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Biomedical subjects

Paul Robinson

Publications and source records attributed to Paul Robinson.

At least 19 recordsLinked to original sources

Predictors of mental health problems and negative caregiving experiences in carers of adolescents with bulimia nervosa.

OBJECTIVE: This exploratory study focuses on the mental health (MH) and caregiving experience of carers of adolescents with Bulimia Nervosa (BN)/Eating Disorder not otherwise specified (EDNOS), aiming to determine: levels of MH problems in carers and if a negative experience of caregiving predicts carer MH status and which factors predict a negative experience of caregiving. METHOD: Hundred and twelve carers and 68 adolescents with BN/EDNOS completed self-report measures (General Health Questionnaire, Experience of Caregiving Inventory, Level of Expressed Emotion, Self-report Family Inventory, Inventory of Interpersonal Problems). RESULTS: Over half of the carers reported some MH problems and a minority (5.4%) were experiencing considerable difficulties. A negative experience of caregiving predicted carer MH status. Higher weekly contact hours and patient ratings of expressed emotion (EE) predicted a negative experience of caregiving. CONCLUSIONS: Interventions focusing on reducing EE and contact hours could prove beneficial for both patient and caregiver outcomes.

Adolescent↗

Mutations in fast skeletal troponin I, troponin T, and beta-tropomyosin that cause distal arthrogryposis all increase contractile function.

Distal arthrogryposes (DAs) are a group of disorders characterized by congenital contractures of distal limbs without overt neurological or muscle disease. Unexpectedly, mutations in genes encoding the fast skeletal muscle regulatory proteins troponin T (TnT), troponin I (TnI), and beta-tropomyosin (beta-TM) have been shown to cause autosomal dominant DA. We tested how these mutations affect contractile function by comparing wild-type (WT) and mutant proteins in actomyosin ATPase assays and in troponin-replaced rabbit psoas fibers. We have analyzed all four reported mutants: Arg63His TnT, Arg91Gly beta-TM, Arg174Gln TnI, and a TnI truncation mutant (Arg156ter). Thin filaments, reconstituted using actin and WT troponin and beta-TM, activated myosin subfragment-1 ATPase in a calcium-dependent, cooperative manner. Thin filaments containing either a troponin or beta-TM DA mutant produced significantly enhanced ATPase rates at all calcium concentrations without alternating calcium-sensitivity or cooperativity. In troponin-exchanged skinned fibers, each mutant caused a significant increase in Ca2+ sensitivity, and Arg156ter TnI generated significantly higher maximum force. Arg91Gly beta-TM was found to have a lower actin affinity than WT and form a less stable coiled coil. We propose the mutations cause increased contractility of developing fast-twitch skeletal muscles, thus causing muscle contractures and the development of the observed limb deformities.

Actins↗

A multilevel decomposition approach to estimate the role of program location and neighborhood disadvantage in racial disparities in alcohol treatment completion.

Large racial disparities in completion rates from substance abuse treatment programs in urban settings remain largely unexplained, although evidence is accumulating that neighborhood conditions may influence individual substance abuse patterns and consequences. Understanding racial disparities in alcohol treatment completion, in particular, is crucial to resolving health disparities because racial/ethnic minorities bear a disproportionate burden of alcohol-related health consequences. Patient records for all non-homeless African American (N=1677), Hispanic (N=1635), and white (N=1216) alcohol outpatients, ages 18 or older, discharged during 1998-2000 from publicly funded treatment programs in Los Angeles County, the second largest system of publicly funded substance abuse treatment in the United States, were combined with census data. We tested the hypothesis that racial differences in treatment completion are related to differences in neighborhood context, particularly neighborhood-level disadvantage. Estimates from multilevel statistical models indicate that treatment neighborhood disadvantage is independently associated with treatment completion after controlling for patient characteristics and facility- and zip code-level random effects. Results of a Oaxaca decomposition of the regression estimates indicate that racial differences in treatment neighborhood disadvantage account for 32.3% of African American-white differences in treatment completion. Hispanic-white differences in completion, and the effect of home neighborhood disadvantage on completion, were non-significant. We conclude that the location of publicly funded alcohol treatment programs is related to racial disparities in treatment completion, but additional research is necessary to understand the mechanism behind this association.

Adult↗

Functional effects of the DCM mutant Gly159Asp troponin C in skinned muscle fibres.

