Effect of pH on sporicidal and microbicidal activity of buffered mixtures of alcohol and sodium hypochlorite.

The effect of pH on the activity of buffered sodium hypochlorite solution, and a buffered methanol/sodium hypochlorite mixture, against Bacillus subtilis spores was investigated. The best results, considering both sporicidal activity and stability, were achieved in the pH range 7.6--8.1. The sporicidal activity and stability of five alcohol/hypochlorite mixtures, each containing a different alcohol and buffered to pH 7.6 and of hypochlorite alone buffered to pH 7.6, were compared. The mixtures were marginally more sporicidal than hypochlorite alone when fresh but were much less stable. An unbuffered methanol/hypochlorite mixture, a methanol/hypochlorite mixture buffered to pH 7.6, and hypochlorite alond buffered to pH 7.6 were all found to be effective against six vegetative organisms and spores of B. subtilis and Clostridium sporogenes. By buffering alcohol/hypochlorite mixtures or hypochlorite solution alone in the pH range 7.6--8.1, high sporicidal activity can be achieved with low concentrations of alcohol and hypochlorite. Such formulations show promise for the disinfection of heat-sensitive medical equipment.     

A comparison of microaerobic systems for the culture ofCampylobacter jejuni andCampylobacter coli

The relative ability of two commercial gas generating envelopes, the evacuation-replacement technique, and a candle jar, to produce a satisfactory microaerobic atmosphere for the culture of 45Campylobacter strains on non-selective medium and five selective media (Skirrow's, modified Butzler's, Blaser's, Campy-BAP and Preston medium) was investigated quantitatively. A candle jar, and modified Butzler's medium proved to be of limited use. The ability of four commercial gas generating envelopes to produce a satisfactory microaerobic atmosphere in four anaerobic jars of different volume was investigated using five referenceCampylobacter strains. Not all of the combinations worked. The oxygen and carbon dioxide concentrations produced in the microaerobic systems studied were measured with gas analysers. The evacuation-replacement technique produced far less variable concentrations of oxygen and carbon dioxide than did the envelopes.     

Identification of Mycobacterium tuberculosis antigens in Seibert fractions by immunoblotting.

Seibert fractions prepared from Mycobacterium tuberculosis culture filtrates were evaluated by immunoblotting with a serum pool from patients with active pulmonary tuberculosis. Antibody activity was observed primarily with antigens in the polysaccharide II and A protein fractions; these fractions were further evaluated by immunoblotting with sera from individual patients with tuberculosis, from individuals without tuberculosis and positive for the purified protein derivative antigen skin test, and from individuals negative for the purified protein derivative antigen skin test. The antigens identified in the protein A fraction, a 32,000-molecular-weight antigen and a heterogeneous high-molecular-weight antigen, reacted with antibody found in sera from all patients with tuberculosis and with antibody from over 25% of the control individuals. A 10,000-molecular-weight antigen, a 30,000- to 44,000-molecular-weight antigen, and a heterogeneous high-molecular-weight antigen were observed in the polysaccharide II fraction; these antigens reacted with serum antibody from 70% or more of the patients with tuberculosis and with antibody from 20 to 70% of the control individuals. One of the antigens, with a molecular weight ranging from 17,000 to 28,000 in the polysaccharide II fraction, reacted with antibody in 64% of the sera from patients with tuberculosis but with only 1 of 15 control normal sera. This antigen may elicit an antibody response specifically associated with tuberculosis.     

Blood-free selective medium for isolation of Campylobacter jejuni from feces

A blood-free selective agar is described which contains charcoal, ferrous sulfate, sodium pyruvate, casein hydrolysates, cefazolin, and sodium deoxycholate (CCD agar). CCD agar was compared with Preston medium for isolation of Campylobacter jejuni from human feces, and isolation rates were similar on both media, but CCD agar was less selective. Temperature studies at 37 and 42 degrees C confirmed that incubation of direct plates at 42 degrees C for 48 h was necessary for maximum isolation of C. jejuni.     

Routine HLA-B27 typing by flow cytometry: differentiation of the products of HLA-B*2702, B*2705 and B*2708

Patient HLA-B27 typing is widely performed as an aid to the diagnosis of several diseases, particularly ankylosing spondylitis. Typing by flow cytometry, using monoclonal antibodies, has been shown to be a potentially useful alternative to classical serology on account of its speed, simplicity and economy. However, we required a flow cytometry typing procedure that would accurately differentiate HLA-B27 (Bw4) from B2708 (Bw6) and not be confounded by other HLA-B7/B27 cross-reactive group antigens. Accordingly, we evaluated the simultaneous use of two monoclonal antibody preparations, ABC-m3-FITC (anti-B27 + weak B7)/BB7.1-PE (anti-B7) and FD705-FITC (anti-B27), by testing a highly selected panel of 62 reference lymphocytes containing examples of all HLA-B7/B27 cross-reactive group antigens, including: HLA-B42, B47, B48, B73, B703, B2702, B2705 and B2708. In addition, 268 whole blood samples from routine patient requests for B27-associated disease typing were tested in parallel with HLA-B typing using the standard complement-dependent microlymphocytoxicity test. The detailed specificity of the three monoclonal antibodies was established and the products of HLA-B*2702, B*2705 and B*2708 were found to be readily differentiated from each other and all other HLA-B7/B27 cross-reactive HLA-B antigens.     

Social support, AIDS-related symptoms, and depression among gay men.

This study examined the impact of social support and HIV-related conditions on depression among 508 gay men participating in the San Francisco Men's Health Study, a population-based prospective study of single men aged 25-54 years. The number of HIV-related symptoms experienced significantly predicted depression cross-sectionally and 1 year later. Satisfaction with each of three types of social support (emotional, practical, informational) was inversely correlated with depression. Men who were more satisfied with the social support they received were less likely to show increased depression 1 year later. Degree of satisfaction with informational support appeared especially critical in buffering the stress associated with experiencing HIV symptoms. These findings offer valuable insight in understanding the psychological needs of gay men confronting the AIDS crisis and have important practical implications for designing mental health services to meet those needs.