Inhibition of extracellular signal-regulated kinase (ERK1/2) activity reverses endotoxin-induced hypotension via decreased nitric oxide production in rats.

Overproduction of reactive oxygen and nitrogen species leads to oxidative stress and decreased total antioxidant capacity, which is responsible for high mortality from several inflammatory diseases such as endotoxic shock. Among reactive nitrogen species, nitric oxide (NO) produced by inducible NO synthase (iNOS) during endotoxemia is the major cause of vascular hyporeactivity, hypotension and multiple organ failure. This study was conducted to determine if mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase (ERK1/2) contributes to endotoxin-induced hypotension as well as vascular inflammation and oxidative stress via NO production. In conscious male Wistar rats, injection of endotoxin (10 mg kg(-1), i.p.) caused a decrease in mean arterial pressure (MAP) for 4h and increased levels of nitrite in serum, aorta and mesenteric artery. These effects of endotoxin were prevented by selective inhibition of ERK1/2 phosphorylation by MAPK kinase (MEK1/2) with U0126 (5 mg kg(-1), i.p.; 1h after endotoxin). Endotoxin also caused an increase in protein levels of phosphorylated ERK1/2 in aorta which was abolished by U0126. Selective inhibition of iNOS with phenylene-1,3-bis[ethane-2-isothiourea] dihydrobromide (1,3-PBIT) (10 mg kg(-1), i.p.; 1h after endotoxin) did not change the endotoxin-induced increase in ERK1/2 activity. Myeloperoxidase activity was increased in aorta and decreased in mesenteric artery by endotoxin, which was reversed by U0126. Endotoxin-induced decrease in one of the products of lipid peroxidation, malonedialdehyde (MDA) was prevented by U0126 in mesenteric artery; however, U0126 caused a further decrease in the levels of MDA in aorta. These data suggest that increased phosphorylation of ERK1/2 by MEK1/2 contributes to the endotoxin-induced hypotension via NO production rat aorta and mesenteric artery. It is likely that ERK1/2 mediates the effect of endotoxin on MPO activity in a different degree in the tissues suggesting possible involvement of any mediator and/or mechanism which also causes neutrophil infiltration during inflammatory response at least in mesenteric artery. Moreover, ERK1/2 seems to be involved in the endotoxin-induced increase in total antioxidant capacity in mesenteric artery.

Apolipoprotein E polymorphism and lipoprotein compositions in normolipidaemic xanthelasma patients.

BACKGROUND: Apolipoprotein E (apoE) phenotypes and lipoprotein compositions in xanthelasma patients have been reported in different series. OBJECTIVE: To investigate the apoE polymorphism and lipoprotein compositions in xanthelasma patients by using rapid polymerase chain reaction, and searched for an association between apoE polymorphism and the lipoprotein levels in xanthelasma patients. DESIGN: ApoE polymorphism and the different types of serum lipoproteins were studied in 25 patients with xanthelasma and compared with 27 normal subjects. RESULTS: All of patients were found to be normolipidaemic. The patients had significantly higher concentrations of total cholesterol and apolipoprotein B, and lower concentrations of apolipoprotein A. There was no difference in serum triglyceride, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol concentrations. The distribution of apoE genotypes and alleles was the same in both groups. CONCLUSIONS: The apoB, apoA and cholesterol levels did show statistically significant differences in the direction of an increased risk of atherosclerosis. Patients with xanthelasma demonstrated slight differentiations in the apoE polymorphism and metabolism of lipoproteins that require further clarifications.

Effects of Nigella orientalis and N. segetalis fixed oils on blood biochemistry in rats.

Nigella orientalis and N. segetalis fixed oils were administered orally (1 mL/kg/day) to Wistar Kyoto rats for 4 weeks. The effects of the oils on biochemical parameters were compared with a control group that received distilled water under identical conditions. LDL-cholesterol level was decreased significantly in both oil groups while serum total cholesterol and VLDL-cholesterol were decreased significantly following administration of only N. orientalis fixed oil when compared with the control group. The HDL-cholesterol levels were increased significantly in both oil groups.N. orientalis fixed oil significantly reduced Aspartateaminotransferase (AST), Alkaline Phosphatase (ALP), bilirubin and urea levels in rats. There was an increase in the albumin, uric acid and mean corpuscular volume (MCV) concentrations, while the mean corpuscular hemoglobin concentration (MCHC) and RDW (red cell distribution width) levels decreased significantly. In N. segetalis fixed oil treated rats, the levels of ALP, Blood Urea Nitrogen (BUN), MCHC, RDW were decreased significantly, whereas a significant increase was found in albumin, fibrinogen, Hematocrit (HCT) and MCV levels. The effects of 4 weeks oral intake of N. orientalis and N. segetalis fixed oils on blood malondialdehyde (MDA) and total antioxidant status (TOS) were also investigated in rats. The study showed that the oils had no significant effect on MDA production. N. orientalis and N. segetalis fixed oils caused a significant increase in the total antioxidant status in rats.

