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Biomedical subjects

T Urban

Publications and source records attributed to T Urban.

At least 91 records · Page 5Linked to original sources
PubMed1983

Migration of Entamoeba histolytica under agarose.

A procedure for visualizing and quantifying motility of Entamoeba histolytica by migration under agarose is described. Agarose suspended in tissue culture medium 199 supplemented with bovine albumin was poured into plastic dishes and allowed to harden. Six pairs of wells were cut out in a circular configuration. To the inner wells a suspension of E. histolytica in Eagle's Medium (24 X 10(6) cells/ml) was added, and to the outer wells a chemoattractant or the control medium. After overnight incubation at 37 degrees C, the amebae were fixed and stained. The chemotactic and spontaneous migrations were measured in an enlarging projector. Escherichia coli filtrates, suspensions of intact and lysed erythrocytes, and the complement factor C5a acted as good chemoattractants. Both the random and chemotactic motility were correlated to the time of the incubation. Cytochalasin B effected a dose-related inhibition of both chemotactic and random migration, while colchicine caused a decrease of the chemotaxis only. The reproducibility of the method, measured by 10 intra-assay tests, was good. Thus, the described method can be useful for comparative determinations of the motility of different ameba populations. Furthermore, different factors affecting the motility of amebae can be studied.

Chemotaxis↗
PubMed1981

The influence of opsonization with specific antibody and complement on the nitroblue tetrazolium (NBT) reduction of neutrophil granulocytes. A methodological study and a clinical application.

The NBT reduction of granulocytes, increased in the presence of bacteria, was further enhanced bl specific antibody. The enhancement was dose-dependent and increased by complement. Clinically, the NBT test was used for measuring specific antibody in sera from patients after severe infections. With sera from 10 out of 14 patients with proven or suspected septicemia the NBT reduction was enhanced because of the presence of specific antibody. These results correlated well with the bacteriological findings and supported the view that the bacteria isolated from blood were relevant for the disease.

Antibodies, Bacterial↗
PubMed1979

Nitroblue tetrazolium (NBT) reduction by bacteria. Some properties of the reaction and its possible use.

All the S. albus, E. coli and P. aeruginosa strains examined reduced nitroblue tetrazolium (NBT) to dark blue formazan. The amount of formazan produced was proportional to the number of bacteria. Under the same growth conditions, an equal number of bacteria of various strains produced different amounts of formazan. However, there were statistically verified differences in the NBT-reduction between the three species examined. The NBT-reduction took place in all phases of growth but was most intense in the early logarithmic phase. NBT was found to be toxic for bacteria, and the different strains had varying sensitivity to that effect. The NBT-reaction was markedly enhanced by phenazine methosulphate (PMS). The blue colour of formazan produced from NBT has an advantage over the red colour from triphenyltetrazolium chloride (TTC) if the reaction occurs in the presence of haemoglobin often present in biological materials. With NBT and PMS, 10(6)--10(7) bacteria are needed to form detectable amounts of formazan. The NBT-reduction by bacteria may be useful for measuring the influence of bactericidal, bacteriostatic or growth-stimulating factors on bacteria.

Bacteria↗
PubMed1978

Nitroblue tetrazolium (NBT) reduction by bacteria employed for rapid determination of antibiotic concentrations in serum.

The ability of bacteria to reduce nitroblue tetrazolium (NBT) to formazan, and the inhibition of this process by antibiotics, have been utilized in a method to determine antibiotic concentrations in serum. Escherichia coli, growing in the presence of increasing but subinhibitory concentrations of antibiotics, produces diminished amounts of formazan. This is photometrically quantified and the optical density obtained with the sample is compared with those obtained with know concentrations. Levels of aminoglycosides below 1 microgram/ml can be measured in the presence of other antibiotics also, and the assay can be carried out in three hours. Good correlation was obtained when 49 serum samples containing varying concentrations of sisomicin were tested simultaneously by the NBT assay and a disc diffusion method.

Aminoglycosides↗
PubMed1977

[Dust-measurements in the air of school-sporthalls (author's transl)].

Corresponding to the importance of sport in infancy and youth there were made experimental studies to examine the load of dust in school-sporthalls. In one selected school-sporthall of Erfurt 900 dust-measurements with Zeiss-Conimeter type 10 were carried out for a half-year in winter, and supplementary it was measured with the soviet conimeter type A 3-4 some days. The statistical evaluation allowed a break down of the sport-exercises in 3 groups dependent of the lot airborne dust in the sporthall: 1. gymnastic with apparatus 2. physical training on-floor 3. running and plays. The average quantities of dust during these three above mentioned exercises increase from group 1 to group 3, and they differ significantly. The results are discussed in connection with the literature which for the greater part originates from Poland and Soviet Union.

Air↗