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Decision-making deficits, assessed cognitively, are often associated with mental health symptoms, however, this relationship is not fully understood. This paper explores the relationship between mental health disorders and decision-making, using the Cambridge Gambling Task (CGT). Our study investigated how decision-making varied across 20 different mental health conditions compared to controls in a sample of 572 young adults from the Minneapolis and Chicago metropolitan areas, using a computerized laboratory-based task. Almost all mental health conditions were associated with at least mild (i.e. at least small effect size) impairment in all three studied parameters of the CGT (risk adjustment, quality of decision-making and overall proportion of bet). Notably, binge eating disorder had the largest cognitive impairment and gambling disorder had moderate impairment. Post-traumatic stress disorder (PTSD) was associated with impaired decision-making while obsessive-compulsive disorder (OCD) and depression showed moderate impairment. Additionally, half of the disorders assessed had moderate to large impairment in risk adjustment.These findings suggest that mental health conditions may have a more complex cognitive profile than previously thought, and a better understanding of these impairments may aid in risk assessment and targeted clinical interventions. This study underscores the need for further research to determine the causal pathways between mental health conditions and cognition, as well as to better understand the day-to-day impact of such deficits.
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BACKGROUND: Symptoms of attention deficit hyperactivity disorder (ADHD) and trait impulsivity have been associated with disordered eating but are seldom assessed in community studies, or longitudinally and little is known about the mediating mechanisms. METHODS: We tested associations between ADHD symptoms and disordered eating cross-sectionally and between trait impulsivity and disordered eating longitudinally. We utilised data from a normative cohort of young adults (642 participants: 65% female, Mage = 23 years). Participants were classified as high risk or low risk for disordered eating using the SCOFF instrument. In the first two steps of both cross-sectional and longitudinal hierarchical logistic regression models, demographics and covariates were entered. For the cross-sectional regression, Adult ADHD self-report scale (ASRS) scores, separated into inattentive and hyperactive/impulsive symptoms, were entered in the third step. In a separate longitudinal model, Barratt impulsivity scale subscales (attentional, motor and non-planning impulsivity) were entered in the third step. Depression, as assessed by the moods and feelings questionnaire (MFQ), was examined as a mediator. RESULTS: Cross-sectionally, sex, MFQ score and inattentive symptoms predicted disordered eating risk (model R2 = 20%). Longitudinally, sex, MFQ score and attentional impulsivity predicted disordered eating risk (model R2 = 16%). The relationship between inattentive symptoms and the disordered eating risk was partially mediated by MFQ score, whereas the relationship between attentional impulsivity and the disordered eating risk was fully mediated by MFQ scores. CONCLUSIONS: These data highlight (1) a specific role for inattentive symptoms of ADHD and (2) the importance of both depression and impulsivity in predicting eating disorder risk.
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Trastorno por Déficit de Atención con Hiperactividad , Trastornos de Alimentación y de la Ingestión de Alimentos , Humanos , Femenino , Adulto Joven , Adulto , Masculino , Trastorno por Déficit de Atención con Hiperactividad/diagnóstico , Estudios Transversales , Conducta Impulsiva , Encuestas y CuestionariosRESUMEN
Competency-based medical education (CBME) curricula are becoming increasingly common in graduate medical education. Put simply, CBME is focused on educational outcomes, is independent of methods and time, and is composed of achievable competencies.1 In spite of widespread uptake, there remains much to learn about implementing CBME at the program level. Leveraging the collective experience of program leaders at Queen's University, where CBME simultaneously launched across 29 specialty programs in 2017, this paper leverages change management theory to provide a short summary of how program leaders can navigate the successful preparation, launch, and initial implementation of CBME within their residency programs.
