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1.
Asian J Surg ; 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38760222

RESUMO

OBJECTIVES: Intraoperative frozen section (FS) analysis is pivotal in guiding surgical interventions for early-stage lung adenocarcinoma. However, the challenge arises when distinguishing between Minimally Invasive Adenocarcinoma (MIA) and Invasive Adenocarcinoma (IAC) poses diagnostic difficulties. This study investigates the prognosis and clinicopathological characteristics of patients encountering this diagnostic challenge. METHODS: We conducted a retrospective analysis of 7082 intraoperative FSs from early-stage lung adenocarcinoma cases. The cases with pulmonary nodules within 3 cm and diagnosed as indeterminate FSs were included. We analyzed baseline data, computed tomography (CT) findings, and pathological characteristics. Prognostic data were obtained from patients with confirmed IAC diagnoses through final pathological examination. RESULTS: Out of 7082 FSs, 551 cases presented challenges in distinguishing between MIA and IAC. Upon final pathological examination, 233 cases were identified as IAC, while 314 were classified as MIA. The median invasive pathological size in the IAC group was larger than that in the MIA group (0.6 cm vs 0.3 cm). 131 cases (56.2 %) with IAC underwent lobectomy, while 102 cases (43.8 %) underwent sub-lobar resection. Among the MIA cases, 220 cases (69.8 %) underwent sub-lobar resection, while 95 cases (30.2 %) underwent lobectomy. No recurrence and disease specific death was observed during the follow-up period, regardless of surgical strategy. CONCLUSIONS: Indeterminate intraoperative FSs, posing diagnostic challenges in distinguishing between MIA and IAC. Sub-lobar resection presented the same long term survival benefit compared with the lobectomy for indeterminate lung adenocarcinoma within 3 cm during intraoperative FSs.

2.
Pestic Biochem Physiol ; 195: 105580, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37666605

RESUMO

Red swamp crayfish, Procambarus clarkii, is a globally invasive species, which has caused great damage to biodiversity, agriculture, and fishing. Therefore, the development of effective management methods, such as pheromone control, is necessary for biological control and biodiversity protection. However, the components of P. clarkii sex pheromones have not yet been explored, and the chemosensory mechanism of the P. clarkii antennae after stimulation by sex pheromone also remains unknown. In this study, we isolated and identified the candidate bioactive component of the female P. clarkii sex pheromone using ultrafiltration centrifugation, semi-preparative liquid phase separation and omics technologies and conducted bioassays to determine its attraction ability. Meanwhile, RNA-Seq technology was used to analyze the potential chemosensory mechanism of antennae. Our results indicated that the male P. clarkii were uniaxially attracted to the female crude conditioned water (FCW), medium fraction (MF, isolated by ultrafiltration centrifugation), and preparative fragment 6 of females (PFF6, isolated by semi-preparative liquid phase separation). Metabolomic analysis revealed the presence of 18 differential metabolites between the PFF6 and PFM6 samples, among which 15 were significantly upregulated in the PFF6 sample. Bioassay test also showed that mestranol, especially at concentrations of 10-5-10-2 mol∙l-1, could significantly attract P. clarkii males; therefore, mestranol was identified as the candidate sex pheromone component of P. clarkii females. Furthermore, RNA-Seq results showed that most differentially expressed genes (DEGs) enriched in lipid metabolism and signal transduction pathways were up-regulated in P. clarkii males. In addition, high expressions of Ca2+-binding protein and ion transporting ATPases may enhance the sensitivity of the antennae of P. clarkii males towards sex pheromones. Our study provides data on P. clarkii sex pheromone composition and reveals the molecular mechanism of sex pheromone response in P. clarkii. Moreover, our study provides a referable method for the isolation of candidate bioactive molecules from the P. clarkii sex pheromone.


