Real-World Outcomes of Patients Starting Intravenous and Transitioning to Subcutaneous Vedolizumab in Inflammatory Bowel Disease.

BACKGROUND: Real-world data on starting intravenous (IV) vedolizumab (VDZ) and transitioning to subcutaneous (SC) treatment in inflammatory bowel disease (IBD) are scarce. AIMS: To assess treatment outcomes of patients with IBD starting IV VDZ and switching to SC VDZ in routine clinical care. METHODS: Adult patients with IBD switching from IV to SC VDZ treatment between 1 March 2020 and 31 December 2021 were identified from the Swedish IBD quality register. The primary outcome was SC VDZ persistence. Secondary outcomes included clinical remission, changes in quality of life (QoL) according to EuroQual 5-Dimensions 5-Levels (EQ-5D-5L) and the Short-Health Scale (SHS) and inflammatory markers, including faecal Calprotectin (FCP). RESULTS: Altogether, 406 patients with IBD (Crohn's disease, n = 181; ulcerative colitis, n = 225) were identified. After a median follow-up of 30 months from starting IV VDZ treatment, the persistence rates were 98%(178/181) in Crohn's disease and 94% (211/225) in ulcerative colitis. Most patients (84%) transitioned during maintenance therapy, and the median follow-up from switch to SC VDZ was 10 months. Compared to baseline, statistically significant improvements were observed in all domains of the SHS, EQ-5D index value and visual analogue scale. Median (interquartile range) FCP concentrations (µg/g) decreased from 459 (185-1001) to 65 (26-227) in Crohn's disease (n = 45; p < 0.001) and from 646 (152-1450) to 49 (20-275) in ulcerative colitis (n = 58; p < 0.001). CONCLUSION: Initiating IV VDZ and switching to SC treatment was associated with high persistence rates and improvements in measures of QoL and FCP. These findings are reassuring for patients who start IV VDZ and switch to SC VDZ.

Prehospital stratification and prioritisation of non-ST-segment elevation acute coronary syndrome patients (NSTEACS): the MARIACHI scale.

OBJECTIVE: The objective of this study was to develop and validate a risk scale (MARIACHI) for patients classified as non-ST-segment elevation acute coronary syndrome (NSTEACS) in a prehospital setting with the ability to identify patients at an increased risk of mortality at an early stage. METHODS: A retrospective observational study conducted in Catalonia over two periods: 2015-2017 (development and internal validation cohort) and Aug 2018-Jan 2019 (external validation cohort). We included patients classified as prehospital NSTEACS, assisted by an advanced life support unit and requiring hospital admission. The primary outcome was in-hospital mortality. Cohorts were compared using logistic regression and a predictive model was created using bootstrapping techniques. RESULTS: The development and internal validation cohort included 519 patients. The model is composed of five variables associated with hospital mortality: age, systolic blood pressure, heart rate > 95 bpm, Killip-Kimball III-IV and ST depression ≥ 0.5 mm. The model showed good overall performance (Brier = 0.043) and consistency in discrimination (AUC 0.88, 95% CI 0.83-0.92) and calibration (slope = 0.91; 95% CI 0.89-0.93). We included 1316 patients for the external validation sample. There was no difference in discrimination (AUC 0.83, 95% CI 0.78-0.87; DeLong Test p = 0.071), but there was in calibration (p < 0.001), so it was recalibrated. The finally model obtained was stratified and scored into three groups according to the predicted risk of patient in-hospital mortality: low risk: < 1% (-8 to 0 points), moderate risk: 1-5% (+ 1 to + 5 points) and high risk: > 5% (6-12 points). CONCLUSION: The MARIACHI scale showed correct discrimination and calibration to predict high-risk NSTEACS. Identification of high-risk patients may help with treatment and low referral decisions at the prehospital level.

