Ebselen inhibits p38 mitogen-activated protein kinase-mediated endothelial cell death by hydrogen peroxide

Ebselen (2-phenyl-1, 2-benzisoselenazol-3[2H]-one) is a seleno-organic compound exhibiting both glutathione peroxidase and antioxidant activity. Although it has been reported that ebselen is effective against hydrogen peroxide (H(2)O(2))-induced cell death in several cell types, its effect on endothelial cell damage has not yet been elucidated. In the present study, we examined the effect of ebselen on H(2)O(2)-induced human umbilical vein endothelial cells (HUVECs) death, and its intracellular mechanism. Our findings showed that pretreatment of HUVECs with ebselen resulted in a significant recovery from H(2)O(2)-induced cell death in a concentration-dependent manner. In addition to the inhibition of lactate dehydrogenase (LDH) leakage, ebselen inhibited H(2)O(2)-induced cytochrome c release and caspase-3 activation and the resultant apoptosis in HUVECs. Moreover, it was observed that H(2)O(2) significantly stimulated activation of mitogen-activated protein (MAP) kinases, i.e., p38 MAP kinase, c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK1/2). Ebselen inhibited H(2)O(2)-induced p38 MAP kinase, but not JNK or ERK1/2 activation. Furthermore, SB203580 (4-[4-fluorophenyl]-2-[4-methylsulfinylphenyl]-5-[4-pyridyl]-1H-imidazole), a specific p38 MAP kinase inhibitor, inhibited H(2)O(2)-induced p38 MAP kinase phosphorylation, cytochrome c release, caspase-3 activation, as well as cell death in HUVECs. These findings suggest that ebselen attenuates H(2)O(2)-induced endothelial cell death through the inhibition of signaling pathways mediated by p38 MAP kinase, caspase-3, and cytochrome c release. Thus, inhibition of p38 MAP kinase by ebselen may imply its usefulness for prevention and/or treatment of endothelial cell dysfunction, which was suggested to be the first step in the development of atherosclerosis.     

Src and Cas are essentially but differentially involved in angiotensin II-stimulated migration of vascular smooth muscle cells via extracellular signal-regulated kinase 1/2 and c-Jun NH2-terminal kinase activation

Angiotensin II (Ang II) plays an important role in several cardiovascular diseases associated with vascular smooth muscle cell (VSMC) growth and migration. Src activity is known to be required for the migration of a number of cell types. p130Cas was reported to be essential for cell migration and actin filament reorganization. Mitogen-activated protein (MAP) kinases were also reported to be critical regulatory factors for growth and migration of VSMC. However, precise intracellular mechanisms involving c-Src, p130Cas, and MAP kinases in Ang II-stimulated migration of VSMC have not been well elucidated. Here we demonstrated that Ang II rapidly and significantly stimulated tyrosine phosphorylation of Src and Cas and their association in rat aortic smooth muscle cells (RASMC). Ang II-stimulated tyrosine phosphorylation of Src and Cas and activation of ERK1/2 and JNK, but not p38, were potently inhibited by Src family tyrosine kinase inhibitors, herbimycin A (HA) and PP2. Ang II-stimulated Src and Cas association, tyrosine phosphorylation of Cas, and activation of ERK1/2 and JNK were suppressed in kinase-inactive Src (KI Src)-overexpressed RASMC. Ang II-stimulated JNK activation but not ERK1/2 activation was blocked in substrate domain-deleted Cas (DeltaSD Cas)-overexpressed RASMC. In addition, HA, PP2, ERK1/2 inhibitor, 2'-amino-3'-methoxyflavone (PD98059) and JNK inhibitor, and anthra[1,9-cd]pyrazol-6(2H)-one (SP600125) significantly inhibited Ang II-stimulated migration of RASMC. Ang II-induced colocalization of Src and Cas and migration were inhibited in both KI Src- and DeltaSD Cas-overexpressed RASMC. These findings suggest that Src and Cas are essentially but differentially involved in Ang II-stimulated migration of VSMC through the activation of ERK1/2 and JNK.     

Isolated intracranial Rosai-Dorfman disease mimicking meningioma

Sinus histiocytosis with massive lymphadenopathy (SHML), also known as Rosai-Dorfman disease (RDD), is an idiopathic histiocytic proliferation affecting lymph nodes. It is typically characterized by painless cervical lymphadenopathy, fever and weight loss. Although extranodal involvement has been reported in diverse sites, intracranial presentation, particularly in the absence of nodal disease is uncommon. To the best of our knowledge, 48 patients with intracranial masses have been reported previously. A 31-year-old man was admitted to our clinic with a 4-month history of progressive headache. His medical history was unremarkable except for occasional fever. There were not any neurological deficit and weight loss. No lymphadenopathy (particularly bilateral cervical) and extranodal involvement in diverse sites were revealed by physical and radiological examinations. Routine hematological and biochemical studies were normal except for mild leukocytosis and elevated erythrocyte sedimentation rate. The patient underwent magnetic resonance imaging (MRI) testing that revealed an enhancing mass in the left temporal lobe. Preoperative diagnosis was meningioma. The patient underwent a left frontotemporal craniotomy with complete resection of the mass. Histopathology was compatible with RDD. Extranodal RDD is rarely found intracranially. Prognosis is benign especially in the absence of nodal disease. It is clinically and radiologically difficult to distinguish from meningioma, and histological examination is essential for a definitive diagnosis.     

