RESUMEN
PURPOSE: Although cross-sectional studies have demonstrated that trans people present with lower quality of life and wellbeing than the general population, few studies have explored the factors associated with this, particularly in those who have medically transitioned some time ago. This paper aims to fill the gap in the literature on what factors are associated with wellbeing in trans people who initiated medical transition some time ago. METHODS: This study used semi-structured one-to-one interviews with 23 participants to investigate the factors that impact upon the wellbeing of trans people who had initiated Gender Affirming Medical Treatment five or more years ago. The content of the interviews were analysed with an inductive, grounded theory approach to identify common themes within them. RESULTS: The four themes identified include some consistencies with cisgender populations (while being viewed through the lens of trans experience), as well as those more specific to the trans experience. Together these themes were: Interactions with healthcare services; Seeking societal acceptance; Quality of social support; The 'double-edged sword' of media and social media. Each of the themes identifies a factor that participants highlighted as impacting, either positively or negatively, on their wellbeing. CONCLUSIONS: The results highlight the importance of social support, protective legislations, awareness of trans issues in the general public, and the need of improving the knowledge held by non-specialist healthcare providers.
Asunto(s)
Personas Transgénero , Estudios Transversales , Identidad de Género , Humanos , Investigación Cualitativa , Calidad de Vida/psicologíaRESUMEN
BACKGROUND: Sedentary behaviour is any waking behaviour characterised by an energy expenditure of ≤1.5 metabolic equivalent of task while in a sitting or reclining posture. Prolonged bouts of sedentary behaviour have been associated with negative health outcomes in all age groups. We examined qualitative research investigating perceptions and experiences of sedentary behaviour and of participation in non-workplace interventions designed to reduce sedentary behaviour in adult populations. METHOD: A systematic search of seven databases (MEDLINE, AMED, Cochrane, PsychINFO, SPORTDiscus, CINAHL and Web of Science) was conducted in September 2017. Studies were assessed for methodological quality and a thematic synthesis was conducted. Prospero database ID: CRD42017083436. RESULTS: Thirty individual studies capturing the experiences of 918 individuals were included. Eleven studies examined experiences and/or perceptions of sedentary behaviour in older adults (typically ≥60 years); ten studies focused on sedentary behaviour in people experiencing a clinical condition, four explored influences on sedentary behaviour in adults living in socio-economically disadvantaged communities, two examined university students' experiences of sedentary behaviour, two on those of working-age adults, and one focused on cultural influences on sedentary behaviour. Three analytical themes were identified: 1) the impact of different life stages on sedentary behaviour 2) lifestyle factors influencing sedentary behaviour and 3) barriers and facilitators to changing sedentary behaviour. CONCLUSIONS: Sedentary behaviour is multifaceted and influenced by a complex interaction between individual, environmental and socio-cultural factors. Micro and macro pressures are experienced at different life stages and in the context of illness; these shape individuals' beliefs and behaviour related to sedentariness. Knowledge of sedentary behaviour and the associated health consequences appears limited in adult populations, therefore there is a need for provision of accessible information about ways in which sedentary behaviour reduction can be integrated in people's daily lives. Interventions targeting a reduction in sedentary behaviour need to consider the multiple influences on sedentariness when designing and implementing interventions.
Asunto(s)
Promoción de la Salud/estadística & datos numéricos , Conducta Sedentaria , Adulto , Humanos , Investigación CualitativaRESUMEN
Neural tube defects (NTDs) affecting the brain (anencephaly) are lethal before or at birth, whereas lower spinal defects (spina bifida) may lead to lifelong neurological handicap. Collectively, NTDs rank among the most common birth defects worldwide. This study focuses on anencephaly, which despite having a similar frequency to spina bifida and being the most common type of NTD observed in mouse models, has had more limited inclusion in genetic studies. A genetic influence is strongly implicated in determining risk of NTDs and a molecular diagnosis is of fundamental importance to families both in terms of understanding the origin of the condition and for managing future pregnancies. Here we used a custom panel of 191 NTD candidate genes to screen 90 patients with cranial NTDs (n = 85 anencephaly and n = 5 craniorachischisis) with a targeted exome sequencing platform. After filtering and comparing to our in-house control exome database (N = 509), we identified 397 rare variants (minor allele frequency, MAF < 1%), 21 of which were previously unreported and predicted damaging. This included 1 frameshift (PDGFRA), 2 stop-gained (MAT1A; NOS2) and 18 missense variations. Together with evidence for oligogenic inheritance, this study provides new information on the possible genetic causation of anencephaly.
