Functions of G protein-coupled receptor kinase interacting protein 1 in human neuronal (NT2N) cells

OBJECT: Promotion of the repair and regeneration of damaged adult neurons is a major goal of neurological science. In this study, the effects of G protein-coupled receptor kinase interacting protein 1 (GIT1) overexpression in human neuron cells were tested in human neuronal cells by using an adenoviral vector. METHODS: A recombinant GIT1 and enhanced green fluorescent protein (EGFP) adenoviral vector (AdGIT1) was created by using a standard viral construction procedure. Human neuronal (NT2N) cells, which had been derived from an NT2 human teratocarcinoma cell line, were used in this experiment. Immunocytochemical methods were applied to identify NT2N cells with neural features and to probe the relationship among signaling proteins. Several biological activities were assessed, including neural spine formation, cell migration, and the levels of expression of growth-associated protein-43 (GAP-43) and active Cdc42. The number of cells with spine formation and the number of migrated cells were significantly higher in the AdGIT1-treated group of NT2N cells than in untreated (control) NT2N cells or in AdEGFP-treated NT2N cells. The levels of GAP-43 and active Cdc42 expression were significantly higher in the AdGITl-treated group than that in the other two cell groups. CONCLUSIONS: The results of this study demonstrate that GIT1 overexpression has the potential to promote neural spine formation and cell migration in human neuronal cells. At the same time, the increased level of GAP-43 in GIT1-overexpressed cells indicates that GIT1 may have the potential to improve growth and regeneration of damaged axons. The GIT1-beta-PIX-Cdc42-PAK pathway may play an important role in neuronal outgrowth.     

Brain tumors with hemorrhage.

Various types of brain tumors may cause hemorrhage. The purpose of the study was to examine the clinical relevance of tumor hemorrhage and the hemorrhagic mechanism from the pathologic viewpoint. We retrospectively reviewed 761 consecutive brain tumor cases according to clinical, operative, and pathologic records. Pituitary adenomas and recurrent tumors were excluded. Twenty-seven patients (17 men and 10 women, mean age, 50 years) with brain tumor hemorrhage were identified, resulting in an incidence of 3.5%. In 632 cases of primary brain tumors, there were 15 cases with hemorrhage, resulting in an incidence of 2.4%. There were 12 cases of brain tumor hemorrhage in 129 patients with metastatic tumors, for an incidence of 9.3% Among hemorrhagic cases, 63.0% of patients presented with acute onset of clinical deterioration. In 72.7% of gliomas with hemorrhage, hematoma appeared within the tumor, and 75% of metastatic brain tumors with hemorrhage were intracerebral hemorrhages around the borders of the tumors. The highest hemorrhage rate for primary brain tumors occurred in pilocytic astrocytomas, while the highest hemorrhage rates in secondary tumors occurred in metastatic thyroid papillary carcinomas and hepatocellular carcinomas. In our pathology study, increasing intratumor vascularization with dilated, thin-walled vessels and tumor necrosis were the most important mechanisms of hemorrhage.     

Atorvastatin preconditioning attenuates the production of endothelin-1 and prevents experimental vasospasm in rats

Objective  

Induced endothelin-1 (ET-1) production and decreased nitric oxide synthase (NOS) bioavailability have been found in aneurysmal subarachnoid hemorrhage (SAH). Atorvastatin is recognized to have pleiotropic effects including increasing NOS bioavailability as well as reducing inflammation and oxidative damage other than reducing dyslipidemia. This study is of interest to examine the effect of atorvastatin on ET-1/endothelial nitric oxide synthase (eNOS) in experimental SAH.     

6-Mercaptopurine attenuates adhesive molecules in experimental vasospasm

Objective  

Adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin, are important inflammatory mediators which are elevated in the serum of patients following aneurysmal subarachnoid hemorrhage (SAH). The authors previously found that 6-mercaptopurine (6-mp) was effective in preventing and reversing arterial narrowing in a rodent SAH model. The present study was to examine whether levels of adhesion molecules were altered after treatment with 6-mp in this animal model.     

Expression of Rac3 in human brain tumors.

Rac3 may play an important role in tumor growth but little is known about its expression and mutation in human tumor tissues. We examined the expression of Rac3 using RT-PCR and mutation of the Rac3 gene by DNA sequencing. Overexpression of the Rac3 gene occurred in 19% (5/26) of brain tumors; 3 of 9 (33%) meningiomas, 1 of 11 (9%) astrocytomas and 1 of 6 (17%) pituitary adenomas. Two of the 3 meningiomas with Rac3 overexpression were recurrent meningiomas. The only astrocytoma with Rac3 overexpression was a glioblastoma multiforme. Mutation of the Rac3 gene occurred in 63% (12/19) of brain tumours; 4 of 7 (57.1%) meningiomas, 4 of 5 (80%) pituitary adenomas and 4 of 7 (57.1%) astrocytomas. Except in one astrocytoma, the other four tumors with Rac3 overexpression (3 meningiomas and one pituitary adenoma) did not have Rac3 mutations. Our data is the first report of the frequency of Rac3 overexpression and mutation in human brain tumors. Overexpression may be associated with aggressive tumor behavior. The relationship between Rac3 expression and mutation requires further investigation.     

Preoperative and postoperative seizures in patients with astrocytic tumours: analysis of incidence and influencing factors.

