RESUMEN
SARS-CoV2 es causante del síndrome respiratorio agudo severo, enfermedad que ha sido también nombrada COVID-19, fue notificado a fines del año 2019 como un nuevo betacoronavirus en personas expuestas en un mercado de mariscos en Wuhan, China. El virus desde esa fecha se ha ido propagando rápidamente provocando una pandemia, y afectando a diversos países en mayor o menor magnitud. Actualmente existe información variada difundida sobre el virus y la enfermedad; los conocimientos sobre la fisiopatología y la manera en la que debe ser gestionada esta entidad han ido cambiando a través de tiempo. A pesar del interés que se ha generado en los mecanismos fisiopatológicos de la enfermedad y sus complicaciones, estos no se han llegado a descifrar totalmente. Mediante el presente artículo se hace una revisión sistematizada de la estructura, replicación y aspectos fisiopatológicos relacionados con SARS-CoV2, que ha provocado un elevado índice de morbimortalidad en la población a nivel mundial.
SARS-CoV2, which causes severe acute respiratory syndrome, also called COVID-19, was reported in late 2019 as a new betacoronavirus in exposed persons in a seafood market in Wuhan, China. The virus has since spread rapidly, causing a pandemic, affecting several countries to a greater or lesser extent. Currently, there is a variety of information disseminated about the virus and the disease; knowledge about the physiopathology and how it should be managed has changed over time. Despite the interest that has been generated in the physiopathological mechanisms of the disease and its complications, these have not been completely deciphered. The present article makes a systematized review of the structure, replication and physiopathological aspects related to SARS-CoV2, which has caused a high rate of morbimortality in the population worldwide.
Asunto(s)
Virus , Pandemias , Infecciones por Coronavirus , Betacoronavirus , SARS-CoV-2RESUMEN
PURPOSE: Obesity has been associated with reduced vagal function and increased sympathetic activity. Cardiac autonomic dysfunction has emerged as a major risk factor in the development of cardiovascular disease. Cardiac autonomic function (CAF) can be assessed by heart rate variability (HRV), an independent predictor of mortality based on changes in time intervals between adjacent heartbeats (RR). Bariatric surgery is considered the most effective treatment for obesity and its comorbidities, with sleeve gastrectomy (SG) being the most frequent bariatric procedure. There are few studies on HRV changes in women with obesity after SG. The aim of this study was to evaluate the short-term impact of SG on CAF and its relationship with weight loss. MATERIALS AND METHODS: An observational cohort study was conducted. Twenty-three female patients were assessed before SG and at 1 and 3 months after surgery. CAF was evaluated by analyzing HRV from 5-min records of RR intervals while the subject was supine. HRV was analyzed in time and frequency domains and with a nonlinear method. RESULTS: Patients (36.0 ± 11.1 years old, BMI 35.1 ± 3.4 kg/m2) presented higher HRV values, on average, in all domains both at 1 and 3 months after SG (p < 0.05). In addition, all anthropometric parameters improved (p < 0.001) although there was no relationship between HRV improvements and anthropometric changes. CONCLUSION: SG seems to be effective at reducing excess weight and improving HRV at the short term, and these changes are detectable as early as the first month after surgery. HRV assessment appears as a promising low-cost tool that deserves further research.
Asunto(s)
Cirugía Bariátrica , Obesidad Mórbida , Adulto , Femenino , Gastrectomía , Frecuencia Cardíaca , Humanos , Persona de Mediana Edad , Obesidad/cirugía , Obesidad Mórbida/cirugía , Resultado del Tratamiento , Adulto JovenRESUMEN
Resumen El virus SARS-CoV-2 se ha extendido a nivel mundial, rápidamente ha sobrecargado los sistemas de salud. Esta emergencia ha implicado cambios en la atención usual del infarto agudo miocardio con elevación del ST (IAMCEST) puesto que la actividad habitual de las salas de hemodinamia y las vías de traslado de los pacientes se ha visto afectada. La afectación del personal de salud también es una preocupación relevante por lo que presentamos un documento de Consenso de la Asociación Costarricense de Cardiología que pretende generar una guía de trabajo al personal que atiende esta patología y garantizar la atención adecuada del IAMCEST durante la pandemia en Costa Rica.
