Biomedical subjects

A Mazur

Publications and source records attributed to A Mazur.

At least 19 recordsLinked to original sources

PubMed2006

Junctional rhythm quantity and duration during slow pathway radiofrequency ablation in patients with atrioventricular nodal re-entry supraventricular tachycardia.

AIM: The occurrence of accelerated junctional rhythm during radiofrequency energy delivery at the region of the slow pathway is a well-recognized marker of successful treatment of atrioventricular nodal re-entry tachycardia (AVNRT). Our aim was to evaluate if the quantity and duration of accelerated junctional rhythm during radiofrequency ablation of the slow pathway is correlated with residual slow pathway conduction. METHODS AND RESULTS: Forty consecutive patients with AVNRT undergoing radiofrequency ablation of slow pathway who developed accelerated junctional rhythm during ablation were included. We compared accelerated junctional rhythm quantity and duration between two groups: group A, without echo beats and group B, with echo beats on post-ablation electrophysiology study. The total amount of accelerated junctional rhythm was significantly greater in group A than in group B [75.0 (63.5-165.0) vs. 36.0 (24.0-65.0), P=0.006], as well as total duration of accelerated junctional rhythm [47.0(33.5-81.0) s vs. 23.0 (16.0-42.0) s, P=0.006]. The cycle length of accelerated junctional rhythm did not differ between the two groups [510.0 (445.0-545.0) ms vs. 500.0 (450.0-585.0) ms, P=0.5). CONCLUSIONS: The amount and duration of accelerated junctional rhythm is correlated with the total abolishment abolition of slow pathway conduction. A higher amount and duration of accelerated junctional rhythm during radiofrequency applications may be an additional marker of successful ablation.

Adult↗

PubMed2006

Effects of exercise and training in hypoxia on antioxidant/pro-oxidant balance.

OBJECTIVE: The aim was to investigate the effects of acute exercise under hypoxic condition and the repetition of such exercise in a 'living low-training high' training on the antioxidant/prooxidant balance. DESIGN: Randomized, repeated measures design. SETTING: Faculté de Médecine, Clermont-Ferrand, France. SUBJECTS: Fourteen runners were randomly divided into two groups. A 6-week endurance training protocol integrated two running sessions per week at the second ventilatory threshold into the usual training. INTERVENTION: A 6-week endurance training protocol integrated two running sessions per week at the second ventilatory threshold into the usual training. The first hypoxic group (HG, n=8) carried out these sessions under hypoxia (3000 m simulated altitude) and the second normoxic group (NG, n=6) in normoxia. In control period, the runners were submitted to two incremental cycling tests performed in normoxia and under hypoxia (simulated altitude of 3000 m). Plasma levels of advanced oxidation protein products (AOPP), malondialdehydes (MDA) and lipid oxidizability, ferric-reducing antioxidant power (FRAP), lipid-soluble antioxidants (alpha-tocopherol and beta-carotene) normalized for triacyglycerols and cholesterol were measured before and after the two incremental tests and at rest before and after training. RESULTS: No significant changes of MDA and AOPP level were observed after normoxic exercise, whereas hypoxic exercise induced a 56% rise of MDA and a 44% rise of AOPP. Plasma level of MDA and arterial oxygen hemoglobin desaturations after the acute both exercises were highly correlated (r=0.73). alpha-Tocopherol normalized for cholesterol and triacyglycerols increased only after hypoxic exercise (10-12%, P<0.01). After training, FRAP resting values (-21%, P<0.05) and alpha-tocopherol/triacyglycerols ratio (-24%, P<0.05) were diminished for HG, whereas NG values remained unchanged. CONCLUSIONS: Intense exercise and hypoxia exposure may have a cumulative effect on oxidative stress. As a consequence, the repetition of such exercise characterizing the 'living low-training high' model has weakened the antioxidant capacities of the athletes. SPONSORSHIP: International Olympic Committee and the Direction Régionale de la Jeunesse et des Sports de la Région Auvergne.

Adult↗

PubMed2006

Effect of daily versus twice weekly long-term iron supplementation on iron absorption and status in iron-deficient women: a stable isotope study.