Les programmes de formation médicale fondée sur les compétences (FMFC) sont de plus en plus répandus dans les études supérieures en médecine. En termes simples, la FMFC est centrée sur les résultats scolaires, elle est indépendante des méthodes et du temps, et est constituée de compétences réalisables.1 Malgré cette adoption généralisée, il reste encore beaucoup à apprendre sur la mise en Åuvre de la FMFC au niveau des programmes. Tirant profit de l'expérience collective des responsables de programmes à l'Université Queen, où la FMFC a été lancée simultanément dans 29 programmes de spécialité en 2017,le présent article s'appuie sur la théorie de la gestion du changement pour produire un court résumé de la manière dont les responsables de programmes peuvent gérer avec succès la préparation, le lancement et la mise en Åuvre initiale de la FMFC au sein de leurs programmes de résidence.
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The Internet is now all-pervasive across much of the globe. While it has positive uses (e.g. prompt access to information, rapid news dissemination), many individuals develop Problematic Use of the Internet (PUI), an umbrella term incorporating a range of repetitive impairing behaviours. The Internet can act as a conduit for, and may contribute to, functionally impairing behaviours including excessive and compulsive video gaming, compulsive sexual behaviour, buying, gambling, streaming or social networks use. There is growing public and National health authority concern about the health and societal costs of PUI across the lifespan. Gaming Disorder is being considered for inclusion as a mental disorder in diagnostic classification systems, and was listed in the ICD-11 version released for consideration by Member States (http://www.who.int/classifications/icd/revision/timeline/en/). More research is needed into disorder definitions, validation of clinical tools, prevalence, clinical parameters, brain-based biology, socio-health-economic impact, and empirically validated intervention and policy approaches. Potential cultural differences in the magnitudes and natures of types and patterns of PUI need to be better understood, to inform optimal health policy and service development. To this end, the EU under Horizon 2020 has launched a new four-year European Cooperation in Science and Technology (COST) Action Programme (CA 16207), bringing together scientists and clinicians from across the fields of impulsive, compulsive, and addictive disorders, to advance networked interdisciplinary research into PUI across Europe and beyond, ultimately seeking to inform regulatory policies and clinical practice. This paper describes nine critical and achievable research priorities identified by the Network, needed in order to advance understanding of PUI, with a view towards identifying vulnerable individuals for early intervention. The network shall enable collaborative research networks, shared multinational databases, multicentre studies and joint publications.
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Conducta Adictiva , Conducta Compulsiva , Internacionalidad , Internet , Investigación , Europa (Continente) , HumanosRESUMEN
BACKGROUND: The concepts of impulsivity and compulsivity are commonly used in psychiatry. Little is known about whether different manifest measures of impulsivity and compulsivity (behavior, personality, and cognition) map onto underlying latent traits; and if so, their inter-relationship. METHODS: A total of 576 adults were recruited using media advertisements. Psychopathological, personality, and cognitive measures of impulsivity and compulsivity were completed. Confirmatory factor analysis was used to identify the optimal model. RESULTS: The data were best explained by a two-factor model, corresponding to latent traits of impulsivity and compulsivity, respectively, which were positively correlated with each other. This model was statistically superior to the alternative models of their being one underlying factor ('disinhibition') or two anticorrelated factors. Higher scores on the impulsive and compulsive latent factors were each significantly associated with worse quality of life (both p < 0.0001). CONCLUSIONS: This study supports the existence of latent functionally impairing dimensional forms of impulsivity and compulsivity, which are positively correlated. Future work should examine the neurobiological and neurochemical underpinnings of these latent traits; and explore whether they can be used as candidate treatment targets. The findings have implications for diagnostic classification systems, suggesting that combining categorical and dimensional approaches may be valuable and clinically relevant.
