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Biomedical subjects

C Ribot

Publications and source records attributed to C Ribot.

At least 73 records · Page 4Linked to original sources
PubMed1993

The effects of menopause on longitudinal bone loss from the spine.

Two hundred and thirty women aged 45-66 years were divided into three groups according to their menopausal status and were followed to assess the changes in vertebral bone mineral density (BMD). These included 71 premenopausal, 42 perimenopausal, and 117 postmenopausal women. Menopausal status was assessed through menstrual history and plasma concentrations of 17 beta estradiol and luteinizing hormone. BMD was measured by dual photon absorptiometry between 2 and 5 times over an average period of 27 months, and annual rates of changes were calculated by linear regression. BMD decreased significantly (P < 0.0001) in the three groups during the follow-up. Mean (+/- SD) annual rate of change was -0.79 +/- 1.5% for premenopausal, -2.35 +/- 1.5% for perimenopausal, and -1.24 +/- 1.5% for postmenopausal women. There was no difference in the rates of bone loss between the perimenopausal group and the postmenopausal group within 3 years after menopause (1-2 years: -2.34 +/- 2.1%; 2-3 years: -1.9 +/- 1.5%). Thereafter, rates decreased exponentially with time since menopause to fall out at the same level as the premenopausal level. These longitudinal data indicate that vertebral bone loss begins before menopause and accelerates sharply during menopause to decline exponentially with time after 3 years.

Absorptiometry, Photon↗
PubMed1993

Spine and femur densitometry at the menopause: are both sites necessary in the assessment of the risk of osteoporosis?

The aim of our study was to compare the results provided by the measurement of vertebral and femoral bone mineral density (BMD) for assessing the individual risk of osteoporosis as defined by either low BMD and/or rapid bone loss. Vertebral and femoral BMD were measured twice at a mean interval of 21 months in 85 normal, early postmenopausal women who had passed a natural menopause 6 months to 3 years previously. According to the measurement site, 36% (spine), 29% (femoral neck), 35% (Ward's triangle), and 25% (trochanter) fall in the "at risk" category, defined by a BMD value of 1 SD or more below the normal values for premenopausal women. Based on vertebral BMD, 39-48% of the women at risk had a normal femoral BMD. On the other hand, 24-37% of the women classified at risk based on femoral BMD maintained a low risk at the vertebral level. The annual rate of bone loss was significantly greater for the Ward's triangle (-2.7 +/- 3.8%) and femoral neck (-2.1 +/- 2.5%) than for the spine (-1.5 +/- 2.1%) and trochanter (-1.5 +/- 3.4%). There was a significant relationship between the rate of loss measured at the spine and femoral levels (r = 0.34-0.58). Among the 21 women with a rapid vertebral bone loss, 48-67% had a low bone loss at the femoral level and vice versa. The ratio between mean rate of loss and the precision of the measurement sites was greater for the spine (1.6) compared with the femur (1.1-0.71).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1993

Risk factors for hip fracture. MEDOS study: results of the Toulouse Centre.

The development of preventive strategies for hip fractures requires better identification of risk factors. The MEDOS study was designed to study prospectively the incidence of hip fracture in 14 centres from six countries and characterise risk factors. At one centre (Toulouse), data were gathered from questionnaires completed by 386 cases of hip fracture aged over 50 years and 848 age- and sex-matched controls over a 12-month period. Of the 935 variables of the MEDOS questionnaire, 235, grouped into 56 items, were statistically analysed. Odds ratios (and 95% confidence intervals) were estimated for each variable from a multiple stepwise logistic regression model. The population comprised 19.2% men and 80.8% women, with a mean age of 80 +/- 8.8 years; 80% were living in an urban area and 76% with their family. Of the 17 significant variables, moderate excess weight and a high nutritional intake of calcium were associated with a decreased risk of hip fracture. Loss of autonomy, a higher height than normal (> 1SD), and a history of previous fractures significantly increased the risk of fracture. Interestingly, all these variables accounted for only 18% of the risk of hip fracture.

Aged↗
PubMed1993

Effect of long-term administration of progestogen on post-menopausal bone loss: result of a two-year, controlled randomized study.

