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Biomedical subjects

A Vail

Publications and source records attributed to A Vail.

At least 37 records · Page 2Linked to original sources

Clomiphene or tamoxifen for idiopathic oligo/asthenospermia.

BACKGROUND: Oligo-astheno-teratospermia (sperm of low concentration, reduced motility and increased abnormal morphology) of unknown cause is common and the need for treatment is felt by patients and doctors alike. As a result, a variety of empirical, non-specific treatments have been used in an attempt to improve semen characteristics and fertility. The administration of anti-oestrogens is a common treatment because anti oestrogens interfere with the normal negative feedback of sex steroids at hypothalamic and pituitary levels in order to increase endogenous gonadotropin-releasing hormone secretion from the hypothalamus and FSH and LH secretion directly from the pituitary. In turn, FSH and LH stimulate Leydig cells in the testes, and this has been claimed to lead to increased local testosterone production, thereby boosting spermatogenesis with a possible improvement in fertility. There may also be a direct effect of anti-oestrogens on testicular spermatogenesis or steroidogenesis. This review considers the available evidence of the effect of both Clomiphene citrate and tamoxifen, both of which have a predominant anti-oestrogenic effect, for idiopathic oligo and/or asthenospermia. OBJECTIVES: The objective was to assess the effects of treating subfertile men with anti-oestrogens (clomiphene or tamoxifen) on pregnancy rates among couples where subfertility has been attributed to idiopathic oligo- and/or asthenospermia. SEARCH STRATEGY: The Cochrane Subfertility Review Group specialised register of controlled trials was searched". SELECTION CRITERIA: Randomised trials of anti-oestrogen therapy for 3 months or more compared to placebo or no placebo for subfertile males among couples where subfertility is attributed to male factor. DATA COLLECTION AND ANALYSIS: Data were extracted independently by two reviewers. Any differences were resolved with a third reviewer. MAIN RESULTS: Ten studies involving 738 men were included. Five of the trials did not specify method of randomisation. Anti-oestrogens had a positive effect on endocrinal outcomes, such as serum testosterone levels. In trials with secure randomisation there was no difference in the pregnancy rate between the anti-oestrogen groups and the control groups (odds ratio 1.26, 95% confidence interval 0.99 to 1.56). The overall pregnancy rate for these five trials was 15.4% compared to the spontaneous rate of 12.5% in the control groups. These odds increased to 1.56 (95% confidence interval 0.99 to 2.19) when all 10 trials were included, but this result is likely to be artificially inflated. REVIEWER'S CONCLUSIONS: Anti-oestrogens appear to have a beneficial effect on endocrinal outcomes, but there is not enough evidence to evaluate the use of anti-oestrogens for increasing the fertility of males with idiopathic oligo-asthenospermia.

Clomiphene↗

Bromocriptine for idiopathic oligo/asthenospermia.