Abstract The current COVID-19 has spread worldwide, the outbreak is altering the usual activity of the catheterization laboratorios and the usual treatment pathways of patients with chronic diseases or emergencies, such as Acute Coronary Syndrome could be disrupted. The involvement of health personnel is a relevant concern, so we created a consensus document of the Costa Rican Association of Cardiology that aims to generate a decision-making workflow to treat this pathology and guarantee adequate and continuous care for ST elevation myocardial infarction during the COVID-19 outbreak.
Asunto(s)
Protocolos Clínicos , COVID-19/prevención & control , Infarto del Miocardio , Competencia Clínica , Adhesión a Directriz , Costa RicaRESUMEN
La cardiomiopatía inducida por estrés o Síndrome de Takotsubo se caracteriza por una disfunción aguda del ventrículo izquierdo caracterizado por acinesia o discinesia apical con hipercinesia basal a menudo reversible, en ausencia de obstrucción coronaria en la angiografía. La presentación clínica se asemeja al del Infarto Agudo de Miocardio; con un inicio súbito caracterizado por dolor precordial de tipo isquémico, disnea, palpitaciones, cambios electrocardiográficos, elevación de biomarcadores de necrosis miocárdica y en casos más graves y raros shock cardiogénico; el estrés emocional y físico severo suelen ser desencadenantes. Con el presente caso clínico, revisamos las características clínicas, diagnósticas y terapéuticas de ésta entidad poco frecuente que representa cerca del 1% de todos los pacientes con sospecha de síndrome coronario agudo.
Cardiomyopathy induced by stress or Takotsubo Syndrome is characterized by an acute dysfunction of the left ventricle characterized by apical akinesia or dyskinesia with often reversible basal hyperkinesia, in the absence of coronary occlusion on angiography. The clinical presentation resembles the Acute Myocardial Infarction, with a sudden onset characterized by a chest pain angina type, dyspnea, palpitations, electrocardiographic changes, elevation of cardiac biomarkers and cardiogenic shock in more serious and rare cases; the severe emotional and physical stress tend to be triggers. With this clinical case, we reviewed the clinical, diagnostic and therapeutic features of this rare entity which represents about 1% of all patients with suspected acute coronary syndrome.
Asunto(s)
Humanos , Estrés Psicológico , Cardiomiopatía de Takotsubo/diagnóstico , Enfermedades Cardiovasculares/tratamiento farmacológicoRESUMEN
OBJECTIVE: To report the prevalence of metabolic syndrome (MetS) as found by the Central American Diabetes Initiative (CAMDI) study for five major Central American populations: Belize (national); Costa Rica (San José); Guatemala (Guatemala City); Honduras (Tegucigalpa); and Nicaragua (Managua). METHODS: Study data on 6 185 adults aged 20 years or older with anthropometric and laboratory determination of MetS from population-based surveys were analyzed. Overall, the survey response rate was 82.0%. MetS prevalence was determined according to criteria from the Adult Treatment Panel III of the National Cholesterol Education Program. The study's protocol was reviewed and approved by the bioethical committee of each country studied. RESULTS: The overall standardized prevalence of MetS in the Central American region was 30.3% (95% confidence interval (CI): 27.1-33.4). There was wide variability by gender and work conditions, with higher prevalence among females and unpaid workers. The standardized percentage of the population free of any component of MetS was lowest in Costa Rica (9.0%; CI: 6.5-11.4) and highest in Honduras (21.1%; CI: 16.4-25.9). CONCLUSIONS: Overall prevalence of MetS in Central America is high. Strengthening surveillance of chronic diseases and establishing effective programs for preventing cardiovascular diseases might reduce the risk of MetS in Central America.
