Ghrelin and obestatin are a single gene products and are a multiple functional peptides that regu... more Ghrelin and obestatin are a single gene products and are a multiple functional peptides that regulates energy homeostasis, and food intake. In the present work, we studied the secretion of ghrelin and its co-secreted peptide obestatin in 44 patients with ischemic heart disease with that of 27 healthy matched controls. Here we first conducted using an immunohistochemistry assay to screen whether human salivary glands have any obestatin immunoreactivity. Then, serum and saliva obestatin and acylated ghrelin levels were determined by using Radioimmunoassay. Our immunohistochemical analysis demonstrated that obestatin was localized in the striated and excretory duct of human salivary gland. We also report for the first time that obestatin, like ghrelin, is present in human salivary gland and saliva. No evidence of the role of obestatin or ghrelin saliva levels in the context of ischemic heart disease was found. Salivary ghrelin and obestatin levels are correlated in controls with the blood levels. Determination of salivary values could represent a non-invasive alternative to serum ones that can be useful in clinical practice. [BMB reports 2008; 41(1): 55-61]
The role of diffusion-weighted magnetic resonance imaging (MRI) for differentiation between vario... more The role of diffusion-weighted magnetic resonance imaging (MRI) for differentiation between various causes of cervical lymphadenopathy was evaluated. In a prospective study, 31 untreated patients (22 males and nine females, aged 5–70 years) with 87 cervical lymph nodes underwent diffusion-weighted MRI before performance of neck dissection (n=14), surgical biopsy (n=9) or core biopsy (n=8). Diffusion-weighted MR images were acquired with a b factor of 0 and 1,000 s/mm2 using single-shot echo-planar sequence. Apparent diffusion coefficient (ADC) maps were reconstructed for all patients. The signal intensity of the lymph nodes was assessed on images obtained at b=0 or 1,000 s/mm2 and from the ADC maps. The ADC value of lymph nodes was also calculated. On the ADC map, malignant nodes showed either low (n=52) or mixed (n=20) signal intensity and benign nodes revealed high (n=13) or low (n=2) signal intensity. The mean ADC value of metastatic (1.09±0.11×10−3 mm2/s) and lymphomatous (0.97±0.27×10−3 mm2/s) lymph nodes was significantly lower than that of benign (1.64±0.16×10−3 mm2/s) cervical lymph nodes (P<0.04). When an ADC value of 1.38×10−3 mm2/s was used as a threshold value for differentiating malignant from benign lymph nodes, the best results were obtained with an accuracy of 96%, sensitivity of 98%, specificity of 88%, positive predictive value of 98.5% and negative predictive value of 83.7%. The smallest detected lymph node was 0.9 cm. In conclusion, diffusion-weighted MRI with ADC mapping is a new promising technique that can differentiate malignant from benign lymph nodes and delineate the solid viable part of the lymph node for biopsy. This technique provides additional useful physiological and functional information regarding characterization of cervical lymph nodes.
El d eficit neurol ogico postoperatorio es la complicaci on m as devastadora despu es de la corre... more El d eficit neurol ogico postoperatorio es la complicaci on m as devastadora despu es de la correcci on de un aneurisma a ortico toracoabdominal. El objetivo del presente estudio fue investigar si el nebivolol tiene efectos protectores durante la isquemia o reperfusi on y el mecanismo de protecci on m as eficaz a trav es de la inhibici on de la liberaci on de oxido n ıtrico (ON) con un inhibidor de la ON sintasa en un modelo experimental de lesi on por isquemia/reperfusi on de la m edula espinal. La isquemia se indujo mediante oclusi on de la aorta infrarrenal durante 30 min. Dividimos a 31 conejos en cinco grupos de acuerdo con el per ıodo de administraci on de nebivolol y/o N G -nitro-L-arginina metil ester (L-NAME): grupo de control; grupo NI, nevibolol durante el per ıodo isqu emico; grupo NR, nevibolol durante el per ıodo de reperfusi on; grupo NILR, nebivolol durante el per ıodo isqu emico y L-NAME durante el per ıodo de reperfusi on; y grupo LINR, L-NAME durante el per ıodo isqu emico y nebivolol durante el per ıodo de reperfusi on. Se obtuvieron muestras de sangre en el per ıodo tanto de isquemia como de reperfusi on para determinar los niveles de nitrito/nitrato. Despu es de una evaluaci on neurol ogica a las 24 h de la reperfusi on, se determinaron los niveles de malondialdeh ıdo (MDA). El deterioro neurol ogico fue significativamente menor en el grupo LINR (puntuaci on de Tarlov 3,4 ± 0,6, p < 0,05). Los niveles de MDA fueron m as bajos en animales tratados con nebivolol, pero el valor m as bajo se alcanz o en el grupo NR, 35,6 ± 2,7 nmol/g ( p < 0,001). Los niveles de nitritos disminuyeron significativamente en todos los animales tratados con nebivolol en el per ıodo de reperfusi on, pero el valor m as bajo se determin o en el grupo LINR (455 ± 137 comparado con 1.760 ± 522 nmol/ml, p < 0,001). El uso profil actico de nebivolol redujo la lesi on neurol ogica, y, combinado con L-NAME, produjo la mayor mejor ıa cl ınica atenuando el medio inflamatorio en el modelo experimental. La combinaci on de nebivolol y L-NAME parece ser una opci on eficaz como protecci on de la m edula espinal frente a la lesi on por isquemia/reperfusi on.
Postoperative neurologic deficit is the most devastating complication after thoracoabdominal aort... more Postoperative neurologic deficit is the most devastating complication after thoracoabdominal aortic aneurysm repair. Our aim was to investigate whether nebivolol has protective effects during ischemia or reperfusion and the most effective mechanism of protection via inhibiting nitric oxide (NO) release with an NO synthase inhibitor in an experimental model of spinal cord ischemia/reperfusion injury. Spinal cord ischemia was induced by occlusion of the infrarenal aorta for 30 min. Thirty-one rabbits were divided into five groups according to the administration period of nebivolol and/or N(G)-nitro-L-arginine methyl ester (L-NAME): control group; group NI, nebivolol during ischemic period; group NR, nebivolol during reperfusion period; group NILR, nebivolol during ischemic period and L-NAME during reperfusion period; and group LINR, L-NAME during ischemic period and nebivolol during reperfusion period. Blood samples were taken at both ischemia and reperfusion periods to obtain nitrite/nitrate levels. After neurologic evaluation at 24 hr of reperfusion, malondialdehyde (MDA) levels were measured. Neurologic impairment was significantly lower in group LINR (Tarlov score 3.4 +/- 0.6, p &lt; 0.05). MDA levels were lower in nebivolol-treated animals, but the lowest value was achieved in the NR group, 35.6 +/- 2.7 nmol/g (p &lt; 0.001). Nitrite levels were decreased significantly in all nebivolol-treated animals in the reperfusion period, but the lowest value was measured in the LINR group (455 +/- 137 vs. 1,760 +/- 522 nmol/mL, p &lt; 0.001). Prophylactic use of nebivolol reduced neurologic injury, and combining with L-NAME provided the best clinical improvement by attenuating the inflammatory mileu in this experimental model. Combination of nebivolol and L-NAME appears to be an effective option for spinal cord protection against ischemia/reperfusion injury.
