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Biomedical subjects

J Hewison

Publications and source records attributed to J Hewison.

At least 55 records · Page 3Linked to original sources
PubMed1997

Screening for fragile X syndrome.

BACKGROUND AND AIM OF REVIEW. In 1991, the gene responsible for fragile X syndrome, a common cause of learning disability, was discovered. As a result, diagnosis of the disorder has improved and its molecular genetics are now understood. This report seems to provide the information needed to decide whether to use DNA testing to screen for the disorder. HOW THE RESEARCH WAS CONDUCTED. A literature search of electronic reference databases of published and 'grey' literature was undertaken together with hand searching of the most recent publications. RESEARCH FINDINGS. NATURAL HISTORY. Physical characteristics of fragile X syndrome include facial atypia, joint laxity and, in boys, macro-orchidism. Most affected males have moderate-to-severe learning disabilities with IQs under 50 whereas most females have borderline IQs of 70-85. Behavioural problems are similar to those seen with autism and attention-deficit disorders. Although fragile X syndrome is not curable there are a number of medical, educational, psychological and social interventions that can improve the symptoms. About 6% of those with learning disabilities tested in institutions have fragile X syndrome. Population prevalence figures are 1 in 4000 in males and 1 in 8000 in females. GENETICS. The disorder is caused by a mutation in a gene on the X chromosome which includes a trinucleotide repeat sequence. The mutation is characterized by hyper-expansion of the repeat sequence leading to down-regulation of the gene. In males an allele with repeat size in excess of 200, termed a full mutation (FM), is always associated with the affected phenotype, whereas in females only half are affected. Individuals with alleles having repeat size in the range 55-199 are unaffected but in females the sequence is heritably unstable so that it is at high risk of expansion to an FM in her offspring. This allele is known as a pre-mutation (PM) to contrast it with the FM found in the affected individual. No spontaneous expansions directly from a normal allele to an FM have been observed. SCREENING STRATEGIES. The principal aims of screenng for fragile X syndrome is to reduce the birth prevalence of the disorder, by prenatal diagnosis and selective termination of pregnancy, or by reducing the number of pregnancies in women who have the FM or PM alleles. Possible screening strategies are: routine antenatal testing of apparently low risk pregnancies, preconceptual testing of young women, and systematic testing in affected families ('cascade' screening). A secondary aim is to bring forward the diagnosis of affected individuals so that they might benefit from early treatment. Active paediatric screening and neonatal screening could achieve this but there is no direct evidence of any great benefit from early diagnosis. SCREENING TESTS. Cytogenetic methods are unsuitable for screening purposes. Southern blotting of genomic DNA can be used but is inaccurate in measuring the size of small PMs, there is a long laboratory turnaround time, and it is relatively expensive. The best protocol is to amplify the DNA using polymerase chain reaction on all samples, and when there is a possible failure to amplify, a Southern blot.(ABSTRACT TRUNCATED)

Costs and Cost Analysis↗
PubMed1996

The Diabetes Health Profile (DHP): a new instrument for assessing the psychosocial profile of insulin requiring patients--development and psychometric evaluation.

The aim of the studies was to evaluate the psychometric properties and construct validity of the Diabetes Health Profile (DHP-1). Content for the DHP-1 was derived following in-depth interviews with 25 insulin dependent and insulin requiring patients, a review of the literature and discussions with health care professionals. Initial analysis of the factor structure of the DHP-1 was carried out on the responses of 239 insulin dependent and insulin requiring patients, with a mean age of 40.85 years (SD = 13.0), resulting in a 43 item three factor solution. The 43 item version of the DHP-1 was completed by 2,239 insulin dependent/requiring patients (mean age = 39.8, SD = 10) years. Fifty-one per cent were men. A forced three factor Principal Factoring Analysis with varimax rotation was carried out. Eleven items were excluded with item factor cross loadings > 0.30 or item factor loadings < 0.30. PAF analysis of the 32 items resulted in a three factor solution accounting for 33% of the total explained variance. The three factors were interpreted as Psychological Distress, Barriers to Activity and Disinhibited Eating. Factor congruence between subsamples were: Psychological distress (0.93), Barriers to Activity (0.93) and Disinhibited Eating (0.99). Coefficients of congruence between men and women were 0.94, 0.92 and 0.99 for Psychological Distress, Barriers to Activity and Disinhibited Eating respectively. Internal consistency of the three factors (Cronbach's alpha) were: Psychological Distress (0.86), Barriers to Activity (0.82), and Disinhibited Eating (0.77). Construct-convergent validity was investigated on a sample of 233 insulin dependent and insulin requiring patients (mean age = 51.46 years). Psychological Distress and Barriers to Activity subscales correlated with the Hospital Depression and Anxiety Scale = 0.50 to 0.62, p < 0.01) and subscales of the SF-36 (range: r = -0.17 to -0.62, p < 0.01). These findings lend support to the construct validity and reliability of the DHP-1 and that it is suitable for further development.