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Conducta Compulsiva/fisiopatología , Conducta Impulsiva/fisiología , Trastornos Mentales/fisiopatología , Personalidad/fisiología , Adolescente , Adulto , Conducta Compulsiva/clasificación , Análisis Factorial , Femenino , Humanos , Conducta Impulsiva/clasificación , Masculino , Trastornos Mentales/clasificación , Modelos Estadísticos , Personalidad/clasificación , Psiquiatría/métodos , Adulto JovenRESUMEN
The use of models by ecologists and environmental managers, to inform environmental management and decision-making, has grown exponentially in the past 50 years. Due to logistical, economical, and theoretical benefits, model users frequently transfer preexisting models to new sites where data are scarce. Modelers have made significant progress in understanding how to improve model generalizability during model development. However, models are always imperfect representations of systems and are constrained by the contextual frameworks used during their development. Thus, model users need better ways to evaluate the possibility of unintentional misapplication when transferring models to new sites. We propose a method of describing a model's application niche for use during the model selection process. Using this method, model users synthesize information from databases, past studies, and/or past model transfers to create model performance curves and heat maps. We demonstrated this method using an empirical model developed to predict the ecological condition of plant communities in riverine wetlands of the Appalachian Highland physiographic region, U.S.A. We assessed this model's transferability and generalizability across (1) riverine wetlands in the contiguous U.S.A., (2) wetland types in the Appalachian Highland physiographic region, and (3) wetland types in the contiguous U.S.A. With this methodology and a discussion of its critical steps, we set the stage for further inquiries into the development of consistent and transparent practices for model selection when transferring a model.
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The Overseas Registration Examination is a route to entry to the UK Dentists Register for dentists who have qualified outside the European Economic Area. The role of the examination is to protect the public by ensuring that such dentists meet minimum standards of competence. Candidates invest considerable time and resource in attempting the examination. For these reasons it is essential that the examination is both robust and fair. This paper describes the fundamental principles of assessment underpinning the design of the examination and the steps taken by the General Dental Council's ORE Advisory Group to assure its ongoing quality.
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Competencia Clínica , Odontólogos , HumanosRESUMEN
OBJECTIVE: Research on health correlates in gamblers has found an association between gambling and obesity. The neurocognitive underpinnings of impulsivity may be useful targets for understanding and ultimately treating individuals with both gambling and obesity problems. METHOD: 207 non-treatment seeking young adults (18-29 years) with subsyndromal gambling disorder were recruited from the community. Subjects were grouped according to weight ('normal weight' BMI<25, 'overweight' BMI≥25; or 'obese' BMI≥30). Measures relating to gambling behaviour and objective computerized neurocognitive measures were collected. RESULTS: Of the 207 subjects, 22 (10.6%) were obese and 49 (23.7%) were overweight. The obese gamblers consumed more nicotine (packs per day equivalent) and reported losing more money per week to gambling. Obese gamblers exhibited significant impairments in terms of reaction times for go trials on the stop-signal test (SST), quality of decision making and risk adjustment on the Cambridge Gamble Test (CGT), and sustained attention on the rapid visual information processing task (RVP). CONCLUSION: Obesity was associated with decision making and sustained attention impairments in gamblers, along with greater monetary loss due to gambling. Future work should use longitudinal designs to examine the temporal relationship between these deficits, weight, other impulsive behaviour, and functional impairment.
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Toma de Decisiones , Juego de Azar , Obesidad , Tiempo de Reacción , Asunción de Riesgos , Adulto , Atención , Índice de Masa Corporal , Femenino , Juego de Azar/diagnóstico , Juego de Azar/fisiopatología , Juego de Azar/psicología , Humanos , Conducta Impulsiva , Masculino , Pruebas Neuropsicológicas , Obesidad/diagnóstico , Obesidad/fisiopatología , Obesidad/psicología , Escalas de Valoración Psiquiátrica , Estadística como Asunto , Análisis y Desempeño de TareasRESUMEN
OBJECTIVE: To compare the efficacy of clonidine versus phenobarbital in reducing morphine sulfate treatment days for neonatal abstinence syndrome (NAS). STUDY DESIGN: Prospective, non-blinded, block randomized trial at a single level III NICU (Neonatal Intensive Care Unit). Eligible infants were treated with a combination of medications as per protocol. Primary outcome was treatment days with morphine sulfate. Secondary outcomes were the mean total morphine sulfate dose, outpatient phenobarbital days, adverse events and treatment failures. RESULTS: A total of 82 infants were eligible, of which 68 were randomized with 34 infants in each study group. Adjusting for covariates phenobarbital as compared with clonidine had shorter morphine sulfate treatment days (-4.6, 95% confidence interval (CI): -0.3, -8.9; P=0.037) with no difference in average morphine sulfate total dose (1.1 mg kg(-1), 95% CI: -0.1, 2.4; P=0.069). Post-discharge phenobarbital was continued for an average of 3.8 months (range 1 to 8 months). No other significant differences were noted. CONCLUSION: Phenobarbital as adjunct had clinically nonsignificant shorter inpatient but significant overall longer therapy time as compared with clonidine.
