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Biomedical subjects

W Presber

Publications and source records attributed to W Presber.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Determination of serum- and phagocyte resistance of E. coli using bioluminescence].

Resistance to serum and phagocytosis belong to the most important virulence markers of the bacteria. These properties enable the microorganism to have some selective advantage by overcoming of host defence, thus increasing the invasiveness of the bacteria. Determination of these properties make it possible to evaluate better the virulence of the facultative-pathogenic microorganisms and can therefore be used for microbiological diagnosis. The method used until now to test these characteristics are very time consuming. For these reason we have employed bioluminescence to determine the number of viable cells. This method is very suitable for this purpose.

Blood Bactericidal Activity↗
PubMed1989

[The modification of phagocytosis by different K1 capsule preparations of Escherichia coli].

The influence of two different types of Escherichia coli K1 capsule preparation on the phagosytosis of an E. coli laboratory strain (LN 28) by polymorphnuclear leucocytes (PMNL) is described. Capsule material of E. coli 0.18 and 0.83 was prepared a) from the culture supernatant and b) from a bacterial pellet fraction. When capsule material from the pellet was added to opsonin, before mixing the laboratory strain with the PMNL, it decreased the rate of phagocytosis, compared with untreated opsonin. The preparation from the supernatant of capsule showed no alteration of phagocytosic rate or capacity. These results are explained by the different chemical compositions of the preparations.

Antigens, Bacterial↗
PubMed1988

[Isolation of group-specific polysaccharide complexes from group B streptococci by phenol-water extraction].

The group specific polysaccharide of Group B streptococci was isolated either by means of phenol-water extraction or by Lancefield extraction procedures. Two groups of rabbits were immunized with these substances to induce polyclonal antibodies. The phenol-water extract induced antisera had a significantly higher titer against B streptococci than against A-, D- and G streptococci in the agglutination reaction. The B-specific titers in rabbits immunized with phenol-water extract were significantly higher than those obtained in the rabbits immunized with Lancefield extract. In counter immunoelectrophoresis, only the antisera prepared by immunization with phenol-water extract reacted with standard antigen from group B streptococci. The serological specificity of the phenol-water extract antigen isolated from B streptococci was confirmed by counterimmunoelectrophoresis. The antigen was a heterologous fraction with a molecular mass of 8 x 10(4)-2 x 10(6) Dalton.

Counterimmunoelectrophoresis↗
PubMed1987

[Use of fermenter dialysis culture technic to grow clinically important bacteria which carry capsules. I. Escherichia coli K1].

For mass culture of Escherichia coli K1 a fermenter dialysis culture technique based on an artificial hollowfiber kidney and substrate feeding is described and compared with conventional shaking culture and fermenter batch culture techniques. Important growth parameters as bacterial dry weight, optical density and live cell counts demonstrate the advantage of this new method. On the basis of bacterial yields, effectivity had increased about 100 fold. The synthesis of K1 capsular polysaccharides, which is influenced by a number of factors, proved to be good. Thus it was possible to obtain the quantities of native capsular substance necessary for bed-side diagnostics and the investigation of this virulence marker.

Antigens, Bacterial↗