RESUMO
OBJECTIVE: Glibenclamide, Sulfonylurea receptor 1 antagonist, reduces brain edema after cerebral hemorrhage. However, the effects of glibenclamide on microglial activation and inflammatory cell infiltration after cerebral hemorrhage are unclear. The present study investigated the effect of glibenclamide on microglial activation and inflammatory cell infiltration in a rat cerebral hemorrhage model. METHODS: A collagenase intracerebral injection model was used to cause cerebral hemorrhage in rats. After injury, glibenclamide was continuously administered at 1.0µL/h for 24hours. We evaluated hematoma volume, brain edema, expression of ABCC8, galectin-3 and CD11b, and anti-Iba-1 antibody staining. RESULTS: Glibenclamide significantly reduced water content. Meanwhile, glibenclamide significantly reduced expression of galectin-3 and CD11b in the cerebral cortex and putamen on the bleeding side. Immunohistochemical staining confirmed that glibenclamide attenuated activation of microglia around the hematoma. CONCLUSIONS: Glibenclamide reduced microglial activation and infiltration of inflammatory cells, resulting in amelioration of cerebral edema.
Assuntos
Edema Encefálico , Animais , Ratos , Edema Encefálico/tratamento farmacológico , Edema Encefálico/etiologia , Hemorragia Cerebral/tratamento farmacológico , Galectina 3 , Glibureto/farmacologia , Glibureto/uso terapêutico , Hematoma , MicrogliaRESUMO
Sinus arrhythmia of the dog is unique because of the pronounced alternating beat-to-beat intervals. The clustering of these short (faster rates) and long (slower rates) intervals is not just influenced by autonomic input from breathing; sinus arrhythmia can persist in the panting or apneic dog. The multiplicity of central and peripheral influences on the sinus node complicates the unraveling of the mechanisms of sinus arrhythmia. Studies of the sinus node suggest that acetylcholine can slow cellular depolarization and block sinoatrial conduction. Electrocardiographic monitoring of the dog supports this notion in that abrupt bifurcation into short and long intervals develop at lower heart rates. We sought to determine whether this phenomenon could be recapitulated in canine atrial preparations perfused with acetylcholine and whether selective pharmacologic blockade of the voltage and calcium clocks could provide insight into its mechanism. Spontaneous beat to beat (A-A) intervals were obtained from monophasic action potential recordings of perfused canine right atrial preparations before and during perfusion with acetylcholine (2-5 µM). The calcium clock was blocked with ryanodine (2-3 µM). The membrane clock was blocked with diltiazem hydrochloride (ICa,L blocker; 0.25 µM) and ZD7288 (If blocker; 3 µM). Hyperpolarization was hindered by blockade of IK,Ado/IK,Ach with tertiapin Q (100 nM) before and during acetylcholine perfusion. Acetylcholine resulted in beat clusters similar to those seen in sinus arrhythmia of the dog. Beat clusters were consistent with intermittent 2:1 and 3:1 sinoatrial conduction block. Tertiapin Q abolished this patterning suggesting a role of IK,Ado/IK,ACh in the mechanism of these acetylcholine-induced beat-to-beat patterns.
Assuntos
Acetilcolina/administração & dosagem , Arritmia Sinusal/veterinária , Doenças do Cão/fisiopatologia , Átrios do Coração/efeitos dos fármacos , Bloqueio Cardíaco/veterinária , Nó Sinoatrial/fisiopatologia , Animais , Arritmia Sinusal/fisiopatologia , Cães , Eletrocardiografia/veterinária , Átrios do Coração/fisiopatologia , Bloqueio Cardíaco/induzido quimicamente , Bloqueio Cardíaco/fisiopatologia , Frequência Cardíaca/efeitos dos fármacosRESUMO
We propose a solution to a long-standing problem: how to terminate multiple vortices in the heart, when the locations of their cores and their critical time windows are unknown. We scan the phases of all pinned vortices in parallel with electric field pulses (E-pulses). We specify a condition on pacing parameters that guarantees termination of one vortex. For more than one vortex with significantly different frequencies, the success of scanning depends on chance, and all vortices are terminated with a success rate of less than one. We found that a similar mechanism terminates also a free (not pinned) vortex. A series of about 500 experiments with termination of ventricular fibrillation by E-pulses in pig isolated hearts is evidence that pinned vortices, hidden from direct observation, are significant in fibrillation. These results form a physical basis needed for the creation of new effective low energy defibrillation methods based on the termination of vortices underlying fibrillation.