OBJETIVO: Notificar la prevalencia del síndrome metabólico (SMet) observada en el estudio de la Iniciativa Centroamericana de Diabetes (CAMDI) llevado a cabo en cinco importantes poblaciones centroamericanas: Belice (nacional); Costa Rica (San José); Guatemala (Ciudad de Guatemala); Honduras (Tegucigalpa); y Nicaragua (Managua). MÉTODOS: Se analizaron los datos de estudio obtenidos de las encuestas poblacionales dirigidas a 6 185 adultos de 20 años de edad o mayores con determinaciones antropométricas y de laboratorio relativas al SMet. En términos generales, la tasa de respuesta a las encuestas fue de 82,0%. Se determinó la prevalencia del SMet según los criterios del tercer informe del Grupo de Expertos en el Tratamiento de Adultos (Adult Treatment Panel III) del Programa Nacional de Educación sobre el Colesterol. El protocolo del estudio fue examinado y aprobado por el comité de bioética de cada uno de los países incluidos en el estudio. RESULTADOS: La prevalencia general estandarizada del SMet en Centroamérica fue de 30,3% (Intervalo de confianza de 95% (IC): 27,1-33,4). Se observó una amplia variabilidad según el sexo y las condiciones laborales, con mayor prevalencia en mujeres y trabajadores no retribuidos. El menor porcentaje estandarizado de población libre de cualquier componente del SMet se observó en Costa Rica (9,0%; IC: 6,5-11,4) y el mayor en Honduras (21,1%; IC: 16,4-25,9). CONCLUSIONES: La prevalencia general de SMet en Centroamérica es alta. Se podría reducir el riesgo de SMet en Centroamérica mediante el fortalecimiento de la vigilancia de las enfermedades crónicas y el establecimiento de programas eficaces de prevención de las enfermedades cardiovasculares.
Asunto(s)
Síndrome Metabólico/diagnóstico , Síndrome Metabólico/prevención & control , América CentralRESUMEN
Objective. To report the prevalence of metabolic syndrome (MetS) as found by the Central American Diabetes Initiative (CAMDI) study for five major Central American populations: Belize (national); Costa Rica (San José); Guatemala (Guatemala City); Honduras (Tegucigalpa); and Nicaragua (Managua). Methods. Study data on 6 185 adults aged 20 years or older with anthropometric and laboratory determination of MetS from population-based surveys were analyzed. Overall, the survey response rate was 82.0%. MetS prevalence was determined according to criteria from the Adult Treatment Panel III of the National Cholesterol Education Program. The study’s protocol was reviewed and approved by the bioethical committee of each country studied. Results. The overall standardized prevalence of MetS in the Central American region was 30.3% (95% confidence interval (CI): 27.1–33.4). There was wide variability by gender and work conditions, with higher prevalence among females and unpaid workers. The standardized percentage of the population free of any component of MetS was lowest in Costa Rica (9.0%; CI: 6.5–11.4) and highest in Honduras (21.1%; CI: 16.4–25.9). Conclusions. Overall prevalence of MetS in Central America is high. Strengthening surveillance of chronic diseases and establishing effective programs for preventing cardiovascular diseases might reduce the risk of MetS in Central America.
Objetivo. Notificar la prevalencia del síndrome metabólico (SMet) observada en el estudio de la Iniciativa Centroamericana de Diabetes (CAMDI) llevado a cabo en cinco importantes poblaciones centroamericanas: Belice (nacional); Costa Rica (San José); Guatemala (Ciudad de Guatemala); Honduras (Tegucigalpa); y Nicaragua (Managua). Métodos. Se analizaron los datos de estudio obtenidos de las encuestas poblacionales dirigidas a 6 185 adultos de 20 años de edad o mayores con determinaciones antropométricas y de laboratorio relativas al SMet. En términos generales, la tasa de respuesta a las encuestas fue de 82,0%. Se determinó la prevalencia del SMet según los criterios del tercer informe del Grupo de Expertos en el Tratamiento de Adultos (Adult Treatment Panel III) del Programa Nacional de Educación sobre el Colesterol. El protocolo del estudio fue examinado y aprobado por el comité de bioética de cada uno de los países incluidos en el estudio. Resultados. La prevalencia general estandarizada del SMet en Centroamérica fue de 30,3% (Intervalo de confianza de 95% (IC): 27,1–33,4). Se observó una amplia variabilidad según el sexo y las condiciones laborales, con mayor prevalencia en mujeres y trabajadores no retribuidos. El menor porcentaje estandarizado de población libre de cualquier componente del SMet se observó en Costa Rica (9,0%; IC: 6,5–11,4) y el mayor en Honduras (21,1%; IC: 16,4–25,9). Conclusiones. La prevalencia general de SMet en Centroamérica es alta. Se podría reducir el riesgo de SMet en Centroamérica mediante el fortalecimiento de la vigilancia de las enfermedades crónicas y el establecimiento de programas eficaces de prevención de las enfermedades cardiovasculares.
