RESUMEN
Domestic wells serve as the primary drinking-water source for rural residents in the northern Appalachian Basin (NAB), despite a limited understanding of contaminant distributions in groundwater sources. We employ a newly collected dataset of 216 water samples from domestic wells in Ohio and West Virginia and an integrated contaminant-source attribution method to describe water quality in the western NAB and characterize key agents influencing contaminant distributions. Our results reveal arsenic and nitrate concentrations above federal maximum contaminant levels (MCLs) in 6.8 and 1.3% of samples and manganese concentrations above health advisory in 7.3% of samples. Recently recharged groundwaters beneath upland regions appear vulnerable to surface-related impacts, including nitrate pollution from agricultural activities and salinization from road salting and domestic sewage sources. Valley regions serve as terminal discharge points for long-residence-time groundwaters, where mixing with basin brines is possible. Arsenic impairments occurred in alkaline groundwaters with major-ion compositions altered by ion exchange and in low-oxygen metal-rich groundwaters. Mixing with as much as 4-10% of mine discharge-like waters was observed near coal mining operations. Our study provides new insights into key agents of groundwater impairment in an understudied region of the NAB and presents an integrated approach for contaminant-source attribution applicable to other regions of intensive resource extraction.
Asunto(s)
Arsénico , Agua Subterránea , Contaminantes Químicos del Agua , Arsénico/análisis , Monitoreo del Ambiente , Manganeso , Nitratos , Compuestos Orgánicos , Oxígeno , Aguas del Alcantarillado , Contaminantes Químicos del Agua/análisisRESUMEN
Nowadays, there is a tendency in olive production systems to reduce tillage or keep a vegetative cover to reduce soil erosion and degradation. However, there is scarce information on the effects of different soil management systems (SMS) in soil bacterial community composition of olive groves. In this study, we have evaluated the effects of soil type and different SMS implemented to control weeds in the structure and diversity of bacterial communities of 58 soils in the two geographic areas that best represent the organic olive production systems in Spain. Bacterial community composition assessed by frequency and intensity of occurrence of terminal restriction profiles (TRFs) derived from terminal restriction fragment length polymorphism (T-RFLP) analysis of amplified 16S ribosomal deoxyribonucleic acid were strongly correlated with soil type/field site (Eutric/Calcaric) that differed mainly in soil particle size distribution and soil pH, followed by a strong effect of SMS, in that order. Canonical discriminant (CD) analysis of TRFs properly classified all of the olive orchard soils as belonging to their respective soil type or SMS. Furthermore, only a small set of TRFs were enough to clearly and significantly differentiate soil samples according to soil type or SMS. Those specific TRFs could be used as bioindicators to assess the effect of changes in SMS aimed to enhance soil quality in olive production systems.
Asunto(s)
Bacterias/aislamiento & purificación , Biodiversidad , Olea/crecimiento & desarrollo , Microbiología del Suelo , Suelo/química , Bacterias/clasificación , Bacterias/genética , Datos de Secuencia Molecular , Agricultura Orgánica , Filogenia , EspañaRESUMEN
The failure of a tailing pond dam at the Aznalcóllar pyrite mine (SW Spain) in April 1998 released a toxic spill affecting approximately 4300 ha along the Agrio and Guadiamar valleys. Two years later, we have studied yield and concentration of mineral nutrients and trace elements in sunflower plants grown in the spill-affected soil, and in an adjacent unaffected soil as comparison. The study has been carried out in plants at seedling (V4) and mature (R8) stages. Shoot and root biomass of sunflower seedlings was significantly smaller in the affected soil than in the unaffected soil, but there was no significant difference at the mature stage. Oil production was greater in the spill-affected plants. We have not detected any 'fertilising' effect caused by the acid waters of the spill on the main nutrient (N, P and Ca) acquisition, as documented in 1998 for sunflower plants flooded by the spill. Sunflower plants growing in the spill-affected soil reached adequate levels of nutrients. None of the trace elements measured-As, Cd, Cu, Pb and Tl-reached levels either phytotoxic or toxic for humans or animals in seeds and the above-ground part of the spill-affected plants. We evaluate the potential use of sunflower plants for phytoremediation. The potential for phytoextraction is very low; however, it may be used for soil conservation. The production of oil (usable for industrial purposes) may add some value to this crop.