Infarto de miocardio con elevación del segmento ST revascularizado. Tendencias temporales de los tratamientos contemporáneos y su impacto en los resultados / Revascularized ST-segment elevation myocardial infarction. Temporal trends in contemporary therapies and impact on outcomes

Introducción y objetivos Evaluar en pacientes con infarto agudo de miocardio con elevación del segmento ST (IAMCEST) sometidos a angioplastia primaria con qué ritmo se ha introducido en la práctica clínica (2010-2017) los tratamientos con stents farmacoactivos, ticagrelor, prasugrel y antiagregante plaquetario doble (TAPD) prolongado y su potencial impacto en el resultado a 2 años. Métodos Análisis retrospectivo de un registro prospectivo exhaustivo de 14.841 pacientes con IAMCEST sometidos a angioplastia primaria entre 2010 y 2017. Los eventos índice se obtuvieron del Registro de Código IAM de Cataluña y los eventos en el seguimiento, del conjunto mínimo de datos de altas hospitalarias. Se definió el TAPD a partir de la dispensación farmacéutica. Se evaluó el resultado a 24 meses. Las tendencias temporales de los factores de exposición y los resultados se analizaron mediante modelos de regresión. Resultados La edad> 65 años, la diabetes, la insuficiencia renal, la insuficiencia cardiaca previa y la necesidad de anticoagulación al alta fueron más frecuentes en periodos más tardíos (p <0,001). Entre 2010 y 2017 el implante de stents farmacoactivos aumentó del 31,1 al 69,8%; la prescripción de ticagrelor, del 0,1 al 28,6% y la de prasugrel, del 1,5 al 23,8%, y la media de meses consecutivos con TAPD, de 2 a 10 (p <0,001 en todos los casos). El análisis ajustado mostró una tendencia temporal a disminución del riesgo de la variable de resultado principal: el evento compuesto de muerte, infarto agudo de miocardio, ictus y nueva revascularización (reducción absoluta de la probabilidad, el 0,005% por trimestre; OR=0,995; IC95%, 0,99-0,999; p=0,028). Todos los componentes individuales excepto el ictus mostraron una reducción de la probabilidad, solo significativa para la aparición de nueva revascularización (AU)

Introduction and objectives To assess, in patients with ST-segment elevation myocardial infarction (STEMI) who underwent primary percutaneous intervention, the pace of introduction in clinical practice (2010-2017) of drug-eluting stents (DES), ticagrelor, prasugrel, and prolonged dual antiplatelet therapy (DAPT) duration, and their potential impact on the risk of 2-year outcomes. Methods Prospective and exhaustive community-wide cohort of 14 841 STEMI patients undergoing primary percutaneous intervention between 2010 and 2017. Index episodes were obtained from the Catalan Codi IAM Registry, events during follow-up from the Minimum Data Set and DAPT were defined by pharmacy dispensation. Follow-up was 24 months. The temporal trend for exposures and outcomes was assessed using regression models. Results Age> 65 years, diabetes, renal failure, previous heart failure, and need for anticoagulation at discharge were more frequent in later periods (P <.001). From 2010 to 2017, the use of DES increased from 31.1% to 69.8%, ticagrelor from 0.1% to 28.6%, prasugrel from 1.5% to 23.8%, and the median consecutive months on DAPT from 2 to 10 (P <.001 for all). Adjusted analysis showed a temporal trend to a lower risk of the main outcome over time: the composite of death, acute myocardial infarction, stroke and repeat revascularization (absolute odds reduction 0.005% each quarter; OR, 0.995; 95%CI, 0.99-0.999; P=.028). The odds of all individual components except stroke were reduced, although significance was only reached for revascularization. Conclusions Despite a strong increase between 2010 and 2017 in the use and duration of DAPT and the use of ticagrelor, prasugrel and DES, there was no substantial reduction in major cardiovascular outcomes (AU)

Análisis del temperamento infantil relacionado con el uso de pantallas / Analysis of infant temperament related to screen use

