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Biomedical subjects

C Cornu

Publications and source records attributed to C Cornu.

At least 19 recordsLinked to original sources
PubMed2006

Power responses of a rowing ergometer: mechanical sensors vs. Concept2 measurement system.

The aim of this study was to compare the power provided by a recent ergometer with the power developed by the rower determined using mechanical sensors set on the same apparatus. Six rowers and six non-rowers performed a power graded test and an all-out start on an instrumented ergometer (Concept2 system, model D, Morrisville, VT, USA). Power values displayed by the ergometer were recorded with a specific software. A strain gauge placed near the handle and a position sensor installed on the chain allowed the calculation of the power developed by the rower. Power values provided by the ergometer were strongly correlated to those determined with a direct measurement and calculation of power. However, power values given by the Concept2 system were lower (- 17.4 to - 72.4 W) than those calculated using mechanical sensors. This difference in power measurements was lower at a steady pace and for rowers. The Concept2 system underestimates the power produced by the rower by approximately 25 W. This difference in power seems to be independent of the level of power developed but increases with variations in intensity and pace. The deletion of the first strokes following changes in power production allows to limit this phenomenon. According to the use of the power parameter in the experimental design, it could be appropriate to correct values provided by the Concept2 ergometer.

Adult↗
PubMed2005

[Readability of informed consent forms for subjects participating in biomedical research: updating is required].

OBJECTIVE: We compared informed consent forms of subjects participating in biomedical research with those of references texts in order to determine the factors that influence readability. METHODS: We assessed the readability of 73 informed consent forms of research protocols conducted in the clinical investigation centres in the Rhone-Alpes area, and then compared them with 33 reference texts corresponding to 5 French school grades (first year infant, primary school, GCS level, high school, and classics aggregation), using the Flesch test and Cordial" analyser. RESULTS: Median Flesch scores were 66 for the first year infant level, 62 for the primary school level, 58 for the GCS level, 42 for the high school level, and 43 for the aggregation level. It was 22 for the informed consent forms. Median Cordial scores were 86 for the first year infant level, 77 for the second, 74 for the third, 49 for the fourth, 43 for the fifth. It was 1 for the informed consent forms. No methodological factor correlated with Flesch and Cordial" results. CONCLUSION: The quantitative readability scores for informed consent forms for subjects participating in biomedical research are low, lower than those proposed to aggregation candidates, whatever the type of protocol. Some thought must be given to the impact of the reduced readability on patients' understanding, and steps should be taken to improve the readability of the forms.

Adolescent↗
PubMed2003

Muscle elastic properties during wrist flexion and extension in healthy sedentary subjects and volley-ball players.

The aim of this study was to determine the effects of gender and chronic hyperactivity (training) on musculo-tendinous stiffness and joint flexibility and to examine in vivo whether those stiffness parameters were correlated. Thus, maximal isometric voluntary contraction, series elastic stiffness during wrist flexion and wrist extension, and wrist flexibility were investigated in healthy sedentary subjects and in women volley-ball players. Maximal isometric contraction and flexibility were measured classically with specific ergometers. Moreover, muscle stiffness measurements were performed thanks to the use of quick-release movements of the wrist, which had previously been maintained in isometric contraction, allowing the calculation of a musculo-tendinous stiffness index. Despite significant differences in maximal voluntary contraction between wrist flexors and wrist extensors for each of the groups tested and between men and women, no significant gender, function or training effects were found upon musculo-tendinous stiffness indices. Flexibility assessments in both women groups demonstrated that active to passive ratios for wrist flexion remain unchanged whereas a significant training-induced increase for wrist extension was observed. Moreover, no significant relationship between women active joint flexibility and musculo-tendinous stiffness indices was found (r(2): 0.0004 - 0.0319, p > 0.05) whatever the muscle function tested. Collectively, the present results suggest that neural factors rather than morphological changes (i. e. muscle architecture and fiber composition) may explain predominantly the functional consequences observed in wrist extension associated with volley-ball training. Moreover, both musculo-tendinous stiffness and joint flexibility give different information about wrist functional status.