Summary: We sought to determine if there are differences in the incidence of seizure disorders b... more Summary: We sought to determine if there are differences in the incidence of seizure disorders between the children of the indigenous and immigrant (predominantly Pakistani) populations of Bradford, United Kingdom. Annual incidence rates per 100,000 for new onset seizures were calculated along with Townsend deprivation scores. The incidence of seizures (including febrile and single) was 153 (95%CI 104–139). The rate was significantly higher in south Asians (SA) (220; 184–255) compared to non–south Asians (non-SA) (121; 104–139), mainly because of febrile seizures whose incidence was 87 (136–169) overall and 142 (114–170) and 61 (49–74) in SA and non-SA, respectively. There were no significant differences in the rates of nonfebrile seizures (non-FebSz) overall and of idiopathic non-FebSz between racial groups but the rate for symptomatic/cryptogenic non-FebSz was significantly higher in SA (22; 10–34) compared to non-SA (6; 2–10). The occurrence of seizure disorders correlated with social deprivation.
Bu çalışmanın amacı, sağlık kurumlarında finansal performansı ölçmek amacıyla kullanılan yöntemle... more Bu çalışmanın amacı, sağlık kurumlarında finansal performansı ölçmek amacıyla kullanılan yöntemleri açıklamak ve Sağlık Bakanlığı Hastanelerini finansal performans düzeylerine göre sınıflandırmaktır. Hastanelerin sınıflandırılmasında finansal araştırmalarda kullanımı giderek yaygınlaşan veri madenciliği tekniğinden yararlanılmıştır. Çalışma kapsamına Sağlık Bakanlığına ait döner sermaye işletmesi olan 645 hastane alınmış ve analizlerde hastanelerin 2004 yılı verileri kullanılmıştır. Analizler sonucunda, araştırma kapsamındaki kamu hastanelerinin % 90,85’inin finansal
We have examined the effect of subchronic methidathion (MD) administration on heart damage, and h... more We have examined the effect of subchronic methidathion (MD) administration on heart damage, and have evaluated possible ameliorating effects of a combination of vitamins E and C against MD toxicity. The experimental groups were: control group, rats treated with 5 mg/kg 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 5 days a week for four weeks at a dose level of 5 mg/kg/day (MD and MD+Vit) by using corn oil as the vehicle. Vitamin E and vitamin C were injected at doses of 50 mg/kg i.m. and 20 mg/kg i.p., respectively, after the treatment with MD in the MD+ Vit group. The levels of malondialdehyde (MDA) were determined in the heart tissue, and the levels of cardiac troponin I (TnI) in serum. An autoanalyser was used to determine the serum activities of cholinesterase (ChE). Histopathological examination was carried out in the heart tissue. MDA significantly increased in the MD group as compared to controls (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). When MD was given concurrently with vitamins E and C, the increase in MDA was significantly less (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). ChE activity significantly decreased in the MD group as compared to controls (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). When MD was given concurrently with vitamins E and C, the decrease in ChE activity was significantly higher (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). The serum TnI levels significantly increased in the MD group as compared to controls (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). When MD was given concurrently with vitamins E and C, the increase in the serum TnI was significantly less (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). MD caused the diffuse loss of striation and myocytolysis of the cardiomyocytes, whereas the combination of vitamins E and C caused a significant decrease in these effects of MD. In conclusion, subchronic MD administration caused heart damage and, in addition, treatment with a combination of vitamins E and C after the administration of MD reduced heart damage caused by MD.
Inflammatory bowel disease (IBD) is an idiopathic inflammatory disease of the gastrointestinal tr... more Inflammatory bowel disease (IBD) is an idiopathic inflammatory disease of the gastrointestinal tract. The pathophysiology of IBD is probably the result of the complex interaction of genetic susceptibility and environmental influences. There is a well-known risk of thrombosis in patients with IBD. We present the case of a 53-year-old man with ulcerative colitis, who spontaneously developed intracranial sinus thrombosis that was treated with low molecular weight heparin. Literature was searched to assess the frequency and characteristics of cerebral sinus thrombosis in IBD and the role of certain etiopathological factors in such thrombotic patients.
We have examined the effect of subchronic methidathion (MD) administration on vascular wall damag... more We have examined the effect of subchronic methidathion (MD) administration on vascular wall damage. The experimental groups were: control group and rats treated with 5 mg/kg MD. The MD group was given MD by gavage for 5 days a week for 4 weeks at a dose level of 5 mg/kg per day by using corn oil as the vehicle. The levels of malondialdehyde (MDA) were determined in the vascular tissue. Histopathological examination was examined in the thoracic aortic tissue. The levels of MDA were increased in the MD group compared with the control group (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). In the MD group, subchronic MD administration led to the irregulation, prominent breaks and fragmentation of the elastic fibers were located in the media of aortic wall. In conclusion, it is likely that subchronic MD administration caused vascular wall damage and, in addition, lipid peroxidation may be one of the molecular mechanisms involved in MD-induced vascular toxicity.
