Oxidative stress in dengue infection has been suggested. This study was carried out to explore the plasma protein oxidation and its sialic acid content in dengue infection. Thirty-two dengue hemorrhagic fever (DHF), 25 dengue shock syndrome (DSS), 29 dengue fever (DF), and 63 healthy controls were included in this study. The extent of carbonylation, sulphydryl content, and desialylation of plasma protein was estimated in acute phase sample. Significantly higher levels of protein carbonyls and lower levels of sialic acid and sulphydryl groups were found in DHF and DSS compared with DF using one-way analysis of variance. Regression analysis showed that desialylation is dependent on protein carbonyls in DHF/DSS. This study indicates that, in dengue infection, plasma proteins undergo increased levels of desialylation, which can be attributed to the oxidative stress. Future studies on sialylation status of endothelium and platelets can show light into the pathogenesis of the dengue infection.

OBJECTIVES: Oxidative stress in dengue viral infection has been suggested and severity of it was found to be associated with progress of illness. Hence assessing oxidative stress mediated changes in plasma proteins can be an early biomarker for prediction of severe dengue infection. DESIGN AND METHODS: Thirty two dengue hemorrhagic fever (DHF), 21 dengue shock syndrome (DSS), 27 dengue fever (DF) and 63 age and sex matched controls, were included in this study. Blood samples were collected on the 3rd day of fever. Protein carbonylation (PCOs) and protein-bound sulphydryl (PBSH) group levels were determined by spectrophotometric method and analyzed as predictor of dengue hemorrhagic fever and dengue shock syndrome. RESULTS: About 80-84% of cases presented with no signs of DHF/DSS at the time of sampling. Dengue infected individuals had significantly elevated PCOs and low PBSH group levels than the controls. Using one-way ANOVA we found a significant difference with high PCOs and low PBSH group levels between DHF and DSS when compared with DF (P<0.001). However, no difference was observed in PBSH group levels between DHF and DSS. A significant difference in PCOs to PBSH ratio was observed among DF, DHF and DSS (P<0.001). Linear regression analysis revealed that duration of hospitalization is dependent on PCOs and PBSH group levels. Receiver operator curve (ROC) analysis indicated that 5.22nmol/mg protein PCOs; 1.08 PCOs to PBSH group levels ratio were optimal cutoff value for predicting DHF with sensitivity and specificity of 87.5% and 74.1%; 96.9% and 81.5%, respectively. For DSS prediction, 6.13nmol/mg protein PCOs; 1.16 PCOs to PBSH group levels ratio were found as effective cutoff with sensitivity and specificity of 81% and 71.9%; 95.2% and 56.2%, respectively. CONCLUSION: Oxidative stress has been observed to develop since early days of onset of dengue infection. Plasma PCOs, PCOs to PBSH group ratio were found to very well predict DHF/DSS.

An association between viral diseases and increased oxidative stress has been suggested. The time course of serum levels of total antioxidant status (TAS), peroxidation potential (PP), glutathione (GSH), lipid peroxidation measured as hydroperoxides, and malondyaldehyde and 4-hydroxyalkenals (MDA + 4-HDA), as well as antioxidant enzymatic activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx), were measured in 22 serologically confirmed dengue patients. Most of the patients had dengue fever and three of them had dengue hemorrhagic fever. The redox parameters were compared with those of age- and sex- matched controls. No significant difference was observed for levels of GSH and TAS between patients and controls. Levels of PP, MDA + 4-HDA, and SOD were significantly higher. Levels of GPx and total hydroperoxides were significantly lower in patients in comparison with controls. These findings suggest that the alteration in redox status could result of increased oxidative stress and it may play a role in the pathogenesis of the disease.

The aim of this work was to describe the factors influencing the levels of three antioxidant markers -total antioxidant status, erythrocyte copper/zinc superoxide dismutase (SOD), whole-blood selenium glutathione peroxidase--and to establish their reference intervals in supposedly healthy subjects. The studied population included 463 subjects, i.e., 223 adults and 140 children aged 20 to 65 and 4 to 19 years, respectively. The effect of factors such as age, gender, body mass index, alcohol and tobacco consumption, menopause, drug intake, trace elements, transferrin, ferritin, albumin, bilirubin, haptoglobin, total proteins, uric acid, haemoglobin, and mean corpuscular volume of erythrocytes have been studied for the three antioxidant markers. Total antioxidant status (TAS) was higher in men than in women whatever the age (p < 0.001). Albumin and uric acid in men, women and girls, and total proteins in boys were significant determinants of TAS levels. Mean corpuscular volume of erythrocytes were negatively and significantly associated with SOD activity in men and in women (p < 0.01) but not in children. Among the studied determinants, none were found to influence the selenium glutathione peroxidase activity in the four groups. Reference intervals including the 90% confidence intervals were established by age and sex for the three antioxidant markers.

