SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
During recent years evidence has been accumulated supporting the hypothesis according to which nitroso compounds are involved in the generation of stomach cancer in humans. The present report deals with the occurrence and content of nitrite, nitrate and nitrosamines in the gastric juice of stomach cancer patients with special reference to nitrate-reducing microorganisms. Microorganisms were found to be present in gastric juice in all cases of cancer, mean total count being (5.6 +/- 2.4) log/ml (mean +/- standard deviation) and with limit values 1.4-8.0 log/ml. Nitrate-reducing microorganisms were found in 9 cases from 10. Their mean counts were (5.2 +/- 2.5) log/ml and limit values less than 0.5-8.0 log/ml. The role of nitrate-reducing microorganisms in the formation of nitrite and carcinogenic nitroso compounds is discussed. Some practical measures to control the count of nitrate-reducing microorganisms in stomach are presented.
Specification for the preparation of a biological indicator (BI) using two or more microorganisms in the carrier material were deleted from the current ISO 11138 series and Working Draft 14161 because it was assumed that the resistances of the individual microorganisms would be affected by interference from the other microorganisms. This assumption is speculative only, and has not been supported by experimental evidence. To test its validity, the author carried out an experiment to determine the resistances of Bacillus subtilis and Bacillus stearothermophilus when used alone and together in BI carrier material. In total concentrations of 10(6) cfu/0.1 mL, the organisms were applied alone and together to filter paper and dried. After incorporation into the BI, the three preparations (B. subtilis alone, B. stearothermophilus alone, and both together) were subjected to ethylene oxide sterilization or to moist-heat sterilization using the procedures described in ISO 11138-2 or ISO 11138-3, respectively. Resistances were measured in terms of decimal reduction times (D values). The D values of the preparations were determined using the survival-curve method and the limited Spearman-Karber method in conjunction with a BI evaluator resistometer. The D values of the preparations did not differ significantly with either sterilization method, providing experimental evidence that, at least under these conditions, the presence of a second microorganism in the carrier material did not interfere with the resistance of the original microorganism.
The viable micropopulation at three altitudes (152, 1,066, and 1,981 meters) of a land air mass as it traversed an ocean was determined. At the low altitude, a consistent pattern of decrease in numbers of land-originating microorganisms with increasing distance from shore was observed. At the higher altitudes, the observed pattern was one of irregularity. At the lower altitude the percentages of bacteria and fungi were approximately equal near the coast, but as distance from the coast increased, fungi predominated over the bacteria at all sampling locations. The greatest number of different genera of both bacteria and fungi were obtained at or near the coast. Fungi of the genera Alternaria, Hormodendron, Penicillium, and Aspergillus, and bacteria of the genera Micrococcus and Bacterium predominated at all altitudes and locations.
In the present study we identified a gram-negative anaerobic rod referred to as Y4 which was cytotoxic for human polymorphonuclear leukocytes. Y4 was isolated from dental plaque of a patient with juvenile periodontitis and presented most of the taxonomic characteristics of Actinobacillus species. Under experimental conditions, viable Y4 were cytotoxic for human peripheral blood polymorphonuclear leukocytes in serum-free cultures. Cytotoxicity was dependent on bacterial concentrations and was enhanced in the presence of a fresh or heat-inactivated (56 degrees C, 30 min) autologous serum. Leukotoxicity was independent of phagocytosis. Y4 leukotoxic effect was abolished when bacteria were heat treated (56 degrees C, 30 min) or when incubations were carried out at 4 degrees C instead of at 37 degrees C. The leukotoxicity was monitored by electron microscopy and biochemically by measuring lactate dehydrogenase indicator of cell viability. No cytotoxic effects of Y4 on human mononuclear cells, chicken fibroblasts, or mouse macrophages were detected under the conditions studied. Polymorphonuclear leukocytes may play an important role in the host defense against bacteria in periodontal disease. The cytotoxic effect of Y4 for polymorphonuclear leukocytes presented in this study is the first report of a direct offensive microbial vector in a plaque-derived microorganism and may prove to be relevant in the pathogenesis of juvenile periodontitis.
Microorganisms producing anti-inflammatory substances were screened by the inhibitory effect on mast cell degranulation. Three new compounds related to pentaene macrolide eurocidins, eurocidins C, D and E, have been isolated from the culture broth of Streptoverticillium eurocidicum IFO 13491 as the inhibitors. Their molecular weights and molecular formulae were estimated as 781.89 and C39H59NO15 for eurocidin C, 795.92 and C40H61NO15 for eurocidin D, and 779.92 and C40H61NO14 for eurocidin E, respectively.
Serological study of 788 blood sera, taken from residents of the Moscow region was conducted using antigens of microorganisms of the genera Rickettsia and Bartonella. The first group under examination consisted of 355 patients with diagnosed diseases of nonreckettsial nature. The second group includes 433 healthy adults working at a meat processing and packing factory. The main method used for sera survey was the indirect immunofluorescence test. In the sera taken from the first group of subjects specific antibodies to R. prowazekii, R. typhi, B. quintana, B. henselae antigens were detected in 2.3%, 5.1%, 4.0% and 2.9% of serum samples respectively. In the serum samples taken from the second group the proportion of antibodies to R. prowazekii, R. typhi, B. quintana, B. henselae antigens was different: 0.5%, 3.3%, 1.7% and 4.0% respectively. In total, specific antibodies to R. typhi and B. henselae prevailed over specific antibodies to R. prowazekii and B. quintana twofold.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The viable micropopulation found, at altitude over a city, in a land air mass was significantly higher than that found in a marine-influenced air mass. The percentage distribution of bacteria and fungi was approximately equal in both types of air masses. This indicates that, under the conditions of the experiment, the marine air mass was influenced by the land area over which it traveled during passage from its source to the sampling area. Activities taking place within the city significantly increased the micropopulation at altitude. This increase was quantitatively so small that it was not identifiable when the micropopulation moving into the city was high-as in a land air mass-but was recognizable when the micropopulation was low-as in a marine-influenced air mass. The modification of the micropopulation at altitude by temperature inversions was shown.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.