The aim of this prospective, multicenter study was to define the etiology and clinical features o... more The aim of this prospective, multicenter study was to define the etiology and clinical features of acute kidney injury (AKI) in a pediatric patient cohort and to determine prognostic factors. Pediatric-modified RIFLE (pRIFLE) criteria were used to classify AKI. The patient cohort comprised 472 pediatric patients (264 males, 208 females), of whom 32.6% were newborns (median age 3 days, range 1–24 days), and 67.4% were children aged >1 month (median 2.99 years, range 1 month–18 years). The most common medical conditions were prematurity (42.2%) and congenital heart disease (CHD, 11.7%) in newborns, and malignancy (12.9%) and CHD (12.3%) in children aged >1 month. Hypoxic/ischemic injury and sepsis were the leading causes of AKI in both age groups. Dialysis was performed in 30.3% of newborns and 33.6% of children aged >1 month. Mortality was higher in the newborns (42.6 vs. 27.9%; p < 0.005). Stepwise multiple regression analysis revealed the major independent risk factors to be mechanical ventilation [relative risk (RR) 17.31, 95% confidence interval (95% CI) 4.88–61.42], hypervolemia (RR 12.90, 95% CI 1.97–84.37), CHD (RR 9.85, 95% CI 2.08–46.60), and metabolic acidosis (RR 7.64, 95% CI 2.90–20.15) in newborns and mechanical ventilation (RR 8.73, 95% CI 3.95–19.29), hypoxia (RR 5.35, 95% CI 2.26–12.67), and intrinsic AKI (RR 4.91, 95% CI 2.04–11.78) in children aged >1 month.
Ebselen (2-phenly-1, 2-benzisoselenazol-3[2H]-one) is a seleno-organic compound exhibiting both g... more Ebselen (2-phenly-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 2induced 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. D
Naunyn-schmiedebergs Archives of Pharmacology, 2006
Pramipexole, a novel non-ergot dopamine (DA) agonist, has been successfully applied to the treatm... more Pramipexole, a novel non-ergot dopamine (DA) agonist, has been successfully applied to the treatment of Parkinson’s disease (PD). Although the specific cause of PD remains unknown, recent studies have provided evidence that oxidative stress plays a role in the parthenogenesis of the disease. In the present study, we examined the effect of pramipexole on hydrogen peroxide (H2O2, 100 μM)-induced PC12 cell death, and the intracellular mechanism of this effect. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay revealed that pretreatment of PC12 cells with pramipexole (1–100 μM) resulted in significant protection against H2O2-induced cell death in a concentration-dependent manner. The protective effect of pramipexole was not affected by pretreatment with the DA receptor antagonists sulpiride, spiperone or domperidone, suggesting that the effect of pramipexole is not mediated by DA receptors. In PC12 cells, pramipexole inhibited H2O2-induced lactate dehydrogenase (LDH) leakage, as well as H2O2-induced cytochrome c release and caspase-3 activation with the resultant apoptosis. It was also observed in PC12 cells that H2O2 stimulated phosphorylation of mitogen-activated protein (MAP) kinases, i.e., extracellular signal-regulated kinase1/2 (ERK1/2), c-Jun NH2-terminal kinase (JNK) and p38 MAP kinase. Pramipexole inhibited H2O2-induced JNK and p38 MAP kinase, but not ERK1/2 phosphorylation. Furthermore, in these cells experiments with a fluorescent probe, 2-[6-(4'-amino)phenoxy-3H-xanthen-3-on-9-yl]benzoic acid, revealed that pramipexole, the JNK inhibitor SP600125 and the p38 MAP kinase inhibitor SB203580 inhibited the generation of H2O2-induced reactive oxygen species. Caspase inhibitors Z-DEVD-FMK and Z-IETD-FMK, as well as SP600125 and SB203580, inhibited H2O2-induced PC12 cell death to a similar extent as pramipexole. These results suggest that pramipexole exerts a protective effect against oxidative stress-induced PC12 cell death in part through an inhibition of JNK and p38 MAP kinase.
Clinical evidence suggests a relationship between hypertension and insulin resistance, and cross-... more Clinical evidence suggests a relationship between hypertension and insulin resistance, and cross-talk between angiotensin II (Ang II) and insulin signaling pathways may take place. We now report the effect of Ang II on insulin-induced glucose uptake and its intracellular mechanisms in vascular smooth muscle cells (VSMC). We examined the translocation of glucose transporter-4 (GLUT-4) and glucose uptake in rat aortic smooth muscle cells (RASMC). Mitogen-activated protein (MAP) kinases and Akt activities, and phosphorylation of insulin receptor substrate-1 (IRS-1) at the serine and tyrosine residues were measured by immunoprecipitation and immunoblotting. As a result, Ang II inhibited insulin-induced GLUT-4 translocation from cytoplasm to the plasma membrane in RASMC. Ang II induced extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK) activation and IRS-1 phosphorylation at Ser307 and Ser616. Ang II-induced Ser307 and Ser616 phophorylation of IRS-1 was inhibited by a MEK inhibitor, PD98059, and a JNK inhibitor, SP600125. Ang II inhibition of insulin-stimulated IRS-1 tyrosyl phophorylation and Akt activation were reversed by PD98059 but not by SP600125. Ang II inhibited insulin-induced glucose uptake, which was also reversed by PD98059 but not by SP600125. It is shown that Ang II-induced ERK1/2 activation inhibits insulin-dependent glucose uptake through serine phophorylation of IRS-1 in RASMC.
We examined the effects of the stereoisomers of N-acetylcysteine (NAC), L-NAC and D-NAC, on cellu... more We examined the effects of the stereoisomers of N-acetylcysteine (NAC), L-NAC and D-NAC, on cellular glutathione (GSH) concentration and whether NAC-regulated cellular GSH levels are directly associated with angiotensin II (Ang II)-induced intracellular signaling events in vascular smooth muscle cells (VSMC). Both L-NAC and D-NAC similarly increased intracellular GSH concentration. We found that L-NAC and D-NAC both inhibited Ang II-induced c-Jun N-terminal kinase and p38 mitogen-activated protein kinase activation and [(3)H]-thymidine incorporation in VSMC. Our present study indicates the comparable effects of NAC stereoisomers in regulating intracellular GSH and the redox-dependent intracellular signaling mechanisms in VSMC.