Adult↗
PubMed2003

The effects of exercise and protein-energy supplements on body composition and muscle function in frail elderly individuals: a long-term controlled randomised study.

Fighting against inactivity and inadequate nutritional intake are of utmost importance in the elderly. To our knowledge, the few studies which have been performed were conducted for only a short period and the results do not permit formal conclusions to be drawn. We therefore tried to fill this gap in our knowledge by determining whether an intervention combining an acceptable progressive exercise programme and nutritional supplements would be feasible for a long-term period in the very frail elderly, and would bring about concomitant benefits in body composition and muscle power. Accordingly, this exercise and nutritional combination was assessed in the frail elderly in a 9-month randomised trial with a factorial design. Fifty-seven elderly volunteers over 72 years, from sixteen retirement homes in Lyon, France participated in the study. Dietary supplements were compared with placebo, and physical exercise was compared with memory training. Main outcome measures were fat-free mass (FFM) and muscle power. FFM was determined by labelled water, and muscle power was measured by a leg-extensor machine. At 9 months, the compliance was 63 % for exercise sessions, and 54 % for nutritional supplements. In patients with dietary supplements, muscle power increased by 57 % at 3 months (P=0.03), and showed only a tendency at 9 months; although FFM increased by 2.7 % at 9 months, the difference was not significant (P=0.10). Exercise did not improve muscle power at 9 months, but improved functional tests (five-time-chair rise, P=0.01). BMI increased with supplements (+3.65 %), but decreased with placebo (-0.5 %) at 9 months (P=0.007). A long-term combined intervention is feasible in frail elderly individuals with a good rate of compliance. Nutritional supplements and exercise may improve muscle function. Despite no significant results on FFM, due to the limited number of volunteers, combined intervention should be suggested to counteract muscle weakness in the frail elderly.

Aged↗
PubMed2002

[Total knee arthroplasty: reproducibility of gait speed].

OBJECTIVE: To calculate the inter-session (test-retest) and inter-observers' reproducibility of the maximal gait speed measured in patients recently operated for osteoarthritis with a total knee arthroplasty. METHODS: Evaluation of the maximal gait speed in 20 patients [t72 +/- 6.5 years] on a 10-meter track by two observers using a manual stopwatch and by an automatic photoelectric stopwatch. The maximal gait speed was measured from three trials in two conditions, with and without crutches, with 1 day of interval at the third and the fourth post-surgery week. RESULTS: The inter-session reproducibility (1-day test-retest) is 0.91 [intraclass correlation coefficient] with crutches and 0.9 without crutches at the third post-surgery week, and 0.96 and 0.94 at the fourth post-surgery week with and without crutches respectively. The inter-observers' reproducibility is 0.9 to 0.99. CONCLUSION: When a standardized protocol is used, the reproducibility of maximal gait speed measurements is excellent. These tests evaluate easily and objectively the maximal gait speed in patients recently operated with a total knee arthroplasty.

Aged↗
PubMed2001

Efficacy of pneumococcal polysaccharide vaccine in immunocompetent adults: a meta-analysis of randomized trials.

The use of pneumococcal polysaccharide vaccine (PPV) is low in some countries, maybe because of doubts regarding its efficacy. This meta-analysis aims at combining evidence from randomized trials of PPV assessing its efficacy in preventing Streptococcus pneumoniae related diseases in immunocompetent adults. In the fourteen trials totalling 48,837 patients retrieved, PPV prevents definite pneumococcal pneumonia by 71%, presumptive pneumococcal pneumonia by 40%, and mortality due to pneumonia by 32%, but not all-cause pneumonia or death. No preventive effect was seen in the subgroup of patients aged 55 years or more, possibly due to a lack of statistical power.

Adult↗
PubMed2001

Muscle and joint elastic properties during elbow flexion in Duchenne muscular dystrophy.

