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Biomedical subjects

B Dugué

Publications and source records attributed to B Dugué.

At least 19 recordsLinked to original sources
PubMed2006

Maximal accumulated oxygen deficit and blood responses of ammonia, lactate and pH after anaerobic test: a comparison between international and national elite karate athletes.

The purpose of this study was to compare maximal accumulated oxygen deficit (MAOD) and the time course of blood markers of the anaerobic metabolism in response to exhaustive supramaximal test in two elite (international vs. national) class karate athletes. Ten male international competitors from the French national team (Int, age 21.2 +/- 3.1 years, 71.9 +/- 11.4 kg) and eight national class (Nat, 23.7 +/- 2.4 years, 70.7 +/- 12.2 kg) athletes with a similar maximal oxygen uptake of 57.6 and 59.4 ml . kg (-1) . min (-1), respectively, were involved in this study. The MAOD was determined after an exhaustive supramaximal exercise (2 - 3 min at 140 % of their VO2max velocity) on a treadmill ergometer. Blood lactate, pH and plasma ammonia were determined at rest, immediately at the end of exercise and during the recovery period at 2, 4, 6, 8, 10 and 15 min. After the supramaximal exercise, a dramatic higher increase in the blood concentration of ammonia until its peak was observed in the Nat compared with the Int. Time course of [NH4+] and [La] reveals significant (p < 0.01) differences between the two groups. Peak values for [H+] (89.2 +/- 6.7 vs. 75.9 +/- 8.8 nmol . l (-1); p < 0.01), [NH4+] (180 +/- 67.9 vs. 118.7 +/- 22.7 micromol . l (-1); p < 0.05) and [La] (20.7 +/- 2.7 vs. 17.9 +/- 1.1 mmol.l (-1); p < 0.05) were higher in Nat compared with Int group, respectively. However, the MAOD was similar in both groups (67.8 +/- 8 ml . kg (-1) and 64.5 +/- 6.4 for Int and Nat groups, respectively). These data suggest that ammonia and lactate accumulation are sensitive to the level of performance in karate. Higher concentrations of these metabolites in blood after supramaximal exhaustive exercise may be related to either higher anaerobic contribution to energy supply in Nat or higher removal ability in the Int group.

Adult↗
PubMed2006

Lung function after acute and repeated exposures to extremely cold air (-110 degrees C) during whole-body cryotherapy.

Whole-body cryotherapy (WBC) is one mode of cold therapy, during which rheumatic patients are exposed to very cold air (-110 degrees C) in minimal clothing. It is also proposed to have a bronchodilatory effect. The aim was to examine the effects of WBC on lung function in healthy humans after acute and repeated exposures. Twenty-five healthy, non-smoking subjects participated in the study. They were exposed to WBC for 2 min three times per week for 12 weeks. The peak expiratory flow rate (PEF) and forced expiratory volume in 1 s (FEV1) were measured before and after (at 2 and 30 min) the first WBC, and then similarly at 4, 8 and 12 weeks. At all time points, after 30 min of the WBC the PEF values were slightly lower compared with values before the WBC, and the reductions reached statistical significance at 1 month (5.1 +/- 1.2%), and at 3 months (3.2 +/- 1.7%). After 30 min of the first WBC, the FEV1 was significantly reduced by 2.3 +/- 0.8%, but no other changes were observed during the study. In conclusion, the WBC induced minor bronchoconstriction in healthy humans instead of proposed bronchodilatation. The WBC seems not to be harmful for lung function, but should be used with caution in susceptible individuals.

Bronchoconstriction↗
PubMed2005

Acute and long-term effects of winter swimming and whole-body cryotherapy on plasma antioxidative capacity in healthy women.

The effects of severe cold stress on total peroxyl radical trapping antioxidant capacity of plasma (TRAP) were studied in two groups of healthy women: a whole-body cryotherapy group (WBC, n = 10) and a winter swimming group (WS, n = 10). The biovariability of TRAP values was also analysed. The WBC group was exposed to -110 degrees C for 2 min, whereas the exposure for the WS group lasted 20 s in ice-cold water. Sessions were organized three times per week for 12 weeks. Blood specimens were collected at 2, 4, 8 and 12 weeks at rest, 2 and 35 min after the cold exposures and at the corresponding times without cold exposure on a separate day. Conventional methods were used to determine TRAP values. The between-subject variation was 13.6% and the within-subject variation 6.4%. The index of individuality was 0.46, and the index of heterogeneity was 0.079. These results indicate a marked heterogeneity among subjects. During the first 4 weeks, the mean TRAP value significantly increased at 2 min after cold exposure in the WBC group, returning to baseline 35 min after the exposure. Similar changes were observed in the WS group. However, all changes due to cold were relatively mild (<5%). After 4 weeks no changes in TRAP values after the cold exposures were noticed and no long-term changes in basal TRAP values were observed. In the main, regular WBC and WS do not seem to be harmful as far as plasma antioxidative capacity is concerned.

