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W Gräf

Publications and source records attributed to W Gräf.

At least 19 recordsLinked to original sources
PubMed1999

Tetrahymena pyriformis in the ciliate mobility test. Validation and description of a testing procedure for the registration of harmful substances in the air as well as the effects of cigarette smoke on the human respiratory ciliated epithelium.

The damage of the human respiratory ciliated epithelium or its ciliar activity caused by mixtures of harmful substances in the air and cigarette smoke is a considerable parameter for the judgment of acute harmful influences on the human respiratory tract. As an immediate measuring or a quantitative statement about the influence on cilia in vivo at human beings is extremely difficult and problematic, a convenient model experimental system in form of the so called ciliate mobility test (CMT) has been used. In this connection the influence on cilia of the protozan single-celled organism Tetrahymena pyriformis, regarding its average speed of locomotion has been taken as standard. The proof, that the cilia are identical in morphological and functional respect at the human ciliated epithelium and at T. pyriformis has been reached by electron optical comparative representation and bibliographical known substances, influencing cilia (theophylline, bromhexine, ambroxol, terpin hydrate, mercaptoethanesulfonat-sodium, amrinon, salbutamol, tetracosactid-hexaacetate, histamine, and phenol). With regard to the comparability and applicability to the human respiratory ciliated epithelium we have been able to gain statements by means of the CMT. By constructing a special reaction vessel the influence of harmful gases at a thin layer of ciliate culture suspension (1 cm) for a standardised exposure time (1 hour) has been made possible and with that a model for the comparability with the conditions of the human respiratory ciliated epithelium has been created. A number of harmful gases, that are relevant in the air hygiene (CO, CO2, N2, N2O, NO2, O3, SO2) as well as cigarette smoke at active smokers (primary stream smoke) and the inhalation of the smoke of other people's cigarettes has been tested. It turned out, that especially NO2 (nitric oxide) shows a high ciliar toxicity, while the controversially discussed ozone (O3) has not resulted in detraction of cilia. CO, N2O and SO2 have been--to a great extent--harmless on cilia in the concentration range relevant in the air hygiene. Remarkable are the results, that cigarette smoke shows clear toxic effects on cilia both at active smoking, as well as the inhalation of the smoke of other people's cigarettes. With that another contribution to the discussion about the harmfulness of active smoking and the inhalation of the smoke of other people's cigarettes is made.

Animals↗
PubMed1995

[Hygienic processing of dental transmission instruments (handpieces and instruments, turbines) in dental practice].

The efficacy of a steam disinfection method for the processing of used instruments in dental practice was tested with 274 high-speed turbines and handpieces. The instruments treated with streaming steam were both taken out of the dental practice of treatment and artificially contaminated with five different test-microorganisms (E. coli, P. aeruginosa, S. aureus, E. faecium, C. albicans) and different concentrations of serum (1%, 10%, 20%). In spite of the narrow channels of these instruments a microbial reduction of more than 5 log10 steps could be achieved in all cases. Thus dental high-speed turbines and handpieces can reliably be disinfected with streaming steam.

Colony Count, Microbial↗
PubMed1988

[Microbial contamination of liquid-soap wall dispensers with one-way bottles].

Hygienic examinations were performed relating to microbial contaminations of different kinds of fluid soaps in relation to various systems of dispensers. Totally 492 specimens of fluid soap were examined comprising 14 different kinds of trade names (Code A-O), sampled in 14 different hospitals including 4 different systems of dispensers. Out of 14 trade name products--containing antimicrobial additives--8 proved to be sterile. The rest--declared as free from antimicrobial additives--showed bacterial contaminations of different grade. One of them (Code "O"), without antimicrobial additives) proved to be excessively contaminated with P. cepacia in 108 specimens out of 281, i.e. 38% in the range from 10(3)-10(6) CFU/ml. Further investigations on origin and mechanism of this alarming event revealed, that the cause for this dilemma was a failure in the dosing system of the one-way bottle dispensers used. This seems to be of fundamental importance for a great number of one-way-dispensers used at presence for fluid soaps or disinfectants: Changing only the emptied bottles out of the wall-attached device of dispenser causes inevitably a rapid recontamination of the new bottles, if not the dosing-device is as well removed and effectively cleaned and disinfected before reinserting.

Bacteria↗
PubMed1985

[Phototoxic effect of polycyclic aromatic compounds on human fibroblast cultures].