BACKGROUND: Oligo-astheno-teratospermia (sperm of low concentration, reduced motility and increased abnormal morphology)of unknown cause is common and the need for treatment is felt by patients and doctors alike. As a result, a variety of empirical, non-specific treatments have been used in an attempt to improve semen characteristics and fertility. Whilst bromocriptine treatment for reducing prolactin levels in hyperprolactinaemic males (as in females), and, in the treatment of hypogonadotropic hypogonadism with hyperprolactinaemia, is beneficial, it has also been used for oligospermic men in the absence of any endocrinopathy. Prolactin may play a direct role in spermatogenesis and hormone production. It has also been claimed that in oligospermic men with normal gonadotrophins mean prolactin levels are higher and that hyperprolactinaemia is more common compared to fertile men. It has been proposed that the administration of bromocriptine under these circumstances might counteract a prolactin-induced block on the action of gonadotrophins on the testicles and, subsequently, that the reduction in prolactin levels might lead to an improvement in semen parameters and fertility. Although it is not licensed for use in male infertility, bromocriptine has been used for normogonadotrophic individuals with oligospermia and normal or sligthly elevated prolactin levels. This review considers the available evidence of the effect of bromocriptine therapy for normoprolactinaemic males with idiopathic oligo and/or asthenospermia. OBJECTIVES: The objective of this review was to assess the effects of bromocriptine on pregnancy rates among couples where subfertility has been attributed to idiopathic oligo- and/or asthenospermia. SEARCH STRATEGY: The Cochrane Subfertility Review Group specialised register of controlled trials was searched". SELECTION CRITERIA: Randomised trials of oral bromocriptine versus placebo or no treatment for couples with subfertility attributed to male factor. DATA COLLECTION AND ANALYSIS: Data were extracted by one reviewer and any disagreements were resolved by discussion with other reviewers. MAIN RESULTS: Four studies were included. The method of randomisation was not specified in any of the trials, which were all of crossover design. Compared with placebo, bromocriptine was associated with a significant reduction in serum prolactin levels (weighted mean difference -195.3 micro international units per litre, 95% confidence interval -276.5 to -114). No effects on sperm parameters were seen. There was also no effect on pregnancy rates observed between bromocriptine and placebo (0.70 odds ratio, 95% confidence interval 0.15 to 3.24). REVIEWER'S CONCLUSIONS: Bromocriptine appears to reduce prolactin levels in subfertile men with normal gonadotrophic function. There is not enough evidence to show that bromocriptine is helpful in improving fertility.

Bromocriptine↗

Kinin-enhancing drugs for unexplained subfertility in men.

BACKGROUND: Oligo-astheno-teratospermia (sperm of low concentration, reduced motility and increased abnormal morphology) of unknown cause is common and the need for treatment is felt by patients and doctors alike. As a result, a variety of empirical, non-specific treatments have been used in an attempt to improve semen characteristics and fertility. One suggested treatment for idiopathic oligo- and/or asthenospermia is the administration of kallikrein (kallidinogenase), a kinin-releasing enzyme (or kininogenase). The kinin biological system is complex and involves kininogen (the substrate), kininogenases (the activating enzymes), kinins (the effectors) and kininases (the inactivating enzymes). All four components of the kinin system have been found in the genitalia and in semen. Kallikrein releases 2 major kinins, kallidin and bradykinin, from seminal plasma kininogens. Activated kinins in semen affect sperm motility and metabolism. In vitro addition of kallikrein to semen has been shown to have a positive effect on sperm motility, sperm velocity, cervical mucus penetration, penetration of zona-free hamster eggs and post-thaw survival and motility rate after semen cryopreservation. The latter observation, however, was not confirmed in a more recent comparison of motility stimulants for cryopreserved semen using computerised sperm motion analysis. In vitro treatment of semen with kallikrein has been employed in a clinical context during sperm preparation prior to insemination. Although the kinin system may also be involved in the regulation of spermatogenesis in vivo, a clear mechanism of action is missing. Multiple suggestions on how an increase in kinin levels in the genital tract influences spermatogenesis at the testicular levels have been made by various authors. OBJECTIVES: To determine whether treatment of the male with drugs enhancing kinin levles increases pregnancy rates among couples where failure to conceive has been attributed to idiopathic oligo- and/or asthenospermia. Effects on sperm parameters and sex hormones were studied as secondary outcomes. SEARCH STRATEGY: The Cochrane Subfertility Review Group specialised register of controlled trials was searched". SELECTION CRITERIA: SIxteen RCTs on the therapeutic use of androgens (clomiphene citrate or tamoxifen) in subfertile men were identified. Six trials were excluded. DATA COLLECTION AND ANALYSIS: Methodological characteristics of trials Baseline characteristics of the studied groups Outcomes: Pregnancy rates, semen parameters (sperm concentration, motility and morphology), endocrinology (serum FSH, testosterone and oestradiol)

Fertility Agents, Male↗

Barrier agents for preventing adhesions after surgery for subfertility.