Asunto(s)
Helianthus/crecimiento & desarrollo , Metales Pesados/farmacocinética , Minería , Contaminantes del Suelo/efectos adversos , Oligoelementos/farmacocinética , Biodegradación Ambiental , Biomasa , Calcio/farmacocinética , Contaminación Ambiental/prevención & control , Helianthus/química , Hierro , Nitrógeno/farmacocinética , Fósforo/farmacocinética , SulfurosRESUMEN
El hídrops fetal temprano es un fenómeno frecuente que forma parte de numerosos procesos patológicos. Sin embargo, la tasa de diagnósticos se encuentra por debajo de su incidencia. Los hallazgos ecográficos indirectos relacionados con fallo cardíaco de diferente origen son más frecuentes en el primer trimestre. Es estos casos, el aumento del pliegue nucal suele ser el primer signo ecográfico de hídrops temprano. En el estudio realizado sobre 30 casos en los que se determinó el cariotipo fetal por un pliegue nucal mayor de 3 mm antes de la semana 14 de gestación como indicación, el índice de cromosomopatías fue del 36,7 frente al 3,1 por ciento de cariotipos anormales obtenidos cuando la indicación fue otra. Además, se observó un 50 por ciento de anomalías asociadas entre los que presentaron algún signo temprano de hídrops y un 47 por ciento de mortalidad fetal asociada. La medición del pliegue nucal ofrece la oportunidad de realizar un cribado temprano de aneuploidías, cardiopatías u otras afecciones fetales (AU)
Asunto(s)
Femenino , Masculino , Humanos , Hidropesía Fetal/diagnóstico , Protocolos Clínicos , Biopsia/métodos , Abdomen/patología , Abdomen , Cariotipo XYY/diagnóstico , Mortalidad Fetal , Aberraciones Cromosómicas/diagnóstico , Edad Gestacional , Factores de Riesgo , Marcadores Genéticos/fisiología , Aberraciones Cromosómicas/fisiopatologíaRESUMEN
Protein methylation at arginines is ubiquitous in eukaryotes and affects signal transduction, gene expression and protein sorting. Hmt1/Rmt1, the major arginine methyltransferase in yeast, catalyzes methylation of arginine residues in several mRNA-binding proteins and facilitates their export from the nucleus. We now report the crystal structure of Hmt1 at 2.9 A resolution. Hmt1 forms a hexamer with approximate 32 symmetry. The surface of the oligomer is dominated by large acidic cavities at the dimer interfaces. Mutation of dimer contact sites eliminates activity of Hmt1 both in vivo and in vitro. Mutating residues in the acidic cavity significantly reduces binding and methylation of the substrate Npl3.
Asunto(s)
Metiltransferasas/química , Metiltransferasas/metabolismo , Saccharomyces cerevisiae/enzimología , Secuencia de Aminoácidos , Sustitución de Aminoácidos/genética , Sitios de Unión , Western Blotting , Cromatografía en Gel , Cristalografía por Rayos X , Metilación de ADN , Dimerización , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Péptidos y Proteínas de Señalización Intracelular , Metiltransferasas/genética , Modelos Moleculares , Datos de Secuencia Molecular , Unión Proteica , Estructura Cuaternaria de Proteína , Estructura Secundaria de Proteína , Proteína-Arginina N-Metiltransferasas , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Saccharomyces cerevisiae/genética , Alineación de Secuencia , Eliminación de Secuencia/genética , Electricidad EstáticaRESUMEN
An epizootiological survey of leishmaniosis, coccidiosis and parasitic helminths in 67 foxes (Vulpes vulpes) was conducted in Guadalajara (central Spain). Examination for parasitic protozoa revealed prevalences of 74% Leishmania (determined by molecular methods) and 2.9% coccidia oocysts (fecal flotation). Survey of parasitic helminths (fecal flotation/necropsy) demonstrated the presence of nine species, including six nematodes, two cestodes and one trematode. Nematodes were the most common parasites of foxes, followed by cestodes and trematodes. Greater levels of nematodes like Uncinaria, with a free-living stage in its life-cycle, were found in foxes in areas where moist soils were likely to exist, in contrast to areas of semiarid characteristics, where Toxascaris leonina or Trichuris vulpis were predominant. With regard to helminths of importance as human pathogens, trichinoscopy revealed the presence of a relatively high number of foxes (8.9%) infected with Trichinella spiralis. Finally, Toxocara canis infection was less frequent (4.4%) than trichinellosis.