We recently reported a dilated cardiomyopathy (DCM) causing mutation in a novel disease gene, TNNC1, which encodes cardiac troponin C (TnC). We have determined how this mutation, Gly159Asp, affects contractile regulation when incorporated into muscle fibres. Endogenous troponin in rabbit skinned psoas fibres was partially replaced by recombinant human cardiac troponin containing either wild-type or Gly159Asp TnC. We measured both the force-pCa relationship of these fibres and the activation rate using the caged-Ca(2+) compound nitrophenyl-EGTA. Gly159Asp TnC had no significant effect on either the Ca(2+) sensitivity or cooperativity of force generation when compared to wild type. However, the mutation caused a highly significant (ca. 50%) decrease in the rate of activation. This study shows that whilst not affecting the force-pCa relationship, the mutation Gly159Asp causes a significant decrease in the rate of force production and a change in the relationship between the rate of force production and generated force. In vivo, this mutation may cause both a slowing of force generation and reduction in total systolic force. This represents a novel mechanism by which a cardiomyopathy-causing mutation can affect contractility.

Actin Cytoskeleton↗

Alcohol outlets, gonorrhea, and the Los Angeles civil unrest: a longitudinal analysis.

This study tests the effect of neighborhood changes on gonorrhea rates. Prior studies that indicate gonorrhea rates are associated with alcohol outlet density and neighborhood deterioration have been cross-sectional and cannot establish causality. After the 1992 Civil Unrest in Los Angeles, 270 alcohol outlets surrendered their licenses due to arson and vandalism thus providing a natural experiment. We geocoded all reported gonorrhea cases from 1988 to 1996 in LA County, all annually licensed alcohol outlets, and all properties damaged as a result of the civil unrest. We ran individual growth models to examine the independent effects of changes in alcohol outlets and damaged buildings on gonorrhea. The individual growth model explained over 90% of the residual variance in census tract gonorrhea rates. After the civil unrest, a unit decrease in the number of alcohol outlets per mile of roadway was associated with 21 fewer gonorrhea cases per 100,000 (p<.01) in tracts affected by the Unrest compared to those not affected. Neighborhood alcohol outlets appear to be significantly associated with changes in gonorrhea rates. The findings suggest that efforts to control sexually transmitted diseases, including gonorrhea and HIV, should address contextual factors that facilitate high-risk behaviors and disease transmission.

Adolescent↗

Effects of troponin C isoform on the action of the cardiotonic agent EMD 57033.

The effects of the cardiotonic potentiator EMD 57033 on different TnC (troponin C) isoforms were investigated. Endogenous skeletal TnC was extracted from glycerinated, permeabilized rabbit psoas fibres and replaced with either purified native rabbit psoas TnC (fast TnC) or human recombinant cTnC (cardiac TnC) (3 mg/ml in relaxing solution for 30 min). In both conditions, 10 microM EMD 57033 increased maximal calcium-activated force (Pmax) and gave a leftward shift in the pCa-tension curve. With cTnC, the increase in Pmax was much greater (228%) compared with the effect seen for fast TnC (137%), which was the same as that in unextracted control fibres. When the whole troponin was replaced rather than just TnC, the effects of EMD 57033 on fibres replaced with cTn were the same as with the cTnC subunit alone, except that the force at low Ca2+ concentrations was not increased as much. If TnC was only partially extracted, it was found that the degree of extraction did not influence the effect of EMD 57033, except when force was decreased to below 10% of the pre-extraction Pmax. Dynamic stiffness was not altered by EMD 57033 in any of the preparations. The rate of tension recovery following a release-restretch method (ktr) was decreased by EMD 57033. We conclude that EMD 57033 acts by a rate-modulating effect, and that the quantitative response of this effect is dependent on the TnC isoform present.

Animals↗

Dilated cardiomyopathy mutations in three thin filament regulatory proteins result in a common functional phenotype.

Dilated cardiomyopathy (DCM), characterized by cardiac dilatation and contractile dysfunction, is a major cause of heart failure. Inherited DCM can result from mutations in the genes encoding cardiac troponin T, troponin C, and alpha-tropomyosin; different mutations in the same genes cause hypertrophic cardiomyopathy. To understand how certain mutations lead specifically to DCM, we have investigated their effect on contractile function by comparing wild-type and mutant recombinant proteins. Because initial studies on two troponin T mutations have generated conflicting findings, we analyzed all eight published DCM mutations in troponin T, troponin C, and alpha-tropomyosin in a range of in vitro assays. Thin filaments, reconstituted with a 1:1 ratio of mutant/wild-type proteins (the likely in vivo ratio), all showed reduced Ca(2+) sensitivity of activation in ATPase and motility assays, and except for one alpha-tropomyosin mutant showed lower maximum Ca(2+) activation. Incorporation of either of two troponin T mutants in skinned cardiac trabeculae also decreased Ca(2+) sensitivity of force generation. Structure/function considerations imply that the diverse thin filament DCM mutations affect different aspects of regulatory function yet change contractility in a consistent manner. The DCM mutations depress myofibrillar function, an effect fundamentally opposite to that of hypertrophic cardiomyopathy-causing thin filament mutations, suggesting that decreased contractility may trigger pathways that ultimately lead to the clinical phenotype.