Introducción: el objetivo del estudio fue describir el tiempo de uso de pantallas y relacionarlo con los rasgos temperamentales y del comportamiento del niño. Material y métodos: estudio observacional descriptivo mediante cuestionario estructurado entregado a los progenitores para saber el tiempo de exposición de su hijo/a a las pantallas y valoración del temperamento infantil con el cuestionario Emotionality Sociability and Activity Temperament (EAS) de niños con edades comprendidas entre 0 y 10 años del centro de salud Revolería y Torrero-La Paz de Zaragoza (España) durante los meses de junio de 2019 hasta febrero de 2020. El estudio fue aprobado por el Comité de Ética e Investigación de la Comunidad Autónoma de Aragón (PI 19/00260). Resultados: participación de 212 niños. El 54,1% fueron niñas. Edad media: 5,3±2,7 años; peso medio: 21,2±9,6 kg; talla media: 1,11±0,20 m; el 62,9% se clasificó en peso normal. Un 76,1% realiza ejercicio físico. Edad de inicio a la exposición a las pantallas: el 39,0% fue con una edad superior a 24 meses; el 42,4% se expone un tiempo medio de 60-120 minutos al uso de pantallas. Evaluación del temperamento infantil con la escala EAS (sociabilidad: 18,1±3,1; actividad 19,0±4,2; emocionalidad 13,9±4,0 y timidez: 12,3±4,1). Conclusiones: en la muestra estudiada, los niños con edades superiores presentaron un tiempo mayor de uso a la exposición y uso de pantallas. No se hallaron diferencias significativas entre el tiempo de uso de las pantallas y los cambios del temperamento infantil (AU)

Introduction: the aim of this study was to describe the screen time in children and analyse its association with personality traits and behaviour.Methods: observational and descriptive study through a structured, self-administered questionnaire completed by parents to assess screen time in their children and the Emotionality, Activity and Sociability (EAS) questionnaire to assess traits and behaviours in children aged 0 to 10 years in the caseloads of the Revolería and Torrero-La Paz primary care centres in Zaragoza (Spain) between June 2019 and February 2020. Research Ethics Committee of the Autonomous Community of Aragón (PI 19/00260).Results: the sample included 212 children, 54.1% female. The mean age was 5.3 ± 2.7 years; the mean weight 21.2 ± 9.6 kg, the mean height 1.1 ± 0.2 m, and 62.9% had a normal weight. Of the total, 76.1% reported physical activity. The age at which exposure to screens started was greater than 24 months in 39%; and 42.4% used screens between 60 and 120 minutes on average. The assessment of traits with the EAS survey yielded the following mean scores: sociability, 18.1 ± 3.1; activity, 19.0 ± 4.2; emotionality, 13.9 ± 4.04; shyness, 12.3 ± 4.1.Conclusion: in the sample under study, screen time and use were greater in older children. There were no statistically significant differences in screen time associated with differences in temperament. (AU)

Incidence of diabetes mellitus and associated risk factors in the adult population of the Basque country, Spain.

The aim of this study was to estimate the incidence of diabetes mellitus in the Basque Country and the risk factors involved in the disease by reassessing an adult population after 7 years of follow-up. In the previous prevalence study, 847 people older than 18 years were randomly selected from all over the Basque Country and were invited to answer a medical questionnaire, followed by a physical examination and an oral glucose tolerance test. In the reassessment, the same variables were collected and the resulting cohort comprised 517 individuals of whom 43 had diabetes at baseline. The cumulative incidence of diabetes was 4.64% in 7 years and the raw incidence rate was 6.56 cases/1000 person-years (95%CI: 4.11-9.93). Among the incident cases, 59% were undiagnosed. The most strongly associated markers by univariate analyses were age > 60 years, dyslipidaemia, prediabetes and insulin resistance. We also found association with hypertension, obesity, family history of diabetes and low education level. Multivariate analysis adjusted for age and sex showed that a set of risk factors assessed together (dyslipidaemia, waist-to-hip-ratio and family history of diabetes) had great predictive value (AUC-ROC = 0.899, 95%CI: 0.846-0.953, p = 0.942), which suggests the need for early intervention before the onset of prediabetes.

