Biomedical subjects
Publications and source records attributed to W Köhler.
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Regarding of microbiological aspects of arthritis three forms of joint diseases are under investigation: the septic arthritis, the reactive arthritis and the Rheumatoid Arthritis. In 95% of patients with septic arthritis microorganisms as causative agents responsible for the disease are described: Staphylococci, Streptococci, some gram-negative bacteria. By an haematogenic route of infection predominantly patients with immunosuppressive therapy are altered. In newborns and children septic arthritis is to observe more rarely. A reactive arthritis is a postinfectious sterile process in dependence on an infection occurred at an earlier time. As etiologic agents Yersinia, Enterobacteriaceae and Campylobacter have been discovered. 80% of the patients suffering such a reactive arthritis are carrier of the HLA-B27 system. The etiology of the Rheumatoid Arthritis is an open, unanswered problem. Of importance are: immunogenetic conditions, autoimmune phenomena, endocrinologic, dietetic and psychologic factors as well as bacteria and viruses as causative agents: cocci, bacilli, Diphteroids, endoparasitic bacteria (Listeria, L-forms, Mycoplasma, Chlamydiae), viruses (Adeno-, Mumps-, Measles-, ECHO-, Coxsackie-A- and B-, Hepatitis-, Cytomegalo-, Para-influenza-, Retro-, Parvo- and Rubella viruses). In the last years the EBV is of interest covering the question of a distinct virus persistence in tissues and the adequate limiting factors. Perhaps a defect of the hu-IFN-gamma-system might be of immunopathological and clinical significance.
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Visual evoked potentials (VEPs) to flash stimuli were recorded twice from 26 children aged 10-13 years, with an intersession interval of about 10 months. Test-retest reliability was poor for recordings taken from scalp locations overlying non-specific cortex and somewhat better for specific cortex. The size of consistency coefficients (i.e. correlations within session) showed that noise and artefacts were not the decisive factors which lower reliability. A comparison with retest correlations of broad band parameters of the EEG at rest for the same sample showed, to our surprise, smaller retest reliability for VEP parameters. Variability of the VEP in children over time seems to be a substantial as its well-known inter-individual variability.
Reference strains of Streptococcus pyogenes and strains from recent epidemics and sporadic cases of scarlet fever were examined for their ability to produce erythrogenic toxin type A (ET A) by ELISA and double immunodiffusion (Ouchterlony) using an anti-ET A antibody purified by affinity chromatography. Of the reference strains (most of them isolated before 1945) 16/51 produced more or less ET A (Table 1). ET A synthesis is strain-specific, but not type-specific. Well-known toxin producers like the strains NY-5; 594 or "Smith" produce up to 16.000 micrograms/l under optimal culture conditions. Type 3 strains isolated from scarlet fever patients during the outbreak 1972/73 seem to belong to one clone as evidenced by the uniform SDS-PAGE pattern: They were found to produce 5-200 micrograms/l (mean 68 micrograms/l) ET A only. Type 3 strains from sporadic cases, isolated 10 years later, produced 0-138 micrograms/l (mean 30 micrograms/l). Strains of the type 1 clone, causing the epidemic in 1982/83 produced only 0.75-10 micrograms/l (mean 8 micrograms/l) ET A (Table 3). Only a few strains of S. pyogenes isolated 1984 or later synthesized ET A but they were found more often to produce ET B (proteinase precursor) in batch cultures. S. pyogenes strains seem to have lost their ability to produce large amounts of ET A during the last decades. Because this toxin must be considered as a pathogenicity factor the decrease in toxin production may be one reason for the present mild form of scarlet fever.
Group A streptococcal reference strains of various M-types as well as three clinical isolates, and clinical isolates of group B, C and G streptococci were compared with respect to their agglutination by fibrinogen, specific binding of monovalent fibrinogen fragment D, and their hydrophobicity measured by salt aggregation in ammonium sulfate dilutions (SAT). Fibrinogen fragment D binding to M positive group A streptococci and clinical isolates of group A reduced salt aggregation of these strains from 0.06 molar to 2 molar in the ammonium sulfate dilution series. Group A, M protein negative and group B, C and G control strains used aggregated only at high ammonium sulfate concentration (2 molar) or not at all. Treatment of these strains with fibrinogen fragments did not influence their weak salt aggregation. By elution of specific retained fragment D from the type 1 M positive strain 40/58II by treatment of cells with 0.1 molar citric acid, 6 molar urea, buffer, pH 3.0, surface hydrophobicity could partially be restored (SAT titer 0.5 molar). Treatment of streptococcal cells with fibronectin or albumin at much higher protein concentrations had a moderate effect on surface hydrophobicity. These results indicate that binding of fibrinogen fragment D to the receptor can block a hydrophobic surface domain of the receptor or induce a sterical hindrance affecting surface exposure of associated surface molecules. A fibrinogen receptor-also responsible for binding of fibrinogen fragment D-is in M positive group A streptococci covalently linked to M protein. Decrease of salt aggregation tendency after mild pepsin treatment to release M protein supported these findings.