Animals↗

Why do adolescents with bulimia nervosa choose not to involve their parents in treatment?

BACKGROUND: Although the use of family therapy for adolescents with anorexia nervosa is well established, there has been limited research into the efficacy of family therapy in adolescents with bulimia nervosa (BN). No previous research has investigated why individuals with BN do or do not involve their parents in treatment. This is an exploratory study aimed at determining whether there are any differences between these individuals in terms of eating disorder symptomatology, psychopathology, familial risk factors, patients' perception of parental expressed emotion (EE) and family functioning. METHODS: Participants were 85 adolescents with BN or Eating Disorder Not Otherwise Specified, recruited to a randomised controlled evaluation of the cost-effectiveness of cognitive-behavioural guided self-care vs. family therapy. Participants were interviewed regarding the history of their eating disorder and completed self-report measures. RESULTS: Patients who did not involve their parents in treatment were significantly older, had more chronic eating disorder symptoms, exhibited more co-morbid and impulsive behaviours and rated their mothers higher in EE. However, they did not have more severe eating disorder symptomatology. CONCLUSIONS: These preliminary findings, although in need of replication with a larger sample and limited by the attrition rate in some of the self-report measures, indicate that patients who did not involve their parents in treatment may perceive their mothers as having a more blaming and negative attitude towards the patient's illness. Public awareness about BN needs to be raised, focusing on reducing the stigma and negative views attached to this illness.

Adolescent↗

Body checking and its avoidance in eating disorders.

OBJECTIVE: One expression of the core psychopathology of eating disorders is the repeated checking and avoidance of shape or weight. Two studies are reported. The primary purpose of the first was to describe the phenomenology of such body checking and avoidance. The aim of the second was to compare body checking and avoidance in women with and without a clinical eating disorder. METHOD: In Study 1, 64 female patients with clinical eating disorders participated in a semistructured interview assessing the features of body checking and avoidance. In the second study, a self-report questionnaire was used to compare body checking and avoidance in women with and without a clinical eating disorder (n = 110). RESULTS: The majority (92%) of the patients in Study 1 checked their bodies to assess their shape or weight and this was associated significantly with eating disorder symptoms. In Study 2, the clinical group had significantly more body checking and avoidance than the comparison group, and there was a strong association between eating disorder psychopathology and body checking and avoidance. CONCLUSIONS: These findings support the view that body checking and avoidance are direct expressions of the overevaluation of shape and weight. Further work is needed to determine whether these expressions contribute to the maintenance of eating disorders.

Adolescent↗

Thought-shape fusion in eating disorders.

OBJECTIVES: The aims of the present study were (1) to examine the association between a cognitive distortion ('thought-shape fusion') and eating disorder psychopathology and (2) to examine the degree of thought-shape fusion in people with eating disorders and a non-eating-disorder control group. DESIGN: Associations between thought-shape fusion and eating disorder psychopathology were examined and the degree of thought-shape fusion was compared between people with and without clinical eating disorders. METHOD: Forty-two women with clinical eating disorders and a group of 42 age-matched women with no self-reported history of an eating disorder completed self-report questionnaires to assess thought-shape fusion, eating disorder symptoms, body checking and body avoidance, and depression. RESULTS: Thought-shape fusion was significantly associated with eating disorder psychopathology. The majority of the associations remained significant when controlling for levels of depression. Patients with eating disorders showed significantly more thought-shape fusion than the non-clinical controls. CONCLUSIONS: Thought-shape fusion is a cognitive distortion associated with eating disorders. It may be a direct expression of the overevaluation of eating, shape and weight. It is recommended that thought-shape fusion be tackled directly in cases where it is a barrier to changing the core psychopathology of eating disorders.

Adolescent↗

Identification of high-quality consultation practice in primary care: the effects of computer use on doctor-patient rapport.

