PubMed Health⌕ Search

Biomedical subjects

M Rieu

Publications and source records attributed to M Rieu.

At least 19 recordsLinked to original sources
PubMed1992

Effect of moderate exercise on rat T-cells.

The aim of this study was a detailed examination of the effects of moderate exercise on T-cells in adult male Wistar rats. The T-cell populations were compared in sedentary rats (C, n = 5) and in rats trained for 4 weeks on a treadmill (30-60 min.day-1, 6 days.week-1, 20-30 m.min-1) and sacrificed at rest (T-rest, n = 5). In the T-rest rats, there were higher percentages of CD4+CD8-, CD4-CD8+ and CD4-CD8- thymocytes (P < 0.05, P < 0.05 and P < 0.01 respectively) and of CD4-CD8+ splenocytes (P < 0.01), and a lower percentage of CD4-CD8+ cells in the lymph nodes (P < 0.01). Compared with T-rest or C rats, trained rats (n = 5) or untrained rats (n = 5) sacrificed immediately after a running session (60 min, 30 m.min-1) had a higher percentage of mononucleated cells CD4+CD8- in the blood (P < 0.05 and P < 0.01). Lastly, compared with C rats, rats (n = 5) sacrificed immediately after their 5th day of training (30-60 min.day-1) presented a higher total splenocyte population (P < 0.05) and greater in vitro production of T-cell growth factor (interleukin 2 + Interleukin 4) by splenocytes in response to a mitogen (P < 0.01). These results would indicate that moderate endurance training modifies the cellular composition of lymphoid organs, without impairing the in vitro functions of T-cells.

Animals↗
PubMed1992

Glycogen depletion and resynthesis in the rat after downhill running.

To study the effect of downhill running on glycogen metabolism, 94 rats were exercised by running for 3 h on the level or down an 18 degrees incline. Muscle and liver glycogen concentrations were measured before exercise and 0, 48 and 52 h postexercise. Rats were not fed during the first 48 h of recovery but ingested a glucose solution 48 h postexercise. Downhill running depleted glycogen in the soleus muscle and liver significantly more than level running (P less than 0.01). The amount of glycogen resynthesized in the soleus muscle and liver in fasting or nonfasting rats was not altered significantly by downhill running (P greater than 0.05). On every day of recovery the rats were injected with dexamethasone, which induced similar increases in glycogen concentration in the soleus muscle and liver after the 52nd h of the postexercise period in the case of downhill and level running. The glycogen depletion and repletion results indicated that, under our experimental conditions, downhill running in the rat, a known model of eccentric exercise, affected muscle glycogen metabolism differently from eccentric cycling in humans.

Animals↗
PubMed1992

Lactate transport during differentiation of skeletal muscle cells: evidence for a specific carrier in L6 myotubes.

Cellular uptake of lactate involves a carrier in numerous types of mammalian cells. In cultured rat L6 myoblasts, lactate diffuses freely. We show that during myogenesis a carrier appears at the myotube stage. The degree of cellular differentiation was determined by microscopic observation and by measurement of a marker of biochemical differentiation: the increase in specific activity of creatine kinases.

Animals↗
PubMed1991

The energy cost of running increases with the distance covered.

The net energy cost of running per unit of body mass and distance (Cr, ml O2.kg-1.km-1) was determined on ten amateur runners before and immediately after running 15, 32 or 42 km on an indoor track at a constant speed. The Cr was determined on a treadmill at the same speed and each run was performed twice. The average value of Cr, as determined before the runs, amounted to 174.9 ml O2.kg-1.km-1, SD 13.7. After 15 km, Cr was not significantly different, whereas it had increased significantly after 32 or 42 km, the increase ranging from 0.20 to 0.31 ml O2.kg-1.km-1 per km of distance (D). However, Cr before the runs decreased, albeit at a progressively smaller rate, with the number of trials (N), indicating an habituation effect (H) to treadmill running. The effects of D alone were determined assuming that Cr increased linearly with D, whereas H decreased exponentially with increasing N, i.e. Cr = Cr0 + a D + He-bN. The Cr0, the "true" energy cost of running in nonfatigued subjects accustomed to treadmill running, was assumed to be equal to the average value of Cr before the run for N equal to or greater than 7 (171.1 ml O2.kg-1.km-1, SD 12.7; n = 30).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Splenic immunomodulation with swimming-induced stress in rats.

