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Biomedical subjects

C Jeandel

Publications and source records attributed to C Jeandel.

At least 37 records · Page 2Linked to original sources
PubMed2001

Differential influence of physical activity on lumbar spine and femoral neck bone mineral density in the elderly population.

This study investigates the relationship between lifetime physical activity and bone mineral density (BMD) at various sites in 129 healthy men and women aged 72.1 +/- 6.5 years. BMD was measured by dual energy x-ray absorptiometry, and physical activity was assessed by using the QUANTAP system (Quantification de l'Activité Physique), a standardized and structured computer-assisted interview tool designed to assess lifetime physical activity. Linear regression models controlling for age, gender, height, body mass, lean mass, and smoking habits were performed. Higher levels of sporting activity during youth were associated with greater lumbar spine BMD ( p < .001). Similarly, femoral neck BMD was greatest in subjects who reported regularly taking part in sports over the previous 20 years ( p <. 05) and during their whole lifetime ( p < 0.05). Sporting activity at the time of bone mass development increases subsequent lumbar spine BMD, and more recent sporting activity contributes to the preservation of femoral neck BMD. These results suggest that physical activity has a differential influence on BMD at different sites and at different ages, possibly related to the processes of bone construction and bone aging taking place at the time.

Aged↗
PubMed2000

[The preventive effects of physical activity in the elderly].

PHYSICAL ACTIVITY AND AGING: Physical activity prevents some age-related impairment. Physical activity reduces the decline of physical capacity which remains limited by maximal heart rate, and reduces the incidence of cardiovascular diseases by decreasing and preventing associated risk factors. Physical activity reduces age-related bone loss, its effect being potentialized by hormonal replacement therapy, and improves balance function, leading to a lower incidence of falls and fractures in older subjects. Physical activity helps to preserve nutritional balance and lean mass/fat mass ratio and reduces age-related insulin resistance. Moreover, physical activity has a beneficial influence on psychological function by improving cognitive performances and decreasing incidence of depression. Lastly, physical activity seems to reduce the incidence of several cancers, colic and mammary cancers particularly. PHYSICAL ACTIVITY, QUANTITY AND QUALITY OF LIFE: These multiple actions explain that physical activity, if it's adapted to subject's specificities increases longevity, delay entry in dependence and improves quality of life in older subjects. WHAT ARE THE RECOMMENDED ACTIVITIES: There is a superiority of individualized programs giving greater place to warm-up and associated endurance and resistive exercises intended to improve simultaneously cardiovascular and muscular functions. SPECIAL INTERESTS OF PHYSICAL ACTIVITY IN FRAIL AND VERY OLD SUBJECTS: Throughout its beneficial effects on aerobic capacity, muscular function, social integration, cognitive function and autonomy, physical activity may have a particular interest in frail subjects, when programs are adapted to physical capacities of these subjects and associated with nutritional supplements.

Accidental Falls↗
PubMed2000

[The role of drugs in falls in the elderly. Epidemiologic aspects].

FALLS AND POST-FALL SYNDROME: Falls are a major health problem among the elderly because of the resulting psychological sequelae (sometimes termed "post-fall syndrome") and in a few cases serious injury, particularly hip fractures. DRUGS AND FALLS: The scientific literature on the link between medications and falls and fractures suggests that psychotropic drugs used in about 50% of residents of nursing homes and in 20% in the community cause around 30% of falls in nursing homes and 20% of falls in the community. PSYCHOTROPS: The relative effect of selective serotonin reuptake inhibitors and tricyclic antidepressors and the relative effect of short/long acting or sedative/hypnotic benzodiazepines are not well established. CARDIOVASCULAR DRUGS: Appropriate use of cardiovascular medications and analgesics does not increase the risk of falls. PREVENTION: These data reinforce the concept that reducing the use of psychotrops, especially benzodiazepines, is probably one of the most effective means of reducing serious falls in older people.

Accidental Falls↗
PubMed2000

[Non-steroidal anti-inflammatory drugs with selectivity for cyclooxygenase-2 in Alzheimer's disease. Rationale and perspectives].