RESUMO
BACKGROUND: Although urate impaired the endothelial function, its underlying mechanism remains unknown. We hypothesized that urate impaired nitric oxide (NO) production in human umbilical vein endothelial cells (HUVECs) via activation of uric acid transporters (UATs). PURPOSE AND METHOD: In the present study, we studied effects of urate on NO production and eNOS protein expression in HUVEC cells in the presence and absence of urate lowering agents using molecular biological and biochemical assays. RESULTS: HUVECs expressed the 4 kinds of UATs, URATv1, ABCG2, MRP4 and MCT9. Exposure to urate at 7 mg/dl for 24 h significantly reduced production of NO. Pretreatment with benzbromarone, losartan or irbesartan normalized NO production. The same exposure resulted in dephosphorylation of endothelial NO synthase (eNOS) in HUVECs. Again pretreatment with benzbromarone, losartan or irbesartan abolished this effect. CONCLUSION: Urate reduced NO production by impaired phosphorylation of eNOS in HUVEC via activation of UATs, which could be normalized by urate lowering agents.
Assuntos
Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Óxido Nítrico Sintase Tipo III/metabolismo , Óxido Nítrico/metabolismo , Ácido Úrico/farmacologia , Uricosúricos/farmacologia , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/antagonistas & inibidores , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Benzobromarona/farmacologia , Compostos de Bifenilo/farmacologia , Células Cultivadas , Proteínas Facilitadoras de Transporte de Glucose/antagonistas & inibidores , Proteínas Facilitadoras de Transporte de Glucose/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Irbesartana , Losartan/farmacologia , Transportadores de Ácidos Monocarboxílicos/antagonistas & inibidores , Transportadores de Ácidos Monocarboxílicos/metabolismo , Proteínas Associadas à Resistência a Múltiplos Medicamentos/antagonistas & inibidores , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/metabolismo , Fosforilação , Tetrazóis/farmacologiaRESUMO
OBJECTIVES: The purpose of this study was to evaluate the MRI characteristics of venous thrombus over set time thresholds with histopathological correlation in a porcine model. METHODS: Inferior vena cava thrombi were induced in 12 pigs. MRI was performed in three pigs 2 h, 1 day, 3 days and 2 weeks after thrombus induction. RESULTS: The MRI characteristics were analysed in correlation with histopathological findings. The thrombi after 2 hours, which consisted of red blood cells (RBCs), showed isointensity on T(1 )weighted images (T(1)WIs) and hyperintensity on both T(2 )weighted images (T(2)WIs) and diffusion-weighted images (DWIs). The mean apparent diffusion coefficient (ADC) value was 1.93 × 10(-3) mm(2) s(-1). The thrombi after Day 1, which consisted of RBCs and migrating neutrophils at the periphery, showed isointensity on T(1)WIs, slight hyperintensity on T(2)WIs and hypointensity on DWIs. The mean ADC value was 1.62 × 10(-3) mm(2) s(-1) [corrected]. The thrombi after Day 3, which consisted of RBCs and peripheral inflammatory cells including macrophages, showed isointensity with peripheral hyperintense regions on T(1)WIs and hypointensity on both T(2)WIs and DWIs. The mean ADC value was 1.67 × 10(-3) mm(2) s(-1). After 2 weeks, the thrombi, which revealed RBC lysis surrounded by granulation tissues, showed isointensity on T(1)WIs and hyperintensity on T(2)WIs and DWIs. The mean ADC value was 2.48 × 10(-3) mm(2) s(-1). CONCLUSION: The temporal MRI characteristics seemed to be related to chemical and physical changes in RBC and organisation of granulation tissues. Free radicals generated by macrophages might also be related to some extent.
