Radiolucent transient surgical space.
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Biomedical subjects
B D Bass
Publications and source records attributed to B D Bass.
Quantitation of hepatitis B viral markers in a dental school population.
Ample evidence exists that dentists and dental personnel are vulnerable to hepatitis B disease. Epidemiologic studies, which provide a further understanding of the prevalence, infectious nature, and risks of transmission of the hepatitis B virus, are particularly significant in a dental school environment because of the insidious nature of the virus. Screening should be done for anti-HBs because it is the most reliable marker for hepatitis B infection and is generally believed to confer immunity. However, because no experimental data are available concerning the amount of antibody needed for protection, quantitation of anti-HBs levels in human serum or gingival crevicular fluid would be the first step in ultimately correlating antibody titers to the immune process. In this study, we present quantitative data on the relative antibody titers in a dental school population. Our findings may be of importance for monitoring the effectiveness of vaccination, for improving safety guidelines in dental clinics, and for developing new and rapid oral diagnostic screening methods. Recently, a new method using gingival crevicular fluid has been developed; it permits identification of not only antibody, but also of hepatitis B surface and e antigens (L. Andors, and associates, unpublished data).
Adult↗
Reactivity of cyanate with valine-1 (alpha) of hemoglobin. A probe of conformational change and anion binding.
The 3-fold increase in the carbamylation rate of Val-1 (alpha) of hemoglobin upon deoxygenation described earlier is now shown to be a sensitive probe of conformational change. Thus, whereas this residue in methemoglobin A is carbamylated at the same rate as in liganded hemoglobin, upon addition of inositol hexaphosphate its carbamylation rate is enhanced 30% as much as the total change in the rate between the CO and deoxy states. For CO-hemoglobin Kansas in the presence of the organic phosphate, the relative increase in the carbamylation rate of this residue is about 50%. These results indicate that methemoglobin A and hemoglobin Kansas in the presence of inositol hexaphosphate do not assume a conformation identical with deoxyhemoglobin but rather form either a mixture of R and T states or an intermediate conformation in the region around Val-1 (alpha). Studies on the mechanism for the rate enhancement in deoxyhemoglobin suggest that the cyanate anion binds to groups in the vicinity of Val-1 (alpha) prior to proton transfer and carbamylation of this NH2-terminal residue. Thus, specific removal with carboxypeptidase B of Arg-141 (alpha), which is close to Val-1 (alpha) in deoxyhemoglobin, abolishes the enhancement in carbamylation. Chloride, which has the same valency as cyanate, is a better competitive inhibitor of the carbamylation of deoxyhemoglobin (Ki = 50 mM) compared with liganded hemoglobin. Nitrate and iodide are also effective inhibitors of the carbamylation of Val-1 (alpha) of deoxyhemoglobin (Ki = 35 mM); inorganic phosphate, sulfate, and fluoride are poor competitive inhibitors. The change in pKa of Val-1 (alpha) upon deoxygenation may be due to its differential interaction with chloride.
Anions↗