POSSIBLE INFLAMMATORY MECHANISMS: Alzheimer's disease (AD) is a degenerative disease of the brain including possibly inflammatory mechanisms, as illustrated by the presence of activated microglial cells in the periphery of senile plaques and neurofibrillary tangles and the subsequent release of proinflammatory mediators with neurotoxic potency. RATIONALE FOR NSAID USE: Although not firmly demonstrated, the rationale for the prescription of non steroidal anti-inflammatory drugs (NSAIDS) as neuroprotective agents in AD lies on epidemiological data having shown a reduced risk of developing AD in patients on long-term therapy with NSAIDs (non selective cyclo-oxygenase [COX] inhibitors). RATIONALE FOR THE USE OF SELECTIVE COX-2 INHIBITORS: The rationale for the prescription of selective COX-2 inhibitors as neuroprotective drugs in AD lies on: Epidemiological data having shown a reduced risk of developing AD in patients treated with anti-inflammatory doses of classical NSAIDs (inhibition of COX-1 and COX-2) but not with antithrombotic doses of aspirin (selective inhibition of COX-1), Cellular experiments, Demonstration of a better gastro-intestinal (GI) safety profile with selective COX-2 inhibitors than with classical NSAIDs in short-term studies, allowing a possible long-term use in AD. BEFORE PRESCRIBING: COX-2 may have an ambivalent functionality in the brain since the basal production of prostaglandins through COX-2 may participate in neuronal homeostasis whereas the expression of COX-2 is associated with brain development. Classical NSAIDs are ineffective in reducing the formation of senile plaque and neurofibrillary tangles in AD, which is consistent with an ability to reduce inflammation associated with activation of microglia but illustrates their failure to suppress the degenerative process. Prophylactic use of selective COX-2 NSAIDs can be considered on the basis of their good GI safety after 6 months of marketing in United States but need to be confirmed for a longer time. CURRENT TRIALS: Clinical studies focusing on both the prevention and the slowing down of early AD are under way with two recently launched selective COX-2 inhibitors, celecoxib and rofecoxib.

Adult↗
PubMed2000

Homocysteine, vitamins B6, B12, folate, and risk of coronary artery disease in patients undergoing diagnostic coronary angiography.

Homocysteine and vitamins B were correlated with coronary artery disease in patients undergoing diagnostic coronary angiography. 160 patients having > or =1 stenosis (G1), 55 patients having normal coronary arteries (G2) and 171 healthy volunteers (G3) were prospectively recruited. Homocysteine levels were significantly higher in patients, particularly in those with normal coronary angiograms, than in healthy subjects (13.8 +/-6.3 micromol/L in G1 (p < 0.0001) and 15.2 +/- 8.8 micromol/L in G2 (p < 0.0001) versus 10.1 +/- 3.1 micromol/L in G3). Homocysteine levels were not related to the extent of coronary artery disease. In patients with normal angiogram, vitamin B12 and folate levels were significantly higher compared with the other groups (p < 0.05 and p < 0.001, respectively) showing that vitamin B deficiency was not involved in the hyperhomocysteinemia. In conclusion, homocysteine and vitamins B levels do not contribute to discriminate for the presence of coronary artery disease in patients undergoing diagnostic coronary angiography. Homocysteine levels, however, were higher in patients referred for coronary angiography than in healthy controls.

Aged↗
PubMed2000

[Non-steroidal anti-inflammatory agents with selective inhibitory activity on cyclooxygenase-2. Interest and future prospects].