Asunto(s)
Zorros/parasitología , Enfermedades Parasitarias en Animales/epidemiología , Animales , Coccidiosis/epidemiología , Coccidiosis/veterinaria , Reservorios de Enfermedades , Heces/parasitología , Helmintiasis Animal/epidemiología , Leishmaniasis/epidemiología , Leishmaniasis/veterinaria , Infecciones por Nematodos/epidemiología , Infecciones por Nematodos/veterinaria , Prevalencia , España/epidemiologíaRESUMEN
High density oligonucleotide arrays offer tremendous potential to study gene changes occurring in disease states. The authors described the first case of using a custom designed high density oligonucleotide probe array containing 750 genes to monitor the changes in mRNA transcript levels occurring after focal ischemia for a period of 3 hours. Permanent middle cerebral artery occlusion in the rat resulted in neuronal degeneration in the dorsolateral cortex and striatum over a time course of 24 hours. Comparing the changes in hybridization levels in the frontal and parietal cortices and the striatum, between the ipsilateral and contralateral sides of the brain using the probe arrays resulted in the up-regulation of 24 genes, which showed greater than a twofold change. Very few genes were found to be downregulated after the ischemic insult. Many of the immediate early genes (IEGs) such as c-fos, NGFI-A, NGFI-C, and Krox-20 were found to be robustly upregulated in the three different regions studied. Other genes that were up-regulated in perifocal regions included Arc, Inhibin-beta-A, and the phosphatases MKP-1 and MKP-3. The hybridization signal intensity from the probe arrays enabled quantification of many genes relative to one another, and robust changes in expression were obtained with very little interanimal variability. Furthermore, the authors were able to validate the increased expression of NGFI-C and Arc using in situ hybridization. This represented the first example of using high density oligonucleotide probe arrays in studying the expression of many genes in parallel and in discrete brain regions after focal ischemia.
Asunto(s)
Isquemia Encefálica/genética , Expresión Génica , Transcripción Genética , Animales , Encéfalo/fisiopatología , Proteínas del Citoesqueleto/genética , Proteínas de Unión al ADN/genética , Regulación hacia Abajo , Hibridación in Situ , Masculino , Proteínas del Tejido Nervioso/genética , Sondas de Oligonucleótidos , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Distribución Tisular , Factores de Transcripción/genética , Regulación hacia ArribaRESUMEN
Cyclooxygenase-2, a key enzyme in prostanoid synthesis, is induced by inflammatory stimuli and it is associated with cell death after cerebral ischemia. Here we evaluated whether cyclooxygenase-2 was induced after a short (10-min) episode of focal ischemia, mild enough not to cause inflammation or cell death. One-hour ischemia leading to brain infarct was studied for comparative purposes. Induction of cyclooxygenase-2 mRNA and protein was detected after both 10-min and 1-h ischemia. However, signs of edema were only apparent after 1-h, but not 10-min ischemia, and only rats subjected to 1-h ischemia had developed brain infarct at 4 days. Therefore, cyclooxygenase-2, not linked with neural cell death or inflammation, is induced after focal ischemia.
Asunto(s)
Isquemia Encefálica/enzimología , Encéfalo/enzimología , Isoenzimas/biosíntesis , Prostaglandina-Endoperóxido Sintasas/biosíntesis , Animales , Arteriopatías Oclusivas , Encéfalo/patología , Isquemia Encefálica/complicaciones , Isquemia Encefálica/patología , Infarto Cerebral/enzimología , Infarto Cerebral/etiología , Infarto Cerebral/patología , Ciclooxigenasa 2 , Inducción Enzimática , Inflamación/patología , Isoenzimas/genética , Neuronas/patología , Prostaglandina-Endoperóxido Sintasas/genética , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
The neuroprotective effects of a systemically active, potent, group II selective metabotropic glutamate receptor agonist, LY354740, was assessed in the middle cerebral artery occlusion model of focal ischaemia in rats. LY354740 (0.3, 3.0 or 30.0 mg/kg) was administered subcutaneously (s.c.) 30 min prior to and 3 hours after the induction of ischaemia. Twenty four hours after the ischaemic insult, the brains were processed for the evaluation of infarct volumes. No significant reduction in infarct volumes were observed in treated animals at any of the doses investigated. These data provide no support for the view that group II metabotropic glutamate receptors have a major influence on ischaemic damage in this model.