CYP2C19 polymorphisms in patients with gastric and colorectal carcinoma.

BACKGROUND: It has been reported that up to 80% of human cancers arise as a consequence of environmental exposure and host susceptibility factors. Environmental carcinogens are predominantly metabolized by the cytochrome P450 (CYP) superfamily of drug- or xenobiotic-metabolizing enzymes. Genetic variations in these enzymes affect individuals' susceptibility to carcinogens. AIM OF THE STUDY: The aim of this study was to evaluate the relationship between CYP2C19 polymorphism and susceptibility to these cancers by means of CYP2C19 genotyping among Turkish subjects. METHODS: DNAof subjects were isolated from leukocytes by high pure template preparation kit (Roche Diagnostics, GmbH, Mannheim, Germany) and genotypes were detected by LightCycler CYP2C19 Mutation Detection Kit by real-time PCR with LightCycler instrument (Roche Diagnostics, cat. no. 3113914). RESULTS: Being male was associated with a 3.5-fold (OR: 4.27, CI: 2.27-8.05) and 4.27-fold (OR: 3.50, CI: 1.948-6.301) risk for colorectal and gastric carcinoma, respectively. The CYP2C19*3 heterozygote genotype was not found in either gastric or colorectal carcinoma patients. Although the frequency of CYP2C19*2 heterozygote genotype is high in patients with gastric and colorectal carcinoma, it is not significantly associated with cancer (OR: 1.79, CI: 0.829-3.865 and OR: 1.998, CI: 0.961-4.154, respectively). CONCLUSION: Although the frequency of CYP2C19*2 heterozygote genotype is high in our patients with gastric and colorectal carcinoma, there is no the relationship between CYP2C19 polymorphism and susceptibility to these cancer.

Nitric oxide reverses endotoxin-induced inflammatory hyperalgesia via inhibition of prostacyclin production in mice.

We examined whether nitric oxide (NO), derived from constitutive NO synthase (NOS) and/or inducible NOS (iNOS), could contribute to endotoxin-induced inflammatory hyperalgesia via interacting with nuclear factor-kappaB (NF-kappaB), inducible cyclooxygenase (COX-2) and/or polyADP-ribose synthase (PARS). Injection of endotoxin (10 mg kg(-1), i.p.) to mice elicited hyperalgesia, determined by hot plate test, which is prevented by NO precursor (L-arginine), cNOS/iNOS inhibitor (N(G)-nitro-L-arginine methyl ester; L-NAME), NF-kappaB inhibitor (N-acetylserotonin), COX inhibitor (indomethacin), COX-2 inhibitor (DFU) and PARS inhibitor (3-aminobenzamide). Endotoxin caused a decrease in serum nitrite levels prevented by N-acetylserotonin, L-arginine, indomethacin, DFU or 3-aminobenzamide. Endotoxin increased serum 6-keto-PGF(1alpha) levels diminished by L-arginine or aminoguanidine (iNOS inhibitor). L-Arginine, L-NAME, aminoguanidine, DFU or 3-aminobenzamide prevented endotoxin-induced decrease in heart, lungs, kidneys and brain nitrite and malonedialdehyde levels and myeloperoxidase activity. In conclusion, NO reverses endotoxin-induced inflammatory hyperalgesia via inhibition of prostacyclin production, and also contributes to the analgesic effect of NF-kappaB, COX or PARS inhibitors.

N-acetyltransferase 2 polymorphisms in patients with Behcet's disease.