BACKGROUND: Pelvic adhesions can be the result of inflamation, endometriosis or surgical trauma. Prevention of postoperative adhesions (either new or reoccurance) has been postulated by using barriers to prevent two surfaces being in contact. When pelvic surgery is being undertaken strategies to reduce pelvic adhesions occurring may be undertaken and these include barrier agents which are placed between the pelvic structures. Two synthetic barriers with differential characteristics are commercially available: oxidised regenerated cellulose (Interceed) and polytetrafluoroethylene (PTFC) (GoreTex). OBJECTIVES: The objective of this review was to assess the effect of mechanical barriers (materials interposed between pelvic structures to prevent adherence of serosal surfaces) used during pelvic surgery in women of reproductive age on pregnancy rates, pelvic pain, or postoperative adhesion reformation. SEARCH STRATEGY: The Cochrane Menstrual Disorders and Subfertility Group specialised register of controlled clinical trials was undertaken. In addition, companies were contacted for unpublished trials. SELECTION CRITERIA: Randomised controlled trials or controlled clinical trials of barriers versus no treatment or other barriers in women undergoing fertility preserving pelvic surgery. DATA COLLECTION AND ANALYSIS: Reviewers assessed eligibility and trial quality. MAIN RESULTS: 15 randomised controlled trials were included. Five trials randomised patients while the remainder randomised pelvic organs. Laparoscopy was the primary surgical technique in six trials while the remaining trials were laparotomy. Indications for surgery included myomectomy (five trials), ovarian surgery (four trials), pelvic adhesions (six trials), endometriosis (two trials) and mixed (one trial). Thirteen trials assessed Interceed versus no treatment, two assessed Interceed versus Gore-Tex, one trial assessed Gore-Tex versus no treatment, and one trial assessed Seprafilm versus no treatment. No study reported pregnancy or reduction in pain as an outcome. The use of Interceed in women was associated with reduced incidence of pelvic adhesion formation, both new formation and re-formation following laparoscopic surgery and after laparotomy. Gore-Tex was more effective than no barrier or Interceed in preventing adhesion formation. There was limited evidence that Seprafilm was effective in preventing adhesion formation in women following myomectomy. REVIEWER'S CONCLUSIONS: The absorbable adhesion barrier Interceed reduces the incidence of adhesion formation, both new formation and re-formation, at laparoscopy and laparotomy, but there are insufficient data to support its use to improve pregnancy rates. Gore-Tex may be superior to Interceed in preventing adhesion formation but its usefulness is limited by the need for suturing and later removal. There was no evidence of effectiveness of Seprafilm in preventing adhesion formation.

Cellulose, Oxidized↗

Effective treatment of subfertility: introducing the Cochrane Menstrual Disorders and Subfertility Group.

The last two decades have seen a rapid explosion in research surrounding subfertility treatments. This ever-increasing volume of research has made it a difficult task for health professionals involved in the management of the subfertility to be able to assimilate the information easily. There is an urgent need for the findings from research to be synthesized into simple easy to read reviews that are both of a high quality and are based on the best evidence available. The Menstrual Disorders and Subfertility Group of the Cochrane Collaboration is attempting to address these issues by collecting a register of all the randomized controlled trials in the field of reproductive medicine and preparing systematic reviews on topics that will be of interest to healthcare workers and consumers. Readers are invited to participate in this process by identifying published and unpublished data and by helping in the process of preparing protocols and systematic reviews for inclusion in the Cochrane Library.

Female↗

Clinical interventions and outcomes of One-to-One midwifery practice.