Asunto(s)
Isquemia Encefálica/patología , Compuestos Bicíclicos con Puentes/farmacología , Agonistas de Aminoácidos Excitadores/farmacología , Fármacos Neuroprotectores/farmacología , Receptores de Glutamato Metabotrópico/agonistas , Animales , Encéfalo/efectos de los fármacos , Encéfalo/patología , Infarto Cerebral/patología , Relación Dosis-Respuesta a Droga , Masculino , Ratas , Ratas Endogámicas F344RESUMEN
Severe transient focal cerebral ischemia causes brain infarction with a strong glial reaction. We have studied whether postischemic reactive glial cells express epidermal growth factor receptor (EGFR) following middle cerebral artery occlusion in the rat. We have also looked for signs of proliferating activity, as EGFR is known to be involved in cell growth and proliferation in certain non-neural cells. EGFR was studied using three different antibodies which were found to stain for a tyrosine-phosphorylated protein (p170) corresponding to the membrane-anchored EGFR. Neurons of the control brain were strongly immunoreactive to EGFR, but a decrease of EGFR-immunoreactivity was seen in the ipsilateral brain side from 24 h postischemia due to neuronal loss. However, the presence of abundant glial cells strongly immunoreactive to EGFR became apparent in this area from 4 days postischemia onward. The use of microglial (lectin or OX-42) and astroglial (GFAP) markers showed that these postischemic EGFR-stained cells were reactive microglia/macrophages and astroglia. The subcellular localization of EGFR in reactive microglia/macrophages was compatible with the network of the Golgi apparatus, as revealed with an antibody against a peripheral membrane-bound protein of the Golgi. The presence of abundant proliferating cells in the ischemic brain was detected from 4 days postischemia with an antibody against proliferating cell nuclear antigen. Proliferating reactive microglia/macrophages were abundant within the infarcted brain side, whereas proliferating astrocytes were found mainly in the immediate periphery of the infarct limiting the necrotic area from the undamaged tissue. These proliferating cells were immunoreactive to EGFR. The results show the presence of EGFR in postischemic reactive glial cells and suggest that EGFR-dependent pathways mediate signal transduction in reactive glia following transient focal cerebral ischemia.
Asunto(s)
Receptores ErbB/metabolismo , Ataque Isquémico Transitorio/metabolismo , Neuroglía/metabolismo , Neuroglía/patología , Animales , Arteriopatías Oclusivas/metabolismo , Arteriopatías Oclusivas/patología , División Celular , Enfermedades Arteriales Cerebrales/metabolismo , Enfermedades Arteriales Cerebrales/patología , Ataque Isquémico Transitorio/patología , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
The cerebral stress response is examined following a variety of pathological conditions such as focal and global ischemia, administration of excitotoxins, and hyperthermia. Expression of 72 kDa heat shock protein (Hsp70) and hsp70 mRNA, the mechanism underlying induction of hsp70 mRNA involving activation of heat shock factor 1, and inhibition of cerebral protein synthesis are different aspects of the stress response considered here. The results are compared with those in the literature on induction, transcriptional regulation, expression, and cellular location of Hsp70, with a view to getting more insight into the function of the stress response in the injured brain. The present results illustrate that Hsp70 can be expressed in cells affected at various degrees following an insult that will either survive or dic as the brain lesion develops, depending on the severity of cell injury. This indicates that, under certain circumstances, synthesized Hsp70 might be necessary but not sufficient to ensure cell survival. Other situations involve uncoupling between synthesis of hsp70 mRNA and protein, probably due to very strict protein synthesis blockade, and often result in cell loss. Cells eventually will die if protein synthesis rates do not go back to normal after a period of protein synthesis inhibition. The stress response is a dynamic event that is switched on in neural cells sensitive to a brain insult. The stress response is, however, tricky, as affected cells seem to need it, have to deal transiently with it, but eventually be able to get rid of it, in order to survive. Putative therapeutic treatments can act either selectively, potentiating the synthesis of Hsp70 protein and recovery of protein synthesis, or preventing the stress response by deadening the insult severity.
