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Biomedical subjects

J Racek

Publications and source records attributed to J Racek.

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↗
PubMed2006

Shape and size of dental arch--a five-year prospective study.

OBJECTIVES: The diagnostic procedure commences with the initial examination, during which a number of individual findings of the occlusion or malocclusion are clarified [1]. The objective is to describe the morphological and functional characteristics on each patient using specific guidelines, and then to provide a prognosis of the therapy. Upper and lower arch compression in first premolars and molars area was visible before treatment. METHODS: A special device (Czech technical university research prototype) was prepared for this purpose. The optical head contains a digital color camera. The front of the optical head consists of a removable prism which is put into the mouth. The findings can display live images from the camera, which can be archived on a PC. The device captured and geometrically calibrated images permitting comparison of several different dental casts. RESULTS: In the first part of this study 792 sets of study plaster casts were screened. Measurements of dental arch width between reference points of canines, first premolars and first molars were made: upper jaw: men: 3-3-35.1 mm (SE 0.13); 4-4-37.5 mm (SE 0.13); 6-6-48.1 mm (SE 0.19); women: 3-3-33.4 mm (SE 0.13); 4-4-35.6 mm (SE 0.15); 6-6-46.7 mm (SE 0.19). The second part concerns the group of 36 patients which is different from the 792 controls. There were studied changes between initial, post-treatment and post-retention alignment of upper and lower dental arch. CONCLUSIONS: Geometrically calibrated images help compare several different steps of the treatment and show a significant difference between patients before and after treatment.

Adolescent↗
PubMed2006

[Asymmetric dimethylarginine--a novel cardiovascular risk factor].

Understanding metabolism of nitric oxide (NO), signal molecule releasing from endothelial cells and influencing vascular tone, belongs to the most remarkable knowledge of last ten years. NO increases vascular tone, inhibits adhesion of monocytes and leukocytes to the vascular endothelium and reduces atherogenic process. Low NO level is one of pathogenic factors starting cardiovascular diseases. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of enzyme NO synthase, enzyme catalyzing NO production from arginine. This article gives a brief overview of contemporary state of the relation between ADMA and cardiovascular diseases. Increased ADMA levels are associated with reduced NO synthesis as assessed by impaired endothelium-dependent vasodilatation. In several prospective studies, ADMA evolved as a marker of cardiovascular risk. In the first chapters is described state of the art of biosynthesis, degradation and excretion of ADMA in connection with endothelial dysfunction, coronary artery disease, chronic heart failure, cardiovascular risk in haemodialysis patients, diabetes mellitus, hypertension, lipid metabolism disorders and intensive care unit treatment. Next chapters shortly summarize methods of ADMA detection and their applications. In conclusion clinical relevance of measurement of ADMA levels as a marker of endothelial dysfunction is discussed. Future research tasks of ADMA lead to prospective studies with different types of patients and also healthy population. Moreover ADMA is becoming a goal for pharmacotherapeutic intervention to improve endothelium-dependent vascular function in subjects with high ADMA levels.

Arginine↗
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↗
PubMed2004

Immunosuppresive agents have an influence on ischemia-reperfusion injury in kidneys procured from a non-heart-beating donor: experimental study.

Ischemic-reperfusion injury (IRI) has a considerable influence on the function of kidneys from non-heart-beating donors (NHBD) after transplantation. IRI is accompanied by a marked inflammatory reaction with the production of reactive oxygen species and of the proinflammatory cytokine tumor necrosis factor alpha. The effect on the development of ischemic-reperfusion injury of early treatment of the donor with mycophenolate mofetil and tacrolimus was monitored in an animal model of a NHBD. The study demonstrated that the combination of the two immunosuppressives reduced the production in the NHBD kidney of tumor necrosis factor alpha, an indicator of the degree of inflammatory reaction after reperfusion, to a considerable extent but not of malondialdehyde or reduced glutathione. Pre-treatment of marginal donors with these immunosuppressants may improve the immediate function of transplanted kidneys by reducing cytokine production.