Although they are considered as destructive agents, free radicals can sometimes become useful. Their presence is intimately coupled with the activity of certain hemal oxydases which insert an atom of oxygen into their substrate by a stereospecific radical mecanism. The cytochromes P450 and the enzymes of the eicosanoide metabolism are some examples. The free radicals can act as second cellular messengers, especially to modulate the metabolism of arachidonic acid and the prostaglandin tract or to infer a myorelaxation. They can even play the role of neurotransmitters such as azote monoxyde. The activation of phagocytes, which is an essential event in the inflammatory reaction, integrates these notions at several levels: in the mechanisms of bacterial death, in the spread of the inflammatory reaction and in the alteration of the extra-cellular matrix. The inflammatory reaction is initiated by interactions between vascular endothelium, platelets and leukocytes including signal exchanges, adhesion molecule expression and secretion of chimiotactic mediators. Activation of vascular endothelium is a key event in the initiation of the phenomenon. The cells intervening in the precocious inflammatory phase were tissular mastocytes and platelet-liberating mediators (histamine) and neutrophile cells responsible for vascular injuries induced by oxygen free radicals and nitric oxide. Reactive oxygen intermediates play a critical role, primarily to limit tissue damage and prevent or inhibit infection, secondary to enhancing and prolonging reaction. The monocytes and platelets liberate cytokines early, which appears to be important in activation and production of an inflammatory response. In fact, cytokines, especially TNF alpha and IL-1, induce synthesis and secretion endothelial adhesion molecules such as ICAM-1, VCAM-1 and E-selectin, which have been demonstrated to mediate leukocyte recruitment to sites of inflammation. The cytokines also activate the fibroblasts and endothelial cells that produce, among others, free radicals and other chimiotactic cytokines of which some (IL-8 and related) can induce neutrophil degranulation and stimulate oxidative stress and formation of free radicals. Furthermore, endothelial cells have been shown to make use of a broad repertoire of cytokines including IL-1, IL-6, IL-8, MCP-1 and gro/MGSA, which may be secreted during an inflammatory response and exercise pro-inflammatory functions. Under the influence of the inflammatory mediators, other enzymes are also activated. The inducible isoforms of cyclo-oxygenase (COX-2) and nitric oxide synthase (iNOS) play an important role in inflammatory reactions via the production respectively of prostaglandins and nitric oxide. The induction of cell adhesion molecules (ICAM-1, VCAM-1 and E-selectin), cytokines, acute phase proteins, growth factors, COX-2 and iNOS expression is mediated by the activation of transcriptional factors, especially the nuclear factor kappa B (NF-kappa B). The NF-kappa B system is essentially involved in immediate early expression of various immunoregulatory genes and has been demonstrated to represent an important regulatory system of endothelial activation. The target genes for NF-kappa B comprise a growing list of genes intrinsically linked to a coordinated inflammatory response. The NF-kappa B is a heterodimer composed of two subunits (p65 and p50). In non-stimulated cells, NF-kappa B resides in the cytoplasm as an inactive complex bound to its inhibitor, I kappa B. Upon stimulation with various agents including cytokines, mitogenes, viruses and reactive oxygen intermediates, I kappa B dissociates from the NF-kappa B-I kappa B complex and translocates to the nucleus, binding with high affinity to specific sites in the promoter regions of target genes and stimulating their transcription. In the case of any weakness of this anti-oxidizing defence or any over-production of radical species, a state of oxidative stress occurs.(ABSTRACT TRUNC