Adult↗
PubMed1996

An Ethiopian birth cohort study.

A one-year birth cohort was studied in Jimma town, South West Ethiopia, in 1992-93. We report here on the design and on the methods used in the study and describe the principal health outcomes. Infants were visited bimonthly until their first birthday. Background data on the physical, cultural and economic environment of the home were collected at the first visit, and data on nursing and weaning on traditional surgical and other practices, and on vaccination at the first visit and at each subsequent visit. Length, weight and mid upper arm circumference were measured, and details of the mother's handling of illness episodes recorded. Of 1563 children born, 86% were successfully followed to the end of their first year or to an earlier death. There were 141 deaths, indicating an infant mortality of 115/1000 (estimated probability of surviving to 1 year 0.8851, with s.e. 0.0101). The mean length and weight of the singleton infants at the end of their first year was -1.41 and -1.52 SD from the median of the NCHS/WHO reference population. Weights throughout the first year were analysed in more detail using a Reed model, fitted as a random coefficient regression model in ML3-E. There were clear differences in growth across the different ethnic groups, with the best growing group weighing on average about 1 kg more at the end of the first year than the groups growing least well.

Chi-Square Distribution↗
PubMed1995

A randomised trial of three methods of giving information about prenatal testing.

OBJECTIVE: To test the effect of extra non-directive information about prenatal testing, given individually or in a class. SETTING: Antenatal clinics in a district general hospital and a university hospital. DESIGN: Randomised controlled trial; participants allocated to control group or offer of extra information individually or in class. SUBJECTS: 1691 women booking antenatal care before 15 weeks' gestation. INTERVENTIONS: All participants received the usual information about prenatal tests from hospital staff. Individual participants were offered a separate session with a research midwife in which prenatal screening was described in detail. Class participants were offered the same extra information in an early prenatal class. MAIN OUTCOME MEASURES: Attendance at extra information sessions; uptake rates of prenatal tests; levels of anxiety, understanding, and satisfaction with decisions. RESULTS: Attendance at classes was lower than at individual sessions (adjusted odds ratio 0.45; 95% confidence interval 0.35 to 0.58). Ultrasonography was almost universally accepted (99%) and was not affected by either intervention. Uptake of cystic fibrosis testing, high in controls (79%), was lowered in the individual group (0.44; 0.20 to 0.97) and classes (0.39; 0.18 to 0.86). Uptake of screening for Down's syndrome, already low (34%) in controls, was not further depressed by extra information in classes (0.99; 0.70 to 1.39) and was slightly higher in the individual group (1.45; 1.04 to 2.02). Women offered extra information had improved understanding and were more satisfied with information received; satisfaction with decisions about prenatal testing was unchanged. The offer of individual information reduced anxiety later in pregnancy. CONCLUSIONS: Ultrasonography is valued for non-medical reasons and chosen even by fully informed people who eschew prenatal diagnosis. The offer of extra information has no overall adverse effects on anxiety and reduces uptake of blood tests when background uptake rate is high (but not when it is already low). High uptake of prenatal blood tests suggests compliant behaviour and need for more information.

Anxiety↗
PubMed1995

Developing outcome measures for ambulatory care--an application to asthma and diabetes.

Increasing emphasis is now being placed on the assessment of patient outcomes, both in evaluating medical interventions and in quality assurance initiatives. Clinicians, purchasers, managers and researchers need outcome measures that are valid, reliable and responsive. This paper describes the theory and practice underlying the development of outcome measures for two chronic conditions, asthma and diabetes, for application in ambulatory settings. Existing generic and condition-specific health status and health-related quality-of-life measures were administered to almost 1300 patients. The psychometric properties of these measures were examined to identify those that were of adequate validity and reliability in these population groups. Step-wise regression procedures were then used to identify a core set of scales that best predicted patients' general health perceptions, which could be used in measuring general health outcomes for each of these groups. These core sets consist of up to 40 items, spanning physical function, energy and vitality, emotional well-being and condition-specific aspects of health such as symptom control. Further analysis is being carried out to assess the responsiveness to change of these core item sets.

Activities of Daily Living↗
PubMed1994

Development of a symptom based outcome measure for asthma.

