Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Rev Epidemiol Sante Publique ; 68(4): 215-225, 2020 Aug.
Artículo en Francés | MEDLINE | ID: mdl-32653261

RESUMEN

BACKGROUND: The screening of patients who are at-risk drinkers, which means exceeding the thresholds defined by health authorities or associated with a specific situation (taking psychotropic drugs, having an organic pathology, driving a vehicle, drinking during pregnancy), represents a major issue in primary care. Few studies have offered perspective from the patients' standpoint. The main purpose of this study was to describe general practitioners at-risk drinking screening from their patients point of view. The secondary objective was to identify the factors associated with perception of satisfactory general practitioner knowledge about alcohol consumption. METHODS: A quantitative cross-sectional study was launched in 9 general practitioner offices over 6 months. Patients older than 18 were recruited to answer a questionnaire blinded from their general practitioner, indicating the level of their alcohol consumption and their perception regarding their general practitioner's screening methods. Descriptive, univariate and multivariate logistic regression analyses were performed. RESULTS: All in all, 445 patients were analyzed. Sixty-two at-risk drinkers were screened (13.9 %). Most of the patients declared they had not been interviewed about their alcohol consumption by their general practitioner either during initial consultations (86.1 %) or over time (83.3 %). Only 4.2 % of patients had previously initiated discussion about their consumption. Patients were not ashamed to talk about alcohol (99.2 %) and found their general practitioner to be competent on this topic (100 %). In multivariate analysis, independent factors associated with a good general practitioner knowledge about their patients' current consumption were the questions put forward by their general practitioner about alcohol consumption during their first visit (P<0.001) and during subsequent visits (P<0.001). CONCLUSION: This study showed a low general practitioner screening rate of their patients' at-risk drinking. Only a minority of patients, including at-risk drinkers, declared that their general practitioner was aware of their level of alcohol consumption. Screening could be improved by being systematized during initial consultations and regularly scheduled during subsequent visits, especially in at-risk situations.


Asunto(s)
Consumo de Bebidas Alcohólicas , Alcoholismo/diagnóstico , Médicos Generales , Tamizaje Masivo , Adulto , Anciano , Consumo de Bebidas Alcohólicas/epidemiología , Alcoholismo/epidemiología , Alcoholismo/etiología , Alcoholismo/prevención & control , Estudios Transversales , Diagnóstico Precoz , Femenino , Médicos Generales/estadística & datos numéricos , Conductas de Riesgo para la Salud , Humanos , Masculino , Tamizaje Masivo/métodos , Tamizaje Masivo/normas , Tamizaje Masivo/estadística & datos numéricos , Persona de Mediana Edad , Pautas de la Práctica en Medicina/estadística & datos numéricos , Atención Primaria de Salud/métodos , Atención Primaria de Salud/normas , Atención Primaria de Salud/estadística & datos numéricos , Factores de Riesgo , Encuestas y Cuestionarios
2.
Molecules ; 24(9)2019 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-31058815

RESUMEN

c-Jun N-terminal kinase (JNK) is activated by various brain insults and is implicated in neuronal injury triggered by reperfusion-induced oxidative stress. Some JNK inhibitors demonstrated neuroprotective potential in various models, including cerebral ischemia/reperfusion injury. The objective of the present work was to study the neuroprotective activity of a new specific JNK inhibitor, IQ-1S (11H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt), in the model of global cerebral ischemia (GCI) in rats compared with citicoline (cytidine-5'-diphosphocholine), a drug approved for the treatment of acute ischemic stroke and to search for pleiotropic mechanisms of neuroprotective effects of IQ-1S. The experiments were performed in a rat model of ischemic stroke with three-vessel occlusion (model of 3VO) affecting the brachiocephalic artery, the left subclavian artery, and the left common carotid artery. After 7-min episode of GCI in rats, 25% of animals died, whereas survived animals had severe neurological deficit at days 1, 3, and 5 after GCI. At day 5 after GCI, we observing massive loss of pyramidal neurons in the hippocampal CA1 area, increase in lipid peroxidation products in the brain tissue, and decrease in local cerebral blood flow (LCBF) in the parietal cortex. Moreover, blood hyperviscosity syndrome and endothelial dysfunction were found after GCI. Administration of IQ-1S (intragastrically at a dose 50 mg/kg daily for 5 days) was associated with neuroprotective effect comparable with the effect of citicoline (intraperitoneal at a dose of 500 mg/kg, daily for 5 days).The neuroprotective effect was accompanied by a decrease in the number of animals with severe neurological deficit, an increase in the number of animals with moderate degree of neurological deficit compared with control GCI group, and an increase in the number of unaltered neurons in the hippocampal CA1 area along with a significant decrease in the number of neurons with irreversible morphological damage. In rats with IQ-1S administration, the LCBF was significantly higher (by 60%) compared with that in the GCI control. Treatment with IQ-1S also decreases blood viscosity and endothelial dysfunction. A concentration-dependent decrease (IC50 = 0.8 ± 0.3 µM) of tone in isolated carotid arterial rings constricted with phenylephrine was observed after IQ-1S application in vitro. We also found that IQ-1S decreased the intensity of the lipid peroxidation in the brain tissue in rats with GCI. 2.2-Diphenyl-1-picrylhydrazyl scavenging for IQ-1S in acetonitrile and acetone exceeded the corresponding values for ionol, a known antioxidant. Overall, these results suggest that the neuroprotective properties of IQ-1S may be mediated by improvement of cerebral microcirculation due to the enhanced vasorelaxation, beneficial effects on blood viscosity, attenuation of the endothelial dysfunction, and antioxidant/antiradical IQ-1S activity.


