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Biomedical subjects

E Warren

Publications and source records attributed to E Warren.

At least 19 recordsLinked to original sources
PubMed2001

Progression of natural attenuation processes at a crude oil spill site: II. Controls on spatial distribution of microbial populations.

A multidisciplinary study of a crude-oil contaminated aquifer shows that the distribution of microbial physiologic types is strongly controlled by the aquifer properties and crude oil location. The microbial populations of four physiologic types were analyzed together with permeability, pore-water chemistry, nonaqueous oil content, and extractable sediment iron. Microbial data from three vertical profiles through the anaerobic portion of the contaminated aquifer clearly show areas that have progressed from iron-reduction to methanogenesis. These locations contain lower numbers of iron reducers, and increased numbers of fermenters with detectable methanogens. Methanogenic conditions exist both in the area contaminated by nonaqueous oil and also below the oil where high hydrocarbon concentrations correspond to local increases in aquifer permeability. The results indicate that high contaminant flux either from local dissolution or by advective transport plays a key role in determining which areas first become methanogenic. Other factors besides flux that are important include the sediment Fe(II) content and proximity to the water table. In locations near a seasonally oscillating water table, methanogenic conditions exist only below the lowest typical water table elevation. During 20 years since the oil spill occurred, a laterally continuous methanogenic zone has developed along a narrow horizon extending from the source area to 50-60 m downgradient. A companion paper [J. Contam. Hydrol. 53, 369-386] documents how the growth of the methanogenic zone results in expansion of the aquifer volume contaminated with the highest concentrations of benzene, toluene, ethylbenzene, and xylenes.

Bacteria, Aerobic↗
PubMed2001

Why do GPs not implement evidence-based guidelines? A descriptive study.

BACKGROUND: There is an acknowledged gap between research findings and their implementation in clinical practice despite the existence of effective educational interventions. OBJECTIVES: Our aim was to identify what is impeding GPs from pursuing currently recognized good practice and implementing evidence-based guidelines in their management of hypertension in the elderly. METHOD: We carried out a qualitative study using semi-structured interviews conducted during focus group outreach visits to 34 GPs from nine practices in Merseyside involved in an educational programme designed to improve the management of hypertension in the elderly. RESULTS: Several barriers to the implementation of evidence-based guidelines in the management of hypertension in the elderly were identified. These included: doubts about the applicability of trial data to particular patients; the poor adherence of GPs to practice protocols; ageist attitudes of some GPs; the effect of time pressure and financial considerations making the subject a low priority; the absence of an effective computer system; and the absence of an educational mentor. All participants demonstrated a very positive attitude to practice-based education. They also welcomed external audit data, which compared their performance with that of other practices. Single-handed GPs were particularly enthusiastic about this approach as it provided them with the peer pressure they lacked. CONCLUSIONS: In order to bridge the gap between research and practice, educators need to address the various 'barriers to change' amongst practitioners.

Evidence-Based Medicine↗
PubMed1999

Distribution of Microbial Physiologic Types in an Aquifer Contaminated by Crude Oil.

> Abstract We conducted a plume-scale study of the microbial ecology in the anaerobic portion of an aquifer contaminated by crude-oil compounds. The data provide insight into the patterns of ecological succession, microbial nutrient demands, and the relative importance of free-living versus attached microbial populations. The most probable number (MPN) method was used to characterize the spatial distribution of six physiologic types: aerobes, denitrifiers, iron-reducers, heterotrophic fermenters, sulfate-reducers, and methanogens. Both free-living and attached numbers were determined over a broad cross-section of the aquifer extending horizontally from the source of the plume at a nonaqueous oil body to 66 m downgradient, and vertically from above the water table to the base of the plume below the water table. Point samples from widely spaced locations were combined with three closely spaced vertical profiles to create a map of physiologic zones for a cross-section of the plume. Although some estimates suggest that less than 1% of the subsurface microbial population can be grown in laboratory cultures, the MPN results presented here provide a comprehensive qualitative picture of the microbial ecology at the plume scale. Areas in the plume that are evolving from iron-reducing to methanogenic conditions are clearly delineated and generally occupy 25-50% of the plume thickness. Lower microbial numbers below the water table compared to the unsaturated zone suggest that nutrient limitations may be important in limiting growth in the saturated zone. Finally, the data indicate that an average of 15% of the total population is suspended.http://link.springer-ny.com/link/service/journals/00248/bibs/37n4p263.html

Journal Article↗
PubMed1998

Hypertension in the elderly: attitudes of British patients and general practitioners.