Adult↗
PubMed2001

The driving license examination as a stress model: effects on blood picture, serum cortisol and the production of interleukins in man.

We have studied the following stress model: the tension caused by sitting for the theoretical part of the driving license examination. Volunteers were investigated twice, after their driving license examination and after a (stress-free) control session. The effects of the stress were investigated by studying the blood picture (differential counts), serum concentration of cortisol, and cytokine production in stimulated blood cells. Relationships between the subjective perception of stress and the physiological reaction were also investigated. This stress induced significant increase in the concentrations of cortisol and hemoglobin, and in the values of hematocrit and MCV, and in the lipopolysaccharide-induced release of IL-1beta and -6. The subjective feelings of irritability and wakefulness were also significantly higher after the exam. A significant relationship was found between the changes in the stimulated production of IL-1beta and irritability. The responsiveness to psychological stress might be influenced by the temporary mood of the subjects.

Adolescent↗
PubMed2001

Validation of a rating scale of perceived exertion in young children.

The aim of this study was to develop and validate a scale rating the perceived exertion of young children (RPE-C) who do not read. This scale presents seven pictures showing a man who becomes progressively fatigued. In order to evaluate this scale, we examined its reliability and sensitivity. Thirteen children (aged 5 to 6 years) completed two identical incremental maximal running trials during a period of one week. A group of 12 adolescents and a group of 12 adults also tested the RPE-C by performing one trial under the same experimental conditions as the child group. RPE-C was recorded at the end of each load level. Statistical analysis revealed significant effects for velocity (F = 23.98, p < 0.0001) with non-significant effects for the trials. Intraclass correlation coefficient (ICC) revealed an acceptable reliability of RPE-C at low and high exercise intensities but also showed a low reliability at intermediate load levels (0.17 < ICC < 0.77). A significant correlation between RPE-C and heart rate (r2 = 0.61, p < 0.0001) was observed in children. However, the r2 level was lower than that observed for the adolescent or adult groups. This finding demonstrates the sensitivity of RPE-C to discriminate the effects of age on perceived exertion. RPE-C seems to be a good tool which can be used in young children to monitor exercise performed at low and high intensities.

Age Factors↗
PubMed2001

Does endurance or sprint training influence the perception of the optimal pedalling rate during submaximal cycling exercise?

The purpose of this study was to investigate the effects of endurance and sprint training on the perception of the optimal pedalling rate during a submaximal cycling exercise. Six subjects specialized in endurance activities and 6 subjects trained in sprinting activities used the model of bicycling at various pedalling rates with the same power output (150W) on a cycle ergometer. Individual 2nd order polynomial relationships were determined between oxygen consumption (VO(2)) and velocity and between rate of perceived exertion (RPE) and velocity. Optimal velocity, with respect to minimum of VO(2) (OV(VO2)) and to minimum of RPE (OV(RPE)), were calculated for all subjects, respectively. The close similarity found between the VO(2)-velocity and the RPE-velocity curves confirmed that the overall RPE was mainly influenced by the central factor. As OV(RPE) and OV(VO2) were not significantly correlated and as OV(RPE) was significantly higher than OV(VO2), other factors than central may also have influenced the RPE. The significant higher OV(RPE) values (p<0.05) observed in the sprint vs. endurance groups suggested that different training background may have influenced the RPE. These differences could also be explained by a significantly higher OV(VO2) in sprint than in endurance groups, the subjects being sensitive to the pedalling rate for which the energy expenditure is minimal.

Adult↗
PubMed2000

Hydrogen peroxide attenuates store-operated calcium entry and enhances calcium extrusion in thyroid FRTL-5 cells.

