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Biomedical subjects

I Harvey

Publications and source records attributed to I Harvey.

At least 91 records · Page 5Linked to original sources
PubMed1997

Artificial evolution: a new path for artificial intelligence?

Recently there have been a number of proposals for the use of artificial evolution as a radically new approach to the development of control systems for autonomous robots. This paper explains the artificial evolution approach, using work at Sussex to illustrate it. The paper revolves around a case study on the concurrent evolution of control networks and visual sensor morphologies for a mobile robot. Wider intellectual issues surrounding the work are discussed, as is the use of more abstract evolutionary simulations as a new potentially useful tool in theoretical biology.

Artificial Intelligence↗
PubMed1997

Patients' experience of epilepsy and health care.

OBJECTIVE: The aim of this study was to assess the severity of epilepsy and its effect on patients lives, and to describe patients' use of and attitudes to health care. METHOD: A questionnaire was sent to 595 people with epilepsy identified from 14 general practices in north-west Bristol. All patients aged 16 years and over receiving anti-epileptic medication for their epilepsy were included in the study. Areas investigated included severity of epilepsy and its effect on quality of life, anti-epileptic medication and its perceived effect, health care utilization and preferences for health care. RESULTS: Seizure frequency was strongly associated with adverse effects of epilepsy. Attacks of epilepsy were experienced at least monthly by 20.4% (95% confidence intervals (Cl) 17.0-23.7%) of patients, 29.4% (25.4-33.4%) took more than one anti-epileptic drug, 56.1% (50.1-62.2%) reported drug side effects, 74.1% (70.3-77.8%) would prefer to receive all or most of their epilepsy care in a general practice setting, and 69.8% (63.5-76.2%) would like contact with a primary care-based epilepsy specialist nurse. During the previous year 42.4% (35.9-48.8%) of patients had not seen a doctor about their epilepsy. Of patients who had attended the general practice only 13.4% (9.6-17.2%) had regular arrangements to see their GP about epilepsy. Patients receiving both primary and secondary care had the greatest needs and wants for improved care. CONCLUSIONS: Structured care, including regular appointments, co-ordination of primary and secondary care, and increased monitoring and discussion, may improve the quality of life of people with epilepsy, but requires evaluation.

Adolescent↗
PubMed1997

Tardive dyskinesia: who is at risk?

Tardive dyskinesia (TD) has been associated with female gender, affective symptoms and good outcome, but also with negative symptoms, cognitive deterioration and deteriorating illness course. Furthermore, antipsychotic medication is thought to be an important risk factor, yet abnormal movements also occur in patients who have never received such medication. We followed 166 subjects with recent onset of psychotic illness and brief previous exposure to antipsychotic medication. Information on 17 previously reported risk factors was available for 125 patients at baseline and, for factors that vary over time, again at follow-up 4 years later (median, 50 months; interquartile range, 29-70). Movement disorder was assessed at follow-up using the Abnormal Involuntary Movement Scale (AIMS). Six noninteracting variables were independently associated with the 4-year risk of TD: male sex (OR, 2.5; 95% CI, 1.1-5.0), age (OR over quartiles at baseline, 1.6; 95% CI, 1.1-2.2), lack of insight at baseline (OR over four categories, 2.0; 95% CI, 1.2-3.2), time on antipsychotics during the follow-up period (OR over quartiles, 2.3; 95% CI, 1.5-3.4), an increase in negative symptoms during the follow-up period (OR over quartiles, 1.7; 95% CI, 1.2-2.5), and alcohol/drug misuse at follow-up (OR, 3.0; 95% CI, 1.3-7.4). The presence of individual risk factors was found to be of little use as a screening test for subsequent clinically relevant TD. Given the absence of a risk factor, however, the probability that an individual would not develop TD was high. These results suggest that two discrete effects may operate to increase the risk of TD, namely an exogenous factor (medication, drugs), and an illness-related factor, the highest risk being conferred by deteriorating illness course in male patients.

Adult↗
PubMed1997

Did the introduction of general practice fundholding change patterns of emergency admission to hospital?