BACKGROUND: Changing Childbirth became policy for the maternity services in England in 1994 and remains policy. One-to-One midwifery was implemented to achieve the targets set. It was the first time such a service had been implemented in the Health Service. An evaluation was undertaken to compare its performance with conventional maternity care. METHODS: This was a prospective comparative study of women receiving One-to-One care and women receiving the system of care that One-to-One replaced (conventional care) to compare achievement of continuity of carer and clinical outcomes. The evaluation took place in The Hammersmith Hospitals NHS Trust, the Queen Charlotte's and Hammersmith Hospitals. This was part of a larger study, which included the evaluation of women's responses, cost implications, and clinical standards and staff reactions. The participants were all those receiving One-to-One midwifery practice (728 women), which was confined to two postal districts, and all women receiving care in the system that One-to-One replaced, in two adjacent postal districts (675 women), and expecting to give birth between 15 August 1994 and 14 August 1995. Main outcome measures were achievement of continuity of care, rates of interventions in labour, length of labour, maternal and infant morbidity, and breastfeeding rates. RESULTS: A high degree of continuity was achieved through the whole process of maternity care. One-to-One women saw fewer staff at each stage of their care, knew more of the staff who they did see, and had a high level of constant support in labour. One-to-One practice was associated with a significant reduction in the use of epidural anaesthesia (odds ratio (OR) 95 per cent confidence interval (CI) = 0.59 (0.44, 0.80)), with lower rates of episiotomy and perineal lacerations (OR 95 per cent CI = 0.70 (0.50, 0.98)), and with shorter second stage labour (median 40 min vs 48 min). There were no statistically significant differences in operative and assisted delivery or breastfeeding rates. CONCLUSIONS: This study confirms that One-to-One midwifery practice can provide a high degree of continuity of carer, and is associated with a reduction in the rate of a number of interventions, without compromising safety of care. It should be extended locally and replicated in other services under continuing evaluation.

Adult↗

Experiences of a biostatistician on a U.K. Research Ethics Committee.

Poorly planned research liable to produce misleading results is unethical. Local Research Ethics Committees in the U.K. have a duty to assess the scientific merit of studies, of which statistical aspects are an essential component, yet few have access to a biostatistician. I present personal experience of the workload involved and general issues arising in submissions to a large teaching NHS Hospitals Trust, with emphasis on sample size. These general issues should apply to analogous committees in countries other than the U.K. The opportunity to influence the quality of all local medical research is argued to be reasonable incentive for more voluntary involvement by statisticians.

Bioethics↗

Toxicity and dosimetry of fractionated total body irradiation prior to allogeneic bone marrow transplantation using a straightforward radiotherapy technique.

Since 1989, we have used a relatively straightforward technique for giving total body irradiation (TBI), using anterior and posterior parallel opposed fields with the arms and fists acting as compensators. The dosimetry, toxicity and outcome of 48 patients (26 adults, 22 children) treated with TBI using this technique have been audited. A dose of 14.4 Gy in eight fractions over 4 days was prescribed to all patients with an unrelated donor and 12 Gy in six fractions over 3 days to those with a sibling donor. From May 1994, all children received 14.4 Gy because of a recommendation from the United Kingdom Children's Cancer Study Group. The range of lung dosimetry was -6% to +7% when the dose was specified to the lung maximum. The trunk doses were all within +/-10% of the prescribed dose. Doses to other regions of the body were less homogeneous but clinically acceptable in that the minimum doses were never less than -10% of the prescribed dose. Mucositis was the most common side effect; its treatment with opioids was more frequent after 14.4 Gy than after 12 Gy (P=0.0004) and in adults than in children (P=0.01). No cataracts have yet been seen in these patients. The radiation was not found to be a proven cause of clinical pneumonitis, although there was one death due to interstitial pneumonitis, which was likely to have been caused by cytomegalovirus infection in which radiation pneumonitis could not be excluded. There were no other suspected TBI-related deaths. In conclusion, this straightforward technique achieved acceptable dosimetry and was well tolerated.

Abdomen↗

The sugar-fat relationship revisited: differences in consumption between men and women of varying BMI.

