Cooper, Louis Z. (New England Medical Center Hospital, Boston, Mass.), Morton A. Madoff, and Louis Weinstein. Heat stability and species range of purified staphylococcal alpha-toxin. J. Bacteriol. 91:1686-1692. 1966.-Heating of high-titer purified staphylococcal alpha-toxin at 60 and 80 C resulted in a double-sloped curve of inactivation of the hemolytic effect on rabbit erythrocytes. Early inactivation was less at the lower temperature, but activity persisted for a longer time at 80 C. Toxin inactivated at 60 C showed renewed activity when heated briefly at 80 C. A precipitate which formed during heating of alpha-toxin at 60 or 80 C yielded hemolytic activity when resuspended and heated at 80 but not at 60 C. Supernatant fluid of heat-precipitated toxin was heat-labile and did not regain activity when heated at 80 C. The results indicate that the "paradoxical effect" of heating of staphylococcal alpha-toxin is not due to a thermolabile inhibitor, but results from alteration of the toxin molecule to a heat-stable active form. Demonstration of renewed activity by 80 C heating of purified toxin requires potent toxin preparations and brief heating periods. Hemolysis of erythrocytes of several animal species by purified alpha-toxin was generally similar to that produced by impure toxin. Rabbit cells were most susceptible. Human and horse erythrocytes hemolyzed to less than 0.1% of the extent of rabbit cells. Blood cells of other species were intermediate in their response to the lytic effect of alpha-toxin.

Animals↗

PubMed1966

Diagnosis and management: congenital rubella.

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Adolescent↗

PubMed1965

Neonatal thrombocytopenic purpura and other manifestations of rubella contracted in utero.

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Bone Diseases↗

PubMedDate not supplied

Inhibition of HIV replication in lymphocyte cultures of virus-positive subjects in the presence of sho-saiko-to, an oriental plant extract.

An oriental remedy, Sho-saiko-to (SST) consisting of a mixture of aqueous extracts from seven different plants and whose most active component is the chemically defined compound baicalein was tested for its ability to inhibit the production of the human immunodeficiency virus (HIV). The testing was done with cultures of human lymphocytes obtained from HIV-positive asymptomatic subjects and patients with ARC or AIDS. The replication of the virus was monitored by quantitative assay of the reverse transcriptase (RT) activity and of the synthesis of antigen p24. The lymphocyte cultures (LC) were maintained in the absence and in the presence of 25, 50 or 100 micrograms/ml of SST, and monitored for up to 5 weeks. The results showed that in LC from asymptomatic subjects RT activity and synthesis of p24 was completely inhibited by low concentrations of SST. High concentrations of SST inhibited virus replication in 80% of LC from ARC patients, but were completely ineffective in LC from AIDS patients. It was observed that the RT activity was more sensitive to inhibition by SST than the synthesis of p24, and that the antiviral effect was dependent on the virus load of the LC.

AIDS-Related Complex↗

PubMedDate not supplied

Rubella.

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Global Health↗

PubMedDate not supplied

Cell-mediated immune response in rubella infections.

Cultures of lymphocytes from rubella-susceptible persons did not respond to stimulation with purified rubella antigen whereas those from persons who had experienced natural infection responded strongly to specific antigenic stimulation. The response of cultures of lymphocytes from vaccinees is weaker than that of naturally infected persons, and it appears that the response of lymphocytes from congenitally infected children depends on their gestational age at the time of interuterine infection. Vaccination or revaccination of immune subjects elicits a fast booster-type cell-mediated immune response. This property is useful for detecting the immune status of women exposed to rubella during pregnancy whose rubella history is unknown and whose humoral immune response is negative.

Adolescent↗

PubMedDate not supplied

Diabetes mellitus and autoimmunity in patients with the congenital rubella syndrome.

An increased incidence of insulin-dependent diabetes mellitus (IDDM) has been reported in patients with congenital rubella syndrome (CRS). Thus, studies of children with CRS would be of great importance in following the development of IDDM in a susceptible population. A total of 242 children with CRS, 30 of whom already have diabetes (mean age, 17.4 +/- 0.3 years) have been evaluated. In this latter group, the frequency of HLA DR3 is significantly increased and that of HLA DR2 significantly decreased. While pancreatic islet cell cytotoxic or surface antibodies (ICSA) are found in 20.2% of the total population of patients with CRS, they are present in 50%-80% of patients with glucose abnormalities. In all but five of the ICSA-positive patients, glucose abnormalities are currently present. In addition, glucose intolerance is found in greater than 50% of the DR3-positive nondiabetic patients with CRS evaluated to date. The data demonstrate that patients with CRS at risk for IDDM have the same genetic and immunologic features seen in classic IDDM, namely the presence of HLA DR3 and the absence of HLA DR2 and the high prevalence of ICSA before decompensation.

Adolescent↗