Assuntos
Imageamento por Ressonância Magnética , Trombose Venosa/patologia , Animais , Imagem de Difusão por Ressonância Magnética , Eritrócitos/patologia , Feminino , Tecido de Granulação/patologia , Suínos , Fatores de Tempo , Veia Cava Inferior/patologiaRESUMO
K201 has previously been shown to reduce diastolic contractions in vivo during ß-adrenergic stimulation and elevated extracellular calcium concentration ([Ca(2+)](o)). The present study characterised the effect of K201 on electrically stimulated and spontaneous diastolic sarcoplasmic reticulum (SR)-mediated Ca(2+) release and contractile events in isolated rat cardiomyocytes during ß-adrenergic stimulation and elevated [Ca(2+)](o). Parallel experiments using confocal microscopy examined spontaneous diastolic Ca(2+) release events at an enhanced spatiotemporal resolution. 1.0 µmol/L K201 in the presence of 150 nmol/L isoproterenol (ISO) and 4.75 mmol/L [Ca(2+)](o) significantly decreased the amplitude of diastolic contractions to ~16% of control levels. The stimulated free Ca(2+) transient amplitude was significantly reduced, but stimulated cell shortening was not significantly altered. When intracellular buffering was taken into account, K201 led to an increase in action potential-induced SR Ca(2+) release. Myofilament sensitivity to Ca(2+) was not changed by K201. Confocal microscopy revealed diastolic events composed of multiple Ca(2+) waves (2-3) originating at various points along the cardiomyocyte length during each diastolic period. 1.0 µmol/L K201 significantly reduced the (a) frequency of diastolic events and (b) initiation points/diastolic interval in the remaining diastolic events to 61% and 71% of control levels respectively. 1.0 µmol/L K201 can reduce the probability of spontaneous diastolic Ca(2+) release and their associated contractions which may limit the propensity for the contractile dysfunction observed in vivo.
Assuntos
Cálcio/metabolismo , Ventrículos do Coração/efeitos dos fármacos , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Tiazepinas/farmacologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Animais , Diástole/efeitos dos fármacos , Diástole/fisiologia , Ventrículos do Coração/metabolismo , Masculino , Microscopia Confocal , Contração Miocárdica/fisiologia , Miócitos Cardíacos/metabolismo , Técnicas de Patch-Clamp , Ratos , Ratos Wistar , Retículo Sarcoplasmático/efeitos dos fármacos , Retículo Sarcoplasmático/metabolismoRESUMO
BACKGROUND: Lidocaine is most frequently used to treat ventricular arrhythmias. However, lidocaine may have an antiarrhythmic effect for certain supraventricular arrhythmias. HYPOTHESIS: We hypothesized that lidocaine would be effective in converting experimentally induced atrial fibrillation (AF) to sinus rhythm and that a decrease in the dominant frequency (DF) and an increase in the organization as judged by the spectral entropy (SE) would occur over the course of the conversion. ANIMALS: Seven German Shepherd (GS) Dogs. METHODS: Dogs were anesthetized with fentanyl and pentobarbital. AF was induced with standard pacing protocols while left and right atrial monophasic action potentials (MAP) were recorded. The power spectra from the MAP recordings were analyzed to determine DF and SE during treatment with boluses of 2 mg/kg lidocaine. RESULTS: Lidocaine converted AF to sinus rhythm in all dogs and all episodes (n = 19). Conversion time was 27-87 seconds. After atropine, sustained AF was not induced; however, 5 episodes of atrial tachycardia resulted, and 3 were converted with lidocaine. Frequency domain analysis of 12 conversion sequences showed that left and right DF of the MAP signals decreased from the time of injection to conversion to sinus rhythm (P < .001). Mean SE indicated a gradient between the left and right atria (P = .003) that did not change during conversion. CONCLUSIONS AND CLINICAL IMPORTANCE: Vagally associated AF in GS dogs is terminated with lidocaine. Lidocaine is likely an effective treatment in clinical dogs with vagally associated AF.
Assuntos
Antiarrítmicos/uso terapêutico , Fibrilação Atrial/veterinária , Doenças do Cão/tratamento farmacológico , Lidocaína/uso terapêutico , Nervo Vago/fisiologia , Animais , Fibrilação Atrial/tratamento farmacológico , Fibrilação Atrial/genética , Doenças do Cão/genética , Cães , Predisposição Genética para DoençaRESUMO
BACKGROUND: The thalamic cavernous angioma (CA) represents a neurosurgical challenge because of the critical neurologic functions of the thalamus and its surrounding structures and of their deep location inside the brain. Although the natural history of the thalamic CA remains undefined, several studies suggest the poor outcome of those patients especially if the symptomatic thalamic CA is treated conservatively. We describe the advantage of the paraculminar supracerebellar approach to the lesions in the brainstem. OBJECTIVE: We studied the usefulness and the safety of the paraculminar supracerebellar infratentorial transtentorial approach for the patients with thalamic CA. METHODS: One hundred and ninety two consecutive patients with CA were treated at the Department of Neurosurgery in the Zurich University Hospital between 1993 and 2003. Among these patients, we analyzed six patients (four female, mean age 43) with thalamic CA who underwent surgical removal with the paraculminar supracerebellar transtentorial approach. We retrospectively reviewed their medical charts, the neuroradiological images, and the operative notes/video records. RESULTS: Four patients of the six presented with thalamic hemorrhage. CA existed in the left thalamus in four patients and in the right in two. Preoperative symptoms included sensorimotor disturbance (three cases), double vision (three cases), Parinaud syndrome (one case), and thalamic pain (one case). All patients had the thalamic CA completely removed without any postoperative deterioration. CONCLUSIONS: This study suggests that for the removal of thalamic cavernous angioma the paraculminar supracerebellar infratentorial transtentorial approach provides the spacious surgical field with reduced risks of damaging and sacrificing surrounding vascular and neuronal system. This approach could proffer one of the best and safest surgical routes for the radical removal of thalamic cavernous angioma.
