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Biomedical subjects

M Taylor

Publications and source records attributed to M Taylor.

At least 73 records · Page 4Linked to original sources

Should the cement mantle around the femoral component be thick or thin?

We have compared the survival and radiological outcome at ten years after total hip replacement using two techniques for preparing the femoral canal. The same prosthesis was used throughout and all operations were performed by the same surgical team. In technique 1 the canal was over-reamed by 2 mm and in technique 2 it was reamed to the same size as the prosthesis. Technique 1 was performed on 92 patients and technique 2 on 97 patients. The survival at ten years was 97.2% (90.6 to 99.2) for technique 1 and 98.8% (92.9 to 99.8) for technique 2. Vertical migration was greater in technique 1 (1.8 mm versus 1.0 mm at five years; p = 0.36). There were significantly more lytic lesions and radiolucent lines at five years (p = 0.0061) with technique 1. We conclude that technique 2 is not worse and may produce better long-term results than current teaching suggests.

Aged↗

An epidemiological perspective of substance use among high school pupils in rural KwaZulu-Natal.

OBJECTIVES: To investigate prevalence and the factors influencing substance use among rural high school pupils in KwaZulu-Natal in order to develop and implement intervention programmes. DESIGN: Cross-sectional study. SETTING: Twenty-eight high schools in southern KwaZulu-Natal. SUBJECTS: One thousand three hundred and eighteen grade 10 pupils. OUTCOME MEASURES: An anonymous self-reporting questionnaire was used to investigate the use of alcohol, tobacco (cigarettes), cannabis and solvents. RESULTS: Of the male scholars, 52.9% (95% confidence interval (CI): 45.4-60.3) reported ever using alcohol, 16.9% (CI: 11.5-24.0) reported using cannabis, and 13.1% (CI: 7.2-22.5) had smoked more than one cigarette daily. Among male pupils 45.5% (CI: 38.6-52.6) had inhaled benzine and 34.6% (CI: 28.0-41.8), thinners; 7.4% (CI: 3.4-15.2) had used cocaine and 4.1% (CI: 1.0-10.6), crack. Female pupils reported significantly less use of alcohol (25.5%, CI: 17.6-35.3), cannabis (2.3%, CI: 1.3-4.1), cigarettes (more than one daily) (2.0%, CI: 1.0-4.1), and inhalation of benzine (18.8%, CI: 13.8-25.2) and thinners (10.8%, CI: 7.2-16). Logistical regression indicated that the odds of smoking cigarettes increased significantly (p < 0.0005) with use of the other substances. CONCLUSION: The results of this study confirm the prevalence of multi-substance use among pupils at the majority of rural high schools in this district and the need for targeted interventions to reduce/prevent this.

Adolescent↗

Simulation of a knee joint replacement during a gait cycle using explicit finite element analysis.

The stress distribution within the polyethylene insert of a total knee joint replacement is dependent on the kinematics, which in turn are dependent on the design of the articulating surfaces, the relative position of the components and the tension of the surrounding soft tissues. Implicit finite element analysis techniques have been used previously to examine the polyethylene stresses. However, these have essentially been static analyses and hence ignored the influence of the kinematics. The aim of this work was to use an explicit finite element approach to simulate both the kinematics and the internal stresses within a single analysis. A simulation of a total knee joint replacement subjected to a single gait cycle within a knee wear simulator was performed and the results were compared with experimental data.The predicted kinematics were in close agreement with the experimental data. Various solution-dependent parameters were found to have little influence on the predicted kinematics. The predicted stresses were found to be dependent on the mesh density. This study has shown that an explicit finite element approach is capable of predicting the kinematics and the stresses within a single analysis at relatively low computational cost.

Biomechanical Phenomena↗

New Zealand bicycle helmet law--do the costs outweigh the benefits?

OBJECTIVES: This paper examines the cost effectiveness of the compulsory bicycle helmet wearing law (HWL) introduced in New Zealand on 1 January 1994. The societal perspective of costs is used for the purchase of helmets and the value of injuries averted. This is augmented with healthcare costs averted from reduced head injuries. METHODS: Three age groups were examined: cyclists aged 5-12 years, 13-18 years, and >/=19 years. The number of head and non-head injuries averted were obtained from epidemiological studies. Estimates of the numbers of cyclists and the costs of helmets are used to derive the total spending on new bicycle helmets. Healthcare costs were obtained from national hospitalisation database, and the value of injuries averted was obtained directly from a willingness-to-pay survey undertaken by the Land Transport Safety Authority. Cost effectiveness ratios, benefit:cost ratios, and the value of net benefits were estimated. RESULTS: The net benefit (benefit:cost ratios) of the HWL for the 5-12, 13-18, and >/=19 year age groups was $0.3m (2.6), -$0.2m (0.8), and -$1.5m (0.7) (in NZ $, 2000 prices; NZ $1.00 = US $0.47 = UK pound 0.31 approx). These results were most sensitive to the cost and life of helmets, helmet wearing rates before the HWL, and the effectiveness of helmets in preventing head injuries. CONCLUSIONS: The HWL was cost saving in the youngest age group but large costs from the law were imposed on adult (>/=19 years) cyclists.