[Comorbidity in mental health in patients diagnosed with chronic obstructive pulmonary disease]. / La comorbilidad en salud mental en los pacientes diagnosticados de enfermedad pulmonar obstructiva crónica.

OBJECTIVE: Anxiety and depression play an important role in chronic obstructive pulmonary disease, although there are a limited number of studies that have attempted to determine their relationship with exacerbations, and even less have tried to quantify the number of associated exacerbations. The aim of this study was to determine the risk of exacerbations associated with anxiety and depression in patients diagnosed with chronic obstructive pulmonary disease. MATERIAL AND METHODS: A prospective cohort study was conducted that analysed the factors associated with exacerbations in 512 patients over a 2-year period. The exacerbations that required antibiotics and/or systemic corticosteroids were defined as moderate, and those that required hospital admission, as severe. The Hospital Anxiety and Depression Scale was applied to each patient, and the number of exacerbations during follow-up were quantified. RESULTS: The prevalence of anxiety/depression at the beginning of the study was 15.6%. During the 2 years of follow-up, the mean number of exacerbations was 2.21. The patients that also had anxiety/depression at the beginning of the study had a higher mean number of exacerbations (2.8; P=.001). Anxiety/depression was associated with an increased number of moderate-severe exacerbations in the adjusted analysis (IRRa=1.48). The other risk factors associated with a higher mean number of exacerbations were, a history of a previous severe exacerbation (IRRa=1.50; obesity (IRRa=1.27); overweight (IRRa=1.23); FEV1 ≤ 77% (IRRa=0.84); and more dyspnoea (IRRa=1.14). CONCLUSIONS: Patients with anxiety/depression have a greater number of exacerbations, and have a 48% higher risk of suffering an exacerbation compared to those with chronic obstructive pulmonary disease with no anxiety/depression.

Cross-sectional study of the association between empathy and burnout and drug prescribing quality in primary care.

OBJECTIVE: The aim of this study was to assess whether burnout and empathy levels among general practitioners (GPs) might influence prescribing performance assessed using pharmaceutical prescription quality standard indicators. DESIGN AND SETTING: Cross-sectional descriptive study of 108 GPs from 22 primary care centers in Lleida, Spain, and of centralized data corresponding to 183 600 patients under their care. The study was conducted between May and July 2014. MAIN OUTCOME MEASURES: Burnout and empathy were measured using the Spanish versions of the Maslach Burnout Inventory and the Jefferson Scale for Physician Empathy, and prescribing quality was measured using the Catalan Pharmaceutical Prescription Quality Standard (EQPF). Normal distribution of scores was verified using the Chi-square and Kolmogorov-Smirnov-Lilliefors tests. The effect of each of the variables was evaluated using crude odds ratios. RESULTS: Older GPs scored significantly higher in the EQPF (P < 0.05). High empathy scores were positively associated with high EQPF scores. GPs with low burnout also performed better in the EQPF. CONCLUSIONS: More empathic, less burned-out, older GPs showed better prescribing performance according to quality indicators. However, further studies are needed to evaluate other factors influencing prescribing habits. The promotion of communication skills may increase empathy and reduce burnout, thus benefiting patients.

A pragmatic approach for mortality prediction after surgery in infective endocarditis: optimizing and refining EuroSCORE.