Vascular endothelial growth factor (VEGF) was reported to be a potent proangiogenic factor that p... more Vascular endothelial growth factor (VEGF) was reported to be a potent proangiogenic factor that plays a pivotal role in both physiological and pathological angiogenesis. M475271, 4-quinazolinamine, N-(2-chloro-5-methoxyphenyl)-6-methoxy-7-[(1-methyl-4-piperidinyl) methoxy]-(9Cl), is a new anilinoquinazoline derivative that showed selective inhibition of Src kinase activity and tumor growth in vivo. Here, we examined the effect of M475271 on VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation and migration and their intracellular mechanisms. Our findings showed that M475271 pretreatment resulted in a significant inhibition of VEGF-induced HUVEC proliferation, [(3)H]thymidine incorporation, and migration. M475271 inhibited VEGF-induced Flk-1 and Src phosphorylation and their association. Confocal laser microscopic examination confirmed the inhibitory effect of M475271 on VEGF-induced Flk-1/Src association. M475271 inhibited VEGF-induced extracellular signal-regulated kinase1/2 (ERK1/2) and p38 but not Akt activation in a concentration-dependent manner. M475271, PI3-K inhibitor, and p38 inhibitor inhibited VEGF-induced HUVEC proliferation and migration. However, a MEK1/2 inhibitor inhibited VEGF-induced proliferation but not migration. These findings suggest that M475271 attenuates VEGF-induced HUVEC proliferation and migration through the inhibition of signaling pathways involving Src, ERK1/2, and/or p38. Taken together, these data indicate that M475271 may be a useful candidate for inhibition of endothelial cell proliferation and migration relevant to angiogenesis.
Lysophosphatidylcholine (LPC), a major lipid component of oxidized low-density lipoprotein, is a ... more Lysophosphatidylcholine (LPC), a major lipid component of oxidized low-density lipoprotein, is a bioactive lipid molecule involved in numerous biological processes including the progression of atherosclerosis. Recently orphan G protein-coupled receptors were identified as high-affinity receptors for LPC. Although several G protein-coupled receptor ligands transactivate receptor tyrosine kinases, LPC-stimulated transactivation of receptor tyrosine kinase has not yet been reported. Here we observed for the first time that LPC treatment of human umbilical vein endothelial cells (HUVECs) induces tyrosyl phosphorylation of vascular endothelial growth factor receptor 2 [fetal liver kinase-1/kinase-insert domain-containing receptor, Flk-1/KDR)]. Flk-1/KDR transactivation by LPC was inhibited by vascular endothelial growth factor receptor tyrosine kinase inhibitors, SU1498 and 4-[(4&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-chloro-2&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-fluoro) phenylamino]6,7-dimethoxyquinazoline (VTKi) in immunoprecipitation. Furthermore, we examined the effects of the Src family kinases inhibitors, herbimycin A and 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo[3,4-d] pyrimidine (PP2), on LPC-induced Flk-1/KDR transactivation. Results from Western blots, c-Src is involved in LPC-induced Flk-1/KDR transactivation because herbimycin A and PP2 inhibited this transactivation. Kinase-inactive (KI) Src transfection also inhibited LPC-induced Flk-1/KDR transactivation. In addition, results from Western blots, ERK1/2 and Akt, which are downstream effectors of Flk-1/KDR, were also activated by LPC, and this was inhibited by SU1498, VTKi, herbimycin A, PP2, and KI Src transfection in HUVECs. LPC-induced stimulation of HUVEC proliferation was shown to be secondary to transactivation because it was suppressed by SU1498, VTKi, herbimycin A, PP2, and KI Src transfection in dimethylthiazoldiphenyltetra-zoliumbromide assay. These findings suggest that LPC-induced Flk-1/KDR transactivation via c-Src may have important implications for the progression of atherosclerosis.
Vascular endothelial growth factor (VEGF) was reported to be a potent proangiogenic factor that p... more Vascular endothelial growth factor (VEGF) was reported to be a potent proangiogenic factor that plays a pivotal role in both physiological and pathological angiogenesis. M475271, 4-quinazolinamine, N-(2-chloro-5-methoxyphenyl)-6-methoxy-7-[(1-methyl-4-piperidinyl) methoxy]-(9Cl), is a new anilinoquinazoline derivative that showed selective inhibition of Src kinase activity and tumor growth in vivo. Here, we examined the effect of M475271 on VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation and migration and their intracellular mechanisms. Our findings showed that M475271 pretreatment resulted in a significant inhibition of VEGF-induced HUVEC proliferation, [(3)H]thymidine incorporation, and migration. M475271 inhibited VEGF-induced Flk-1 and Src phosphorylation and their association. Confocal laser microscopic examination confirmed the inhibitory effect of M475271 on VEGF-induced Flk-1/Src association. M475271 inhibited VEGF-induced extracellular signal-regulated kinase1/2 (ERK1/2) and p38 but not Akt activation in a concentration-dependent manner. M475271, PI3-K inhibitor, and p38 inhibitor inhibited VEGF-induced HUVEC proliferation and migration. However, a MEK1/2 inhibitor inhibited VEGF-induced proliferation but not migration. These findings suggest that M475271 attenuates VEGF-induced HUVEC proliferation and migration through the inhibition of signaling pathways involving Src, ERK1/2, and/or p38. Taken together, these data indicate that M475271 may be a useful candidate for inhibition of endothelial cell proliferation and migration relevant to angiogenesis.
