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Biomedical subjects

M Exner

Publications and source records attributed to M Exner.

At least 145 records · Page 8Linked to original sources

[The occurrence of perchloroethylene in indoor air and food in dwellings in the vicinity of dry cleaning plants].

In this presentation the results of investigations concerning the concentration of Tetrachloroethylene in indoor-air and in food in residential quarters in the vicinity of dry cleaners are reported. It could be demonstrated that a significant enrichment of Tetrachloroethylene becomes evident in fat containing food, increasing with the time of storage. Particularly in butter the limit of concentration admissible for the consumption of food was exceeded in four out of five apartments after seven days. The examination of the concentration of Tetrachloroethylene over the course of the day indicates that in dependence of the hours of operation significant differences were measurable in the concentration of Tetrachloroethylene in the indoor-air of an apartment examined, without indoor rooms building up accumulation of Tetrachloroethylene. The investigations confirm that residents in the neighbourhood of dry cleaners are exposed to high load of Tetrachloroethylene by indoor-air and food.

Air Pollutants↗

[The effectiveness of intratracheal antibiotic administration. Clinical, microbiologic and pharmacologic results].

In 199 artificially ventilated patients of an internal intensive care unit clinical, bacteriological and pharmacological effects of endotracheally administered gentamicin were investigated. The dose schedule was 2-4 x 40 mg gentamicin/day. The incidence of secondary achieved pneumonia was reduced from 70% to 18%. The endotracheal colonization of pathogenic microorganisms reached 29.6% concerning bacterial microorganisms and 61% concerning fungi, 51.8% of all specimen were sterile. During 4 years of investigation there were found 19 secondary resistances of different bacteria, 12 persisted. Serum concentrations of gentamicin under endotracheal administration of 40 mg in 6-h-intervals didn't reach therapeutic values. In case of renal disorder the dose interval should be prolonged to twelve hours.

Adult↗

Influence of biofilms by chemical disinfectants and mechanical cleaning.

Water conducting systems in hospitals (endoscopes, nebulizers, tap water systems, dental units etc.) are often important reservoirs of conditional pathogens. The sanitation of those systems by in vitro efficient chemical disinfectants is very difficult. An explanation may be that microorganisms are growing in such systems in wall adhering biofilms wherein they are protected from biocides. A method for testing the efficacy of chemical disinfectants and mechanical cleaning is described under conditions which imitate those in natural systems. A criterion for the efficacy of sanitation procedure is not only the good disinfection result but also the removal of biofilms. The investigation showed that aldehydes, and peracetic acid can reduce multiplying microorganisms without disrupting the biofilm. A preparation on the basis of hydrogen peroxide showed good antimicrobial efficacy and a distinct reduction and influence of the biofilm. The best result was achieved by mechanical cleaning. The test model is simple and a supplement to the conventional in vitro laboratory test for the efficacy of sanitation procedures of water conducting systems.

Aldehydes↗

[Multiplication and killing temperatures of naturally occurring legionellas].

Suspensions of legionellae and associated bacteria found in a hot water distribution system were maintained in the exponential phase of growth without addition of nutrients by constant agitation and oxygenation and by periodically transferring them to autoclaved tap water. The suspensions were exposed to different temperatures to determine growth and inactivation kinetics of legionellae kept under conditions similar to their natural environment. Multiplication of the legionellae was found to occur in a temperature range between 20 and 43 degrees C and inactivation was observed above 50 degrees C. Decimal reduction times decreased with increasing temperatures. These findings do not support the hypothesis that naturally occurring legionellae are more heat resistant than strains of the bacterium cultured on artificial media. Frequent failure to eradicate legionellae from hot water systems by elevating the water temperature indicates that it is impossible to achieve effective temperature levels concomitantly in all parts of the system.

Bacteriological Techniques↗

[Nosocomial infection].

Sepsis is a systemic disease caused by pathogenic microorganisms and their toxic products in blood. Very often it is not possible to identify the pathogenic organisms before therapeutic treatment. Thus, diagnosis has to be made based on the patients' disposition as well as clinical symptoms. In septic patients clear alterations of plasma protein fractions are found. Depending on the clinical degree of severity, the low molecular proteins, detectable by column chromatography in plasma fraction III, are considerably increased. Population of implanted synthetic materials (such as catheters and cardiac valves) with facultative pathogenic microorganisms that may persist under antibiotic influence due to extracellular polymeric substances, is also of great importance. Therapy with antibiotic combinations is the most important therapeutic principle for sepsis and can be intensified by simultaneous administration of immunoglobulins.