Asunto(s)
Axones/fisiología , Lesiones Encefálicas/metabolismo , Proteínas de Choque Térmico/metabolismo , Estrés Fisiológico/metabolismo , Animales , Transporte Biológico/fisiología , Proteínas del Choque Térmico HSP72 , Biosíntesis de Proteínas , Proteínas/efectos de los fármacos , Transcripción GenéticaRESUMEN
Occlusion of the middle cerebral artery (MCA) causes a reduction of cerebral blood flow (CBF), which shows a progressive decrease from the periphery to the core of the MCA territory. The severity of ischemia is dependent on the duration of the ischemic episode and degree of CBF reduction. Fixing the ischemic episode to 1 h, we have examined whether or not cortical infarct size was related to the degree of CBF reduction in a perifocal cortical area in rats. One-hour intraluminal MCA occlusion accompanied with bilateral common carotid artery (CCA) occlusion (three-vessel occlusion/reperfusion model) was carried out in Sprague-Dawley rats and CBF was monitored with laser-Doppler flowmetry in the fronto-parietal cortex, an area which is perifocal to the core of the MCA territory. Finally, infarct size was measured 7 days later and was related to the corresponding CBF decrease. Sequential ipsilateral CCA, MCA and contralateral CCA occlusions produced reductions of CBF to 96%, 52% and 33% of baseline, respectively. Cortical infarct volume was found to be dependent on the corresponding reduction of perifocal cortical CBF during the ischemic episode. These results show that the reduction of CBF in the periphery of the MCA territory during 1-h focal ischemia determines infarct size in a three-vessel occlusion/reperfusion model.
Asunto(s)
Infarto Cerebral/patología , Circulación Cerebrovascular/fisiología , Daño por Reperfusión/patología , Animales , Arteriopatías Oclusivas/patología , Arteriopatías Oclusivas/fisiopatología , Enfermedades de las Arterias Carótidas/patología , Enfermedades de las Arterias Carótidas/fisiopatología , Arterias Cerebrales , Infarto Cerebral/fisiopatología , Flujometría por Láser-Doppler , Masculino , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/fisiopatologíaRESUMEN
Dopaminergic neurons of the substantia nigra pars compacta were examined in the rat brain following striatal infarction subsequent to transient focal cerebral ischemia. Rats had the middle cerebral artery occluded for 2 h or were sham-operated, and tyrosine hydroxylase immunoreactivity was evaluated by Western blot and immunohistochemistry at different times ranging from 1 to 60 days after ischemia. The number of tyrosine hydroxylase-immunoreactive cells in the substantia nigra pars compacta was counted under the light microscope and compared to that in the contralateral side and controls. No changes of tyrosine hydroxylase immunoreactivity were detected in the ipsilateral versus the contralateral substantia nigra of sham-operated rats or 1 day after ischemia. However, a statistically significant reduction of tyrosine hydroxylase-immunoreactive cells became apparent in the ipsilateral compared with the contralateral substantia nigra at 7 and 14 days after ischemia. This reduction showed a clear recovery at 30 days after ischemia, and no signs of difference between the ipsilateral and the contralateral side were apparent by 60 days. Therefore, the reduction of tyrosine hydroxylase immunoreactivity in the ipsilateral substantia nigra was only transiently seen from 1 to 2 weeks following ischemia. The observed loss of tyrosine hydroxylase was not accompanied by signs of cell death or gliosis in the ipsilateral pars compacta. The present results show a transitory reduction of tyrosine hydroxylase immunoreactivity in the ipsilateral substantia nigra pars compacta after focal ischemia and suggest that striatal infarction causes a transient deficit of dopaminergic function.