Assuntos
Atrativos Sexuais , Feminino , Masculino , Animais , Atrativos Sexuais/farmacologia , Astacoidea , Mestranol , Feromônios , Adenosina Trifosfatases
3.
Sci Transl Med ; 13(591)2021 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-33910977

RESUMO

Acute lung injury (ALI) causes high mortality and lacks any pharmacological intervention. Here, we found that pazopanib ameliorated ALI manifestations and reduced mortality in mouse ALI models and reduced edema in human lung transplantation recipients. Pazopanib inhibits mitogen-activated protein kinase kinase kinase 2 (MAP3K2)- and MAP3K3-mediated phosphorylation of NADPH oxidase 2 subunit p47phox at Ser208 to increase reactive oxygen species (ROS) formation in myeloid cells. Genetic inactivation of MAP3K2 and MAP3K3 in myeloid cells or hematopoietic mutation of p47phox Ser208 to alanine attenuated ALI manifestations and abrogates anti-ALI effects of pazopanib. This myeloid MAP3K2/MAP3K3-p47phox pathway acted via paracrine H2O2 to enhance pulmonary vasculature integrity and promote lung epithelial cell survival and proliferation, leading to increased pulmonary barrier function and resistance to ALI. Thus, pazopanib has the potential to be effective for treating ALI.


Assuntos
Lesão Pulmonar Aguda , Indazóis/farmacologia , MAP Quinase Quinase Quinase 2/antagonistas & inibidores , MAP Quinase Quinase Quinase 3/antagonistas & inibidores , Pirimidinas/farmacologia , Sulfonamidas/farmacologia , Lesão Pulmonar Aguda/tratamento farmacológico , Animais , Humanos , Peróxido de Hidrogênio , Camundongos , NADPH Oxidases/metabolismo , Fosforilação , Espécies Reativas de Oxigênio
4.
J Clin Invest ; 131(10)2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-33793424

RESUMO

BACKGROUNDCurrent clinical management of patients with pulmonary nodules involves either repeated low-dose CT (LDCT)/CT scans or invasive procedures, yet causes significant patient misclassification. An accurate noninvasive test is needed to identify malignant nodules and reduce unnecessary invasive tests.METHODWe developed a diagnostic model based on targeted DNA methylation sequencing of 389 pulmonary nodule patients' plasma samples and then validation in 140 plasma samples independently. We tested the model in different stages and subtypes of pulmonary nodules.RESULTSA 100-feature model was developed and validated for pulmonary nodule diagnosis; the model achieved a receiver operating characteristic curve-AUC (ROC-AUC) of 0.843 on 140 independent validation samples, with an accuracy of 0.800. The performance was well maintained in (a) a 6 to 20 mm size subgroup (n = 100), with a sensitivity of 1.000 and adjusted negative predictive value (NPV) of 1.000 at 10% prevalence; (b) stage I malignancy (n = 90), with a sensitivity of 0.971; (c) different nodule types: solid nodules (n = 78) with a sensitivity of 1.000 and adjusted NPV of 1.000, part-solid nodules (n = 75) with a sensitivity of 0.947 and adjusted NPV of 0.983, and ground-glass nodules (n = 67) with a sensitivity of 0.964 and adjusted NPV of 0.989 at 10% prevalence. This methylation test, called PulmoSeek, outperformed PET-CT and 2 clinical prediction models (Mayo Clinic and Veterans Affairs) in discriminating malignant pulmonary nodules from benign ones.CONCLUSIONThis study suggests that the blood-based DNA methylation model may provide a better test for classifying pulmonary nodules, which could help facilitate the accurate diagnosis of early stage lung cancer from pulmonary nodule patients and guide clinical decisions.FUNDINGThe National Key Research and Development Program of China; Science and Technology Planning Project of Guangdong Province; The National Natural Science Foundation of China National.


Assuntos
Metilação de DNA , DNA de Neoplasias/metabolismo , Neoplasias Pulmonares , Nódulos Pulmonares Múltiplos , Tomografia Computadorizada por Raios X , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/metabolismo , Masculino , Pessoa de Meia-Idade , Nódulos Pulmonares Múltiplos/diagnóstico , Nódulos Pulmonares Múltiplos/diagnóstico por imagem , Nódulos Pulmonares Múltiplos/metabolismo , Estudos Retrospectivos
5.
Surg Innov ; 25(2): 121-127, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29357784