OBJECTIVE: To simplify and optimize the ability of EuroSCORE I and II to predict early mortality after surgery for infective endocarditis (IE). METHODS: Multicentre retrospective study (n = 775). Simplified scores, eliminating irrelevant variables, and new specific scores, adding specific IE variables, were created. The performance of the original, recalibrated and specific EuroSCOREs was assessed by Brier score, C-statistic and calibration plot in bootstrap samples. The Net Reclassification Index was quantified. RESULTS: Recalibrated scores including age, previous cardiac surgery, critical preoperative state, New York Heart Association >I, and emergent surgery (EuroSCORE I and II); renal failure and pulmonary hypertension (EuroSCORE I); and urgent surgery (EuroSCORE II) performed better than the original EuroSCOREs (Brier original and recalibrated: EuroSCORE I: 0.1770 and 0.1667; EuroSCORE II: 0.2307 and 0.1680). Performance improved with the addition of fistula, staphylococci and mitral location (EuroSCORE I and II) (Brier specific: EuroSCORE I 0.1587, EuroSCORE II 0.1592). Discrimination improved in specific models (C-statistic original, recalibrated and specific: EuroSCORE I: 0.7340, 0.7471 and 0.7728; EuroSCORE II: 0.7442, 0.7423 and 0.7700). Calibration improved in both EuroSCORE I models (intercept 0.295, slope 0.829 (original); intercept -0.094, slope 0.888 (recalibrated); intercept -0.059, slope 0.925 (specific)) but only in specific EuroSCORE II model (intercept 2.554, slope 1.114 (original); intercept -0.260, slope 0.703 (recalibrated); intercept -0.053, slope 0.930 (specific)). Net Reclassification Index was 5.1% and 20.3% for the specific EuroSCORE I and II. CONCLUSIONS: The use of simplified EuroSCORE I and EuroSCORE II models in IE with the addition of specific variables may lead to simpler and more accurate models.

Long-term outcome of infliximab treatment in chronic active ulcerative colitis: a Swedish multicentre study of 250 patients.

BACKGROUND: Real-life long-term data on infliximab treatment in ulcerative colitis are limited. AIM: To study the long-term efficacy and safety of infliximab in chronic active ulcerative colitis and possible predictors of colectomy and response were also examined. METHODS: A retrospective multi-centre study of infliximab treatment in 250 patients with chronic active ulcerative colitis with inclusion criteria: age ≥18 years, ambulatory treated, steroid-dependent or intolerant and/or immunomodulator refractory or intolerant. RESULTS: Steroid-free clinical remission was achieved by 123/250 patients (49.2%) at 12 months and in 126/250 patients at a median follow-up of 2.9 years (50.4%). Primary response at 3 months was achieved by 190/250 (76.0%) patients and associated with a high probability of response 168/190 (88.4%) at 12 months and 143/190 (75.3%) at follow-up. Long-term rate of colectomy in primary responders was 6/190 (3.2%) at 12 months and 27/190 (14.2%) at last follow-up. Failure to achieve response at 3 months was associated with a high risk of subsequent colectomy, 29/60 (48.3%) at 12 months and 41/60 (68.3%) at follow-up. Response at 12 months was associated with a low risk of subsequent colectomy, 14/181 (7.7%) compared with non-response 19/34 (55.9%) (P < 0.0001). Non-response at 3 months was an independent predictor of subsequent colectomy (HR = 9.40, 95% CI = 5.10-17.35, P < 0.001). Concomitant azathioprine therapy did not influence outcome in terms of colectomy. CONCLUSIONS: Long-term efficacy of infliximab treatment in chronic active ulcerative colitis is excellent especially in patients who respond to induction treatment. Conversely, non-response at 3 months predicts a poor outcome, with a high risk of subsequent colectomy.

Risk factors for exacerbation in chronic obstructive pulmonary disease: a prospective study.