Redox modulation participates in the regulation of intracellular free calcium concentration ([Ca(2+)](i)) in several cell types. In thyroid cells, including FRTL-5 cells, changes in [Ca(2+)](i) regulate several important functions, including the production of H(2)O(2) (hydrogen peroxide). As H(2)O(2) is of crucial importance for the production of thyroid hormones, we investigated the effects of H(2)O(2) on [Ca(2+)](i) in thyroid FRTL-5 cells. H(2)O(2) itself did not modulate basal [Ca(2+)](i). However, H(2)O(2) attenuated store-operated calcium entry evoked by thapsigargin, both in a sodium-containing buffer and in a sodium-free buffer. The effect of H(2)O(2) was abrogated by the reducing agent beta-mercaptoethanol. H(2)O(2) also attenuated the thapsigargin-evoked entry of barium and manganese. The effect of H(2)O(2) was, at least in part, mediated by activation of protein kinase C (PKC), as H(2)O(2) enhanced the binding of [(3)H]phorbol 12,13-dibutyrate. H(2)O(2) also stimulated the translocation of the isoenzyme PKCepsilon from the cytosolic fraction to the particulate fraction. Furthermore, H(2)O(2) did not attenuate store-operated calcium entry in cells treated with staurosporine or calphostin C, or in cells with down-regulated PKC. H(2)O(2) depolarized the membrane potential in bisoxonol-loaded cells and when patch-clamp in the whole-cell mode was used. The depolarization was attenuated in cells with down-regulated PKC. This depolarization, at least in part, explained the H(2)O(2)-evoked inhibition of calcium entry. In addition, H(2)O(2) enhanced the extrusion of calcium from cells stimulated with thapsigargin and this effect was abolished in cells with down-regulated PKC and after treatment of the cells with the reducing agent beta-mercaptoethanol. In conclusion H(2)O(2) attenuates an increase in [Ca(2+)](i). As H(2)O(2) is produced in thyroid cells in a calcium-dependent manner, our results suggest that H(2)O(2) may participate in the regulation of [Ca(2+)](i) in these cells via a negative-feedback mechanism involving activation of PKC.

Adenosine Triphosphate↗
PubMed2000

Extracellular ATP-mediated phospholipase A(2) activation in rat thyroid FRTL-5 cells: regulation by a G(i)/G(o) protein, Ca(2+), and mitogen-activated protein kinase.

We investigated the mechanism of phospholipase A(2) (PLA(2)) activation in response to the P2 receptor agonist ATP in rat thyroid FRTL-5 cells. The PLA(2) activity was determined by measuring the release of [(3)H]-arachidonic acid (AA) from prelabeled cells. ATP evoked a dose- and time-dependent AA release. This release was totally inhibited by pertussis toxin (PTX) treatment, indicating the involvement of a G(i)/G(o) protein. The AA release was also diminished by chelating extracellular Ca(2+) with EGTA or by inhibiting influx of Ca(2+) using Ni(2+). Although the activation of protein kinase C (PKC) by 12-phorbol 13-myristate acetate (PMA) alone did not induce any AA release, the ATP-evoked AA release was significantly reduced when PKC was inhibited by GF109203X or by a long incubation with PMA to downregulate PKC. Both the ATP-evoked AA release and the mitogen-activated protein kinase (MAP kinase) phosphorylation were decreased by the MAP kinase kinase (MEK) inhibitor PD98059. Furthermore, the ATP-evoked MAP kinase phosphorylation was also inhibited by GF109203X and by downregulation of PKC, suggesting a PKC-mediated activation of MAP kinase. Inhibiting Src-like kinases by PP1 attenuated both the MAP kinase phosphorylation and the AA release. These results suggest that these kinases are involved in the regulation of MAP kinase and PLA(2) activation. Elevation of intracellular cAMP by TSH or by dBucAMP did not induce a phosphorylation of MAP kinase. Furthermore, neither the ATP-evoked AA release nor the MAP kinase phosphorylation were attenuated by TSH or dBucAMP. Taken together, our results suggest that ATP regulates the activation of PLA(2) by a G(i)/G(o) protein-dependent mechanism. Moreover, Ca(2+), PKC, MAP kinase, and Src-like kinases are also involved in this regulatory process.

Adenosine Triphosphate↗
PubMed2000

Adaptation related to cytokines in man: effects of regular swimming in ice-cold water.