The phototoxic effects of polycyclic aromatic hydrocarbons (PAH) benzo(a)pyrene, benzo(a)anthrazene, indeno(1,2,3-cd)pyrene, fluoranthene and perylene, and their relation to the known carcinogenicity of these compounds was examined with human fibroblastic cultures. Using different light filters it could be demonstrated that phototoxic effects on the cell cultures only occur with wave lengths shorter than 400 nm, that is in the longwave UV-region. With wave lengths longer than 400 nm, that is in the visible region of light, no cytotoxic effects could be detected. Irradiated with long-wave UV, the highly cancerogenic compounds benzo(a)pyrene, and indeno(1,2,3-cd)pyrene proved to be highly cytotoxic, the moderately cancerogenic benzo(a)anthrazene turned out to be distintly cytotoxic, fluoranthene supposed to be not cancerogenic, proved to be only slightly cytotoxic. Perylene that is considered not cancerogenic either, reacted completely indifferent. These results are completely compatible with those obtained earlier with ciliata (unicellular protozoa). They confirm the assumption that the so-called ciliata test (Tetrahymena pyriformis) can be used as a practicable test system to ascertain the carcinogenicity of PAH.

Carcinogens↗
PubMed1984

[Gaps in asepsis due to surgical caps, face masks, external surfaces of infusion bottles and sterile wrappers of disposable articles].

It is obvious that the surfaces of the boxes of sterile packed disposable instruments and infusion bottles are not sterile. The disposable surgical masks and surgical caps used for sterile clothing are delivered by the producers not sterile, either. To quantify these gaps and to judge their risks in the aseptic region the surfaces of 117 sterile packed disposable instruments and the inner sides of their boxes were examined bacteriologically. The surfaces of these objects proved to be not sterile by 21% and 4% were heavily contaminated with saprophytic germs. 3% of the examined articles showed pathogenic germs like Clostridium perfringens, Staphylococcus aureus, and Acinetobacter spec. 5-15% of the surfaces (glass- respectively plastic and labels) of the 331 infusion bottles proved to be heavily bacteriologically contaminated; 4-6% of them even showing pathogenic germs like Clostridium perfringens, Staphylococcus aureus, and Achromobacter spec. The surfaces of 25% of the examined disposable surgical masks and caps were considerably contaminated with saprophytic germs. Although pathogenic germs could not be detected, it means that these not sterile objects represent a considerable deficiency in surgical asepsis.

Acinetobacter↗
PubMed1983

[Microbial colonization of the nasopharynx, external auditory canal, hair of the head and armpit in high performance swimmers].

From 50 high-performance swimmers, who were subdivided into three training groups, swabs were taken before and after the swimming training from the nose, throat and the external auditory canal, and bacterial samples were taken according to the Rodac method from the hair of the head and the armpit for a quantitative and qualitative analysis. - No significant quantitation differences were found to exist in the bacterial flora before and after the swimming training, except for the external auditory canal where the bacterial population had increased, and the armpit where it had diminished. - A qualitative comparison of the normal flora revealed no noticeable differences in the population before and after the swimming training for the three training groups. - However, differences in the pathogenic flora were identified in the three training groups. A higher germ count was found in those swimmers who had been training more intensely for a longer period of time than the members of a junior training group. This finding is particularly striking for P. aeruginosa which was located in the ears of those high-performance swimmers who belonged to the group with the most intensive swimming training. The carriers of Staph. aureus accounted for 46 per cent of the test persons. This species had primarily settled in the vestibule of the nose. - The swimming training hardly influences the invasion of the hair of the head with pathogens. The compulsory use of bathing cap serves general hygienic aspects rather than prophylactic hygienic purposes.

Adolescent↗
PubMed1981

[Hygienic and microbiological influences exerted on natural water biotopes by algae and the growth of water plants. 1. Communication: antibacterial properties of three water algae (Hydrodictyon reticulatum, Chlorella vulgaris, Aphanothece nidulans) in vitro (author's transl)].

The growth-inhibiting behaviour of abacterial, liquid pure cultures made up of three water algae (Hydrodictyon reticulatum, Chlorella vulgaris, Aphanothece nidulans) which were made to grow profusely in special culture containers under constant exposure to light and ventilation was examined in ten different species of microorganisms during a period of contact of 4 days both in the light and in the dark. Subjected to the test were the 5 pathogenic species Staphylococcus aureus, Klebsiella aerogenes, Pseudomonas aeruginosa, Salmonella typhimurium and Candida albicans as well the 5 bacterial contamination indicators E. coli (faecal indicator), Streptococcus faecalis (enterococci), Enterobacter aerogenes ("coliforms"), Staphylococcus epidermidis (dermic germ) and Bacillus subtilis ("contamination germ"). It was found that --Hydrodictyon reticulatum and Aphanothece nidulans exert a strong antibacterial effect, while Chlorella vulgaris provides no indication of a bacterial growth-inhibiting effect. --this antibiosis is linked with the assimilative activity of the algal cultures, as in the dark no antibacterial action is discernible --the "antibiotic principle" must be liable to transitory or rapid disintegration because the algal cultures are ineffective in the dark and also culture filtrates of 5-days old algal cultures exercise no growth-inhibiting effect. With respect to the sanitation of waters it is important to state that a profuse growth of algae produces a certain, but hardly reliable "biological water disinfection" and renders difficult the assessment of the quality of a water-course as a result of the elimination of the usual contamination indicators. Therefore, additional microbiological quality parameters must be used for assessment of pollution of swimming pools with strong algal growth.