Assuntos
Neoplasias Encefálicas/cirurgia , Hemangioma Cavernoso/cirurgia , Procedimentos Neurocirúrgicos/métodos , Tálamo/cirurgia , Adulto , Neoplasias Encefálicas/patologia , Seio Cavernoso/patologia , Seio Cavernoso/cirurgia , Feminino , Hemangioma Cavernoso/patologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Neuronavegação/métodos , Estudos Retrospectivos , Tálamo/patologia , Tomografia Computadorizada por Raios X/métodos , Resultado do TratamentoRESUMO
OBJECTIVES: The drug K201 (JTV-519) increases inotropy and suppresses arrhythmias in failing hearts, but the effects of K201 on normal hearts is unknown. METHODS: The effect of K201 on excitation-contraction (E-C) coupling in normal myocardium was studied by using voltage-clamp and intracellular Ca(2+) measurements in intact cells. Sarcoplasmic reticulum (SR) function was assessed using permeabilised cardiomyocytes. RESULTS: Acute application of <1 micromol/L K201 had no significant effect on E-C coupling. K201 at 1 micromol/L decreased Ca(2+) transient amplitude (to 83+/-7%) without affecting I(Ca,L) or the SR Ca(2+) content. At 3 micromol/L K201 caused a larger reduction of Ca(2+) transient amplitude (to 60+/-7%) with accompanying reductions in I(Ca,L) amplitude (to 66+/-8%) and SR Ca(2+) content (74+/-9%). Spontaneous SR Ca(2+) release during diastole was induced by increasing intracellular [Ca(2+)]. At 1 micromol/L K201 reduced the frequency of spontaneous Ca(2+) release. The effect of K201 on SR-mediated Ca(2+) waves and Ca(2+) sparks was examined in beta-escin-permeabilised cardiomyocytes by confocal microscopy. K201 (1 micromol/L) reduced the frequency and velocity of SR Ca(2+) waves despite no change in SR Ca(2+) content. At 3 micromol/L K201 completely abolished Ca(2+) waves and reduced the SR Ca(2+) content (to approximately 73%). K201 at 1 micromol/L reduced Ca(2+) spark amplitude and frequency. Assays specific to SR Ca(2+)-ATPase and RyR2 activity indicated that K201 inhibited both SR Ca(2+) uptake and release. CONCLUSIONS: K201 modifies E-C coupling in normal cardiomyocytes. A dual inhibitory action on SERCA and RyR2 explains the ability of K201 to suppress spontaneous diastolic Ca(2+) release during Ca(2+) overload without significantly affecting Ca(2+) transient amplitude.
Assuntos
Cálcio/metabolismo , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Tiazepinas/farmacologia , Animais , Cafeína/farmacologia , Ventrículos do Coração/metabolismo , Humanos , Coelhos , Canal de Liberação de Cálcio do Receptor de Rianodina/fisiologia , Retículo Sarcoplasmático/metabolismo , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Proteínas de Ligação a Tacrolimo/metabolismoRESUMO
Gap junctions are intercellular channels that mediate the cytoplasmic exchange of small hydrophilic molecules and are formed by a family of integral membrane proteins called connexins (Cxs). Cx43 is expressed predominantly in astrocytes, while Cx36 is expressed in neurons. In this study, we show alteration of Cx43 and Cx36 in the hippocampus after traumatic brain injury in rats. Adult male Sprague-Dawley rats were subjected to lateral fluid percussion injury of moderate severity. Brain coronal sections were used for immunohistochemistry with Cx43 and Cx36 antibodies. Cx43 immunoreactivity was increased in reactive astrocytes in the damaged hippocampus 24 hours after injury, and persisted for 72 hours. On the other hand, Cx36 immunoreactivity increased in CA3 neurons 1 hour after injury, and decreased later. These results indicate that gap junctions might participate in the pathophysiological process after traumatic brain injury.