The gene of Streptococcus pyogenes erythrogenic toxin type A (speA) has been previously cloned in Streptococcus sanguis (Challis) and produces extracellular erythrogenic toxin type A (ET A). The ET A produced and secreted by this heterologous host was purified to homogeneity and shown to have properties identical to ET A produced by S. pyogenes strain NY-5; i.e., serological identity in immunodiffusion, migration in SDS-polyacrylamide gel electrophoresis, mitogenic activity, inhibition of mitogenic activity by specific antibody, and precipitation by an international scarlatina antitoxin preparation. The cloned speA gene specified an ET A which had a molecular weight identical to that of ET A from S. pyogenes previously reported from this laboratory. NH2-terminal sequence determination of the purified protein showed the first nine residues to be gln gln asp pro asp pro ser gln leu; this is consistent with predictions made from the nucleotide sequence of the speA gene according to Weeks and Ferretti and different from the sequence published by Johnson et al.
Receptors for erythrogenic toxin A (ETA) of Streptococcus pyogenes (strain NY-5) were demonstrated on human peripheral blood lymphocytes by binding of ETA-gold conjugates to the cell surface. The specificity of the binding was proved in control experiments. The dark-red granules observed by light microscopy on unfixed cells were revealed by transmission electron microscopy to be patches of gold particles. By light microscopy on samples from 48 blood donors a mean value of 34 +/- 13% of ETA-receptor bearing lymphocytes was ascertained. The predominant part of the cells exhibited only a weak or moderate labelling. Transmission electron microscopy of prefixed cells revealed an attachment of single gold particles distributed over the whole cell surface. Counts of gold particles on serial sections yielded depending on prefixation values of 50-600 receptors/cell (1% glutaraldehyde) and 1000-7000 receptors/cell (0.26% glutaraldehyde), respectively. ETA cloned in Streptococcus sanguis as well as the toxoid of ETA exhibited a comparable binding as ETA (NY-5).
Human isolates of groups A, C and G streptococci as well as animal isolates of group C were investigated with respect to their binding capacity for human IgG by using the direct fluorescence technique and the Mancini test. From each serological group of human isolates, more than 100 strains were tested. The results were evaluated statistically with respect to serological group, type and source of isolates. Between human isolates of groups A, C and G, no statistical differences concerning IgG binding were found. However, group C streptococci isolated from pigs showed a significantly higher number of strains with high IgG binding than the human isolates of groups A, C and G. Group A streptococci isolated from suppurating lesions showed an increased IgG uptake when compared with isolates from scarlet fever patients or patients with throat infections. However, strong IgG binding by group A streptococci seems not to be restricted to certain types. By using selected streptococcal strains, it was found that IgG absorption from a solution of purified IgG was much higher than from IgG solutions containing albumin or from diluted serum. The results are discussed in connection with the competition of different plasma proteins for binding sites on the streptococcal cell surface and with a possible influence of IgG receptors on the virulence of streptococci.
Three different enzymatic extraction procedures were tested for their effectivity in releasing IgG-binding peptides from the streptococcal cell wall. Streptococcus equisimilis strain 12628 isolated from pig was incubated with phage-associated lysin, trypsin and Streptomyces globisporus lytic enzyme and the extracts were investigated by Western blotting, indirect erythrocyte agglutination and Ouchterlony diffusion for IgG-binding activity. With all treatments IgG-binding peptides were extracted. However, no homogenous IgG-binding material was released by the enzymes tested. In each case a multiple peptide pattern with IgG-binding activity was found. The molecular weights of the active peptides released also differed between the extraction procedures. The isoelectric points between 4.0 and 4.3 of IgG-binding components were found to be similar for all three extracts.
Variability of single visual evoked potentials was investigated by means of three statistical tests sensitive to amplitude variations, gradual changes, and latency jitter, respectively. In a sample of (n = 78) normal children, a considerable number of inhomogeneous responders was found, and most prominent were gradual potential changes and latency jitter. Removal of latency jitter demonstrated that the gradual changes are not of latency type and only partly of the amplitude type. As found from empirical densities, there is strong indication that there were subpopulations differing in their response style. On the whole, however, it was concluded that there was no clear, interindividually stable type of response variation in these data.
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Spontaneous cochlear emissions can vary on a daily basis and are subject to frequency shifts in the range of some thousand parts. A correlation of the shiftings on the right versus those on the left ear is significant in two cases, thus pointing to a common origin.
Binaural beats were studied before and during a situation of temporary threshold shift, and no frequency shift could be found. In contrast, subjective binaural frequency comparison revealed a distinct shift. These findings demonstrate the two known modes of perception.