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Agonistas de Receptores Adrenérgicos alfa 2/uso terapéutico , Analgésicos Opioides/efectos adversos , Clonidina/uso terapéutico , Morfina/administración & dosificación , Síndrome de Abstinencia Neonatal/tratamiento farmacológico , Fenobarbital/uso terapéutico , Agonistas de Receptores Adrenérgicos alfa 2/administración & dosificación , Analgésicos Opioides/administración & dosificación , Análisis de Varianza , Clonidina/administración & dosificación , Quimioterapia Combinada , Femenino , Humanos , Recién Nacido , Masculino , Estudios ProspectivosRESUMEN
The opioid system is implicated in the hedonic and motivational processing of food, and in binge eating, a behaviour strongly linked to obesity. The aim of this study was to evaluate the effects of 4 weeks of treatment with the mu-opioid receptor antagonist GSK1521498 on eating behaviour in binge-eating obese subjects. Adults with body mass index ≥ 30 kg m(-2) and binge eating scale scores ≥ 19 received 1-week single-blind placebo run-in, and were then randomized to 28 days with either 2 mg day(-1) GSK1521498, 5 mg day(-1) GSK1521498 or placebo (N=21 per arm) in a double-blind parallel group design. The outcome measures were body weight, fat mass, hedonic and consummatory eating behaviour during inpatient food challenges, safety and pharmacokinetics. The primary analysis was the comparison of change scores in the higher-dose treatment group versus placebo using analysis of covariance at each relevant time point. GSK1521498 (2 mg and 5 mg) was not different from placebo in its effects on weight, fat mass and binge eating scores. However, compared with placebo, GSK1521498 5 mg day(-1) caused a significant reduction in hedonic responses to sweetened dairy products and reduced calorific intake, particularly of high-fat foods during ad libitum buffet meals, with some of these effects correlating with systemic exposure of GSK1521498. There were no significant effects of GSK1521498 2 mg day(-1) on eating behaviour, indicating dose dependency of pharmacodynamics. GSK1521498 was generally well tolerated and no previously unidentified safety signals were detected. The potential for these findings to translate into clinically significant effects in the context of binge eating and weight regain prevention requires further investigation.
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Bulimia/tratamiento farmacológico , Conducta Alimentaria/efectos de los fármacos , Indanos/farmacología , Receptores Opioides mu/antagonistas & inhibidores , Triazoles/farmacología , Adolescente , Adulto , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Femenino , Humanos , Indanos/administración & dosificación , Indanos/uso terapéutico , Masculino , Persona de Mediana Edad , Triazoles/administración & dosificación , Triazoles/uso terapéutico , Adulto JovenRESUMEN
Obsessive-compulsive disorder (OCD) is characterized by obsessions (intrusive thoughts) and compulsions (repetitive ritualistic behaviours) leading to functional impairment. Accumulating evidence links these conditions with underlying dysregulation of fronto-striatal circuitry and monoamine systems. These abnormalities represent key targets for existing and novel treatment interventions. However, the brain bases of these conditions and treatment mechanisms are still not fully elucidated. Animal models simulating the behavioural and clinical manifestations of the disorder show great potential for augmenting our understanding of the pathophysiology and treatment of OCD. This paper provides an overview of what is known about OCD from several perspectives. We begin by describing the clinical features of OCD and the criteria used to assess the validity of animal models of symptomatology; namely, face validity (phenomenological similarity between inducing conditions and specific symptoms of the human phenomenon), predictive validity (similarity in response to treatment) and construct validity (similarity in underlying physiological or psychological mechanisms). We then survey animal models of OC spectrum conditions within this framework, focusing on (i) ethological models; (ii) genetic and pharmacological models; and (iii) neurobehavioural models. We also discuss their advantages and shortcomings in relation to their capacity to identify potentially efficacious new compounds. It is of interest that there has been rather little evidence of 'false alarms' for therapeutic drug effects in OCD models which actually fail in the clinic. While it is more difficult to model obsessive cognition than compulsive behaviour in experimental animals, it is feasible to infer cognitive inflexibility in certain animal paradigms. Finally, key future neurobiological and treatment research areas are highlighted.