Tumor necrosis factor-a (TNF-a) stimulates expression of endothelial cell (EC) genes that may pro... more Tumor necrosis factor-a (TNF-a) stimulates expression of endothelial cell (EC) genes that may promote atherosclerosis in part by an activation of mitogen-activated protein (MAP) kinases. Ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]-one), a selenoorganic compound, is effective for acute ischemic stroke; however, its effect on EC has not yet been elucidated. We examined the effect of ebselen on TNF-a-induced MAP kinase activation and adhesion molecule expression in cultured human umbilical vein endothelial cells (HUVEC). Extracellular signalregulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 were rapidly and significantly activated by TNF-a in HUVEC. TNF-ainduced JNK activation was inhibited by ebselen, whereas ERK1/2 and p38 were not affected. Apoptosis signal-regulated kinase 1 (ASK1) was suggested to be involved in TNF-a-induced JNK activation because transfection of kinase-inactive ASK1 inhibited TNF-a-induced JNK activation. Ebselen inhibited TNF-a-induced TNF receptor-associated factor 2 (TRAF2) -ASK1 complex formation and phosphorylation of stress-activated protein kinase ERK kinase 1 (SEK1), which is an upstream signaling molecule of JNK. Finally, TNF-a-induced activator protein-1 (AP-1) and nuclear factor-nB (NF-nB) activation and resultant intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expressions were inhibited by ebselen. Specific inhibitors for JNK and NF-nB also inhibited TNF-a-induced ICAM-1 and VCAM-1 expressions in HUVEC. These findings suggest that ebselen prevents TNF-a-induced EC activation through the inhibition of TRAF2-ASK1-SEK1 signaling pathway, which leads to JNK activation. Inhibition of JNK by ebselen may imply its usefulness for the prevention of atherosclerosis relevant to EC activation. D
Ghrelin and obestatin are a single gene products and are a multiple functional peptides that regu... more Ghrelin and obestatin are a single gene products and are a multiple functional peptides that regulates energy homeostasis, and food intake. In the present work, we studied the secretion of ghrelin and its co-secreted peptide obestatin in 44 patients with ischemic heart disease with that of 27 healthy matched controls. Here we first conducted using an immunohistochemistry assay to screen whether human salivary glands have any obestatin immunoreactivity. Then, serum and saliva obestatin and acylated ghrelin levels were determined by using Radioimmunoassay. Our immunohistochemical analysis demonstrated that obestatin was localized in the striated and excretory duct of human salivary gland. We also report for the first time that obestatin, like ghrelin, is present in human salivary gland and saliva. No evidence of the role of obestatin or ghrelin saliva levels in the context of ischemic heart disease was found. Salivary ghrelin and obestatin levels are correlated in controls with the blood levels. Determination of salivary values could represent a non-invasive alternative to serum ones that can be useful in clinical practice. [BMB reports 2008; 41(1): 55-61]
The role of diffusion-weighted magnetic resonance imaging (MRI) for differentiation between vario... more The role of diffusion-weighted magnetic resonance imaging (MRI) for differentiation between various causes of cervical lymphadenopathy was evaluated. In a prospective study, 31 untreated patients (22 males and nine females, aged 5–70 years) with 87 cervical lymph nodes underwent diffusion-weighted MRI before performance of neck dissection (n=14), surgical biopsy (n=9) or core biopsy (n=8). Diffusion-weighted MR images were acquired with a b factor of 0 and 1,000 s/mm2 using single-shot echo-planar sequence. Apparent diffusion coefficient (ADC) maps were reconstructed for all patients. The signal intensity of the lymph nodes was assessed on images obtained at b=0 or 1,000 s/mm2 and from the ADC maps. The ADC value of lymph nodes was also calculated. On the ADC map, malignant nodes showed either low (n=52) or mixed (n=20) signal intensity and benign nodes revealed high (n=13) or low (n=2) signal intensity. The mean ADC value of metastatic (1.09±0.11×10−3 mm2/s) and lymphomatous (0.97±0.27×10−3 mm2/s) lymph nodes was significantly lower than that of benign (1.64±0.16×10−3 mm2/s) cervical lymph nodes (P<0.04). When an ADC value of 1.38×10−3 mm2/s was used as a threshold value for differentiating malignant from benign lymph nodes, the best results were obtained with an accuracy of 96%, sensitivity of 98%, specificity of 88%, positive predictive value of 98.5% and negative predictive value of 83.7%. The smallest detected lymph node was 0.9 cm. In conclusion, diffusion-weighted MRI with ADC mapping is a new promising technique that can differentiate malignant from benign lymph nodes and delineate the solid viable part of the lymph node for biopsy. This technique provides additional useful physiological and functional information regarding characterization of cervical lymph nodes.
El d eficit neurol ogico postoperatorio es la complicaci on m as devastadora despu es de la corre... more El d eficit neurol ogico postoperatorio es la complicaci on m as devastadora despu es de la correcci on de un aneurisma a ortico toracoabdominal. El objetivo del presente estudio fue investigar si el nebivolol tiene efectos protectores durante la isquemia o reperfusi on y el mecanismo de protecci on m as eficaz a trav es de la inhibici on de la liberaci on de oxido n ıtrico (ON) con un inhibidor de la ON sintasa en un modelo experimental de lesi on por isquemia/reperfusi on de la m edula espinal. La isquemia se indujo mediante oclusi on de la aorta infrarrenal durante 30 min. Dividimos a 31 conejos en cinco grupos de acuerdo con el per ıodo de administraci on de nebivolol y/o N G -nitro-L-arginina metil ester (L-NAME): grupo de control; grupo NI, nevibolol durante el per ıodo isqu emico; grupo NR, nevibolol durante el per ıodo de reperfusi on; grupo NILR, nebivolol durante el per ıodo isqu emico y L-NAME durante el per ıodo de reperfusi on; y grupo LINR, L-NAME durante el per ıodo isqu emico y nebivolol durante el per ıodo de reperfusi on. Se obtuvieron muestras de sangre en el per ıodo tanto de isquemia como de reperfusi on para determinar los niveles de nitrito/nitrato. Despu es de una evaluaci on neurol ogica a las 24 h de la reperfusi on, se determinaron los niveles de malondialdeh ıdo (MDA). El deterioro neurol ogico fue significativamente menor en el grupo LINR (puntuaci on de Tarlov 3,4 ± 0,6, p < 0,05). Los niveles de MDA fueron m as bajos en animales tratados con nebivolol, pero el valor m as bajo se alcanz o en el grupo NR, 35,6 ± 2,7 nmol/g ( p < 0,001). Los niveles de nitritos disminuyeron significativamente en todos los animales tratados con nebivolol en el per ıodo de reperfusi on, pero el valor m as bajo se determin o en el grupo LINR (455 ± 137 comparado con 1.760 ± 522 nmol/ml, p < 0,001). El uso profil actico de nebivolol redujo la lesi on neurol ogica, y, combinado con L-NAME, produjo la mayor mejor ıa cl ınica atenuando el medio inflamatorio en el modelo experimental. La combinaci on de nebivolol y L-NAME parece ser una opci on eficaz como protecci on de la m edula espinal frente a la lesi on por isquemia/reperfusi on.
Postoperative neurologic deficit is the most devastating complication after thoracoabdominal aort... more Postoperative neurologic deficit is the most devastating complication after thoracoabdominal aortic aneurysm repair. Our aim was to investigate whether nebivolol has protective effects during ischemia or reperfusion and the most effective mechanism of protection via inhibiting nitric oxide (NO) release with an NO synthase inhibitor in an experimental model of spinal cord ischemia/reperfusion injury. Spinal cord ischemia was induced by occlusion of the infrarenal aorta for 30 min. Thirty-one rabbits were divided into five groups according to the administration period of nebivolol and/or N(G)-nitro-L-arginine methyl ester (L-NAME): control group; group NI, nebivolol during ischemic period; group NR, nebivolol during reperfusion period; group NILR, nebivolol during ischemic period and L-NAME during reperfusion period; and group LINR, L-NAME during ischemic period and nebivolol during reperfusion period. Blood samples were taken at both ischemia and reperfusion periods to obtain nitrite/nitrate levels. After neurologic evaluation at 24 hr of reperfusion, malondialdehyde (MDA) levels were measured. Neurologic impairment was significantly lower in group LINR (Tarlov score 3.4 +/- 0.6, p &lt; 0.05). MDA levels were lower in nebivolol-treated animals, but the lowest value was achieved in the NR group, 35.6 +/- 2.7 nmol/g (p &lt; 0.001). Nitrite levels were decreased significantly in all nebivolol-treated animals in the reperfusion period, but the lowest value was measured in the LINR group (455 +/- 137 vs. 1,760 +/- 522 nmol/mL, p &lt; 0.001). Prophylactic use of nebivolol reduced neurologic injury, and combining with L-NAME provided the best clinical improvement by attenuating the inflammatory mileu in this experimental model. Combination of nebivolol and L-NAME appears to be an effective option for spinal cord protection against ischemia/reperfusion injury.