Vascular wall damage in rats induced by methidathion and ameliorating effect of vitamins E and C

We examined the effect of subacute methidathion (MD) administration on vascular wall damage and evaluated the ameliorating effects of combination of vitamins E and C against MD toxicity. The experimental groups were: rats treated with corn oil (control group), rats treated with 5 mg/kg MD (MD), and rats treated with 5 mg/kg body weight MD plus vitamin E and vitamin C (MD+Vit). The groups were given MD by gavage on 5 days a week for 4 weeks at a daily dose 5 mg/kg (MD and MD+Vit) using corn oil as the vehicle. Vitamins E and C were injected at doses of 50 mg/kg intramuscularly and 20 mg/kg intraperitoneally, respectively, after the treatment with MD in the MD+Vit group. The levels of malondialdehyde (MDA) were determined in the aortic tissue. Histopathological examination was examined in the thoracic aortic tissue. MDA levels were higher in the MD group than the control group and lower in the MD+Vit group than MD group. MD administration led to irregulation, prominent breaks, and fragmentation of the elastic fibers but decrease in the irregulation and fragmantation of the elastic fibers with the combination of vitamins E and C in MD-treated rats. In conclusion, it is likely that subacute MD administration caused vascular wall damage, and that treatment with a combination of vitamins E and C after the administration of MD can reduce vascular wall damage caused by MD.     

Characteristics of acute adult poisoning cases admitted to a university hospital in Istanbul

BACKGROUND: The aim of this retrospective study was to analyse the characteristics of acute adult poisoning cases admitted to a university hospital in Istanbul, Turkey. PATIENTS AND METHODS: All cases admitted to the Emergency Unit of the Istanbul University Cerrahpa?a Medical Faculty Hospital, between January 2001 and December 2001, were included in this study. We analysed the clinical charts for aetiological and demographical characteristics of the acutely poisoned patients. RESULTS: There were 284 poisoning cases (207 females and 77 males) among 11834 patients admitted to the Emergency Unit. This was 2.4% of all emergency admissions. The female-to-male ratio was 3:1. The mean age was 27+/-12 years (age range 15-87) and the majority of the patients (73.94%) were below the age of 30 years. The median age was 24 years. Medicinal drugs were the major cause (69.37%) of the cases, followed by inhalation of gases (14.44%), alcohol (5.99%), alcohol together with illicit drugs (4.23%), food (3.17%), corrosives (1.76%) and pesticides (1.06%). The route of administration was as follows: 84.51% orally, 14.44% by inhalation and 1.06% by intravenous injection. Seventy-one per cent of acute poisonings were self-inflicted and 88% occurred at home. The most frequently involved medicinal drugs were antidepressants and analgesics. In 32.04% of cases, there was more than one medicinal drug responsible for the poisoning. The seasonal distribution in poisoning patients suggested a peak in summer (31.7% of presentations) and winter (30.9%) and lower numbers in spring (22.9%) and autumn (14.5%). The follow-up period of the patients were 1-12 hours for 42 cases (15%), 13-24 hours for 134 cases (47%) and more than 24 hours for 108 cases (38%). Two of the 284 cases with acute poisonings were fatal. This was a university hospital-based study, so these results may not be representative of the general population. Despite this drawback, these data still provide important information about the characteristics of poisoning in the largest city of the country. cn     

Revascularization of myocardial scar tissue following prostaglandin E1-therapy in patients with ischemic heart disease

Prostaglandin E1 (PGE-1) treatment has proved to stimulate angiogenesis in vital non-infarcted myocardium of patients with ischemic cardiomyopathy (ICMP). We investigated infarcted myocardial tissue for a possible angiogenic response to PGE-1. Neovascularization was investigated in infarcted areas of 12 hearts explanted from patients with ICMP who had been treated with PGE-1 before heart transplantation (HTX). In transmural sections containing myocardial scar tissue, CD34 and VEGF were immunohistochemically quantified to estimate capillary density and the extent of angiogenesis. To investigate a possible effect of PGE-1 on collagen turnover, the collagen content was determined in myocardial scar tissue by assessing the intensity of the area positively stained with sirius red. PGE-1-treated patients had significantly more CD34- and VEGF-positive cells in infarcted areas, and showed a significant reduction in collagen content as compared with the non-PGE-1 group (CD34: 120.3 +/- 6.1 vs. 47.7 +/- 6.1 capillary profiles/mm2; VEGF: 52.8 +/- 5.6 vs. 24.0 +/- 4.8 capillary profiles/mm2, and collagen content: 2.18 +/- 0.4 eU vs. 3.59 +/- 0.38 eU). Our data demonstrate that PGE-1 stimulates angiogenesis by upregulating VEGF expression, and reduces fibrosis in cardiac scar tissue of ischemic origin. The induction of therapeutic angiogenesis in vital and at sites of putative dead myocardial scar tissue, along with the hemodynamic improvement in patients with severe ICMP, might explain the favorable clinical outcome in PGE-1-treated patients before HTX.     

