichia coli hemolysin (HlyA) encoded by the hemolysin recombinant plasmid pWAM04 were studied. HlyA derivatives from recombinant strains with different plasmids encoding HlyA amino-terminal and carboxy-terminal truncates, HlyA in-frame deletions, and HlyA frameshift mutations were used in immunoblots to localize the antigenic determinants for the anti-HlyA MAbs. The mapping of the MAb epitopes was also facilitated by immunoblotting analysis of HlyA polypeptide fragments derived by cyanogen bromide cleavage. The HlyA epitopes for 11 of the MAbs were mapped to relatively small linear regions of the cytolysin ranging from 28 to 160 amino acids. Five of the MAbs (C10, G8, E2, B7, and D12) neutralized HlyA hemolytic activity to varying degrees. The epitopes for these neutralizing MAbs were found to reside within the following HlyA regions: C10 and G8, amino acids 2 to 160; E2, amino acids 161 to 194; B7, amino acids 518 to 598; and D12, amino acids 626 to 726. Hemolytically active HlyA was dependent on the action of the hlyC gene product. The D12 MAb recognized only HlyA produced by strains with an intact hlyC function. MAb A10 recognized an epitope within the HlyA region from amino acids 728 to 829 where a glycine-rich repeat domain exists; however, this MAb did not neutralize HlyA hemolytic activity. A HlyA domain map showing the anti-HlyA epitope location was constructed.

Animals↗
PubMed1985

Abnormal minor human erythrocyte membrane sialoglycoprotein (beta) in association with the rare blood-group antigen Webb (Wb).

Individuals whose erythrocytes are positive for the rare blood-group antigen Webb (Wb) have an altered form of the minor sialoglycoprotein beta (synonyms glycophorin C and glycoconnectin). This altered sialoglycoprotein beta (beta Wb) has an Mr about 2700 lower than that of normal sialoglycoprotein beta. Treatment of normal sialoglycoprotein beta with endo-beta-N-acetylglucosaminidase F decreased its Mr by about 3600, but similar treatment of sialoglycoprotein beta Wb had no effect. These results suggest the possibility that sialoglycoprotein beta Wb lacks the N-glycosidically linked oligosaccharide found on normal sialoglycoprotein beta.

Blood Group Antigens↗
PubMed1984

Factors explaining the use of health care services by the elderly.

The Anderson model of health services utilization, which relates use of service to predisposing, enabling, and need factors, has not often been applied to an elderly population. In this study, the factors of the Andersen model were used prospectively to predict utilization for a population sample of 1,317 elderly persons. Taken alone, the NEED construct was the most important single predictor of use of physician services, hospitalizations, ambulatory care, and home care. PREDISPOSING factors were better predictors of the use of dental services. Some of the variables studied were not related to utilization in the direction that would have been predicted from previous studies on general populations. Multivariate analyses demonstrated that the three constructs should be applied simultaneously when predicting use of services. These findings can be applied to the specific task of planning services for older people.

Aged↗
PubMed1981

Toward understanding elders' health service utilization.

Providing appropriate health services to the elderly is emerging as one of the major challenges of this decade. Using the theoretical framework developed by Andersen and Aday, this study attempts to improve our understanding of those factors which inhibit or facilitate elders' use of health services. The data come from a 1974 statewide random probability sample of 1,625 noninstitutionalized elders 65 years of age or older living in Massachusetts. Regression analysis is used to study the effects of predisposing, enabling, and need characteristics on the use of five health services: hospitals, physicians, dentists, home care, and ambulatory care. The model explains from 5% to 27% of the variance in health service utilization. Need characteristics, in general, account for most of the explained variance.

Aged↗