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Biomedical subjects

S Kenyon

Publications and source records attributed to S Kenyon.

At least 19 recordsLinked to original sources

Participating in a trial in a critical situation: a qualitative study in pregnancy.

BACKGROUND: Randomised controlled trials of interventions in critical situations are necessary to establish safety and evaluate outcomes. Pregnant women have been identified as a potentially vulnerable population. OBJECTIVE: To explore women's experiences of being recruited to ORACLE, a randomised controlled trial of antibiotics in pre-term labour. METHODS: Twenty qualitative interviews were conducted with women who had participated in ORACLE. Analysis was based on the constant comparative method. RESULTS: Women gave prominence to the socioemotional aspects of their interactions with healthcare professionals in making decisions on trial participation. Comments on the quality of written and spoken information were generally favourable, but women's accounts suggest that the stressful nature of the situation affected their ability to absorb the information. Women generally had poor understanding of trial design and practices. The main motivation for trial participation was the possibility of an improved outcome for the baby. The second and less prominent motivation was the opportunity to help others, but this was conditional on there being no risks associated with trial participation. In judging the risks of participation, women seemed to draw on "common sense" understandings including a perception that antibiotics were risk free. DISCUSSION: Recruitment to trials in critical situations raises important questions. Future studies should explore how rigorous governance arrangements for trials, particularly in critical situations, can protect participants rather than relying on ideals of informed consent that may be impossible to achieve. Future research should include a focus on interactions between research candidates and professionals involved in recruitment.

Antibiotic Prophylaxis↗

The passage of trimethylamine across rat and human skin.

Trimethylamine is a volatile low molecular weight tertiary aliphatic amine that has known toxicity and the potential for human exposure from industrial and environmental sources is considerable. It is generally believed that absorption across the skin is an unimportant route of entry but there is little, if any, supporting evidence for this assumption. Passage across rat and human skin has been investigated employing excised skin circles in an in vitro diffusion cell apparatus. Trimethylamine was found to penetrate readily when applied to the epidermal surface of skin at three different dose levels (0.1, 1.0 and 10 mg per skin membrane 0.32 cm2). The apparent dermal flux was calculated as 3.40 +/- 1.60, 58.3 +/- 30.6 and 265.0 +/- 155.0 microg/cm2/h for rat and 0.98 +/- 0.75, 9.21 +/- 3.06 and 92.7 +/- 31.9 microg/cm2/h for human at the three dose levels, respectively. Both rat and human skin was able to act as a reservoir, with the trimethylamine not remaining in the stratum corneum but passing through. When presented to the underneath of rat and human skin circles, both [U-14C]-trimethylamine and [U-14C]-trimethylamine N-oxide were able to pass from the dermis to the epidermis. Small but detectable amounts of trimethylamine were oxidised to its N-oxide during passage through the skin.

Animals↗

In vitro predictions of skin absorption of caffeine, testosterone, and benzoic acid: a multi-centre comparison study.

To obtain better insight into the robustness of in vitro percutaneous absorption methodology, the intra- and inter-laboratory variation in this type of study was investigated in 10 European laboratories. To this purpose, the in vitro absorption of three compounds through human skin (9 laboratories) and rat skin (1 laboratory) was determined. The test materials were benzoic acid, caffeine, and testosterone, representing a range of different physico-chemical properties. All laboratories performed their studies according to a detailed protocol in which all experimental details were described and each laboratory performed at least three independent experiments for each test chemical. All laboratories assigned the absorption of benzoic acid through human skin, the highest ranking of the three compounds (overall mean flux of 16.54+/-11.87 microg/cm(2)/h). The absorption of caffeine and testosterone through human skin was similar, having overall mean maximum absorption rates of 2.24+/-1.43 microg/cm(2)/h and 1.63+/-1.94 microg/cm(2)/h, respectively. In 7 out of 9 laboratories, the maximum absorption rates of caffeine were ranked higher than testosterone. No differences were observed between the mean absorption through human skin and the one rat study for benzoic acid and testosterone. For caffeine the maximum absorption rate and the total penetration through rat skin were clearly higher than the mean value for human skin. When evaluating all data, it appeared that no consistent relation existed between the diffusion cell type and the absorption of the test compounds. Skin thickness only slightly influenced the absorption of benzoic acid and caffeine. In contrast, the maximum absorption rate of testosterone was clearly higher in the laboratories using thin, dermatomed skin membranes. Testosterone is the most lipophilic compound and showed also a higher presence in the skin membrane after 24 h than the two other compounds. The results of this study indicate that the in vitro methodology for assessing skin absorption is relatively robust. A major effort was made to standardize the study performance, but, unlike in a formal validation study, not all variables were controlled. The variation observed may be largely attributed to human variability in dermal absorption and the skin source. For the most lipophilic compound, testosterone, skin thickness proved to be a critical variable.

