RESUMEN
OBJECTIVES: We investigated the effectiveness of cycle ergometer training and resistance training to enhance the efficiency of standard care to improve walking ability, muscular strength of the lower limbs, cardiovascular endurance and health-related quality of life during inpatient rehabilitation in intensive care unit acquired weakness. MATERIALS & METHODS: Thirty-nine patients with severe to moderate walking disability were enrolled in one of the three experimental groups: (a) ergometer training group, (b) resistance training group and (c) control group (standard care only). Intervention was applied 5 days a week over a 4-week period during inpatient neurological rehabilitation. We evaluated walking ability (Functional Ambulation Category test, timed up and go test, 10-metre walk test and 6-minute walk test), muscle strength (Medical Research Council and maximum muscle strength tests), cardiovascular endurance and muscular endurance of the lower limbs at the fatigue threshold (physical working capacity at fatigue threshold) and quality of life (medical outcomes study SF-36 form). All tests were performed at baseline, after two weeks of treatment and at the end of the 4-week intervention period. RESULTS: Ergometer training and resistance training enhanced the effectiveness of standard care in order to improve (a) lower limb muscle strength, (b) walking ability and (c) cardiorespiratory fitness during inpatient rehabilitation of intensive care acquired weakness. In addition, ergometer training may be superior to resistance training. CONCLUSIONS: Our data encourage more research to develop and implement these training tools in rehabilitation programmes for intensive care acquired weakness.
Asunto(s)
Enfermedad Crítica/rehabilitación , Ejercicio Físico , Debilidad Muscular/etiología , Debilidad Muscular/rehabilitación , Entrenamiento de Fuerza/métodos , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Unidades de Cuidados Intensivos , Masculino , Persona de Mediana Edad , Limitación de la Movilidad , Calidad de Vida , Resultado del TratamientoRESUMEN
This paper studies money demand in Switzerland under free banking before the establishment of the Swiss National Bank. We find that, in addition to income, the banks' balance-sheet-to-GDP ratio and the number of banks were important determinants of long-run money demand. The former variable also played an important role in the monetary adjustment process. We also detect a strong positive long-run impact of real income on the bank's balance-sheet-total-to-GDP ratio and a strong long-run influence of real income and the interest rate spread on the number of banks.
RESUMEN
Ten years after the worst financial crisis of the post-war period, Switzerland has established a Too-Big-To-Fail (TBTF) framework. Under this framework, the two large Swiss banks are subject to substantial capital requirements. It is not obvious whether the TBTF capital requirements are sufficient to prevent banks from plunging the country into a financial crisis once again. We estimate the social costs and benefits of higher capital requirements for the two large Swiss banks and derive socially optimal capital ratios from the cost-benefit trade-off. Our results show that Swiss TBTF capital requirements still fall short of socially optimal capital ratios.
RESUMEN
Glutamate is the major excitatory transmitter in the CNS and plays distinct roles in a number of developmental events. Its extracellular concentration, which mediates these activities, is regulated by glutamate transporters in glial cells and neurons. In the present study, we have used nonradioactive in situ hybridization, immunocytochemistry, and immunoblotting to show the cellular and regional expression of the high-affinity glutamate transporters GLAST (EAAT1) and generic GLT1 (EAAT2; glial form of GLT1) in the rat hippocampus during postnatal development (P1-60). The results of transporter expression were compared with the localization and activity pattern of glutamate dehydrogenase (GDH), an important glutamate-metabolizing enzyme. The study showed that both transporters and GDH were demonstrable at P1 (day of birth). The expression of GLAST (detected by in situ hybridization and immunocytochemistry) in the early postnatal development was higher than GLT1. Thereafter, the expression of both transporters increased, showing adult levels at between P20 and P30 (detected by in situ hybridization and immunoblotting). At these time points, the expression of GLT1 appeared to be significantly higher than the GLAST expression. GLT1 and GLAST proteins were demonstrable only in astrocytes. The increase of GDH activities (steepest increase from P5-P8), which were localized preferentially in astrocytes, was in agreement with the increase of transporter expression, preferentially with that of GLT1. These observations suggest that the extent of glutamate transporter expression and of glutamate-metabolizing GDH activity in astrocytes is intimately correlated with the formation of glutamatergic synapses in the developing hippocampus.