The effect of intracerebroventricular dopamine administration on the respiratory response to hypoxia

Acute hypoxia produces an increase in ventilation. When the hypoxia is sustained, the initial increase in ventilation is followed a decrease in ventilation. The precise mechanism of this decline in ventilation during sustained hypoxia is unknown. Recent studies hypothesized that the accumulation of dopamine in the central nervous system might have a major role in production of hypoxic respiratory depression. The purpose of this study was to examine whether dopamine has an effect on occurance of central ventilatory depression which is seen in acute hypoxia in peripheral chemoreceptors denervated animals. The experiment were conducted in rabbits anesthetized with Na-pentobarbital (25 mg x kg(-1) i.v.). For intracerebroventricular (i.c.v.) injections of dopamine (1 microg) in each animal, canula was placed in left lateral cerebral ventricle by stereotaxic method. Respiratory frequency (f x min(-1)), tidal volume (V(T)) ventilation minute volume (V(E)) and systemic arterial blood pressure (BP) were recorded during air and 3 minutes hypoxic gas mixture (8%O2-92%N2) breathing. I.c.v. administration of dopamine during normoxia decreased V(T), f, V(E) and BP, significantly. When rabbits were injected with an i.c.v. dopamine on hypoxic gas mixture breathing in control animals, there was depression of hypoxic ventilatory responses. After i.c.v. administration of dopamine antagonists haloperidol (0.1 mg) and domperidone (0.07 mg) in chemodenervated rabbits, the significant increases in V(T), V(E) and BP were observed. On the breathing of hypoxic gas mixture of chemodenervated and i.c.v. dopamine antagonists administrated rabbits, hypoxic depression was completely abolished. These results of this study show that accumulation of dopamine in the brain seems to reduce the response of the central control mechanisms to chemoreceptor impulses during normoxia and hypoxia. In conclusion present study suggests important role played by central dopaminergic pathways in the occurence of acute hypoxic ventilatory depression.     

Reversal of iron deficiency anemia-induced peripheral neuropathy by iron treatment in children with iron deficiency anemia

The effects of iron deficiency anemia (IDA) on nerve conduction and efficiency of iron therapy were investigated by peripheral nerve-electrophysiological measurements. Eighteen children (10 boys, eight girls; mean age 31 +/- 1.3 months) with IDA and 12 healthy children (six boys, six girls; mean age 29 +/- 1.3 months) were enrolled into the study. Nerve conduction velocity was measured in the median and posterior tibial nerve. After nerve conduction values were determined in the patients and controls, 6 mg/kg/24 h ferrous sulphate was given orally to the patients for 3 months and nerve conduction velocity tests were performed again. Median/motor and sensory nerve conduction velocity and tibial/motor nerve distal-amplitute values of children with IDA were lower than for the control group (p < 0.05, p < 0.01 and p < 0.001 respectively). With iron supplementation these values increased to the normal levels and even higher than control levels for some parameters. In correlation studies between whole blood parameters and nerve conduction velocity results, there was a correlation between median/sensory nerve conduction velocity values and serum iron levels. Additionally there was a correlation between some nerve conduction velocity values and age. In conclusion, the evidence from this preliminary study suggests that peripheral neuropathy may develop in children with IDA. Peripheral neuropathy symptoms in these patients may be improved by iron therapy.     

New anticoagulants in the treatment of stroke： future promise

Recent evidence is leading to the replacement of vitamin K antagonists, the efficacy of which in preventing stroke in patients with atrial fibrillation （AF） is well established, with better tolerated and more manageable new anticoagulant drugs, with a lower risk of intracranial bleeding, no clear interactions with food, fewer interactions with medications, and no need for frequent laboratory monitoring and dose adjustments. Among new anticoagulants, dabigatran etexilate is a direct, competitive inhibitor of thrombin. It was evaluated for patients with AF in the RE-LY trial, showing lower rates of stroke and systemic embolism at a dose of 150 mg twice daily with similar rates of major hemorrhage compared with warfarin; and non-inferiority compared with warfarin for the prevention of stroke and systemic embolism at a dose of 110 mg twice daily, with lower rates of major bleeding. Beside dabigatran, oral factor X a inhibitors are also emerging for the prevention of thromboembolic events in AF. Despite the obvious advantages of these new oral anticoagulants over vitamin K antagonists, further information is still needed on how to prioritize the patients deriving the greatest benefit from these novel agents on the basis of patient characteristics or drug pharmacokinetics. There is also a need for assessing their long-term efficacy and safety over decades in the real-world setting.