OBJECTIVE: To assess the relationship of dietary fat and sugar consumption in men and women with different body mass indices (BMI). To determine the actual food sources for sugar intake, comparing differences between men and women across BMI groups. The effect of excluding individuals with low energy intakes (that is, invalid data) on these relationships was also incorporated in the analysis. SUBJECTS: Subjects for this analysis were those individuals who participated in the 1986-1987 Dietary and Nutrition Survey of British Adults (DNSBA). METHOD: In the DNSBA, dietary intake was assessed using seven-day weighed food records, providing estimates of dietary fat and sugar intake. From the DNSBA database food records, sources of sugar intake were classified into five sugar containing food groups (high fat sweet products, fruits, dairy products, sugar products (excluding soft drinks) and sugar products (including soft drinks)). BMI was calculated from the measurement of height and body weight. RESULT: A positive relationship between BMI and dietary fat intake was found for men, both when fat was expressed as a percentage of energy and in absolute terms (g/d). This relationship was only replicated for women when intake was expressed in absolute terms. A negative relationship was found between sugar intake (as a percentage of energy) and BMI in men, but not women. Expressing sugar consumption in absolute terms did not produce a statistically significant relationship with BMI for either men or women. In women the only sugar source associated with BMI was high fat sweet products (for example, cakes, biscuits, chocolate), where higher intakes were related to higher BMIs. The reverse relationship was found for men. In men, BMI was also negatively related to the intake of sugar products (for example, table sugar, preserves, sugar confectionery), both when soft drinks were included and excluded. The inclusion of low energy reporters (LER) in the analysis altered the relationships between nutrients and BMI, particularly among women. The association between overall fat intake (g/d) and BMI was weakened, while the negative relationship with sugar intake was strengthened. In the case of women, the inclusion of LER completely reversed the relationship between consumption of high fat sweet foods (cakes, biscuits, chocolate) and BMI (due to the reduced reporting of these products by obese women). Fewer alterations in the relationships between BMI and the sources of sugar consumed were observed in men than in women when LER were included in the analysis. CONCLUSION: The relationships between dietary fat, sugar and BMI are different in men and women, and are dependent on the inclusion of LER, particularly in women. The results suggest that among women the consumption of high fat sweet products may be a factor in understanding obesity. Furthermore, the observation of high consumption of these foods among obese women is consistent with measured preferences for these high fat sweet foods. The altered representation of the data created by LER appears to distort the relationship between sugar, fat and the degree of obesity in men and women.

Adult↗

The use of clinical audit in evaluating maternity services reform: a critical reflection.

The clinical evaluation described here, using a casenote study, was part of a larger study evaluating the changes made to part of the maternity services in one NHS Trust, in response to the recommendations of Changing Childbirth (Department of Health 1993a). Results of the audit showed no evidence of a lowering of clinical standards within the study group and provided reassurance that a radical change in the model of care, with greatly enhanced continuity of career, an emphasis on community-based and midwifery-led care, and some reductions in labour interventions, could be implemented without compromising safety of care. The audit process raised a number of methodological problems which will need to be addressed in developing audit approaches which are able to reflect quality of care. It is important to recognize that the record of care is not a direct mirror of the care provided but a secondary source, kept for different purposes and designed to cover a different set of priorities from those which audit may seek to capture. The audit approach used in this study will be modified in continuing evaluation of the service as it moves from a pilot stage towards providing a mainstream service. Additional methods, including direct observation of care, will be employed in a sample of cases in order to assist in interpretation of audit findings.

Continuity of Patient Care↗

Evaluation of one-to-one midwifery: women's responses to care.

BACKGROUND: One-to-one midwifery was a demonstration project introduced into a London-based maternity service in 1993 to put into practice the new government policy for maternity services in England. Evaluation was integral to the development of the project. METHODS: The evaluation of women's responses was conducted between August 1994 and August 1995 based on a longitudinal, self-completion questionnaire, interviews, and focus groups. Women in the study group (n = 728) received the new service and women in the control group (n = 675) received conventional care. The study design integrated quantitative and qualitative methods and went beyond a simple estimation of satisfaction with care. RESULTS: Satisfaction with antenatal and birth care was generally high, but study group women showed more positive responses overall. Both groups showed a preference for continuity of caregiver, but expectations were higher in the study group (72% of the study group and 42% of the control group preferred to see one caregiver). Both groups had less satisfied responses to hospital postnatal care (50% study and 54% control group were very satisfied). Study group women showed greater preparedness for birth than control group women (18% vs 12% "very well prepared") and for the time after the baby's birth (26% vs 15% "very prepared"). CONCLUSIONS: The study demonstrated that women were more satisfied with the one-to-one model of care. Taken together with the results of clinical and economic audit and professional responses, the evaluation suggests that this model should be developed and evaluated further to gain a greater understanding of women's needs of the maternity service.