Asunto(s)
Infarto Cerebral/metabolismo , Cuerpo Estriado/irrigación sanguínea , Ataque Isquémico Transitorio/metabolismo , Sustancia Negra/enzimología , Tirosina 3-Monooxigenasa/inmunología , Animales , Anticuerpos Monoclonales , Arteriopatías Oclusivas/metabolismo , Recuento de Células , Infarto Cerebral/etiología , Cuerpo Estriado/patología , Lateralidad Funcional/fisiología , Proteína Ácida Fibrilar de la Glía/análisis , Proteína Ácida Fibrilar de la Glía/inmunología , Ataque Isquémico Transitorio/complicaciones , Masculino , Neuronas/química , Neuronas/citología , Neuronas/enzimología , Ratas , Ratas Sprague-Dawley , Sustancia Negra/citología , Tirosina 3-Monooxigenasa/análisisRESUMEN
Stat3, a member of the family of cytoplasmic signal transducers and activators of transcription, was found in the rat brain in vivo under physiological conditions and was stimulated following transient focal cerebral ischaemia. A transient episode of middle cerebral artery occlusion induced a strong microglial response in the areas undergoing neural cell death from 4 days after middle cerebral artery occlusion. This was accompanied by increased expression of Stat3 in the ipsilateral cortex and striatum, as revealed by Western blotting of tissue extracts. Immunohistochemistry showed strong induction of Stat3 in reactive microglial cells 4, 7 and 15 days after cerebral ischaemia. Stat3 was seen in the microglia cytoplasm, but in many microglial cells immunoreactivity was also distributed within the nucleus. These results suggest that Stat3 mediates signal transduction and activates transcription in reactive microglia in vivo following brain ischaemia.
Asunto(s)
Corteza Cerebral/metabolismo , Cuerpo Estriado/metabolismo , Proteínas de Unión al ADN/metabolismo , Ataque Isquémico Transitorio/metabolismo , Microglía/metabolismo , Transactivadores/metabolismo , Animales , Western Blotting , Encéfalo/patología , Histocitoquímica , Inmunohistoquímica , Ataque Isquémico Transitorio/patología , Lectinas , Masculino , Ratas , Ratas Sprague-Dawley , Factor de Transcripción STAT3RESUMEN
Cortical infarction produces secondary neuronal damage in the thalamus. In this study we examined the thalamus of the rat following 2 h occlusion of the middle cerebral artery (MCA), and found degeneration and gliosis in the ipsilateral ventropostero-medial thalamic nucleus in those rats that showed cortical infarction 7 and 14 days after occlusion. This was accompanied by isolated cells with fragmented DNA, as revealed by in situ labelling of nuclear DNA fragmentation, and showing morphological features of apoptosis, i.e. chromatin condensation, extreme nuclear shrinkage and apoptotic bodies. In addition, cells immunoreactive for c-Jun showing morphological signs of apoptosis were observed. These results provide evidence of apoptosis in the ipsilateral thalamus following cortical infarction, and suggest that c-Jun is involved in this process.
Asunto(s)
Apoptosis/fisiología , Infarto Cerebral/metabolismo , Infarto Cerebral/patología , Proteínas Proto-Oncogénicas c-jun/biosíntesis , Tálamo/metabolismo , Tálamo/patología , Animales , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patología , Arterias Cerebrales/fisiología , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Proteína Ácida Fibrilar de la Glía/metabolismo , Inmunohistoquímica , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
Expression of cyclooxygenase-2 (cox-2) mRNA and inducible heat-shock protein-70 (hsp-70) mRNA was studied with in situ hybridization techniques at 30 min and 4 h following 1 h transient middle cerebral artery (MCA) occlusion in the rat brain. In addition, immunoreactivity for cox-2 was studied after 8 h of reperfusion. Induction of hsp-70 and cox-2 mRNA was found in the brain side ipsilateral to MCA occlusion. Hsp-70 mRNA was induced in the parietal cortex and striatum within the territory of the occluded MCA. Induction of cox-2 mRNA was particularly seen in cortical layer II in the brain side ipsilateral to MCA occlusion. At 30 min of reperfusion, areas showing cox-2 mRNA induction included the cingulate and frontal cortices located perifocally to the areas showing hsp-70 mRNA induction, and the piriform cortex. At 4 h of reperfusion, induction of cox-2 mRNA was seen within the parietal cortex. At 8 h of reperfusion, immunoreactivity for cox-2 was mainly seen in the ipsilateral cortex. These results demonstrate that transient focal ischemia induces the expression of cox-2 mRNA and protein in discrete areas of the rat brain during reperfusion, which might lead to local increases of arachidonic acid metabolism.
