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Biomedical subjects

M Evans

Publications and source records attributed to M Evans.

At least 199 records · Page 11Linked to original sources
PubMed1996

The static and dynamic behaviour of tibial fractures due to unlocking external fixators.

OBJECTIVE: To determine how the mechanical environment of a tibial fracture is influenced by unlocking an external fixator frame. DESIGN: A clinical study examined 10 consecutive patients fixed with the Orthofix DAF. BACKGROUND: It has been claimed that the healing of diaphyseal tibial fractures is assisted by unlocking external fixators to allow free axial movement, but the influence on the mechanical environment at the fracture has not been established. METHODS: A transducer attached to bone screws measured dynamic interfragmentary displacement during walking both before and immediately after unlocking the fixator at 6 weeks in 10 subjects. Four subjects were monitored over the first hour after unlocking to measure interfragmentary gap shortening. RESULTS: Mean peak amplitudes of cyclical axial and angular displacement before unlocking were 0.46 mm (SD 0.27) and 0.37 degrees (SD 0.30), and after were 0.42 mm (SD 0.19) and 0.34 degrees (SD 0.28). Mean peak torsional and transverse shear displacements were 0.21 degrees (SD 0.11) and 0.30 mm (SD 0.17) before unlocking, and after were 0.42 degrees (SD 0.39) and 0.51 mm (SD 0.60). Gaps shortened permanently by unrecoverable axial translations of between 0.2 and 1.4 mm; the mean was 0.69 mm. CONCLUSIONS: Unlocking was found more often to reduce both axial and angular motion, but to increase shear. Overall, this may reduce maximum longitudinal strains in the external callus. The reduced motion may arise from gap shortening.

Journal Article↗
PubMed1996

The Women's Health Trial Feasibility Study in Minority Populations: design and baseline descriptions.

The Women's Health Trial: Feasibility Study in Minority Populations (WHT:FSMP), a randomized trial of 2208 women, was conducted to investigate three questions. First, can women from minority and low-socioeconomic-status populations be recruited in numbers sufficient to evaluate a dietary intervention designed to lower fat intake. Second, the efficacy of a low fat, increased fruit/vegetable/ grain product intervention for reducing fat consumption. Third, will participation in the intervention lower plasma cholesterol and estradiol levels relative to the controls. The baseline results showed that an adequate number of minority and low SES women could be recruited to test the study hypotheses. A diverse study population of postmenopausal women consuming a high fat diet was recruited: 28% of participants were Black, 16% were Hispanic, 11% had less than a high school level of education, and 15.5% had household incomes of < $15,000.

Aged↗
PubMed1996

Helicobacter pylori in dental plaque and gastric mucosa.

OBJECTIVE: The aim of this study was to investigate the presence of Helicobacter pylori in both dental plaque and gastric mucus. STUDY DESIGN: Dental scaling hand instruments were used to collect supragingival and subgingival dental plaque from 81 dentate participants. Denture plaque was obtained from the fitting surfaces of dentures from 41 edentulous patients. Gastric mucus from gastric mucosa of antrum and body of stomach were collected from all 122 participants (92% white) with soft gastroscopic brush. These samples were dispersed in modified urea broth and normal saline solution before being inoculated onto selective Skirrow's agar and incubated in a microaerophilic atmosphere for culturing H. pylori. RESULTS: Dental plaque from all dentate participants was negative for H. pylori culture. Only one 80-year-old edentulous patient had positive H. pylori culture in both gastric mucus and denture plaque. CONCLUSIONS: Although dental plaque has a mixed flora that may act as a reservoir for gastric reinfection, dental plaque could not be implicated as the major reservoir of H. pylori for gastric reinfection.

Aged↗
PubMed1996

Medroxyprogesterone acetate enhances the spinal bone mineral density response to oestrogen in late post-menopausal women.

OBJECTIVES: The relative contributions of administered oestrogen and progestin to protection of the post-menopausal skeleton remain unclear. We have compared the effect on spinal bone mineral density of continuous combined oestrogen/medroxyprogesterone therapy with that of unopposed oestrogen in late post-menopausal women. DESIGN: Observational study. SUBJECTS: Seventy-three osteoporotic post-menopausal women attending the Auckland Hospital Bone Clinic. Twenty-three hysterectomized women were treated with unopposed oestrogen (0.625 mg oral conjugated oestrogens daily), and 50 non-hysterectomized women were treated with continuous combined oestrogen/medroxyprogesterone therapy (5 mg medroxyprogesterone acetate and 0.625 mg oral conjugated oestrogens daily). MEASUREMENTS: Baseline and one-year measurements of lumbar spine bone mineral density were performed using dual-energy X-ray absorptiometry. RESULTS: After one year of therapy, spinal bone mineral density increased by 6.6% (95% confidence interval 5.6-7.6, P < 0.001 vs baseline) in the combined oestrogen/medroxyprogesterone therapy group, compared to 4.0% (CI 2.4-5.7, P < 0.001 vs baseline) in the unopposed oestrogen group (difference between means 2.6% (CI 0.8-4.4, P < 0.01). CONCLUSION: In osteoporotic post-menopausal women, one year of continuous combined oestrogen/medroxyprogesterone therapy is associated with a 65% greater increment in spinal bone mineral density than is observed in response to unopposed oestrogen. The prescription of combined oestrogen/progestin therapy should be considered in osteoporotic post-menopausal women who have undergone hysterectomy, in order to maximize the skeletal protection provided by hormone replacement therapy.