Adolescent↗

Is housework good for health? Levels of physical activity and factors associated with activity in elderly women. Results from the British Women's Heart and Health Study.

OBJECTIVE: To determine the prevalence of achieving new recommended levels of physical activity, the types of activity involved, and their determinants among elderly British women. DESIGN: National cross sectional survey. PARTICIPANTS: 2341 women aged 60 to 79 from 15 British towns. MAIN OUTCOME MEASURES: Prevalence of subjects achieving recommended levels of physical activity. RESULTS: Over two thirds of the participants were active at new recommended levels. This was mainly achieved through participation in heavy housework. If domestic activities were excluded only 21% were regularly active. Women who participated in brisk walking for at least 2.5 hours per week had reduced odds of being overweight: odds ratio (95% confidence intervals) 0.5 (0.3 to 0.6) after adjustment for other forms of activity, health status, smoking, and socioeconomic position. Participating in at least 2.5 hours of heavy housework was not associated with reduced odds of being overweight 1.1 (0.8 to 1.4). Age, self reported poor health status, coronary heart disease, and respiratory disease were independently associated with reduced odds of participating in all types of activity. In addition participation in brisk walking and physical exercise were less likely in current smokers, those from the lowest socioeconomic class, and those living in the north of the country. Participation in heavy housework was less likely in women reporting depression but was not associated with smoking, socioeconomic class, or area of residence. CONCLUSIONS: If new physical activity recommendations, which include domestic activities, are used to assess population levels of physical activity then it seems that the majority of elderly women are sufficiently active. Heavy housework is not associated with reduced levels of being overweight and prospective studies are necessary to demonstrate an independent health benefit of participating in domestic activities.

Aged↗

Soil-transmitted nematode infections and mebendazole treatment in Mafia Island schoolchildren.

In August 2000, a cross-sectional study was performed to assess the prevalence and intensity of soil-transmitted nematode infections in schoolchildren on Mafia Island. Hookworm infection was widespread (72.5% prevalence) whereas Trichuris trichiura was less prevalent (39.7%) and Ascaris lumbricoides was present at a low prevalence (4.2%), mainly in urban areas. In a subsample of the study population, both Necator americanus and Ancylostoma duodenale were found, although N. americanus was more prevalent. This survey was followed by a parasitological evaluation of mebendazole treatment using a single, 500-mg dose. The data on outcome were used for comparison with those from recent studies of similar treatment regimens in the neighbouring island of Pemba, Zanzibar, where periodic chemotherapy with mebendazole to schoolchildren has been implemented as part of a helminth-control programme since 1994. A higher efficacy of mebendazole against hookworm infection was found in Mafia Island (where a cure 'rate' of 31.3% and an egg-reduction 'rate' of 78.1% were recorded) when compared with that observed in Pemba Island, possibly indicating that hookworms may be developing mebendazole resistance on Pemba Island as a result of intense exposure to the drug there.

Adolescent↗

Temporal evolution of the electric field accelerating electrons away from the auroral ionosphere.

The bright night-time aurorae that are visible to the unaided eye are caused by electrons accelerated towards Earth by an upward-pointing electric field. On adjacent geomagnetic field lines the reverse process occurs: a downward-pointing electric field accelerates electrons away from Earth. Such magnetic-field-aligned electric fields in the collisionless plasma above the auroral ionosphere have been predicted, but how they could be maintained is still a matter for debate. The spatial and temporal behaviour of the electric fields-a knowledge of which is crucial to an understanding of their nature-cannot be resolved uniquely by single satellite measurements. Here we report on the first observations by a formation of identically instrumented satellites crossing a beam of upward-accelerated electrons. The structure of the electric potential accelerating the beam grew in magnitude and width for about 200 s, accompanied by a widening of the downward-current sheet, with the total current remaining constant. The 200-s timescale suggests that the evacuation of the electrons from the ionosphere contributes to the formation of the downward-pointing magnetic-field-aligned electric fields. This evolution implies a growing load in the downward leg of the current circuit, which may affect the visible discrete aurorae.

Journal Article↗

A strategy for high throughput HLA-DQ typing.

We have developed a high throughput HLA typing methodology that is a modification of the standard sequence-specific primer method. This approach is distinct from other methods using an automated DNA analyzer, as more than one gene is typed in a single lane. We have optimized the method for use on an ABI 373 automated genotyping machine. Primers were designed to preferentially amplify DNA fragments of the generic allelic groups of the DQA1 and DQB1 loci. PCR products representing alleles at the DQA1 locus were amplified using a different fluorescent dye than the PCR products from the DQB1 locus. Only three PCR reactions are required for low resolution typing of DQA1 and DQB1. Use of different labeled primers enables genotyping for both loci in a single gel lane, allowing for 64 samples to be typed at low resolution for both DQA1 and DQB1 on a single gel. Automated allele assignments were determined based on DNA migration distance through a polyacrylamide gel using a standard genotype allele-calling program. Accuracy of this method is greater than 98% for both loci. The strategy described here may be adapted to include more loci or to produce higher resolution typing of alleles encoded by these loci. It can be readily optimized for use on other slab gel or capillary electrophoresis systems.

Alleles↗