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Biomedical subjects

R Austrian

Publications and source records attributed to R Austrian.

At least 91 records · Page 5Linked to original sources
PubMed1968

Mutation in pneumococcus type 3 affecting multiple cistrons concerned with the synthesis of capsular polysaccharide.

The genetic behavior in transformation reactions of 20 noncapsulated mutants of pneumococcus type III suggests that each has a single-site mutation in the locus controlling the synthesis of uridine diphosphate glucose (UDPG) dehydrogenase. Each strain is capable of yielding transformants of the binary capsular type SI-III when exposed to deoxyribonucleic acid (DNA) from type I cells. One additional mutant reacted differently and behaved as if it were a multisite mutant with the mutation affecting both the locus for UDPG dehydrogenase and that controlling the synthesis of high molecular weight type III capsular polysaccharide. When exposed to DNA from type I pneumococci, this strain yielded transformants which were genotypically binary but which expressed only the type I capsular phenotype.

DNA, Bacterial↗
PubMed1967

Qualitative differences in the behavior of pneumoncoccal deoxyribonucleic acids transforming to the same capsular type.

A method is described for estimating quantitatively the frequency of transformation of pneumococci to new capsular types. It is found that, when S-(III) cells are exposed to deoxyribonucleic acid (DNA) from wild-type I strains, transformation to SI occurs at a frequency 20 to 60 times that of transformation to the binary type SI-III. SI markers on DNA isolated from binary strains behave qualitatively and quantitatively in a different manner from the same markers on DNA from wild-type I strains and will transform S-(III) cells only to SI-III. Strains are described which produce only one capsular polysaccharide, but which are genetically binary and carry a second capsular genome with a mutated gene so that the second polysaccharide is not produced. Stability and other characteristics of binary strains are discussed, and one hypothesis for the genetic organization of binary strains is presented.

Chromosome Mapping↗
PubMed1966

Transformation of pneumococcal M protein.

Feingold, David S. (The University of Pennsylvania School of Medicine, Philadelphia), and Robert Austrian. Transformation of pneumococcal M protein. J. Bacteriol. 92:952-955. 1966.-Antisera prepared with vaccines of noncapsulated pneumococci of a given M protein type and absorbed with organisms of heterologous M protein type agglutinated specifically the homologous organisms. Specific anti-M protein sera can be used as selective reagents to permit isolation of organisms of heterologous M protein type from mixed populations. This capacity of anti-M protein sera was employed to facilitate recovery of intraspecific M protein transformants of pneumococcus. Attempted interspecific transfer of group A beta-hemolytic streptococcal M protein to pneumococcus by means of transformation reactions, however, was not accomplished.

Agglutination↗
PubMed1966

Importance of carbon dioxide in the isolation of pneumococci.

Austrian, Robert (The University of Pennsylvania School of Medicine, Philadelphia), and Patricia Collins. Importance of carbon dioxide in the isolation of pneumococci. J. Bacteriol. 92:1281-1284. 1966.-Of the strains of pneumococci isolated from man, 8% manifest a requirement for CO(2) if detectable growth is to occur on the surface of solid media. The pneumococci most frequently manifesting this requirement are types I, III, XVI, XXVIII, and XXXIII. These strains will grow in the presence or absence of oxygen provided the atmosphere in which they are incubated contains CO(2). Review of published data provides no unequivocal evidence for the existence of anaerobic pneumococci.

Carbon Dioxide↗
PubMedDate not supplied

Immunization of elderly people with polyvalent pneumococcal vaccine.

On March 28-30, 1988 the World Health Organization held a "Consultation on Immunization of Elderly People with Polyvalent Pneumococcal Vaccine". The meeting was held in Copenhagen and was sponsored by the WHO Regional Office for Europe and its Health of the Elderly programme. The meeting was attended by 18 temporary advisors and three observers. One of the main conclusions of the meeting was that pneumococcal vaccination should be recommended for all elderly persons and for all persons at high risk of acquiring pneumococcal infection, regardless of age.

Aged↗
PubMedDate not supplied

Pneumococcal polysaccharide vaccines.