The clinic table of serious scorpionic envenimation is dominated by cardiovascular and pulmonary perturbations. The physiopathology of cardiac failure in man as well as at animal is again badly elucidated. The aim of our study has consisted in evaluating the hemodynamic variations of the Rat poisoned by the venom of the Buthus occitanus scorpion and to contribute through the analyse of plasmatic concentrations of catecholamines and by an histomorphometric study of muscular microcirculation to explain the mechanism of the hemodynamic perturbations and cardiac failure. 51 rats corresponding to 9 groups (witness and poisoned) have been used. The venom of the scorpion Buthus occitanus has been administrated at 850 micrograms/kg. Two groups have been served for hemodynamic study, three groups for the dosage of catecholamines and four groups for histomorphometric study. It has been observed a biphasic variation of arterial pressure and cardiac frequency after venom injection. Four minutes after envenimation, the plasmatic level of catecholamines was strongly higher in the poisoned according to the witness one. Histomorphometric study of muscular skeletal microcirculation has shown a decrease of relative vascular volume contemporary with the increase of plasmatic catecholamines concentration and the peak of arteriel pressure appeared just after envenimation. 10 and 20 minutes after envenimation, the relative vascular volume has significantly increased as well as that interstitium according to witness lot. These hemodynamic perturbations can be attributed to the important dump in catecholamines. This hyperadrenergy was contemporary with decrease of relative muscular vascular volume. This decrease would be explained by a constriction of vessels. On the other hand, the second increase of the vascular relative volume suggests the possibility of development of venous stasis at the muscular microcirculation. It would be induced by a cardiac failure and/or the effect of vasoplegic mediators being able to entail an interstitial oedema in the muscular skeletal that would led to increase the relative interstitial volume observed in this study.

Aplastic anaemia is a potentially fatal haematopoietic disorder whose aetiology is not yet clarified. In our preliminary study we have introduced cyclosporin in the aplastic anaemia treatment to evaluate its effect on the disease evolution. Ten aplastic anaemia patients, mean age 33.33 +/- 20.01 years, were treated with cyclosporine (9 +/- 2.35 mg/kg/d), prednisolone (0.5 mg/kg/d) and androgens (1 mg/kg/d). The prednisolone was always combined with cyclosporine. The androgens were administered concomitantly with the cyclosporine or alternately. Seven patients responded to the treatment after a median remission delay of 6 weeks (2-12 weeks). They became independent of blood requirements at a median of 36 weeks (8-108 weeks); the three other patients died during the first trimester without showing any improvement. Among the seven responders, two relapsed early and transiently. The rate of actuarial survival was 70 per cent. The median duration of survival was 10.5 months. The side effects observed included one case of malignant lymphoma, six cases of liver toxicity and five cases of kidney toxicity. This toxicity was reversible after dose adjustment of the cyclosporine. In our study, the introduction of cyclosporin in the aplastic anaemia treatment resulted in improved therapeutic response. Androgens should be used to maintain the haematologic response. This therapeutic protocol associated with drug monitoring seems promising and the side effects should not limit its use because of the severity of the underlying disease.

The aim of the current study is to investigate the therapeutic and preventive effects of 1alpha, 25dihydroxyvitaminD3 (1,25 (OH)2 D3) and Afuga iva (AI) extract on diabetes toxicity in rats testes. Thus diabetic rats were treated with 1alpha, 25dihydroxyvitaminD3 or Ajuga iva extract as both therapeutic and preventive treatments on diabetes toxicity in rats testes. Our results showed that diabetes induced a decrease in testosterone and 17beta-estradiol levels in testes and plasma. Besides, a fall in testicular antioxidant capacity appeared by a decrease in both antioxidant (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities) and nonenzymatic antioxidant (copper (Cu), magnesium (Mg) and iron (Fe) levels). All theses changes enhanced testicular toxicity (increase in testicular aspartate amino transaminase (AST), alanine amino transaminase (ALT), lactate dehydrogenase (LDH) activities and the lipid peroxidation and triglyceride (TG) levels). In addition, a decrease in testicular total cholesterol (TCh) level was observed in diabetic rats testes. All the changes lead to a decrease in the total number and mobility of epididymal spermatozoa. The administration of 1alpha,25dihydroxyvitaminD3 and Ajuga iva extract three weeks before and after diabetes induction interfered and prevented diabetes toxicity in the reproductive system. 1,25 (OH)2 D3 and Ajuga iva extract blunted all changes observed in diabetic rats. To sum up, the data suggested that 1,25 (OH)2 D3 and Ajuga iva extract have a protective effect on alloxan-induced damage in reproductive system by enhancing the testosterone and 17beta-estradiol levels, consequently protecting from oxidative stress, cellular toxicity and maintaining the number and motility of spermatozoids.