In order to determine the effects of swimming-induced stress, young male Wistar rats swam for a single session of 2 h duration, or for one 2-h session a day for five consecutive days. The absolute number of splenic mononuclear cells and the in vitro proliferation of mitogen-stimulated (PHA) T lymphocytes were studied. A single swimming session did not significantly diminish the number of splenic mononuclear cells, but it did significantly reduce splenic T-lymphocyte proliferation. This effect on T-lymphocyte proliferation was significantly blocked, in part, by subcutaneous injection of naltrexone before a swimming session. It was not significantly blocked by pre-exercise oral administration of aminoglutethimide. Repeated swimming sessions induced no significant changes in immune parameters. In conclusion, these data suggest that immunosuppression seen with a single swimming-induced stress period may partly be due to endogenous opioids, and that repetition of the swimming session reduced swimming-induced immunomodulation.

Aminoglutethimide↗
PubMed1991

Lactate transport in skeletal muscle cells: uptake in L6 myoblasts.

During exercise, lactate is produced by degradation of glucose-6-phosphate during glycolysis in the contracting muscles. This lactate is metabolized during and after exercise in the muscle itself and also in the liver and other muscles, which can use it as an energy metabolite or can resynthetize glycogen. Lactate is transported in the blood, and the rate of muscular utilization may be limited by two factors: the rate of metabolic utilization by the muscle cell; and the rate of transport across the membrane regulating lactate transfer from the blood to the cell. We have studied lactate uptake in L6 muscle cells by incorporation of 14C-lactate. The uptake rates were linear for 20 seconds with 5 mM lactate and 10 seconds with 20 mM. The uptake during 10 seconds for physiological lactate concentrations (1-20 mM) gave a straight line passing through the origin. Lactate uptake was not altered by specific inhibitors of lactate transport (2.5 mM alpha cyano-4-hydroxycinnamic acid. 5 microM 4,4'-diisothiocyanostilbene-2,2'disulphonic acid) or by the stereospecific D-lactate inhibitor. The results suggest that L-lactate uptake in L6 cells occurs by passive diffusion.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1991

Immunomodulations of thymocytes and splenocytes in trained rats.

The aim of this study was to describe the effects of training (running) on thymus and spleen cells in the rat. Young Wistar control rats (n = 6), rats trained for 4 wk (n = 5), and rats trained for 4 wk followed by 1 wk of intensive training (3 h/day, n = 6) were studied. Various lymphocyte surface and nuclear markers were determined by immunocytochemistry. The results show that 4 wk of training 1) decreased the percentage of bromodeoxyuridine (BrdU+) thymocytes (cell in phase S of the cycle, immature thymocytes; P less than 0.05) and the viability of thymocytes stimulated with concanavalin A (Con A; P less than 0.05) and 2) increased the absolute number of CD8+ (suppressor/cytotoxic T cells; 29%) and the percentage of CD8+ splenocytes (P less than 0.01). An additional week of intensive training in the 4-wk trained rats induced 1) a decrease in the absolute number of thymocytes (25%, P less than 0.05), TCR+ thymocytes, splenocytes (28%, P less than 0.01), T, CD4+ (helper T cells; 34%), and CD8+ (31%) splenocytes (P less than 0.01) and 2) an increase in the viability of splenocytes after stimulation with Con A for 72 h (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Blood mononuclear cells energy metabolism response to muscular exercise.

In a study of 4 enzymatic activities in human blood mononuclear cells before and immediately after standard maximal exercise test (25 min) on treadmill we noted: (1) a significant decrease in the activity of the pyruvate dehydrogenase complex (PDHc); (2) a significant increase in the activity of the citrate synthase (CS); and (3) no significant changes in the activities of cytochrome c oxydase and succinate cytochrome reductase. Although non-specifically stimulated (antigen or even mitogen), the blood mononuclear cells responded metabolically to muscular exercise. Pyruvate dehydrogenase (PDHc) activity of blood mononuclear cells appeared to decrease via enzyme interconversion regulation of PDHc. It is not known if these changes can be linked to the studies indicated altered immune function after a single bout of exercise.

Adult↗
PubMed1991

[Dystrophin expression in skeletal muscles in endurance-trained hypo-hyperthyroid and growth-hormone treated rats].

The aim of this study was to determine the effect of chronic muscular exercise, thyroid status and growth hormone administration on skeletal muscle dystrophin expression. Relative abundance of dystrophin (quantity in arbitrary units/50 micrograms of protein) was measured by immunoblotting and densimometry. Our results indicate that relative abundance of dystrophin in slow-or fast-twicht muscle was not modified by chronic muscular exercise (5 weeks), thyroxine administration (4 weeks), antithyroid drug treatment (6 weeks) or growth hormone administration (6 weeks).

Actinin↗
PubMed1990

Effect of previous supramaximal work on lacticaemia during supra-anaerobic threshold exercise.