Summary: We sought to determine if there are differences in the incidence of seizure disorders b... more Summary: We sought to determine if there are differences in the incidence of seizure disorders between the children of the indigenous and immigrant (predominantly Pakistani) populations of Bradford, United Kingdom. Annual incidence rates per 100,000 for new onset seizures were calculated along with Townsend deprivation scores. The incidence of seizures (including febrile and single) was 153 (95%CI 104–139). The rate was significantly higher in south Asians (SA) (220; 184–255) compared to non–south Asians (non-SA) (121; 104–139), mainly because of febrile seizures whose incidence was 87 (136–169) overall and 142 (114–170) and 61 (49–74) in SA and non-SA, respectively. There were no significant differences in the rates of nonfebrile seizures (non-FebSz) overall and of idiopathic non-FebSz between racial groups but the rate for symptomatic/cryptogenic non-FebSz was significantly higher in SA (22; 10–34) compared to non-SA (6; 2–10). The occurrence of seizure disorders correlated with social deprivation.
Bu çalışmanın amacı, sağlık kurumlarında finansal performansı ölçmek amacıyla kullanılan yöntemle... more Bu çalışmanın amacı, sağlık kurumlarında finansal performansı ölçmek amacıyla kullanılan yöntemleri açıklamak ve Sağlık Bakanlığı Hastanelerini finansal performans düzeylerine göre sınıflandırmaktır. Hastanelerin sınıflandırılmasında finansal araştırmalarda kullanımı giderek yaygınlaşan veri madenciliği tekniğinden yararlanılmıştır. Çalışma kapsamına Sağlık Bakanlığına ait döner sermaye işletmesi olan 645 hastane alınmış ve analizlerde hastanelerin 2004 yılı verileri kullanılmıştır. Analizler sonucunda, araştırma kapsamındaki kamu hastanelerinin % 90,85’inin finansal
We have examined the effect of subchronic methidathion (MD) administration on heart damage, and h... more We have examined the effect of subchronic methidathion (MD) administration on heart damage, and have evaluated possible ameliorating effects of a combination of vitamins E and C against MD toxicity. The experimental groups were: control group, rats treated with 5 mg/kg 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 5 days a week for four weeks at a dose level of 5 mg/kg/day (MD and MD+Vit) by using corn oil as the vehicle. Vitamin E and vitamin C were injected at doses of 50 mg/kg i.m. and 20 mg/kg i.p., respectively, after the treatment with MD in the MD+ Vit group. The levels of malondialdehyde (MDA) were determined in the heart tissue, and the levels of cardiac troponin I (TnI) in serum. An autoanalyser was used to determine the serum activities of cholinesterase (ChE). Histopathological examination was carried out in the heart tissue. MDA significantly increased in the MD group as compared to controls (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). When MD was given concurrently with vitamins E and C, the increase in MDA was significantly less (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). ChE activity significantly decreased in the MD group as compared to controls (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). When MD was given concurrently with vitamins E and C, the decrease in ChE activity was significantly higher (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). The serum TnI levels significantly increased in the MD group as compared to controls (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). When MD was given concurrently with vitamins E and C, the increase in the serum TnI was significantly less (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). MD caused the diffuse loss of striation and myocytolysis of the cardiomyocytes, whereas the combination of vitamins E and C caused a significant decrease in these effects of MD. In conclusion, subchronic MD administration caused heart damage and, in addition, treatment with a combination of vitamins E and C after the administration of MD reduced heart damage caused by MD.
Inflammatory bowel disease (IBD) is an idiopathic inflammatory disease of the gastrointestinal tr... more Inflammatory bowel disease (IBD) is an idiopathic inflammatory disease of the gastrointestinal tract. The pathophysiology of IBD is probably the result of the complex interaction of genetic susceptibility and environmental influences. There is a well-known risk of thrombosis in patients with IBD. We present the case of a 53-year-old man with ulcerative colitis, who spontaneously developed intracranial sinus thrombosis that was treated with low molecular weight heparin. Literature was searched to assess the frequency and characteristics of cerebral sinus thrombosis in IBD and the role of certain etiopathological factors in such thrombotic patients.
We have examined the effect of subchronic methidathion (MD) administration on vascular wall damag... more We have examined the effect of subchronic methidathion (MD) administration on vascular wall damage. The experimental groups were: control group and rats treated with 5 mg/kg MD. The MD group was given MD by gavage for 5 days a week for 4 weeks at a dose level of 5 mg/kg per day by using corn oil as the vehicle. The levels of malondialdehyde (MDA) were determined in the vascular tissue. Histopathological examination was examined in the thoracic aortic tissue. The levels of MDA were increased in the MD group compared with the control group (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). In the MD group, subchronic MD administration led to the irregulation, prominent breaks and fragmentation of the elastic fibers were located in the media of aortic wall. In conclusion, it is likely that subchronic MD administration caused vascular wall damage and, in addition, lipid peroxidation may be one of the molecular mechanisms involved in MD-induced vascular toxicity.
