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Biomedical subjects

K H Mayer

Publications and source records attributed to K H Mayer.

At least 109 records · Page 6Linked to original sources
PubMed1990

Use of drugs and alcohol by homosexually active men in relation to sexual practices.

The use of alcohol and recreational drugs in relationship to sexual practices was investigated longitudinally and cross-sectionally in a cohort of homosexually active men at a Boston community health center. Use of marijuana, nitrite inhalants, and cocaine decreased by approximately 25-48% during 42 months of follow-up, whereas use of alcohol showed little change. Men who initially reported both high-risk sexual practices and some use of alcohol or marijuana and who subsequently stopped using marijuana or reduced their frequency of alcohol use were significantly more likely to stop those unsafe sexual practices than were those who continued to use these substances. Men who at their most recent visit reported impaired judgement during sexual activity due to substance use, and particularly due to drug use, had significantly higher levels of perceived susceptibility to AIDS and barriers to behavior change, and lower levels of self-efficacy, which were independent of their unsafe sexual practices.

Acquired Immunodeficiency Syndrome↗
PubMed1990

[Occupational disability evaluation: comparison of subjective assessment with an objective point system].

Our assessments of working disability in 83 expertize on silicosis suffers were subsequently compared with a computer-aided scoring system. In 57% of the cases, full agreement was found; in 14% our estimates were higher and in 20% lower than the computer-aided scores. We investigated the reasons for the discrepancies, and attempted an assessment of computer-aided establishment of medical expertize.

Austria↗
PubMed1989

Duration of human immunodeficiency virus infection before detection of antibody.

To estimate the duration and frequency of the period of HIV infection without detectable antibody, modelling techniques were applied to results of detection of HIV DNA by means of the polymerase chain reaction (PCR) and to data from cases in published reports. PCR was carried out with gag and env region primers on samples from 27 homosexual and 12 haemophilic men for whom stored samples were available from before and after seroconversion; serum was also tested for p24 antigen by antigen-capture enzyme immunoassay. HIV DNA was detectable before seroconversion in 4 men; in all 4 PCR was positive only in the seronegative sample taken closest to the time of seroconversion. In 3 men antigen was detected before seroconversion; in each case HIV DNA was also detected. By a Markov model, the time from infection with HIV (as assessed by detection of HIV DNA) to first detection of HIV antibody was estimated to be 2.4 (SE 2.1) months for the median individual. Modelling of cases of HIV infection with known exposure in published reports gave a median estimate of 2.1 (0.1) months from exposure to antibody detection, and 95% of cases would be expected to seroconvert within 5.8 (0.6) months. HIV infection for longer than 6 months without detectable antibody seems uncommon.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Natural history of acquired immunodeficiency syndrome in women in Rhode Island.

PURPOSE: Current recommendations for treatment of human immunodeficiency virus (HIV) infection and for prophylaxis against associated opportunistic infections in North America are largely based on observations of HIV infection in males. In an effort to determine whether the natural history and clinical course may be different, with implications relevant to prophylaxis against opportunistic infections, we have documented the clinical courses of the first 24 known cases of acquired immunodeficiency syndrome (AIDS) in women in Rhode Island, most of whom developed Centers for Disease Control-defined AIDS before the availability of an effective antiviral agent (i.e., zidovudine) or a well-defined approach to prophylaxis against opportunistic infections (e.g., oral trimethoprimsulfa). PATIENTS AND METHODS: The subjects in this study are 24 women with AIDS who were treated by members of the Brown University medical faculty from June 1982 through June 1988. All patients had thorough clinical evaluations and appropriate laboratory studies as they became available. All were followed at intervals no greater than two months. All opportunistic infections were treated by appropriate, specific antimicrobial therapy. When zidovudine became available, it was administered to all remaining patients in the study. All subjects were counseled about HIV infection, its modes of transmission, and the early symptoms of opportunistic infections. RESULTS: These observations yielded the following three major findings: (1) Candida esophagitis was the most common (38%) AIDS-defining event; (2) Pneumocystis carinii pneumonia was less frequently the AIDS-defining event (13%) and occurred less commonly during the illness (29%) than in North American males with AIDS; (3) Of 14 women in whom the diagnosis of AIDS was established before January 1, 1987, the mean survival time after diagnosis was greater than 20 months. CONCLUSION: More information on the natural history of HIV infection in North American women is urgently needed. If more extensive data from other geographic regions confirm the observations in this study, the optimal approach to prophylaxis against opportunistic infections in women with AIDS may be substantially different from that which is most appropriate for males.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Investigation of a food-borne outbreak of salmonellosis among hospital employees.