Anti-Bacterial Agents↗

[Yeast fungus flora in tumor irradiation of the upper aerodigestive tract].

The microflora of the oral cavity and pharynx were examined in 28 patients undergoing radiotherapy for cancer of the upper aerodigestive tract. We found no correlation between yeast flora and mucositis: early mucositis occurred between 10 and 20 gy. independent of the concentration of yeast. During radiotherapy the number of patients with detectable yeasts rose from 12 to 22 of the 28. There was a tenfold increase of mean values for yeasts during irradiation, whereas the normal flora (eg. streptococci) remained unchanged. The value of an antifungal local therapy for the prevention of yeast-induced complications is discussed.

Adult↗

[Principles of the prevention of pneumonia by the intratracheal instillation of aminoglycoside antibiotics].

In long-term respiration the descension of the pharyngeal contents into the tracheobronchial system appears as unavoidable as the colonisation of the oropharynx with pathogens. On the other hand, elimination of the descended pathogens from the trachea and the bronchi by setting up an antibiotic barrier represented by the aminoglycoside antibiotics, can prevent colonisation of the lower respiratory passages. As a matter of fact, the aminoglycoside antibiotics exercise, first of all, rapid and bactericidal action, and secondly a spectrum of pathogens. Intratracheal application of 4 X 40 mg tobramycin daily, distributed over 24 hours, leads in the case of persons with healthy kidneys to serum levels between 0.4 and 0.7 micrograms/ml. Side effects are mainly seen in patients with restricted renal function in the form of cumulative serum concentrations. At present there are no alternative possibilities of prophylaxis against the sequels of descension.

Aminoglycosides↗

[Adhesion of mircroorganisms to respirator tubes].

Potentially pathogenic microorganisms may adhere to and persist on plastic surfaces by extracellular polymeric substances. Intubation tubes used between 30 minutes and 10 days in 14 ventilated patients of a medical intensive care unit were examined by scanning electron microscopy. All interior tube surfaces showed heavy colonisations which thus can persist over prolonged periods. The clinical relevance of these findings consists of the fact that, as on other plastic surfaces, microbial organisms may remain attached to ventilation tubes. Through formation of extracellular polymeric substances they are protected against effects of antibiotics and disinfectants. Aspiration of these microorganisms from the tubes may lead to pneumonias in ventilated patients.

Adhesiveness↗

Serum gentamicin concentrations during intratracheal administration.

In artificially ventilated patients, intratracheal aminoglycoside administration is used as a form of prophylaxis of broncho-pulmonary infections. In artificially ventilated patients with multiple organ failure, serum gentamicin concentrations were measured dependent on renal function after endotracheal administration. A standard commercial ampule of 40 mg gentamicin in a 1 ml solution was injected in undiluted form, intratracheally through the tubus , every 6 h. In the patients without renal failure, values over 1 microgram/ml were only found in certain individual cases and reached a maximum of 1.5 micrograms/ml. In patients with renal failure even after prolonged application, the average serum concentrations were between 2 and 3.5 micrograms/ml. In a very few cases, however, levels of up to 10.5 micrograms/ml were measured. The daily serum pattern revealed a distinct dependence on the administration; 1 h after administration there was an increase in the serum concentrations which decreased to the initial levels after 6 h. When patients with renal impairment are given an aminoglycoside intratracheally, serum levels of up to 10.5 micrograms/ml may be reached and thus additional systemic aminoglycoside therapy should be avoided.

Acute Kidney Injury↗

[Testing of mucosa disinfection methods in the mouth and throat. 1. Effect of chlorhexidine gluconate and PVP-iodine on alpha-hemolytic streptococci].

A method for testing a throat antiseptic procedure is described. As indicator bacteria alpha-hemolytic streptococci were chosen. Povidone-Iodine and Chlorhexidindigluconate (0.5% and 0.1%) and aqua dest. as control substance were tested by a mouthwash technique. The best reduction of alpha-hemolytic streptococci could be detected after mouthwashing by 0.5% Chlorhexidindigluconate (1.4 log reduction), whereas by Povidone-Iodine a reduction of 0.85 log steps was achieved.

Chlorhexidine↗