OBJECTIVES: This work aims at studying the effect of daily versus twice weekly long-term Fe supplementation on Fe absorption and status in Fe-deficient women. DESIGN AND METHODS: The study design is a randomized controlled open study carried out in the Internal Medicine Department, CHU de Clermont-Ferrand, France. Twenty-four young women participated in this study and were randomized into two groups: Group 1 received 50 mg Fe daily, and group 2 received 50 mg Fe twice weekly for 3 months. On day 10 (D10) and on day 90 (D90) of Fe supplementation, blood samples were obtained, and women received orally about 5 mg of 57Fe, and blood was sampled at different times over 24 h. The 57Fe absorption was evaluated by calculating the areas under the curves (AUC). Fe and oxidative stress status were also assessed. RESULTS: 57Fe absorption was similar in both groups on D10 but was greatly decreased in Group 1 and remained high in Group 2 on D90. Fe status was more improved in Group 1 than in Group 2. Oxidative stress status remained statistically unchanged. CONCLUSIONS: Our study shows that daily Fe supplementation is able to correct an Fe deficiency much more than twice weekly Fe supplementation in young women.

Absorption↗

PubMed2006

Magnesium and neoplasia: from carcinogenesis to tumor growth and progression or treatment.

Magnesium is involved in a wide range of biochemical reactions that are crucial to cell proliferation, differentiation, angiogenesis, and apoptosis. Changes in magnesium availability have been shown to influence biological responses of immuno-inflammatory cells. Equally plausible seems to be an involvement of magnesium in the multistep and interconnected processes that lead to tumor formation and development; however, the "how" and "when" of such an involvement remain to be defined. Here, we reviewed in vitro and in vivo data that indicated a role for magnesium in many biological and clinical aspects of cancer (from neoplastic transformation to tumor growth and progression or pharmacologic treatment). In adopting this approach we went through a full circle from molecular aspects to observational or epidemiological studies that could reconcile in a unifying picture the otherwise fragmentary or puzzling data currently available on the role of magnesium in cancer.

Animals↗

PubMed2006

Childhood obesity: a pandemic of the twenty-first century.

BACKGROUND: The researchers and clinicians need to gain a better understanding of the social and environmental contexts by which childhood obesity is becoming a growing problem of twenty-first century and develop more efficacious methods of prevention and treatment. METHODS: Summary of the actions and achievements of the European Childhood Obesity Group (ECOG) since its foundation in 1991 until the 16th anniversary. Review of the sessions of the 16th ECOG workshop devoted to epidemiology, prevention, risk factors, comorbidities and treatment of childhood and adolescent obesity. RESULTS: Meta-analysis of epidemiological data on childhood obesity in Europe underscores an urgent need of preventive actions in which general practitioners may play an important role. Media should get actively involved in promotion of healthy lifestyle. Metabolic syndrome, non-alcoholic steatohepatitis, diabetes type 2 and sleep apnoea syndrome are becoming more common in obese adolescents. In morbid obesity with severe comorbidities, more aggressive ways of treatment may be considered. CONCLUSIONS: European Childhood Obesity Group members should get actively involved into targeted prevention and intervention project to promote healthy lifestyle and successful weight control.

Adolescent↗

PubMed2006

Are neutrons involved in the pathogenesis of life-threatening cardiac arrhythmias?

Geomagnetic fields protect the earth from the adverse effects of cosmic rays, whose activity can be indirectly measured by monitoring the level of neutrons in the environment. The number and days of discharges from automatic implantable cardioverter defibrillators (ICD) in patients with cardiac arrhythmias are inversely correlated with the daily level of geomagnetic activity (GMA). The aim of the present was to determine whether neutron levels on days of AICD discharges are higher than average. Days on which discharges occurred were recorded in 31 patients bearing ICDs for managing ischemic cardiomyopathy. Daily neutron levels obtained from the monitoring data of the Russian Academy of Sciences in Moscow were analyzed using Student's t test. The mean (+/-SD) daily neutron level for the 1096-day period was 8299.29 +/- 294.236 imp/min (median 8252), and for days of ACID discharge, 8423.93 +/- 274.187 imp/min (median 8443) (p = 0.0002). The mean neutron activity on days of AICD discharges in response to ventricular disturbances was significantly higher than the mean level over the 1096-day study period. Whether this relation is a direct result of low GMA or due to an independent role of neutrons in the pathogenesis and timing of cardiac arrhythmias is unknown.