Asunto(s)
Anencefalia/genética , Epistasis Genética , Defectos del Tubo Neural/genética , Disrafia Espinal/genética , Anencefalia/fisiopatología , Animales , Modelos Animales de Enfermedad , Femenino , Estudios de Asociación Genética , Humanos , Masculino , Ratones , Mutación , Defectos del Tubo Neural/fisiopatología , Fenotipo , Embarazo , Cráneo/anomalías , Cráneo/fisiopatología , Disrafia Espinal/fisiopatología , Secuenciación del ExomaRESUMEN
OBJECTIVE: To map the current testing being undertaken following pregnancy loss across the UK and to examine the clinical utility in terms of identifying a cause for the loss and in identifying couples at risk of an unbalanced liveborn child. DESIGN: Retrospective audit. SETTING: UK, for the year 2014. POPULATION: An audit of 6465 referrals for genetic testing of tissue samples following pregnancy loss. METHODS: Data were obtained by questionnaire from 15 UK regional genetics laboratories. MAIN OUTCOME MEASURES: Data were analysed with respect to gestational age, the presence of identified fetal anomalies, methodologies used, abnormality rates and the presence of a parental balanced rearrangement. RESULTS: Of 6465 referrals a genetic cause was identified in 22% of cases (before 12 weeks' gestation, in 47%; at 12-24 weeks, in 14%; after 24 weeks, in 6%). In 0.4% of cases a balanced parental rearrangement was identified where there was a risk of an affected liveborn child in a future pregnancy. Eighty percent of genetic imbalances identified were aneuploidy or triploidy and could be identified by quantitative fluorescence polymerase chain reaction alone. There was significant variation across the UK in acceptance criteria, testing strategies and thus level of resolution of testing. CONCLUSIONS: Genetic testing of tissues following pregnancy loss identifies a probable cause of fetal demise in 22% of cases, but it is of low clinical utility in identifying couples at risk of a future unbalanced liveborn child. A comprehensive multidisciplinary review is needed to develop proposals for an affordable and equitable service. TWEETABLE ABSTRACT: UK audit of genetic testing of fetal loss shows variation in access to and resolution of analysis.
Asunto(s)
Aborto Espontáneo/genética , Pruebas Genéticas/métodos , Aborto Espontáneo/patología , Aneuploidia , Aberraciones Cromosómicas , Trastornos de los Cromosomas/diagnóstico , Trastornos de los Cromosomas/genética , Femenino , Feto/patología , Humanos , Auditoría Médica , Embarazo , Estudios Retrospectivos , Encuestas y Cuestionarios , Reino UnidoRESUMEN
Temporary and permanent tracheostomies are required in children to manage actual or anticipated long-term ventilatory support, to aid secretion management or to manage fixed upper airway obstruction. Tracheostomies may be required from the first few moments of life, with the majority performed in children < 4 years of age. Although similarities with adult tracheostomies are apparent, there are key differences when managing the routine and emergency care of children with tracheostomies. The National Tracheostomy Safety Project identified the need for structured guidelines to aid multidisciplinary clinical decision making during paediatric tracheostomy emergencies. These guidelines describe the development of a bespoke emergency management algorithm and supporting resources. Our aim is to reduce the frequency, nature and severity of paediatric tracheostomy emergencies through preparation and education of staff, parents, carers and patients.