Bacillus subtilis↗
PubMed1981

[Infection risk through the reuse of "used" cylinder ampoules for dental local anaesthesia (author's transl)].

The phenomenon of so-called syringe internal infection with cylinder ampoule syringes customarily used in dental local anaesthesia is discussed from the view-point of infection hygiene. The contamination rate of the residual content-of used cylinder ampoules has been determined by means of bacteriological model tests with E. coli under the conditions of the cannulae removal phenomenon and the reflux phenomenon caused by tissue overpressure resulting from the injection. It has been shown that - as result of changing a contaminated cannula with the commonly used Uniject cylinder ampoule injection system, the probability that the cylinder ampoule residual contents are infected in 93% using metallic head cannulae and 78% with disposable screw-on cannulae; - even with the lever syringe systems for intraligamentary anaesthesia, changing contaminated, ultra-thin special cannulae leads with 11-12% probability to infection of the cylinder ampoule residual contents; - injections with a tissue counterpressure of only 1 atm result in a 100% contamination rate of the cylinder ampoules through reflux phenomena. The test results lead to the indispensable hygienic demand that - irrespective of which injection system is used - used cylinder ampoules must not be reused with other patients. The increasingly high contamination ratio (0.5 - 1.0%) of our population with hepatitis B viruses places increased demands on the need for care on the part of the dentist and physician.

Anesthesia, Dental↗
PubMed1981

[Hygienic and microbiological influences exerted on natural water biotopes by algae and the growth of water plants. 2. Communication: improvement of the chemical and bacteriological water quality by the natural growth of aquatic plants (author's transl)].

For a natural pond, whose waters are used for recreational purposes (swimming) and are subject to waste water inflow, the biological purifying function of a zone overgrown with reeds and aquatic plants was ascertained by means of chemical and bacteriological water quality parameters. In the years from 1975 to 1980 the contents of ammonia, nitrites, nitrates, phosphates and chlorides as well as the colony counts (CFU/ml), the coli titres (direct faecal indicator) and the content of fruiting myxobacteria (indirect faecal indicator) were determined from water samples, both during the lush-growth summer period and the low-growth winter season. The location of the 6 sampling points systematically extended from the sewage outlet via the tributary ditch, in front of and behind the natural growth zone as far as the swimming waters. The test series showed - that in the tributary ditch and especially during the passage through the upper water zone densely overgrown with aquatic plants, the proportion of degradable nitrogen compounds and phosphates is distinctly reduced beyond the extent of reduction by dilution processes, - that the colony counts in the effluent water as well as the content of E. coli and of the fruiting myxobacteria, which act as indirect faecal indicator, are also reduced considerably, - that the biological purifying of the vegetation zone is definitely higher in summer than during the low-growth winter months. From this the conclusion can be drawn that for maintaining and furthering an adequate water quality of recreational waters compromised by waste water, the preservation of the naturally growing aquatic plants both in the water itself and on the banks is absolutely necessary.

Ammonia↗
PubMed1980

[Bacteriological evaluation of surgical masks (author's transl)].

An experimental set-up is described permitting the evaluation and quantification under controlled conditions of retention efficiencies of surgical mask materials and different types of masks, using bacterial aerosols standardized both quantitatively and qualitatively. Screening of various materials used in one-way surgical paper masks has shown that, apart from the one-layered thin models, present paper masks with bacterial transmittance under 1% are far superior to the muslin masks of the past. For meeting the aseptical requirements in hospital operating rooms, adaptable masks (green exterior) provided with multi-layered polyester filter pads have proven most suitable by their virtual impenetrability for bacteria. After several hours use and heavy wetting of the filters layers, no increase of bacterial transmittance was observed.

Bacteria↗
PubMed1980

[Effect of the lead-petrol-law on the contents of lead and benzo(a)pyren in urban environmental dust (author's transl)].