Adult↗

Randomised, controlled trial of spirometric changes in elderly people receiving timolol or betaxolol as initial treatment for glaucoma.

AIM: To investigate respiratory and cardiovascular side effects in elderly people in the first 12 months after commencing topical beta antagonists. METHODS: 40 patients (mean age 74 years) were recruited to a randomised, masked study. Spirometry, pulse, and blood pressure were recorded before, 1 month, and 12 months after starting topical therapy with either timolol 0.5% twice daily or betaxolol 0.5% twice daily. RESULTS: After 1 month five of 20 patients allocated timolol and three of 20 given betaxolol had discontinued it for respiratory reasons, not always accompanied by symptoms. There were no significant differences in changes in mean values of spirometry, pulse, or blood pressure between groups. No further changes were made in therapy for respiratory reasons in the following year. One patient suffered a hypotensive stroke within 2 days of starting timolol. CONCLUSIONS: By performing spirometry before starting topical beta antagonist therapy and repeating it after 1 month most patients at risk of respiratory impairment can be identified.

Aged↗

Case-control study of breast cancer in south east England: nutritional factors.

OBJECTIVES: To explore dietary risk factors, in particular fat intake, for breast cancer, using an approach to reduce recall bias of subjects and so provide a more reliable estimate of dietary intake than previous similar studies. DESIGN: A case-control study of women aged 50-65 years attending the breast assessment clinics of the breast screening programme in Southampton and Portsmouth, southern England. Data were analysed for all women requiring further clinical procedures; all women recalled to have an early rescreen; and a random sample of women found to be normal and referred for a routine rescreening appointment (standard recall). MEASUREMENTS: An interview obtained information on various lifestyle characteristics including smoking and alcohol intake, weight, waist, and hip measurements were also taken at the clinic. Women were given a detailed questionnaire on food intake to complete at home and return by post. RESULTS: 1577 women were included in the study: 220 with breast cancer (cases); 179 with benign breast disease; 353 early rescreen and 825 given a standard recall appointment. There were few differences in nutritional intake between the four groups. Logistic regression analyses were carried out comparing the dietary intake of cases with that of each control group adjusting for important demographic and reproductive factors. Results for the case and standard recall comparison are presented. The only non-calorific nutrient to reach significance was iron, which was negatively associated with risk (p = 0.03). For fat intake, the odds decreased with increasing polyunsaturated fat (p = 0.15), showed no trend with monounsaturated fat (p = 0.37) and increased (p = 0.10) with increasing saturated fat. No pattern was clear for the other calorie providing nutrients. CONCLUSIONS: In line with recent cohort studies, this study has shown no evidence to support the hypothesis that dietary fat is an important contributor to breast cancer rates. Biases should have been reduced by studying subjects from the screening programme who were at an early stage of disease.

Aged↗

The prevalence of multiple sclerosis in the Leeds Health Authority.