To evaluate the incidence and influencing factors related to preoperative and postoperative seizures, a retrospective analysis was performed in 190 patients with astrocytic tumours. Preoperative seizures occurred in 50 (26%) patients and 27 (54%) of the m had recurrent seizures. Late-onset seizures developed after craniotomy in 11 (8%) of 140 patients. Seizures at presentation were significantly correlated with age at diagnosis (P=0.0204) and pathological grade of tumour (P=0.0040). The patients aged less than 40 years had a high risk of seizures at presentation (odds ratio=3.076, P=0.0134). Postoperative seizures were significantly associated with the presence of preoperative seizures (P<0.0001), type or duration of preoperative seizures (P<0.0001, P<0.0001, respectively) and serum level of anticonvulsant drug (P=0.0068). However, only the presence of preoperative seizures had a potential for prediction of postoperative seizures when evaluated by logistic regression model (odds ratio=20.859, P=0.0001). Fifty-nine percent of patients with recurrent seizures and 64% of patients with late-onset seizures had seizures which occurred within 6 months after craniotomy. Despite therapeutic anticonvulsant levels, most postoperative seizures were associated with tumour recurrence or haemorrhage. Postoperative seizures commonly occurred relatively soon after craniotomy and prophylactic anticonvulsants should be given. In patients with postoperative seizures, particularly in the presence of therapeutic anticonvulsant level, brain computed tomography should be performed to exclude tumour recurrence or haemorrhage.     

The outcome of percutaneous computed tomography-guided chemical lumbar sympathectomy for patients with causalgia after lumbar discectomy

BACKGROUND: Coldness, numbness, or causalgia usually affects the lower limbs in patients after back surgeries. The treatment of causalgia is still the source of continuing debate. We treated patients presenting with causalgia secondary to LD with CT-guided CLS and determined the therapeutic outcome at long-term follow-up. METHODS: From January 2002 to December 2002, a total of 15 patients (16 limbs) with causalgia after LD underwent the percutaneous CT-guided CLS. There were 7 male patients and 8 female patients, with an average age of 49.1 years. A total of 14 patients underwent unilateral procedures, and 1 patient underwent staged bilateral procedures. We followed up our patients for at least 24 months (24-36 months). RESULTS: There were 13 patients (14 limbs) diagnosed as Drucker stage I and 2 patients as stage II. There were 88% (14 limbs) that had an early satisfactory outcome after CLS and 75% (12 limbs) that had a late satisfactory outcome (more than 24 months after CLS). Stage I patients had more satisfying early and late outcome than stage II patients (P= .014 and P= .039, respectively). Female patients were more likely to have satisfactory late outcome than male patients (P= .034). There was no operative mortality. A patient had a complication of genitofemoral neuralgia, which had recovered in a month. CONCLUSIONS: We concluded that the percutaneous CT-guided CLS is an easy, safe, and reproducible technique, and it carries long-term benefit to patients with pain after LD presenting with causalgia, especially for patients with Drucker stage I and female patients.     

Activation of BKCa channels via cyclic AMP- and cyclic GMP-dependent protein kinases by eugenosedin-A in rat basilar artery myocytes

BACKGROUND AND PURPOSE: The study investigated whether eugenosedin-A, a 5-hydroxytryptamine and alpha/beta adrenoceptor antagonist, enhanced delayed-rectifier potassium (K(DR))- or large-conductance Ca(2+)-activated potassium (BK(Ca))-channel activity in basilar artery myocytes through cyclic AMP/GMP-dependent and -independent protein kinases. EXPERIMENTAL APPROACH: Cerebral smooth muscle cells (SMCs) were enzymatically dissociated from rat basilar arteries. Conventional whole cell, perforated and inside-out patch-clamp electrophysiology was used to monitor K(+)- and Ca(2+)-channel activities. KEY RESULTS: Eugenosedin-A (1 microM) did not affect the K(DR) current but dramatically augmented BK(Ca) channel activity in a concentration-dependent manner. Increased BK(Ca) current was abolished by charybdotoxin (ChTX, 0.1 microM) or iberiotoxin (IbTX, 0.1 microM), but not affected by a small-conductance K(Ca) blocker (apamin, 100 microM). BK(Ca) current activation by eugenosedin-A was significantly inhibited by an adenylate cyclase inhibitor (SQ 22536, 10 microM), a soluble guanylate cyclase inhibitor (ODQ, 10 microM), competitive antagonists of cAMP and cGMP (Rp-cAMP, 100 microM and Rp-cGMP, 100 microM), and cAMP- and cGMP-dependent protein kinase inhibitors (KT5720, 0.3 microM and KT5823, 0.3 microM). Eugenosedin-A reversed the inhibition of BK(Ca) current induced by the protein kinase C activator, phorbol myristyl acetate (PMA, 0.1 microM). Eugenosedin-A also prevented BK(Ca) current inhibition induced by adding PMA, KT5720 and KT5823. Moreover, eugenosedin-A reduced the amplitude of voltage-dependent L-type Ca(2+) current (I(Ca,L)), but without modifying the voltage-dependence of the current. CONCLUSIONS AND IMPLICATIONS: Eugenosedin-A enhanced BK(Ca) currents by stimulating the activity of cyclic nucleotide-dependent protein kinases. Physiologically, this activation would result in the closure of voltage-dependent calcium channels and thereby relax cerebral SMCs.