OBJECTIVES: To test the hypothesis that the introduction of general practice fundholding was associated with a change in the proportion of emergency admissions to hospital. METHODS: Before and after natural experiment with control group. The experimental group was first-wave fundholding general practices in the South Western Regional Health Authority, the control group was all practices that remained non-fundholding as of April 1993. Data were collected on episodes of care in hospitals in the South Western region involving cholecystectomy, hernia repair, intervertebral disc operation and prostatectomy. The additional impact of fundholding status on any underlying changes in proportions of emergency admissions was examined using multiple logistic regression. RESULTS: There was no evidence of an interaction between fundholding status and before/after time period. Odds ratios and confidence intervals for the interaction of general practice fundholding status and time were: prostatectomy 1.02 (0.77 to 1.34); hernia repair 0.94 (0.7 to 1.24); intervertebral disk operations 1.67 (0.8 to 3.47); prostatectomy 0.94 (0.69 to 1.27). CONCLUSIONS: The results provide no evidence that, in the first 2 years of the scheme, fundholding had an impact on the proportion of emergency admissions to hospital.

Budgets↗
PubMed1996

Crystal structure of a eukaryotic (pea seedling) copper-containing amine oxidase at 2.2 A resolution.

BACKGROUND: Copper-containing amine oxidases catalyze the oxidative deamination of primary amines to aldehydes, in a reaction that requires free radicals. These enzymes are important in many biological processes, including cell differentiation and growth, would healing, detoxification and signalling. The catalytic reaction requires a redox cofactor, topa quinone (TPQ), which is derived by post-translational modification of an invariant tyrosine residue. Both the biogenesis of the TPQ cofactor and the reaction catalyzed by the enzyme require the presence of a copper atom at the active site. The crystal structure of a prokaryotic copper amine oxidase from E. coli (ECAO) has recently been reported. RESULTS: The first structure of a eukaryotic (pea seedling) amine oxidase (PSAO) has been solved and refined at 2.2 A resolution. The crystallographic phases were derived from a single phosphotungstic acid derivative. The positions of the tungsten atoms in the W12 clusters were obtained by molecular replacement using E. coli amine oxidase as a search model. The methodology avoided bias from the search model, and provides an essentially independent view of a eukaryotic amine oxidase. The PSAO molecule is a homodimer; each subunit has three domains. The active site of each subunit lies near an edge of the beta-sandwich of the largest domain, but is not accessible from the solvent. The essential active-site copper atom is coordinated by three histidine side chains and two water molecules in an approximately square-pyramidal arrangement. All the atoms of the TPQ cofactor are unambiguously defined, the shortest distance to the copper atom being approximately 6 A. CONCLUSIONS: There is considerable structural homology between PSAO and ECAO. A combination of evidence from both structures indicates that the TPQ side chain is sufficiently flexible to permit the aromatic grouf to rotate about the Cbeta-Cgamma bond, and to move between bonding and non-bonding positions with respect to the Cu atom. Conformational flexibility is also required at the surface of the molecule to allow the substrates access to the active site, which is inaccessible to solvent, as expected for an enzyme that uses radical chemistry.

Amine Oxidase (Copper-Containing)↗
PubMed1996

1H,13C-NMR and X-ray absorption studies of copper(I) glutathione complexes.

The tripeptide glutathione (gamma-L-Glu-L-Cys-Gly, GSH) is an important intracellular reducing agent for Cu(II) and complexation agent for Cu(I). We have studied the complexation of Cu(I) to GSH in aqueous solution at a range of pH values and Cu(I):GSH molar ratios by 1H-NMR and 13C-NMR spectroscopy and X-ray absorption spectroscopy. The NMR data are consistent with formation of a complex with approximate 1:1 stoichiometry [Cu(SG)] as the major species with only thiolate sulfur of GSH binding to Cu(I). The rate of exchange of GSH with GS-Cu was determined to 13 s(-1) at 283 K, pH 6.8. X-ray absorption spectroscopic measurements showed that Cu(I) is coordinated to 3.1+/-0.3 sulfur atoms at approximately 0.222 nm in solutions (and solids) containing GSH:Cu in 1:1 and 2:1 mol ratios. The possible structures of polymeric Cu(I)-glutathione complexes are discussed. The high thermodynamic stability of Cu(I)-S bonds in Cu(I)-glutathione complexes coupled with their kinetic lability may provide efficient and specific pathways for the transport of copper in cells.