Asunto(s)
Sistema de Transporte de Aminoácidos X-AG/metabolismo , Astrocitos/metabolismo , Transportador 2 de Aminoácidos Excitadores/metabolismo , Regulación del Desarrollo de la Expresión Génica , Glutamato Deshidrogenasa/metabolismo , Hipocampo/metabolismo , Simportadores/metabolismo , Envejecimiento/metabolismo , Sistema de Transporte de Aminoácidos X-AG/genética , Animales , Animales Recién Nacidos , Diferenciación Celular/genética , Transportador 1 de Aminoácidos Excitadores , Transportador 2 de Aminoácidos Excitadores/genética , Proteínas de Transporte de Glutamato en la Membrana Plasmática , Ácido Glutámico/metabolismo , Hipocampo/crecimiento & desarrollo , Masculino , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Simportadores/genética , Sinapsis/genética , Sinapsis/metabolismo , Transmisión Sináptica/genética , Regulación hacia Arriba/genéticaRESUMEN
Glutamate and aspartate play important roles in the intermediary metabolism of the myocardium and have been shown to improve cardiac recovery after hypoxia or ischemia. Limited data are available about the expression of glutamate transporters that are involved in the uptake of glutamate and aspartate in cardiomyocytes. In this study, non-radioactive in situ hybridization (ISH) using complementary RNA probes was applied to detect the glutamate transporters GLT1 variant (GLT1v) and EAAC1 mRNA in rat cardiomyocytes. The transporter proteins were demonstrated by Western blotting and immunocytochemistry using affinity-purified antibodies against transporter peptides. ISH and immunocytochemistry showed that both glutamate transporters are coexpressed in cardiomyocytes. The ISH labeling indicates the distribution of transporter mRNA throughout the cytoplasm of cardiomyocytes. GLT1v and EAAC1 proteins, which showed in Western blots a molecular mass of approximately 60 kD, are strongly enriched and colocalized in the transverse (T)-tubular system of cardiomyocytes. These results may indicate that glutamate/aspartate uptake into cardiomyocytes could be mediated by the high-affinity transporters GLT1v and EAAC1. A high efficiency of glutamate/aspartate transport into cardiomyocytes could be achieved by their localization in the T-tubular system, which consists of tubular invaginations of the sarcolemma extending deep into the cell.
Asunto(s)
Sistema de Transporte de Aminoácidos X-AG/biosíntesis , Transportador 2 de Aminoácidos Excitadores/biosíntesis , Miocitos Cardíacos/metabolismo , Simportadores/biosíntesis , Animales , Western Blotting , Transportador 3 de Aminoácidos Excitadores , Proteínas de Transporte de Glutamato en la Membrana Plasmática , Immunoblotting , Hibridación in Situ , Masculino , Miocitos Cardíacos/ultraestructura , Ratas , Ratas WistarRESUMEN
l-Glutamate is the major excitatory transmitter in the vertebrate retina and plays a central role in the transmission of the various retinal neurons. Glutamate is removed from the extracellular space by at least five different glutamate transporters. The cellular distribution of these has been studied so far mainly using immunocytochemistry. In the present study non-radioactive in situ hybridisation using complementary RNA probes was applied in order to identify the cell types of rat retina and optic nerve expressing generic GLT1, GLT1 variant (GLT1v or GLT1B), GLAST and EAAC1. The results were compared with immunocytochemical data achieved using affinity-purified antibodies against transporter peptides. In the immunohistochemical studies the human retina was included. The study showed that in the rat retina GLT1v and EAAC1 were coexpressed in various cell types, i.e. photoreceptor, bipolar, horizontal, amacrine, ganglion and Müller cells, whereas GLAST was only detected in Müller cells and astrocytes. In the rat optic nerve GLT1v and EAAC1 were preferentially expressed in oligodendrocytes, whereas GLAST was revealed to be present mainly in astrocytes. Generic GLT1 could not be detected in the retina or optic nerve. The cellular distribution of glutamate transporters (only immunocytochemistry) in the human retina was very similar to that of the rat retina. Remarkable results of our studies were that generic GLT1 was not detectable in the rat (and human) retina and that GLT1v and EAAC1 were demonstrable in most cell types of the retina (including photoreceptor cells and their terminals).