Asunto(s)
Obstrucción de las Vías Aéreas , Servicios Médicos de Urgencia , Pediatría , Traqueostomía , Preescolar , Humanos , Lactante , Recién Nacido , Obstrucción de las Vías Aéreas/terapia , Urgencias Médicas , Servicios Médicos de Urgencia/métodos , Pediatría/métodos , Traqueostomía/métodosRESUMEN
BACKGROUND: It has been hypothesised that an 'activitystat' may biologically regulate energy expenditure or physical activity levels, thereby limiting the effectiveness of physical activity interventions. Using a randomised controlled trial design, the aim of this study was to investigate the effect of a six-week exercise stimulus on energy expenditure and physical activity, in order to empirically test this hypothesis. METHODS: Previously inactive adults (n = 129) [age (mean ± SD) 41 ± 11 year; body mass index 26.1 ± 5.2 kg/m(2)] were randomly allocated to a Control group (n = 43) or a 6-week Moderate (150 min/week) (n = 43) or Extensive (300 min/week) (n = 43) exercise intervention group. Energy expenditure and physical activity were measured using a combination of accelerometry (total counts, minutes spent in moderate to vigorous physical activity) and detailed time use recalls using the Multimedia Activity Recall for Children and Adults (total daily energy expenditure, minutes spent in moderate to vigorous physical activity) at baseline, mid- and end-intervention and 3- and 6-month follow up. Resting metabolic rate was measured at baseline and end-intervention using indirect calorimetry. Analysis was conducted using random effects mixed modeling. RESULTS: At end-intervention, there were statistically significant increases in all energy expenditure and physical activity variables according to both accelerometry and time use recalls (p < 0.001) in the Moderate and Extensive groups, relative to Controls. There was no significant change in resting metabolic rate (p = 0.78). CONCLUSION: Taken together, these results show no evidence of an "activitystat" effect. In the current study, imposed exercise stimuli of 150-300 min/week resulted in commensurate increases in overall energy expenditure and physical activity, with no sign of compensation in either of these constructs. TRIAL REGISTRATION NUMBER: ACTRN12610000248066 (registered prospectively 24 March 2010).
Asunto(s)
Metabolismo Energético/fisiología , Ejercicio Físico/fisiología , Promoción de la Salud/métodos , Acelerometría , Adulto , Retroalimentación , Femenino , Homeostasis , Humanos , Masculino , Persona de Mediana Edad , Resultado del TratamientoRESUMEN
The developing fetus is likely to be exposed to the same environmental chemicals as the mother during critical periods of growth and development. The degree of maternal-fetal transfer of chemical compounds will be affected by chemical and physical properties such as lipophilicity, protein binding, and active transport mechanisms that influence absorption and distribution in maternal tissues. However, these transfer processes are not fully understood for most environmental chemicals. This review summarizes reported data from more than 100 studies on the ratios of cord:maternal blood concentrations for a range of chemicals including brominated flame-retardant compounds, polychlorinated biphenyls (PCB), polychlorinated dibenzodioxins and dibenzofurans, organochlorine pesticides, perfluorinated compounds, polyaromatic hydrocarbons, metals, and tobacco smoke components. The studies for the chemical classes represented suggest that chemicals frequently detected in maternal blood will also be detectable in cord blood. For most chemical classes, cord blood concentrations were found to be similar to or lower than those in maternal blood, with reported cord:maternal ratios generally between 0.1 and 1. Exceptions were observed for selected brominated flame-retardant compounds, polyaromatic hydrocarbons, and some metals, for which reported ratios were consistently greater than 1. Careful interpretation of the data in a risk assessment context is required because measured concentrations of environmental chemicals in cord blood (and thus the fetus) do not necessarily imply adverse effects or risk. Guidelines and recommendations for future cord:maternal blood biomonitoring studies are discussed.