It is possible that dietary, environmental factors and/or genetic polymorphisms in xenobiotic-metabolizing enzymes may contribute to the development of Behcet's disease. As N-acetyltransferase (NAT) 2 is an important xenobiotic-metabolizing enzyme and theoretically the nonacetylated xenobiotics may induce an autoimmune mechanism, the aim of the present study was to investigate whether the genetic polymorphism of NAT2 plays a role in susceptibility to Behcet's disease. Forty Behcet's disease patients and 82 control subjects were enrolled in the study. NAT2*5A, NAT2*6A, NAT27*A/B and NAT2*14A polymorphisms were detected by using real time PCR with LightCycler (Roche Diagnostics GmbH, Mannheim, Germany). The NAT2*5A and NAT2*6A mutant genotypes carried an increased risk of developing Behcet's disease [odds ratio (OR) = 66.29, 95% confidence interval (CI) = 8.21-535.33; and OR = 24; 95% CI = 2.04-304.98, respectively]. The NAT2*7A/B and NAT2*14A gene polymorphisms were not an increased risk for developing Behcet's disease. As a result of this study we conclude the NAT2 slow acetylator status may be a determinant in susceptibility to Behcet's disease. This finding may have implications for the theories of the pathogenesis of the disease as well as for therapeutic aspects.

Role of oxidative stress enzymes in open-angle glaucoma.

PURPOSE: To investigate the role of oxidative stress and lipid peroxidation in the pathogenesis of primary open-angle glaucoma (POAG). MATERIALS AND METHODS: The activities of myeloperoxidase (MPO), catalase (CAT), and the levels of plasma malondialdehyde (MDA) were measured in 40 (15 men and 25 women) patients with POAG and 60 (30 men and 30 women) healthy controls. RESULTS: There was no significant difference in the activities of CAT and MPO between the POAG patients and the controls. However, the plasma MDA level was significantly higher in patients than the controls. CONCLUSION: The results of this preliminary study suggest that the possible alterations of plasma MDA levels may be associated with the pathogenesis of POAG, but further research is needed to understand the role of oxidative damage in this important disorder of aging.

Plasma catalase activity and malondialdehyde level in patients with cataract.

PURPOSE: Oxidative mechanisms play a major role in the aetiology and pathogenesis of cataract, especially in age-related cataract. Our study aims to investigate systemic oxidant and antioxidant markers in cataract patients. METHODS: The activity of erythrocyte catalase and the level of malondialdehyde in plasma were measured in 40 patients with cataract and 60 healthy control subjects. The malondialdehyde level, as an index of lipid peroxidation, was determined by thiobarbitüric acid reaction according to Yagi. The determination of catalase activity was measured by a method that was defined by Beutler. Catalase enzyme activity and malondialdehyde level were evaluated to find out whether there was a significant difference in these variables. Analysis of variance was used by forming a general linear model that takes age and gender as the covariate. RESULTS: CAT activity was found to be 13 920.2 +/- 847.9 U/l in cataract patients and 16 061.3 +/- 1126.6 U/l in control subjects. CAT activity in cataract patients was significantly lower than the control subjects (P = 0.008). Plasma MDA level is significantly higher in patients with cataract 4.47 +/- 0.35 nmol/ml compared to the control subjects 2.94 +/- 0.26 nmol/ml (P = 0.0001). There was no significant difference between different cataract subgroups when erythrocyte CAT activities and plasma MDA levels were compared (P = 0.322, 0.062). CONCLUSION: This study shows that oxidant/antioxidant balances alter in the presence of cataract.

Apolipoprotein B gene polymorphisms in people in the east Mediterranean area of Turkey.

Point mutations in the receptor binding domain of low density lipoprotein may increase cholesterol levels in blood. Three mutations of Apo B-100 protein result in defective binding (Arg 3500 ----> [corrected] Gln, Arg 3500 ----> [corrected] Trp and Arg 3531 ----> [corrected] Cys). We estimated the frequency of Apo B point mutations (codon 3500) C9774T (Arg 3500 ----> [corrected] Trp) and G9775A (Arg 3500 ----> [corrected] Gln) in 179 atherosclerotic, 145 hyperlipidaemic individuals and 272 healthy individuals in the east Mediterranean region of Turkey. Lipid and lipoprotein levels were measured with routine biochemical analyser and Apo B mutation was detected using real-time PCR. Neither mutation was found. In this region, Apo B-100 protein mutations are rare and causes of hyperlipidaemia and atherosclerosis may therefore be unrelated to them.