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Modelos Animales de Enfermedad , Trastorno Obsesivo Compulsivo/tratamiento farmacológico , Trastorno Obsesivo Compulsivo/psicología , Investigación Biomédica Traslacional , Animales , Trastornos de Ansiedad/diagnóstico , Trastornos de Ansiedad/patología , Trastornos de Ansiedad/psicología , Femenino , Humanos , Masculino , Trastorno Obsesivo Compulsivo/diagnóstico , Trastorno Obsesivo Compulsivo/patología , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND: As a behavioral addiction with clinical and phenomenological similarities to substance addiction, recreational and pathological gambling represent models for studying the neurobiology of addiction, without the confounding deleterious brain effects which may occur from chronic substance abuse. METHOD: A community sample of individuals aged 18-65 years who gamble was solicited through newspaper advertising. Subjects were grouped a priori into three groups (no-risk, at-risk, and pathological gamblers) based on a diagnostic interview. All subjects underwent a psychiatric clinical interview and neurocognitive tests assessing motor impulsivity and cognitive flexibility. Subjects with a current axis I disorder, history of brain injury/trauma, or implementation or dose changes of psychoactive medication within 6 weeks of study enrollment were excluded. RESULTS: A total of 135 no-risk, 69 at-risk and 46 pathological gambling subjects were assessed. Pathological gamblers were significantly older, and exhibited significant deficiencies in motor impulse control (stop-signal reaction times), response speed (median 'go' trial response latency) and cognitive flexibility [total intra-dimensional/extra-dimensional (IDED) errors] versus controls. The finding of impaired impulse control and cognitive flexibility was robust in an age-matched subgroup analysis of pathological gamblers. The no-risk and at-risk gambling groups did not significantly differ from each other on task performance. CONCLUSIONS: Impaired response inhibition and cognitive flexibility exist in people with pathological gambling compared with no-risk and at-risk gamblers. The early identification of such illness in adolescence or young adulthood may aid in the prevention of addiction onset of such disabling disorders.
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Conducta Adictiva/psicología , Juego de Azar/epidemiología , Juego de Azar/psicología , Adolescente , Adulto , Anciano , Análisis de Varianza , Conducta Adictiva/diagnóstico , Conducta Adictiva/epidemiología , Cognición , Femenino , Juego de Azar/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Tiempo de Reacción , Factores de Riesgo , Trastornos Relacionados con Sustancias/epidemiología , Trastornos Relacionados con Sustancias/psicología , Adulto JovenRESUMEN
BACKGROUND: Impairments in working memory are present in many psychiatric illnesses such as attention-deficit hyperactivity disorder (ADHD) and schizophrenia. The dopamine transporter and catechol-O-methyltransferase (COMT) are proteins involved in dopamine clearance and the dopamine system is implicated in the modulation of working memory (WM) processes and neurochemical models of psychiatric diseases. The effects of functional polymorphisms of the dopamine transporter gene (DAT1) and the COMT gene were investigated using a visuospatial and numerical n-back working memory paradigm. Our n-back task was designed to reflect WM alone, and made no demands on higher executive functioning. METHOD: A total of 291 healthy volunteers (aged 18-45 years) were genotyped and matched for age, sex, and Barratt Impulsivity Scale (BIS) and National Adult Reading Test (NART) scores. To assess individual gene effects on WM, factorial mixed model analysis of variances (ANOVAs) were conducted with the between-subjects factor as genotype and difficulty level (0-, 1-, 2- and 3-back) entered as the within-subjects factor. RESULTS: The analysis revealed that the DAT1 or COMT genotype alone or in combination did not predict performance on the n-back task in our sample of healthy volunteers. CONCLUSIONS: Behavioral effects of DAT1 and COMT polymorphisms on WM in healthy volunteers may be non-existent, or too subtle to identify without exceedingly large sample sizes. It is proposed that neuroimaging may provide more powerful means of elucidating the modulatory influences of these polymorphisms.
