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L Trefil

Publications and source records attributed to L Trefil.

At least 19 recordsLinked to original sources
PubMed2006

Effect of white wine consumption on oxidative stress markers and homocysteine levels.

The aim of this study was to assess the influence of regular daily consumption of white wine on oxidative stress and cardiovascular risk markers. Forty-two healthy male volunteers consumed 375 ml of white wine daily. Each participant provided three venous blood samples (before wine consumption, following the wine consumption period and again a month later). Levels of superoxide dismutase, glutathione peroxidase, reduced glutathione, total antioxidant capacity, total cholesterol, HDL-cholesterol, apolipoprotein A I, apolipoprotein B, triglycerides, paraoxonase 1, C-reactive protein, homocysteine, thiobarbituric acid reactive substances (TBARS) and advanced oxidation protein products (AOPP) were measured. Immediately following the month of white wine consumption there was a significant increase in HDL-cholesterol (p<0.0001), paraoxonase 1 (p<0.001), glutathione peroxidase (p<0.001) and reduced glutathione (p<0.01) levels, a decrease in superoxide dismutase activities (p<0.0001), and a decrease in oxidation protein products (p<0.001) and TBARS (p<0.05) concentrations. However, there was also a clear increase in homocysteine (p<0.0001) after a month of white wine consumption. The results of our non-placebo controlled trial suggest that regular daily white wine consumption is associated not only with both antioxidative and antiatherogenic effects but also with a potentially proatherogenic increase of homocysteine concentrations.

Adult↗
PubMed2005

Folate co-administration improves the effectiveness of fenofibrate to decrease the lipoprotein oxidation and endothelial dysfunction surrogates.

Fibrate therapy results in elevation of plasma total homocysteine (tHcy), which is known to induce oxidative stress and endothelial dysfunction. We aimed to establish whether fibrate-induced elevation of tHcy has also similar consequences and whether they may be prevented by folate co-administration. Eighteen subjects with hypercholesterolemia were included in an open, prospective, cross-over study. We compared intra-individually the effect of fenofibrate on tHcy, oxidative stress and endothelial dysfunction surrogates, in monotherapy and when combined with 10 mg of folate. These effects were also compared with fluvastatin monotherapy. Fenofibrate in monotherapy significantly decreased LDL cholesterol, increased the tHcy by 39.5 %, while oxidized LDL (oxLDL), malondialdehyde (MDA), von Willebrand factors (vWf) and thrombomodulin (TMD) remained unchanged. When fibrate was co-administered with folate, the tHcy remained on the initial post-diet level, while both the total and oxLDL as well as MDA, vWf and TMD decreased. In contrast to fenofibrate monotherapy, fluvastatin (80 mg) had a similar effect as combined therapy with fenofibrate and folate, while tHcy remained uninfluenced. In conclusion, fenofibrate decreases the LDL cholesterol, but in contrast to fluvastatin, has no significant antioxidative and endothelium-protective potential, probably due to a concomitant increase of tHcy. These effects may be improved by co-administration of folate.

Adult↗
PubMed2005

The influence of folate and antioxidants on homocysteine levels and oxidative stress in patients with hyperlipidemia and hyperhomocysteinemia.

The aim of this study was to observe the effect of folate and antioxidants alone on homocysteine levels and oxidative stress markers, and to evaluate whether their co-administration promotes their effects. One hundred patients with hyperhomocysteinemia were randomized into four equal groups, which were then treated with folate, antioxidants or folate plus antioxidants for 2 months; group IV was a control group. Serum homocysteine, folate and oxidative stress markers were measured before the study, at the end of folate and/or antioxidants administration and 3 months later. Folate caused a significant decrease in homocysteine concentration. Antioxidants did not influence homocysteine concentration, but they improved the antioxidative defense (plasma antioxidant capacity and intraerythrocyte glutathione were increased) and partially prevented lipid peroxidation (malondialdehyde level was slightly decreased). Supplementation with folate had a similar effect on intracellular glutathione and plasma malondialdehyde. Simultaneous administration of folate and antioxidants did not show any additive effect with the exception of a slower decrease of folate concentration after its supplementation had been discontinued. Folate may be considered as an effective antioxidant in patients with hyperhomocysteinemia; this can be a result of decreased production of free radicals due to a reduced level of homocysteine. Its antioxidative effect cannot be promoted by co-administration of antioxidants.

Adult↗
PubMed2004

Markers of oxidative stress in diabetic mothers and their infants during delivery.