The puffer fish Lagocephalus lagocephalus represents serious public health problems in the world. The relative toxicity of each organ (liver and flesh) was determined by the relation dose-death time "mouse bioassay." The average liver toxicity of the puffer fish was the highest when compared with flesh giving 14.32 and 10.88 MU/g, respectively. A mouse unit is the amount of toxin (extract of fish organ) that kills a 20 g male mouse in 30 min after intraperitoneal injection. One mouse unit is equivalent to 0.22 microg of TTX. For the rat bioassay tests, Wistar rats were daily i.p. injected, for 10 d, with extracts of liver (LT) or flesh (FT)(muscles + skin) of L. lagocephalus. Control rats received injection of NaCl (0.9%). During the experiment, a significant reduction in red blood cell number (RBC), hemoglobin (HGB) concentration, and hematocrit (HCT) was observed essentially after 10 d of treatment in the FT and LT-exposed groups. Consequently, treatment led to severe anemia and hemolytic action as indicated by a significant reduction in the total number of erythrocytes. In fact, our study revealed a significant increase in erythrocyte lipid peroxidation (LPO) in FT and LT groups compared with controls after experimental exposure. The flesh and liver tissue extracts also altered antioxidative enzymes activities: catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). Histopathological alterations in the spleen occurred exclusively at the end of treatment. We marked also an increase in reticulo-endothelial cells, which led to remove damaged erythrocytes.

1. Severe cases of scorpion envenomation (SE) generally show both respiratory and cardiocirculatory dysfunction. However, the pathophysiology of SE remains controversial. In the present study, we tried to explain the pathophysiology of the haemodynamic perturbations and cardiac failure in rats poisoned by the venom of Buthus occitanus tunetanus through a histomorphometric study of myocardial and muscular skeletal microcirculation and analysis of the oxidative stress state in order to evaluate the implication of the inflammatory process in the pathogenesis of SE. 2. Experiments were performed on 96 rats divided into 16 groups (n = 6 in each group). Two groups were used to determine the optimum conditions of venom administration and times when to measure haemodynamic parameters. The B. occitanus tunetanus venom was administered at a dose of 800 microg/kg and tissues were removed 5 and 20 min after envenomation. Six groups were used for histomorphometric study: two control groups, two poisoned groups an two melatonin-pretreated and poisoned groups. The histomorphometric study was performed on isolated hearts and skeletal muscles. The final eight groups of rats (two control groups, two envenomated groups, two control groups pretreated with melatonin and two groups pretreated and envenomated) were used to investigate the state of tissue oxidative stress during SE and to evaluate the anti-oxidant effect of melatonin on rats poisoned with B. occitanus tunetanus venom. This study was based on the determination of tissue malondialdehyde in isolated organs as an indicator of thiobarbituric acid-reactive substances (TBARS). Melatonin was injected at a dose of 5 mg/kg, i.v., 15 min before the administration of serum or venom. Data were compared using analysis of variance and Tukey's test for multiple pair-wise comparisons. 3. Five minutes after venom injection, a significant reduction in the mean relative volume of venules and arterioles in the heart and skeletal muscles of poisoned rats was noted. Twenty minutes after venom injection, these volumes were significantly increased in the heart and skeletal muscles of poisoned rats. Pretreatment of envenomated rats with melatonin resulted in a significant decrease in the mean relative volume of the venules and arterioles in the heart and skeletal muscles 5 and 20 min after venom injection compared with untreated envenomated rats. Investigation of the oxidative stress state showed a highly significant increase in TBARS in poisoned rats compared with control groups 5 and 20 min after venom injection. Melatonin pretreatment of rats poisoned with B. occitanus tunetanus venom resulted in an important and highly significant reduction of TBARS compared with untreated envenomated rats. 4. It appears from the results of the present study that administration of B. occitanus tunetanus venom engendered an excessive myocardial and skeletal muscular vasoconstriction attributed to massive catecholamine release followed by arteriolar and venular vasodilatation. This venous stasis at the muscular microcirculation could be due to myocardiac failure. However, the concomitant presence of arteriolar vasodilatation suggests an inflammatory process in the pathophysiology of SE. This process was suggested by the genesis of a state of oxidative stress in relation to the important lipoperoxidation, which was inhibited by administration of the anti-oxidant melatonin. Thus, melatonin pretreatment seemed to accentuate the first phase of vascular reactivity in envenomed rats and inhibit the second vasodilator phase observed 20 min after administration of the venom.