OBJECTIVES: To determine the prevalence of multiple sclerosis in the Leeds Health District. METHODS: Multiple sources of case ascertainment were used-namely, neurology departments, hospital episode statistics, general practitioners, the Leeds branch of the Multiple Sclerosis Society, the West Yorkshire Multiple Sclerosis Therapy Centre, community physiotherapists and occupational therapists, the Leeds Wheelchair Centre, and the Young Disabled Unit. Data collection was from retrospective analysis of hospital and primary care case records. A population based incidence register was established by prospectively registering all new patients with diagnoses of multiple sclerosis. RESULTS: On prevalence day, 30 April 1996, 712 people with multiple sclerosis were identified living in Leeds (population 732,061), giving a prevalence of 97/10(5). The prevalence for definite and probable multiple sclerosis was 84/10(5), and for suspected multiple sclerosis it was 13/10(5). The sex ratio of prevalent people with multiple sclerosis was 2.79 to 1 women to men. The mean age of prevalent cases was 51 years, the mean age at symptom onset was 34 years, and the mean duration of disease was 16 years. Forty cases were prospectively reported as incident cases from 1 November 1995 to 1 February 1996. CONCLUSIONS: The prevalence of multiple sclerosis in Leeds was found to be similar to that in the south of the United Kingdom but lower than that in Scotland. There is no evidence of a latitudinal gradient of increasing prevalence of multiple sclerosis from the south to the north of England.

Adult↗

Statistical methods in epidemiology. II: A commonsense approach to sample size estimation.

PURPOSE: It has been argued, by many, that mathematical formulae for estimating sample size are unnecessarily complex, so much so that researchers may be reluctant to seek statistical advice. METHOD: This paper reviews methods of sample size estimation arguing that two formulae (one based on comparison of proportion of 'successes', the other based on comparison of means of normally distributed data) suffice for many situations. This paper argues the case by taking examples drawn mainly from clinical trials research. However, the methods outlined can also be used in epidemiology specifically in both case-control and cohort studies with no loss of information. RESULTS: For the situations outlined, worked examples are provided. CONCLUSIONS: Sample size estimation need not necessarily be a complex process. Simple techniques exist which enable the clinician and the statistician to work together. Continued dialogue between both parties is required so that good ideas do not go to waste.

Data Interpretation, Statistical↗

Applicants to medical school: the value of predicted school leaving grades.

Among school leavers applying to study medicine in the United Kingdom a majority offer General Certificate of Education, Advanced Level (A-level) examinations as part of the assessment of academic ability. At the time of application, up to 9 months before completing A-level studies, schools are requested to predict the final grades likely to be achieved by the applicant. A total of 5054 A-level predictions from 1661 applicants to a single medical school were compared with the results achieved. Predicted and achieved grades were both high with 93% of predicted grades being A or B. Over half the predictions were correct, with 41% of predictions above achieved grades and only 7% below achieved grade. Independent and selective schools predicted higher grades than comprehensive schools and sixth form colleges, and their pupils were more likely to achieve the entrance requirements. A-level predictions for medical school applicants are a strong predictor of achievement and should continue to be regarded as a useful part of the selection process.

Adolescent↗

Conclusions of the corneal transplant follow up study. Collaborating Surgeons.

AIM: On the basis of finalised data from the Corneal Transplant Follow up Study to identify and quantify factors influencing corneal graft outcome in terms of graft survival, rejection, visual acuity, and astigmatism. METHODS: Multifactorial analysis of 2777 grafts registered by the UK Transplant Support Service from July 1987 to June 1991. RESULTS: Several recipient factors influencing graft survival, rejection, and visual acuity were identified, but no donor factors. Of the operative factors amenable to change, mixed suturing was associated with reduced graft survival, and larger grafts with increased risk of rejection but better visual acuity when surviving. There was increased risk of rejection with poor matching at HLA class I antigens, but mismatched HLA-DR grafts suffered less rejection than those with zero HLA-DR mismatches. Recipient age below 10 years was associated with increased risk of both rejection and graft failure. However, whereas increasing age above 10 years was not associated with differential graft survival, it was significantly associated with decreasing risk of rejection. CONCLUSIONS: While confirming possible benefits of HLA-A and B matching, the expense and delay involved in awaiting matched HLA-DR tissue is unlikely to be justified. Other donor factors are unrelated to graft outcome following screening of tissue by eye banks. The highest rates of graft failure and rejection happen in the early postoperative period, and factors influencing visual outcome are also apparent at this stage.

Adolescent↗