Asunto(s)
Isquemia Encefálica/prevención & control , Citidina Difosfato Colina/administración & dosificación , Fármacos Neuroprotectores/administración & dosificación , Oximas/administración & dosificación , Quinoxalinas/administración & dosificación , Daño por Reperfusión/prevención & control , Animales , Isquemia Encefálica/metabolismo , Circulación Cerebrovascular , Citidina Difosfato Colina/farmacología , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Humanos , Peroxidación de Lípido/efectos de los fármacos , Masculino , Fármacos Neuroprotectores/farmacología , Oximas/farmacología , Quinoxalinas/farmacología , Ratas , Ratas Wistar , Resultado del Tratamiento
3.
J Thorac Cardiovasc Surg ; 163(4): 1393-1403.e9, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-32718702

RESUMEN

OBJECTIVE: Acute kidney injury (AKI) is a serious complication of cardiac surgery with cardiopulmonary bypass (CPB). The aim of this study was to evaluate the effects of nitric oxide (NO) supplementation to the CPB circuit on the development of cardiac surgery-associated AKI. METHODS: This prospective randomized controlled study included 96 patients with moderate risk of renal complications who underwent elective cardiac surgery with CPB. The study protocol was registered at ClinicalTrials.gov (identifier NCT03527381). Patients were randomly allocated to either NO supplementation to the CPB bypass circuit (NO treatment group; n = 48) or usual care (control group; n = 48). In the NO treatment group, 40-ppm NO was administered during the entire CPB period. The primary outcome was the incidence of AKI. RESULTS: NO treatment was associated with a significant decrease in AKI incidence (10 cases [20.8%] vs 20 cases [41.6%] in the control group; relative risk, 0.5; 95% confidence interval, 0.26-0.95; P = .023) and a higher median urine output during CPB (2.6 mL/kg/h [interquartile range (IQR), 2.1-5.08 mL/kg/h] vs 1.7 mL/kg/h [IQR, 0.80-2.50 mL/kg/h]; P = .0002). The median urinary neutrophil gelatinase-associated lipocalin level at 4 hours after surgery was significantly lower in the NO treatment group (1.12 ng/mL [IQR, 0.75-5.8 ng/mL] vs 4.62 ng/mL [IQR, 2.02-34.55 ng/mL]; P = .005). In the NO treatment group, concentrations of NO metabolites were significantly increased at 5 minutes postclamping, at 5 minutes after declamping, and at the end of the operation. Concentrations of proinflammatory and anti-inflammatory mediators and free plasma hemoglobin did not differ significantly between the 2 groups. CONCLUSIONS: NO administration in patients at moderate risk of renal complications undergoing elective cardiac surgery with CPB was associated with a lower incidence of AKI.