Asunto(s)
Contaminantes Ambientales/sangre , Sangre Fetal/química , Intercambio Materno-Fetal , Contaminantes Ambientales/química , Contaminantes Ambientales/metabolismo , Femenino , Humanos , Placenta/fisiología , EmbarazoAsunto(s)
Hospitales Pediátricos , Seguridad del Paciente , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/prevención & control , Centros de Atención Terciaria , Traqueostomía/efectos adversos , Niño , Humanos , Paquetes de Atención al Paciente , Guías de Práctica Clínica como Asunto , Estudios Retrospectivos , Traqueostomía/métodos , Reino UnidoRESUMEN
In Alligator mississippiensis the spinal dura is surrounded by a venous sinus; pressure waves can propagate in the spinal venous blood, and these spinal venous pressures can be transmitted to the spinal cerebrospinal fluid (CSF). This study was designed to explore pressure transfer between the spinal venous blood and the spinal CSF. At rest the cardiac-related CSF pulsations are attenuated and delayed, while the ventilatory-related pulsations are amplified as they move from the spinal venous blood to the spinal CSF. Orthostatic gradients resulted in significant alterations of both cardiac- and ventilatory-related CSF pulsations. Manual lateral oscillations of the alligator's tail created pressure waves in the spinal CSF that propagated, with slight attenuation but no delay, to the cranial CSF. Oscillatory pressure pulsations in the spinal CSF and venous blood had little influence on the underlying ventilatory pulsations, though the same oscillatory pulsations reduced the ventilatory- and increased the cardiac-related pulsations in the cranial CSF. In Alligator the spinal venous anatomy creates a more complex pressure relationship between the venous and CSF systems than has been described in humans.
Asunto(s)
Presión del Líquido Cefalorraquídeo , Duramadre , Humanos , Presión Venosa , Líquido Cefalorraquídeo/fisiología , Presión Sanguínea/fisiologíaRESUMEN
BACKGROUND: The concept of benefit sharing to enhance the social value of global health research in resource poor settings is now a key strategy for addressing moral issues of relevance to individuals, communities and host countries in resource poor settings when they participate in international collaborative health research.The influence of benefit sharing framework on the conduct of collaborative health research is for instance evidenced by the number of publications and research ethics guidelines that require prior engagement between stakeholders to determine the social value of research to the host communities. While such efforts as the production of international guidance on how to promote the social value of research through such strategies as benefit sharing have been made, the extent to which these ideas and guidelines have been absorbed by those engaged in global health research especially in resource poor settings remains unclear. We examine this awareness among stakeholders involved in health related research in Kenya. METHODS: We conducted in-depth interviews with key informants drawn from within the broader health research system in Kenya including researchers from the mainstream health research institutions, networks and universities, teaching hospitals, policy makers, institutional review boards, civil society organisations and community representative groups. RESULTS: Our study suggests that although people have a sense of justice and the moral aspects of research, this was not articulated in terms used in the literature and the guidelines on the ethics of global health research. CONCLUSION: This study demonstrates that while in theory several efforts can be made to address the moral issues of concern to research participants and their communities in resource poor settings, quick fixes such as benefit sharing are not going to be straightforward. We suggest a need to pay closer attention to the processes through which ethical principles are enacted in practice and distil lessons on how best to involve individuals and communities in promoting ethical conduct of global health research in resource poor settings.
Asunto(s)
Investigación Biomédica , Participación de la Comunidad , Conducta Cooperativa , Países en Desarrollo , Ética en Investigación , Justicia Social , Academias e Institutos , Concienciación , Participación de la Comunidad/tendencias , Comprensión , Países en Desarrollo/economía , Comités de Ética en Investigación , Política de Salud/tendencias , Recursos en Salud , Necesidades y Demandas de Servicios de Salud/tendencias , Hospitales de Enseñanza , Humanos , Kenia , Narración , Organizaciones , Investigación Cualitativa , Relaciones Investigador-Sujeto/ética , Valores Sociales , Encuestas y Cuestionarios , UniversidadesRESUMEN
Microstructural characterisation of neutron irradiated low alloy steels is important for developing mechanistic understanding of irradiation embrittlement. This work is focused on the early stages of irradiation-induced clustering in a low Cu (0.03wt%), high Ni ( approximately 1wt%) weld. The weld was irradiated at a very high dose rate and then examined by atom probe (energy-compensated position-sensitive atom probe (ECOPoSAP) and local electrode atom probe (LEAP)) with supporting microstructural information obtained by small angle neutron scattering (SANS) and positron annihilation (PALA). It was demonstrated that extreme care must be taken optimising parameters used to characterise the extent of clustering. This is particularly important during the early stages of irradiation-damage when the clusters are poorly defined and significant compositional variations are present in what is traditionally described as matrix. Analysis of the irradiated materials showed increasing clustering of Cu, Mn, Ni and Si with dose. In the low Cu steel the results showed that initially the irradiation damage results in clustering of Mn, Ni and Si, but at very high doses, at very high dose rates, redistribution of Si is significantly more advanced than that for Mn and Ni.