INTRODUCTION: The chronic kidney failure is a source of dyslipidemia and accelerated atherosclerosis. No changes in the lipoprotein profile could be reversed by dialysis. OBJECTIVE: Our aim was to study the lipid disturbances characteristics in end stage renal disease in order to assess their theorical atherogenic potential. SUBJECTS AND METHODS: The patient population consisted of 36 patients on maintenance haemodialysis. Matched control subjects were recruited among apparently healthy normolipidemic Tunisians. Total cholesterol, triglycerides, high-density-lipoprotein cholesterol, low-density-lipoprotein cholesterol, apolipoprotein AI and apolipoprotein B concentrations were measured. RESULTS: The triglycerides levels were significantly higher in patient group, unlike the high-density-lipoprotein cholesterol and apolipoprotein AI levels that were significantly reduced. We saw no increase in the levels of low-density-lipoprotein cholesterol and apolipoprotein B. The low-density-lipoprotein cholesterol/high-density-lipoprotein cholesterol ratio result wasn't helpful in the evaluation of the atherogenic risk. CONCLUSION: We confirm the quantitative lipid disorders associated with maintenance haemodialysis. The assessment of cardiovascular risk on the basis of these disorders seems difficult.

Numerous studies have reported beneficial effects of antioxidant drugs on semen quality, but there is no well-defined therapeutical protocol in male infertility. This study aimed to test the effects of vitamin E and selenium supplementation on lipid peroxidation and on sperm parameters. The study included 54 voluntary and infertile men who produced semen samples for spermiogram and for spectrophotometric measurement of a lipid peroxidation marker, the malondialdehyde (MDA), and produced blood samples for high-performance liquid chromatography assessment of serum vitamin E level. The trial was randomized and open. Twenty-eight men were supplemented daily by vitamin E (400 mg) and selenium (225 microg), during 3 months. The remaining 26 patients received vitamin B (4,5 g/day) for the same duration. Only 20 patients achieved their treatment and returned for control analysis. MDA concentrations in sperm were much less than in seminal plasma and motility and viability were inversely correlated with semen MDA levels. In contrast to vitamin B supplementation, vitamin E and selenium supplementation produced a significant decrease in MDA concentrations and an improvement of sperm motility. The results confirm the protective and beneficial effects of vitamin E and selenium on semen quality and advocate their use in male infertility treatment.

The second (bi2) intron of the mitochondrial cyt b gene from Saccharomyces capensis encodes a bifunctional protein which acts both as a maturase, promoting intron splicing, and as a homing-endonuclease, I-ScaI, promoting intron mobility. In this work we isolated and characterized revertants from a respiratory-deficient mutant in which both functions of the protein have been lost. Intragenic revertants resulted mainly from monosubstitutions in the mutated codon and in one case from a distant second site mutation. All novel variants of the S. capensis bi2 intron-encoded protein are competent for the maturase activity but only two of them can partially complement the homing function.

The scope of this work was to investigate the nature, chronology and mechanisms of the cardiovascular disorders induced by scorpion envenomation. Anaesthetized rats were instrumented for measurement of cardiac output (CO), renal (RBF) and muscular (HBF) blood flows (pulsed Doppler flowmetry), blood pressure, heart rate and dP/dt. Buthus occitanus venom (BO) was administered intravenously in the absence/presence of different pre-treatments. BO dose-dependently (150-300 microg/kg) increased blood pressure, dP/dt, total peripheral (TPR), renal (RVR) and muscular (HVR) vascular resistances, and decreased CO, RBF and HBF. Recovery occurred after 150 but not after 300 microg/kg. BO, 600 microg/kg, produced qualitatively similar effects but arrhythmias developed and mortality increased. Pre-treatment with phentolamine prevented the rises in TPR, RVR, HVR and blood pressure and the decreases in CO, RBF and HBF induced by BO, 300 microg/kg. Pre-treatment with propranolol prevented the rise in dP/dt and the occurrence of arrhythmias and limited the rise in RVR and the drop in RBF induced by BO, 300 microg/kg. Phentolamine, propranolol and their combination also prevented BO, 600 microg/kg-induced mortality. Other pre-treatments (bosentan, losartan, diltiazem, mepyramine) were almost ineffective vs. BO effects. Finally, BO, 300 microg/kg, induced a 30-40-fold increase in plasma epinephrine and norepinephrine levels, but no change in plasma endothelin-1 levels. Thus in anaesthetized rats, the pattern of the cardiac and systemic and regional haemodynamic effects of BO is typically that of and results from catecholamine outpouring-induced alpha- and beta-adrenoceptor stimulation.