Asunto(s)
Síndrome Metabólico , Belice , Costa Rica , Guatemala , Honduras , Nicaragua , América Central , Síndrome Metabólico , Belice , América CentralRESUMEN
OBJECTIVE: To report the prevalence of metabolic syndrome (MetS) as found by the Central American Diabetes Initiative (CAMDI) study for five major Central American populations: Belize (national); Costa Rica (San José); Guatemala (Guatemala City); Honduras (Tegucigalpa); and Nicaragua (Managua). METHODS: Study data on 6 185 adults aged 20 years or older with anthropometric and laboratory determination of MetS from population-based surveys were analyzed. Overall, the survey response rate was 82.0%. MetS prevalence was determined according to criteria from the Adult Treatment Panel III of the National Cholesterol Education Program. The study's protocol was reviewed and approved by the bioethical committee of each country studied. RESULTS: The overall standardized prevalence of MetS in the Central American region was 30.3% (95% confidence interval (CI): 27.1-33.4). There was wide variability by gender and work conditions, with higher prevalence among females and unpaid workers. The standardized percentage of the population free of any component of MetS was lowest in Costa Rica (9.0%; CI: 6.5-11.4) and highest in Honduras (21.1%; CI: 16.4-25.9). CONCLUSIONS: Overall prevalence of MetS in Central America is high. Strengthening surveillance of chronic diseases and establishing effective programs for preventing cardiovascular diseases might reduce the risk of MetS in Central America.
Asunto(s)
Síndrome Metabólico/epidemiología , Adulto , Anciano , América Central/epidemiología , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Adulto JovenRESUMEN
La coronariopatía arterio esclerótica continúa siendo la principal causa de mortalidad mundial y Costa Rica no escapa a esta realidad. La prueba de esfuerzo, la imagen de perfusión con SESTAMIBI y la angiografía coronaria son métodos que permiten detectar esta entidad. El país no cuenta con datos sobre la información que proporcionan estas pruebas. El objetivo del estudio es determinar la rentabilidad diagnóstica de cada una de ellas. Métodos: Es un estudio observacional, analítico de cohorte. Se incluyeron pacientes con factores de riesgo cardiovascular, que tuvieran prueba de esfuerzo, estudio de perfusión miocárdica y angiografía coronaria realizadas en el Hospital San Juan de Dios, desde 2003 a 2007. Se calculó la sensibilidad y especificidad de estos estudios. También se llevó a cabo un análisis con una estadística descriptiva de las características de la muestra y de los diferentes factores de riesgo cardiovascular. Resultados: Se incluyeron 83 pacientes en el estudio, 75 por ciento hombres. Los principales factores de riesgo encontrados fueron dislipidemia, 84 por ciento, e hipertensión arterial, 70 por ciento. La prueba de esfuerzo tuvo una sensibilidad del 40 por ciento y una especificidad del 57 por ciento; el estudio de perfusión miocárdica con SESTAMIBI tuvo una sensibilidad del 66 por ciento y una especificidad del 71 por ciento. La mayoría de los pacientes tuvieron afección de uno o dos vasos coronarios, con lesiones mayores al 90 por ciento, y especialmente en la arteria descendente anterior. Conclusión: Los factores de riesgo convencionales se presentaron en un alto porcentaje de la población estudiada. La prueba de esfuerzo mostró una baja sensibilidad y especificidad, sin embargo, coincide con el rango descrito en la literatura. El estudio de perfusión miocárdica con SESTAMIBI mostró un rendimiento diagnóstico significativamente superior (p=0.05).