Arrhythmias, Cardiac↗

PubMed2006

Plasma proteome analysis: 2D gels and chips.

The knowledge of concentration, modification and interaction of proteins is fundamental in determining the phenotype of living organisms. Plasma, the primary clinical specimen, contains numerous and diverse proteins. The functions of these proteins are as manifold as the diversity of the protein themselves. Many of them have been largely used for many years as biomarkers of diseases and indicators of the physiological functions. The study of plasma proteome promises to be a significant advance in various areas of biological and clinical research. Two-dimensional polyacrylamide gel electrophoresis is considered as a primary tool in separating thousand of plasma proteins. This approach enables comparing normal and diseased samples revealing differently expressed proteins. Other proteomic techniques suitable for plasma analysis such as protein microarrays are now either established or are still being improved. This article briefly reviews the application of two-dimensional electrophoresis and the current status of technical aspects for plasma proteome.

Blood Proteins↗

PubMed2005

Erythrocyte magnesium fluxes in mice with nutritionally and genetically low magnesium status.

Low intracellular magnesium (Mg) contents may be observed in case of severe Mg insufficient intake or because of genetic regulation. This work was conducted to investigate the influence of intracellular Mg content on erythrocyte Mg(2+) influx and efflux in mice with low nutritionally and genetically (MGL and MGH mice) Mg status. C57BL6 mice were fed for 2 wks a diet containing 1000 mg Mg/kg diet Mg (control group), 100 mg Mg/kg diet (Mg-marginal group) or 30 mg Mg/kg diet (Mg deficient group), while mice with low (MGL) and high (MGH) Mg levels were fed a control diet for 2 wks. The quantification of erythrocyte Mg(2+) influx and efflux was performed using a stable isotope of Mg. Our results showed that erythrocyte Mg(2+) influx and efflux were respectively increased and decreased in nutritional Mg deficiency; while in genetically determined Mg status Mg(2+) fluxes were lower in MGL mice compared to MGH mice. Moreover Mg(2+) efflux was significantly correlated to Mg level in erythrocytes in all the mice studied (p < 0.001). In conclusion, erythrocyte Mg(2+) influx and efflux are modulated by low Mg status, namely decreased Mg(2+) efflux compensate for nutritional Mg deficiency, while the genetic regulation of erythrocyte Mg(2+) content depends on modification of Mg(2+) influx.

Animals↗

PubMed2005

Impact of micronutrient dietary intake and status on intestinal zinc absorption in late middle-aged men: the ZENITH study.

BACKGROUND: Adjustments in intestinal absorption and losses of zinc (Zn) are thought to maintain Zn homeostasis when dietary intake levels are altered. Zn status may also influence efficiency of intestinal Zn absorption. OBJECTIVES: To determine the impact of dietary intake and status of some micronutrients on Zn absorption in late middle-aged men. DESIGN AND PARTICIPANTS: Dietary intake and status of Zn, Cu, Fe, vitamin A, C and fibre, and absorption of Zn were measured in 48 men, aged 58-68 y, confined to a metabolic unit and consuming a typical French diet. Dietary intake was estimated using 4-day food-intake records (including the weekend) and the GENI program. To assess Zn status, serum, erythrocyte, urine Zn levels and serum alkaline phosphatase activity were determined. Zn absorption was determined using the isotope double-labelling method. Zn stable isotopic ratios were measured in plasma samples collected before and 48 h after isotope administration using ICP/MS. RESULTS: Zn intake within the group of men varied from 5.7 to 20.5 mg/day and averaged 12.9 mg/day. Serum Zn level varied from 10 to 18 micromol/l and averaged 12.9 micromol/l. Zn absorption varied from 12 to 46% and averaged 29.7%. Zn absorption was not significantly (P > 0.05) correlated with Zn intake or with any of the Zn status parameters. Zn absorption was only slightly negatively correlated with serum and erythrocyte Zn levels and with serum Fe and ferritin levels in this study. CONCLUSION: Zn dietary intake and Zn absorption were satisfactory and led to an adequate Zn status in this population.

Aged↗

PubMed2005

Erythrocyte magnesium influx and efflux in solid tumor bearing mice.