RESUMEN
INTRODUCTION: Inflammatory myofibroblastic tumours (IMTs), are uncommon tumours which can act with malignant potential. The management of these tumours can be extremely problematic but are often referred to surgical multi-disciplinary team meetings with the intention of surgical and oncological management (Chaudhary [1]). CASE REPORT: A 69-year-old gentleman was admitted with a 2-day history of abdominal pain and vomiting, and a 4-day history of absolute constipation. CT Abdomen Pelvis demonstrated distended loops of small bowel with pronounced fluid levels but no transition point. Intra-operative findings showed a right ileocolic mass adherent to the pelvic side wall and omental caking. Biopsies showed a florid myofibroblastic reaction, not a malignant process. CONCLUSION: IMTS are aggressive lesions but metastases is rare. Abdominal IMTS are difficult to diagnose and manage as they are often initially mistaken for lymphoma or peritoneal metastases. The therapy of choice is surgical resection of the tumour (Firat et al. [3]).
RESUMEN
BACKGROUND: A 2010 meta-analysis of internet-delivered CBT (iCBT) RCTs argued 'computer therapy for the anxiety and depressive disorders was effective, acceptable and practical health care' without data on effectiveness or practicality in routine practice. METHODS: Databases, reviews and meta-analyses were searched for randomised controlled trials of cCBT or iCBT versus a control group (care as usual, waitlist, information control, psychological placebo, pill placebo, etc.) in people who met diagnostic criteria for major depression, panic disorder, social anxiety disorder or generalised anxiety disorder. Number randomised, superiority of treatment versus control (Hedges'g) on primary outcome measure, length of follow-up, follow up outcome, patient adherence and satisfaction/harm were extracted; risk of bias was assessed. A search for studies on effectiveness of iCBT in clinical practice was conducted. RESULTS: 64 trials were identified. The mean effect size (efficacy) was gâ¯=â¯0.80 (NNT 2.34), and benefit was evident across all four disorders. Improvement was maintained at follow-with good acceptability. Research probity was good, and bias risk low. In addition, nine studies comparing iCBT with traditional face-to-face CBT and three comparing iCBT with bibliotherapy were identified. All three modes of treatment delivery appeared equally beneficial. The results of effectiveness studies were congruent with the results of the efficacy trials. LIMITATIONS: Studies variably measured changes in quality of life and disability, and the lack of comparisons with medications weakens the field. CONCLUSIONS: The conclusions drawn in the original meta-analysis are now supported: iCBT for the anxiety and depressive disorders is effective, acceptable and practical health care.