Coronary artery disease is the first cause of mortality around the world, and Costa Rica does not escape from this reality. The treadmill test, myocardial perfusion imaging withSESTAMIBI, and coronary angiography are methods for detecting this disease. Our country does not have its own data regarding these tests. The aim of this study is to determine the diagnostic performance of each one. Methods: The present is an observational, analytic, cohort study. Patients included were those with cardiovascular risk factors that underwent a treadmill test, myocardial perfusion imaging, and a coronary angiography at the Hospital San Juan de Dios, from 2003 to 2007. Sensitivity and specificity were calculated. A descriptive statistic analysis of the different risk factors was carried out. Results: Eighty three patients were included in the study; 75% men and 25% women. The mostfrequently found risk factors were dyslipidemia (84%), and hypertension (70%). The treadmill test had a sensitivity of 40%, and specificity of 57%. Myocardial perfusion imaging withSESTAMIBI had a sensitivity of 66% and specificity of 71%. The majority of the patients had lesions in 1 or 2 coronary arteries, with more than 90% obstruction, mostly in the anterior arterydescending. Conclusion: A high prevalence of conventional risk factors was present in this population. Thetreadmill test showed a low sensitivity and specificity, according with the literature. The myocardial perfusion imaging had a significant (p =0.05) better diagnostic performance than thetreadmill test.
Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Cardiología , Angiografía Coronaria , Enfermedad Coronaria/diagnóstico , Prueba de Esfuerzo , Reperfusión Miocárdica , Perfusión , Costa RicaRESUMEN
This work shows the results of four Electro-Fenton laboratory tests to reduce the chemical oxygen demand (COD) in spent caustic solutions. The treatment consisted of (i) a pH reduction followed by (ii) an Electro-Fenton process, which was analyzed in this work. The Fenton's reagent was produced in a specially designed reactor, where the waste stream flowed through a labyrinth made by ferrous plates. These plates acted as sacrificial anodes-releasing Fe(2 +) cations to the solution, where H(2)O(2) was also added. The Electro-Fenton process was analyzed varying the ferrous ion concentration ([Fe(+ 2)]), the spent caustic's initial temperature and the initial pH. Close to 95% removal of COD (from 8800 mg L(- 1)) was achieved at a pH of 4, a temperature of 40 degrees C and 100 mg L(- 1) of Fe(+ 2) (applying 1 A). Two models were considered to simulate the behavior of the reactor considering (i) axial dispersion and (ii) kinetic rate, respectively. The model that was based on kinetics, proved to be the slightly closest fit to the experimental values.
Asunto(s)
Reactores Biológicos , Electroquímica/métodos , Peróxido de Hidrógeno/química , Hierro/química , Modelos Teóricos , Oxidación-ReducciónRESUMEN
Medium spiny projection neurons (MSNs) are the main neuronal population in the neostriatum. MSNs are inhibitory and GABAergic. MSNs connect with other MSNs via local axon collaterals that produce lateral inhibition, which is thought to select cell assemblies for motor action. MSNs also receive inhibitory inputs from GABAergic local interneurons. This work shows, through the use of the paired pulse protocol, that somatostatin (SST) acts presynaptically to regulate GABA release from the terminals interconnecting MSNs. This SST action is reversible and not mediated through the release of dopamine. It is blocked by the SST receptor (SSTR) antagonist ciclosomatostatin (cicloSST). In contrast, SST does not regulate inhibition coming from interneurons. Because, SST is released by a class of local interneuron, it is concluded that this neuron helps to regulate the selection of motor acts.