RESUMO

OBJECTIVES: The investigation was aimed to evaluate the safety and efficacy of glasses-free 3-dimensional (3D) video-assisted thoracoscopic surgery (VATS) versus 2D VATS for radical resection of non-small cell lung cancer (NSCLC). METHODS: We reviewed the clinical data of patients with pathologically proven NSCLC who underwent glasses-free 3D (the 3D group) and 2D VATS radical lobectomy (the 2D group) with systematic lymph node dissection. The outcomes of this study included operative characteristics and safety of 2D and 3D VATS, and duration of lymphadenectomy of right stations 2 and 4. RESULTS: A total of 190 patients were eligible for the study. The 2D group consisted of 108 patients while the 3D group included 82 patients. The 2 groups were comparable in demographic and baseline variables ( P > .05). The median number of resected lymph nodes was 19 in both groups ( P = .583). The median length of hospital stay was comparable between the 2 groups (2D, 7 days vs 3D, 8 days; P = .167). No operative mortality was reported in either group. Complications developed in 21 (19.4%) patients in the 2D group and 14 (17.1%) in the 3D group ( P = .710). A subgroup analysis of patients who underwent right station 2 and 4 lymphadenectomy showed that the mean time for right station 2 and 4 lymph node dissection was significantly shorter in the 3D group than in the 2D group (3D, 430.9 ± 237.2 vs 2D, 648.6 ± 364.1 seconds; P < .001). CONCLUSIONS: Glasses-free 3D VATS and 2D VATS are comparable in operative characteristics and safety profile for radical resection of NSCLC. Glasses-free 3D visualization facilitates more rapid right-sided mediastinal lymphadenectomy.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/cirurgia , Neoplasias Pulmonares/cirurgia , Cirurgia Torácica Vídeoassistida , Idoso , Feminino , Humanos , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , Estudos Retrospectivos , Cirurgia Torácica Vídeoassistida/efeitos adversos , Cirurgia Torácica Vídeoassistida/métodos , Cirurgia Torácica Vídeoassistida/estatística & dados numéricos , Resultado do Tratamento
6.
J Vis Surg ; 3: 31, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29078594

RESUMO

The push for minimally invasive techniques had led to the development of many surgical tools and the innovation and completion of ever more complex operations. To achieve faster postoperative recovery of patients, we have been dedicated to the development of surgical skills that have allowed us to successfully complete many procedures under video-assisted thoracoscopic surgery (VATS) that are complex even with open approach. Specifically, sleeve, trachea, and carina resections and reconstructions using either general or spontaneous respiration anesthesia (SRA) techniques. Our long term high volume thoracic experience has equipped us with a talented multidisciplinary team with the ability to confidently and safely perform many types of complicated VATS procedures.

7.
Behav Brain Res ; 314: 226-33, 2016 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-27491589

RESUMO

Tobacco smoking is the leading cause of preventable death in the United States. Nicotine is the principal psychoactive ingredient in tobacco that causes addiction. The structures governing nicotine addiction, including those underlying withdrawal, are still being explored. Nicotine withdrawal is characterized by negative affective and cognitive symptoms that enhance relapse susceptibility, and suppressed dopaminergic transmission from ventral tegmental area (VTA) to target structures underlies behavioral symptoms of nicotine withdrawal. Agonist and partial agonist therapies help 1 in 4 treatment-seeking smokers at one-year post-cessation, and new targets are needed to more effectively aid smokers attempting to quit. Hypothalamic orexin/hypocretin neurons send excitatory projections to dopamine (DA)-producing neurons of VTA and modulate mesoaccumbal DA release. The effects of nicotinic receptor blockade, which is commonly used to precipitate withdrawal, on orexin neurons remain poorly investigated and present an attractive target for intervention. The present study sought to investigate the effects of nicotinic receptor blockade on hypothalamic orexin neurons using mecamylamine to precipitate withdrawal in rats. Separate groups of rats were treated with either chronic nicotine or saline for 7-days at which point effects of mecamylamine or saline on somatic signs and anxiety-like behavior were assessed. Finally, tissue from rats was harvested for immunofluorescent analysis of Fos within orexin neurons. Results demonstrate that nicotinic receptor blockade leads to reduced orexin cell activity, as indicated by lowered Fos-immunoreactivity, and suggest that this underlying cellular activity may be associated with symptoms of nicotine withdrawal as effects were most prominently observed in rats given chronic nicotine. We conclude from this study that orexin transmission becomes suppressed in rats upon nicotinic receptor blockade, and that behavioral symptoms associated with nicotine withdrawal may be aided by intervention upon orexinergic transmission.