If the practitioner uses a clinical computer during consultation with the patient there may be adverse effects on the quality of interpersonal communication in the consultation. Greatbach et al showed in 1995 that these adverse effects might be minimised when the practitioner is well-practised and able to put in the background the tasks involving the computer. In the subsequent seven years, as clinical computer systems have become more sophisticated, the clinician may be called on to pay more attention to the content displayed on the computer screen. This study shows that this required level of attention cannot be put in the background, and that general practitioners (GPs) are not able to multitask at this level. Clinicians can use specific communication skills to manage the consultation, so that they are not called on to concentrate on the computer screen and the patient at the same time. The two tasks can be accomplished in the same consultation, but not simultaneously.

Attitude of Health Personnel↗

Is there a digital divide among physicians? A geographic analysis of information technology in Southern California physician offices.

OBJECTIVE: The aim of this study was to determine whether physician offices located in high-minority and low-income neighborhoods have different levels of access to information technology than offices located in lower-minority and higher-income areas. DESIGN: A cross-sectional survey was conducted of pediatrics, family medicine, and general practice offices in Orange County, California. Survey data were linked with community demographic data from the 2000 Census using a geographical information system. RESULTS: Of 307 offices surveyed, 141 responded (46%). Offices located in high-minority and high-poverty areas were as likely to respond as other offices. Among responding offices, 94% had a computer, 77% had Web access, 29% had broadband Internet access, and 53% used computerized scheduling and billing systems. Offices located in minority and low-income communities had equivalent access to each technology. Offices in communities with larger proportions of Hispanics were less likely to have practice Web pages, but other uses of the Internet were not associated with practice location. Offices reported high levels of interest in online clinical systems but also high levels of concern about these systems' usability and confidentiality. Offices with Web access and those with practice management systems expressed greater interest in online clinical systems but also greater levels of concern about usability and confidentiality. These attitudes were equivalent among offices in different communities. CONCLUSION: Primary care offices located in poor and minority communities in a large, suburban county had high levels of access to and interest in Web-based systems. Physicians' offices may therefore provide a venue for online services aimed at improving health outcomes for poor and minority communities. Research is needed in other geographic regions to determine the generalizability of these findings.

Attitude to Computers↗

Beyond the knowledge deficit: recent research into lay and expert attitudes to food risks.

The paper reviews psychological and social scientific research on lay attitudes to food risks. Many experts (scientists, food producers and public health advisors) regard public unease about food risks as excessive. This expert-lay discrepancy is often attributed to a 'knowledge deficit' among lay people. However, much research in psychology and sociology suggests that lay risk assessments are complex, situationally sensitive expressions of personal value systems. The paper is organised around four themes: risk perception, the communication of risk, lay handling of risk, and public trust in institutions and experts. It suggests that an interdisciplinary, contextualised and psychologically sound approach to the study of risk is needed.

Attitude↗

Learning support for the consultation: information support and decision support should be placed in an educational framework.

BACKGROUND: Advances in information technology mean that it is now possible to provide contextually relevant, evidence-based information during the course of the consultation. As a consequence, the practitioner has to consider the new information (from the computer) in the situation of the present consultation and in the light of his or her own experience. This task has to be carried out in a short time, in the presence of the patient. METHOD: Drawing on experience of the development of one decision support system, this paper places that task for the practitioner in an educational framework. We begin by reviewing theories of professional experience and knowledge and go on to look at schema theory and the role of cognitive dissonance and reflection in learning. CONCLUSION: This paper considers the provision of real time decision support in the light of learning and the experienced practitioner. We conclude that framing the implementation of decision support in this way provides useful insights. The key process is learning by the practitioner, in the course of the consultation. This process should be supported by decision support and information support software. There are implications here for the design of such software, and also for the way in which practitioners are trained to use it.

Cognitive Dissonance↗

Four simple questions can help screen for eating disorders.

Current screening instruments for eating disorders are cumbersome to administer and have not been validated in primary care populations. We compared the performance characteristics of 2 screening tools, the SCOFF clinical prediction guide, and a new set of questions, the Eating disorder Screen for Primary care (ESP), using the Questionnaire for Eating Disorders Diagnosis as the independent standard, in 104 consecutive patients from a primary care practice and 129 university students. Twelve percent of the combined population had an eating disorder. One or no abnormal responses to the ESP ruled out an eating disorder (likelihood ratio [LR] 0.0), whereas 3 or more abnormal responses ruled one in (LR 11). The SCOFF questions were less sensitive than predicted (1 or no abnormal responses, LR 0.25), but were as effective at ruling in an eating disorder (3 or more abnormal responses, LR 11).

Feeding and Eating Disorders↗