The cytokine response after thermal stress (sauna + swimming in ice-cold water) was investigated in subjectively healthy persons. Two groups were studied at the end of the winter season: habitual and inexperienced winter swimmers. Blood was collected at rest, after a sauna bath and after a short swim in ice-cold water. Conventional methods and ELISA kits were used to determined the blood picture, serum cortisol and dehydroepiandrosterone sulphate, plasma anti-diuretic hormone (ADH) levels, and the levels of several cytokines in plasma and in the supernatants of blood cell cultures which were stimulated with lipopolysaccharide (LPS). In regular winter swimmers, the concentrations of plasma interleukin 6 (IL-6), leukocytes, and monocytes at rest were significantly higher than in inexperienced subjects. In experienced female winter swimmers, the plasma concentration of the soluble receptor for IL-6 was significantly lower than in inexperienced female swimmers. In both groups, granulocytosis, haemoconcentration and significant increases in the concentrations of ADH, cortisol and IL-6 were observed after the stimuli. However, the changes in the cortisol concentration were dramatically larger in habitual winter swimmers. A significant correlation was found between the delta values of cortisol and the basal concentrations of IL-6. In cell cultures, the LPS-induced release of IL-1beta and IL-6 was higher at rest in the inexperienced winter swimmers. This release was dramatically suppressed after exposure to the stimuli in the inexperienced winter swimmers but tended to increase in the regular winter swimmers. These stresses appear to challenge both the neuro-endocrine and the immune systems and the results indicate that adaptive mechanisms occur in habitual winter swimmers.

Adaptation, Physiological↗
PubMed1999

Redox modulation of intracellular free calcium concentration in thyroid FRTL-5 cells: evidence for an enhanced extrusion of calcium.

Redox modulation is involved in the regulation of the intracellular free calcium concentration ([Ca2+]i) in several cell types. In thyroid cells, including thyroid FRTL-5 cells, changes in [Ca2+]i regulate important functions. In the present study we investigated the effects of the oxidizing compounds thimerosal and t-butyl hydroperoxide on [Ca2+]i in thyroid FRTL-5 cells. Thimerosal mobilized sequestered calcium, and evoked modest store-dependent calcium entry. Both compounds potently attenuated the increase in [Ca2+]i when store-operated calcium entry was evoked with thapsigargin. The entry of barium was not attenuated. Experiments performed with high extracellular pH, in sodium-free buffer and in the presence of vanadate suggested that thimerosal decreased [Ca2+]i by activating a calcium extrusion mechanism, probably a plasma membrane Ca2+-ATPase. All the observed effects were abrogated by the reducing agent beta-mercaptoethanol. The mechanism of action was apparently mediated via activation of protein kinase C, as thimerosal potently stimulated binding of [3H]phorbol 12, 13-dibutyrate, and was without effect on store-operated calcium entry in cells treated with staurosporine or in cells with down-regulated protein kinase C. Thimerosal did not depolarize the membrane potential, as evaluated using patch-clamp in the whole-cell mode. In immunoprecipitates obtained with an antibody against plasma membrane Ca2+-ATPase, we observed several phosphorylated bands in cells stimulated with thimerosal. In conclusion, we have shown that thimerosal attenuates an increase in [Ca2+]i, probably by activating a plasma membrane Ca2+-ATPase.

Animals↗
PubMed1999

Preanalytical factors (biological variation) and the measurement of serum soluble intercellular adhesion molecule-1 in humans: influence of the time of day, food intake, and physical and psychological stress.

BACKGROUND: Adhesion proteins such as soluble intercellular adhesion molecule-1 (sICAM-1) may be important markers for early atherosclerosis and some other diseases. To devise optimum specimen collection procedures, we investigated the effects on serum sICAM-1 of several preanalytical factors (factors that occur before a specimen is analyzed) such as the time of the day, food ingestion, and physical and psychological stress. METHODS: Three sets of experiments were conducted: (a) 30 subjects were investigated during the morning, after an overnight fast, and then after the usual breakfast and at 1200; (b) 20 subjects were studied before and after exposure to thermal stress (sauna + swimming in ice-cold water); and (c) 15 volunteers were investigated after their driving license examination and during a (stress-free) control session. Conventional methods and kits were used to determine the blood picture and serum sICAM-1. RESULTS: All of these preanalytical factors induced a significant increase ( approximately 10%) in the concentration of sICAM-1. CONCLUSION: It is advisable to consider timing, food intake, and stress when collecting specimens and analyzing data on the concentration of sICAM-1 in serum.

Adolescent↗
PubMed1998

Protein tyrosine phosphorylation and calcium signaling in thyroid FRTL-5 cells.