Assuntos
Neurônios/efeitos dos fármacos , Antagonistas Nicotínicos/farmacologia , Orexinas/metabolismo , Receptores Nicotínicos/efeitos dos fármacos , Animais , Dopamina/farmacologia , Imuno-Histoquímica/métodos , Masculino , Neurônios/metabolismo , Nicotina/farmacologia , Proteínas Oncogênicas v-fos/metabolismo , Ratos Sprague-Dawley , Área Tegmentar Ventral/efeitos dos fármacos , Área Tegmentar Ventral/metabolismo
8.
J Thorac Dis ; 8(3): 608-11, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27076959

RESUMO

The role of video-assisted thoracoscopic surgery (VATS) radical resection in the treatment of lung cancer has widely recognized. Studies have demonstrated that the thoracoscopic radical treatment of lung cancer can achieve similar long-term survival as that of conventional open surgeries; meanwhile, it can be applied for bronchial sleeve resection that is more challenging for most thoracic surgeons. Bronchial sleeve pneumonectomy can avoid total pneumonectomy when removing tumors, and therefore it can lower the surgery-associated mortality and improve the long-term survival by maximizing the preservation of lung function. Thus, it has become a standard procedure for central-type lung cancer. We have completed a glasses-free three-dimensional (3D) complete thoracoscopic surgery in a patient with central-type lung cancer in his right lung. During the surgery, we found the tumor had invaded the right pulmonary trunk, right main bronchus, and lateral wall of superior vena cava.

9.
J Thorac Dis ; 8(3): 612-6, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27076960

RESUMO

Lung cancer invading the superior vena cava (SVC) is a locally advanced condition, for which poor prognosis is expected with conservative treatment alone. Surgical resection of the lesion can rapidly relieve the symptoms and significantly improve survival for some patients. Replacement, repair and partial resection of SVC via thoracotomy were generally accepted and used in the past. As the rapid development of minimally invasive techniques and devices, partial resection and repair of SVC are feasible via video-assisted thoracic surgery (VATS). However, few studies have reported the VATS surgical techniques. In this study, we reported the crucial techniques of partial resection of SVC via VATS.

10.
J Thorac Dis ; 8(3): 617-27, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27076961

RESUMO

Lung cancer invading pulmonary trunk is a locally advanced condition, which may indicate poor prognosis. Surgical resection of the lesion can significantly improve survival for some patients. Lobectomy/Pneumonectomy with pulmonary arterioplasty via thoracotomy were generally accepted and used in the past. As the rapid development of minimally invasive techniques and devices, pulmonary arterioplasty is feasible via video-assisted thoracic surgery (VATS). However, few studies have reported the VATS surgical techniques. In this study, we reported the techniques of pulmonary arterioplasty via VATS.

11.
J Thorac Dis ; 7(10): 1798-805, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26623103

RESUMO

BACKGROUND: Three-dimensional (3D) vision systems are now available for thoracic surgery. It is unclear whether 3D video-assisted thoracic surgery (VATS) is superior to 2D VATS systems. This study aimed to compare the operative and perioperative data between 2D and 3D VATS lobectomy (VTL) and to identify the actual role of 3D VTL in thoracic surgery. METHODS: A two-institutional comparative study was conducted from November 2013 to November 2014 at Liaoning Cancer Hospital & Institute and the First Affiliated Hospital of Guangzhou Medical University, China, of 300 patients with resectable non-small cell lung cancer (NSCLC). Patients were assigned to receive either the 3D VATS (n=150) or 2D VATS (n=150) lobectomy. The operative and perioperative data between 2D VATS and 3D VATS were compared. RESULTS: Although there was no significant difference between the two groups regarding the incidence of each single complication, a significantly less operative time was found in the 3D VATS group (145 min) than in the 2D VATS group (176 min) (P=0.006). Postoperative mortality rates in 3D VATS and 2D VATS groups were both 0%.No significant difference was found between groups for estimated blood loss (P=0.893), chest drainage tube placement time (P=0.397), length of hospital stay (P=0.199), number of lymph nodes resected (P=0.397), postoperative complications (P=0.882) and cost of care (P=0.913). CONCLUSIONS: Early results of this study demonstrate that the 3D VATS lobectomy procedure can be performed with less operative time. 3D VATS and 2D VATS lobectomy are both safe procedures in first-line surgical treatment of NSCLC.