Asunto(s)
Lesión Renal Aguda/prevención & control , Puente Cardiopulmonar , Óxido Nítrico/administración & dosificación , Complicaciones Posoperatorias/prevención & control , Anciano , Femenino , Hemoglobinas/análisis , Humanos , Lipocalina 2/orina , Masculino , Persona de Mediana Edad , Nitratos/sangre , Dióxido de Nitrógeno/sangre , Estudios Prospectivos
4.
Trop Med Int Health ; 15(11): 1274-7, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20976874

RESUMEN

Is a published research paper an important indicator of successful operational research at programme level in low-income countries? In academia, publishing in peer-reviewed scientific journals is highly encouraged and strongly pursued for academic recognition and career progression. In contrast, for those who engage in operational research at programme level, there is often no necessity or reward for publishing the results of research studies; it may even be criticized as being an unnecessary detraction from programme-related work. We present arguments to support publishing operational research from low-income countries; we highlight some of the main reasons for failure of publication at programme level and suggest ways forward.


Asunto(s)
Países en Desarrollo , Investigación Operativa , Publicaciones Periódicas como Asunto , Edición , Humanos , Indicadores de Calidad de la Atención de Salud
5.
Cells ; 9(8)2020 08 08.
Artículo en Inglés | MEDLINE | ID: mdl-32784475

RESUMEN

A novel specific inhibitor of c-Jun N-terminal kinase, 11H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt (IQ-1S), has a high affinity to JNK3 compared to JNK1/JNK2. The aim of this work was to study the mechanisms of neuroprotective activity of IQ-1S in the models of reversible focal cerebral ischemia (FCI) in Wistar rats. The animals were administered with an intraperitoneal injection of IQ-1S (5 and 25 mg/kg) or citicoline (500 mg/kg). Administration of IQ-1S exerted a pronounced dose-dependent neuroprotective effect, not inferior to the effects of citicoline. Administration of IQ-1S at doses of 5 and 25 mg/kg reduced the infarct size by 20% and 50%, respectively, 48 h after FCI, whereas administration of citicoline reduced the infarct size by 34%. The administration of IQ-1S was associated with a faster amelioration of neurological status. Control rats showed a 2.0-fold increase in phospho-c-Jun levels in the hippocampus compared to the corresponding values in sham-operated rats 4 h after FCI. Administration of IQ-1S at a dose of 25 mg/kg reduced JNK-dependent phosphorylation of c-Jun by 20%. Our findings suggest that IQ-1S inhibits JNK enzymatic activity in the hippocampus and protects against stroke injury when administered in the therapeutic and prophylactic regimen in the rat model of FCI.


Asunto(s)
Isquemia Encefálica/tratamiento farmacológico , Hipocampo/efectos de los fármacos , Proteínas Quinasas JNK Activadas por Mitógenos/antagonistas & inhibidores , Fármacos Neuroprotectores , Oximas , Inhibidores de Proteínas Quinasas , Quinoxalinas , Daño por Reperfusión/tratamiento farmacológico , Animales , Modelos Animales de Enfermedad , Hipocampo/patología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Masculino , Fármacos Neuroprotectores/administración & dosificación , Fármacos Neuroprotectores/farmacología , Oximas/administración & dosificación , Oximas/farmacología , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Proteínas Quinasas/farmacología , Quinoxalinas/administración & dosificación , Quinoxalinas/farmacología , Ratas , Ratas Wistar
6.
Hypertens Res ; 43(10): 1068-1078, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32382155

RESUMEN

c-Jun N-terminal kinases (JNKs) are involved in the myocardial and aortic remodeling, increased arterial tone, and arterial blood pressure elevation associated with hypertension. The aim of the present study was to investigate the antihypertensive effect of a new JNK inhibitor, 1H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt (IQ-1S), on spontaneously hypertensive rats (SHRs). Experiments were performed using normotensive Wistar-Kyoto (WKY) rats and SHRs. Experimental groups of SHRs received IQ-1S intragastrically for 6 weeks in daily doses of 5 and 50 mg/kg; experimental groups of WKY rats received 50 mg/kg IQ-1S according to the same regimen. The IQ-1S administration regimen induced decreases in systolic blood pressure, mean arterial blood pressure, total peripheral resistance, blood viscosity, hematocrit, myocardial cell cross-sectional area, and aortic wall thickness in SHRs vs untreated SHRs. There were no significant differences in systolic blood pressure values between the control and experimental groups of WKY rats during the treatment period. A concentration-dependent decrease in the tone of carotid arterial rings isolated from SHRs was observed after JNK inhibitor application in vitro. Application of the JNK inhibitor diminished endothelin-1 secretion by human umbilical vein endothelial cells in vitro. The main mechanisms of the antihypertensive effect of IQ-1S included the attenuation of blood viscosity due to decreased hematocrit, a vasodilatory effect on arterial smooth muscle cells, and a decrease in endothelin-1 production by endothelial cells.