Asunto(s)
Encéfalo/enzimología , Ataque Isquémico Transitorio/enzimología , Prostaglandina-Endoperóxido Sintasas/biosíntesis , ARN Mensajero/biosíntesis , Animales , Secuencia de Bases , Inducción Enzimática/fisiología , Proteínas HSP70 de Choque Térmico/biosíntesis , Hibridación in Situ , Masculino , Datos de Secuencia Molecular , Ratas , Ratas Sprague-Dawley , ReperfusiónRESUMEN
HSP-70 was induced in the gerbil following 20 min of forebrain ischemia. The induction, as revealed with immunohistochemistry, is stronger and longer-lasting in CA3 and dentate gyrus than in CA1. Most neurons in this region, except GABAergic interneurons containing the calcium-binding protein parvalbumin, eventually cease to live as a result of delayed cell death. Double-labeling of inducible HSP-70 and parvalbumin has shown that no co-localization occurs in the hippocampus and neocortex of the gerbil in this model of transient forebrain ischemia. These results show that different thresholds of sensitivity and vulnerability exist for different subpopulations of neurons in the ischemic hippocampus, and suggest that HSP-70 protein induction is probably not essential for the survival of particular neuronal subpopulations subjected to transient ischemia.
Asunto(s)
Proteínas HSP70 de Choque Térmico/biosíntesis , Hipocampo/metabolismo , Hipocampo/patología , Ataque Isquémico Transitorio/metabolismo , Ataque Isquémico Transitorio/patología , Neuronas/fisiología , Parvalbúminas/metabolismo , Animales , Supervivencia Celular/fisiología , Giro Dentado/metabolismo , Giro Dentado/patología , Gerbillinae , Inmunohistoquímica , Interneuronas/metabolismo , Interneuronas/fisiología , Degeneración Nerviosa/fisiología , Ácido gamma-Aminobutírico/fisiologíaRESUMEN
The regional expression of inducible 72 kDa heat shock protein (HSP-70), HSP-70 mRNA and the neuropathological outcome of their expression were examined in the rat brain following systemic administration of kainic acid (9 mg/kg), and also after pretreatment with the non-competitive N-methyl-D-aspartate antagonist MK-801 (1 mg/kg). Five hours after administration of kainic acid alone, dense expression of HSP-70 mRNA was found within the limbic system, mainly in the hippocampus, piriform and entorhinal cortices, amygdaloid complex, thalamic nuclei, subiculum and in other cortical areas in rats that had shown convulsive behaviour. At 24 h, HSP-70 immunoreactivity was seen in most areas previously expressing HSP-70 mRNA, except the piriform and entorhinal cortices and several ventral nuclei of the amygdaloid complex. Histopathological examination at 24 h revealed marked cell loss in these latter regions and less severe histopathological changes in other areas of the limbic system in brains of convulsive rats. No alterations were apparent in non-convulsive rats. The percentage of rats showing convulsive behaviour with kainic acid was reduced from 74 to 4% following pretreatment with MK-801. In addition, MK-801 inhibited the kainic acid-induced expression of HSP-70 mRNA and protein in certain brain regions, notably the cortex, the pyramidal cell layer of CA1, and discrete thalamic nuclei. However, HSP-70 mRNA induction was sustained in the pyramidal cell layer of CA3, the amygdaloid complex and the subiculum, despite the fact that none of these rats convulsed. MK-801 prevented necrosis in all rats examined except the single rat that had shown convulsive behaviour. These results show that early regional expression of inducible HSP-70 mRNA allows the visualization of regions affected by kainic acid and maps regions inhibited by MK-801. In addition, the results identify brain regions putatively involved in the manifestation of limbic convulsions. Furthermore, these data illustrate that the induction of HSP-70 mRNA is not predictive of cell death or survival.