Copper↗
PubMed1996

Do obstetric complications cause the earlier age at onset in male than female schizophrenics?

We compared the age at onset of 184 patients with functional psychoses with and without a history of obstetric complications (OCs) as defined by the scale of Lewis et al. (1989). OCs had no significant influence on the age at onset in those patients who had affective psychoses or were non-white. There were 73 white patients with a DSM-III-R diagnosis of schizophrenia. The mean age at onset of those 25 who had a history of at least one definite OC was 2.6 years earlier than that of the 48 patients with no history of OCs. This effect was entirely due to the male patients with histories of OCs who had, on average, a 3.5 years earlier age at onset. There were no gender differences in age at onset among schizophrenics without a history of OCs. We suggest that a subgroup of male patients with a history of OCs is responsible for the earlier age at onset in male compared to female schizophrenics.

Black or African American↗
PubMed1996

The prevention of skin cancer: is there a gap between evidence and practice?

BACKGROUND: Stabilizing of skin cancer incidence by 2005 is a Health of the Nation target and many purchasers and practitioners are actively endeavouring to meet it. This study aims to describe the extent and nature of primary and secondary prevention programmes amongst health authorities in the UK and general practices in Avon and to comment upon the evidential basis for these measures. METHODS: Questionnaire survey (with a second mailing to non-responders), sent to the 205 health authorities in the UK England, Wales, Scotland and Northern Ireland) and 179 general practices in Avon. RESULTS: Primary prevention programmes are being implemented by 89% of health authorities in the UK and 56% of general practices in Avon. Sun avoidance, and use of protective clothing and sunscreens were advised by over 90% of authorities with such programmes. 34% of general practices and 41% of health authorities were providing or purchasing secondary prevention programmes, ranging from conveying information about warning signs in skin lesions to undertaking full scale screening. CONCLUSION: Most authorities are appropriately promoting ultraviolet reduction by use of thickly woven clothing, hats and avoidance of the midday sun. There is greater uncertainty about the appropriate role of sunscreens, which have not been shown experimentally to reduce skin cancer incidence. Whilst there is some evidence of the effectiveness of campaigns to encourage rapid referral to pigmented lesion clinics, there is none to support screening for skin cancers by clinical examination and this approach should not be pursued under our current state of knowledge.

Adolescent↗
PubMed1996

Variation in purchasing for the invasive management of coronary heart disease.

This paper reports the results of a postal questionnaire survey of Directors of Public Health in all health authorities in the United Kingdom (as at March 1994). Our aim was to examine variations in the purchasing of coronary artery bypass grafting, percutaneous transluminal coronary angioplasty and coronary angiography. Information on planned service developments in cardiology was also sought. The response rate was 62%. The mean rate of CABG was 374 per million total population (range 162-710); PTCA 183 (range: 18-648); and coronary angiography 1,010 (range 581-2,334). The mean ratio of invasive treatment to angiography was 1:2 Variations in provision were not related to mortality from coronary heart disease or the availability of a local provider. Those districts purchasing higher levels of CABG tended to purchase higher levels of PTCA (Spearman's r = 0.52). Observed variations in purchasing of invasive treatments and investigation for coronary heart disease do not relate to population "need' as defined by mortality rates from CHD. The greatest variations are seen in the purchasing of PTCA, an intervention whose place in the management of CHD is as yet not fully defined. Consensus guidelines on the appropriate use of these interventions and on population needs are required.

Angioplasty, Balloon, Coronary↗
PubMed1996

Psychopathological syndromes in the functional psychoses: associations with course and outcome.