12.
Physiol Behav ; 92(1-2): 54-9, 2007 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-17617428

RESUMO

In the present paper we describe our on-going project investigating the functional roles of the N-methyl-D-aspartate (NMDA) receptor subunit NR3A. We find that NR3A mRNA is abundant both in embryonic and adult human brain, in contrast to the almost non-existing expression in adult rodent brain. Human NR3A (hNR3A) protein expression is particularly abundant in the cerebral cortex, as shown by western blot using NR3A-specific antibodies. Distribution of hNR3A in adult human brain shows a similar pattern as NR3A in post-natal rodent brain. We have previously reported that NR3A contains a glycine binding site, with similar affinity as the glycine binding site of NR1 subunits. This suggests that NR3A may replace one of the two NR1 subunits in native NMDA receptors. Cloning of hNR3A showed a human-specific polyproline-sequence in the intracellular C-terminus, that may bind to SH3-domains. We hypothesized that the significant differences in expression in the adult human and rodent brain could be due to an atypical interaction of hNR3A with the SH3 domain of the synaptic scaffolding protein PSD-95, that binds to NR2 subunits through its PDZ domains. However, using a number of different protein interaction assays, binding of PSD-95 to hNR3A could no be demonstrated either in vitro or in vivo. To identify intracellular signaling pathways for NR3A-containing NMDA receptors, we screened for proteins interacting with hNR3A and identified three proteins: plectin, CARP-1 and GPS2. The possible physiological roles of these interactions are discussed.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Receptores de N-Metil-D-Aspartato/fisiologia , Sinapses/fisiologia , Animais , Córtex Cerebral/citologia , Córtex Cerebral/fisiologia , Espinhas Dendríticas/fisiologia , Humanos , Camundongos , Subunidades Proteicas , Ratos , Receptores de N-Metil-D-Aspartato/genética
13.
World J Gastroenterol ; 10(18): 2637-42, 2004 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-15309710

RESUMO

AIM: To evaluate the safety of Curcuma aromatica oil gelatin microspheres (CAO-GMS) infused via hepatic artery against primary liver cancer. METHODS: The safety of CAO-GMS was evaluated in view of its acute toxicity in rats, long-term toxicity in Beagle dogs and general pharmacology in rats and mongrel dogs. RESULTS: The 50% lethal dose (LD50) of CAO-GMS infused via the hepatic artery was 17.19 mg/kg, and the serum biochemical indices of dying rats after the administration changed markedly while those of survived rats did not. Subsequent pathological examination of the tissues from the dead rats indicated improper embolism. Similar edema and small necrotic foci in the hepatic lobule were found in the hepatic tissue of rats receiving 10 and 5 mg/kg CAO-GMS and GMS 60 d after the last administration, while not in the rats of the blank control group, indicating that microspheres infused via the hepatic artery may induce irreversible liver damage dose-dependently. General pharmacological study showed that the activities (posture and gait), respiration frequency, blood pressure or heart rate of the dogs were not affected by CAO-GMS, nor were salivation, tremor or pupil changes of the rats observed or their balancing ability compromised, suggesting CAO-GMS infused via the hepatic artery did not significantly affect the nervous, respiratory and cardiovascular systems. CONCLUSION: CAO-GMS embolization administered via the hepatic artery is safe but undesired embolization induced by vascular variation should be given due attention in its clinical application. Individualized embolization dosage and super-selective catheterization technique are recommended to avoid undesired embolism and reduce complications.


Assuntos
Curcuma , Medicamentos de Ervas Chinesas/toxicidade , Neoplasias Hepáticas/tratamento farmacológico , Óleos de Plantas/toxicidade , Doença Aguda , Animais , Pressão Sanguínea/efeitos dos fármacos , Quimioembolização Terapêutica , Cães , Feminino , Gelatina/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Artéria Hepática , Injeções Intra-Arteriais , Fígado/efeitos dos fármacos , Fígado/patologia , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/patologia , Masculino , Microesferas , Sistema Nervoso/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Respiração/efeitos dos fármacos
14.
J Neurochem ; 81(4): 696-707, 2002 May.
Artigo em Inglês | MEDLINE | ID: mdl-12065629