Asunto(s)
Cuerpo Estriado/metabolismo , Potenciales Postsinápticos Inhibidores/fisiología , Neuronas/metabolismo , Terminales Presinápticos/metabolismo , Somatostatina/metabolismo , 6-Ciano 7-nitroquinoxalina 2,3-diona/metabolismo , Potenciales de Acción/fisiología , Animales , Cuerpo Estriado/citología , Agonistas de Aminoácidos Excitadores/metabolismo , Antagonistas de Aminoácidos Excitadores/metabolismo , N-Metilaspartato/metabolismo , Neuronas/citología , Técnicas de Placa-Clamp , Ratas , Ratas Wistar , Valina/análogos & derivados , Valina/metabolismo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiónico/metabolismoRESUMEN
This work investigated if diverse properties could be ascribed to evoked inhibitory postsynaptic currents (IPSCs) recorded on rat neostriatal neurons when field stimulation was delivered at two different locations: the globus pallidus (GP) and the neostriatum (NS). Previous work stated that stimulation in the GP could antidromically excite projection axons from medium spiny neurons. This maneuver would predominantly activate the inhibitory synapses that interconnect spiny cells. In contrast, intrastriatal stimulation would preferentially activate inhibitory synapses provided by interneurons. This study shows that, in fact, intensity-amplitude experiments are able to reveal different properties for IPSCs evoked from these two locations (GP and NS). In addition, while all IPSCs evoked from the GP were always sensitive to omega-conotoxin GVIA (Ca(V2.2)2.2 or N-channel blocker), one-half of the inhibition evoked from the NS exhibited little sensitivity to omega-conotoxin GVIA. Characteristically, all omega-conotoxin GVIA-insensitive IPSCs exhibited strong paired pulse depression, whereas omega-conotoxin GVIA-sensitive IPSCs evoked from either the GP or the NS could exhibit short-time depression or facilitation. omega-Agatoxin TK (Ca(V2.1)2.1+ or P/Q-channel blocker) blocked IPSCs evoked from both locations. Therefore 1) distinct inhibitory inputs onto projection neostriatal cells can be differentially stimulated with field electrodes; 2) N-type Ca2+ channels are not equally expressed in inhibitory terminals activated in the NS; and 3) synapses that interconnect spiny neurons use both N- and P/Q-type Ca2+ channels.
Asunto(s)
Neostriado/fisiología , Inhibición Neural/fisiología , Neuronas/fisiología , Transmisión Sináptica/fisiología , Animales , Estimulación Eléctrica/métodos , Femenino , Técnicas In Vitro , Masculino , Vías Nerviosas/fisiología , Ratas , Ratas WistarRESUMEN
Besides a reduction of L-type Ca2+-currents (Ca(V)1), muscarine and the peptidic M1-selective agonist, MT-1, reduced currents through Ca(V)2.1 (P/Q) and Ca(V)2.2 (N) Ca2+ channel types. This modulation was strongly blocked by the peptide MT-7, a specific muscarinic M1-type receptor antagonist but not significantly reduced by the peptide MT-3, a specific muscarinic M4-type receptor antagonist. Accordingly, MT-7, but not MT-3, blocked a muscarinic reduction of the afterhyperpolarizing potential (AHP) and decreased the GABAergic inhibitory postsynaptic currents (IPSCs) produced by axon collaterals that interconnect spiny neurons. Both these functions are known to be dependent on P/Q and N types Ca2+ channels. The action on the AHP had an important effect in increasing firing frequency. The action on the IPSCs was shown to be caused presynaptically as it coursed with an increase in the paired-pulse ratio. These results show: first, that muscarinic M1-type receptor activation is the main cholinergic mechanism that modulates Ca2+ entry through voltage-dependent Ca2+ channels in spiny neurons. Second, this muscarinic modulation produces a postsynaptic facilitation of discharge together with a presynaptic inhibition of the GABAergic control mediated by axon collaterals. Together, both effects would tend to recruit more spiny neurons for the same task.