The perceptions of patients and GPs of the risk of stroke in treated and untreated elderly hypertensives, and their attitudes towards anti-hypertensive therapy were examined. To explore attitudes of patients to the management of hypertension a qualitative approach was used, employing semi-structured interviews, with subsequent thematic analysis of the transcriptions. A questionnaire study of GPs' attitudes to the same subject was also conducted. The elderly (n = 75) greatly overestimate the risks of hypertension and the benefits of treatment. Most would accept anti-hypertensive therapy despite being informed of the true risks, citing confidence in their doctor as the major determinant in their decision. GPs (n = 121) were well informed of the risks and benefits, but less than half adhere to current guidelines. GPs should be aware how much the elderly overestimate the risks of hypertension and the benefits of its treatment. When considering treating hypertension in this group, patient contributions in the treatment decision-making process should be actively encouraged, especially as many elderly hold a deferential attitude towards their doctor. Patients should be informed of the risks of their disease and the benefits of treatment in terms they understand. The use of visual aids helps patients to grasp the difficult concepts of risk and benefit.

Adolescent↗
PubMed1997

The influence of parasympatholytics on the resolution of acute attacks of asthma.

PURPOSE: To evaluate the role of parasympatholytics in the resolution of acute attacks of asthma. METHODS: This study employed a prospective sequential design in which the influence of 0.5 and 1.0 mg of ipratropium bromide on peak expiratory flow rates (PEFR), hospital admissions, and length of stay (LOS) in the emergency department (ED) was evaluated. The parasympatholytic was added to a well-investigated standard therapeutic regimen that was anchored by the use of repetitive doses of albuterol, and employed pretested decision algorithms. RESULTS: One hundred and thirty-one patients received ipratropium (l) and 123 who did not (NI) served as controls. There were no significant pretreatment between group differences in gender, racial composition clinical signs and symptoms, or PEFR. The presence of ipratropium in the regimen did not influence discharge/admission patterns, LOS, the rate of improvement of the patients, or the level of PEFR achieved. CONCLUSION: Anticholinergic agents such as ipratropium are not first-line treatments for acute asthma. They do not add any therapeutic benefit to the effects of albuterol given in divided doses over 1 hour, nor do they facilitate recovery in patients whose immediate response to sympathomimetics is impaired.

Acute Disease↗
PubMed1997

Clinical and human resource planning for the downsizing of psychiatric hospitals: the British Columbia experience.

Riverview Hospital, B.C.'s only and Canada's largest remaining provincial psychiatric hospital began a formal planned "downsizing" process in 1992. This initiative was an important element in the Province's strategic plan to shift to a more community-focused mental health system and to bring tertiary psychiatric services "closer to home" by redeveloping Riverview Hospital on three sites. The paper summarizes the literature pertaining to the "downsizing" of psychiatric hospital services in relation both to clinical and human resource planning. It describes the mental health system in B.C. and the service system context in which this exercise is occurring. It is based on the first three years of experience in identifying the major challenges and the strategies developed to meet these challenges. It draws some conclusions about the effectiveness of these strategies and it speculates about the likely future challenges as the "downsizing" process continues.

British Columbia↗
PubMed1991

Gorilla class I major histocompatibility complex alleles: comparison to human and chimpanzee class I.

14 gorilla class I major histocompatibility complex (MHC) alleles have been isolated, sequenced, and compared to their counterparts in humans and chimpanzees. Gorilla homologues of HLA-A, -B, and -C were readily identified, and four Gogo-A, four Gogo-B, and five Gogo-C alleles were defined. In addition, an unusual Gogo class I gene with features in common with HLA-A and its related pseudogene, HLA-H, is described. None of the gorilla alleles is identical or even closely related to known class I alleles and each encodes a unique antigen recognition site. However, the majority of polymorphic substitutions and sequence motifs of gorilla class I alleles are shared with the human or chimpanzee systems. In particular, elements shared with HLA-A2 and HLA-B27 are found in Gogo-A and -B alleles. Diversity at the Gogo-B locus is less than at the Gogo-A locus, a trend the opposite of that seen for HLA-A and -B. The Gogo-C locus also appears to have limited polymorphism compared to Gogo-A. Two basic Gogo-C motifs were found and they segregate with distinctive sets of HLA-C alleles. HLA-A allels are divided into five families derived from two ancient lineages. All chimpanzee A alleles derived from one of these lineages and all gorilla alleles derive from the other. Unlike chimpanzee Patr-A alleles, the Gogo-A alleles do not clearly partition with one of the HLA-A families but have similarities with two. Overall, gorilla class I diversity appears from this sampling to show more distinctions from class I HLA than found for chimpanzee class I.