An explosive outbreak of Salmonella enterocolitis developed in 27 hospital employees in an acute-care community hospital in Rhode Island in 1987. Salmonella typhimurium was isolated from the stools of 19 employees during the outbreak. In each patient the implicated organism had an identical antibiotic susceptibility pattern, biotype, plasmid profile, and restriction endonuclease digestion pattern. The outbreak was limited to health care workers and other hospital employees; there were no cases in hospitalized patients. Of the afflicted employees 96% ate in the hospital cafeteria on July 11 or 12, 1987. Food-specific attack rates, based on the dietary histories of ill employees and 50 healthy employees who ate in the cafeteria that weekend, indicated an association between the ingestion of salads and illness (p less than 0.01). One food service employee, in whom symptoms of abdominal cramping and diarrhea had developed 6 days earlier, had prepared the implicated foods. S. typhimurium with the identical characteristics of the outbreak strain was isolated from the stools of this food service employee. Environmental cultures and cultures of meat, poultry, and dairy sources for the cafeteria all showed negative results. Food service employees need to be counseled against working during any symptomatic enteric illness and require thorough instruction on hygienic food handling.

Adult↗
PubMed1989

Infectiousness of HIV between male homosexual partners.

To estimate the risk of transmission of HIV per receptive anal sexual contact, 329 homosexually-active men, representing 155 sexual partnerships, were enrolled into a study. Information on HIV infection status and sexual behavior within and outside the primary relationship was collected. Of these 329 men, 24 had AIDS and 31 had ARC. Of the 155 couples, 35 consisted of partners that were both HIV +; 62 of partners that were both HIV-; and 58 were discordant. A binomial model was fit to data obtained in the first visit to estimate per contact risk of HIV transmission. Assuming a constant risk of transmission per sexual contact between infected and uninfected partners, the estimated risk is about 5 to 30 per 1000 receptive anal exposures to ejaculate. Although the average risk of HIV transmission per sexual contact appears to be low, there appears to be great variability in infectivity. To model this variability over time and across individuals, more complex models must be fit to longitudinal studies of sexual partners.

AIDS-Related Complex↗
PubMed1989

Modification of homogeneous resistance in a methicillin-resistant strain of Staphylococcus aureus by acquisition of a beta-lactamase encoding plasmid.

Nearly all clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) are heterogeneously resistant and produce beta-lactamases which generally are plasmid mediated. In order to study the role of beta-lactamase plasmids in the expression of methicillin resistance, a beta-lactamase plasmid from Enterococcus faecalis HH22 (pBEM10) was transferred into a homogeneously resistant, beta-lactamase-negative strain of MRSA (MUSC284). By single disc diffusion testing at 42 degrees C, beta-lactamase producing transconjugants (SA-MM1) were found to be more susceptible than the parent strain to methicillin, imipenem, SCH 34343 and cloxacillin, but more resistant to piperacillin. The heterogeneity observed in transconjugants was not affected by the addition of clavulanic acid, indicating that beta-lactamase itself was not responsible for this effect. By population analysis over 50% of MUSC284 colonies and less than 1% of SA-MM1 colonies remained viable after incubation at 42 degrees C in agar plates containing 25 mg/l of cloxacillin. Cured derivatives of SA-MM1 reverted to homogeneous resistance to beta-lactam antibiotics as observed in the initial parenteral strain MUSC284. Thus, the introduction of a beta-lactamase coding plasmid into a homogeneously resistant MRSA yielded transconjugants which resembled heterogeneously resistant strains of MRSA. These results suggest that regulatory genes, capable of altering the expression of methicillin resistance, may be located on beta-lactamase plasmids commonly found in these organisms.

Chromosomes, Bacterial↗
PubMed1989

Predictors of AIDS-preventive behavior among homosexually active men: a longitudinal study.

Predictors of adoption of safer sexual behaviors were examined in a cohort of 278 homosexually active men with stable HIV-antibody status followed over 12 months at a Boston community health center. The behaviors examined included: (1) restriction of partners to one monogamous or steady relationship and (2) among men who maintained multiple or non-steady partners, the avoidance of unprotected receptive and insertive anogenital contact. For each behavior, men who adopted consistently safer behavior were compared with those who remained unsafe, using bivariate analyses and multiple logistic regression modelling. The strongest predictor of all behaviors was the initial level of the unsafe behavior. After controlling for this, weak effects of several health beliefs were found, including perceived susceptibility and medical efficacy. Men who became aware of a positive HIV-antibody test result and who reported greater effort to change their behavior were more likely to adopt safer insertive anogenital contact. In this generally well-educated cohort with high levels of knowledge about AIDS, adoption of safer sexual behaviors is best predicted from previous levels of unsafe behavior.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Serum inhibitory and bactericidal activity of ciprofloxacin following intravenous administration.

Serum inhibitory and bactericidal titers were measured in nine healthy volunteers following single iv doses of ciprofloxacin 100, 150, and 200 mg. The median peak serum bactericidal titer (5 minutes following completion of a 30-minute infusion) against two highly susceptible strains of Escherichia coli ranged between 1:64 and 1:1024 and titers exceeded 1:8 for six hours for all dose levels. The bactericidal titers against two strains of Pseudomonas aeruginosa and a methicillin-resistant strain of Staphylococcus aureus were considerably lower, the median peak being 1:2 at all dose levels. Measured inhibitory and bactericidal titers at five minutes and one hour postinfusion were significantly greater than those predicted (measured serum ciprofloxacin concentration to minimum inhibitory concentration [MIC] or minimum bactericidal concentration [MBC]) for only one strain of E. coli. Intravenous doses of ciprofloxacin 100-200 mg produce high and sustained serum bactericidal titers against highly susceptible bacteria; considerably lower levels of activity are seen against bacteria having higher MICs and MBCs but still considered susceptible to the drug.