RESUMO

We investigated the ability of GM1 to induce phosphorylation of the tyrosine kinase receptor for neurotrophins, Trk, in rat brain, and activation of possible down-stream signaling cascades. GM1 increased phosphorylated Trk (pTrk) in slices of striatum, hippocampus and frontal cortex in a concentration- and time-dependent manner, and enhanced the activity of Trk kinase resulting in receptor autophosphorylation. The ability of GM1 to induce pTrk was shared by other gangliosides, and was blocked by the selective Trk kinase inhibitors K252a and AG879. GM1 induced phosphorylation of TrkA > TrkC > TrkB in a region-specific distribution. Adding GM1 to brain slices activated extracellular-regulated protein kinases (Erks) in all three brain regions studied. In striatum, GM1 elicited activation of Erk2 > Erk1 in a time-and concentration-dependent manner. The GM1 effect on Erk2 was mimicked by other gangliosides, and was blocked by the Trk kinase inhibitors K252a and AG879. Pertussis toxin, as well as Src protein tyrosine kinase and protein kinase C inhibitors, did not prevent the GM1-induced activation of Erk2, apparently excluding the participation of Gi and Gq/11 protein-coupled receptors. Intracerebroventricular administration of GM1 induced a transient phosphorylation of TrkA and Erk1/2 in the striatum and hippocampus complementing the in situ studies. These observations support a role for GM1 in modulating Trk and Erk phosphorylation and activity in brain.


Assuntos
Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Gangliosídeo G(M1)/farmacologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Receptor trkA/metabolismo , Animais , Relação Dose-Resposta a Droga , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Gangliosídeo G(M1)/administração & dosagem , Proteínas de Ligação ao GTP/metabolismo , Gangliosídeos/farmacologia , Técnicas In Vitro , Injeções Intraventriculares , Masculino , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Fator de Crescimento Neural/farmacologia , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-raf/antagonistas & inibidores , Ratos , Ratos Sprague-Dawley , Receptor trkA/antagonistas & inibidores , Receptor trkB/metabolismo , Receptor trkC/metabolismo , Receptores de Superfície Celular/metabolismo , Fatores de Tempo
15.
J Neurotrauma ; 19(2): 257-66, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11893026

RESUMO

Glutamate toxicity is a viable hypothesis to explain the expanding tissue degeneration occurring after traumatic or ischemic spinal cord injury. One important component in this process is the acute, excessive release of glutamate. In the current communication, the glycolytic inhibitor iodoacetate was used to induce metabolic inhibition in spinal cord slices and thereby provide an in vitro model to study the mechanisms of pathological glutamate release in the spinal cord. The evoked glutamate release was not Ca2+-dependent. Exclusion of NaCl reduced the evoked release of endogenous glutamate by 56%, while excluding Na+ increased release. Glutamate release was also reduced by the PLA2 inhibitors indomethacin (40%), arachidonyltrifluoromethyl ketone (45%) and 4-bromophenacyl bromide (36%). Blocking reverse glutamate transport by preincubation with 1 mM dihydrokainic acid reduced evoked release by 41%. However, when the dihydrokainic acid and arachidonyltrifluoromethyl ketone treatments were combined, no additive effect of the two substances was seen. These findings suggest that glutamate is released by three mechanisms from the energy compromised spinal cord: (1) in response to cellular swelling, most likely by the regulatory volume decrease, (2) by PLA2-mediated breakdown of the cell membrane and diffusion of glutamate down its concentration gradient, and (3) through reversal of the glutamate transporter.


Assuntos
Adenosina/análogos & derivados , Metabolismo Energético/efeitos dos fármacos , Ácido Glutâmico/metabolismo , Medula Espinal/metabolismo , Adenosina/farmacologia , Animais , Ácidos Araquidônicos/farmacologia , Baclofeno/farmacologia , Cálcio/metabolismo , Inibidores Enzimáticos/farmacologia , Agonistas GABAérgicos/farmacologia , Técnicas In Vitro , Indazóis/farmacologia , Iodoacetatos/farmacologia , Masculino , Neurotoxinas/metabolismo , Fosfolipases/metabolismo , Ratos , Ratos Sprague-Dawley , Medula Espinal/efeitos dos fármacos
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