Oxidative stress is probably a pathophysiological process leading to disadvantageous outcomes in diabetic pregnancies. We aimed to map a complex of potential markers of oxidative stress in this condition. Diabetic mothers had significantly higher concentrations of thiobarbituric acid reactive substances in the plasma [TBARS] both before (p<0.0001) and after (p<0.001) delivery and also their newborns showed higher values of TBARS (p<0.0001) in comparison with the control group. Diabetic mothers also showed lower concentrations of reduced glutathione in erythrocytes [GSH] both before (p<0.05) and after (p<0.01) delivery and their infants also had lower levels of GSH (p<0.0001). We found a lower total antioxidative capacity of plasma [AOC] before delivery (p<0.05) in the diabetic group in comparison with the control group. Newborns of diabetic mothers had higher plasmatic concentrations of apolipoproteine B [apo B] (p<0.05), higher erythrocyte glutathione peroxidase [GPx] activity (p<0.05) and lower pH (p<0.001) in the umbilical cord blood, when compared with infants of control non-diabetic mothers. We conclude that pregestational and gestational diabetes mellitus represent increased oxidative stress for both mother and her infant. TBARS in plasma are a valuable marker of oxidative stress in this condition. Disruption of glutathione peroxidase/glutathione pattern can be involved in pathophysiology of enhanced oxidative stress in diabetic pregnancies.

Adult↗
PubMed2003

Can ischemia-reperfusion syndrome in transplanted kidneys procured from non-heart-beating donors be influenced by adding selenium into the reperfusion solution? An experimental study.

Ischemia-reperfusion syndrome significantly influences the function of a kidney transplanted from a non-heart-beating donor (NHBD). An animal model of NHBD was used to monitor the influence of the exogenous addition of selenium in the perfusion solution (HTK, Custodiol) on the generation of free oxygen radicals between 0 and 120 minutes after transplantation of the NHBD organ. During this interval, the malondialdehyde concentration, an indicator of free oxygen radicals in the venous blood of the transplanted kidney, significantly decreased. The augmentation of the anti-oxidant capacity of the preservation solution might represent a possible improvement in the function of kidneys transplanted from NHBDs.

Animals↗
PubMed2003

Can the ischemia-reperfusion syndrome in transplanted kidneys procured from non-heart-beating donors be influenced by adding selenium into the reperfusion solution? An experimental study.

The ischemic-reperfusion syndrome significantly influences the function of a kidney transplanted from a non-heart-beating donor (NHBD). The animal model of a NHBD was used to monitor the influence of exogenous addition of selenium into the reperfusion solution (HTK, Custodiol) with respect to the formation of free oxygen radicals at 0 to 120 minutes after the NHBD transplantation. This maneuvers produced a statistically significant decrease in malondialdehyde concentration, an indicator of free oxygen radicals in the venous blood of the transplanted kidney. The augmentation of the antioxidative capacity of the preservation solution might be a possible route to improve the function of kidneys transplanted from NHBDs.

Animals↗
PubMed2002

[Free radicals and antioxidants in cerebrospinal fluid in central nervous system diseases].

Free radicals and antioxidants may play a role in the etiology and pathogenesis of some central nervous diseases. The brain tissue is relatively insufficiently protected by antioxidants against the free radical induced damage. The brain situation may be reflected by the cerebrospinal fluid examination, which has not enough attention. It seems, that from this point of view subarachnoical hemorrhagy, meningitis, hydrocephalus, Alzheimer's, Parkinson's and Huntington's diseases, multiple sclerosis and probably schizophrenia should receive a special attention.

Antioxidants↗
PubMed2002

Hyperinsulinemia and oxidative stress.

The aim of the study was to compare the effect of short-term hyperglycemia and short-term hyperinsulinemia on parameters of oxidative stress in Wistar rats. Twenty male rats (aged 3 months, average weight 325 g) were tested by hyperinsulinemic clamp (100 IU/l) at two different glycemia levels (6 and 12 mmol/l). Further 20 rats were used as a control group infused with normal saline (instead of insulin) and 30 % glucose simultaneously. Measured parameters of oxidative stress were malondialdehyd (MDA), reduced glutathion (GSH) and total antioxidant capacity (AOC). AOC remained unchanged during hyperglycemia and hyperinsulinemia. Malondialdehyde (as a marker of lipid peroxidation) decreased significantly (p<0.05) during the euglycemic hyperinsulinemic clamp, and increased significantly during isolated hyperglycemia without hyperinsulinemia. Reduced glutathion decreased significantly (p<0.05) during hyperglycemia without hyperinsulinemia. These results suggest that the short-term exogenous hyperinsulinemia reduced the production of reactive oxygen species (ROS) during hyperglycemia in an animal model compared with the control group.

Analysis of Variance↗
PubMed2002

[Initial experience with transplantation of a kidney from a non-beating heart donor (NHBD)].