Animals↗
PubMed2004

[The significance of free radicals and antioxidants due to the load induced by sport activity].

Sport performance is followed by a high production of free radicals. The main reasons are reperfusion after the previous imbalance between the increased need of the organism and the ability of blood supply by oxygen, increased production of ATP, decomposition of the cells particularly white blood cells, oxidation of the purin basis from DNA, stress, output of epinephrine release of free iron, increased temperature in the muscle and its inflammation, and the reception of free radicals from external environment. Peroxidation of lipids, proteins, DNA and other compounds follows the previous biochemical steps. Antioxidants are consumed by free radicals, antioxidative enzymes are released into blood plasma, intracellular calcium is increased, the production of nitric oxide rises, the levels of hydrogen peroxide and hypochlorous acid increase. These penetrate through the membranes and oxidatively damage the tissues. Training improves the ability of the organism to balance the increased load of free radicals. The damage can be lowered by the application of a mixture of antioxidants, the most important are vitamin C, A, E, glutathione, selenium, carnosine, eventually bioflavonoids and ginkgo biloba. The lack of antioxidants can significantly diminish the sport performance and therefore the supplementation with antioxidants is for top sportsmen but also for aged people advisable.

Antioxidants↗
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↗
PubMed2003

[Chromium as an essential element].

Chromium was known for many years to be an element causing allergic reactions and having neurotoxic and carcinogenic effects. These effects can be observed especially in the case of hexavalent chromium. Only a little more than four decades ago trivalent chromium has been known as an essential element with relation to glycide and lipid metabolism. And only during several last years this chromium function has been revealed on a molecular level. After absorption in the gastrointestinal tract, chromium is most likely transported to cells bound to the plasma protein transferrin. Insulin initiates chromium transport into the cells where it is bound to the oligopeptide apochromodulin. This oligopeptide combined with four chromium(III) atoms forms chromodulin, which is important for amplifying the insulin signalling effect. After binding to insulin-activated receptor, chromodulin increases tyrosine kinase activity by one order. This enzyme forms a part of intracellular portion of insulin receptor. Chromium supplementation in people with chromium deficiency can improve glucose tolerance and some lipid metabolism parameters. The supplementation is indicated in persons with impaired glucose tolerance both in preclinical and manifested stadium of type 2 diabetes mellitus where increased lost of chromium in urine was documented. In these patients, chromium deficiency can participate in insulin resistance and hyperlipidaemia. Chromium is usually applied in the form of organic compounds: yeast extract or chromium(III) picolinate. Cr(III) picolinate can be reduced to compounds of Cr(II) in the cells which can then produce free hydroxyl radical in the so called Fenton reaction.

Animals↗
PubMed2002

[Transitional elements and free radicals].

Iron and copper are essential trace elements, which in certain conditions, namely in the ionised form or in low-molecular complexes, can participate in single electron reactions and catalyse formation of free radicals, including the dangerous hydroxyl radical. Similar behavior have also some other transitive metals. Our overview is aimed on the role of transitive elements in the formation of free radicals and on the mechanisms that organisms have to prevent it. The highest attendance is given to the metabolism of iron and cooper. Consistent protection against free transitive metals (by binding with proteins, by oxidation or sequestration in a special compartment) enables organism to use their beneficial and required features without impairment of cell. Knowledge of these mechanisms provides the means to predict and effectively prevent the brake down of such defend systems in situations of the intravascular hemolysis, hemodialysis, administration of iron, impairments of the iron and copper metabolism, intoxication by oxidising substances etc.

Copper↗
PubMed2002

[Effect of a dialysis solution with icodextrin on ultrafiltration and selected metabolic parameters in patients treated with peritoneal dialysis].

