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Biomedical subjects

B Abbott

Publications and source records attributed to B Abbott.

At least 91 records · Page 5Linked to original sources
PubMed1996

Evaluation of a supplementary retention program for African-American baccalaureate nursing students.

This study evaluated the Minority Academic Advising Program (MAAP), a supplementary retention program established for African-American students enrolled in a southern state health sciences university's baccalaureate nursing program. The evaluation method merged a quasi-experimental with a time-series design. A group of 114 black students were included in the study. A comparison group consisting of 608 nursing student cohorts who were predominantly white was incorporated for control purposes. Although the students who were MAAP participants had significantly lower SAT scores, reduced Pre-Admission GPAs, and included a contingent of 11 students at high risk of failing, the following enhancements were identified: their retention-to-graduation rate increased 5.3 percentage points to 97.1%, their nursing program GPA increased nearly one-quarter letter grade, their time-persisted-in-program increased 0.7 months, and their nursing board examination pass rate increased 15 percentage points.

Black or African American↗
PubMed1995

Inactivation of adrenal cytochromes P450 by 1-aminobenzotriazole. Divergence of in vivo and in vitro actions.

Recent investigations demonstrated that administration of 1-aminobenzotriazole (ABT) to rats caused adrenal gland enlargement. Studies were done to pursue the mechanism(s) involved. Preliminary experiments revealed that the adrenal enlargement caused by ABT was associated with a decline in plasma corticosterone concentrations, suggesting inhibition of adrenal steroidogenesis. Indeed, a single injection of ABT (25 or 50 mg/kg body weight) to rats caused concentration-dependent declines (60-80%) in adrenal mitochondrial and microsomal cytochrome P450 (P450) concentrations. The decreases in adrenal P450 levels exceeded those in hepatic microsomes. Accompanying the declines in adrenal P450 concentrations were decreases in steroid hydroxylase activities. Mitochondrial 11 beta-hydroxylase and cholesterol side-chain cleavage activities and microsomal 21-hydroxylase activity were diminished markedly (60-90%) by ABT treatment. In contrast, activity of adrenal 3 beta-hydroxysteroid dehydrogenase-isomerase was not affected by ABT, indicating specificity for P450-dependent reactions. Incubation of adrenal microsomes or mitochondria in vitro with ABT plus an NADPH-generating system had no effect on P450 concentrations or on steroid hydroxylase activities. Similar incubations with hepatic microsomes caused declines in P450 levels and in the rates of P450-mediated xenobiotic metabolism. The results demonstrate that ABT is a potent inhibitor of adrenal steroid hydroxylases in vivo, but the in vitro studies indicate that the mechanism of action differs from that on other P450 isozymes. The absence of inhibitor effects in vitro suggests that an extra-adrenal metabolite of ABT is responsible for the in vivo inactivation of steroidogenic enzymes.

Adrenal Glands↗
PubMed1995

Production and characterization of monoclonal antibodies directed against the Ah receptor.

Six hybridomas secreting monoclonal antibodies that are specific for the N-terminal peptide sequence of the murine Ah receptor were isolated. These antibodies bind with high specificity to the Ah receptor on protein blots of Hepa 1c1c7 cytosol. Three IgG1 antibodies (Rpt 1, 2, and 3) were capable of detecting 2 ng of receptor using peroxidase-goat anti-mouse IgG antibody conjugate on a protein blot. Monoclonal antibody Rpt 9 exhibited the greatest ability to immunoprecipitate the nondenatured 9S form of the Ah receptor and to visualize the AhR on liver tissue sections using immunohistochemical techniques. All of the monoclonal antibodies produced were able to bind to the mouse, rat, and human Ah receptor. These monoclonal antibodies should be useful in a wide number of applications in the study of Ah receptor biochemistry.

Amino Acid Sequence↗