Asunto(s)
Acetilcolina/metabolismo , Caveolinas/fisiología , Neostriado/citología , Neuronas/fisiología , Transmisión Sináptica/fisiología , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Animales , Bloqueadores de los Canales de Calcio/farmacología , Caveolina 2 , Caveolinas/clasificación , Caveolinas/efectos de los fármacos , Células Cultivadas , Interacciones Farmacológicas , Estimulación Eléctrica/métodos , Técnicas In Vitro , Masculino , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Potenciales de la Membrana/efectos de la radiación , Muscarina/farmacología , Agonistas Muscarínicos/clasificación , Agonistas Muscarínicos/farmacología , Inhibición Neural/efectos de los fármacos , Inhibición Neural/fisiología , Neuronas/efectos de los fármacos , Técnicas de Placa-Clamp/métodos , Ratas , Ratas Wistar , Receptores Muscarínicos/clasificación , Receptores Muscarínicos/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacosRESUMEN
Dopamine is a critical modulator of striatal function; its absence produces Parkinson's disease. Most cellular actions of dopamine are still unknown. This work describes the presynaptic actions of dopaminergic receptor agonists on GABAergic transmission between neostriatal projection neurons. Axon collaterals interconnect projection neurons, the main axons of which project to other basal ganglia nuclei. Most if not all of these projecting axons pass through the globus pallidus. Thus, we lesioned the intrinsic neurons of the globus pallidus and stimulated neostriatal efferent axons antidromically with a bipolar electrode located in this nucleus. This maneuver revealed a bicuculline-sensitive synaptic current while recording in spiny cells. D1 receptor agonists facilitated whereas D2 receptor agonists depressed this synaptic current. In contrast, a bicuculline-sensitive synaptic current evoked by field stimulation inside the neostriatum was not consistently modulated, in agreement with previous studies. The data are discussed in light of the most recent experimental and modeling results. The conclusion was that inhibition of spiny cells by axon collaterals of other spiny cells is quantitatively important; however, to be functionally important, this inhibition might be conditioned to the synchronized firing of spiny neurons. Finally, dopamine exerts a potentially important role regulating the extent of lateral inhibition.
Asunto(s)
Axones/fisiología , Cuerpo Estriado/fisiología , Dopamina/metabolismo , Neuronas/fisiología , Animales , Axones/efectos de los fármacos , Cuerpo Estriado/citología , Cuerpo Estriado/efectos de los fármacos , Agonistas de Dopamina/farmacología , Estimulación Eléctrica , Antagonistas del GABA/farmacología , Globo Pálido/citología , Globo Pálido/efectos de los fármacos , Globo Pálido/fisiología , Técnicas In Vitro , Neostriado/citología , Neostriado/efectos de los fármacos , Neostriado/fisiología , Neuronas/efectos de los fármacos , Neuronas/ultraestructura , Técnicas de Placa-Clamp , Ratas , Ratas Wistar , Receptores Dopaminérgicos/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Transmisión Sináptica/fisiología , Ácido gamma-Aminobutírico/metabolismoRESUMEN
El trabajo de investigación realizado en los cuatro municipios estudiados, ofrece una visión panorámica sobre las principales limitaciones que enfrentan éstos para invertir los recursos HIPC II (Highly Indebted Poor Countries/Paises Pobres Altamente Endeudados) en la implementación de políticas sociales.
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Cambio Social , Ciudades , Política PúblicaRESUMEN
El presente estudio se realizó con el propósito de conocer la realidad del negocio lechero, determinar el flujo económico que gira en torno a este rubro y proponer estrategias que impulsen el desarrollo de este sector para este estudio se utilizó la metodología del PADER -COSUDE y el Diseño estadístico propuesto por Fisher denominado "Muestra de poblaciones Finitas e Infinitas". Se determinó que la zona en estudio involucra a 353 familias, con una producción promedio de 10.5 litros vaca/día dichos rendimientos podrían ser incrementados con un mejor manejo, nutrición y una visión del productor hacia una lechería especializada que impulse el desarrollo socioeconómico de las familias del área rural del municipio de San Benito. Este sector invierte más de 230 mil $Us/año en la producción de leche de los cuales 55.720 mil $Us/año son destinados a la compra de bienes y servicios, en función a estos datos es necesario que las instituciones públicas y privadas reorienten sus inversiones. Se puede mejorar la competitividad de esta cadena siempre y cuando los actores sociales; los ambientes organizacional e institucional implementen políticas de apoyo y fomento.