In nanotoxicology the question arises whether high aspect ratio materials should be regarded as potentially pathogenic like asbestos, merely on the base of their biopersistence and length to diameter ratio. A higher pathogenicity of long asbestos fibers is associated to their slower clearance and frustrated phagocytosis. In the past decades, two amosite fibers were prepared and studied to confirm the role of fiber length in asbestos toxicity. Long fiber amosite (LFA) and short fiber amosite (SFA) have here been revisited, to check differences in their surface properties, known to modulate the biological responses elicited. We report:(i) micromorphology (abundance of exposed cylindrical vs. truncated surfaces;(ii) surface reactivity (oxidation and coordination state of surface iron, free radical generation and oxidizing potential);(iii) activation of nitric oxide (NO) synthase in lung epithelial cells, as representative of an inflammatory cell response. LFA shows a higher free radical yield, stimulates, more than SFA, NO production by cells and reacts with ascorbic acid, thus depriving the lung lining layer of its antioxidant defenses. The higher activity of LFA than SFA is ascribed to the presence of Fe(2+) ions poorly coordinated to the surface. SFA shows only a large number of loosely bound Fe(3+) ions, pristine Fe(2+) ions having been oxidized during the grinding process converting LFA into SFA. Several factors determine a higher toxicity of LFA than SFA, beside length. The lesson from asbestos indicates that other features besides aspect ratio contribute to the pathogenic potential of a fiber type. All these aspects should be considered when predicting the possible hazard associated to any new fibrous material proposed to the market, let alone nanofibers.

According to the "free radical theory" of aging, normal aging occurs as the result of tissue damages inflicted by reactive oxygen species (ROS). ROS are known to induce cellular senescence, and senescent cells are believed to contribute to organismal aging. The molecular mechanisms that mediate the cellular response to oxidants remain to be fully identified. We have shown that oxidative stress induces cellular senescence through activation of the caveolin-1 promoter and upregulation of caveolin-1 protein expression. Here, we describe how reactive oxygen species activate the caveolin-1 promoter and how the signaling may be assayed. These approaches provide insight into the functional role of caveolin-1 and potentially allow the identification of novel ROS-regulated genes that are part of the signaling machinery regulating cellular senescence/aging.

In the presence of exciting light, iron and reductants, the singlet oxygen ((1)O2)-generating sensitizer protoporphyrin IX (PpIX) induces free radical lipid peroxidation in membranes, but gradually degrades in the process. We postulated that NO, acting as a chain-breaking antioxidant, would protect PpIX against degradation and consequently prolong its ability to produce (1)O2. This idea was tested by irradiating PpIX- containing liposomes (LUVs) in the presence of iron and ascorbate, and monitoring the cholesterol (Ch) hydroperoxides 5alpha-OOH and 7alpha/beta-OOH as respective (1)O2 and free radical reporters. 5alpha-OOH accumulation, initially linear with light fluence, slowed progressively after prolonged irradiation, whereas 7alpha/beta-OOH accumulation only accelerated after an initial lag. The active, but not spent, NO donor SPNO (0.4 mM) virtually abolished 7alpha/beta-OOH buildup as well as 5alpha-OOH slowdown. Increasing membrane phospholipid unsaturation hastened the onset of rapid chain peroxidation and 5alpha-OOH slowdown. Accompanying the 5alpha-OOH effect was a steady decrease in (1)O2 quantum yield and PpIX fluorescence at 630 nm, both of which were inhibited by NO. An NO-inhibitable decay of PpIX fluorescence was also observed during dark incubation of 5alpha-OOH-bearing LUVs with iron/ascorbate, confirming a link between chain peroxidation and PpIX loss. By protecting PpIX in irradiated membranes, NO might select for and prolong purely (1)O2-mediated damage. Supporting this was our observation that (1)O2-mediated photoinactivation of a non-membrane target, lactate dehydrogenase, slowed concurrently with 5beta-OOH accumulation and that SPNO prevented this. Thus, NO not only protected membrane lipids against PpIX-sensitized free radical damage, but PpIX itself, thereby extending its (1)O2-generating lifetime. Consistent findings were obtained using porphyrin-sensitized COH-BR1 cells. These previously unrecognized effects of NO could have important bearing on 5- aminolevulinate-based photodynamic therapy in which PpIX is metabolically deposited in tumor cells.

