Hand tremor related to smoking habits and the consumption of caffeine in male industrial workers.

Tremor was measured in 49 smokers/snuffers and in 49 non-smokers/non-snuffers in a cross-sectional study. The Kløve-Matthews static steadiness test and TREMOR 7.0 from the CATSYS test system were used to assess the hand tremor. The creatinine (cr) corrected arithmetic mean concentrations of cotinine in urine were 11 microg/g cr (range 0.1-430) in the non-smokers/non-snuffers compared to 1,417 microg/g cr (range 45-3,780) in the smokers/snuffers. The geometric mean urinary caffeine concentrations were 797 microg/g cr (range 0.5-13,330) in the non-smokers/non-snuffers versus 654 microg/g cr (range 0.9-7,470) in the smokers/snuffers. Increased tremor was found in the group of smokers/snuffers compared to the non-smokers/non-snuffers for several parameters on the tremor measurements, e.g. geometric mean tremor intensity of 0.14 m/s(2) (range 0.09-0.40) in the smokers/snuffers versus 0.11 m/s(2) (range 0.07-0.22) in the non-smokers/non-snuffers for the dominant hand were quantified. Also the mean scores on the static steadiness test were inferior in the smokers/snuffers, in particular for the number of touches. The results further indicate that the frequency dispersion is smaller in the smokers/snuffers compared to the non-smokers/non-snuffers. No systematic association was observed between the biomarkers of nicotine and caffeine exposure and the tremor measurements. However, older age appeared to be an important predictor for the magnitude of tremor in the smokers/snuffers, but not in the non-smokers/non-snuffers.

Renal function of chloralkali workers after the cessation of exposure to mercury vapor.

OBJECTIVES: The aims of the study were to assess renal function in chloralkali workers previously exposed to mercury vapor and to assess the impact of selenium status on the biomarkers of kidney function. METHODS: Forty-nine chloralkali workers previously exposed to mercury vapor were compared with 49 age-matched referents in a cross-sectional study. Selected biomarkers of kidney function and biomarkers of selenium status were measured. The index group had been exposed for 13.1 (range 2.8-34.5) years on the average at a mean urinary mercury excretion of 9.3 (range 4.0-25.4) nmol/mmol creatinine a year. The exposure had ceased on an average of 4.8 (range 4.2-10.0) years prior to the examinations. RESULTS: No statistically significant differences were found between the groups for the measured biomarkers of kidney function. The serum selenium concentration and serum glutathione peroxidase activity were associated with the activity of N-acetyl-beta-D-glucosaminidase in urine (U-NAG). The results indicate that having higher glutathione peroxidase activity or a higher serum selenium concentration results in a lower excretion of U-NAG. This effect was the most pronounced in the oldest third of the participants. Apparently the well-known association between U-NAG and age could only be found for the participants with a lower selenium status. CONCLUSIONS: Increased activities of U-NAG during ongoing exposure to mercury vapor appear to be reversible upon cessation of exposure. Selenium status has a substantial impact on U-NAG activity and should be considered in studies of U-NAG excretion.

Chemoselective construction of substituted conjugated dienes using an olefin cross-metathesis protocol.

[Reaction: see text] Various substituted conjugated dienes have been made by olefin cross-metathesis. Using either electronic or steric "protection," one of the olefins of the conjugated diene was deactivated relative to the other for cross-metathesis. The reactions proceed with very high chemoselectivity and, when steric deactivation is used, very high diastereoselectivity.

A neurobehavioral study of chloralkali workers after the cessation of exposure to mercury vapor.

Neurobehavioral functions were examined in 49 male workers who had been previously exposed to mercury vapor. They were compared with 49 age-matched male referents in a cross-sectional study. The average duration of exposure in the index group was 13.1 years at a calculated mean urinary mercury (U-Hg) concentration of 9.3 nmol Hg/mmol creatinine (Cr.)/year. The exposure had ceased on average 4.8 (range 4.2-10.0) years prior to the examinations. Forty-one exposed participants and 40 referents had also been examined approximately 5 years previously, while they were still under ongoing exposure. The neurobehavioral test scores and the number of subjective symptoms were similar in the previously exposed subjects and the referents. No significant differences in the development of the neurobehavioral test scores were observed between those 41 previously exposed subjects who had also been examined while they were still being exposed when compared to the 40 referents. However, the difference in the Digit Symbol Test scores between the two occasions was associated with the concentration of inorganic mercury in whole blood while they were still under exposure. The results suggest that no long-term effects of mercury vapor exposure are found at the exposure level experienced by these workers. The study may indicate that the test performance on the Digit Symbol Test improves after exposure cessation in the subjects with the highest B-Hg concentrations, and that this test may be quite sensitive to the effects of mercury vapor exposure.

Ru(II)-catalyzed cascade reactions in stereocontrolled construction of rigid as-indacene-bridged bis(alpha-amino acid) derivatives.

The key construction in the preparation of as-indacene-bridged bis(alpha-amino acid) derivatives was effected by a Ru(II)-catalyzed RCM cascade reaction of appropriately substituted triynes. The latter were available after stepwise and stereocontrolled alkynylations of (2R)-2,5-dihydro-2-isopropyl-3,6-dimethoxypyrazine as chiral auxiliary. The regio- and stereochemical transformations have been verified by a single-crystal X-ray analysis.