The aim of this study was to identify underlying dimensions of psychopathology in a cohort of patients with functional psychosis of recent onset, and to examine their prognostic value. Factor analysis of the psychopathological features of 166 consecutively admitted patients with functional psychosis of recent onset revealed seven psychopathological dimensions, which explained 63% of the variance. Five of these seven syndromes bore differential associations with subsequent treatment and illness course, independent of: (i) associations with DSM-III-R diagnosis; (ii) associations with other prognostic factors; and (iii) associations with the baseline values of outcome variables. The most striking associations were shown for an early and insidious onset syndrome with affective flattening, which predicted a more disabled course of illness on three of four outcome dimensions, and which was more common in males and unmarried individuals. A second syndrome, characterized by bizarre behaviour, inappropriate affect, catatonia, and poor rapport showed similar, slightly less striking, associations with illness course, as well as with poor pre-morbid social functioning. A third syndrome, characterized by positive psychotic symptoms was to a lesser degree associated with poorer outcome, whereas a fourth syndrome distinguished by manic symptomatology predicted a more benign illness course. A fifth syndrome identified by lack of insight predicted more time in hospital and admission under a section of the Mental Health Act during the follow-up period. A further finding was that dimensional representations of psychopathological features were considerably more useful than categorical representations (DSM-III-R and ICD-10) as predictors of illness course and treatment decisions.

Adolescent↗
PubMed1996

Non-melanoma skin cancer and solar keratoses. I. Methods and descriptive results of the South Wales Skin Cancer Study.

This study aimed to describe the prevalence and incidence of solar keratoses and skin cancers and the natural history of solar keratoses in a random population sample. It was a cross-sectional study, with follow-up, conducted in South Wales, and involved 1034 subjects aged 60 years and over drawn from the Family Health Services Authority register. The main outcome measures were detection of the presence of solar keratoses and skin cancers on sun-exposed skin and photographic validation of solar keratoses and biopsy confirmation of cancers wherever possible. We found that solar keratosis prevalence was 23% (95% confidence interval 19.5-26.5) and that of skin cancer (all types) 2% (95% confidence interval 1.0-3.5). The incidence rate of solar keratoses was 149 lesions per 1000 person-years and of non-melanoma skin cancer 9 per 1000 person-years. In all 21% (95% CL 16-26) of solar keratoses regressed spontaneously during follow-up. None underwent malignant change. We believe that the failure of individuals to seek medical advice and the variable under-registration of non-melanoma skin cancer makes population-based study important. The high prevalence and incidence of malignant and pre-malignant skin lesions in this random sample raise major public health concerns. The high rate of spontaneous regression of solar keratoses and the low rate of malignant change challenges conventional views about the need for routine treatment of these lesions.

Adult↗
PubMed1996

Non-melanoma skin cancer and solar keratoses II analytical results of the South Wales Skin Cancer Study.

This study aimed to identify risk markers for prevalent solar keratoses (SKs) and squamous cell carcinomata (SCC) combined, for incident SKs and for spontaneous remission of SKs and to evaluate primary preventative measures. It was a cross-sectional study, with follow-up, conducted in South Wales, and involved 1034 subjects aged 60 years and over. The main outcome measures were the presence of and changes in SKs, and presence of skin cancers, on sun-exposed skin, and risk factors for prevalent SKs/SCCs and for incidence and remission of SKs. We found that variables independently associated with prevalent SKs/SCCs were: age [80 + years vs 60-64 years, odds ratio (OR) 3.7]; sex (male vs female OR 2.2); cumulative sun exposure (top quintile vs bottom quintile OR 3.3) and skin type (skin type 1 vs 4 OR 12.4). Use of sunscreen or protective clothing was not protective after controlling for confounders. Males and those who sunbathe infrequently showed greater remission of SKs. Older subjects and those spending most time in the sun in the preceeding 2 years were most likely to develop new SKs. We conclude that the risk factors identified are consistent with results from sunnier countries. The failure of sunscreen or clothing to emerge as protective raises doubts as to whether these measures are as effective in routine use in the general population as theoretical considerations and the limited trial evidence would predict. Recently reported sun exposure appears to influence the risk of developing new SKs.

Aged↗
PubMed1996

A comparison of methods for measuring patient satisfaction with consultations in primary care.