Mg metabolism is modified in tumors and tumor-bearing organisms. In particular cancer patients often display elevated erythrocyte Mg levels. For a better understanding of the increased erythrocyte Mg content, we attempted to determine Mg fluxes in erythrocytes from tumor-bearing mice by Mg stable isotopes, using a method developed in our laboratory. To characterize the animal Mg status, blood and tissue Mg levels and hematological parameters were assayed. Results showed that in tumor-bearing mice total erythrocyte Mg was about 46% higher than in controls, whereas plasma and tissues Mg levels were not modified; red blood cells and hemoglobin as well as hematocrits were significantly decreased, while mean corpuscular volume and mean corpuscular hemoglobin were slightly but significantly increased in tumor-bearing mice compared to controls (by 3% and 4%, respectively), a picture corresponding to a normochromic, slightly macrocytic anemia. Erythrocyte Mg efflux was about 20% higher (404 + 59 versus 330 + 45 micromol/L, respectively, p < 0.05) in tumor-bearing mice compared to controls, whereas influx was not significantly modified (130 + 11 versus 122 + 19 micromol/L, respectively). Our data therefore exclude that the increased Mg content observed in erythrocytes of tumor-bearing mice is due to decrease of Mg efflux, or to an increase of Mg influx. On the other hand, the increased Mg content observed in erythrocytes of tumor-bearing mice could simply result from an increase of young Mg-enriched erythrocytes produced by the enhanced erythropoiesis which follows tumor-induced anemia.

Animals↗

PubMed2005

Study of magnesium bioavailability from ten organic and inorganic Mg salts in Mg-depleted rats using a stable isotope approach.

Literature data on the bioavailability of various Mg forms provide scarce information on the best Mg salt to be used in animal and human supplementation. This study aimed to investigate the bioavailability of different forms of Mg in rats using Mg stable isotopes. Eighty male Wistar rats aged 6 weeks were fed a semi-purified Mg-depleted diet for three weeks. The rats were then randomised into ten groups and received, for two more weeks, the same diet repleted with Mg (550 mg Mg/kg) as: oxide, chloride, sulphate, carbonate, acetate, pidolate, citrate, gluconate, lactate or aspartate. After 10 days of Mg-repleted diet, the rats received orally 1.8 mg of an enriched 26Mg. Faeces and urine were then collected for 4 consecutive days. Isotope ratios in faeces and urine were determined. The Mg absorption values obtained varied from 50% to 67%. Organic Mg salts were slightly more available than inorganic Mg salts. Mg gluconate exhibited the highest Mg bioavailability of the ten Mg salts studied. Urinary 26Mg excretion varied from 0.20 mg to 0.33 mg, and feeding with the organic pidolate, citrate, gluconate and aspartate salts resulted in higher urinary 26Mg excretion than with inorganic salts. Ultimately, 26Mg retention was higher in the rats receiving the organic salts such as gluconate, lactate and aspartate than in those receiving the inorganic salts. Taken together, these results indicate that 26Mg is sufficiently bioavailable from the ten different Mg salts studied in the present experiment, although Mg gluconate exhibited the highest bioavailability under these experimental conditions.

Animals↗

PubMed2004

Stimulatory effect of inulin on intestinal absorption of calcium and magnesium in rats is modulated by dietary calcium intakes short- and long-term balance studies.

Previous studies have shown that short-term intake of fermentable oligosaccharides (OS), including inulin, can increase mineral intestinal absorption in humans and animals. While the stimulatory effect of these substances on intestinal magnesium (Mg) absorption is generally high and consistent, their effect on calcium (Ca) seems to depend on experimental conditions, particularly the duration of fermentable OS intake. The aim of this study was to determine how the short- and long-term dietary Ca intake may modulate the effect of inulin on Ca absorption. Sixty male Wistar rats, weighing 275 g, were randomized into two groups to receive or not 10% of inulin in their diet. Each group was divided into three sub-groups to receive one of the following dietary Ca levels 0.25%, 0.50% and 0.75% in their food. The animals were fed fresh food and water ad libitum for 40 days. Apparent intestinal absorptions of Ca and Mg were determined at D13 and D36 of the experiment. As expected, inulin feeding increased Ca and Mg absorption in both periods at all dietary Ca levels. However, the effect of inulin on intestinal Ca absorption was dependent on dietary Ca levels and on experiment duration. In the short-term period, the inulin effect was prominent in the groups receiving high or low Ca levels, but in long-term period inulin improved intestinal Ca absorption much more in the group receiving the low Ca level. In addition, efficiency of intestinal absorption of Ca and Mg (%) was negatively affected by Ca intake levels. These results show that the beneficial effect of inulin on intestinal Ca absorption may be more marked in cases where the Ca intake is low or where the organism's Ca requirement is high. Further studies are required to confirm these results in humans.