Asunto(s)
Trastornos de Ansiedad/terapia , Terapia Cognitivo-Conductual , Trastorno Depresivo/terapia , Internet , Cooperación del Paciente , Satisfacción Personal , Terapia Asistida por Computador , Adulto , Trastornos de Ansiedad/psicología , Trastorno Depresivo/psicología , Humanos , Masculino , Calidad de VidaRESUMEN
BACKGROUND: Complete heart block (CHB) is a major complication that occurs after congenital heart surgery. We hypothesized that genetic and clinical factors are associated with the development of postoperative CHB and recovery of atrioventricular (AV) conduction. OBJECTIVE: The purpose of this study was to identify predictors of CHB and recovery after congenital heart surgery. METHODS: Patients undergoing congenital heart surgery at our institution from September 2007 through June 2015 were prospectively enrolled in a parent study of postoperative arrhythmias. Patients with onset of CHB within 48 hours postoperatively were included in the study. Daily rhythm assessment was performed until demonstration of 1:1 conduction or pacemaker implantation. RESULTS: Of 1199 subjects enrolled, 56 (4.7%) developed postoperative CHB. In multivariate analysis, preoperative digoxin exposure (odds ratio [OR] 2.4, 95% confidence interval [CI] 1.3-4.4), aortic cross-clamp time (OR 1.08, 95% CI 1.04-1.11), ventricular septal defect closure (OR 2.2, 95% CI 1.2-4.1), and a common polymorphism in the gene encoding connexin-40 (GJA5 rs10465885 TT genotype; OR 2.1, 95% CI 1.2-3.8) were independently associated with postoperative CHB. Junctional acceleration (JA) (OR 4.0, 95% CI 1.1-15.1) and intermittent conduction noted during complete AV block (OR 9.1, 95% CI 1.0-80) were independently associated with 1:1 AV conduction recovery. Use of a multivariate model including both JA and intermittent conduction demonstrated good discrimination with a positive predictive value of 86% (95% CI 67%-96%) in predicting 1:1 conduction recovery. CONCLUSION: Preoperative factors, including a missense polymorphism in GJA5, are independently associated with increased risk for CHB. JA and intermittent conduction may prove useful in predicting recovery of AV conduction among patients with CHB after congenital heart surgery.
Asunto(s)
Bloqueo Atrioventricular , Procedimientos Quirúrgicos Cardíacos , Conexinas/genética , Cardiopatías Congénitas , Complicaciones Posoperatorias , Bloqueo Atrioventricular/diagnóstico , Bloqueo Atrioventricular/etiología , Bloqueo Atrioventricular/genética , Bloqueo Atrioventricular/prevención & control , Procedimientos Quirúrgicos Cardíacos/efectos adversos , Procedimientos Quirúrgicos Cardíacos/métodos , Preescolar , Femenino , Sistema de Conducción Cardíaco/fisiopatología , Cardiopatías Congénitas/diagnóstico , Cardiopatías Congénitas/genética , Cardiopatías Congénitas/fisiopatología , Cardiopatías Congénitas/cirugía , Humanos , Lactante , Masculino , Mutación Missense , Polimorfismo de Nucleótido Simple , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/genética , Complicaciones Posoperatorias/prevención & control , Valor Predictivo de las Pruebas , Pronóstico , Recuperación de la Función , Proteína alfa-5 de Unión ComunicanteRESUMEN
OBJECTIVE: This study aimed to evaluate the preliminary effectiveness and feasibility of a theory-informed program to reduce sitting time in older adults. DESIGN: Pre-experimental (pre-post) study. Thirty non-working adult (≥ 60 years) participants attended a one hour face-to-face intervention session and were guided through: a review of their sitting time; normative feedback on sitting time; and setting goals to reduce total sitting time and bouts of prolonged sitting. Participants chose six goals and integrated one per week incrementally for six weeks. Participants received weekly phone calls. OUTCOME MEASURES: Sitting time and bouts of prolonged sitting (≥ 30 min) were measured objectively for seven days (activPAL3c inclinometer) pre- and post-intervention. During these periods, a 24-h time recall instrument was administered by computer-assisted telephone interview. Participants completed a post-intervention project evaluation questionnaire. Paired t tests with sequential Bonferroni corrections and Cohen's d effect sizes were calculated for all outcomes. RESULTS: Twenty-seven participants completed the assessments (71.7 ± 6.5 years). Post-intervention, objectively-measured total sitting time was significantly reduced by 51.5 min per day (p=0.006; d=-0.58) and number of bouts of prolonged sitting by 0.8 per day (p=0.002; d=-0.70). Objectively-measured standing increased by 39 min per day (p=0.006; d=0.58). Participants self-reported spending 96 min less per day sitting (p<0.001; d=-0.77) and 32 min less per day watching television (p=0.005; d=-0.59). Participants were highly satisfied with the program. CONCLUSION: The 'Small Steps' program is a feasible and promising avenue for behavioral modification to reduce sitting time in older adults.
