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Biomedical subjects

A L Weightman

Publications and source records attributed to A L Weightman.

5 recordsLinked to original sources

Modification of the home environment for the reduction of injuries.

BACKGROUND: Injury in the home is extremely common, accounting for around a third of all injuries. The majority of injuries of children under five and people aged 75 and over occur at home. Multi-factorial injury prevention interventions have been shown to reduce injuries in the home. However, few studies have focussed specifically on the impact of physical adaptations to the home environment and the effectiveness of such intervention needs to be ascertained. OBJECTIVES: To review the evidence for the effect on injuries of modification of the home environment with a primary focus on interventions to reduce physical hazards. SEARCH STRATEGY: We searched the following databases: APId, ASSIA, British Nursing Index, CINAHL, Cochrane Library databases, Dissertation Abstracts, EMBASE, HealthSTAR, ICONDA, ISI Science (and Social Science) Citation Index, MEDLINE, National Research Register, PREMEDLINE, SIGLE and Urbadisk. Conference proceedings and reference lists were scanned. Experts in the field and trialists were contacted. Searches were not restricted to English language. Handsearching of relevant journals was not conducted. SELECTION CRITERIA: Randomised controlled trials, non-randomised controlled trials, controlled before-and-after studies and interrupted time series studies. DATA COLLECTION AND ANALYSIS: All abstracts were screened by two reviewers for relevance, outcome and design. Two reviewers independently evaluated methodological quality and extracted data from each eligible study. MAIN RESULTS: We found 28 published trials and one unpublished study. Trials were not sufficiently similar to allow for the combination of data by statistical analyses, so this review takes a narrative form. Studies were divided into three groups based on the primary population sample: children, older people and the general population. None of the 11 childhood studies demonstrated a reduction in injuries that might have been due to environmental adaptation in the home. One study reported a reduction in injuries and in hazards but the two could not be linked. The majority of studies used hazard reduction as the outcome. Of the 15 studies in older people, none demonstrated a reduction in injuries due to hazard reduction, although two demonstrated a reduction in falls that could be due to hazard reduction. In the mixed age group there were two trials; neither demonstrated an effect on injuries. REVIEWER'S CONCLUSIONS: There is insufficient evidence to determine the effects of interventions to modify environmental home hazards. Further interventions to reduce hazards in the home should be evaluated by adequately designed randomised controlled trials measuring injury outcomes. Recruitment of large study samples to measure effect may be a major consideration for future trials.

Accidents, Home↗

Taking STOX: developing a cross disciplinary methodology for systematic reviews of research on the built environment and the health of the public.

STUDY OBJECTIVE: To develop a cross disciplinary literature search methodology for conducting systematic reviews of all types of research investigating aspects of the built environment and the health of the public. DESIGN: The method was developed following a comprehensive search of literature in the area of housing and injuries, using 30 databases covering many disciplines including medicine, social science, architecture, science, engineering, environment, planning and psychology. The results of the database searches, including the type (or evidence) of research papers identified, were analysed to identify the most productive databases and improve the efficiency of the strategy. The revised strategy for literature searching was then applied to the area of neighbourhoods and mental health, and an analysis of the evidence type of references was carried out. In recognition of the large number and variety of observational studies, an expanded evidence type classification was developed for this purpose. MAIN RESULTS: From an analysis of 722 citations obtained by a housing and injuries search, an overlap of only 9% was found between medical and social science databases and only 1% between medical and built environment databases. A preliminary evidence type classification of those citations that could be assessed (from information in the abstracts and titles) suggested that the majority of intervention studies on housing and injuries are likely to be found in the medical and social science databases. A number of relevant observational studies (10% of all research studies) would have been missed, however, by excluding built environment and grey literature databases. In an area lacking in interventional research (housing/neighbourhoods and mental health) as many as 25% of all research studies would have been missed by ignoring the built environment and grey literature. CONCLUSIONS: When planning a systematic review of all types of evidence in a topic relating to the built environment and the health of the public, a range of bibliographical databases from various disciplines should be considered.

Databases, Bibliographic↗

Toxic effects of chlorinated and brominated alkanoic acids on Pseudomonas putida PP3: selection at high frequencies of mutations in genes encoding dehalogenases.

Mutant strains of Pseudomonas putida PP3 capable of utilizing monochloroacetate (MCA) and dichloroacetate (DCA) as the sole sources of carbon and energy were isolated from chemostat cultures. The mutants differed from the parent strain in that they could grow on products of MCA and DCA dehalogenation (catalyzed by inducible dehalogenases I and II) and were resistant to growth inhibition by the two substrates. The growth inhibition of strain PP3 by MCA, DCA, and other halogenated alkanoic acids was studied. Sensitivity to dehalogenase substrates was related to the expression of the dehalogenase genes. For example, mutants producing elevated levels of one or both of the dehalogenases were sensitive to 2-monochloropropionate and 2-monochlorobutanoate at concentrations which did not affect the growth of strain PP3. P. putida PP1, the parent of strain PP3, was resistant to the inhibitory effects of MCA and DCA. Spontaneous mutants of strain PP3, also resistant to MCA and DCA, were selected at high frequency, and four different classes of these strains were distinguished on the basis of dehalogenase phenotype. All dehalogenase-producing mutants were inducible; no constitutive mutant has yet been isolated. Most of the resistant mutants examined did not produce one or both of the dehalogenase, and over half of those tested failed to revert back to the parental (strain PP3) phenotype, indicating that the observed mutations involved high-frequency deletion of DNA base sequences affecting expression of genes encoding dehalogenases and associated permease(s).

Acetates↗

Stereospecificity of 2-monochloropropionate dehalogenation by the two dehalogenases of Pseudomonas putida PP3: evidence for two different dehalogenation mechanisms.

Pseudomonas putida PP3 grew on DL-2-monochloropropionate (2MCPA) with a release of chloride ions consistent with the dechlorination of both isomers. The organism grew on either D- or L-2MCPA. Dehalogenase activity in cell-free extracts showed that both D- and L-2MCPA were dehalogenated. Pseudomonas putida PP3 contains two dehalogenases, and studies with the separated enzymes revealed that the fraction I enzyme used both D- and L-2MCPA, the rate of dechlorination of L-2MCPA being 80% of the rate of D-2MCPA dechlorination. The product of the reaction, lactate, retained the same optical configuration as the substrate provided. The fraction II dehalogenase also dechlorinated D- and L-2MCPA, with the same difference in rates as for the fraction I dehalogenase, but the lactates produced were of the opposite configuration to their precursors. The two dehalogenases showed further differences with respect to inhibition by two sulphydryl-blocking agents, N-ethylmaleimide and p-chloromercuribenzoate. Fraction I dehalogenase was considerably more sensitive to these two reagents compared with the fraction II dehalogenase. Dithiothreitol partially protected the fraction I dehalogenase from N-ethylmaleimide inhibition. The results are discussed in terms of the possible evolutionary relationships of the two dehalogenases.

2-Methyl-4-chlorophenoxyacetic Acid↗