Assuntos
Lesões Encefálicas/metabolismo , Conexina 43/metabolismo , Conexinas/metabolismo , Junções Comunicantes/metabolismo , Traumatismos Cranianos Fechados/metabolismo , Hipocampo/metabolismo , Adaptação Fisiológica , Animais , Lesões Encefálicas/complicações , Traumatismos Cranianos Fechados/complicações , Masculino , Ratos , Ratos Sprague-Dawley , Distribuição Tecidual , Proteína delta-2 de Junções ComunicantesRESUMO
BACKGROUND: Aneurysms located on the distal posterior inferior cerebellar artery (PICA) are rare, and their underlying clinical features and surgical management are poorly understood. We report our series of 16 patients with 18 distal PICA aneurysms. METHOD: All patients with distal PICA aneurysms were treated between March 1996 and August 2004. We excluded all PICA aneurysms that involved the vertebral artery. Patients were analysed in the light of their clinical profiles, radiological studies, intraoperative findings and outcomes. All patients underwent non-enhanced and contrast enhanced CT scans followed by 4-vessel cerebral angiography on admission. The hemorrhagic patterns on initial CT scans were assessed using the Fisher Grading Score. The outcomes were documented using the Glasgow Outcome Scale at time of discharge and at three or twelve months follow-up. FINDINGS: The series included 6 men and 10 women. Massive intraventricular haemorrhage was found in 13 patients with proven CT subarachnoid haemorrhage, one patient revealed SAH without intraventricular components, one presented with only intraventricular blood in the occipital horns and 3 aneurysms were found incidentally without presence of blood. Fourteen aneurysms were saccular and four were fusiform. Nine cases were associated with another cerebrovascular lesion. A lateral transcondylar or a median suboccipital approach was used to secure the aneurysms in 15 patients, either by direct clipping (14 lesions) or vessel sacrifice (3 lesions). One aneurysm was treated by an endovascular approach. At long-term follow up, an excellent or good outcome was achieved in 75% of cases. One patient died due to pre-existing cardiopulmonary complications. CONCLUSIONS: Most of our cases of ruptured distal PICA aneurysms presented with haematocephalus. These were frequently associated with another vascular abnormality and 22% were fusiform or multilobulated. These specific features require special management strategies entailing an appropriate surgical approach to the aneurysm, clipping method, haematoma removal, ventricular drainage and when suitable choice of endovascular interventions.
Assuntos
Cerebelo/irrigação sanguínea , Artérias Cerebrais/fisiopatologia , Artérias Cerebrais/cirurgia , Aneurisma Intracraniano/fisiopatologia , Aneurisma Intracraniano/cirurgia , Procedimentos Neurocirúrgicos/métodos , Procedimentos Cirúrgicos Vasculares/métodos , Adulto , Idoso , Doenças Cerebelares/patologia , Doenças Cerebelares/fisiopatologia , Doenças Cerebelares/cirurgia , Cerebelo/patologia , Angiografia Cerebral , Ventrículos Cerebrais/patologia , Ventrículos Cerebrais/fisiopatologia , Feminino , Humanos , Aneurisma Intracraniano/diagnóstico , Síndrome Medular Lateral/diagnóstico , Síndrome Medular Lateral/fisiopatologia , Síndrome Medular Lateral/cirurgia , Masculino , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos/estatística & dados numéricos , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Hemorragia Subaracnóidea/diagnóstico , Hemorragia Subaracnóidea/fisiopatologia , Instrumentos Cirúrgicos/estatística & dados numéricos , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Procedimentos Cirúrgicos Vasculares/estatística & dados numéricos , Artéria Vertebral/diagnóstico por imagem , Artéria Vertebral/patologia , Artéria Vertebral/cirurgiaRESUMO
The detailed processes involved in spiral wave breakup, believed to be one major mechanism by which tachycardia evolves into fibrillation, are still poorly understood. This has rendered difficult the proper design of an efficient and practical control stimulus protocol to eliminate such events. In order to gain new insights into the underlying electrophysiological and dynamical mechanisms of breakup, we applied linear perturbation theory to a steadily rotating spiral wave in two spatial dimensions. The tissue was composed of cells modeled using the Fenton-Karma equations whose parameters were chosen to emphasize alternans as a primary mechanism for breakup. Along with one meandering mode, not just one but several unstable alternans modes were found with differing growth rates, frequencies, and spatial structures. As the conductance of the fast inward current was increased, the instability of the modes increased, consistent with increased meandering and propensity for spiral breakup in simulations. We also explored a promising new approach, based on the theory, for the design of an energy efficient electrical stimulus protocol to control spiral wave breakup. The novelty lies in addressing the problem directly at the ion channel level and taking advantage of the inherent two dimensional nature of the rotating wave. With the help of the eigenmode method, we were able to calculate the exact timing and amplitude of the stimulus, and locate it optimally to maximize efficiency. The analysis led to a special-case example that demonstrated that a single, properly timed stimulus can have a global effect, suppressing all growing alternans modes over the entire tissue, thus inhibiting spiral wave breakup.