Alleles↗
PubMed1985

Tuberculosis as an endemic and nosocomial infection among the elderly in nursing homes.

We studied reactivity to tuberculin skin testing in nearly all nursing home residents in Arkansas. Only 12 per cent of the 12,196 newly admitted residents were tuberculin positive, as compared with 20.8 per cent of the 13,441 residents who were first tested more than a month (mean, 30 months) after admission. The proportion of persons who were positive on initial testing varied greatly with the time spent in the home before testing. Those who were not reactive on initial testing had a 5 per cent rate of conversion for each year spent in a home with a known recent infectious case (within three years) and a 3.5 per cent rate for each year in a home with no recognized recent case. Active tuberculosis developed in only 1 of 534 persons with positive tuberculin tests or previous reactions who were treated with isoniazid, but in 79 (2.4 per cent) of 3270 persons who were not (P less than 0.001). The disease developed in only 1 (0.16 per cent) of 605 persons whose tests converted to positive and who were treated with isoniazid, as compared with 45 (5.9 per cent) of 757 whose tests converted but who were not treated (P less than 0.001). We conclude that new infection with tuberculosis is an important risk for nursing home patients and that greater care should be taken to detect and treat new infections before the disease develops and the infection spreads.

Aged↗
PubMed1985

Epidemic tuberculosis in a nursing home: a retrospective cohort study.

In a retrospective study, the results of tuberculin skin tests done in a nursing home were examined, where most residents admitted during 1972-1981 were tested using purified protein derivative of tuberculin administered intradermally. Of 514 residents who were tested at least once during the study period, results of the admission skin test were available for 254 and follow-up skin test results were available for 226. On admission, 13 per cent (35/254) were skin-test positive (greater than or equal to 10 mm induration at 48 hours). Skin test positivity for males was 16 per cent, females, 11 per cent, nonwhites, 19 per cent, and whites, 12 per cent. Highest skin test positivity was for persons received as transfers from other nursing homes (24 per cent) and lowest was for those entering from individual homes (8 per cent, P = 0.016, Fisher's Exact Test). On follow-up, 38/226 (17 per cent) residents who had been tuberculin-negative on at least two previous occasions were found to be positive; 24 (63 per cent) of these conversions occurred in a single year (1975) following detection of an infectious patient. The infection rate for persons residing in the nursing home during that year was 28 per cent (28/99) compared with 7.9 per cent (10/127) for persons either discharged before or admitted after 1975 (relative risk = 3.6, P less than 0.001). Ten to 15 per cent of new residents are tuberculin-positive (harbour a dormant tuberculous infection), leaving 85-90 per cent of newly admitted persons who are tuberculin-negative and thus susceptible to infection if exposed. The study shows that tuberculosis must be considered as a potential nosocomial infection in nursing homes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Free oxygen radicals are not detectable by chemiluminescence during human natural killer cell cytotoxicity.

Mononuclear cells isolated from peripheral blood of normal donors produce free oxygen radicals (FR), detectable by chemiluminescence (CL), when interacting with target cells during natural killer (NK) cell lysis. FR-producing cells were found to have monocyte characteristics and gave a positive CL reaction when mixed at low concentration (0.5%) with purified NK cells. No correlation was found between susceptibility to NK cell lysis and capacity to induce CL with different target cell lines. Using high and low molecular FR scavengers, no NK cell inhibition was seen with superoxide dismutase, cytochrome c, and catalase, whereas some inhibition was seen with 4,5-dihydroxy-m- benzenedisulphonic acid (Tiron) and 2,3-dihydroxybenzoate. These compounds, however, required higher concentrations than used for inhibition of CL, suggesting an alternative action of these compounds. Normal levels of NK cell activity were found in two patients with chronic granulomatous disease, who were genetically incapable of producing detectable amounts of FR. As a result, it is concluded that human NK cells do not produce large amounts of FR during killing and that FR are unlikely to be the lytic end product. Nevertheless, neither a low degree of FR formation in NK cells nor a more subtle signal-transmitting role of FR during NK cell triggering can be excluded.

1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium ↗