The aim of this prospective, multicenter study was to define the etiology and clinical features o... more The aim of this prospective, multicenter study was to define the etiology and clinical features of acute kidney injury (AKI) in a pediatric patient cohort and to determine prognostic factors. Pediatric-modified RIFLE (pRIFLE) criteria were used to classify AKI. The patient cohort comprised 472 pediatric patients (264 males, 208 females), of whom 32.6% were newborns (median age 3 days, range 1–24 days), and 67.4% were children aged >1 month (median 2.99 years, range 1 month–18 years). The most common medical conditions were prematurity (42.2%) and congenital heart disease (CHD, 11.7%) in newborns, and malignancy (12.9%) and CHD (12.3%) in children aged >1 month. Hypoxic/ischemic injury and sepsis were the leading causes of AKI in both age groups. Dialysis was performed in 30.3% of newborns and 33.6% of children aged >1 month. Mortality was higher in the newborns (42.6 vs. 27.9%; p < 0.005). Stepwise multiple regression analysis revealed the major independent risk factors to be mechanical ventilation [relative risk (RR) 17.31, 95% confidence interval (95% CI) 4.88–61.42], hypervolemia (RR 12.90, 95% CI 1.97–84.37), CHD (RR 9.85, 95% CI 2.08–46.60), and metabolic acidosis (RR 7.64, 95% CI 2.90–20.15) in newborns and mechanical ventilation (RR 8.73, 95% CI 3.95–19.29), hypoxia (RR 5.35, 95% CI 2.26–12.67), and intrinsic AKI (RR 4.91, 95% CI 2.04–11.78) in children aged >1 month.
Ebselen (2-phenly-1, 2-benzisoselenazol-3[2H]-one) is a seleno-organic compound exhibiting both g... more Ebselen (2-phenly-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 2induced 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. D
Naunyn-schmiedebergs Archives of Pharmacology, 2006
Pramipexole, a novel non-ergot dopamine (DA) agonist, has been successfully applied to the treatm... more Pramipexole, a novel non-ergot dopamine (DA) agonist, has been successfully applied to the treatment of Parkinson’s disease (PD). Although the specific cause of PD remains unknown, recent studies have provided evidence that oxidative stress plays a role in the parthenogenesis of the disease. In the present study, we examined the effect of pramipexole on hydrogen peroxide (H2O2, 100 μM)-induced PC12 cell death, and the intracellular mechanism of this effect. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay revealed that pretreatment of PC12 cells with pramipexole (1–100 μM) resulted in significant protection against H2O2-induced cell death in a concentration-dependent manner. The protective effect of pramipexole was not affected by pretreatment with the DA receptor antagonists sulpiride, spiperone or domperidone, suggesting that the effect of pramipexole is not mediated by DA receptors. In PC12 cells, pramipexole inhibited H2O2-induced lactate dehydrogenase (LDH) leakage, as well as H2O2-induced cytochrome c release and caspase-3 activation with the resultant apoptosis. It was also observed in PC12 cells that H2O2 stimulated phosphorylation of mitogen-activated protein (MAP) kinases, i.e., extracellular signal-regulated kinase1/2 (ERK1/2), c-Jun NH2-terminal kinase (JNK) and p38 MAP kinase. Pramipexole inhibited H2O2-induced JNK and p38 MAP kinase, but not ERK1/2 phosphorylation. Furthermore, in these cells experiments with a fluorescent probe, 2-[6-(4'-amino)phenoxy-3H-xanthen-3-on-9-yl]benzoic acid, revealed that pramipexole, the JNK inhibitor SP600125 and the p38 MAP kinase inhibitor SB203580 inhibited the generation of H2O2-induced reactive oxygen species. Caspase inhibitors Z-DEVD-FMK and Z-IETD-FMK, as well as SP600125 and SB203580, inhibited H2O2-induced PC12 cell death to a similar extent as pramipexole. These results suggest that pramipexole exerts a protective effect against oxidative stress-induced PC12 cell death in part through an inhibition of JNK and p38 MAP kinase.
Clinical evidence suggests a relationship between hypertension and insulin resistance, and cross-... more Clinical evidence suggests a relationship between hypertension and insulin resistance, and cross-talk between angiotensin II (Ang II) and insulin signaling pathways may take place. We now report the effect of Ang II on insulin-induced glucose uptake and its intracellular mechanisms in vascular smooth muscle cells (VSMC). We examined the translocation of glucose transporter-4 (GLUT-4) and glucose uptake in rat aortic smooth muscle cells (RASMC). Mitogen-activated protein (MAP) kinases and Akt activities, and phosphorylation of insulin receptor substrate-1 (IRS-1) at the serine and tyrosine residues were measured by immunoprecipitation and immunoblotting. As a result, Ang II inhibited insulin-induced GLUT-4 translocation from cytoplasm to the plasma membrane in RASMC. Ang II induced extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK) activation and IRS-1 phosphorylation at Ser307 and Ser616. Ang II-induced Ser307 and Ser616 phophorylation of IRS-1 was inhibited by a MEK inhibitor, PD98059, and a JNK inhibitor, SP600125. Ang II inhibition of insulin-stimulated IRS-1 tyrosyl phophorylation and Akt activation were reversed by PD98059 but not by SP600125. Ang II inhibited insulin-induced glucose uptake, which was also reversed by PD98059 but not by SP600125. It is shown that Ang II-induced ERK1/2 activation inhibits insulin-dependent glucose uptake through serine phophorylation of IRS-1 in RASMC.
We examined the effects of the stereoisomers of N-acetylcysteine (NAC), L-NAC and D-NAC, on cellu... more We examined the effects of the stereoisomers of N-acetylcysteine (NAC), L-NAC and D-NAC, on cellular glutathione (GSH) concentration and whether NAC-regulated cellular GSH levels are directly associated with angiotensin II (Ang II)-induced intracellular signaling events in vascular smooth muscle cells (VSMC). Both L-NAC and D-NAC similarly increased intracellular GSH concentration. We found that L-NAC and D-NAC both inhibited Ang II-induced c-Jun N-terminal kinase and p38 mitogen-activated protein kinase activation and [(3)H]-thymidine incorporation in VSMC. Our present study indicates the comparable effects of NAC stereoisomers in regulating intracellular GSH and the redox-dependent intracellular signaling mechanisms in VSMC.
Vascular endothelial growth factor (VEGF) was reported to be a potent proangiogenic factor that p... more Vascular endothelial growth factor (VEGF) was reported to be a potent proangiogenic factor that plays a pivotal role in both physiological and pathological angiogenesis. M475271, 4-quinazolinamine, N-(2-chloro-5-methoxyphenyl)-6-methoxy-7-[(1-methyl-4-piperidinyl) methoxy]-(9Cl), is a new anilinoquinazoline derivative that showed selective inhibition of Src kinase activity and tumor growth in vivo. Here, we examined the effect of M475271 on VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation and migration and their intracellular mechanisms. Our findings showed that M475271 pretreatment resulted in a significant inhibition of VEGF-induced HUVEC proliferation, [(3)H]thymidine incorporation, and migration. M475271 inhibited VEGF-induced Flk-1 and Src phosphorylation and their association. Confocal laser microscopic examination confirmed the inhibitory effect of M475271 on VEGF-induced Flk-1/Src association. M475271 inhibited VEGF-induced extracellular signal-regulated kinase1/2 (ERK1/2) and p38 but not Akt activation in a concentration-dependent manner. M475271, PI3-K inhibitor, and p38 inhibitor inhibited VEGF-induced HUVEC proliferation and migration. However, a MEK1/2 inhibitor inhibited VEGF-induced proliferation but not migration. These findings suggest that M475271 attenuates VEGF-induced HUVEC proliferation and migration through the inhibition of signaling pathways involving Src, ERK1/2, and/or p38. Taken together, these data indicate that M475271 may be a useful candidate for inhibition of endothelial cell proliferation and migration relevant to angiogenesis.