Assuntos
Cardioversão Elétrica/métodos , Sistema de Condução Cardíaco/fisiopatologia , Frequência Cardíaca , Ventrículos do Coração/fisiopatologia , Canais Iônicos , Modelos Cardiovasculares , Células Musculares , Fibrilação Ventricular/fisiopatologia , Animais , Simulação por Computador , Humanos , Fibrilação Ventricular/terapiaRESUMO
We describe the changes in extracellular superoxide dismutase (EC-SOD) following cerebral ischemia in mice. Mice were subjected to transient forebrain ischemia and reperfusion. The measurements of EC-SOD using ELISA showed increased brain EC-SOD after 24 h of reperfusion. The immunohistochemical examination showed that EC-SOD immunoreactivity in cortical and striatal capillary wall was conspicuous after 3 h. EC-SOD immunoreactivity was also noted in cortical neurons after 24 h. Northern blot analysis showed an increased EC-SOD mRNA expression in the brain after 24 h. In situ hybridization study demonstrated no mRNA expression of EC-SOD following ischemia and reperfusion in the capillary wall. These findings suggest that serum EC-SOD might accumulate on brain endothelial cells, while cortical neurons produce EC-SOD themselves after cerebral ischemia with reperfusion.
Assuntos
Isquemia Encefálica/enzimologia , Espaço Extracelular/enzimologia , Superóxido Dismutase/metabolismo , Animais , Northern Blotting , Ensaio de Imunoadsorção Enzimática , Imuno-Histoquímica , Hibridização In Situ , Camundongos , Camundongos Endogâmicos C57BL , RNA Mensageiro/metabolismo , Superóxido Dismutase/genéticaRESUMO
Astrocytes perform a variety of functions in the adult central nervous system (CNS). Recent evidence suggests the robust upregulation of glial fibrillary acidic protein (GFAP) after CNS insult. However, little is known about the role of GFAP in the hippocampal degeneration after brain injury. We herein compared the GFAP knockout (KO) and wild type (WT) mice on the histological and behavioral outcome in response to cerebral trauma or kainic acid (KA)-induced seizure. Although all KO mice showed hippocampal CA3 neuronal degeneration. WT mice did not show any neuronal degeneration in CA3 subfield at 72 hrs after trauma. Thereafter, KO mice showed a higher susceptibility to KA-induced seizures and an increased number of pyknotic CA3 neurons 72 hrs after KA administration. These results indicate that GFAP plays a crucial role in the hippocampal neurodegeneration after CNS insult.
Assuntos
Lesões Encefálicas/metabolismo , Lesões Encefálicas/patologia , Proteína Glial Fibrilar Ácida/metabolismo , Hipocampo/patologia , Degeneração Neural/patologia , Convulsões/metabolismo , Convulsões/patologia , Animais , Sobrevivência Celular , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Ácido Caínico , Camundongos , Camundongos Knockout , Neurônios , Convulsões/induzido quimicamente , Ferimentos não Penetrantes/metabolismo , Ferimentos não Penetrantes/patologiaRESUMO
Mitogenic stimulation of the Mitogen-activated protein kinase (MAPK) pathway modulates the activity of many transcriptional factors leading to biological responses. Of these, three MAPK cascades are well characterized as extracellular signal-regulated protein kinase (ERK), c-Jun NH(2)-terminal kinase (JNK), and p38 pathways. The aim of this study was to investigate the topographic distribution and the role of activated MAPK pathways after fluid percussion injury (FPI) in rats. In the present results, FPI significantly induced ERK- and JNK-phosphorylation, but not p38-phosphorylation in the cortex and hippocampus at the injury site. The immunoreactivity for phospho-ERK was localized in the superficial neuronal layers, dentate hilar neurons, and the damaged CA3 neurons after 30 mins of FPI. Double immunostaining showed that phospho-ERK was prominent in astrocytes 6 hrs after TBI. The current results suggest that MAPK pathways are involved in signal transduction after FPI.
