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J Epp

Publications and source records attributed to J Epp.

14 recordsLinked to original sources
PubMed1986

Catalysis of superoxide dismutation by manganese aminopolycarboxylate complexes.

Complexes of manganese, copper, cobalt, and iron with a variety of aminopolycarboxylates at concentrations from 2 X 10(-7) to 3 X 10(-6) M were tested for superoxide dismutase activity with horse ferricytochrome c as the competing reagent for superoxide. In the presence of excess ligand only manganous nitrilotriacetate and manganous ethylenediaminediacetate showed activity with catalytic rate constants of 2.2 X 10(7) and 1.8 X 10(7) M-1 S-1, respectively, at pH 6, 22 +/- 1 degree C, and 10 mM ionic strength. These rate constants decrease considerably at higher pH. Manganous N-hydroxyethylethylenediaminetriacetate is oxidized by superoxide, but does not appear to have catalytic activity. From the experimental conditions under which the two complexes mentioned above exhibit catalysis, and the inactivity of other metal chelates, it is concluded that an open coordination site is essential but not sufficient to catalyze the dismutation reaction.

Binding Sites↗
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Determinants of genital human papillomavirus infection in low-income women in Washington, D.C.

OBJECTIVES: To confirm the risk factors for genital human papillomavirus (HPV) infection. GOAL OF THIS STUDY: To investigate risk factors for HPV detection independent of the correlated risk factors for cervical neoplasia, in a high-risk population. STUDY DESIGN: We investigated 404 cytologically normal women attending medical assistance clinics in the Washington, D.C. area. Risk factor information was obtained and a cervicovaginal lavage was collected and used for HPV detection and typing by a PCR-based technique. RESULTS: The point prevalence of HPV was 33.7%. This contrasts with the 17.7% and 44.3% observed in the companion reports published in this issue of the journal. HPV prevalence decreased with age and increased with greater numbers of sexual partners. Moreover, more recent sexual behavior was a better predictor of current HPV detection than lifetime number of sexual partners. Numbers of pregnancies and current pregnancy were positively associated with HPV prevalence and there was an indication that current oral contraceptive users had a higher prevalence of HPV compared to never users. Smoking was not associated with increased HPV prevalence. CONCLUSION: Findings support the sexual route of transmission of HPV and confirm the association of HPV detection with age, suggesting the host's ability to clear infection or the virus' ability to become latent.

Adolescent↗