Asunto(s)
Hipertensión/tratamiento farmacológico , Proteínas Quinasas JNK Activadas por Mitógenos/antagonistas & inhibidores , Oximas/uso terapéutico , Quinoxalinas/uso terapéutico , Animales , Aorta Torácica/efectos de los fármacos , Viscosidad Sanguínea/efectos de los fármacos , Evaluación Preclínica de Medicamentos , Corazón/efectos de los fármacos , Hematócrito , Hemodinámica/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana , Humanos , Masculino , Oximas/farmacología , Quinoxalinas/farmacología , Ratas Endogámicas SHR , Ratas Endogámicas WKY
7.
J Thorac Cardiovasc Surg ; 157(6): 2328-2336.e1, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30447958

RESUMEN

OBJECTIVES: The aim of this pilot study was to elucidate the effects of exogenous nitric oxide (NO) supply to the extracorporeal circulation circuit for cardioprotection against ischemia-reperfusion injury during coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). METHODS: A total of 60 patients with coronary artery disease scheduled for CABG with CPB were enrolled in a prospective randomized study. Patients were allocated randomly to receive treatment according to standard or modified CPB protocol where 40-ppm NO was added to the CPB circuit during cardiac surgery. The primary endpoint was the measurement of cardiac troponin I (cTnI). The secondary end points consisted in the measurements of creatine kinase-muscle/brain fraction (CK-MB) and vasoactive inotropic score (VIS). RESULTS: NO delivered into the CPB circuit had a cardioprotective effect. The level of cTnI was significantly lower in NO-treated group compared with the control group 6 hours after surgery: 1.79 ± 0.39 ng/mL versus 2.41 ± 0.55 ng/mL, respectively (P = .001). The CK-MB value was significantly lower in NO-treated group compared with the control group 24 hours after surgery: 47.69 ± 8.08 U/L versus 62.25 ± 9.78 U/L, respectively (P = .001); and the VIS was significantly lower in the NO-treated group 6 hours after the intervention. CONCLUSIONS: NO supply to the CPB circuit during CABG exerted a cardioprotective effect and was associated with lower levels of VIS and cardiospecific blood markers cTnI and CK-MB.


Asunto(s)
Puente Cardiopulmonar/métodos , Cardiotónicos/uso terapéutico , Puente de Arteria Coronaria/métodos , Óxido Nítrico/uso terapéutico , Biomarcadores/sangre , Puente de Arteria Coronaria/efectos adversos , Enfermedad de la Arteria Coronaria/cirugía , Forma MB de la Creatina-Quinasa/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Daño por Reperfusión Miocárdica/prevención & control
8.
Food Res Int ; 108: 551-557, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29735090

RESUMEN

The aim of the present study was to add microencapsulated Jabuticaba aqueous extract (MJE) to mortadella as a natural dye and to evaluate its possible antioxidant and antimicrobial activity during refrigeration. Anthocyanins in the extract were quantified and identified. Three treatments of mortadella were prepared: without dye (Control), with cochineal carmine (Carmine) and with the addition of 2% MJE. We determined the chemical composition of mortadella, along with pH, instrumental color, lipid oxidation, microbiological characteristics (Escherichia coli, Staphylococcus aureus, Salmonella, sulphite-reducing Clostridium, aerobic mesophiles, aerobic psychrotrophics and lactic acid bacteria) and sensory acceptance during storage at 4 °C for 56 days. MJE showed high content of anthocyanins, with prevalence of cyanidin-3-glucoside. MJE improved sensory acceptance of texture and flavor of mortadella (P < 0.05), but we observed a slight decrease in color and aroma attributes (P < 0.05). Lipid oxidation of mortadella was not influenced by MJE or cochineal carmine. MJE also displayed a minor effect on physicochemical and microbiological characteristics during storage. As MJE did not alter most of mortadella sausage's evaluated characteristics, it could be used as a natural dye in order to make better use of agro industry waste and to create a meat product enriched with natural antioxidants.