1. Maximal voluntary contraction (MVC), series elastic stiffness and total joint stiffness during elbow flexion were investigated in healthy boys and in boys with Duchenne muscular dystrophy (DMD) in order to assess changes in mechanical properties induced by the disease. 2. Two methods were used to perform stiffness measurements: (i) the application of sinusoidal perturbations to the joint during flexion efforts, allowing the calculation of total joint stiffness; (ii) the use of quick-release movements of the elbow, which had previously been maintained in isometric contraction, allowing the calculation of series elastic stiffness. In each case, stiffness was linearly related to torque, leading to the calculation of a normalized stiffness index as the slope of this stiffness-torque relationship. 3. As expected, mean MVC was found to be much higher for healthy boys (20.02 +/- 5.20 N m) than for DMD patients (3.09 +/- 2.44 N m). Furthermore, the results showed that it was possible to characterize healthy and DMD children by virtue of the mechanical properties measured. Mean series elastic stiffness index was higher for DMD children (142.55 +/- 136.58 rad(-1)) than for healthy subjects (4.39 +/- 2.53 rad(-1)). The same holds for mean total joint stiffness index: 43.68 +/- 67.58 rad(-1) for DMD children and 2.26 +/- 0.70 rad(-1) for healthy subjects. In addition, increases in stiffness were more marked in DMD patients exhibiting high levels of muscle weakness. 4. These changes are interpreted in terms of the adaptation of the properties of the muscles and joint involved, i.e. muscle fibres, tendons, peri- and intra-articular structures.

Adolescent↗
PubMed2001

Musculo-tendinous and joint elastic characteristics during elbow flexion in children.

OBJECTIVE: The aim of the present research was to determine joint stiffness and musculo-tendinous stiffness in children. BACKGROUND: No reliable data was available on differences in such parameters when comparing children and adults. METHODS: Sinusoidal perturbations and quick-released movements were applied to the right elbow during flexion to determine joint stiffness and musculo-tendinous stiffness, respectively. For normalization purposes, stiffness indexes were calculated as the slope of the relationship between stiffness and torque. RESULTS: Main results were that musculo-tendinous stiffness indexes obtained in children were similar to adult data deduced from the literature. On the other hand, joint stiffness indexes obtained in children were in the range 0.9-3.8 rad(-1) and were lower than those reported in the literature for adults (between 4 and 8.5 rad(-1)). CONCLUSION: Since normalized musculo-tendinous stiffness is similar in children and in adults, it can be hypothesized that, during growth, increase in ability to produce force parallels elastic tissue development. RELEVANCE: Stiffness parameters could be used, in the context of other functional tests, to characterize changes in muscle properties in neuromuscular disorders when elastic tissues are supposed to be altered.

Adolescent↗
PubMed2001

Thrombolytic therapy for acute ischemic stroke.

Available evidence of thrombolysis in acute ischemic stroke comes from a series of recent trials conducted in patients with acute stroke, and from a meta-analysis published in the Cochrane Library. The objective of this paper is to review the literature on tolerability and efficacy of thrombolytic therapy in patients with acute ischemic stroke, to find out what the level of evidence is for each thrombolytic drug, and what should consequently be done in the routine practice. This review is based on a bibliographic search of published meta-analyses of randomized trials, published randomized trials, and ongoing randomized trials, with the outcomes of disability, death, and symptomatic intracerebral hemorrhages (fatal or non-fatal). Our primary end-point is a combination of death and disability, in terms of "death or dependency", with dependency defined as a modified Rankin Score (mRS) of >/=3. The level of evidence for the efficacy of a thrombolytic treatment is considered sufficient if there is both a statistically significant effect in the meta-analysis of all randomized trials, without statistically significant heterogeneity, together with one adequately powered and designed conclusive trial. Streptokinase has a clearly harmful effect, without any demonstrated benefit and must not be used in patients with acute ischemic stroke. The level of evidence of an effect of intra-arterial pro-urokinase to reduce death or dependency is low, available data are sparse (only 220 patients), the estimation of its real efficacy and tolerability remains unclear, and its use in clinical practice is not presently justified. The efficacy of alteplase has been incompletely demonstrated because the results vary across trials and type of outcomes (death, death or dependency), and the cut-off of the disability scale. There is a significant heterogeneity in the effect on death or dependency. However, we can conclude that there is a beneficial effect, but its clinical application is limited because of the absence of adequate criteria to identify patients most likely to benefit from treatment. Overall the use of alteplase in patients with acute stroke was associated with some benefit, but it significantly increased total mortality in two trials. Given the observed confidence interval (CI), the results are compatible with, in the best situtation, 203 advoided death or dependency and 61 avoided death per 1000 treated patients, and at worst 77 avoided death or dependency and 38 extra deaths per 1000 treated patients. Further trials aimed at validating more discriminant selection criteria are mandatory.

Acute Disease↗
PubMed2000

Postmenopause hormone treatment in women with NIDDM or impaired glucose tolerance: the MEDIA randomized clinical trial.

OBJECTIVE: To assess the biological safety of four hormone replacement treatment (HRT) combinations in women with non insulin dependent diabetes mellitus (NIDDM) or impaired glucose tolerance (IGT). SUBJECTS AND METHODS: Randomized, double-blind, placebo-controlled trial to analyze the variation of fibrinogen, factor VII, PAI1, and TG blood levels in women (n=99), with NIDDM or IGT, receiving a 3-month course of either oral oestradiol (1 or 2 mg) combined with Chlormadinone Acetate 5 mg, or transdermal oestradiol 50 microg/24 h in association with Norethisterone Acetate (11.2 or 22.4 mg), or placebo. Follow-up lasted 3 months. RESULTS: Ninety nine patients, mean age 56 years (SD 5), mean diabetes duration 7 years (S.D. 7), mean glycated hemoglobin (7.3%) were enrolled. There was no significant difference between the groups for any of the primary hemostasis criteria (n=77). Triglycerides (TG) variation significantly differed between groups, P=0.01, from -21% in the large patch group, to +22% in the placebo group (n=82). Treatment administration routes did not significantly differ for any of the criteria. There was a significant difference in the total cholesterol variation between groups, from +8.7% in the placebo group to -10.8% in the oral 1 mg group (P=0.001). CONCLUSION: The treatments had no highly deleterious effect in these patients with NIDDM or with IGT. Long-term trials can be performed with such patients, and an hormone treatment can be prescribed to relieve symptoms. Since these patients had a well-controlled NIDDM, results might be different in less well-controlled diabetes. The data do not support the hypothesis of an impaired oestrogen effect in patients with NIDDM.

Biomarkers↗
PubMed2000

Streptokinase in acute ischemic stroke: an individual patient data meta-analysis : The Thrombolysis in Acute Stroke Pooling Project.

BACKGROUND AND PURPOSE: Three major randomized controlled trials of streptokinase in acute ischemic stroke were curtailed because of safety concerns. The prospective Thrombolysis in Acute Stroke Pooling Project (TAS-PP) was established to examine the aggregate data to identify factors influencing the effect of streptokinase. METHODS: Individual patient data from the Australian Streptokinase Trial (ASK), Multicentre Acute Stroke Trial-Europe (MAST-E), Multicentre Acute Stroke Trial-Italy (MAST-I), and Glasgow Trial (Glasgow) were pooled. Multivariate modeling determined the interaction between treatment effect and delay from symptom onset to treatment, predicted baseline risk, age, concomitant aspirin or heparin use, and the presence of early CT signs on the outcomes of 10-day death, death and disability, or death alone at 3 or 6 months. RESULTS: Patients' records were pooled (total 1292 patients; streptokinase, n=653, no streptokinase n=639). The subgroup analysis of treatment effect according to delay from symptoms to inclusion shows only a trend toward a better treatment effect with shorter delay, which is not statistically significant for any outcome. Heavier patients in MAST-E may have had a lower (non significant) risk from the fixed dose of 1.5 million units of streptokinase. Concomitant aspirin increased the excess mortality rates in streptokinase-treated patients (17% without aspirin versus 91% with aspirin, P=0.005). The presence of early CT scan signs did not increase the detrimental effect of streptokinase. CONCLUSIONS: Few factors influenced the response to streptokinase. However, earlier administration, lower doses of streptokinase, and avoidance of concomitant aspirin should be considered if further streptokinase trials in acute stroke are planned.

Acute Disease↗
PubMed1999

Viscous properties of human muscle during contraction.

The purpose of this study was to determine viscous properties of human muscle during plantarflexion efforts. Experiments were performed on 17 subjects with an ankle ergometer allowing sinusoidal oscillations during isometric contractions and isokinetic movements. Sinusoidal oscillations led to the expression of (i) Bode diagrams of the musculo-articular system allowing the determination of a damping coefficient (Bbode); and (ii) a viscous coefficient (Bsin) using an adaptation of Hill's equation to sinusoidal oscillations. Isokinetic movements led to torque-velocity relationships. They showed a fall in torque associated to an increase in angular velocity what was quantified by calculating a damping coefficient (Biso). Both experiments gave consistent results indicating that Bbode was the lowest viscous parameter. This difference is discussed in terms of (i) "analog" viscosity originating from muscle cross-bridges; and (ii) real mechanical damping of passive structures.

Adult↗
PubMed1999

Liver transplantation and HBsAg-positive postnecrotic cirrhosis: adequate immunoprophylaxis and delta virus co-infection as the significant determinants of long-term prognosis.

BACKGROUND/AIMS: The place of liver transplantation in hepatitis B viral (HBV)-related diseases remains controversial because of the high rate of reinfection. The aim of this study was to define the determinants of long-term prognosis after transplantation. METHODS: Fifty-eight patients were transplanted during the period February 1984-September 1996. Six patients died during the early (< 3 months) posttransplant period from causes unrelated to HBV infection. All 52 long-term (> 3 months) survivors were evaluated in relation to the mode of presentation, viral replication at time of transplantation, absence of hepatocellular cancer at time of transplantation and use of adequate immunoprophylaxis (IP). Adequate immunoprophylaxis, defined as maintenance of anti-HBs levels over 100 mUI/ml, was introduced in December 1989. Intention-to-treat IP analysis compared patients transplanted before and after this date. The median follow-up was 74 months (range 4 to 131). Forty-seven patients (90%) had a minimal follow-up of 3 years. RESULTS: Five-year actuarial survival rates of 58 patients and of 52 long-term survivors were 72 +/- 6% and 80 +/- 6%, respectively. Univariate analysis showed that delta co-infection (n = 25) significantly improved survival (p < 0.001) [96 +/- 4% vs 63 +/- 10% in HBV patients (n = 27) at 5 years] as did absence of hepatocellular cancer (n = 36) (p = 0.020) [89 +/- 5% vs 61 +/- 12% in 16 non-cancer patients]. IP, however, significantly influenced 5-year survival in the HBV-patient group (n = 17) (p = 0.001) [85 +/- 10% vs 30 +/- 14% in 10 patients without IP). Multivariate analysis selected delta co-infection (p = 0.002) and IP (p = 0.01) as the significant determinants of prognosis independently influencing survival. Uni- and multivariate analyses showed that survival without reinfection was significantly influenced by IP (p = 0.002) [73 +/- 8% (n = 31) versus 33 +/- 12% in 15 non-treated patients). CONCLUSIONS: Delta virus co-infection and immunoprophylaxis are the most important prognostic factors after transplantation for postnecrotic HBsAg-positive cirrhosis. Transplantation can be proposed as a therapeutic tool only if life-long adequate adjuvant therapy can be achieved. Under this condition good results can even be obtained if there is viral replication at the time of transplantation.

Actuarial Analysis↗
PubMed1999

Thrombolysis in Acute Stroke Pooling Project: a meta-analysis on individual patient data.

To assess the efficacy and safety of thrombolytic therapy in acute ischaemic stroke, randomised clinical trials have been undertaken. Their results suggest that further research should be attempted to identify patients for whom the benefit/risk ratio of thrombolysis is beneficial. The Thrombolysis in Acute Stroke Pooling Project (TAS-PP) group will pool individual patient data from recent studies and meta-analyse these. A Steering Committee drafted the protocol and defined access rules to the common file. The objectives are to assess the efficacy of thrombolysis to reduce death or severe disability, to identify predictors of death and haemorrhagic transformation, and to identify subgroups with a better response to treatment, using logistic regression, survival curve comparison (log rank test), multivariate modelling (with treatment, baseline characteristics, delay from symptom to treatment as covariates). This project will help defining subpopulations that are more likely to benefit from this treatment, which cannot be achieved using tabulated data, and designing future trials. Copyright 1999 Harcourt Publishers Ltd.