Adult↗
PubMed1989

Increased suppressor T cells in probable transmitters of human immunodeficiency virus infection.

To evaluate behavioral and immunologic factors related to transmission of human immunodeficiency virus (HIV) by homosexual intercourse, we studied a population of 329 homosexual/bisexual men (155 partner-pairs) seen in a community health center and medical outpatient clinic. Logistic regression analysis showed that behavioral risk factors for infection in the 130 HIV-infected men included: receptive anal intercourse (OR 4.6, 95% CI-1.8, 12.1); receptive fisting (OR 2.5, CI-1.1, 7.0); nitrite use (OR 2.3, CI-1.2, 4.6); history of gonorrhea or syphilis (OR 2.3, CI-1.4, 3.9); and history of sexual contact with men from areas with many AIDS cases (OR 1.9, CI-1.0, 3.5). Comparing seven men who were probable transmitters of HIV and 11 men who had not transmitted HIV to their uninfected partners despite unprotected insertive anal intercourse, we found no differences in HIV isolation from peripheral blood mononuclear cells, circulating HIV antigen detection, or presence of neutralizing antibody to HIV. Helper T-cell numbers were not significantly different between the two groups, but transmitters had more suppressor T-cells than did nontransmitters.

AIDS-Related Complex↗
PubMed1989

Unusual nosocomial pathogens.

Multiple factors, including the widespread use of antibiotics, the spread of bacterial resistance plasmids and transposons, and the increased use of invasive procedures in traumatized or immunocompromised patients, have abetted the emergence of constant changes in the nosocomial microflora with selection for highly resistant and virulent bacteria. The introduction of new technologies, including enhanced life support techniques ranging from blood products to parenteral nutrient supplementation, also afford opportunities for previously nonpathogenic organisms to take advantage of new niches. Changes in the inanimate environment, such as ventilatory systems, and changes in personnel and infection control protocols (for example, disinfectants) may also alter the resident nosocomial flora. The resultant challenges to clinicians are to be aware of changes in the prevalence of different organisms and susceptibility patterns in the local hospital and community, and to be knowledgeable about new anti-microbial agents that have activity against multiply resistant pathogens. Judicious antibiotic use and careful application of hospital infection control measures are likely to be effective in meeting these challenges. Ongoing clinical and molecular epidemiological studies are required to better anticipate the emergency and spread of new, distinctive nosocomial pathogens.

Cross Infection↗
PubMed1988

Lymphocytic bronchiolitis associated with HIV infection.

Patients with the acquired immune deficiency syndrome (AIDS) frequently develop interstitial lung disease. This is due most commonly to opportunistic infections, but malignancy and lymphocytic interstitial pneumonitis have also been associated with the syndrome. In contrast, there has been little reported about airways disease in patients with HIV infection. We describe a patient with AIDS-related complex who presented with symptoms and radiographic evidence of micronodular interstitial lung disease. Transbronchial biopsy revealed a lymphocytic bronchiolitis but no evidence of interstitial lung disease and a marked T-suppressor lymphocytosis was found on analysis of the bronchoalveolar lavage (BAL) specimen. Routine fungal, viral and bacterial cultures did not yield an etiologic agent. This case raises the possibility that lymphocytic bronchiolitis may represent another pulmonary manifestation of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Behavioral risk factors for HIV infection among homosexual men at a Boston community health center.

Social and behavioral factors associated with human immunodeficiency virus (HIV) infection were analyzed using cross-sectional data from homosexual and bisexual male clients of a Boston community health center. Partners from California, and a previous period of greater sexual activity (a "high period"), were independently associated with positive HIV antibody status, as were the frequency of receptive anogenital contact, both during the "high period" and during the last six months.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Effects of HIV antibody test knowledge on subsequent sexual behaviors in a cohort of homosexually active men.

This study assesses the effects of HIV (human immunodeficiency virus) antibody testing on subsequent (one year) sexual behavior among 270 homosexual men at a Boston community health center, 21 per cent of whom were unaware of their test result. Except for the number of steady partners, the levels of all sexual activities of all groups of study participants declined over time. No effects of test awareness of antibody status were found on protective behavior for receptive anogenital contact. Elimination of unprotected insertive anogenital contact (by elimination of the practice or by condom use) was reported somewhat more often among seropositive men who became aware of their test result. Increased negative emotional reactions were reported by HIV seropositive men who were aware of their test result. These results suggest some behavioral impact of HIV antibody test knowledge in this cohort, but may not be generalizable to other populations.

Acquired Immunodeficiency Syndrome↗