The authors present their initial experience with transplantations of the kidneys from a donor with a non-beating heart (NHBD). This programme was developed because of the permanently declining number of cadaverous kidney donors with a beating heart. Since January 2002 the authors collected a total of three kidneys from NHBD 3 kidneys of which were used for transplantation. The first two started to function immediately, the third one restored its function three weeks after transplantation. The viability and suitability of use of kidneys from NHBD is evaluated with regard to vascular resistance and flow of the perfusion fluid through the kidneys when using a perfusion pump and by means of totalglutathione-S-transferase (tGST) assessed at intervals in the perfusion fluid. The values of the above parameters are limiting between the 6th and 8th hour after the onset of instrumental perfusion of the collected kidneys when the perfusion values should be within the range of 30-50 ml/min/100 g and the vascular resistance should be < 0.7 mmHg and tGST < 100 U/l. For immunosuppression the authors use during the fist days after transplantation basiliximab, rapamycin and corticoids, later in case of satisfactory function of the graft they add cyclosporin A. The initial results of renal transplantation from NHBD are promising and the programme will be developed further.

Cadaver↗
PubMed2001

Submaximal exercise in healthy volunteers: the relationship between gastric mucosal and systemic energy status.

The effect of exercise on gastric mucosal energy status has not been fully elucidated. The aim of this study was to evaluate the impact of submaximal cycling on gastric mucosal energy balance and its relationship to changes in systemic energy status. Ten healthy volunteers (age 20-40 years) were investigated at rest (BL), during 30 min of submaximal exercise (E) on bicycle ergometry and during the 30 min after the completion of cycling. Gastric mucosal PCO(2) ( P(gm)CO(2)) was measured by air tonometry at 10-min intervals and the gastric mucosal-arterial PCO(2) difference ( PCO(2)gap) was calculated. Hemodynamics, arterial blood gases, lactate and pyruvate were also measured. PCO(2)gap significantly increased throughout exercise [BL: 0.2 kPa (median), -0.1-0.6 kPa (25th-75th percentiles); E(10 min): 1.0 kPa, 0.8-1.7 kPa; E(20 min): 1.35 kPa, 0.8-1.8 kPa; E(30 min): 1.5 kPa, 0.9-2.0 kPa]. The early changes in PCO(2)gap ( PCO(2)gap at E(10 min) minus PCO(2)gap at BL) correlated significantly and positively with corresponding changes in arterial lactate ( r(2)=0.58, P<0.05) and lactate-to-pyruvate ratio ( r(2)=0.72, P<0.05). On recovery, all metabolic parameters normalized within 30 min. We conclude that submaximal cycling in volunteers leads to the early derangement of gastric mucosal energy balance. The time course of PCO(2)gap parallels changes in systemic energy status.

Adult↗
PubMed2001

Effects of a vitamin E-modified dialysis membrane and vitamin C infusion on oxidative stress in hemodialysis patients.

Hemodialysis deteriorates oxidative stress. Vitamin E is an antioxidant whose regeneration is provided for by vitamin C. The authors tested the effects of a vitamin E-modified membrane (E), nonmodified cellulose membrane (O), and vitamin C infusion (500 mg, C) into the arterial blood line during dialysis on parameters of oxidative stress. In a short-term study, 24 patients were subjected to a single dialysis session with E, O, E with C, and O with C protocols. In a long-term study (12 weeks), 20 patients were randomized into groups with C and without C on each dialysis, and both groups had dialysis using O, E, and again O membrane for 4 weeks each. In the short-term study, thiobarbituric acid reacting substances (TBARS) in plasma rose after dialysis (p < 0.02) with O, and no changes were observed in the other 3 protocols. In the long-term study, predialysis TBARS declined when using E both in the groups with C (p < 0.02) and without C (p < 0.05). A switch over to O resulted in TBARS returning to baseline levels. The E membrane prevented an increase in lipid peroxidation during single dialysis, and long-term use of the E membrane also resulted in a decrease in the predialysis lipid peroxidation level. The antioxidant capacity of the E membrane was not enhanced by vitamin C infusion. High doses of vitamin C administered during dialysis using a nonmodified cellulose membrane prevented an increase in lipid peroxidation, most probably due to the enhanced rate of endogenous vitamin E regeneration.

Adult↗
PubMed2001

Effect of L-carnitine supplementation in hemodialysis patients.