OBJECTIVE: We determined whether a progestogen given alone to post-menopausal women may prevent bone loss. STUDY DESIGN: Thirty-five early post-menopausal women who had not received any form of treatment to prevent bone loss were randomly assigned to a 2-year regimen of 500 micrograms/day of a gestagen derived from 19-norprogesterone (Promegestone) or a placebo for 21 days out of a 28-day treatment cycle. Bone mineral density of the spine was measured by dual photon absorptiometry. RESULTS: After 2 years of treatment bone mineral density decreased significantly in the placebo group by a mean of 4.5%. In the gestagen group, the rate of bone change was significantly lower as compared to the placebo group (-1.3% +/- 1.2% vs -4.5% +/- 2% (mean +/- SEM), P < 0.05). There were no changes in the biochemical bone turnover parameters in the placebo group but in the gestagen group a significant decrease was observed in the urinary calcium excretion after 2 years. CONCLUSION: The results suggest that a gestagen with no androgenic action can partly counteract early post-menopausal bone loss.

Administration, Oral↗
PubMed1993

Vertebral postmenopausal bone loss is reduced in overweight women: a longitudinal study in 155 early postmenopausal women.

To study the influence of excess body weight on vertebral postmenopausal bone loss, 155 healthy early postmenopausal women were divided into 2 groups according to their body mass index (BMI = weight/height2) and prospectively followed over a mean 31-month period. Spinal (L2-L4) bone mineral density was measured by dual photon absorptiometry. The annual rate of vertebral bone loss (percentage) was significantly reduced (-0.54 +/- 1.1% vs. -1.46 +/- 1.6%; P < 0.05) in the overweight group (BMI, > or = 25; n = 40) compared to that in the normal weight group (BMI, < 25; n = 115). At baseline, a significant decrease in the urinary calcium/creatinine ratio was observed in the overweight group, which suggested a decrease in bone turnover. A significant correlation was found between the annual rate of bone loss and the BMI (r = 0.21; P < 0.05), but not the body weight. The positive correlation between vertebral postmenopausal rate of bone loss and BMI was confirmed after adjustment for age and time since menopause. Moreover, plasma dehydroepiandrosterone sulfate levels were higher in the high BMI group than in the normal BMI group (P < 0.05). We conclude that within the first years after menopause, moderate excess body weight significantly reduces vertebral postmenopausal bone loss. This effect is probably related to excess adipose tissue through increased conversion of estrogen from adrenal precursors and/or increased production of adrenal androgens.

Body Mass Index↗
PubMed1993

[Alexander's disease in adults and diffuse cerebral gliomatosis in 2 members of the same family].

A 31-year old woman died after 10 years of progressive dysautonomia and cerebellar and pyramidal symptoms. CT scan showed pontine, bulbar and cerebellar atrophy. Post-mortem examination revealed Rosenthal's fibers widespread throughout the CNS, but especially in the subependymal and perivascular regions. White matter cavitations involving peri-ventricular regions, hilum of dentate nuclei and pons were observed, leading to a diagnosis of adult form of Alexander's disease. At the age of 5, the patient had been operated upon for a chiasmatic tumor. Microscopic examination revealed a pilocytic astrocytoma without Rosenthal's fibers. No complementary radiotherapy had been done. Her mother has been operated upon in 1972, for a high-grade glioma and is still alive 20 years later. This suggests diffuse cerebral gliomatosis. This family history may suggest a relation between these different diseases. They might be the result of a transmissible astrocytic abnormality with varying expression.

Adult↗
PubMed1993

[Postmenopausal bone loss: results of a topographic study by X-ray absorptiometry].

Bone density was determined in six areas (head, arms, thorax, spine, legs, and pelvis) using total body dual photon X-ray absorptiometry. Values were compared with the conventional anterior-posterior lumbar spine (L2-L4) absorptiometry measurement in 20 young females (25 +/- 4.2 years), 41 perimenopausal females (51 +/- 2 years), and 39 postmenopausal females (time since menopause 2.7 +/- 1.9 years). The two older groups were of similar age and physical characteristics. Total body bone mineral density and leg bone mineral density were significantly lower in the perimenopausal women than in the younger women, but this difference was no longer apparent after adjustment for height. Postmenopausal women exhibited diffuse bone loss with a particularly marked decrease in the lumbar spine measurement. Lumbar bone mineral density was significantly correlated with bone mineral densities at other sites; correlation coefficients ranged from r = 0.56 for the head to r = 0.83 for the total skeleton. However, one third of females with a lumbar measurement predictive of a high fracture risk had normal bone mineral density at another site, and vice versa. Our findings show that postmenopausal bone loss affects the entire skeleton and that measurements should be performed at several sites in order to identify high-risk women at cessation of menses.

Absorptiometry, Photon↗
PubMed1993

[Postmenopausal osteoporosis: clinical characteristics in patients first vertebral crush fracture. Results of the GRIO National Multicenter Survey. Groupe de Recherche et d'Information sur les Osteoporoses].