Adolescent↗

Women's accounts of consenting to surgery: is consent a quality problem?

BACKGROUND: Consent has been placed at the centre of doctor-patient relationships. Attempts to improve the consent process in medicine have drawn on bioethical and legal traditions. Current approaches to consent emphasise the provision of information and have, in the UK, resulted in a single standardised format and process for both elective and emergency situations. Investigation of patients' perceptions and priorities are important in understanding the quality of the consent process. METHODS: In this qualitative study, semi-structured interviews were conducted with 25 women. Eleven had elective and 14 had emergency operations in obstetrics and gynaecology. All interviews were recorded and transcribed verbatim. Data analysis was based on the constant comparative method. RESULTS: Participants' perceptions of surgery strongly influenced the meanings they gave to consent. Some, particularly those undergoing elective operations, wanted surgery. Others were uncertain of their desire for surgery or felt that it was imposed on them. Consenting was interpreted as a ritualistic legal procedure. There was an overwhelming tendency to view consent as not primarily serving patients' needs, although some advantages of the consent process were identified. Accounts made no reference to ethics. CONCLUSION: Countering paternalism will remain difficult to achieve if issues surrounding consent continue to be debated between professionals without due effort to reflect patients' own views and values and to appreciate the circumstances under which consent is sought.

Adult↗

ORACLE--antibiotics for preterm prelabour rupture of the membranes: short-term and long-term outcomes.

UNLABELLED: Preterm prelabour rupture of the foetal membranes (pPROM) is the most common antecedent of preterm birth and can lead to death, neonatal disease and long-term disability. Previous small trials of antibiotics for pPROM suggested some health benefits for the neonate, but the results were inconclusive. A large, randomized, multicentre trial was undertaken to try to resolve this issue. In total, 4826 women with pPROM were randomized to one of four treatments: 325 mg co-amoxiclav plus 250 mg erythromycin, co-amoxiclav plus erythromycin placebo, erythromycin plus co-amoxiclav placebo, or co-amoxiclav placebo plus erythromycin placebo, four times daily for 10 d or until delivery. The primary outcome measure was a composite of neonatal death, chronic lung disease or major cerebral abnormality on ultrasonography before discharge from hospital. The analysis was undertaken by intention to treat. Indications of short-term respiratory function, chronic lung disease and major neonatal cerebral abnormality were reduced with the prescription of erythromycin. In contrast, the use of co-amoxiclav was associated with a significant increase in the occurrence of neonatal necrotizing enterocolitis. CONCLUSION: Prophylactic antibiotics can play a role in preterm prelabour rupture of the membranes in reducing infant morbidity.

Adult↗

Antibiotics for preterm premature rupture of membranes.

OBJECTIVES: The aim of the review was to evaluate the effectiveness and the immediate and long-term safety of the effects of administering antibiotics to women with preterm prelabour rupture of membranes on maternal infectious morbidity, fetal and neonatal morbidity and mortality, and longer term childhood development. SEARCH STRATEGY: All randomized trials identified using the search strategy described by the Cochrane Pregnancy and Childbirth Group. SELECTION CRITERIA: All trials which reported clinically relevant outcomes (as opposed to laboratory data) were included. DATA COLLECTION AND ANALYSIS: Data were extracted from each report without any blinding of either the results or the treatments which women received. Unpublished data were sought from a number of authors. MAIN RESULTS: Antibiotic treatment following pPROM is effective at prolonging pregnancy and reducing maternal and neonatal infectious morbidity. There is no statisically proven benefit that their use improves neonatal mortality and morbidity in the short or long term. REVIEWER'S CONCLUSIONS: There are insufficient data to recommend routine prescription of antibiotics in this clinical situation. Research into this area should continue.

Anti-Bacterial Agents↗

The ORACLE trial.

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Anti-Bacterial Agents↗