BACKGROUND/AIM: L-Carnitine is important in beta-oxidation of fatty acids. A lack of carnitine in hemodialysis patients is caused by insufficient carnitine synthesis and especially by its loss during dialysis. The aim of our study was to test the influence of carnitine supplementation on plasma lipids, red blood cell count, and metabolism of free radicals. METHODS: Twelve regularly dialyzed patients (average age 55.5 years, average dialysis treatment period 22.5 months) were given 15 mg/kg L-carnitine intravenously three times weekly (after each hemodialysis session) for 6 months. Laboratory markers of oxidative stress, lipid metabolism, and red blood cell count were measured before the supplementation and then controlled during two 3-month intervals. Nine patients were retested 3 months after the supplementation had ended. RESULTS: All supplemented patients showed increased plasma free carnitine in comparison with the pretreatment values (113.3 +/- 11.2 vs. 62.3 +/- 16.7 micromol/l, p < 0.001). The proportion of decreased L-carnitine values after hemodialysis was reduced from 79 to 22%. Plasma total cholesterol (4.66 +/- 0.30 mmol/l after treatment vs. 5.65 +/- 1.53 mmol/l before treatment, p < 0.05) and LDL cholesterol (1.74 +/- 0.86 vs. 2.81 +/- 1.43 mmol/l, p < 0.05) decreased. The albumin concentration significantly increased from 34.8 +/- 7.3 to 46.0 +/-5.4 g/l (p < 0.05). Intraerythrocyte reduced glutathione increased from 1.65 +/- 0.25 to 2.23 +/- 0.16 mmol/l (p < 0.001), and the plasma antioxidant capacity increased from 1.65 +/- 0.09 to 2.06 +/- 0.17 mmol/l (p < 0.001). At the same time, plasma malondialdehyde decreased from 4.18 +/- 0.72 to 3.07 +/- 0.35 micromol/l (p < 0.001). The erythropoietin dose could be reduced from an average value of 5,500 to 3,500 U/week. No significant changes in the above-mentioned parameters were observed in a control group of dialyzed patients without L-carnitine supplementation. CONCLUSION: Regular carnitine supplementation of hemodialysis patients can improve their lipid metabolism, protein nutrition, red blood cell count, and antioxidant status.

Adult↗
PubMed2001

[Antioxidant effects of melatonin].

Increase in knowledge about reactive oxygen species action mechanisms and oxidative stress effects in living organisms led to intensive seeking for new, more effective substances, which prevent extreme development of oxidative stress or are able to decrease its negative influence, damaging cell structures and many cell functions. These substances are called antioxidants, scavengers, trappers or quenchers. In nineties, melatonin became the centre of the interest in the filed of investigation of antioxidative properties of different chemical substances. This is in living organisms ubiquitous substance with relatively simple chemical structure, good physical properties and wide physiological effects. The main role of endogenous melatonin comprises receptor-mediated biological rhythms synchronisation. Among other functions mentioned later belong anti-gonadotropic, immunotropic and non-receptor-mediated antioxidative effects. Melatonin is said to have also antineoplastic properties. Its anti-aging effect is discutable.

Analgesics↗
PubMed2001

Does exogenous melatonin influence the free radicals metabolism and pain sensation in rat?

Melatonin has been shown to play a role in antioxidative defence. We therefore studied its effect on oxidative damage to the rat cerebral cortex evoked by painful stimulation and immobilization-induced stress. Moreover, the effect of melatonin on chronic pain perception was examined. Rats were injected with either a high dose of melatonin (100 mg/kg i.p.) or a vehicle for five days and were subjected to painful stimulation or immobilization stress 30 min after the treatment. To determine the degree of oxidative stress, the levels of free radicals, thiobarbituric acid reactive substances (TBARS) as indicators of lipid peroxidation and glutathione peroxidase (GSHPx) were estimated in somatosensory cortex. Pain perception was measured by the tail-flick and plantar test. Melatonin reduced the level of TBARS previously increased by painful stimulation. Melatonin also exhibited a slight analgesic effect in those animals exposed to painful stimulation but its role in free radical scavenging did not contribute to this effect.

Animals↗
PubMed2000

[Antioxidative properties of ascorbic acid].

Vitamin C (ascorbic acid) is an important hydrophilic compound with antioxidative effect. In the introduction the authors describe possible consequences of loss of vitamin C synthetic ability in an evolutionary ancestor of Anthropoidea. Metabolism of this vitamin is described briefly along with possibilities of its supplementation and determination in biological fluids. Highest attention is paid to metabolic effects of vitamin C, respectively to changes which can be observed after its deprivation, or after the supplementation with this vitamin. Protective effect of vitamin C against lipoperoxidation, its role in modulation of immunity and tumorigenesis are described. Many effects of vitamin C can be explained by its antioxidative activity. The authors show that under concrete conditions, administration of vitamin C can be accompanied by a prooxidative effect. Since vitamin C works in cooperation with other antioxidants, its administration in diseases which are followed by oxidative stress is move effective when used in combined preparations.

Animals↗