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Biomedical subjects

M Mehl

Publications and source records attributed to M Mehl.

At least 37 records · Page 2Linked to original sources
PubMed1989

[A method for the standardized in vitro testing of biomaterials with bacterial cultures].

The preclinical investigation of potential biomaterials requires a comprehensive profile of biological parameters. In the present paper a new in vitro test will be described which allows a standardized testing of the effect of biomaterials on the proliferation of bacteria. For this test eluates of solid materials, granulates or powders of potential biomaterials were prepared. These eluates were mixed a bacterial culture containing a definite number of microbes and incubated for 4-20 hours at 37 degrees C. The effect on bacterial growth was determined photometrically.

Biocompatible Materials↗
PubMed1989

Cryopreservation of newly formed human and mouse hybridoma cells.

The aim of this study was to develop an optimal technique for cryopreservation of newly formed human and mouse hybridoma cells immediately after fusion. It was shown that human hybridoma cells could be frozen most successfully at a cooling rate of 5 K/min whereas mouse hybridomas at 1 K/min. The percentage of FCS in cryopreservation media (30 or 90%) had no influence on the recovery of both types of hybridomas. For testing the efficiency of freezing, the fusion rate (number of growing and Ig producing hybridomas), the ratio of IgM:IgG-producing initial hybridoma lines and yields of specific wells were analysed. Comparable results were registered when optimally cryopreserved and non-frozen material was studied. Optimization of the cryopreservation of newly formed hybridomas may be of methodological importance, especially when a time-consuming screening for antigenic specificities must be carried out.

Animals↗
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↗
PubMed1984

[Cultural and serologic studies of the colonization of mycoplasmas in hemodialysis and kidney transplant patients].

According to the present investigations the frequency of the proof of mycoplasms in the urine of haemodialysed patients and patients who underwent renal transplant operations does not differ from that of healthy control persons. A routine proof of mycoplasms is not proved necessary for the groups of patients examined. The standardisation of the plasms of urea--of patients with different pictures of a disease--resulted in a dominance of the Serovar III. No relation could be seen between Serovar and haemadsorption ability of the plasms of urea. The haemadsorption rate was significantly higher in isolates of patients than in isolates of healthy persons.

Adolescent↗
PubMedDate not supplied

[Change in sodium and potassium concentration in human seminal plasma infected experimentally with Ureaplasma urealyticum].

The concentration of sodium and potassium ions was measured by flame photometry in human seminal plasma and human sperm cells as well as in a sperm cell suspension infected experimentally with Ureaplasma urealyticum during incubation as long as 22 hours. The sodium concentration is 86.2 +/- 21.97 mmol/l cells in sperm cells and 120.8 +/- 15.87 mM in seminal plasma. The potassium concentration is 33.2 +/- 16.35 mmol/l cells in sperm cells and 26.7 +/- 4.92 mM in seminal plasma. The sodium concentration decreased considerably in the suspension medium of sperm cells during the first hour of incubation and increased again subsequently. The potassium concentration in the suspension medium changed only little. The sodium concentration in the infected sperm cell suspension was insignificantly increased compared with the mycoplasma-free controls. The potassium concentration was slightly higher in the infected specimens than in the controls. There was no mycoplasma-induced effect on the concentration of sodium and potassium in the sperm suspension after experimental infection.

Humans↗