BACKGROUND: Although acute exacerbations are key events in the progression of chronic obstructive pulmonary disease (COPD), their frequency and the factors associated with acute exacerbation are not fully known. OBJECTIVE: To determine the incidence and risk factors of very frequent exacerbations in COPD (⩾3 per year). PATIENTS AND METHODS: In a cohort study to analyse acute exacerbation and associated factors in 512 primary care patients during a 2-year follow-up, variables of interest were collected for each patient. Acute exacerbation was defined as an event that required antibiotics and/or systemic steroids (moderate) or hospital admission (severe). Odds ratios (OR) were used to determine factors associated with exacerbation. RESULTS: Incidence of exacerbation was 61.7% in the first year of follow-up and 63.9% in the second year. During the first year, the factors associated with very frequent exacerbation were previous hospital admission (OR 1.69), dyspnoea (moderate [OR 2.86] and severe-very severe [OR 5.83]) and the Charlson Index (OR 1.19); during the second year, associated factors were female sex (OR 4.17), history of previous hospital admissions (OR 2.90), smoking (smoker/ex-smoker) (OR 2.00) and forced vital capacity (OR 0.98). CONCLUSIONS: Incidence of exacerbation is high in COPD patients. Previous admission for exacerbation is a strong predictor and can identify patients at risk.

A major population of mucosal memory CD4+ T cells, coexpressing IL-18Rα and DR3, display innate lymphocyte functionality.

Mucosal tissues contain large numbers of memory CD4(+) T cells that, through T-cell receptor-dependent interactions with antigen-presenting cells, are believed to have a key role in barrier defense and maintenance of tissue integrity. Here we identify a major subset of memory CD4(+) T cells at barrier surfaces that coexpress interleukin-18 receptor alpha (IL-18Rα) and death receptor-3 (DR3), and display innate lymphocyte functionality. The cytokines IL-15 or the DR3 ligand tumor necrosis factor (TNF)-like cytokine 1A (TL1a) induced memory IL-18Rα(+)DR3(+)CD4(+) T cells to produce interferon-γ, TNF-α, IL-6, IL-5, IL-13, granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-22 in the presence of IL-12/IL-18. TL1a synergized with IL-15 to enhance this response, while suppressing IL-15-induced IL-10 production. TL1a- and IL-15-mediated cytokine induction required the presence of IL-18, whereas induction of IL-5, IL-13, GM-CSF, and IL-22 was IL-12 independent. IL-18Rα(+)DR3(+)CD4(+) T cells with similar functionality were present in human skin, nasal polyps, and, in particular, the intestine, where in chronic inflammation they localized with IL-18-producing cells in lymphoid aggregates. Collectively, these results suggest that human memory IL-18Rα(+)DR3(+) CD4(+) T cells may contribute to antigen-independent innate responses at barrier surfaces.

Targeting T-cell migration in inflammatory bowel disease.

Crohn's disease and ulcerative colitis are chronic inflammatory disorders of the gastrointestinal tract and are collectively referred to as inflammatory bowel disease (IBD). IBD is a major cause of lifetime morbidity, has a severe impact on quality of life of patients (equivalent to that of rheumatoid arthritis, asthma, migraine or diabetes) and constitutes a substantial economic burden to the healthcare system. The introduction of anti-tumour necrosis factor (TNF) antibodies has dramatically improved the treatment of IBD, but approximately one-third of patients are nonresponders and another 30-50% will eventually lose the therapeutic effect or become intolerant to these antibodies. Thus, there is an urgent and unmet need for new therapies. The aetiologies of the different forms of IBD have not been fully elucidated but there is strong evidence implicating T cells and T-cell migration to the gut in initiating and perpetuating the intestinal inflammatory process and tissue destruction. In recent years, progress in basic science has shed light on the mechanisms regulating T-cell migration to the gut and new therapeutics targeting these pathways have been developed. It is interesting that some of the factors directing the localization of T cells to the gut have been shown to be relatively organ specific, potentially enabling new T-cell-targeted treatments to demonstrate improved safety whilst preserving therapeutic efficacy. Here, fundamental aspects of the gut immune system, the generation of tissue-tropic effector T cells and the mechanisms of T-cell trafficking to the gut mucosa will be reviewed. In addition, the role of these processes in IBD and how they have been exploited for the development of novel therapies for IBD will be discussed.

The profile of general practitioners (GPs) who publish in selected family practice journals.