Absorptiometry, Photon↗
PubMed1996

Developing a new method to record care at home for children with cancer: an example of research and practice collaboration in a regional paediatric oncology unit.

Academics need to address the facilitation of nurses in practice to research and develop the care given to patients if nursing is to move closer towards a research-based profession. This paper describes a project involving collaboration between an academic department of nursing and nurses working in clinical practice providing care at home for children with cancer. The project involved an audit of the nursing care records for the service, and the development of a new style of record-keeping which described and quantified complex nursing care. The authors discuss the method and results of the project, describing the benefits of research and practice collaboration.

Child↗
PubMed1996

An instrumented spacial linkage for monitoring relative three-dimensional motion between fracture fragments.

A mechanical linkage with electro-magnetic sensors (a displacement transducer) is described, which may be used to measure accurately the relative motion at a bony junction such as a fracture. The linkage may be fixed to bone screws of externally-fixated fractures during routine patient activity, to measure three-dimensional inter fragmentary displacements arising from dynamic loading. Movements of the linkage are monitored by six Hall Effect devices for the six degrees of freedom (three orthogonal translations and three rotations about the translating axes). Measurements are made within error bounds of +/- 0.025 mm and +/- 0.025 deg over a range of 5 mm for the two orthogonal transverse translations, 8 mm for axial translation and 8 deg for the three rotations. Movements at the linkage, remote from the fracture, are then translated mathematically to the fracture site, assuming rigid screw contact with the bone. Displacements of the distal fragment in relation to the proximal, at the fracture center, can then be expressed anatomically through anterior, medial, and distal translations, and rotations in the sagittal, coronal, or transverse planes.

Biomechanical Phenomena↗
PubMed1996

Clonal diversity of Streptococcus mitis biovar 1 isolates from the oral cavity of human neonates.

The clonal diversity of 101 isolates of the pioneer bacterium Streptococcus mitis biovar 1 obtained from the oral cavities of 40 human neonates 1 to 3 days, 2 weeks, and 1 month postpartum was examined by using rRNA gene restriction patterns. There was a high degree of genetic diversity, with the 101 isolates comprising 93 unique PvuII ribotypes. There were eight identical pairs of ribotype patterns, and seven of the eight pairs were obtained from individual neonates. Only one identical pair comprised isolates obtained from different neonates. In all but two cases, isolates with matching ribotypes were obtained at one visit. Two pairs of isolates with matching ribotype patterns were obtained from neonates on successive visits. The ribotype patterns of the isolates were examined by cluster analysis. The isolates forming each cluster were very similar, yet each cluster was well separated from its neighbors. When several isolates were obtained from individual neonates at a particular visit, in some instances they were contained in a single cluster, whereas in other cases each isolate was contained in a separate cluster. Isolates obtained from individual neonates on successive visits tended to be contained in different clusters. This high degree of diversity, which has been observed in other mucosal commensal bacteria, may serve as a mechanism for avoiding immune elimination of these bacteria.

Cloning, Molecular↗
PubMed1996

Can a lecture influence attitudes to suicide prevention?

Attitudes held by various groups of healthcare professionals with regard to suicide prevention were assessed using an attitude inventory before and after they attended a formal lecture. The lecture presented basic facts and statistics, discussed clinical techniques and challenged negative attitudes. Evidence is presented to suggest that a reduction in the proportion of expressed attitudes which were equivocal or negative towards the feasibility of suicide prevention in clinical practice, can be achieved by a lecture of this kind.

Attitude of Health Personnel↗
PubMed1996

Educating psychiatric patients about their treatment: do fact sheets work?

Psychiatric patients are sometimes given fact sheets about their treatment but the benefits of these are uncertain. We tested three strategies in three cohorts of psychiatric inpatients--fact sheets alone, fact sheets and subsequent discussion, and control. Knowledge of medication was assessed by questionnaire. For various reasons, only 33 of the 77 patients were included in the study or analysis. Of the patients who had been given fact sheets, 87% independently read them and reported finding them helpful whilst all asked for more information. Receiving a fact sheet alone had no significant effect, whereas having discussed it with a health care professional was associated with a significant increase in knowledge about medication. Patients receiving fact sheets selectively learned more about side-effects than about drug action or precautions. This strategy for patient education could be used by ward nurses and deserves further evaluation.

Adolescent↗
PubMed1996

A pilot study to evaluate in-hospital care by mothers.

