Zentralblatt fur Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene. Erste Abteilung Originale. Reihe B: Hygiene, praventive Medizin最新文献

The results of the present investigation point to an up to now little recognized possibility of bacterial transmission by dental turbines, namely, the intake of spray water by reverse suction from the turbine hand piece into the cooling water system on turning off the unit. Reverse suction is provided in most modern dental turbine units to prevent after-drip and the cooling of the pre-warmed spray. As a consequence, microorganisms of the oral flora and possibly disease-producing bacteria may be carried into the cooling water system and thus be transmitted to the next patient when using the same turbine. In carefully planned experiments employing E. coli as test organisms it could be shown both in simulated manipulation in the oral cavity as well as in in vitro experiments that transmission of bacteria is possible in up to 10 ml of spray water ejected (equivalent to 10 spray water fractions of 1 ml each). In older model turbines without spray water reverse suction, bacteria were absent after ejection of no more than 6 ml of cooling water (in fractions of 1 ml each). In order to avoid transmission of bacteria in spray water of dental turbines it appears necessary to subject the turbine hand piece or the turbine head, resp., to rigorous disinfection and to allow delivery of at least 20 ml of spray water - corresponding to about 20 second's operation - before reusing the unit.

In the last five years investigations of environmental samples by high resolution-low voltage mass spectrometry succeeded in better separations of aromatic compounds than with any other method before. In light fuel oil, in dusts from a highway and from towns and in the emissions of an oiloven for households namely at least 200 and up to 500 cyclic and polycyclic aromatic types of compounds of different molecular formulas were detected. From these many types of compounds contained oxygen and some sulfur. In the present study the question is discussed which known carcinogens can be among this abundance of types of compounds. For this purpose at first the carcinogenic polycyclic aromatics with formulas CnH2n+Z, CnH2n+ZO, CnH2n+ZO2 and CnH2n+ZS and the metabolites containing oxygen are listed according to the characteristic of the mass spectrometric method. Pure hydrocarbons there are 62 and sulfur containing 2 carcinogenic compounds with all together 29 different molecular formulas. In the following some comments are made on the methods of analyzing polycyclics. Judged by molecular formulas all samples mentioned can include the CnH2+Z- and the Cn H2n+ZS-carcinogens almost completely. Beyond that in the emissions of the oiloven the occurrence of all carcinogens containing oxygen is possible. Besides these emissions contain aromatics which have the same molecular formulas and perhaps the same structures as for metabolites of carcinogenic polycyclics have been determined up to now. Among these probably are also epoxides considered as proximate metabolites.

Two methods for the preparation of carbon black aerosols have been investigated: incomplete combustion of acetylene, acetylene + benzene and other hydrocarbons as well as a "resublimation" of amorphous carbon. The first method was developed for generating soot aerosols in animal experiments, but the latter method needs more basic investigation. Using radioactive acetylene and benzene the produced soot aerosol could be labelled by 14C. Benzo(a)pyrene aerosol was prepared by means of a vapour condensation and was also radioactive labelled. With a combination of both generators, a combined carbon black and benzo(a)pyrene aerosol was prepared. The benzo(a)pyrene amounts bound to the soot were in the range of from 1 ng to 50 microgram per 1 mg soot. Experiments dealing with adsorption and desorbtion of benzo(a)pyrene on soot in the gas phase have shown, that benzo(a)pyrene is relatively tightly adsorbed and cannot be easily or completely desorbed.

In an industrial area with heavy metal-processing industry investigations were made on 203 children with surgical diseases, questioning whether there is a correlation between blood lead level on one hand, and kind of disease, season of year, load by lead fall-out in the residence on the other hand. A correlation between blood lead level and amount of lead fall-out in the residence of the patients could not be proved.--Seasonal changes did not influence the height of the average blood lead level.--Stress situations like operations and serious diseases had no significant influence either. Parallel determination of 139 blood samples in two institutes showed essential differences in the individual results.--Conclusions of earlier investigators in the same industrial area could not be proved in essential items as mentioned above.

An epidemiological study of 413 randomly chosen children in age of 2--14 years living in an industrial town is presented. According to their place of residence they were either burdened with cadmium from a forge or with lead from the traffic. The different burden was refelcted not only in the blood lead level but also in blood cadmium level respectively. Both contaminants showed in their separate effects the same behaviour. The intensity of the absorption of lead or cadmium respectively influences not only the relationship between blood lead level or blood cadmium level and the other parameters (Pb-H, Pb-U, Cd-H, Cd-U, d-ALA-U) but also the distribution of these parameters.

The efficacy of 14 procedures for the hygienic disinfection of hands mostly with commerical preparations was tested by a new experimental model developed at the Institute of Hygiene of the university Vienna (1,3). The disinfectant power was clearly dependent on the duration of treatment as well as on the kind of alcohol used in the preparation (n-Propanol better than iso-Propanol better than Ethanol). After one minute the efficacy of all preparations containing one of the three alcohols as active agent was well comparable to that of the standard procedure which according to our proposal (5) uses iso-Propanol 60% (ml/ml) for 1 minute. For preparations with n-Propanol as the main active agent (Satinazid and Sterillium) this was true even after treatment for a period as short as 0.5 min. In our opinion disinfecting detergents are out of place for hygienic disinfection of hands. One preparation representing this group (Versuchspräparat A) was far less effective than the standard procedure.

A method is given to calculate the equilibrium concentrations of the molecules and ions emerging from the hydrolysis and dissociation of chlorine and bromine in aqueous soltuion. The differing influence the pH value and the initial (total) halogene concentration exerts to the HOX- and X2-equilibrium concentration is discussed. From the calculated equilibrium concentrations and tabulated standard reduction potentials the redox potentials of chlorine and bromine solutions at various pH values are calculated. No correlation between the reactivity and the redox potential of the two halogens was observed. Two possible explanations for the differing reactivity of chlorine and bromine against proteins are presented.