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Catecol O-Metiltransferasa/genética , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/genética , Memoria a Corto Plazo , Adolescente , Adulto , Catecol O-Metiltransferasa/fisiología , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/fisiología , Femenino , Estudios de Asociación Genética , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Reacción en Cadena de la Polimerasa , Polimorfismo Genético , Adulto JovenRESUMEN
Previous research has demonstrated cognitive-enhancing effects of modafinil in humans and generated evidence for its therapeutic potential in psychiatric disorders. The neurochemical basis of these effects remains unresolved although a role for α1-adrenoceptors has been hypothesised. In this within-subject, double-blind, placebo-controlled study, 12 healthy male adults received modafinil (300 mg), the α1-adrenoceptor antagonist prazosin (3 mg), both together and placebo on separate occasions at least 5 days apart. Cognitive effects were assessed using a well-validated testing battery focusing on executive and working memory functions. Blood pressure, heart rate and salivary α-amylase (sAA) were measured at hourly intervals. Cognitive effects of modafinil and prazosin were identified at the difficult levels of the One-Touch Stockings of Cambridge (OTSOC) planning task. Prazosin antagonized the error-reducing effect of modafinil when the agents were given together. In contrast, the combined agents acted synergistically to increase time taken to complete OTSOC problems compared with placebo. The tachycardic and sAA-elevating effects of prazosin were also potentiated by concurrent modafinil administration. The current data suggest that the cognitive effects of modafinil on performance accuracy and latency are dissociable in terms of their neurochemical mechanisms. Our findings support the hypothesised involvement of α1-adrenoceptors in some of the cognitive-enhancing effects of modafinil and warrant further investigation.
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Antagonistas de Receptores Adrenérgicos alfa 1/farmacología , Compuestos de Bencidrilo/farmacología , Estimulantes del Sistema Nervioso Central/farmacología , Cognición/efectos de los fármacos , Memoria/efectos de los fármacos , Prazosina/farmacología , Adolescente , Antagonistas de Receptores Adrenérgicos alfa 1/administración & dosificación , Adulto , Compuestos de Bencidrilo/administración & dosificación , Estimulantes del Sistema Nervioso Central/administración & dosificación , Método Doble Ciego , Quimioterapia Combinada , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Masculino , Memoria a Corto Plazo , Modafinilo , Prazosina/administración & dosificación , Desempeño Psicomotor/efectos de los fármacos , Desempeño Psicomotor/fisiología , Tiempo de Reacción/efectos de los fármacos , Tiempo de Reacción/fisiología , Adulto JovenAsunto(s)
Goma de Mascar/efectos adversos , Colon/diagnóstico por imagen , Cuerpos Extraños/diagnóstico por imagen , Tomografía de Emisión de Positrones , Adhesividad , Adulto , Colon/cirugía , Colonoscopía , Reacciones Falso Positivas , Femenino , Cuerpos Extraños/cirugía , Humanos , Tomografía Computarizada por Rayos XAsunto(s)
Angiodisplasia/diagnóstico , Estenosis de la Válvula Aórtica/diagnóstico , Hemorragia Gastrointestinal/diagnóstico , Angiodisplasia/terapia , Endoscopía Capsular , Colonoscopía , Diagnóstico Diferencial , Endoscopía del Sistema Digestivo , Femenino , Hemorragia Gastrointestinal/terapia , Humanos , Coagulación con Láser , Persona de Mediana Edad , Sangre OcultaRESUMEN
This randomised trial compared the results of carpal tunnel decompression using the TM Indiana Tome (Biomet, Warsaw, Indiana, USA) and a standard limited palmar open incision. Two hundred patients were randomly selected to have a carpal tunnel decompression with either the Indiana Tome or a limited palmar technique. They were assessed clinically for 3 months and using the Levine-Katz self-assessment evaluation for 7 years. After 7 years, there were 62 returned questionnaires from the open group and 53 from the Tome group. There were no significant differences in functional scores, pain, scar tenderness, pinch and grip strength at 3 months. There were two complications in the open group and nine in the Tome group, including one median nerve injury. There was both a higher rate of immediate complications, and more recurrences and persisting symptoms at 7 years in the Indiana Tome group.
