Ultrasound-detected thyroid nodule prevalence and radiation dose from fallout.

Settlements near the Semipalatinsk Test Site (SNTS) in northeastern Kazakhstan were exposed to radioactive fallout during 1949-1962. Thyroid disease prevalence among 2994 residents of eight villages was ascertained by ultrasound screening. Malignancy was determined by cytopathology. Individual thyroid doses from external and internal radiation sources were reconstructed from fallout deposition patterns, residential histories and diet, including childhood milk consumption. Point estimates of individual external and internal dose averaged 0.04 Gy (range 0-0.65) and 0.31 Gy (0-9.6), respectively, with a Pearson correlation coefficient of 0.46. Ultrasound-detected thyroid nodule prevalence was 18% and 39% among males and females, respectively. It was significantly and independently associated with both external and internal dose, the main study finding. The estimated relative biological effectiveness of internal compared to external radiation dose was 0.33, with 95% confidence bounds of 0.09-3.11. Prevalence of papillary cancer was 0.9% and was not significantly associated with radiation dose. In terms of excess relative risk per unit dose, our dose-response findings for nodule prevalence are comparable to those from populations exposed to medical X rays and to acute radiation from the Hiroshima and Nagasaki atomic bombings.

Tri- and tetrapeptide analogues of kinins as potential renal vasodilators.

Tri- and tetrapeptide analogues were synthesized and evaluated as renal vasodilators. These peptides were prepared by standard coupling reactions, which also provided good yields with hindered alpha-methyl amino acid derivatives. Preliminary evidence of renal vasodilator activity was determined in anesthetized dogs by measuring the effects on renal blood flow and calculating the accompanying changes in renal vascular resistance. The most potent compounds contained, in their basic structure, the L-prolyl-DL-alpha-methylphenylalanyl-L-arginine and L-prolyl-DL-alpha-methylphenylalanylglycyl-L-proline arrays. Substitution on the N-terminal proline with 4-phenylbutyryl and 4-(4-hydroxyphenyl)butyryl side chains produced enhanced renal vasodilator activity and, in certain cases, selectivity for the renal vasculature.

Studies on the action and interaction of dopamine and prostaglandin A1 in the renal vasculature.

Dopamine (3 mug/kg/min) and prostaglandin A1 (0.2 mug/kg/min) were found to dilate the renal vasculature and increase total kidney blood flow in be anesthetized dog. These effects of dopamine, but not of prostaglandin A1, were completely antagonized by bulbocapnine, a selective dopamine receptor inhibitor, at a dose (3 mg/kg) which did not itself significantly alter cardiovascular hemodynamics. Conversely, indomethacin, an inhibitor of prostaglandin synthetase in the dog at 2 mg/kg, did not reduce the dopamin renal vascular response. These results suggest that dopamine and PGA1 decrease renal vascular resistance in the dog via distinct pharmacological mechanisms.

Analysis of mercurial preservatives in bacterins, vaccines, and antisera by atomic absorption spectrophotometry.

A flameless atomic absorption method was developed for the determination of mercurial preservatives in biologicals. The assay was based on a quantitative determination of the mercury content of these preservatives. This method was used to analyze a variety of samples and yielded reproducible results with satisfactory recoveries. The procedure is presented in a simplified block diagram and described in detail relating its suitability for routine assay of large numbers of samples.