Asunto(s)
Sistema de Transporte de Aminoácidos X-AG/biosíntesis , Ácido Glutámico/biosíntesis , Nervio Óptico/metabolismo , Retina/metabolismo , Células Amacrinas/química , Animales , Astrocitos/metabolismo , Transportador 1 de Aminoácidos Excitadores , Transportador 2 de Aminoácidos Excitadores/biosíntesis , Transportador 3 de Aminoácidos Excitadores , Proteínas de Transporte de Glutamato en la Membrana Plasmática , Humanos , Hibridación in Situ , Oligodendroglía/metabolismo , Células Fotorreceptoras/metabolismo , Ratas , Ratas Wistar , Células Ganglionares de la Retina/metabolismo , Simportadores/biosíntesisRESUMEN
The glutamate transporter GLT1 is essential in limiting transmitter signaling and restricting harmful receptor overstimulation. It has been shown recently that GLT1 exists in two forms, the generic GLT1 and a 3'-end-spliced variant of GLT1 (GLT1v), both with similar transport characteristics. To differentiate clearly the cellular distribution of both GLT1 forms in the cortex, specific cRNA probes for non-radioactive in situ hybridization were generated and applied to adult rat brain sections. The results were complemented by western and northern blot analyses and by immunocytochemical investigations using specific peptide antibodies against both GLT1 forms. The study confirmed that generic GLT1 mRNA was expressed predominantly in astrocytes and, to a small extent, in neurons, whereas GLT1 protein was detected only in cell membranes of astrocytes. On the other hand, GLT1v mRNA and protein were demonstrated predominantly in neurons and in non-astrocytic glial cells irrespective of the cortical areas studied. A cytoplasmic granular staining of neurons and astrocytes predominated in the demonstration of GLT1v protein. It is concluded that the cellular expression of the two GLT1 forms is complementary. The cytoplasmic vesicular distribution of GLT1v may represent an endogenous protective mechanism to limit glutamate-induced excitotoxicity.
Asunto(s)
Astrocitos/metabolismo , Corteza Cerebral/metabolismo , Transportador 2 de Aminoácidos Excitadores/metabolismo , Neuronas/metabolismo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Northern Blotting , Western Blotting , Corteza Cerebral/citología , Transportador 2 de Aminoácidos Excitadores/genética , Inmunohistoquímica , Hibridación in Situ , Masculino , Datos de Secuencia Molecular , ARN Mensajero/metabolismo , Ratas , Ratas WistarRESUMEN
Nitric oxide (NO) is a ubiquitous, cell-permeable intercellular messenger. The current concept assumes that NO diffuses freely through the plasma membrane into the cytoplasm of a target cell, where it activates its cytosolic receptor enzyme, soluble guanylyl cyclase (sGC). Recent evidence, however, suggests that cellular membranes are not only the predominant site of calcium-dependent NO synthesis, but also the site of its distribution and binding. Here we extend this concept to NO signalling to show that active sGC is partially associated with the plasma membrane in a state of enhanced NO sensitivity. After cellular activation, sGC further translocates to the membrane fraction in human platelets and associates with the NO-synthase-containing caveolar fraction in rat lung endothelial cells, in a manner that is dependent on the concentration of intracellular calcium. Our data suggest that the entire NO signalling pathway is more spatially confined than previously assumed and that sGC dynamically translocates to the plasma membrane, where it is sensitized to NO.
Asunto(s)
Calcio/metabolismo , Guanilato Ciclasa/metabolismo , Óxido Nítrico/metabolismo , Animales , Sitios de Unión , Plaquetas/metabolismo , Western Blotting , Membrana Celular/metabolismo , Citosol/metabolismo , Relación Dosis-Respuesta a Droga , Factores de Crecimiento Endotelial/metabolismo , Endotelio/patología , Humanos , Inmunohistoquímica , Pulmón/patología , Linfocinas/metabolismo , Miocardio/metabolismo , Unión Proteica , Transporte de Proteínas , Ratas , Transducción de Señal , Fracciones Subcelulares/metabolismo , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial VascularRESUMEN
Rapid uptake of synaptically released glutamate via the high affinity glutamate transporter 1 (GLT1; EAAT2) is important for limiting transmitter signalling and prevents a harmful receptor overstimulation. So far, in the adult brain GLT1 protein has only been detected in astrocytes. Here, we describe the cDNA cloning of a variant of GLT1 from rat brain which is generated by alternative splicing at the 3'-end of the GLT1 cDNA. Reverse transcription-polymerase chain reaction revealed that the GLT1 variant message was present not only in brain, but also in peripheral organs. Northern blot analysis showed that in brain the mRNA of GLT1 (approximately 11 kb) is predominant while in the retina the mRNA of GLT1 variant (approximately 12.5 kb) prevails. In situ hybridization using cRNA and oligonucleotide probes, and immunocytochemistry using an antibody against a synthetic GLT1v peptide were applied in order to identify the cell types expressing GLT1 variant in the adult rat nervous system. GLT1 variant is preferentially expressed in neurons of the CNS and PNS, but is also detected in glial cells (oligodendrocytes, ependymal cells, epithelial cells of the plexus choroideus, satellite cells, and Schwann cells). In contrast to GLT1, GLT1 variant was only occasionally detected in astrocytes. Immunolabelling revealed a preferentially cytoplasmic (frequently granular) staining of neurons and glial cells, suggesting a localization of GLT1 variant protein in vesicle membranes. The studies provide evidence that the cellular expression of the GLT1 variant in the CNS is almost complementary to that of GLT1 and that the GLT1 variant does not seem to be restricted to the CNS.