Animals↗

PubMed2004

Magnesium metabolism in mice selected for high and low erythrocyte magnesium levels.

A genetic control of blood magnesium (Mg) levels has been suggested. To investigate the mechanisms and the biologic significance of this genetic regulation, a mouse model, ie, mice selected for low magnesium level (MGL) and high magnesium level (MGH), was developed. The purpose of this study was to explore the Mg status and Mg metabolism in female MGL and MGH mice. We observed that MGL mice had reduced total and ionized plasma Mg, lower erythrocyte Mg, lower tibia, and kidney Mg levels. In contrast, total urinary Mg and (25)Mg levels were significantly higher in MGL mice. MGL mice had smaller total Mg exchangeable pool masses compared with MGH, and fractional transport rates of Mg (exchange constant) were different. In vitro (25)Mg enrichments in erythrocytes from MGL mice were significantly lower. Moreover, Mg efflux from erythrocytes was significantly higher in MGL. In conclusion, this work demonstrates that MGL mice present lower body stores of Mg than MGH mice and lower body Mg retention. This is confirmed at a cellular level by a lower enrichment of (25)Mg in erythrocytes. The lower retention of Mg by MGL erythrocyte in comparison to MGH appears to be partly due to a higher Mg efflux in MGL erythrocyte. It can be hypothesized that a genetic factor that modulates Na(+)/Mg(2+) exchanger activity may be important in the regulation of Mg metabolism. Further investigations on the mechanisms responsible for differences in Mg retention between MGL and MGH mice could contribute to a better understanding of the genetic regulation of cellular Mg.

Animals↗

PubMed2004

Olive oil and its main phenolic micronutrient (oleuropein) prevent inflammation-induced bone loss in the ovariectomised rat.

The present study was designed to evaluate the effect of olive oil and its main polyphenol (oleuropein) in ovariectomised rats with or without inflammation. Rats (6 months old) were ovariectomised or sham-operated as control. Ovariectomised rats were separated into three groups receiving different diets for 3 months: a control diet with 25 g peanut oil and 25 g rapeseed oil/kg (OVX), the control diet with 50 g olive oil/kg or the control diet with 0.15 g oleuropein/kg. The sham-operated group was given the same control diet as OVX. Inflammation was induced 3 weeks before the end of the experiment by subcutaneous injections of talc (magnesium silicate) in one-half of each group. The success of ovariectomy was verified at necropsy by the atrophy of uterine horns. Inflammation, oleuropein or olive oil intakes did not have any uterotrophic activity, as they had had no effect on uterus weight. The plasma concentration of alpha-1-acid glycoprotein (an indicator of inflammation) was increased in OVX rats with inflammation. With regard to bone variables, osteopenia in OVX was exacerbated by inflammation, as shown by a decrease in metaphyseal and total femoral mineral density. Both oleuropein and olive oil prevented this bone loss in OVX rats with inflammation. At necropsy, oleuropein and olive oil consumption had had no effect on plasma osteocalcin concentrations (marker of bone formation) or on urinary deoxypyridinoline excretion (marker of bone resorption). In conclusion, oleuropein and olive-oil feeding can prevent inflammation-induced osteopenia in OVX rats.

Animals↗

PubMed2004

Changes in gene expression in the lungs of Mg-deficient mice are related to an inflammatory process.

It has been well documented that experimental hypomagnesemia in rodents evokes, as an early consequence, an inflammatory response. This also leads to the activation of cells producing reactive species of oxygen and, as a result, to the oxidative damage of tissues. Several studies have shown that lungs might be a specific target of Mg deficiency. Here, we report that 3 weeks of Mg deficiency in mice resulted in inflammatory processes in the lungs, including interstitial and perivascular pneumonia, manifested by the infiltration of leukocytes, plasmocytes and histiocytes, as well as the phenomenon of disseminated intravascular coagulation (DIC). These phenomena were accompanied by changes in gene expression assessed by cDNA array. In this study we identified 26 genes significantly changed by Mg deficiency, mostly involved in the anti-oxidative response, regulation of cell cycle and growth, apoptosis as well as cell-cell and cell-matrix interactions. We conclude that these changes are related to the phenomena of inflammatory and oxidative processes and consecutive remodeling occurring in the tissues as a result of Mg deficiency. This may have implications for at least several lung pathologies, including allergies, asthma, SIDS (Sudden Infant Death Syndrome) or facilitate formation of lung metastases.