BACKGROUND: To date, peritoneal dialysis has been performed almost exclusively using dialysis solutions containing glucose as the osmotic agent. Use of these solutions is fraught with problems regarding adequate fluid removal from the body and is also associated with undesirable metabolic effects; hence the search for alternative osmotic agents. A dialysis solution with the glucose polymer icodextrin generates ultrafiltration on the principle of colloidal osmosis. The aim of the study was to establish the effect of icodextrin-base dialysis solution on the magnitude of ultrafiltration and evaluate selected metabolic parameters of patients treated by ambulatory peritoneal dialysis. METHODS AND RESULTS: A total of 9 patients whose glucose-based solution was replaced by an icodextrin-based solution during the night-time exchange were evaluated. A control group of 9 patients used glucose-solution during all exchanges. Night-time bag ultrafiltration, blood pressure, and the serum levels of lipids, insulin, leptin, maltose, and amylase were determined before icodextrin administration (time 0), at one-month intervals (time 1, 2, 3), and one month after study completion (time 4). In icodextrin-treated patients, ultrafiltration rose from 246.5 +/- 60.5 ml (mean +/- SEM) at time 0 to 593.1 +/- 87.4 ml; p < 0.01, at time 1, to 547 +/- 67 ml; p < 0.05, at time 2, and to 586.7 +/- 58.8 ml; p < 0.01, at time 3, the icodextrin administration led to a rise in maltose from 0.02 +/- 0.01 g/l at time 0 to 0.1 +/- 0.1 g/l; p < 0.01, at time 1, to 1.0 +/- 0.09 g/l; p < 0.01, at time 2, and to 1.1 +/- 0.09 g/l; p < 0.01, at time 3, with a fall to zero values at time 4 (NS). Icodextrin administration was followed by a decrease in leptinemia from 34.6 +/- 17.2 ng/ml at time 0 to 21.7 +/- 8.9 ng/ml; p < 0.05, at time 1, to 21.4 +/- 9.5 ng/ml; p < 0.05, at time 2, and to 15.9 +/- 24.1 ng/ml; p < 0.05 at time 4. Insulin and lipid levels were not affected. There was no change in the above parameters in the control group. Icodextrin-treated patients reduced their antihypertensive medication, but not statistically significantly. CONCLUSION: Icodextrin administration significantly increase ultrafiltration thus providing for effective control of hydration status without the need for high-level glucose-based dialysis solutions. The use of a glucose polymer-based dialysis solution is associated with a significant yet reversible rise in serum maltose. The decrease in leptin may signal a reduction in body weight after replacing glucose in dialysis solutions with icodextrin, or enhanced rates of leptin elimination as a result of ultrafiltration-induced convective transport.

Adult↗
PubMed2002

Unexpected inverse relationship between insulin resistance and serum homocysteine in healthy subjects.

Mild hyperhomocysteinemia has been established as a new independent risk factor for atherosclerosis and thrombosis. The metabolic syndrome of insulin resistance is associated with a high risk of coronary heart disease. Our objective was to determine if any relationship exists between the metabolic syndrome of insulin resistance in non-diabetic subjects and total serum homocysteine levels. Sixty-six healthy volunteers (33 males and 33 females) were selected from the population of Pilsen. Insulin resistance was measured by the Insulin Suppression Test using Octreotide. Steady-state plasma glucose concentrations at the end of the test period provided a quantitative measure of insulin resistance. Serum homocysteine level was estimated by high-pressure liquid chromatography. Serum folate and vitamin B12 were estimated using commercial kits on an Abbott IMx analyzer. All other laboratory tests were performed by standard methods in a routine biochemical laboratory. Subjects with the highest tertile of steady-state plasma glucose showed a significantly higher body mass index, blood pressure, fasting plasma triglyceride levels, plasminogen activator inhibitor-1 and lower HDL-cholesterol, i.e. an insulin resistance pattern. These subjects had significantly lower serum homocysteine levels compared with non-insulin resistant subjects. The negative association of insulin resistance and serum homocysteine was unexpected. The contribution of plasma folate levels to serum homocysteine levels and serum creatinine was significantly negative and positive, respectively.

Age Factors↗