INTRODUCTION: Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the production of primary prostanoids by blocking the access of arachidonic acid to the active site of the cyclooxygenases (COXs). Because the prostanoids produced by COX-1 appear to play a physiological role (protection of the gastric mucosa, platelet aggregation, vascular homeostasis, maintenance of renal sodium-water balance) while those produced by COX-2 seem mainly to intervene in the inflammatory response and in certain processes associated with cell proliferation, the hypothesis has been put forward that the NSAIDs that are selective COX-2 inhibitors should theoretically be capable of maintaining NSAID therapeutic properties but also have fewer adverse side effects due to the maintenance of prostaglandin production at normal physiological levels. CURRENT KNOWLEDGE AND KEY POINTS: The hypothesis of COX isoenzyme selectivity has led to a proposed classification for COX inhibitors: 1) COX-1 selective inhibitors (low-dosage aspirin); 2) COX non-selective inhibitors (the majority of classified NSAIDs, which when administered over the long term, e.g., in cases of rheumatoid arthritis, cause duodenal ulcers in 20% of cases and gastric hemorrhage in 1-4% of cases/year); 3) COX-2 preferential inhibitors (meloxicam and nimesulide, which have fewer gastric side effects than standard NSAIDs, but which are not risk-free at high doses); 4) COX-2 selective inhibitors (celecoxib and rofecoxib). Preliminary clinical studies have shown that COX-2 selective inhibitors are as efficient as standard NSAIDs and have fewer adverse digestive side effects, thereby confirming the interest of this proposed classification. In the UK, the aforementioned studies have led to the commercialization of rofecoxib for the treatment of pain and osteoarthritis, while celecoxib has been introduced in medical practice in the USA and other countries for the treatment of rheumatoid arthritis and osteoarthritis. FUTURE PROSPECTS AND PROJECTS: Various epidemiological and laboratory studies have indicated that NSAIDs may be able to reduce the risk of cancer (colorectal cancer in particular) and Alzheimer's disease due to their inhibitory activity on COXs, especially COX-2. The therapeutic contribution of COX-2 specific inhibitors has to be more fully evaluated, particularly as these agents could delay the healing of duodenal ulcers and interfere with several COX-2-induced physiological functions. It is therefore suggested that until further information becomes available, this new class of NSAIDs should be used with caution in certain patient populations.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

A computer-assisted assessment of lifetime physical activity: reliability and validity of the QUANTAP software.

BACKGROUND: This study investigated the reliability and the validity of the QUANTAP (QUANTification de l'Activité Physique) interview-administered survey, a new computer-assisted tool designed to determine physical activity over a lifetime. METHODS: The tool was used to assess lifetime exercise habits in four dimensions (sport at school, leisure sport, occupation, daily activities) in 419 men and women aged 13-90 years. Physical activity indicators (time spent and energy expenditure) were calculated for 20-year periods. The inter-observer and intra-observer reliability of the tool was studied in two subgroups of 30 subjects. RESULTS: Intraclass correlation coefficients for intra-observer and inter-observer reliability varied from 0.56 to 0.96 and from 0.42 to 0.99 respectively according to the dimensions and indicators considered. Energy expenditure was not statistically significantly different from recommended nutritional intake in either males or females. Percent body fat at the time of the survey correlated with leisure sport (particularly in recent periods of practice): age-adjusted correlation coefficients varied from - 0.23 to - 0.45 among males, and from - 0.19 to - 0.31 among females. CONCLUSION: The results indicate that QUANTAP is reliable and valid to assess lifetime physical activity. It therefore provides a tool with which the long-term effects of physical activity on current health may be studied.

Activities of Daily Living↗
PubMed1999

Beneficial effect of proprioceptive physical activities on balance control in elderly human subjects.

Age and lack of physical activities may both be responsible for poor balance control. Conversely, physical activities may modulate postural control in elderly individuals. We examined which type of exercise might prove most beneficial to retain or regain proper balance. Nineteen healthy subjects, aged over 60, regularly practicing proprioceptive (group I) or bioenergetic (group II) physical activities and 21 controls only walking on a regular basis, were studied. All were submitted to a dynamic posturographic test and to a test evaluating lower limbs muscular strength. Control individuals displayed the poorest balance and muscular performance. Group I subjects had the best postural control with average muscular strength. In group II, muscular strength was significantly increased, but balance control was of poor quality. Proprioceptive exercise therefore appears to have the best impact on balance control.

Aged↗
PubMed1999

Differential effects of aging on heart rate variability and blood pressure variability.

