Search PubMed⌕ Search

Biomedical subjects

R M Chanock

Publications and source records attributed to R M Chanock.

393 records · Page 22Linked to original sources
PubMed1965

Hemolysin of Mycoplasma pneumoniae: tentative identification as a peroxide.

Mycoplasma pneumoniae produces a soluble hemolysin active against guinea pig erythrocytes. This hemolysin appears to be a peroxide, since catalase or peroxidase inhibits its activity. The action of catalase and peroxidase is specific, since heating the enzymes abolishes their effect on the hemolysin. In addition, 3-amino- 1,2,4-triazole, a potent inhibitor of catalase, reverses the inhibitory effect of the enzyme. The hemolysin of M. laidlawii is also a peroxide. The hemolysins of M. pneumoniae and M. laidlawii seem unique for microbial organisms since the bacterial hemolysins which have been described have been protein or lipid in nature.

Animals↗
PubMed1965

Relationship of Mycoplasma pneumoniae to other human Mycoplasma species studied by gel diffusion.

Taylor-Robinson, David (National Institute of Allergy and Infectious Diseases, Bethesda, Md.), Otakar Sobeslavský, and Robert M. Chanock. Relationship of Mycoplasma pneumoniae to other human Mycoplasma species studied by gel diffusion. J. Bacteriol. 90:1432-1437. 1965.-Conditions are presented for the production of four lines of precipitate between Mycoplasma pneumoniae antigen and homologous hyperimmune rabbit serum in double diffusion in agar. The specificity of the reaction was shown by the fact that M. pneumoniae antigen did not react with antisera to the other human mycoplasma species, nor did M. pneumoniae antiserum produce lines with antigens prepared from the other human mycoplasmas. In addition, there was no reduction in the number or intensity of precipitation lines after absorption of M. pneumoniae antiserum with heterotypic mycoplasma antigens, or after absorption of heterotypic mycoplasma antisera with M. pneumoniae antigen. These findings indicate that, of the human mycoplasma species so far studied, M. pneumoniae is antigenically the most distinct.

Animals↗
PubMedDate not supplied

What biotechnology has to offer vaccine development.

New developments in biotechnology have led to a number of new approaches for the development of vaccines aimed at preventing infectious disease. This report summarizes some of the principles underlying these new technologies and illustrates some applications of these technologies to practical vaccine development.

Biotechnology↗
PubMedDate not supplied

Prospects for development of a rotavirus vaccine against rotavirus diarrhea in infants and young children.

Major advances have been made in elucidating the etiologic agents of severe infantile diarrhea, and it is clear that rotaviruses are the single most important etiologic agents. Progress in the development of rotavirus vaccine candidates has also moved swiftly with the "Jennerian" approach, in which a related live, attenuated rotavirus strain from a nonhuman host is used as the immunizing antigen. If this strategy is not effective against all rotavirus serotypes, reassortant rotaviruses hold great promise for the development of a multivalent vaccine. Field trials with the "Jennerian" approach vaccines are under way, and phase 1 trials with the reassortants have been initiated.

Animals↗
PubMedDate not supplied

Use of temperature-sensitive and cold-adapted mutant viruses in immunoprophylaxis of acute respiratory tract disease.

Efforts currently are underway to develop mutations in the influenza A viral genome that will bring about a satisfactory level of attenuation and that can be identified by simple in vitro techniques. Two types of donor viruses that bear such mutations are being evaluated. One donor virus possesses temperature-sensitive (ts) mutations on the P1 and P3 genes, while the other donor bears both ts and cold-adaptation (ca) mutations. The mutant genes from these donors were transferred by gene reassortment to recombinant viruses bearing the surface antigens of new epidemic or pandemic viruses, and in every instance a satisfactory level of attenuation was achieved. However, genetic instability remains a formidable problem. Temperature-sensitive mutants of respiratory syncytial virus also have been evaluated for their usefulness in immunoprophylaxis of respiratory tract disease. Although the desired mutant has not been identified, some progress has been made.

Acute Disease↗
PubMedDate not supplied

Approaches to immunization of infants and young children against gastroenteritis due to rotaviruses.

Recent studies have shown that in developed countries rotaviruses are the single most important etiologic agents of acute gastroenteritis that requires hospitalization of infants and young children. Although deaths from gastroenteritis are, in general, infrequent in the developed countries, an effective rotavirus vaccine would clearly be of benefit to reduce the heavy toll of morbidity from gastroenteritis due to rotavirus. In the developing countries the impact of diarrheal diseases is staggering. It was recently estimated that in Asia, Africa, and Latin-America during a one-year period there would be 3.5 billion cases of diarrhea and 5-10 million deaths associated with diarrhea; in addition, diarrhea was ranked first in freqency in the categories of disease and mortality. In the developing countries rotaviruses are known to cause diarrhea, but their relative role in this high mortality rate is not yet known. epidemiologic data indicate that development of an effective rotavirus vaccine would reduce morbidity, and they suggest that a vaccine would also reduce a portion of the mortality from diarrheal disease. The prospects and approaches for the development of an effective rotavirus vaccine are presented. The recent successful propagation of rotavirus type 2 in cell culture represents an important step in this regard. In addition, the antigenic relation between human and animal strains offers another possible approach. The need for a live attenuated vaccine is indicated by the prime role played by local intestinal immunity in resistance to rotavirus disease.

Animals↗
PubMedDate not supplied

New opportunities for development of safe, effective live virus vaccines.

Effective vaccines are not available for most viral diseases. This situation may soon change when the full force of contemporary molecular biology is applied to immunoprophylaxis. In certain viral diseases, particularly those affecting the respiratory and gastrointestinal tracts, live attenuated vaccines are needed to confer effective protection. Until now the major obstacle to success has been genetic instability. It may be possible to construct stable, satisfactorily attenuated mutants by cloning viral DNA or RNA and then subjecting the cloned DNA to enzyme surgery to create viable deletion mutations. Modified cloned DNA derived from positive-strand viral RNA could then be transferred back into its virus by transfection of cells. Conversion of mutant cloned DNA into negative-strand RNA and transfer into its virus will require a more elaborate type of rescue.

Adenoviruses, Human↗