BACKGROUND: Providing support for research is one of the key issues in the ongoing attempts to improve Primary Care. However, when patient care takes up a significant part of a GP's time, conducting research is difficult. In this study we examine the working conditions and profile of GPs who publish in three leading medical journals and propose possible remedial policy actions. FINDINGS: The authors of all articles published in 2006 and 2007 in three international Family Medicine journals - Annals of Family Medicine, Family Practice, and Journal of Family Practice - were contacted by E-mail. They were asked to complete a questionnaire investigating the following variables: availability of specific time for research, time devoted to research, number of patients attended, and university affiliation. Only GPs were included in the study. Three hundred and ten relevant articles published between 2006 and 2007 were identified and the authors contacted using a survey tool. 124 researchers responded to our questionnaire; 45% of respondents who were not GPs were excluded. On average GPs spent 2.52 days per week and 6.9 hours per day on patient care, seeing 45 patients per week. Seventy-five per cent of GPs had specific time assigned to research, on average 13 hours per week; 79% were affiliated to a university and 69% held teaching positions. CONCLUSIONS: Most GPs who publish original articles in leading journals have time specifically assigned to research as part of their normal working schedule. They see a relatively small number of patients. Improving the working conditions of family physicians who intend to investigate is likely to lead to better research results.

Ionic dependence of the velocity of release of ATP from permeabilized cholinergic synaptic vesicles.

Evidence is provided to show that synaptic vesicles have an internal matrix. Suspensions of cholinergic synaptic vesicles isolated from the electric organ of Torpedo marmorata fish were permeabilized in solutions containing low concentrations of Na(+) or Ca(2+). The release of ATP from the vesicular matrix was 10 times more effective with Ca(2+) than with Na(+). We ascertained whether these two cations induced a different velocity of release of ATP from the matrix. The release of ATP was monitored with the chemiluminescent reaction of luciferin-luciferase. The light signal generated was the result of the kinetics of ATP release of the enzymatic reaction. To overcome the kinetics of the enzymatic reaction, the light records were deconvoluted. The actual kinetics of ATP release of vesicles containing Na(+) or Ca(2+) were coincident. To validate this result, comparison was made with ATP release from intact nerve terminals which were already deconvoluted. The results show that the real time course of release is longer than that obtained from synaptic vesicles. This was as expected given that the release of neurotransmitters is due to successive molecular steps of synaptic vesicle exocytosis.

The pharmacology of novel acetylcholinesterase inhibitors, (+/-)-huprines Y and X, on the Torpedo electric organ.

The effects of the tacrine-huperzine A hybrid acetylcholinesterase inhibitors, (+/-)-12-amino-3-chloro-9-methyl-6,7,10,11-tetrahydro-7,11-methanocycloocta[b]quinoline hydrochloride ((+/-)-huprine Y) and (+/-)-12-amino-3-chloro-9-ethyl-6,7,10,11-tetrahydro-7,11-methanocycloocta[b]quinoline hydrochloride ((+/-)-huprine X), were tested on spontaneous synaptic activity by measuring the amplitude, the rise time, the rate of rise, the half-width and the area or the electrical charge of the miniature endplate potentials (m.e.p.ps) recorded extracellularly on Torpedo electric organ fragments. (+/-)-Huprine Y and (+/-)-huprine X at a concentration of 500 nM increased all the m.e.p.p. variables analyzed. The effect of (+/-)-huprine Y was smaller than that of (+/-)-huprine X for all the variables except for the rate of rise where there was no significant difference. The effects of these drugs were also tested on nicotinic receptors by analyzing the currents elicited by acetylcholine (100 microM) in Xenopus laevis oocytes, transplanted with membranes from Torpedo electric organ. Both drugs inhibited the currents in a reversible manner, (+/-)-huprine Y (IC(50)=452 nM) being more effective than (+/-)-huprine X (IC(50)=4865 nM). The Hill coefficient was 0.5 for both drugs. The inhibition of the nicotinic receptor was voltage-dependent and decreased at depolarizing potentials, and there was no significant difference in the effects between (+/-)-huprine Y and (+/-)-huprine X at concentrations near to their IC(50) values. At depolarizing potentials between -20 and +15 mV, these drugs did not have any detectable effect on the blockade of the nicotinic receptor. Both huprines increased the desensitization of the nicotinic receptors since the current closed quickly in the presence of the drugs, and there was no significant difference in this effect between (+/-)-huprine Y (500 nM) and (+/-)-huprine X (5 microM). We conclude that (+/-)-huprine Y and (+/-)-huprine X increase the level of acetylcholine in the synaptic cleft more effectively than tacrine. The interaction of (+/-)-huprine X with nicotinic receptors is weaker than that of (+/-)-huprine Y, suggesting that (+/-)-huprine X would be more specific to maintain the extracellular acetylcholine concentration.