We examined the importance of tyrosine kinase(s) on the ATP-evoked Ca2+ entry and DNA synthesis of thyroid FRTL-5 cells. ATP rapidly and transiently tyrosine phosphorylated a 72-kDa protein(s). This phosphorylation was abolished by pertussis toxin and by the tyrosine kinase inhibitor genistein, and was dependent on Ca2+ entry. Pretreatment of the cells with genistein did not affect the release of sequestered Ca2+, but the capacitative Ca2+ or Ba2+ entry evoked by ATP or thapsigargin was attenuated. Pretreatment of the cells with orthovanadate enhanced the increase in intracellular free Ca2+ ([Ca2+]i), whereas the Ba2+ entry was not increased. Phorbol 12-myristate 13-acetate (PMA) phosphorylated the same protein(s) as did ATP. Genistein inhibited the ATP-evoked phosphorylation of MAP kinase and attenuated both the ATP- and the PMA-evoked DNA synthesis. However, genistein did not inhibit the ATP-evoked expression of c-fos. Furthermore, genistein enhanced the ATP-evoked release of arachidonic acid. Thus, ATP activates a tyrosine kinase via a Ca2+-dependent mechanism. A genistein-sensitive mechanism participates, in part, in the ATP-evoked activation of DNA synthesis. Genistein inhibits only modestly capacitative Ca2+ entry in FRTL-5 cells.

Adenosine Triphosphate↗
PubMed1998

A urinary radioisotope-binding assay to diagnose Gräsbeck-Imerslund disease.

BACKGROUND: Gräsbeck-Imerslund disease (congenital familial selective vitamin B12-malabsorption with proteinuria, MGA1, MIM No. 261100) is a rare disorder displaying autosomal recessive inheritance. This study was designed to investigate the usefulness of measuring the activity of the urinary receptor for the intrinsic factor-cobalamin complex as a tool to diagnose this disease. METHODS: The receptor activity was measured by a radioisotope-binding assay, using phenyl-Sepharose gel as the adsorbant solid phase of the receptor. RESULTS: In 10 Finnish patients, urinary receptor activity was on the average 640 times (15-1400 times) lower than that in 13 healthy control subjects: mean values of 0.1 nmol/mol (range, 0.01-0.32 nmol/mol) and 6.4 nmol/mol (range, 3.8-12.4 nmol/mol) creatinine, respectively. The mean value of urinary receptor activity in 11 first-degree, healthy relatives of the patients was 4.6 nmol/mol (range, 1.1-10.4 nmol/mol) creatinine, a difference from levels in control subjects that is not statistically significant. When the first-degree relatives were divided into heterozygotes (parents and siblings heterozygous for the haplotype of genetic markers associated with the disease gene) and wild-type homozygotes (siblings not displaying the disease haplotype), no difference was seen. CONCLUSION: Determination of receptor activity in the urine is a highly accurate method for diagnosis of Gräsbeck-Imerslund disease at an early stage, but it does not detect carriers of the disorder.

Absorption↗
PubMed1998

Short-term variability in the concentration of serum interleukin-6 and its soluble receptor in subjectively healthy persons.

The effects of the time of the day and breakfast on the outcome of interleukin-6 and its soluble receptor in serum were studied on 22 subjectively health volunteers. We collected blood specimens at 8.00 a.m. after an overnight fast, at 9.30 a.m. after usual breakfast, and at 11.30 a.m. A second group of volunteers (n = 20) was studied during the evening. We observed a significant decrease in the concentration of interleukin-6 after breakfast. This suggests that for assay of this analyte it is preferable to collect specimens after overnight fast. No changes were observed in the concentrations of interleukin-6 soluble receptor. Weak, but significant negative correlations were found between the age of the volunteers and the concentrations of interleukin-6 soluble receptor and between age and the ratio interleukin-6 soluble receptor/interleukin-6. The concentrations of interleukin-6 were positively and significantly correlated with age. The within-subject variability was 30% for interleukin-6, 13% for its receptor, and 33.1% for the ratio interleukin-6 soluble receptor/interleukin-6. The between-subject variability was 43.7% for interleukin-6, 22.2% for its receptor, and 60.2% for the ratio interleukin-6 soluble receptor/interleukin-6. The indices of individuality (ratio within-subject variability/between-subject variability) were calculated and found to be 0.69, 0.60, and 0.55 for interleukin-6, its soluble receptor, and the ratio interleukin-6 soluble receptor/interleukin-6, respectively. The implications of these indices with the use of health-related reference values is discussed.

Adolescent↗