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Síndrome del Túnel Carpiano/cirugía , Descompresión Quirúrgica/instrumentación , Procedimientos Ortopédicos/instrumentación , Estudios de Seguimiento , Humanos , Procedimientos Quirúrgicos Mínimamente Invasivos , Procedimientos Ortopédicos/métodos , Complicaciones PosoperatoriasRESUMEN
A central focus of pollination biology is to document the relative effectiveness of different flower visitors as pollinators. Ongoing research seeks to determine the role that introduced honey bees (Apis mellifera L.) play in the pollination of both invasive and native plants. Here we report on the importance of A. mellifera as pollinators of a California native plant, Triteleia laxa Bentham. In observation plots and transect censuses, A. mellifera overwhelmingly dominated the T. laxa flower visitor assemblage. We believe the proximity to agriculture, where A. mellifera density is higher relative to areas far from agriculture, contributes to the discrepancy between A. mellifera abundance at the two sites. Although A. mellifera were inferior flower visitors qualitatively (visited less flowers per minute), they were the most frequent interactors with flowers. Furthermore, the proportion of visits to flowers on the same plant among flower visitor species did not differ, suggesting a general mechanism by which insects forage at T. laxa flowers and that A. mellifera do not cause more deleterious geitonogamy than do native pollinators. Flower visitation rates as a function of floral display size did not differ between A. mellifera and other flower visitors. The difference in the magnitude of flower visitation (largely by A. mellifera) between sites is consistent with a difference in seed set between sites. These results suggest that non-native A. mellifera bees can play an important role in the pollination of native plant species.
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Abejas , Conducta Animal , Flores/fisiología , Liliaceae/fisiología , Polinización , Animales , California , Dípteros , Ecosistema , Lepidópteros , Semillas/crecimiento & desarrollo , Factores de TiempoRESUMEN
OBJECTIVES: To assess the ability of the new software SonoAVC to measure follicular volume and to compare these volume calculations with those made by conventional methods. METHODS: Three-dimensional ultrasound imaging was used to acquire volumetric data from the ovaries of 51 women undergoing controlled ovarian stimulation as part of in-vitro fertilization treatment. All assessments were performed on the day of oocyte retrieval and the true volume of each follicle was ascertained by manual measurement of the follicular aspirate. SonoAVC was used to automatically measure the volume of follicles and to provide three perpendicular diameters (xyz diameters), which were used to estimate volume using the sphere formula. The sphere formula was also used to estimate the volume from manual measurements of follicle diameter derived from conventional two-dimensional (2D) displays. Virtual Organ Computer-aided AnaLysis (VOCAL) was also used to measure volume, and the validity of each technique was compared using limits of agreement. RESULTS: Two hundred and twenty-four follicles with a mean follicular volume of 3.7 (range, 0.4-16.2) cm(3) were studied. SonoAVC provided highly accurate automatic follicular volume measurements in all cases. Volume estimations made from the automatic maximal follicular diameter measurements (xyz diameters) were less valid. VOCAL proved highly valid but was less accurate than SonoAVC. Volumes estimated from manually derived follicular diameter measurements were the least accurate. CONCLUSIONS: SonoAVC provides highly valid, automatic measurements of follicular volume. These measurements are more accurate than volumes estimated from 2D manual measurements, automated measurements of follicular diameter and those calculated using VOCAL.