Asunto(s)
Objetivos , Promoción de la Salud/métodos , Actividad Motora , Conducta Sedentaria , Actigrafía , Anciano , Anciano de 80 o más Años , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Satisfacción del Paciente , Factores de TiempoRESUMEN
A male homosexual (positive for the human immunodeficiency virus) with a recent cat scratch developed fever, epitrochlear and axillary lymphadenopathy, and retinitis. Subsequently, he developed skin (epitheloid hemangioma) and mucosal lesions (Kaposi's sarcoma), multiple liver abscesses, and pleural effusion. Warthin-Starry stains and/or electron micrographs of lymph nodes and skin lesions demonstrated bacilli characteristic of those associated with cat-scratch disease. Cultures of lymph node, pleural fluid, and liver abscess specimens yielded organisms believed to be the causative agent of cat-scratch disease. We believe that disseminated cat-scratch disease may become an indicator of opportunistic infection signaling acquired immunodeficiency syndrome in a patient who is positive for the human immunodeficiency virus.
Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/complicaciones , Enfermedad por Rasguño de Gato/etiología , Adulto , Enfermedad por Rasguño de Gato/diagnóstico , Humanos , MasculinoRESUMEN
The effectiveness of 6-[18F]fluoro-L-m-tyrosine (6FMT) to evaluate dopamine presynaptic integrity was compared to that of 6-[18F]fluoro-L-dopa (6FDOPA) in vivo by positron emission tomography (PET). Six normal and six 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned monkeys received 6FDOPA and 6FMT PET scans on separate occasions with identical scanning protocols. Four measures, the rate of uptake of tracer into striatum using either the arterial input function (Ki) or the activity in the occipital cortex as the input function (Kc), the rate of loss of striatal radioactivity (k(loss)), and an index of "effective turnover" of dopamine (k(loss)/Ki), were obtained for both tracers during extended PET studies. 6-[18F]Fluoro-L-m-tyrosine was as effective as 6FDOPA in separating normals from MPTP-lesioned subjects on the basis of the uptake rate constants Ki and Kc. However, in contrast to 6FDOPA, it was not possible to differentiate the normal from the lesioned animal using k(loss) or k(loss)/Ki for 6FMT. Thus, FMT appears to be a reasonable, highly specific tracer for studying the activity of aromatic dopa decarboxylase enzyme as an index of presynaptic integrity. However, if one is interested in investigating further the metabolic pathway and obtaining an in vivo estimate of the effective turnover of dopamine (after pharmacologic manipulation, for example), 6FDOPA remains the tracer of choice.
Asunto(s)
Dihidroxifenilalanina/análogos & derivados , Dopamina/fisiología , Sinapsis/fisiología , Tirosina/análogos & derivados , Animales , Cromatografía Líquida de Alta Presión , Cuerpo Estriado/metabolismo , Dihidroxifenilalanina/farmacocinética , Dopa-Decarboxilasa/metabolismo , Radioisótopos de Flúor , Macaca fascicularis , Macaca mulatta , Lóbulo Occipital/metabolismo , Tomografía Computarizada de Emisión , Tirosina/farmacocinéticaRESUMEN
OBJECTIVE: The authors tested the hypothesis that the regional distribution of cerebral vasculature is anomalous in schizophrenia. METHOD: Dynamic susceptibility contrast magnetic resonance imaging was used to evaluate cerebral blood volume in the right and left occipital cortex, basal ganglia, and cerebellum of 10 subjects with schizophrenia and 10 healthy comparison subjects. RESULTS: Cerebral blood volume was greater in the schizophrenic subjects in every region studied. CONCLUSIONS: The findings suggest an abnormality of the configuration of cerebral blood vessels in schizophrenia.