Pneumococcal infections are major causes of morbidity and mortality in children throughout the world. For this reason and because of the increasingly frequent isolation of multiply resistant pneumococci of the serotypes most often causing infection in childhood, prophylactic immunization offers the best prospect of reducing the incidence of such infections in the future. Studies of the immune system of humans have shown that immunologic maturation continues throughout the first decade of life and that responsiveness to some purified bacterial polysaccharides may be delayed until several years after birth. Vaccines of such capsular polysaccharides conjugated chemically to protein have been found to be immunogenic at an earlier age and to stimulate the development of IgM and IgG antibodies and of "immunologic memory." Current investigations suggest that administration of polyvalent vaccines of polysaccharide-protein conjugates in infancy followed by the administration of vaccines of purified polysaccharides after the age of 10 years offers the prospect of reducing significantly the incidence of pneumococcal infections.

Bacterial Vaccines↗
PubMedDate not supplied

Pneumococcus: the first one hundred years.

Some of the major contributions to biology and medicine resulting from studies of the pneumococcus (Streptococcus pneumoniae) and of the diseases caused by it in the century following its initial isolation are reviewed briefly. Among the topics considered are cellular and humoral defenses against pneumococcal infection, the role of pneumococcus in the development of quantitative immunochemistry, the historical position of the pneumococcus in the recognition of bacterial resistance to drugs, and the fundamental role played by this organism in the origins of molecular genetics and molecular biology. Because of the vast store of knowledge of the pneumococcus that has been acquired in the past 100 years, the hope is expressed that this knowledge will continue to grow and to serve as a basis for the extension of understanding both the bacterial cells and of the processes of infection.

Animals↗
PubMedDate not supplied

Some observations on the pneumococcus and on the current status of pneumococcal disease and its prevention.

Although the means whereby pneumococcus damages the hosts it invades remain unknown, some advances in understanding the biology of this organism and the pathogenesis of pneumococcal infection have been made in recent years. Knowledge of the composition of the cell wall (C) polysaccharide of the pneumococcus and its relation to the capsular polysaccharides of this organism is considered and a hypothesis of the evolution of the pneumococcal capsule is entertained. Refinements in understanding the pathogenesis of pneumococcal pneumonia, bacteremia, and otitis media are reviewed, and current knowledge of the epidemiology of pneumococcal infections and of the distribution of pneumococcal types causing such infections is discussed. The history of the development of pneumococcal vaccines is summarized briefly, together with an account of the field trials of contemporary polyvalent vaccines of pneumococcal capsular polysaccharides conducted recently.

Antigens, Bacterial↗
PubMedDate not supplied

Antibiotic-resistant pneumococcal disease in children at Baragwanath Hospital, Johannesburg.

Seventeen of 60 cases of pneumococcal bacteremia in children at Baragwanath Hospital in 1983 were caused by strains not fully susceptible to penicillin G. Eight strains had minimal inhibitory concentrations of greater than 1 microgram/ml and five were resistant to four or more antimicrobial agents. Only three isolates were resistant to chloramphenicol. Antibiotic-resistant strains occurred in younger children with a mean age of 13.1 months compared with a mean age of 31.6 months in children with susceptible strains (P less than 0.01). Underlying conditions, including nutritional status, did not correlate with antibiotic resistance of isolates from blood. Some of the resistant strains were apparently community-acquired. Of 3379 nasopharyngeal swabs taken from hospitalized children 829 yielded pneumococci and 408 of these carrier strains were either relatively or fully resistant to penicillin while 241 were resistant to four or more antibiotics. Multiply resistant strains from patients and carriers belonged to serovars 6A, 6B and 19A.

Carrier State↗
PubMedDate not supplied

[Serotypes of Streptococcus pneumoniae isolated from cerebrospinal fluid in 1977-1988 in São Paulo City, Brazil].

Since 1977, the Instituto Adolfo Lutz (IAL) is having interest in the serotyping of S. pneumoniae or pneumococcus from infections caused by this bacteria. The isolated strains have been sent to the WHO Pneumococcal Reference Center, Pennsylvania, U.S.A.. From 1977 to 1988, 1.000 pneumococcus strains isolated from cerebrospinal fluid were typed, according to Danish nomenclature, and 60 serotypes were identified. The most frequent serotypes were 1, 6B, 18C, 14, 5, 3, 6A, 23F, 19F, and 38. Among different age groups, they showed a variable incidence, with serotype 6B in the ages of zero to almost 2 years old, serotype 1 in the age group of 2 to 50 years old, and serotype 3 in the ages over 50. During the 12 years study, 25 serotypes showed some uniformity in the frequency, the same as with the seasonal fluctuations. Concerning the severity of the pneumococcal infections, chiefly meningitis, and the few information related to pneumococcus serotypes which occur in the area, it was considered of high relevance to have the information of serotypes, once polysaccharide vaccines have been employed with success to prevent these infections.

Adolescent↗