Asunto(s)
Colorantes/química , Conservación de Alimentos/métodos , Conservantes de Alimentos/química , Almacenamiento de Alimentos/métodos , Productos de la Carne/análisis , Myrtaceae/química , Extractos Vegetales/química , Carne Roja/análisis , Animales , Antiinfecciosos/química , Antiinfecciosos/aislamiento & purificación , Antioxidantes/química , Antioxidantes/aislamiento & purificación , Carmín/química , Color , Colorantes/aislamiento & purificación , Comportamiento del Consumidor , Microbiología de Alimentos/métodos , Conservantes de Alimentos/aislamiento & purificación , Humanos , Productos de la Carne/microbiología , Percepción Olfatoria , Oxidación-Reducción , Extractos Vegetales/aislamiento & purificación , Carne Roja/microbiología , Olfato , Sus scrofa , Gusto , Percepción del Gusto , Factores de Tiempo
9.
J Child Neurol ; 22(9): 1084-9, 2007 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-17890405

RESUMEN

We studied the relationships between magnetic resonance imaging (MRI) findings and neuropsychological sequelae in children after severe traumatic brain injury. Twenty-three children ages 7-13 years underwent MRI assessment of brain lesion topography and volume and neuropsychological evaluations, more than 1 year after sustaining severe traumatic brain injury. Most children had lesions to the corpus callosum and frontal lobes. Total lesion volume and extent of cerebral atrophy did not impact on the neuropsychological evaluation. Additional relationships were observed: left frontal lesions with lower semantic verbal fluency, right occipital lesions with lower visual recognition task scores, dyscalculia with cerebellar lesions, and cerebellar damage with lower cognitive performances and lower visual recognition memory. This study demonstrates the significance of the cerebellum's role in neuropsychological outcomes after traumatic brain injury and the importance of the lesion depth classification in predicting functional results.


Asunto(s)
Lesiones Encefálicas/patología , Lesiones Encefálicas/psicología , Enfermedades Cerebelosas/patología , Enfermedades Cerebelosas/psicología , Cerebelo/lesiones , Cerebelo/patología , Adolescente , Factores de Edad , Lesiones Encefálicas/fisiopatología , Enfermedades Cerebelosas/etiología , Cerebelo/fisiopatología , Niño , Trastornos del Conocimiento/etiología , Trastornos del Conocimiento/patología , Trastornos del Conocimiento/fisiopatología , Cuerpo Calloso/lesiones , Cuerpo Calloso/patología , Cuerpo Calloso/fisiopatología , Evaluación de la Discapacidad , Femenino , Lóbulo Frontal/lesiones , Lóbulo Frontal/patología , Lóbulo Frontal/fisiopatología , Humanos , Imagen por Resonancia Magnética , Masculino , Trastornos de la Memoria/etiología , Trastornos de la Memoria/patología , Trastornos de la Memoria/fisiopatología , Pruebas Neuropsicológicas , Lóbulo Occipital/lesiones , Lóbulo Occipital/patología , Lóbulo Occipital/fisiopatología , Reconocimiento Visual de Modelos/fisiología , Pronóstico , Trastornos del Habla/etiología , Trastornos del Habla/patología , Trastornos del Habla/fisiopatología , Trastornos de la Visión/etiología , Trastornos de la Visión/patología , Trastornos de la Visión/fisiopatología
14.
Cell Physiol Biochem ; 21(1-3): 29-36, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18209469

RESUMEN

Previously, we reported that hyposmotic swelling evoked transient vascular smooth muscle cell (SMC) contraction that was completely abolished by L-type Ca(2+) channel blockers. In contrast, sustained contraction revealed in hyper- and isoosmotically-shrunken SMCs was insensitive to L-type channel blockers and was diminished in Ca(2+)-free medium by only 30-50%. Several research groups reported cell volume-dependent cytoskeleton network rearrangements. This study examines the role of cytoskeleton proteins in cell volume-dependent contraction of endothelium-denuded vascular smooth muscle rings (VSMR) from the rat thoracic aorta. Hyperosmotic shrinkage and hyposmotic swelling were triggered by modulation of medium osmolality; isosmotic shrinkage was induced by VSMR transfer from hypo- to isosmotic medium. The relative content of globular (G) and fibrillar (F) actin was estimated by fluorescence microscopy. Hyperosmotic shrinkage and hyposmotic swelling led to elevation of the F-actin/G-actin ratio by 2.5- and 1.8-fold respectively. Contraction of shrunken and swollen VSMR was insensitive to modulators of microtubules such as vinblastine, colchicine and docetaxel. Microfilament disassembly by cytochalasin B resulted in dramatic attenuation of the maximal amplitude of contraction of hyperosmotically-shrunken and hyposmotically-swollen VSMR, and almost completely abolished the contraction triggered by isosmotic shrinkage. These data suggest that both L-type Ca(2+) channel-mediated contraction of swollen vascular SMC and Ca(2+)(o)-insensitive contractions of shrunken cells are triggered by reorganization of the microfilament network caused by elevation of the F-actin/G-actin ratio.