Effects of bis(7)-tacrine on spontaneous synaptic activity and on the nicotinic ACh receptor of Torpedo electric organ.

Bis(7)-tacrine is a potent acetylcholinesterase inhibitor in which two tacrine molecules are linked by a heptylene chain. We tested the effects of bis(7)-tacrine on the spontaneous synaptic activity. Miniature endplate potentials (MEPPs) were recorded extracellularly on slices of electric organ of Torpedo marmorata. Bis(7)-tacrine, at a concentration of 100 nM, increased the magnitudes that describe MEPPs: amplitude, area, rise time, rate of rise, and half-width. We also tested the effect of bis(7)-tacrine on nicotinic acetylcholine receptors by analyzing the currents elicited by acetylcholine (100 microM) in Torpedo electric organ membranes transplanted in Xenopus laevis oocytes. Bis(7)-tacrine inhibited the acetylcholine-induced currents in a reversible manner (IC(50) = 162 nM). The inhibition of nicotinic acetylcholine receptors was not voltage dependent, and bis(7)-tacrine increased the desensitization of nicotinic acetylcholine receptors. The Hill coefficient for bis(7)-tacrine was -0.72 +/- 0.02, indicating that bis(7)-tacrine binds to the nicotinic acetylcholine receptor in a molecular ratio of 1:1, but does not affect the binding of alpha-bungarotoxin with the nicotinic acetylcholine receptor. In conclusion, bis(7)-tacrine greatly increases the spontaneous quantal release from peripheral cholinergic terminals at a much lower concentration than tacrine. Bis(7)-tacrine also blocks acetylcholine-induced currents of Torpedo electric organ, although the mechanism is different from that of tacrine: bis(7)-tacrine enhances desensitization, whereas tacrine reduces it.

ATP crossing the cell plasma membrane generates an ionic current in xenopus oocytes.

The presence of ATP within cells is well established. However, ATP also operates as an intercellular signal via specific purinoceptors. Furthermore, nonsecretory cells can release ATP under certain experimental conditions. To measure ATP release and membrane currents from a single cell simultaneously, we used Xenopus oocytes. We simultaneously recorded membrane currents and luminescence. Here, we show that ATP release can be triggered in Xenopus oocytes by hyperpolarizing pulses. ATP release (3.2 +/- 0.3 pmol/oocyte) generated a slow inward current (2.3 +/- 0.1 microA). During hyperpolarizing pulses, the permeability for ATP(4-) was more than 4000 times higher than that for Cl(-). The sensitivity to GdCl(3) (0. 2 mm) of hyperpolarization-induced ionic current, ATP release and E-ATPase activity suggests their dependence on stretch-activated ion channels. The pharmacological profile of the current inhibition coincides with the inhibition of ecto-ATPase activity. This enzyme is highly conserved among species, and in humans, it has been cloned and characterized as CD39. The translation, in Xenopus oocytes, of human CD39 mRNA encoding enhances the ATP-supported current, indicating that CD39 is directly or indirectly responsible for the electrodiffusion of ATP.