Apolipoprotein B gene polymorphisms in people in the East Mediterranean area of Turkey

Point mutations in the receptor binding domain of low density lipoprotein may increase cholesterol levels in blood. Three mutations of Apo B-100 protein result in defective binding [Arg 3500 ----> [corrected] Gln, Arg 3500 ----> [corrected] Trp and Arg 3531 ----> [corrected] Cys]. We estimated the frequency of Apo B point mutations [codon 3500] C9774T [Arg 3500 ----> [corrected] Trp] and G9775A [Arg 3500 ----> [corrected] Gln] in 179 atherosclerotic, 145 hyperlipidaemic individuals and 272 healthy individuals in the east Mediterranean region of Turkey. Lipid and lipoprotein levels were measured with routine biochemical analyser and Apo B mutation was detected using real-time PCR. Neither mutation was found. In this region, Apo B-100 protein mutations are rare and causes of hyperlipidaemia and atherosclerosis may therefore be unrelated to them

Oxidant/antioxidant status in patients with recurrent aphthous stomatitis.

Recurrent aphthous stomatitis (RAS) is recognized as one of the most common oral mucosal diseases worldwide. The aim of this study was to determine the oxidant/antioxidant status in erythrocyte and plasma samples from patients with RAS in comparison with healthy controls. Twenty-two patients with RAS and 23 healthy controls were recruited. Superoxide dismutase, glutathione peroxidase (GSHPx) and catalase (CAT) activities, and malondialdehyde (MDA) and antioxidant potential (AOP) levels were measured in plasma and erythrocytes from patient with RAS and controls. We found decreased CAT and GSHPx activities and AOP levels in the erythrocytes, and decreased AOP and increased MDA plasma levels in patients with RAS in comparison with control subjects. In summary, this study demonstrated that enzymatic and nonenzymatic antioxidant defence systems are impaired in patients with RAS.

Effects of Daflon on oxidative stress induced by hindlimb ischemia/reperfusion.

The objective of this study was to investigate the effects of Daflon 500 mg on tissue damage in kidney after ischemia/reperfusion hindlimb, by assessing blood biochemical assay and histopathological analysis. Rats were given Daflon 80 mg x kg(-1) x day(-1) for 10 days. On 11th day of treatment, 4h ischemia followed by 4 h reperfusion period was performed on right hind limb of the rats. Control groups were given only arabic gum and were subjected to same ischemia/reperfusion period. At the end of reperfusion period, erythrocyte superoxide dismutase, Na(+)-K(+) ATPase and reduced glutathione levels were increased in the rats erythrocytes in Daflon group (P<0.01, for all). On the other hand, serum myeloperoxidase and malondialdehyde levels were significantly lower in the Daflon-received rats (P<0.01, for all). Histopathological studies demonstrated that, there was a prominent tubulointerstitial injury with loss of brush border and this degeneration was accompanied by segmental glomerular degeneration also for both control and Daflon group. Daflon-received group animals displayed significantly less periglomerular and perivascular leukocytic infiltration (P=0.015). These overall results suggest that Daflon contributes renal protection from hind limb ischemia/reperfusion injury in some degree, by decreasing systemic oxidative stress.

Effects of trimetazidine on tissue damage in kidney after hindlimb ischemia-reperfusion.

The objective of this study was to investigate the effects of trimetazidine (TMZ) on tissue damage in kidney after hindlimb ischemia-reperfusion (I/R), by assessing blood biochemical assay and histopathological analysis. Adult male Wistar rats were divided into two groups. TMZ 10 mg kg(-1)day(-1) was administrated twice a day for 10 days to the treatment group (group T, n=10). Sham group was given only 5% gum arabic (group S, n=10). On 11th day of treatment, 8h I/R period was performed on right hindlimb of the rats. At the end of reperfusion period, a 5 ml blood withdrawn from ascending aorta for biochemical assays and their right kidneys were harvested for histopathological examination. Superoxide dismutase, Na(+)-K(+) ATPase, and reduced glutathione levels were significantly increased in group T (P<0.001). On the other hand, myeloperoxidase and malondialdehyde levels were significantly less in group T than group S (P<0.001). Kidneys from the sham-operated group displayed intense leukocytic infiltration in histopathological examination. These overall results strongly suggested that TMZ contributes renal protection from hindlimb I/R injury by decreasing systemic oxidative stress.

The role of nitric oxide and lipid peroxidation in patients with Plasmodium vivax malaria.