Asunto(s)
Tamaño de la Célula , Citoesqueleto/metabolismo , Contracción Muscular , Músculo Liso Vascular/citología , Actinas/metabolismo , Animales , Tamaño de la Célula/efectos de los fármacos , Citocalasina B/farmacología , Citoesqueleto/efectos de los fármacos , Contracción Isométrica/efectos de los fármacos , Contracción Muscular/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Concentración Osmolar , Ratas , Ratas Wistar , Vinblastina/farmacología
15.
Artif Organs ; 22(6): 461-5, 1998 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9650666

RESUMEN

Regarding the development of a centrifugal blood pump to be connected directly with small diameter tubings for pediatric use while minimizing hemolysis, we have studied the inlet port side configurations of a pump using both a hemolysis test and computational fluid dynamics (CFD) analysis. We have conducted a hemolysis test on 2 models. The tapered shape inlet has proven to be lower in the index of hemolysis (IH) than the straight shape. CFD analyses utilizing expanded flow paths indicated that the flow velocity decreased as the fluid path became larger within the tapered nozzle. When entering the pump chamber, the flow rushed in at a greater velocity through the straight nozzle due to its small diameter. The straight shape showed an abrupt change in pressure around the entrance of the pump chamber while the tapered shape did not. The flow inlet angle of the straight model was observed to be larger than that of the tapered model because of its smaller turning radius.


Asunto(s)
Circulación Extracorporea/instrumentación , Velocidad del Flujo Sanguíneo , Presión Sanguínea , Viscosidad Sanguínea , Volumen Sanguíneo , Niño , Simulación por Computador , Diseño de Equipo , Hemólisis , Hemorreología , Humanos , Intubación/instrumentación , Rotación , Propiedades de Superficie
16.
Pflugers Arch ; 449(1): 42-55, 2004 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15293051

RESUMEN

This study elucidates the role of cell volume in contractions of endothelium-denuded vascular smooth muscle rings (VSMR) from the rat aorta. We observed that hyposmotic swelling as well as hyper- and isosmotic shrinkage led to VSMR contractions. Swelling-induced contractions were accompanied by activation of Ca2+ influx and were abolished by nifedipine and verapamil. In contrast, contractions of shrunken cells were insensitive to the presence of L-type channel inhibitors and occurred in the absence of Ca2+ o. Thirty minutes preincubation with bumetanide, a potent Na+, K+, CI- cotransport (NKCC) inhibitor, decreased Cl(-)i content, nifedipine-sensitive 45Ca uptake and contractions triggered by modest depolarization ([K+]o = 36 mM). Elevation of [K+]o to 66 mM completely abolished the effect of bumetanide on these parameters. Bumetanide almost completely abrogated phenylephrine-induced contraction, partially suppressed contractions triggered by hyperosmotic shrinkage, but potentiated contractions of isosmotically shrunken VSMR. Our results suggest that bumetanide suppresses contraction of modestly depolarized cells via NKCC inhibition and Cl(-)i-mediated membrane hyperpolarization, whereas augmented contraction of isosmotically shrunken VSMR by bumetanide is a consequence of suppression of NKCC-mediated regulatory volume increase. The mechanism of bumetanide inhibition of contraction of phenylephrine-treated and hyperosmotically shrunken VSMR should be examined further.


Asunto(s)
Canales de Calcio Tipo L/metabolismo , Tamaño de la Célula , Cloruros/metabolismo , Contracción Muscular/fisiología , Músculo Liso Vascular , Potasio/metabolismo , Sodio/metabolismo , Animales , Aorta/anatomía & histología , Aorta/metabolismo , Células Cultivadas , Medios de Cultivo/química , Soluciones Hipertónicas , Soluciones Hipotónicas , Técnicas In Vitro , Músculo Liso Vascular/citología , Músculo Liso Vascular/metabolismo , Isoformas de Proteínas/metabolismo , Ratas , Ratas Wistar , Simportadores de Cloruro de Sodio-Potasio/metabolismo , Miembro 2 de la Familia de Transportadores de Soluto 12
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA