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Biomedical subjects

J M Crielaard

Publications and source records attributed to J M Crielaard.

At least 19 recordsLinked to original sources
PubMed2000

Spatial distribution of blood flow in electrically stimulated human muscle: a positron emission tomography study.

Neuromuscular electrical stimulation (NMES) was studied with positron emission tomography (PET) and H(2)(15)O in the quadriceps muscle of 11 men. The subjects were submitted to simultaneous bilateral isometric contraction (5 s)-rest (5 s) cycles for 12 min, with a workload corresponding to 5% of quadriceps maximal isometric voluntary torque (QMIVT) for one thigh (5%T) and 10% of QMIVT for the other (10%T). Scans were centered at the electrodes and tissue blood flow (TBF) was evaluated in square regions of interest (ROIs) (3.5 cm(2)) in the transverse section (TS) of both thighs. The mean TBF reached 8.9 mL min(-1) 100 g(-1) in the TS of the 5%T and 11.5 mL min(-1) 100 g(-1) in the TS of the 10%T (P > 0.05). A negative linear relationship was found for both thighs between the ROI-electrode distance and the TBF (P </= 0.009). The mean percentage of activated ROIs (TBF > 5 mL min(-1) 100 g(-1)) was lower in the 5%T than in the 10%T (50.6% vs. 62.2%; P = 0.017). With NMES, the pattern of spatial recruitment appears linked to electrode proximity and is spatially extended. These results confirm the utility of combining NMES with voluntary exercise in the treatment of atrophied muscle.

Adult↗
PubMed1999

Effects of training on exercise-induced muscle damage and interleukin 6 production.

To address the question of whether the increased plasma concentration of interleukin 6 (IL-6) following strenuous muscular work could be related to exercise-induced muscle damage, 5 moderately active male volunteers underwent two isokinetic exercise sessions in the eccentric mode, separated by a period of 3 weeks during which the subjects underwent five training sessions. Before training, exercise was followed by severe muscle pain (delayed-onset muscle soreness; DOMS), and by significant increases in plasma IL-6 level and serum myoglobin concentration (SMb) (P < 0.001). After training, postexercise DOMS and SMb values were significantly lower than those measured before training. There was no significant difference between plasma IL-6 levels measured at the same time points before and after training. We conclude that the hypothetical relationship between exercise-induced muscle damage and increased postexercise levels of circulating IL-6 is not substantiated by the present results.

Adult↗
PubMed1999

Human muscle energetics during voluntary and electrically induced isometric contractions as measured by 31P NMR spectroscopy.

Electrical stimulation (ES) and voluntary contraction (VC) were compared in the quadriceps muscle of ten male volunteers. In both modes, a workload corresponding to 20% of maximal voluntary contraction was applied during 64 isometric contraction (5.5 s)-relaxation (5.5 s) cycles. The protocols were performed in a 1.5 T whole-body magnet. The Pi/PCr ratio and the intracellular pH (pHi) were monitored by 31P NMR spectroscopy during baseline, exercise and recovery periods, in a superficial region of the vastus medialis. During baseline, the Pi/PCr ratio (0.12 vs. 0.10) and the pHi (7.01 vs. 7.00) were comparable in both conditions. During exercise, the Pi/PCr ratio was higher (0.36 vs. 0.14) and the pHi was lower (6.85 vs. 7.07) during ES than during VC. For the same external work production, these results reflect a different metabolic solicitation in the ES quadriceps than in the VC ones.

Adult↗
PubMed1999

[Osteoarticular hemochromatosis].

Idiopathic hemochromatosis is one of the most common adult genetic disorders in the Caucasian population. The clinical manifestations are various with hepatic, pancreatic, cardiac disorders.... Arthritis associated with idiopathic hemochromatosis are less well-known and differential diagnosis with other arthropathies is sometimes difficult. Early diagnosis enables rapid treatment and better prognosis.

Adult↗
PubMed1998

Nitric oxide downregulates interleukin 1beta (IL-1beta) stimulated IL-6, IL-8, and prostaglandin E2 production by human chondrocytes.

OBJECTIVE: To investigate the effects of endogenously produced nitric oxide (NO) on interleukin 6 (IL-6), IL-8, prostaglandin E2 (PGE2), and proteoglycan production by human chondrocytes. METHODS: Human articular chondrocytes were isolated from their extracellular matrix by triple successive enzymatic digestion of the cartilage and cultured 48 h in a well defined culture medium. IL-6 and IL-8 were directly assayed into culture media by specific enzyme amplified sensitivity immunoassays. Proteoglycans and PGE2 were quantified by specific radioimmunoassays. Cell culture media were assayed for NO2 using a spectrophotometric assay based upon the Griess reaction. RESULTS: Unstimulated chondrocytes produced low levels of NO, IL-6, IL-8, and PGE2. Production was significantly stimulated by IL-1beta and lipopolysaccharide (LPS). As well, proteoglycan synthesis was profoundly inhibited by IL-1beta and LPS. Inhibition of NO synthesis with the competitive inhibitor NG-monomethyl-L-arginine (L-NMMA) led to enhancement of IL-6, IL-8, and PGE2 production stimulated by either IL-1beta alone or in combination with LPS, whereas the inhibition of proteoglycan production by IL-1beta was not modified by L-NMMA. CONCLUSION: LPS and IL-1beta stimulated IL-6, IL-8, and PGE2 production are downregulated by endogenously produced NO, which could limit the inflammatory reaction occurring in arthritis.