Assuntos
Lesões Encefálicas/enzimologia , Encéfalo/enzimologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Animais , Córtex Cerebral/enzimologia , Hipocampo/enzimologia , Imuno-Histoquímica , Proteínas Quinases JNK Ativadas por Mitógeno , Masculino , Fosforilação , Ratos , Ratos Sprague-Dawley , Distribuição Tecidual , Ferimentos não Penetrantes/enzimologia , Proteínas Quinases p38 Ativadas por MitógenoRESUMO
Central salt wasting syndrome may be caused by pathological increases in serum natriuretic peptides after subarachnoid hemorrhage (SAH). However, it is unclear as to why the serum concentration of atrial natriuretic peptide (ANP) or brain natriuretic peptide (BNP) increases in the subacute phase of SAH. The present study was designed to assess the correlation between focal brain edema and serum concentration of ANP or BNP in patients with SAH. Focal brain edema was found in 8 SAH-patients and peaked between days 4 and 7 of SAH. The mean serum ANP and BNP levels in patients with focal brain edema were significantly higher than those in patients without focal brain edema between days 4 and 14 of SAH. These results suggest that focal brain edema might correlate with increased levels of ANP and BNP in the subacute phase of SAH.
Assuntos
Fator Natriurético Atrial/sangue , Edema Encefálico/sangue , Edema Encefálico/etiologia , Peptídeo Natriurético Encefálico/sangue , Hemorragia Subaracnóidea/sangue , Hemorragia Subaracnóidea/complicações , Edema Encefálico/diagnóstico por imagem , Humanos , Estudos Retrospectivos , Hemorragia Subaracnóidea/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Vasopressinas/sangueRESUMO
Vascular endothelial growth factor (VEGF) is known to be a mediator of angiogenesis and vascular permeability. A cystic component and hemorrhage are often found in pituitary adenomas. In the present study we assess the VEGF expression based on immunohistochemical examinations in 48 pituitary adenomas. All the adenomas showed some VEGF immunoreactivity mainly in the cytoplasm of tumor cells. Of the 48 adenoma-cases, 16 cases had a strong VEGF immunoreactivity, 26 cases had a moderate one, and 6 cases had a weak one. On the MR images, a cystic component was found in 16 cases (33.3%), and a hemorrhage was found in 18 cases (37.5%). The VEGF immunoreactivity had a significant relationship with the cystic component but neither the hemorrhage, size, recurrence, or HE classification. These findings suggest that VEGF might play a potential role in the pathogenesis of cystic formation in pituitary adenomas.
Assuntos
Adenoma/metabolismo , Neoplasias Hipofisárias/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Adenoma/diagnóstico , Adenoma/patologia , Adolescente , Adulto , Idoso , Cistos/metabolismo , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neoplasias Hipofisárias/diagnóstico , Neoplasias Hipofisárias/patologia , Estudos RetrospectivosRESUMO
Extracellular signal-regulated kinase (ERK) pathways play a crucial role in cell growth and long-lasting neuronal plasticity. Several studies have shown that phosphorylated-ERK (p-ERK) significantly increases after kainic acid (KA) administration. However, little or no information is available about the spatial distribution of p-ERK after KA-induced seizures. We herein show that KA-induced seizures significantly increase p-ERK in both neurons and astrocytes in rat brain using Western blots and immunohistochemistry. A strong immunoreactivity for p-ERK was induced in the dentate hilar neurons and CA3 neurons 30 mins and 6 hrs after KA injection. In addition, immunoreactivity for p-ERK was seen in astrocytes 6 hrs after KA injection. 72 hrs after KA injection, all pyramidal neurons had died. These findings suggest that the ERK pathway participates in the KA-induced neurotoxicity in the rat hippocampus.