A new stamp method is described, which applies parts from so-called "Kratzenbürsten" from the textile industry. By this method colonies, growing on rodac-plates or membrane filters, can be transferred on selective culture mediums. By simple and quick appliance the quantitative and qualitative differentiation of hospital germs is possible.
The sensitiveness of viruses to gamma rays was compared using eight viruses suspended with low concentration in drinking water, and four viruses present in high concentrations in tissue culture medium. The results show that the following factors are responsible for the resistance of viruses to gamma rays: 1. type of virus: the specific radiation resistance varied considerably; in general, there was a closer correlation with the general resistance of the virus to chemico-physical influences than with the type of nucleic acid of the virus examined; 2. medium of suspension and state of aggregation: high protein content and lyophilisation increased the resistance to gamma rays widely; 3. virus concentration: the virus reduction by a factor of 10 in suspensions with high virus concentration needed a higher radiation dose compared with suspensions of low virus content. All the results demonstrate the kinetics of inactivation to be a 1st order reaction. The increase of temperature to 41 degrees C did not show any significant influence.
Sewage treatment plants show only a 90-99% reduction in numbers of salmonellae. And the following chlorination of the effluents produces chlorinated organic derivatives and these are likely to be of great long term environmental danger. Thus for reasons of hygiene, it is desirable to study biological methods to remove salmonellae in waste waster. Therefore, the efficiency of the Felix O 1-bacteriophage for the removal of S. schottmuelleri and S. typhimurium was investigated. The composition and the pH of the medium (Destilled water, Sörensen phosphate buffer solution, pH 6.0-8.0, and sterilized wate water, pH 6.5) seem not to have a considerable importance for the observed salmonellae removal efficiency. As it is shown, the reduction of salmonellae by the O 1-phages is dependent on their concentration (Fig. 1). It is true, there is 90-99% removal of salmonellae as a function of their concentration, but a perfect elimination is not possible.
In this study we have tried to characterize the inhibitory power of Lactobacilli of meat origin. We selected 28 Lactobacillus strains isolated at various stages of sausage manufacture (mixed, baked, dried). These strains were tested for their inhibitive activity on gram negative bacteria (Pseudomonas fluorescens; Ps. aeruginosa, Escherichia coli B 41 enteropathogenic). It appears that the Lactobacillus strains synthetize one or more inhibitive substances instable in cold or heat, sensitive to the enzyme activity of peroxidase and to certain proteolytic enzymes (protease isolated from Bacillus subtilis and pepsin). Moreover, this inhibitive activity is associated with the bacterial walls. The instability of these inhibitors leads us to think of peroxide type substances; our results show that it is not hydrogen peroxide but, without doubt, far more complex peroxides associated to a proteinic structure which conditions their activity.
Water of basins and filters taken from 9 indoor-pools and 5 heated outdoor-pools has been tested for free-living amoebae by means of filtration and subsequent cultivation on agar and in fluid media. In 94.6% of the samples taken from basins and in 60.7% of the samples taken from flushing back filter water, amoebae could be cultivated which all belonged to the genus of Acanthamoeba. They were tested for pathogenic symptoms by means of mouse inoculation tests, temperature tolerance tests, cross-reaction in the immunofluorescence test, and on tissue culture. 19 strains of amoebae could be re-isolated from lungs and brains of healthy mice. Only after the third series of inoculation from animal to animal, for mice characteristic pathogenic symptoms could be observed. The importance of acanthamoebae in swimming pools to the health of men cannot be estimated yet. But existing findings did not deliver reason for grave concern.
Airborne particulate matter was collected on filters at various times in Duisburg, Duesseldorf, Muenster and in 2 rural areas. After extraction with organic solvents the extract was partly fractionated and analyzed for BaP and 7 other polycyclic aromatic hydrocarbons (PAH). The carcinogenicity was examined with the subcutaneous test using 7000 mice in total. The amount of extract required was relatively small. Extracts from suspended matter with a BaP content of 0.37 to 1.1 microgram BaP brought about tumour rates in the range of 30%. On account of the results the following can be concluded: 1. The total extract of atmospheric particulates results in definite dose-response relationship, when the part of the compounds not belonging to the PAH is rather low. 2. The PAH fractions derived from the suspended matter collected in different cities show the same carcinogenic potency, when they are adjusted to the same BaP level by means of concentration or dilution. 3. The PAH bear the most important share with respect to the carcinogenic potency of an extract from suspended matter. 4. Numerous compounds (polar substances) which are not classed with the PAH are carcinogenic to some extent, partly they are able to inhibit the carcinogenic effect. 5. The dose-response relationship of BaP is strongly leveled off in general when all the substances of an extract are present. That means when the dose of an extract is low, the importance of BaP becomes less. Therefore a fixed ratio concerning the effect of BaP within an extract cannot be given. It has to be examined in particular, which PAH and non-PAH are necessary to analyse in order to describe the carcinogenic effect due to an extract from airborne particulates. Much more attention is to be payed to the polar substances.