Measuring symptom specific health outcome is complex, but the methodologies now exist to develop measures with the appropriate properties. As one element of a major programme to develop multidomain health outcome measures for chronic disease, a symptom based measure for asthma care has been developed for use in general practice and outpatient departments. This article outlines the development process, which used a framework recently described in the theoretical literature to show the constraints that scientific criteria place on the development of outcome measures and the means of overcoming such limiting factors. Although substantial effort is required to undertake a rigorous process of development, useful tools are the result. Two five item, symptom based outcome measures for adult asthma are described.

Ambulatory Care↗
PubMed1994

Decision-making by parents and children in paediatric hand surgery.

The task of decision-making about microvascular toe-transfer surgery is a complex one for parents and their children. The process involves balancing risks and benefits within the context of the emotional responses of the parents and the future needs of their children. This paper describes a model of clinical practice which incorporates that process through a multi-disciplinary approach. The factors which influenced parents in their decision are examined, and the issue of the competence of the child to participate is discussed. 34 families were assessed, of whom 7 did not proceed with surgery. It was found that parents were more influenced by factors within the process, such as communication, than by concerns about technical outcome. Specialised psychological counselling played an integral role in the making of stable decisions.

Adult↗
PubMed1994

Ultrasound examinations in pregnancy: some suggestions for debate.

OBJECTIVE: to ascertain the number of ultrasound examinations a sample of women received in pregnancy. DESIGN: a retrospective review of 50 sets of case notes of women delivering consecutively in one maternity unit. SETTING: a large maternity unit in Northern England (approximately 5000 deliveries per year). FINDINGS: the mean number of scans received was 2.6 indicating that many women receive an early 'dating' scan as well as a second trimester 'routine' scan. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: first trimester and early mid-trimester scans may be clinically indicated, but we are concerned that they are becoming routine without fundamental questions of safety and efficacy being answered by large controlled trials. In addition, little is known about the possible positive or negative psychological effects of early scans and there is no evidence that they are cost effective.

England↗
PubMed1994

The psychological impact of microvascular free toe transfer for children and their parents.

This paper is based on a prospective study of microvascular toe transfers which examined psychosocial, functional and aesthetic outcome for children with congenital hand anomalies and their parents. 14 families were assessed both pre-operatively and 2 years post-operatively. There were five boys and nine girls. Their ages ranged from 6 months to 13 years (mean age = 5.08 years). The parents were assessed on the basis of a parental adjustment measure, a detailed semi-structured interview and a measure of anxiety and depression. The children were assessed on the basis of behaviour and social competence, social experience, self-consciousness about the hand and the perceptions of their own functional competence. Both parents and children were asked to rate their satisfaction with the hand. In addition, function and appearance was assessed using an independent professional panel. It was found that parental adjustment to the hand was an important independent variable in determining psychosocial outcome. The children of poorly-adjusted parents had more social and psychological problems prior to surgery, and showed an increase in behavioural problems after surgery. Their parents were less anxious and happier after surgery and it was of particular benefit to them. The children of well-adjusted parents had fewer pre-operative problems and showed a general slight improvement after surgery. For all the children, there was a significant improvement in both function and appearance of the hands after surgery.

Adolescent↗
PubMed1990

Respiratory illness in children: what makes parents decide to consult?

Parents of a stratified random sample of 234 children from 21 training practices in north east England were interviewed at home. All these children had been reported in a postal questionnaire as having had a cough between six and 10 weeks before the interview. Interviews covered social characteristics of the family, the severity of the child's cough and the child's previous respiratory history. These data were analysed using the statistical technique of logistic regression. This produced a good model of consulting behaviour. The model showed that a doctor was likely to be consulted if the child had severe symptoms, or if the cough affected the child's behaviour. This suggests that most parents deciding whether to consult the doctor make careful decisions based on what they see as objective criteria. No social characteristic had a significant influence on the decision to consult the doctor over and above the influence of the characteristics and effect of the cough itself.

Adult↗
PubMed1984

Evaluating breast-milk intake by test weighing: a portable electronic balance suitable for community and field studies.

A K-Tron Digital Scale (Model DS-1) was used to weigh a group of 52 new born babies. The regression of the weights on true weights obtained with a Sartorius electronic balance 3806MP was 0.9911, with an estimated residual variance of 5.25. With the same babies weighed on a Marsden Weighmaster, the estimated residual variance was 68.93. Data from published studies on other balances are presented for comparison. The K-Tron is a reliable, portable, battery operated balance suitable for measuring milk intake by test weighing in homes or in the field.

Biometry↗