For the purpose of evaluating the stress on citydwellers by pollutants emanating from traffic sources the contents of lead and 3,4-benzpyrene in sedimentable city dust were determined in samples collected at 46 sites with different traffic densities in a city of medium size but considerable overall traffic volume (Erlangen, Bavaria). To estimate the effect of the gasoline-lead-law of Aug 5, 1971, determinations were carried out both in 1971, i.e. before this law came into effect, and in 1977 when the lead content in gasoline was finally limited to 0.15 g/1. The following results were obtained: - In city areas with dense traffic, the medium lead content dropped from 4.2 to 2.2 mg/g of dust, and the medium 3,4-benzpyrene concentration dropped from 1.3 to 0.5 microgram/g of dust. This amounts to a reduction of both the lead and 3,4-benzpyrene contents in city dust by about one half. - In the city periphery with lesser traffic density, the lead and benzpyrene contents, resp., were originally lower by about one half. In the case of lead, the concentration dropped from 1.9 mg to 1.2 mg/g dust, while 3,4-benzpyrene dropped from 0.6 to 0.4 microgram/g dust. Thus, the beneficial effect of the gasoline-lead-law was less obvious in these low-traffic parts of the city area. - The decrease in 3,4-benzpyrene with decreasing lead content is remarkable (striking, a striking pheromeron) and may be explained by lesser emission of this pollutant when burning gasoline low in lead.

Automobiles↗
PubMed1979

[Aquatic myxobacteria as indicators in the evaluation of drinking water quality (author's transl))].

Aquatic myxobacteria were shown to be good indicators of surface contamination of drinking water, or water filtered by an inadequate soil profile, both in experiments with sterilized or biologically active soil profiles, resp., and in actual comparison data obtained in practical drinking water analyses. In experimental investigations with artificial profiles, aquatic myxobacteria were retained to a considerably greater degree than E. coli or P. fluorescens due to stronger forces of adhesion. In a number of bacteriological drinking water analyses, this property was confirmed insofar as aquatic myxobacteria could regularly be demonstrated when inspecting hygienically deficient wells or springs. The confirmed presence of E. coli, on the other hand, showed a considerably lesser correlation with the results of on the spot evaluations of hygienic conditions. It must be urgently advised to include the search for aquatic myxobacteria in bacteriological drinking water analyses, since, contrary to the demonstration of E. coli, not only the actual but, in addition, the potential hazard of contamination of drinking water with bacteria present in superficial soil strata is indicated.

Bacteriological Techniques↗
PubMed1979

[Aquatic myxobacteria (Sporocytophaga cauliformis) and the order "Myxobacterales" (author's transl)].

The indicator function of aquatic myxobacteria for the purpose of evaluating drinking water quality as well as their occurrence in sewage effluent make it desirable to describe these hitherto little known organisms in more detail. To this end, a comparative investigation of anaerobic myxobacteria of the genus Sphaerocytophaga, two typical representatives of the Order Myxobacterales (Myxococcus fulvus, Sporocytophage cauliformis), and a strain ov Vitrepscilla (Vitroescilla proteolytica) was undertaken. With respect to culture morphology, the migratory fringe surrounding colonies of Sphaerocytophaga similar to the other strains studies was a prominent characteristic. In particular, the similarity with colonies of Sporocytophaga cauliformis was apparent. The gliding motility typical of Sphaerocytophaga could be demonstrated in all of the strains investigated. Scanning electron micrographs revealed an amorphous layer of slime covering the cell surfaces in all strains compared in this study, thus excluding the existence of more rigid organelles of locomotion. Taxonomically, the anaerobec myxobacteria of the oral cavity (Sphaerocytophaga) belong to the Order "Myxobacterales" and not the "Eubacterales", i.e., to the genus Fusobacterium. This is clearly suggested by their motility lacking flagella and, above all, by their cell morphology which differs from the Eubacterales.

Culture Media↗
PubMed1979

[Rate of dental caries in youths from communities of both naturally high and low, resp., fluoride content in drinking water (author's transl)].

The incidence of caries in terms of the so-called DFS (= Decayed filled surfaces) index was ascertained for test persons aged from 6 to 15 years, in a community with a drinking water supply having a naturally increased fluoride content (Falkenberg/Oberpfalz, 1.8 ppm F') in comparison with test persons from a neighbouring community with a drinking water supply having a low-fluoride content (Fuchsmühl/Oberpfalz, 0.05 ppm F'). In 103 persons tested (corresponding to 7,577 dental surfaces surveyed) from Falkenberg, the DES index was 5.3, in 123 test persons (corresponding to 10,473 dental surfaces surveyed) from Fuchsmühl the DFS index was 12.4, which means that the naturally increased fluoride content of the drinking water caused caries to drop by 58 per cent viv-à-vis the reference group. No appreciable differences were found to exist in the eruption times of the permanent teeth in both groups of test persons, i. e. fluoride in drinking water does not appear to delay the eruption of teeth. The incidence of fluoride-induced enamel hypoplasia as determined by Kunz on the same test persons, resulted in a distinct increase of 74 per cent for the "fluoride group" vis-à-vis the reference group with a 33 per cent increase only.

Adolescent↗