Animals↗

PubMed2003

Increase in complement component C3 is an early response to experimental magnesium deficiency in rats.

The importance of the inflammatory process in the pathology of experimental Mg-deficiency has been reconsidered but the sequence of events leading to inflammatory response remains unclear. In this study, the effect of Mg-deficiency on complement system by measuring total C3 concentration, mRNA abundance for rat pre-pro complement C3 in liver by RT-PCR, complement haemolytic activity and C3 activation by Western Blot was studied. Weaning male Wistar rats were fed either Mg-deficient or control experimental diets for 2 or 8 days. At 8 days, a characteristic inflammatory response of Mg-deficiency including hyperaemia, leukocytosis and enlarged spleen was accompanied by an increase in the total C3 quantity in plasma. Moreover, at 8 days, RT-PCR analysis indicated higher level of mRNA rat pre-pro complement C3 in liver from Mg-deficient rats compared to control rats. Even if the inflammatory syndrome was not observed in rats after 2 days, total plasma C3 was shown to be significantly increased as compared to total plasma C3 level in control rats. Because of the high variability of complement haemolytic activity values in Wistar rats, weaning male Sprague-Dawley rats were used in a second experiment. At 8 days, the inflammatory response of Sprague-Dawley rats was accompanied by an increase in total C3 quantity and by a higher haemolytic activity. The Western Blot technique failed to display distinct bands resulting from C3 cleavage in plasma from Mg-deficient rats. Since, the complement C3 is a positive acute phase reactant, the elevation of C3 indicates that the modification of inflammatory response is an early event of Mg-deficiency. However, complement activation does not appear to be involved in the acute phase of the deficiency.

Animals↗

PubMed2002

Divergence in plasmatic and urinary isoprostane levels in type 2 diabetes.

BACKGROUND: Oxidative stress is currently suggested as a mechanism underlying diabetes. The present study was designed to evaluate isoprostane levels in plasma and in urine in type 2 diabetic patients, and to compare them to other currently used biomarkers of oxidative stress. METHODS: The work was performed in a control group (n = 10) and in a type 2 diabetic group (n = 10). Besides the traditional biochemical parameters, we evaluated the plasma and urine levels of isoprostanes and malondialdehyde (MDA) as markers of oxidative stress. RESULTS: We found increased plasma and urine MDA in the diabetic patients and almost significantly decreased plasma vitamin E. Urinary isoprostane levels in diabetic patients were increased but they presented a strong tendency to a decrease in plasma isoprostanes. It is therefore suggested that, in the studied diabetic patients, although the production of isoprostanes in the body was increased (as other plasma oxidative stress biomarkers were altered) it did not lead to an increase in plasma isoprostane levels. It could be hypothesised that this results from an increased elimination of this metabolite and therefore an increased excretion in urine. CONCLUSION: Our results showed that the measurement of same oxidative stress biomarker, isoprostane, in two different biologic fluids, plasma and urine, led to divergent results and emphasised the importance to measure a biomarker both in the circulation fluid (plasma) and in the elimination fluid (urine), to have a general idea of what is occurring in the organism.

Aged↗

PubMed2002

Causes of sexual decline in aging married men: Germany and America.

Married men in Germany (n=48) and America (n=50) between 50 and 80 years old, none in poor health, provided comparable information on sexual behavior and attitudes, and gave saliva samples from which testosterone was assayed. Sexuality declines with age, as expected. Neither testosterone nor psychological depression explain levels of sexuality. In both nations, wife's desire for intercourse, subject's ability to maintain an erection, and subject's imagination about other women, explain certain aspects of sexuality. Subject's health and marital satisfaction are related to sexuality among Americans but not among Germans. Behavioral models for the two nations are compared.

Coitus↗