Journal Article↗
PubMed1999

Apnea syndrome in a patient with Alzheimer dementia under chlormethiazole treatment: a clinical experience report.

Sleep apnea syndromes in conjunction with dementia have attracted considerable interest among geropsychiatrists in recent years. This clinical case report describes a demented and delirious elderly patient with a history of alcoholism who developed a sleep apnea syndrome under treatment with chlormethiazole. The risk of chlormethiazole treatment may be underestimated in vulnerable patients, e.g. those suffering from severe respiratory diseases or dementia. Alternative treatments for delirious states need to be evaluated instead.

Aged↗
PubMed1999

Hemorrhagic transformation in acute ischemic stroke. The MAST-E study. MAST-E Group.

BACKGROUND AND PURPOSE: Hemorrhagic transformation (HT) is the most critical complication of thrombolytics in clinical trials in acute stroke. The aim of this study was to determine the rates and the predictors of HT in the Multicenter Acute Stroke Trial-Europe (MAST-E) study. METHODS: We performed a post hoc analysis of MAST-E data designed to assess the safety and efficacy of streptokinase administered intravenously within 6 hours of stroke onset. HT included all intracerebral hemorrhages and symptomatic hemorrhages (SHT) associated with clinical worsening. The predictors of HT and SHT were determined using multivariate modeling. RESULTS: Among the 310 patients included, 159 patients had HT and 37 SHT (97 and 33 in the streptokinase group and 62 and 4 in the placebo group, respectively). Patients with SHT had significantly more atrial fibrillation, diabetes mellitus, no heparin use, streptokinase treatment, and early CT signs. In the multivariate analysis, HT was predicted by early CT signs and streptokinase treatment. SHT was predicted by diabetes mellitus, early CT signs, streptokinase treatment, and the interaction between streptokinase treatment and decreased level of consciousness. Among the streptokinase-treated patients, the same predictors remained. CONCLUSIONS: The relative risks of HT after streptokinase were in the same range in MAST-E as in other streptokinase and tPA trials. Early CT signs were strong predictors of both HT and SHT, stressing that these patients are at high risk of bleeding. In our study, the predictors of HT and SHT were similar to those of tPA trials in acute stroke.

Acute Disease↗
PubMed1999

[Prognostic importance of ambulatory arterial pressure monitoring in France. Initial results of the OCTAVE II study. OCTAVE II Research Group].

RATIONALE: Ambulatory blood pressure measurement (ABPM) is commonly used in clinical practice, whereas its added value to the management of hypertension is not definitely documented. OBJECTIVE: The OCTAVE II study was launched in 1991 to explore the prognostic value of ABPM, compared to that of the gold standard, the clinical blood pressure measurement. METHODS: Two hundred and six French cardiologists recruited 3569 participants over 18 years of age, provided they deemed ABPM was useful (mean age of 56 years, 52% of men, 65% already treated by antihypertensive drugs). The prognostic value of various blood pressure measurements, systolic or diastolic, clinical or ambulatory (diurnal, nocturnal or during 24 hours), has been assessed in multivariate models adjusted on the baseline characteristics associated with risk. The outcome was the occurrence of a major cardiovascular event, including stroke, myocardial infarction and cardiovascular death. RESULTS: After an average follow-up of five years, cardiovascular morbidity was known for 85% of the participants, and their vital status for 91%. On the whole population, the best prognostic indicators were systolic blood pressure compared with diastolic, ABPM compared with clinical blood pressure measurements, and nocturnal ABPM compared with diurnal ABPM. In the untreated participants at baseline, cardiovascular risk regularly increased among the four groups: normotensives, white-coat hypertensives, dippers, non-dippers. Between the extreme categories, the cardiovascular event rate was multiplied by 6.5. CONCLUSION: In this French population, ABPM and most of all its nocturnal component, was better correlated with cardiovascular prognosis. It remains to assess: 1) the general value of our findings, 2) the respective values of self blood pressure measurement versus ABPM, and 3) whether ABPM allows a better risk prevention.

Adult↗