Twelve male and female subjects (eight trained, four untrained) exercised for 30 min on a treadmill at an intensity of maximal O2 consumption (% VO2max) 90.0%, SD 4.7 greater than the anaerobic threshold of 4 mmol.l-1 (Than = 83.6% VO2max, SD 8.9). Time-dependent changes in blood lactate concentration [( lab]) during exercise occurred in two phases: the oxygen uptake (VO2) transient phase (from 0 to 4 min) and the VO2 steady-state phase (4-30 min). During the transient phase, [lab] increased markedly (1.30 mmol.l-1.min-1, SD (0.13). During the steady-state phase, [lab] increased slightly (0.02 mmol.l-1.min-1, SD 0.06) and when individual values were considered, it was seen that there were no time-dependent increases in [lab] in half of the subjects. Following hyperlacticaemia (8.8 mmol.l-1, SD 2.0) induced by a previous 2 min of supramaximal exercise (120% VO2max), [lab] decreased during the VO2 transient (-0.118 mmol.l-1.min-1, SD 0.209) and steady-state (-0.088 mmol.l-1.min-1, SD 0.103) phases of 30 min exercise (91.4% VO2max, SD 4.8). In conclusion, it was not possible from the Than to determine the maximal [lab] steady state for each subject. In addition, lactate accumulated during previous supramaximal exercise was eliminated during the VO2 transient phase of exercise performed at an intensity above the Than. This effect is probably largely explained by the reduction in oxygen deficit during the transient phase. Under these conditions, the time-course of changes in [lab] during the VO2 steady state was also affected.

Adult↗
PubMed1990

Changes in blood leucocyte populations induced by acute maximal and chronic submaximal exercise.

Absolute (x 10(3).mm-3) or relative (%) numbers of blood leucocyte types (monocytes, lymphocytes, neutrophils) and lymphocyte subsets (T11+, T4+, T8+, B1+, and NKH1+) reacting with specific monoclonal antibodies were determined at rest, immediately after maximal exercise on a treadmill, in six controls (C), and in six young cyclists before training (BT) and after 5 months of training (AT). Maximal exercise significantly increased the absolute number (mobilization) of virtually all the types of leucocytes and subsets of lymphocytes in C, BT and AT subjects. In these subjects mobilization of natural killer cells (NKH1+) and cytotoxic/suppressor T lymphocytes (T8+) was greater than mobilization of the other leucocyte types and lymphocyte subsets; however, maximal exercise induced no significant changes in the relative numbers of any leucocyte types and lymphocyte subsets, except in the case of T4+ lymphocytes in At cyclists. Chronic submaximal exercise induced increased mobilization of neutrophils and decreased mobilization of lymphocytes during maximal exercise, except in the case of B lymphocytes (B1+) and NKH1+ cells, and decreases in the absolute and relative number of neutrophils at rest. It remains to be seen how these results can explain the modifications of leucocyte activities noted in vitro after isolated or chronic exercise.

Adult↗
PubMed1990

Immunomodulations induced in rats by exercise on a treadmill.

Various regimens of treadmill exercise (0% slope) were used with rats: 60 min at 15 m/min (T-15), 180 min at 10 m/min (T-10), and 60 min/day at 15 m/min for 6 consecutive days (T-15-6). Exercise resulted in 1) decreases in the absolute number of mononuclear spleen cells in T-10 rats, 2) significant increases in in vitro splenic T-cell blastogenesis in response to phytohemagglutinin in T-10 rats, and 3) significant decreases in T-cell blastogenesis in T-15-6 rats. T-15-6 rats were given aminoglutethimide per os before exercise sessions to study the role of corticosteroids in the alteration of splenic T-cell blastogenesis. Aminoglutethimide significantly increased the T-cell blastogenesis in these T-15-6 rats compared with those not given aminoglutethimide, whereas it had no effect on immune parameters of sedentary rats. These results show that immunomodulations in the rat depend on the treadmill exercise regimen employed. If the mechanisms of the immunomodulation induced by isolated exercise of long duration are not elucidated, these data suggest that corticosteroids are involved in the alteration in T-cell blastogenesis induced by chronic muscular exercise.

Aminoglutethimide↗
PubMed1989

Blood lactate during submaximal exercises. Comparison between intermittent incremental exercises and isolated exercises.