Believing that family-centered care is beneficial to children with cancer, the staff at Southampton General Hospital in the United Kingdom decided to consider instituting care by parents. Before full implementation of care by parents, a pilot study involving teaching five mothers of pediatric oncology patients how to administer intravenous (i.v.) antibiotics to their child was performed. The basis for selecting antibiotic administration was that if the mothers were capable of performing such a complex task, they would likely be able to be involved in the total care of their child. Mothers' views on the teaching program were sought using taped interviews, and the data were analyzed using a line-by-line constant-comparison analysis. All mothers in the study were capable of performing the procedure and all were willing to do so. Mothers emphasized the fact that they often feel stressed and out of control because of the impact of disease and treatment, and many important issues were raised in relation to this. Nurses' attitudes towards care by parents requires clarifying and changes need to take place if this concept is to progress. Negotiation to allow mutual understanding between parents and nurses is essential to the successful implementation of such a care approach.

Adult↗
PubMed1995

Microwaves for menorrhagia: a new fast technique for endometrial ablation.

Current ablative techniques for treating menorrhagia are unsatisfactory. We tried microwave energy, delivered by an 8 mm diameter probe in the uterine cavity, to treat 23 patients with functional menorrhagia. The mean treatment time was 2 min 12 s (range 50-310 s). 6 months after treatment the success rate is 83%, 13 patients (57%) are amenorrhoeic, and six (26%) are experiencing light menstruation. Three initial failures have been successfully retreated. The technique is safe, and is easier and quicker to perform than current alternatives.

Adult↗
PubMed1995

Disruption of the adenosine deaminase (ADA) gene using a dicistronic promoterless construct: production of an ADA-deficient homozygote ES cell line.

In man, deficiency of ADA activity is associated with an autosomal recessive form of severe combined immunodeficiency (SCID), a disease with profound defects both cellular and humoral immunity. Current treatments of ADA deficient patients include bone marrow transplantation, enzyme replacement and somatic gene therapy. The mechanism of the selective immune cell pathogenesis in ADA-SCIDS is, however, still poorly understood. Thus, the generation of an ADA deficient mouse model will be of considerable benefit to understand better the pathophysiology of the disorder and to improve the gene therapy treatments. We have disrupted the adenosine deaminase (ADA) gene in embryonic stem cells using a new efficient promoter trap gene-targeting approach. To this end, a dicistronic targeting construct containing a promoterless IRES beta geo cassette was used. This cassette allows, via the internal ribosomal entry site (IRES), the direct cap-independent translation of the beta geo reporter gene which encodes a protein with both beta-galactosidase and neomycin activities. After indentification of targeted clones by Southern blot, successful inactivation of the ADA gene was first confirmed by producing, from our heterozygote clones, an homozygote cell line. This line shows no ADA activity as judged by zymogram analysis. Second, we have been able to detect in the targeted clones, a specific beta galactosidase activity using a sensitive fluorogenic assay. The targeted ES cell clones are currently being injected into blastocysts to create an ADA deficient mouse model.

Adenosine Deaminase↗
PubMed1995

Application of Collis gastroplasty to the management of esophageal atresia.

Establishment of esophageal continuity in the presence of an isolated esophageal atresia frequently requires deferred esophageal substitution. The author describes the use of Collis gastroplasty as an esophageal lengthening technique for the distal esophagus. This technique permitted the performance of primary repair of the esophagus in an infant with a 6-cm gap that otherwise would have required an esophageal substitution procedure. Morbidity after this procedure is comparable to that occurring after a number of established techniques.

Anastomosis, Surgical↗
PubMed1995

Trials of Hypertension Prevention, phase II. Structure and content of the weight loss and dietary sodium reduction interventions. Trials of Hypertension Prevention (TOHP) Collaborative Research Group.

Identifying effective, nonpharmacologic means of preventing or significantly delaying the onset of hypertension would be a major advance in the primary prevention of cardiovascular disease. In the first phase of the Trials of Hypertension Prevention (TOHP I), adults with high-normal diastolic blood pressure were randomly assigned to one of seven nonpharmacologic interventions. Only weight loss and reduction of dietary sodium proved to be effective strategies for reducing blood pressure. The second phase of TOHP (TOHP II) will test the effectiveness of weight loss, reduction of dietary sodium, and their combination of lowering blood pressure and preventing the onset of hypertension over a 3- to 4-year follow-up period. This article describes the three interventions used in TOHP II, methods used to maintain continued participation in this long-term trial, and protocol enhancements designed to maximize intervention effectiveness.

Adult↗
PubMed1995

The ultrasonic localization of retrobulbar needles during retrobulbar block.

PURPOSE: The tips of retrobulbar needles were visualized during retrobulbar block using ultrasound. The purpose of this study is to see how often the needle tip was located 5 mm behind the hind surface of the globe. METHODS: Twenty-five patients ranging in age from 22 to 84 years were studied after written informed consent was obtained. An ultrasonic photograph was taken before needle placement, with the needle in the proper position, and after local anesthetic had been injected. RESULTS: In none of the 25 patients studied was the needle tip at the 5-mm mark behind the eye. Placement ranged from 0.2 to 3.3 mm behind the globe. In 14 to 25 placements, the needle shaft was seen actually to indent the globe. The optic nerve was seen to be at least 9 mm from the needle tip in 6 of 25 patients. CONCLUSION: This study demonstrates that retrobulbar needle tips are closer to the globe than thought previously. A false sense of security may occur when performing retrobulbar blocks using only anatomic landmarks.

Adult↗