Many legal regulations exist on the hygienic-microbiological properties of food products. The 'Länder-Speiseeisverordnungen' (County Ice Cream Regulations), the 'Diät-Verordnung' (Dietary Regulation) and the 'Trinkwasser-Verordnung' (Regulation on Potable Water) are examples for the frequent inadequacies inherent in these regulations. Caution is indicated against any new proposals for the establishment of additional hygienic-microbiological regulations without sufficient practice-related reasoning unless a revision and improvement of inadequate, already existing regulations has been carried out. Practicable procedures have to be prepared not only to maintain the hygiene in Catering facilities, but also for the evaluation of food products and raw materials according to hygienic-microbiological criteria: Although commonly assumed, the 'Microbe Counts' alone are not sufficient for the determination of the hygienic conditions. Therefore, inspite of all the weak points inherent in quality control procedures - e. g. possible sick, co-workers, only random sample control of raw material supplies - such adapted systems (good manufacturing practice) have to be enforced with special emphasis on the economy of the control expenditure, interdisciplinary aspects, governmental control and consumer information. Examples from literature and own experience demonstrate that the importance of the 'Fecal Indicators' for the judgement of 'hygienic conditions' in food production are rather limited and a correct evaluation only by 'Bacterial Plate Counts' is not possible due to the variation of germ density within one sample. Microbiological investigations of food products according to statistic rules require such an expenditure that they cannot generally be used as routine control procedures. A possible documentation is shown which allows - even without statistic investigations, at least retrospectively - the preparation of a survey on the microbiological properties of raw materials generally available on the market and which makes it possible to recognize and reject any unqualified microbiological limiting value requirements.
115mCdCl2 was nebulized by a jet nebulizer, yielding an aerosol concentration of Cd of 660 ng/l. Rats were exposed nose only for 1 h. For the instillation study 115mCdCl2 was instilled intracheally, 8 microgram in 0.3 ml NaCl. Rats of both studies were serially sacrificed from day 0-100, and the lung activity was counted. The results showed a bi-exponential clearance pattern in both studies, where the long clearance gave half lives of 61 d (inhalation) and 66 d (instillation), respectively. The short term clearance half lives were 1.1 d (inhalation) and 0.7 d (instillation). About half of the deposited Cd is cleared in both studies in the fast phase. After inhalation, 16% more Cd was deposited in the alveolar area as compared to instillation. It was found that on the second day after instillation of CdCl2 only 2% could be lavaged out of the lungs, suggesting a protein binding of Cd in the lung.
An investigation on the relationship between dietary arsenic exposure and cardiovascular diseases was made. In Antofagasta Commune, northern Chile, since 1955 arsenic has polluted public drinking water. This environmental contamination is of geological origin. The concentration of arsenic in drinking water for the 1955-1970 period was 0.5980 ppm (weighted mean). In the period June 1970-March 1972, the concentration decreased to 0.0815 ppm (weighted mean), due to a Water Filtration Plant which started operating in May 1970. Greater Santiago showed 0.00 ppm of arsenic in drinking water. Amongst 10 autopsied patients (age range: 1 year 7 months to 18 years) with chronic arsenical dermatosis from Antofagasta Commune, 9 showed marked fibrous intimal thickening of the arterial wall and/or restricted lumen of the left coronary artery, 2 of these 9 also exhibiting myocardial infarction. Of the 10 patients, 7 developed cardiomegaly, which was related to chronic exposure to dietary arsenic. Two series of patients with myocardial infarction under 40 years of age, one from Antofagasta Commune (exposed to arsenic), the other from Greater Santiago (not exposed to arsenic) were compared. The Yates' corrected chi 2 value (1 d.f.) being 11.7776. The difference was statistically highly significant (P approximately equal to 0.0006018). Furthermore, in Antofagasta Commune, the number of cases (< 40 yr) which had myocardial infarction with chronic arsenical dermatosis were compared with the cases (< 40 yr) which showed myocardial infarction without chronic arsenical dermatosis. The Yates' corrected chi 2 value (1 d.f.) was 13.0395. A highly significant difference was detected (P approximately equal to 0.0003044). Children (0-15 yr)from the two cities were also compared.(ABSTRACT TRUNCATED AT 250 WORDS)
A large number of bacteria were characterized and identified using a miniturized multi-test system and an automatic inoculator. This testsystem is suitable for ecological studies to get information about the qualitative and quantitative composition of bacterial populations. More than that a biochemical typing of bacteria is possible.
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