Lysophosphatidylcholine (LPC), a major lipid component of oxidized low-density lipoprotein, is a ... more Lysophosphatidylcholine (LPC), a major lipid component of oxidized low-density lipoprotein, is a bioactive lipid molecule involved in numerous biological processes including the progression of atherosclerosis. Recently orphan G protein-coupled receptors were identified as high-affinity receptors for LPC. Although several G protein-coupled receptor ligands transactivate receptor tyrosine kinases, LPC-stimulated transactivation of receptor tyrosine kinase has not yet been reported. Here we observed for the first time that LPC treatment of human umbilical vein endothelial cells (HUVECs) induces tyrosyl phosphorylation of vascular endothelial growth factor receptor 2 [fetal liver kinase-1/kinase-insert domain-containing receptor, Flk-1/KDR)]. Flk-1/KDR transactivation by LPC was inhibited by vascular endothelial growth factor receptor tyrosine kinase inhibitors, SU1498 and 4-[(4&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-chloro-2&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;-fluoro) phenylamino]6,7-dimethoxyquinazoline (VTKi) in immunoprecipitation. Furthermore, we examined the effects of the Src family kinases inhibitors, herbimycin A and 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo[3,4-d] pyrimidine (PP2), on LPC-induced Flk-1/KDR transactivation. Results from Western blots, c-Src is involved in LPC-induced Flk-1/KDR transactivation because herbimycin A and PP2 inhibited this transactivation. Kinase-inactive (KI) Src transfection also inhibited LPC-induced Flk-1/KDR transactivation. In addition, results from Western blots, ERK1/2 and Akt, which are downstream effectors of Flk-1/KDR, were also activated by LPC, and this was inhibited by SU1498, VTKi, herbimycin A, PP2, and KI Src transfection in HUVECs. LPC-induced stimulation of HUVEC proliferation was shown to be secondary to transactivation because it was suppressed by SU1498, VTKi, herbimycin A, PP2, and KI Src transfection in dimethylthiazoldiphenyltetra-zoliumbromide assay. These findings suggest that LPC-induced Flk-1/KDR transactivation via c-Src may have important implications for the progression of atherosclerosis.
Vascular endothelial growth factor (VEGF) was reported to be a potent proangiogenic factor that p... more Vascular endothelial growth factor (VEGF) was reported to be a potent proangiogenic factor that plays a pivotal role in both physiological and pathological angiogenesis. M475271, 4-quinazolinamine, N-(2-chloro-5-methoxyphenyl)-6-methoxy-7-[(1-methyl-4-piperidinyl) methoxy]-(9Cl), is a new anilinoquinazoline derivative that showed selective inhibition of Src kinase activity and tumor growth in vivo. Here, we examined the effect of M475271 on VEGF-induced human umbilical vein endothelial cell (HUVEC) proliferation and migration and their intracellular mechanisms. Our findings showed that M475271 pretreatment resulted in a significant inhibition of VEGF-induced HUVEC proliferation, [(3)H]thymidine incorporation, and migration. M475271 inhibited VEGF-induced Flk-1 and Src phosphorylation and their association. Confocal laser microscopic examination confirmed the inhibitory effect of M475271 on VEGF-induced Flk-1/Src association. M475271 inhibited VEGF-induced extracellular signal-regulated kinase1/2 (ERK1/2) and p38 but not Akt activation in a concentration-dependent manner. M475271, PI3-K inhibitor, and p38 inhibitor inhibited VEGF-induced HUVEC proliferation and migration. However, a MEK1/2 inhibitor inhibited VEGF-induced proliferation but not migration. These findings suggest that M475271 attenuates VEGF-induced HUVEC proliferation and migration through the inhibition of signaling pathways involving Src, ERK1/2, and/or p38. Taken together, these data indicate that M475271 may be a useful candidate for inhibition of endothelial cell proliferation and migration relevant to angiogenesis.
Tumor necrosis factor-a (TNF-a) stimulates expression of endothelial cell (EC) genes that may pro... more Tumor necrosis factor-a (TNF-a) stimulates expression of endothelial cell (EC) genes that may promote atherosclerosis in part by an activation of mitogen-activated protein (MAP) kinases. Ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]-one), a selenoorganic compound, is effective for acute ischemic stroke; however, its effect on EC has not yet been elucidated. We examined the effect of ebselen on TNF-a-induced MAP kinase activation and adhesion molecule expression in cultured human umbilical vein endothelial cells (HUVEC). Extracellular signalregulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 were rapidly and significantly activated by TNF-a in HUVEC. TNF-ainduced JNK activation was inhibited by ebselen, whereas ERK1/2 and p38 were not affected. Apoptosis signal-regulated kinase 1 (ASK1) was suggested to be involved in TNF-a-induced JNK activation because transfection of kinase-inactive ASK1 inhibited TNF-a-induced JNK activation. Ebselen inhibited TNF-a-induced TNF receptor-associated factor 2 (TRAF2) -ASK1 complex formation and phosphorylation of stress-activated protein kinase ERK kinase 1 (SEK1), which is an upstream signaling molecule of JNK. Finally, TNF-a-induced activator protein-1 (AP-1) and nuclear factor-nB (NF-nB) activation and resultant intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expressions were inhibited by ebselen. Specific inhibitors for JNK and NF-nB also inhibited TNF-a-induced ICAM-1 and VCAM-1 expressions in HUVEC. These findings suggest that ebselen prevents TNF-a-induced EC activation through the inhibition of TRAF2-ASK1-SEK1 signaling pathway, which leads to JNK activation. Inhibition of JNK by ebselen may imply its usefulness for the prevention of atherosclerosis relevant to EC activation. D
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