inhibitory effects of melatonin on vascular reactivity: possible role of vasoactive mediators

The aim of this study was to investigate the effect of melatonin [MEL] on isolated rabbit aortic rings and its role in the vascular reactivity to contractile agents, noradrenaline [NA] and phenylephrine [PHE], as well as the relaxant agents [acetylcholine and sodium nitroprusside]. In addition, the levels of nitric oxide [NO], cyclic guanosine monophosphate [cGMP], total calcium, lipid peroxides, superoxide dismutase [SOD] and glutathione [GSH] were also investigated in the tissue homogenates of rabbit aortic rings pre-incubated [20 min] in MEL with and without contractile agents. The result revealed that MEL has an endothelium dependent vaso-relaxant effect and potentiated significantly the vaso-relaxant effect of acetylcholine. Moreover, MEL [10-4M] had a significant inhibitory effect on the contractile responses of aortic rings to both NA and PHE. In comparison with the control tissue rings, the levels of lipid peroxides were significantly increased; while those of GSH and SOD activities were significantly decreased in the tissue homogenates of aortic rings pre-incubated [20 min] in NA or PHE. In addition, the levels of NO and cGMP were significantly lower in the tissue rings pretreated with NA and PHE, respectively. The levels of total calcium were significantly increased in only tissue rings pretreated with NA. The levels of lipid peroxides were significantly decreased; while those of GSH, NO, cGMP and SOD activities were significantly increased in tissue homogenates of aortic rings incubated [20 min] in MEL [10-4 M] in comparison with ring tissues incubated in NA or PHE alone. In aortic rings incubated In MEL + PHE, the levels of lipid peroxides were significantly lower; while those of GSH, cGMP and SOD activities were significantly higher than their levels in ring tissues incubated in PHE. In aortic rings incubated in MEL + NA, the levels of lipid peroxides and total calcium were significantly lower; while those of NO were significantly higher than their levels in ring tissues incubated in NA alone

Role of tumor necrosis factor-alpha, lipid peroxidation, nitric oxide and cyclic gaunosine monophosphate in lung cancer

Cytokines and lipid peroxidation can participate in the complicated process of carcinogenesis and tumor progression. In the present study, the serum levels of tumor necrosis factor-alpha [TNF-alpha], lipid peroxides [LPO], nitric oxide [NO] and cyclic guanosine monophosphate [cGMP] were measured in 32 patients with lung cancer and in 30 healthy control subjects. The levels of TNF-alpha and cGMP were measured using ELISA and the levels of LPO and NO were measured using colorimetric methods. The levels of TNF-alpha, LPO, NO and cGMP were significantly higher in lung cancer patients than in the control group. In patients with lung cancer, a significant positive correlation was found between LPO and each of TNF-alpha and NO. According to the clinical stage and histological type, the serum levels of TNF-alpha, LPO and NO were significantly elevated in the advanced stage and non small cell lung cancer compared with the limited lung cancer. The serum levels of cGMP were higher in advanced than limited lung cancer. A significant positive correlation between NO and cGMP was found in patients with advanced lung cancer. In conclusion, the elevation of serum levels of TNF-alpha, LPO and NO in patient with lung cancer may have a prognostic value, being associated with a worse prognosis. The NO/cGMP system may play an important role in the advanced lung cancer

Free radicals, total antioxidant status and interleukin-6 in seminal plasma of fertile and infertile men.

This work aimed to assess total antioxidant status, lipid peroxides [LPO], nitric oxide [NO] and interleukin-6 [IL-6] in seminal plasma of infertile men [n = 45] compared with fertile men [controls, n = 30]. The infertile men included asthenozoospermic [n = 17], asthenoteratozoospermic [n = 25] and oligozoospermic patients [n = 3]. The semen samples from fertile men showed antioxidant capacity at a higher value than equivalent samples from infertile men. Moreover, the inverse relationship between antioxidant capacity and lipid peroxidation in seminal plasma strongly suggested that impaired defenses play an important role in infertile disorders. Furthermore, the increased oxidative stress observed in infertile men may modulate the level of IL-6

Oxidative stress in seminal plasma of subfertile men with varicocele

To compare the oxidative stress in the seminal plasma of subfertile patients with and without varicocele. The free radicals and antioxidants were measured in seminal plasma of subfertile men with [n= 48] and without varicocele [n=50]: lipid peroxidation [LPO], nitric oxide [NO], superoxide dismutase [SOD], glutathione peroxidase [GSH-Px], glutathione reductase [GSH-R], total thiols [TT] and ceruloplasmin [CP]. Samples from patients with varicocele had significantly higher levels of LPO and NO in comparison with subfertile men without varicocele [P<0.001]. In addition, seminal plasma of patients with varicocele showed significantly lower activities of GSH-Px and GSH-R and lower levels of [TT] [P<0.001]. No significant differences in the activities of SOD enzyme and the levels of CP were found when the two groups were compared. Also, no significant differences in these biochemical variables were detected when varicocele was classified according to its grade or laterality. LPO levels correlated negatively with sperm motility [grade A] [r = -0.26, P<0.05], GSH-Px [r = -0.30, P< 0.05] and TT [r= -0.36, P<0.01] while correlated positively with the number of pus cells in semen [r= 0.35, P<0.01]. Furthermore, NO levels correlated positively with the percent of sperms with abnormal morphology [r= 0.34, P< 0.01] while correlated negatively with GSH-R [r=-0.38, P< 0.01]. Oxidative stress may be an important etiologic factor in the pathogenesis of infertility in patients with varicocele compared to other subfertile men. The therapeutic antioxidants and drugs that reduce NO levels may be implicated in the varicocele treatment

Serum interleukin-1P, inerleukin-6, nitric oxide and acute phase reactant in scorpion envenomated children

This study included 38 scorpion envenomated children with ages ranged between 1.5-12 years as well as 13 apparently healthy age matched controls. All victims were admitted to the Pediatric Intensive Care Unit [PICU]. The victims and controls were subjected to complete clinical history and examination, assessment of the nutritional status by anthropometric measurements and full blood count. The evaluation of the serum levels of interleukin-1 beta [IL-1 beta], interleukin-6 [IL-6], nitric oxide [NO] and alpha 1 antitrypsin [alpha 1-AT] was performed once for the controls and twice for the victims; the first sample on admission and the second sample was obtained 24 hours later. It was concluded that the obtained data revealed that cytokines are involved in the pathogenesis of scorpion envenomation and correlated with the severity of envenomation