In this study, we investigated the role of nitric oxide metabolism and lipid peroxidation in patients with P. vivax malaria. The levels of nitrite and nitrate were analyzed using a procedure based on the Griess reaction and malondialdehyde levels which index of lipid peroxidation was determined by thiobarbituric acid reaction. The levels of nitrite/nitrate and malondialdehyde in patients were higher than controls and found to be statistically significant (p < 0.001). We performed this study to determine whether nitric oxide and lipid peroxidation is produced during blood-stage P. vivax malaria. This present study shows that lipid peroxidation occurs in P. vivax malaria. The levels of nitric oxide are associated with lipid peroxidation in this disease.

The relationship between leptin and lipids in atherosclerosis.

BACKGROUND: This study aimed to examine the extent to which leptin, alone or in combination with other risk factors, may be an independent marker for myocardial infarction in a region with a high incidence of cardiovascular disease. METHODS AND RESULTS: Leptin levels were measured by the ELISA method, while plasma lipids and lipoproteins were measured by conventional methods. Leptin levels were significantly higher in the patient than in the control group. Serum total cholesterol, low-density lipoprotein, lipoprotein (a) and apolipoprotein B showed a significant correlation with leptin, while high-density lipoprotein showed an inverse relation. CONCLUSIONS: Our results suggest that leptin may be one factor operating in the metabolic alteration taking place during myocardial infarction, and is a possible risk factor.

Levels of malondialdehyde, glutathione and ascorbic acid in idiopathic thrombocytopaenic purpura.

BACKGROUND: Idiopathic thrombocytopaenic purpura (ITP) is an autoimmune disorder, which causes an acute or chronic thrombocytopenia, and may result in potentially life-threatening haemorrhage. Oxidative damage may be involved in the pathogenesis of autoimmune diseases. Antibodies to bind to membrane lipids and platelet destruction may play a role on lipid peroxidation in ITP. OBJECTIVES: To investigate the posible role of lipid peroxidation and antioxidants in patients with ITP. DESIGN: The levels of plasma and erythrocyte malondialdehyde (MDA), erythrocyte glutathione and ascorbic acid were analysed in patients with ITP. METHODS. The MDA levels were performed according to the method of Bidlack WR. Plasma MDA, erythrocyte glutathione and ascorbic acid levels were carried out according to the methods of Ohkawa H, Beutler E and Bauer JD, respectively. RESULTS: The erythrocyte and plasma MDA levels in patients with ITP were found to be 9.52+/-4.65, 3.03+/-1.44 (p<0.001) and in control group were found to be 2.49+/-0.57, 1.03+/-0.28 nmol/ml (p<0.001), respectively. Erythrocyte glutathione was found to be 3.71+/-0.82, 6.26+/-0.66 micromol/gr Hb (p<0.001). Ascorbic acid levels of these groups were 1.09+/-0.25, 1.70+/-0.33 mg/dl (p<0.001). CONCLUSION: The oxidative damage is involved in the pathogenesis of ITP. In patients with ITP, the platelet destruction and bleeding may play significant role on elevation of lipid peroxidation and reduction of antioxidant capacity. Further studies on oxidant and antioxidant status of ITP are also needed to confirm these results.

Serum L-carnitine levels and lipoprotein compositions in chronic viral hepatitis patients.

OBJECTIVES: The aim of this study was to evaluate the serum L-carnitine levels and its effect on lipoproteins in chronic viral hepatitis B or C patients. DESIGN AND METHODS: Blood samples were taken from 41 patients and 30 healthy subjects after 12 h fasting. RESULTS: Patients' serum L-carnitine levels (11.19 +/- 6.67 mg/L) (p < 0.0001) and hepatic enzyme activities (AST and ALT) (49.02 +/- 42.80 and 58.35 +/- 57.51 U/L) (p < 0.0005) were significantly higher than controls'. Serum total (3.85 +/- 0.82 mmol/L), LDL (2.08 +/- 0.76 mmol/L) and HDL (1.02 +/- 0.29 mmol/L) cholesterol levels were significantly lower in patients (p < 0.01). On the other hand triglyceride levels (1.65 +/- 0.85 mmol/L) were significantly higher in patients (p < 0.05). CONCLUSIONS: The higher L-carnitine levels of patients may result from the leakage of hepatic cellular carnitine. If there is a decreased hepatic cellular carnitine levels, this may affect the transport of acetyl moiety for cholesterol synthesis and alter lipoprotein composition. Further investigation is needed for hepatic tissue L-carnitine levels.