In the presence of exciting light, iron and reductants, the singlet oxygen (1O2)-generating sensitizer protoporphyrin IX (PpIX) induces free radical lipid peroxidation in membranes, but gradually degrades in the process. We postulated that NO, acting as a chain-breaking antioxidant, would protect PpIX against degradation and consequently prolong its ability to produce 1O2. This idea was tested by irradiating PpIX-containing liposomes (LUVs) in the presence of iron and ascorbate, and monitoring the cholesterol hydroperoxides 5alpha-OOH and 7alpha/beta-OOH as respective 1O2 and free radical reporters. 5alpha-OOH accumulation, initially linear with light fluence, slowed progressively after prolonged irradiation, whereas 7alpha/beta-OOH accumulation only accelerated after an initial lag. The active, but not spent, NO donor spermine NONOate (0.4 mM) virtually abolished 7alpha/beta-OOH buildup as well as 5alpha-OOH slowdown. Increasing membrane phospholipid unsaturation hastened the onset of rapid chain peroxidation and 5alpha-OOH slowdown. Accompanying the 5alpha-OOH effect was a steady decrease in 1O2 quantum yield and PpIX fluorescence at 632 nm, both of which were inhibited by NO. An NO-inhibitable decay of PpIX fluorescence was also observed during dark incubation of 5alpha-OOH-bearing LUVs with iron and ascorbate, confirming a link between chain peroxidation and PpIX loss. By protecting PpIX in irradiated membranes, NO might select for and prolong purely 1O2-mediated damage. Supporting this was our observation that 1O2-mediated photoinactivation of a nonmembrane target, lactate dehydrogenase, slowed concurrently with 5alpha-OOH accumulation and that spermine NONOate prevented this. Thus, NO not only protected membrane lipids against PpIX-sensitized free radical damage, but PpIX itself, thereby extending its 1O2-generating lifetime. Consistent findings were obtained using porphyrin-sensitized COH-BR1 cells. These previously unrecognized effects of NO could have important bearing on 5-aminolevulinate-based photodynamic therapy in which PpIX is metabolically deposited in tumor cells.

An improved antioxidant status (overthreshold plasma values of essential antioxidants) minimizes the oxidative damage. The levels of antioxidant vitamins C and E,,,antioxidant" trace elements selenium, zinc, copper and iron were measured in two groups of adults with different nutritional habits--alternative (vegetarians; n=110) and traditional (mixed diet, control, n=101). The prevalence of iron and zinc deficiencies was found in the alternative group (20% vs 11%--iron, 13% vs 9%--zinc) as a consequence of higher intake of plant trace element absorption inhibitors. As opposed to the latter, the control group had higher findings of iron and copper levels over the optimal range (18% vs 8%--iron, 11% vs 2%--copper). The subjects on mixed diet was showed a significant negative linear correlation between serum zinc and iron levels. This favourable relationship means a decrease in Fenton reaction by indirect zinc effect. Average plasma values of vitamin C, vitamin C/vitamin E, vitamin E/ cholesterol (LDL protection), vitamin E/triacylglycerols (polyunsaturated fatty acid protection) in vegetarians are over the threshold with high number of individual overthreshold values (94% vs 17%--vitamin C, 100% vs 58%--vitamin C/vitamin E, 89% vs 68%--vitamin E/cholesterol, 100% vs 64%--vitamin E/triacylglycerols). Homocysteine levels in vegetarians (36% atherogenic levels) correlate significantly inversely to vitamin C levels, the fact of which means a positive vitamin C effect in free radical remove also in hyperhomocysteinemia. Plant food is a rich source of antioxidants. A correct vegetarian nutrition or optimized mixed diets with regular and frequent consumption of protective food commodities may be an effective contribution to the age-related chronic degenerative disease prevention.(Tab. 2, Fig. 2, Ref. 31.).

The biological significance of singlet oxygen (1O2), an electronically excited species of oxygen, has been realized only in the last two decades. This was mainly due to the lack of proper methodology to generate this reactive oxygen species (ROS) in pure form and its reactions with biological molecules. Recent studies, using newly developed detection methods, show that 1O2 being generated in many biological systems, can significantly and quite often adversely alter several crucial biomolecules including DNA, proteins and lipids with undesirable consequences including cytotoxicity and/or disesase development. The reactions of 1O2 with the biological molecules are rather specific, as compared to other ROS. There are various compounds, mainly derived from natural sources that offer protection against damage induced by 1O2. Among the antioxidants carotenoids are the most effective singlet oxygen quenchers followed by tocopherols and others. The same reactive species if generated specifically in diseased states such as cancer can lead to the cure of the disease, and this principle is utilized in the newly developing modality of cancer treatment namely photodynamic therapy. Singlet oxygen, in low concentrations can also act as signaling molecule with several biological implications. This review clearly brings out the biological significance of 1O2.