Previous studies investigating autonomic cardiovascular control in elderly persons usually included analysis of R-R interval but not of blood pressure variability. "Physiological" blood pressure rise during the aging process was not accounted for as a possible confounding factor. This study was designed to characterize the relationship between age and short-term heart rate (HR) and blood pressure (BP) variability, independently of the "physiological" rise in BP associated to aging. The study was carried out in 65 "normotensive" (BP< or =140/80 mm Hg) healthy subjects, ranging in age from 18 to 80 years. BP and HR were recorded at rest with a Finapres device. Low-frequency (LF = 0.066 to 0.129 Hz) and high-frequency (HF = respiratory peak +/-0.05 Hz) components of HR and BP variability were assessed using fast-Fourier spectral analysis. Transfer-function analysis between systolic BP and HR variability permitted the calculation of the gain of baroreflex sensitivity. Significant results of this study include a continuous and linear decline with age of normalized LF spectral power of HR in the standing position and of normalized HF spectral power of HR during paced breathing. No correlation was found between age and BP variability, except for LF diastolic BP spectral power in the standing position. The baroreflex gain was negatively correlated with age. The effect of aging on autonomic nervous system cardiac control is progressive and continuous throughout an 18-80 years age range. Although the aging process diminished HR variability and diastolic BP variability, it had no influence on systolic BP variability.

Adolescent↗
PubMed1999

Effects of physical and sporting activities on balance control in elderly people.

OBJECTIVE: Balance disorders increase with aging and raise the risk of accidental falls in the elderly. It has been suggested that the practice of physical and sporting activities (PSA) efficiently counteracts these age related disorders, reducing the risk of falling significantly. METHODS: This study, principally based on a period during which the subjects were engaged in PSA, included 65 healthy subjects, aged over 60, who were living at home. Three series of posturographic tests (static, dynamic with a single and fast upward tilt, and dynamic with slow sinusoidal oscillations) analysing the centre of foot pressure displacements or electromyographic responses were conducted to determine the effects of PSA practice on balance control. RESULTS: The major variables of postural control were best in subjects who had always practised PSA (AA group). Those who did not take part in PSA at all (II group) had the worst postural performances, whatever the test. Subjects having lately begun PSA practice (IA group) had good postural performances, close to those of the AA group, whereas the subjects who had stopped the practice of PSA at an early age (AI group) did not perform as well. Overall, the postural control in the group studied decreased in the order AA > IA > AI > II. CONCLUSIONS: The period during which PSA are practised seems to be of major importance, having a positive bearing on postural control. It seems that recent periods of practice have greater beneficial effects on the subject's postural stability than PSA practice only at an early age. These data are compatible with the fact that PSA are extremely useful for elderly people even if it has not been a lifelong habit.

Accidental Falls↗
PubMed1998

[Alzheimer disease. Epidemiology, genetics and physiopathological hypotheses].

RISK FACTORS: Aging is the chief risk factor for Alzheimer's disease (AD). Other risk factors are aluminum in drinking water, diabetes mellitus, head trauma. Protective factors are: higher education, cigarette smoking, nonsteroidal anti-inflammatory drugs and estrogen use. GENETIC FACTORS: Mutations of presenilins 1 and 2 and of the APP gene in families with early-onset AD. Apolipoprotein E polymorphism in late-onset familial and sporadic AD. PATHOGENIC HYPOTHESES: Amyloid deposits in senile plaques and therefore dementia could be due to an overproduction of Abeta (Down's syndrome) or due to the primary (APP mutation) or secondary (role of diabetes, mellitus, apoE polymorphism: protective effect of estrogen) abnormal neurotoxic feature of Abeta. The hyperphosphorylation of tau (a protein which plays a pivotal role in the axonal transport), perhaps regulated by the apoE polymorphism could lead to neurofibrillar degeneration. Neurotoxic mediators produced by the activated microglia (perhaps activated by neuronal damage) and oxidative stress could also be involved in the neurodegeneration.

Age Factors↗