BACKGROUND: Attention needs to be paid to comparing and standardizing methods for measuring patient satisfaction with consultations in primary care. OBJECTIVES: To compare the Medical Interview Satisfaction Scale (MISS) and the Consultation Satisfaction Questionnaire (CSQ) in terms of acceptability, distribution of responses, reliability and gather evidence of validity. In addition, to compare the scores of patients completing the questionnaires immediately after the consultation in the general practitioners' surgeries with those completing the questionnaires later at home. METHODS: The two questionnaires were bound as a single instrument with order determined at random. This was given to patients immediately after their consultations in eight practices in South Glamorgan. RESULTS: One hundred and ninety-eight of 316 (63%) patients completed and returned questionnaires. The distributions of patient satisfaction scores for the two questionnaires were very similar. For the MISS: mean 76.6% (SD 11.4); for the CSQ mean 7.2% (SD 12.6). Correlations between sub-scales ranged from 0.58-0.84 for the MISS and from 0.40-0.79 for the CSQ. The correlation between the overall scales was 0.82. Levels of reliability for the scales and sub-scales were fair to good ranging from 0.78-0.96 for the MISS and from 0.73-0.94 for the CSQ. CONCLUSIONS: The study does not identify one scale as being superior in psychometric terms, however by demonstrating consistency of responses it provides support for the scales as measures of patient satisfaction for use in primary care. The level of inter-correlation suggests that the sub-scales may not be clearly independent of each other and suggests that total scores may be preferred. Lower levels of satisfaction are expressed if patients complete questionnaires at home rather than in general practitioners' surgeries.

Adolescent↗
PubMed1996

Prenatal exposure to influenza and increased cerebrospinal fluid spaces in schizophrenia.

Several epidemiological studies have suggested that maternal exposure to influenza during midgestation is a risk factor for schizophrenia. In exploring the possible pathogenic mechanism, we examined the relationship between computed tomography structural brain measures in 83 schizophrenia patients and 113 controls and also their risk of maternal exposure to influenza. Four brain measures of the cerebrospinal fluid (CSF) spaces (lateral ventricle, maximum third ventricle, sulcal fluid, and sylvian fissure) were investigated in relation to the risk exposure level. In schizophrenia patients, these measures, in particular sylvian fissures, were found to increase with higher levels of risk exposure to influenza during the susceptible period (i.e., midgestation); no such effect was found in controls. These results indicate that risk for midgestational influenza exposure is associated with generalized enlargement of the CSF spaces, especially in the region of the temporal lobe. The findings suggest that certain morphological abnormalities of the brain frequently reported in schizophrenia patients may be partly attributable to antenatal exposure to influenza.

Adult↗
PubMed1996

Methodology for a randomised controlled trial of preschool vision screening. A new approach with the 'ALSPAC' project.

We present the methodology of a population-based Randomised Controlled Trial, comparing an intensive programme of primary preschool vision screening by orthoptists with the usual non-specialist screening. The aims of the trial are to compare the effectiveness and costs of intensive orthoptic screening with non-specialist measures. The orthoptic screening programme will be evaluated both as a composite package and in terms of the screening value of the individual tests at specific ages. This trial is nested within a large population-based longitudinal study. Additional demographic and developmental data on the children in the trial are therefore available. The results of the trial will be used to help clarify which methods of preschool ophthalmic population screening are best in terms of disease detection and cost efficiency.

Amblyopia↗
PubMed1995

Psychosis with good prognosis in Afro-Caribbean people now living in the United Kingdom.

OBJECTIVES: To compare the course and outcome of psychotic illness in a group of Afro-Caribbean patients resident in the United Kingdom and a group of white British patients. DESIGN: Cohort study of consecutive admissions followed up for four years. SUBJECTS: 113 patients with psychotic illness of recent onset admitted to two south London hospitals. MAIN OUTCOME MEASURES: Course of illness, history of self harm, social disability, treatment received, and hospital use adjusted for socioeconomic origin. RESULTS: The Afro-Caribbean group spent more time in a recovered state during the follow up period (adjusted odds ratio 5.0; 95% confidence interval 1.7 to 14.5), were less likely to have had a continuous illness (0.3; 0.1 to 0.8), were less at risk of self harm (0.2; 0.1 to 0.8), and were less likely to have been prescribed antidepressant treatment (0.3; 0.1 to 0.9). There were no differences in hospital use, but the Afro-Caribbean group had more involuntary admissions (8.9; 2.1 to 35.6) and more imprisonments over the follow up period (9.2; 1.6 to 52.3). CONCLUSIONS: Afro-Caribbean patients in the United Kingdom have a better outcome after psychiatric illness than do white people. The combination of high incidence and more benign course of illness of psychotic illness in this group may be due, at least in part, to a greater exposure to precipitants in the social environment.

Adolescent↗