Values of oxygen consumption, carbon dioxide production, ventilation and blood lactate concentration were determined in eight active male subjects during the minute following submaximal square-wave exercise on a treadmill under two sets of conditions. Square-wave exercise was (1) integrated in a series of intermittent incremental exercises of 4-min duration separated by 1-min rest periods; (2) isolated, of 4- and 12-min duration, and of intensity corresponding to each of the intermittent incremental periods of exercise. For square-wave exercise of the same duration (4 min) and intensity, no significant differences in the above-mentioned parameters were noted between intermittent incremental exercise and isolated exercise. Only at high work rate (greater than 92% maximal oxygen uptake), were blood lactate levels in three subjects slightly higher after 12-min of isolated exercise than after the 4-min periods of isolated exercise. Examination of these results suggests that (1) 80-90% of the blood lactate concentration observed under our experimental conditions results from the accumulation of lactate in the blood during the period of oxygen deficit; (2) therefore the blood lactate concentration/exercise intensity relationship, for the most part, appears to represent the lactate accumulated early in the periods of intermittent incremental exercise.

Adult↗
PubMed1985

Serum levels of insulin-like growth factor (IGF) and IGF binding protein in insulin-dependent diabetics during an episode of severe metabolic decompensation and the recovery phase.

Serum insulin-like growth factor (IGF) and IGF-binding protein (IGF BP) levels were determined in 13 insulin-dependent diabetic patients (30-60 yr of age) during an episode of severe metabolic decompensation and the recovery phase. After separation by acidic gel filtration, the samples were assayed for IGF using a protein-binding assay (which measures mainly IGF I-related peptides) and for IGF BP by measuring the binding activity, in both assays using IGF I as tracer. The reference standard was a pool of normal adult serum with an assigned potency of 1 U IGF and 1 U IGF BP per ml. The mean IGF level in the uncontrolled state, 0.55 +/- 0.05 (SEM) U/ml, was about half that of normal subjects (1.03 +/- 0.03 U/ml, P less than 0.001). With treatment, IGF levels reached the normal range within 3 days. The pattern of changes in IGF BP levels was roughly similar, although the values in the uncontrolled state were less depressed (0.78 +/- 0.04 U/ml vs. 0.98 +/- 0.04 in normal subjects, P less than 0.01). Highly significant correlations (P less than 0.001) were found between IGF levels and the biological parameters reflecting control of the diabetes: glycosuria (r = -0.60), glycemia (r = -0.52), ketonemia (r = -0.65), and HCO3- (r = 0.58). Similar but less significant correlations were found for IGF BP. The mean GH level during the period of metabolic decompensation (9.0 +/- 1.5 ng/ml) was elevated compared to that after recovery (2.9 +/- 0.8 ng/ml) (P less than 0.025). There was a negative correlation between GH values and IGF levels (r = -0.67, P less than 0.001). The correlation with IGF BP was much less significant (r = -0.38, P less than 0.05). The results clearly reflect the role of insulin and nutritional factors in the control of IGF levels. They also support the notion that the biosynthesis of IGF and IGF BP is not regulated in the same way.

Adult↗
PubMed1979

[Idiopathic hypercalciuria: effects of acute phosphorus deficiency (author's transl)].

Eleven patients with kidney stone disease and idiopathic hypercalciuria (urinary calcium above 4 mg/kg/j), without phosphorus renal leak and 6 control subjects have been put for 3 days on a diet containing 1 g calcium and 1 phosphorus daily (period A), and then for 4 days on a diet containing 1 g calcium, 450 mg phosphorus and 3 g aluminium hydroxyde daily (period B). During period A, no significant difference in blood calcium, phosphorus and magnesium, not in phosphaturia, rate of phosphorus reabsorption (RPR) and ratio maximum RPR/creatinine clearance was found between the two groups. After 2 days on a low phosphate diet (period B) the blood phosphorus decreased significantly in the hypercalciuric patients but not in the control subjects, thus revealing among the forme a latent abnormality in the retention of phosphates. This abnormality could play an important role in the pathogenesis of hypercalciuria.

Adult↗
PubMed1979

Systematic utilization of an antipseudomonas aeruginosa vaccine in a severe burn unit.

The biological and clinical results of vaccination against pseudomonas aeruginosa infection have been analyzed for a group of 287 burned patients having over 25% surface burnt. The vaccine used was a cellular one inactivated by heat and containing 10 different strains. The effectiveness has been judged on the one hand by the increase in the antipseudomonas antibody count and on the other by comparing a group of vaccinated patients with a non-vaccinated group. After vaccination, the antipseudomonas aeruginosa antibodies increased from the 4th-5th day and reached an impressive increase after the 10th day. Clinically, protection is almost complete if one considers that pseudomonas aeruginosa positive blood cultures appear 15 days after vaccination, and above all the prognosis of these late infections. Both locally and generally, this vaccine has always been perfectly tolerated.

Antibodies, Bacterial↗