The level of trace elements such as Zn, Cu and Fe in testicular tissue is an indication of the condition of the tissue as these elements take over important tasks. Zinc and copper are the prosthetic groups of several metalloenzymes including superoxide dismutase (SOD) which is an important antioxidant enzyme in the cellular protection from reactive oxygen species. If concentrations of these trace elements decrease significantly, SOD cannot detoxify harmful oxygen species. In this study, adult male rats (wistar-albino) were exposed to formaldehyde at different periods (subacute and subchronic) and concentrations (0; 12.2; 24.4 mg.L-1). Body and testis weights were recorded and compared with control groups. The metals described above were determined in rat testicular tissue by atomic absorption spectrometry by using wet ashing. We conclude that subacute or subchronic exposure to formaldehyde have caused growth retardation and altered levels of trace elements, including copper, zinc and iron, in testicular tissue, and may induce further oxidative damage on testicular tissue leading to spermatozoal abnormalities.

OBJECTIVES: An understanding of the tissue and organ level of antioxidant enzymes that scavenge reactive oxygen species may provide an indication of their susceptibility to free radical-related cytotoxic damage. A direct association between testicular production of excessive reactive oxygen species and male infertility has been noted. We measured the activities of superoxide dismutase and glutathione peroxidase in the testes of thioacetamide-induced cirrhotic rats. METHODS: Antioxidant enzyme activities and trace element levels (copper, zinc, manganese, and selenium) in the testes of thioacetamide-induced cirrhotic and control rats were measured. The statistical difference between the experimental and control groups with regard to the activities of superoxide dismutase and glutathione peroxidase and levels of trace elements was analyzed with Student's t test. RESULTS: Our results showed a significant decrease in the activity of these enzymes in the testes of cirrhotic rats. The testicular levels of copper, zinc, and manganese, which are associated with these antioxidant enzymes, increased, whereas selenium decreased slightly in cirrhotic rats; that decrease was not statistically significant. CONCLUSIONS: Our studies showed a drastic decrease in the level of antioxidant enzymes in the testes of cirrhotic rats that could have deleterious effects on sperm function in these animals. Further studies are necessary to understand the exact pathways of trace element metabolism in the testes of cirrhotic rats.

Electron transfer from iron or copper ions to oxygen is an important example of cellular free radical initiation. Oxygen derived free radicals have been implicated as mediators of cellular injury in several model systems. To evaluate the importance of iron, copper and zinc levels on lipid peroxidation in peritonitis, we measured peritoneum malondialdehyde (MDA) as a marker of lipid peroxidation, zinc, copper, and iron levels during an animal model of intraperitoneal sepsis. Additionally the effects of the free radical scavenger alpha-tocopherol administration was studied. The peritoneum MDA, iron, copper and zinc levels were increased after induction of peritonitis with Escherichia Coli. The treatment with alpha-tocopherol was decreased the peritoneum MDA, iron and copper levels significantly, except the zinc level (p < 0.001, p < 0.001, p < 0.001, respectively). Additionally the alpha-tocopherol treatment for three days prior to injection of E.Coli more decreased MDA, copper and iron levels than that of the treatment with alpha-tocopherol at the time of injection of E. Coli (p < 0.001, p < 0.001, p<0.001, respectively). Our results indicated that copper, iron and zinc had important effects on peroxidation events in E. Coli induced peritonitis, and alpha-tocopherol treatment can improve the oxidant status.

It has been questioned whether carotenoids can act as antioxidants in biological membranes. Biological membranes can be modeled for studies of lipid peroxidation using unilamellar liposomes. Both carotenoid depletion and lipid peroxidation were increased with increasing oxygen tension in unilamellar liposomes. Carotenoids in such liposomes were found to be very sensitive to degradation by free radicals generated from iron and 2,2'-azobis(2-amidinopropane) dihydrochloride, but they were not protective against lipid peroxidation. Lycopene and beta-carotene were more sensitive to free radical attack than lutein, zeaxanthin, and beta-cryptoxanthin.