Microbial exposure of rural school children, as assessed by levels of N-acetyl-muramic acid in mattress dust, and its association with respiratory health

BACKGROUND: Endotoxin exposure has been shown to be associated with a decreased prevalence of atopic sensitization and symptoms. Yet endotoxin represents only a part of the indoor microbial exposure. Muramic acid, a constituent of peptidoglycan, is present in gram-negative and gram-positive bacteria in the environment and may therefore serve as an additional marker of microbial exposure. OBJECTIVE: To study the factors determining the level of indoor exposure to muramic acid/peptidoglycan, as well as its potential association with respiratory health. METHODS: In 553 farm and nonfarm school children from Austria, Switzerland, and Germany, mattress dust muramic acid concentrations were determined, and health was assessed by using IgE measurements and questionnaire information. RESULTS: The muramic acid concentration was found to be significantly higher in dust from farm children's mattresses than in dust from nonfarm children's mattresses (157 vs 131 ng/mg). Children with higher mattress dust muramic acid concentrations had a significantly lower prevalence of wheezing (odds ratio of highest vs lowest tertile of muramic acid concentration, 0.3; 95% CI, 0.1-0.9), regardless of farming status and endotoxin exposure. The association for asthma was similar, and no association was found with atopic sensitization. CONCLUSION: Next to endotoxin, muramic acid provides us with an independent marker of microbial exposure. Unlike endotoxin, muramic acid was inversely associated with wheezing rather than with atopic sensitization.     

Can One be a Good Doctor and have a Sexual Relationship with One's Patient?

This paper presents a qualitative exploration of social andsexual contact between general practitioners and their patients.Social contacts have been implicated in the development of sexualrelationships between members of the mental health professionsand their patients. However, there has been little examinationof the implications for general practitioners. Six focus groupswere conducted by teleconference with New Zealand general practitioners.Participant anonymity was maintained. Questions focused on issuesof social and sexual contact in general practice. Major themeswere extracted from the data. A range of definitions of ‘patient’,‘sexual contact’ and ‘social contact’were offered by the participants which demonstrated that ‘greyareas’ existed for them in relation to social and sexualrelationships with patients. Mandatory reporting of colleaguesfor alleged sexual misconduct was not supported, informal mechanismsbeing preferred. General practitioners need to be aware of potentialboundary violations in their practice. These issues are alsoimportant to address in the teaching of medical students, continuingmedical education, and in the development of appropriate guidelinesfor general practice.     

HIV risk-taking behaviour among injecting drug users currently, previously and never enrolled in methadone treatment

This study compares the injecting and sexual risk-taking behaviour among injecting drug users (IDUs) currently, previously and never enrolled in methadone maintenance treatment (MMT). All subjects had injected during the 6 months prior to the day of interview. The current MMT group showed significantly lower injecting risk-taking behaviour subscale scores on the HIV Risk-taking Behaviour Scale (HRBS) of the Opiate Treatment Index than the previous MMT and non-MMT groups together. The current MMT group differed from the other two groups in the frequency of injecting and cleaning of injection equipment with bleach. There was no difference between the current MMT group and the other two groups combined in sexual risk-taking behaviour scores on the HRBS. There were no differences between the previous MMT and non-MMT groups in injecting and sexual risk-taking behaviour. HIV seroprevalence was low and there was no difference in seroprevalence between groups. Thus, IDUs currently enrolled in MMT are at reduced risk for HIV infection when compared with IDUs who have previously or never been enrolled in MMT. However, the absence of a difference between the current MMT and other two groups in frequency of sharing behaviours suggests the need for additional strategies among MMT clients to reduce needle-sharing. Possible strategies include the application of relapse prevention interventions and the availability of sterile injecting equipment in MMT clinics. Further research is needed to identify factors which increase attraction and retention of IDUs to MMT.     

THE MESSAGE SEQUENCE OF α-MELANOTROPIN: DEMONSTRATION OF TWO ACTIVE SITES

The purpose of this investigation was to elucidate the biological significance of lysine¹¹ and of the tripeptide sequence -Lys-Pro-Val-NH₂ for the biological activity of α-melanocyte-stimulating hormone. To this end the in vitro melanotropic activities of twenty-four synthetic peptides related to the hormone were determined. Extension or reduction of the length of the lysine¹¹ side chain results in a marked decrease of the melanotropic potency of the respective analogue. The C-terminal tripeptide (11-13), the tetrapeptide (10-13), and the pentapeptide (9-13) were found to be hormonally active in the same order of magnitude as the central hexapeptide (5-10). The following conclusion was drawn: α-MSH possesses (in contrast to ACTH) two message sequences (active sites), (i) -Glu-His-Phe-Arg-Trp-, and (ii) -Gly-Lys-Pro-Val-NH₂ which are capable of independently triggering the hormone receptor responsible for melanin dispersion. Thus, despite the close structural similarity of the two hormones, α-MSH and ACTH appear to react with their respective target cell receptors by quite different chemical mechanisms, implying different receptor structures.     

Research at the Auction Block

The “fair benefits” approach to international research is designed to produce results that all can agree are fair without taking a stand on divisive questions of justice. But its appealing veneer of collaboration masks ambiguities at both a conceptual and an operational level. An attempt to put it into practice would look a lot like an auction, leaving little reason to think the outcomes will satisfy even minimal conditions of fairness.