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Biomedical subjects

J Rotta

Publications and source records attributed to J Rotta.

At least 37 records · Page 2Linked to original sources
PubMed1979

Biological activity of synthetic subunits of streptococcus peptidoglycan. I. Pyrogenic and thrombocytolytic activity.

The ability of some synthetically prepared analogues of Streptococcus peptidoglycan subunits (dipeptide, tetrapeptide, glycodipeptide and glycotetrapeptide) to cause fever in rabbits and lysis of rabbit blood platelets was studied. While di- and tetrapeptides did not exhibit these activities, glycodipeptides and glycotetrapeptides displayed pyrogenic and thrombocytolytic activities comparable with those of natural peptidoglycans.

Blood Platelets↗
PubMed1979

Prospective study on streptococcal pharyngitis among a town population.

A one-year-round study on pharyngitis incidence among the general population of a town (24,300 inhabitants) was carried out. All patients, with pharyngitis who visited health centres were examined clinically and mcirobiologically. The overall pharyngitis incidence rate and the streptococcal pharyngitis incidence rate were, respectively, 8.3 and 3.9 cases per 100 population. Age-related incidence was highest in the group of 5-10 years, seasonal incidence was highest in autumn. Clinical diagnoses made preliminary to bacteriological examination were correct in only a half of the streptococcal pharyngitis cases. The accuracy of clinical diagnosis of streptococcal pharyngitis could, at best, be raised to 80% if fever of less than or equal to 38.0 degrees C and presence of exudate on tonsils should be considered significant criteria. A great majority of the streptococcal pharyngitis cases were caused by group A streptococci; the prevailing M types were 12, 1 and 3. Emphasis is laid on the necessity of performing microbiological examination of all pharyngitis cases in order to ensure etiological diagnosis and causal therapy. 15)

Adolescent↗
PubMed1978

Serological identification of group A streptococci from throat scrapings before culture.

The use of a microtechnique (modified nitrous acid extraction) to test samples from 150 school children and from patients with acute follicular tonsillitis has indicated that group A streptococci in the throat can be identified from tonsillar scrapings in 30 min. The results are comparable to the grouping results obtained by standard throat culture techniques and the Lancefield procedure for grouping. No cross-reaction with other bacteria or cellular material occurs. Study has also shown that the nitrous acid extraction yields three- to fourfold more polysaccharides than the Lancefield hot-HCl of Fuller formamide techniques. The use of the microtechnique leads to another 20-fold concentration of the antigen. Immune salting-out effect could be obtained with 1.00 M sodium acetate. Such molarity is too low to cause nonspecific slating out. It leads to a strong ampliciation of the precipitin reaction.

Child↗
PubMed1978

Biological characteristics of peptidoglycans of group A streptococcus and some other bacterial species. II. Immunological mechanisms involved in thrombocytolysis.

Immunological mechanisms are involved in the thrombocytolytic activity of peptidoglycan of Group A streptococcus, Streptococcus pneumoniae and Staphylococcus aureus. Inactivation of particular components of complement (heating of blood serum to 56 degrees C,incubation with zymosan or NH4OH) inhibited the thrombocytolytic activity of group A streptococcus peptidoglycan. So did preincubation of Group A streptococcus peptidoglycan with homologous antipeptidoglycan antibody. On the other hand, antibody to Group A streptococcus peptidoglycan did not inhibit the thrombocytolytic effect of Streptococcus pneumoniae or Staphylococcus aureus peptidoglycan. Human platelets are resistant to peptidoglycans. They remain resistant in the presence of rabbit serum although rabbit platelets are highly sensitive to peptidoglycans. This suggests that, for the expression of the thrombocytolytic activity of bacterial peptidoglycan, specific receptors on the surface of platelets must be present in addition to serum factors.

Animals↗
PubMed1977

Biological characteristics of peptidoglycans of group A streptococcus and some other bacterial species. I. Tolerance and effect of antibody in fever response, and heart damaging effect in rabbits.

