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Biomedical subjects

B L Williams

Publications and source records attributed to B L Williams.

68 records · Page 4Linked to original sources
PubMed1979

Use of an immunoperoxidase method for identification of Bacteroides fragilis.

An indirect immunoperoxidase (IP) slide test was evaluated for the laboratory identification of Bacteroides fragilis. Antigen-antibody complexes were detected with goat anti-rabbit immunoglobulin G-peroxidase conjugate with 3-amino-9-ethyl-carbazole as the peroxidase substrate. Ninety-one percent of 44 B. fragilis strains tested were IP positive (3+ to 4+ reactions) with greater than or equal to 1:160 dilutions of rabbit antiserum produced against whole cells of B. fragilis ATCC 23745. The antiserum was species specific. No cross-reactions were observed with 35 Bacteroides strains of other species or with a variety of facultative or aerobic gram-negative bacilli. Four B. fragilis strains were IP negative. One of these (VPI 2393) was the deoxyribonucleic acid (DNA) homology group II reference strain. The other three were clinical isolates. IP-negative and representative IP-positive strains were tested for DNA homology with the type strains for DNA homology groups I and II (VPI 2553 and VPI 2393). Two of the three clinical isolates were classified as DNA homology group II, and the remaining strain was classified as a group I. Capsular material known to be unique to B. fragilis was common to both DNA homology groups as indicated by reactions with purified anticapsular antiserum. The IP technique provides a suitable alternative to fluorescent microscopy for the rapid immunological identification of B. fragilis.

Antigens, Bacterial↗
PubMed1979

Synonymy of strains of Center for Disease Control group DF-1 with species of Capnocytophaga.

Of eight strains of Center for Disease Control group DF-1 examined, seven had 62 to 87% deoxyribonucleic acid homology with the neotype strain of Capnocytophaga ochracea and one had 72% deoxyribonucleic acid homology with the type strain of C. gingivalis. Deoxyribonucleic acid homology of four strains of Bacteroides ochraceus with the neotype strain of C. ochrecea was 76 to 86%.

Bacteroides↗
PubMedDate not supplied

Inter- and intra-ethnic variation in water intake, contact, and source estimates among Tucson residents: Implications for exposure analysis.

Water-related exposures among Hispanics, particularly among Mexican Americans, are relatively unknown. Exposure and risk assessment is further complicated by the absence of good time-activity data (e.g., water intake) among this population. This study attempts to provide some insight concerning water-related exposure parameters among Hispanics. Determining the extent to which non-Hispanic whites and Hispanics living in the Tucson metropolitan area differ with respect to direct water intake and source patterns is the primary purpose of this investigation. Using random digit dialing, researchers conducted a cross-sectional telephone population survey of 1183 Tucson residents. Significant ethnic variation was observed in water intake patterns among this sample, particularly in terms of source. Hispanics reported much higher rates of bottled water consumption than did non-Hispanic whites. Ethnic variation in exposure parameters such as that observed in this study increases the potential for measurement error in exposure analysis. Erroneous assumptions that exposure estimates (i.e., water intake source) are generalizable across various ethnic groups may lead to both overestimation and underestimation of contaminant exposure.

Adult↗