Adult↗
PubMed1997

Sciatic nerve regeneration through venous or nervous grafts in the rat.

This study analyses the interest of isologous venous grafts filled with saline or with Schwann cells versus nerve grafts as guides for regeneration of the sciatic nerve in 35 Wistar rats. Electrophysiological parameters (conduction velocities and distal latencies of motor responses) and the functional index of De Medinacelli were measured several times from 1 month to 1 year after surgery. An histological analysis was performed on 2 control rats and on 3 rats killed 6 or 12 months after surgery: the total number of fibers was counted on a montage photoprint of the whole nerve, and the diameters of axons and the thickness of the myelin sheath were measured on digitized images. With a portion of nerve as guide, the regeneration is faster than with a vein. However, regeneration after 6 months is at least as good with a venous graft filled with Schwann cells, as assessed by electrophysiological, functional, and histological analysis. The addition of Schwann cells in grafted veins allows the nerve to regenerate through longer gaps than previously described (25 vs 15 mm). In order to assess the quality of nerve regeneration, functional, electrophysiological, and histological analysis are complementary.

Animals↗
PubMed1996

Myocellular enzyme leakage, polymorphonuclear neutrophil activation and delayed onset muscle soreness induced by isokinetic eccentric exercise.

To address the question of whether delayed onset muscular soreness (DOMS) following intense eccentric muscle contraction could be due to increased production of the arachidonic acid derived product prostaglandin E2 (PGE2). 10 healthy male subjects were submitted to eccentric and concentric isokinetic exercises on a Kin Trex device at 60 degrees/s angular velocity. Exercise consisted of 8 stages of 5 maximal contractions of the knee extensor and flexor muscle groups of both legs separated by 1 min rest phases. There was an interval of at least 30 days between eccentric and concentric testing, and the order of the two exercise sessions was randomly assigned. The subjective presence and intensity of DOMS was evaluated using a visual analogue scale, immediately, following 24 h and 48 h after each test. Five blood samples were drawn from an antecubital vein: at rest before exercise, immediately after, after 30 min recovery, 24 h and 48 h after the tests. The magnitude of the acute inflammatory response to exercise was assessed by measuring plasma levels of polymorphonuclear elastase ([EL]), myeloperoxidase ([MPO]) and PGE2 ([PGE2]). Using two way analysis of variance, it appeared that only eccentric exercise significantly increased [EL] and DOMS, especially of the hamstring muscles. Furthermore, a significant decrease in eccentric peak torque of this muscle group only was observed on day 2 after eccentric work (- 21%; P < 0.002). Serum activity of creatine kinase and serum concentration of myoglobin increased significantly 24 and 48 h after both exercise tests. However, these variables reached significantly higher values following eccentric contractions 48 h after exercise. Mean [PGE2] in the two exercise modes remained unchanged over time and were practically equal at each time point. On the basis of these findings, we conclude that the magnitude of polymorphonuclear (PMN) activation, muscle damage, and DOMS are greater after eccentric than after concentric muscle contractions. However, the hypothesized interplay between muscle damage, increased PGE2 production, DOMS sensations, and reduced isokinetic muscle performance was not substantiated by the present results.

Adult↗
PubMed1996

Mechanical properties of skin in recombinant human growth factor abusers among adult bodybuilders.

A Cutometer was used to measure the mechanical properties of skin in 8 adult bodybuilders who were recombinant human growth hormone (hGH) abusers. Although skin deformability and biological elasticity remained within the normal range, an increase in dermal viscosity was noted. The expression of the activity of hGH or insulin-like growth factor I on target dermal cells is likely to be responsible for these findings.

Adult↗
PubMed1987

Comparative study of high bio-availability glaphenine and paracetamol in cervical and lumbar arthrosis.

Seventy-eight patients, 40 suffering from cervical arthrosis and 38 from lumbar arthrosis, received for a period of two weeks paracetamol or a new preparation of glaphenine, in a double blind study. The two drugs were found to have the same efficiency on the subjective parameters but high bioavailability glaphenine seems to have an effectiveness in the range of articulatory movements, which is not found with paracetamol. The side effects were quite equivalent.

Acetaminophen↗
PubMed1987

Bone mineral content and physical activity.

The purpose of this study was to estimate the effects of intense and regular physical activity on locomotor system modifications. Tennis, with its unilateral solicitations, allows a more precise examination of specific localized development. Ten professional tennis players were compared with sedentary age-matched students. Muscular modifications were observed, mainly in the forearm circumference. The dominant side forearm circumference was 13% larger than the opposite side. Asymmetry was less in the upper arm and insignificant in the thorax and vertebra. Deep modifications in bone mineral content (BMC) were investigated by isotopic techniques, based on differential photon attenuation in bone and soft tissue of the forearm. Bone density was markedly increased in professional tennis players. Even in the nondominant side, radius BMC was 1.18 g HA/cm, 15% higher than in sedentary control students. The difference was yet larger in the dominant mid-radius, reaching 1.47 g HA/cm. The same differences were observed for the ulna and involved both cortical and trabecular bone. In the control group of sedentary students, no significant difference was noted between the two upper limbs. This study clearly demonstrates the positive correlation between exercise and bone mineralization. The precise mechanical constraints optimizing the favorable effect in the most efficient way should be studied.

Adult↗