Induced tolerance to the pyrogenic action of group A streptococcus peptidoglycan decreased after one week and was no longer detectable after the second week. However, one or two further doses of peptidoglycan rapidly restored the tolerance. The passive transfer of plasma from rabbits tolerant to streptococcus peptidoglycan to nontolerant animals failed to transfer tolerance. Antiserum to streptococcus peptidoglycan neutralized the pyrogenic effect of not only streptococcus but also staphylococcus and pneumococcus peptidoglycan; it did not influence the febrile response to endotoxin. Histopathologic changes in the rabbit heart produced by the intravenous injection of staphylococcus or pneumococcus peptidoglycans were similar and were characterized by various stages of degeneration and necrosis. The changes were less pronounced than after streptococcus peptidoglycan. Antiserum to streptococcus peptidoglycan had modest or no counteracting effect on the development of heart alterations after staphylococcus or pneumococcus peptidoglycan.

Animals↗
PubMed1975

Endotoxin-like properties of the peptidoglycan.

Peptidoglycan is responsible for the endotoxin-like properties of the streptococcus cell wall. The pyrogenic response of rabbit to group A streptococcus peptidoglycan prepared by hot formamide or TCA is dose-dependent and is increased if the material is ultrasonically solubilized. The pyrogenicity can be eliminated by the antiserum to the peptidoglycan or by the degradation of the material by lysozyme. Peptidoglycans prepared from cell walls of group B and L streptococci, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pneumoniae produce fever effects comparable to the response after group A streptococcus peptidoglycan. Spirillum serpens and Escherichia coli contain in addition to endotoxin the peptidoglycan which is also pyrogenic. Repeated injections of bacterial peptidoglycan to rabbit result in tolerance to the fever effect. Cross-tolerance was recorded only exceptionally. Rabbits tolerant to endotoxin respond with a lower fever to S. aureus and group A streptococcus peptidoglycans. Intravenous administration of peptidoglycan to rabbit causes extensive alterations in the heart characterized by various stages of the degenerative and necrotic process. Local Shwartzman reaction can be elicited in rabbit by peptidoglycan used either as a preparative or as a provocative dose in combination with endotoxin, or it can be used for both doses. The results obtained with peptidoglycans prepared from various bacteria are fully comparable. Non-specific resistance of mice to infection induced by streptococcus cell walls was found to be dependent on the peptidoglycan activity; cell wall proteins and polysaccharide are inactive. These properties of peptidoglycan resemble those known from endotoxin studies. The data presented suggest the role of peptidoglycan in pathological reactions resulting from host-parasite interaction.

Animals↗
PubMed1975

The thrombocytolytic activity of bacterial peptidoglycans.

The peptidoglycan of group A Streptococcus prepared by hot formamide or TCA extraction has an expressive ability to lyse rabbit blood platelets in vitro. Initial changes in the ultrastructure of platelets can be observed after 10 minutes incubation of rabbit platelets with 0.1 mug of Streptococcus peptidoglycan per ml. The submicroscopic alterations are characterized by changes of the shape and damage of the limiting membrane of the platelets. Larger amounts of peptidoglycan (10 mug/ml and more) cause total destruction of platelets; only remainders of the limiting membrane and free granulomers can be seen. Peptidoglycans of Streptococcus pneumoniae and Staphylococcus aureus exhibit a comparable effect on rabbit platelets. There are substantial differences in the sensitivity of blood platelets of different animal species to the streptococcal peptidoglycan. Rat platelets exhibit a similar thrombocytolytic effect after the Streptococcus peptidoglycan treatment as rabbit ones; however, the development of comparable changes in their submicroscopic structure needs a dose of peptidoglycan 10(2)-10(3) times higher. Platelets of guinea-pig, dog, cat, calf and human appear to be quite resistant under analogous conditions to as such a high dose of Streptococcus peptidoglycan as 500 mug/ml.

Animals↗