Lead concentration in tap-water and in blood of selected schoolchildren in southern Saxonia.

In a study of associations between lead in blood and in tap-water, 113 blood samples and 140 tap-water samples of schoolchildren aged 9 to 12 years were analysed. Median and maximum values of blood lead were 8.3 and 34.0 micrograms/dl and of lead in tap water 24 and 2600 micrograms/l. Lead pipes were in use in some 50% of the houses. The pH values of the tap-water varied from 5.0 to 8.1. Both factors involved, i.e., lead pipes and acidic tap-water, have to be amended in order to reduce lead exposure in some regions or locations in Germany. This necessity is emphasized by increasing evidence of adverse effects to the central nervous system in children when blood lead levels exceed 10 micrograms/dl.

[The action of phenylmercuriacetate and nitrate in combined application in rats: the thyroid gland, liver enzymes and morphologic findings in the brain and kidney]. / Zur Wirkung von Phenylquecksilberacetat und Nitrat bei kombinierter Verabreichung an Ratten: Schilddrüse, Enzyme der Leber, morphologische Befunde an Gehirn und Nieren.

Rats were exposed to nitrate (NO3-) in drinking water, to phenylmercuryacetate (PMA) by gavage and to NO3- and PMA together during 4 different experiments. PMA impaired kidneys, NO3- thyroid gland, and NO3- and PMA together both organs. In the last case a synergistic effect on the thyroid gland was shown. The lowest effective concentration of NO3- was 40 mg/l. It resulted in histomorphological changes of the thyroid epithelial cells. That low effective dose of NO3- and possible synergistic effects should give a further impulse to take into consideration not only a low iodide intake but also goitrogenic environmental chemicals when evaluating the endemic goitre prevalence.

[Hematologic changes in rats following exposure to dichlorvos]. / Hämatologische Veränderungen an Ratten nach Dichlorvosexposition.

Two different experiments on rats were carried out: an acute intoxication causing clinical symptoms and a subchronical intoxication without any symptoms. After the acute experiment an increase of hemoglobin- and hematocrite values as well as of the mean corpuscular hemoglobin concentration was found. These differences are interpreted to be an increased erythropoiesis after hypoxia. Following the subchronical experiment the parameters mentioned above had decreased. These results linked up to anisocytosis, poikilocytosis and/or polychromasia in 30% of the treated animals and allow to assume a disorder of erythropoiesis. The results require to take in consideration a prophylactic hematological survey of long-term exposed people.

The use of graphic methods in working up multivariate data in toxicology.

There are various graphical methods of analyzing multivariate data. An example from the field of toxicology offers an opportunity to discuss graphical methods as a possibility of framing hypotheses, identifying outliers and classification. An attempt is made to compare these methods.

Reversible and irreversible forms of contractile failure caused by disturbances by general anesthetics in myocardial ATP utilization.

Overdoses of several volatile anesthetics (ether, chloroform, ethyl chloride, halothane, methoxyflurane) as well as of various barbiturates lead to severe contractile failure of the heart. In all cases it was found that at the stage of maximal failure the myocardial stores of ATP and phosphocreatine were increased, indicative of reduced high energy phosphate utilization. Barbiturate-induced failure can be fully reversed by the intravenous injection of CaCl2, isoproterenol, or strophanthin. Simultaneously ATP and phosphocreatine concentrations become normal. In contrast, cardiac failure caused by volatile anesthetics proved to be resistant to this therapy. Electron micrographs showed a normal structure of the transverse tubules in the case of barbiturate failure. On the other hand, after the application of volatile anesthetics, a striking dilatation of the transverse tubular system was observed. The irreversibility of this latter type of contractile failure is probably caused by permanent damage of myocardial ultrastructures involved in excitation-contraction coupling.