[Kinetics of arsenic in human blood after a fish meal]. / Kinetik von Arsen im Blut des Menschen nach einer Fischmahlzeit.

It is well known that fish contains high amounts of arsenic (As) compounds (mean values per wet weight [mg x kg-1] Ballin [1]: 41; Falconer et al. [2]: 14; Staveland et al. [3]: 5.2), which are mainly represented by organic As compounds, especially by arsenobetaine. It is generally assumed that arsenobetaine is rapidly eliminated via the urine and therefore seems to be non-toxic for humans. However, the kinetics of arsenobetaine in human blood are unknown to date. Therefore, the following experiments were performed: 14 women of 24 to 32 years of age voluntarily ingested 179 to 292 g of cooked plaice fillet containing 44 (minimum) to 276 (maximum) mg As x kg-1 dry weight. Hence, the volunteers ingested 2.5 (minimum) to 20 (maximum) mg As per person, equivalent to 0.04 to 0.35 mg As x kg-1 body weight. The element As was measured by atomic absorption spectrometry using the graphite furnace technique in order to detect the total amount of As including that of the stable arsenobetaine. In the blood, the highest As values of 55 +/- 5.8 micrograms x L-1 (median) were found 2 hours after fish ingestion. Subsequently the As concentrations declined reaching 16 +/- 0.69 micrograms x L-1 (median) 48 hours after fish ingestion. In respect of the As values in blood recorded between 2 and 10 hours after fish ingestion, rapid elimination could be observed leading to a half-life of 7.1 hours (first value) recorded by linear regression analysis. With regard to the As values in blood between 10 and 48 hours after fish ingestion, a lower elimination rate was estimated with a longer half-life of 63 hours (second value). The reason for this delayed elimination of As is not known. The results indicate that As mainly absorbed as arsenonetaine due to ingestion of fish is not eliminated as fast as had been expected on the basis of published data. As long as it is not known what happens to arsenobetaine remaining for longer periods in the blood with a half-life of 63 hours, caution is advised regarding the general opinion that arsenobetaine is rapidly eliminated and non-toxic for human consumption.

The selective activation of the cardiac sarcolemmal sodium-calcium exchanger by plasmalogenic phosphatidic acid produced by phospholipase D.

Since plasmalogens are the predominant phospholipid of cardiac sarcolemma, the activation of the sodium-calcium exchanger by either plasmenylethanolamine or plasmalogenic phosphatidic acid generated by phospholipase D was explored. Sodium-calcium exchange activity was 7-fold greater in proteoliposomes comprised of plasmenylethanolamine compared to proteoliposomes comprised of only plasmenylcholine. Phospholipase D treatment of proteoliposomes resulted in 1 mol % conversion of plasmenylcholine or phosphatidylcholine to their respective phosphatidic acid molecular species with a concomitant 8-fold or 2-fold activation of sodium-calcium exchange activity, respectfully. Thus, phospholipase D-mediated hydrolysis of plasmalogens to phosphatidic acid may be an important mechanism for the regulation of the sodium-calcium exchanger.

Expectations of preschool children to protect themselves from cigarette smoke: results of a smoking prevention program for preschool children.

Because preschoolers and first graders show signs of readiness to try smoking and because they are already learning about smoking through their environment, smoking prevention at the preschool level is appropriate. The large numbers of children seen in primary care practices and day care facilities are indicative of the numbers that could be exposed to smoking prevention instruction through these settings. This study assessed the future expectations of children to protect themselves from sidestream smoke after participating in a preschool smoking prevention program offered in four primary care settings. Through this program, children and their parents read stories and complete activities concerning the human body and the health risks of smoking. Using a randomized posttest-only case control design, the authors found that children who were exposed to the curriculum were more than twice as likely as others to report the intention to act to protect themselves from adult sidestream smoke.