This national multicenter study by the French Task Force on Osteoporosis Research and Information (Groupe de Recherche et d'Information sur l'Ostéoporose GRIO) was carried out to define clinical features in women presenting with a first osteoporosis-related vertebral crush fracture. Seventy-four patients with a less than three-month history of back pain due to a first vertebral fracture documented on the basis of stringent roentgenographic criteria, were compared to 74 normal age-matched female controls. Mean age at first vertebral fracture was 67 +/- 7 years. Cases and controls filled out a 78-item questionnaire on morphology, reproductive function, environmental factors, and previous fractures. The circumstances of onset and site of the vertebral fracture were recorded. Both groups were comparable in terms of age, body weight, hair color and eye color, whereas mean height was smaller by 2 cm in cases (p < 0.02). Among data on reproductive function, the only difference was a younger age at last menses among cases (47.7 +/- 5.7 versus 49.8 +/- 4.8 years); number of pregnancies and duration of breast-feeding were comparable in cases and controls. Environmental factors (smoking, alcohol use, physical activity, dietary calcium) were similar in the two groups. Cases were more likely than controls to report a history of appendicular fractures and/or a positive family history for vertebral osteoporosis. This study in French women suggests that the first osteoporotic vertebral fracture occurs approximately 20 years after cessation of menses and that risk factors include earlier age at last menses, a history of fracture, and a family history of vertebral osteoporosis.

Age Distribution↗
PubMed1993

[Surgical applications of anatomical variations of the median nerve at the wrist].

After a brief report of median nerve anatomy at wrist, authors describe terminal variations of its distribution. Classic description of five terminal sensitive and motor median nerve branches is not constant. Many anatomic variations have been reported and so many, classifications proposed. Lantz' classification is useful, it may be divided in four groups. Other anatomic variations concern cutaneous palmar nerve branch and different nervous anastomosis. Advantage of this anatomic study is incidence of variations on surgical access of carpal tunnel. Those nervous variations of median nerve at wrist are frequent, unknown and wrong indexed and may be so many "anatomic traps" for surgeon.

Anatomy, Regional↗
PubMed1993

[Is it possible to identify women with rapid vertebral bone loss during menopause? Result of a longitudinal study of 92 women at the onset of menopause].

Low bone mass is the main risk factors for osteoporosis. The role of the rate of bone loss following cessation of menses is more difficult to evaluate. We prospectively studied vertebral bone loss in 92 women six months to three years after cessation of menses in order to determine the clinical and biological characteristics of the subgroup of subjects with accelerated bone loss. Clinical characteristics, hormone assay results, and values of the main biochemical markers of bone turnover were recorded at the initial evaluation and correlations between these parameters and the rate of bone loss were investigated. Serial measurements of vertebral bone density were performed using dual photon absorptiometry. Mean duration of the observation period was 31 +/- 13 months. Mean rate of bone loss was -1.66% per year (range 1.6% to 7.7%). In women with accelerated vertebral bone loss i.e., a greater than 2.5% decrease in bone density per year (25th centile), there were trends towards lower values for body mass index and weight (non-significant) and a significantly higher urinary calcium/urinary creatinine ratio (p < 0.05) as compared with the rest of the study group. Rate of bone loss was weakly correlated (p < 0.05) with body mass index (r = 0.22) and with the urinary calcium/urinary creatinine ratio (r = 0.23) but demonstrated no correlations with osteocalcin levels or serum alkaline phosphatase activity. In conclusion, none of the clinical features or laboratory parameters studied proved capable of reliably predicting the rate of vertebral bone loss in individual women shortly after cessation of menses.

Absorptiometry, Photon↗
PubMed1992

[Postmenopausal bone loss. Role of progesterone and androgens].

Oestrogen deficiency is the main physiopathological factor of postmenopausal osteoporosis. The repercussions on bone metabolism of decrease in other sex steroid levels (progesterone, androgens) remains imperfectly known. Several studies on both animals and man have demonstrated that androgens and progestogens derived from testosterone have an anabolic effect on bone tissue. The latest data from studies conducted in non-menopausal women treated with progesterone suggest that this hormone might prevent bone loss. The mechanism of action of this effect on cells remain to be determined, even though progesterone has been shown to exert a mitogenic activity in vitro. Altogether, these data suggest that side by side with oestrogen deficiency the decrease of other sex steroid levels might also play a role in the physiopathology of postmenopausal bone loss.

Adult↗
PubMed1992

[Postmenopausal bone loss. Role of estrogens].

Menopause is attended by an increase in bone remodelling, predominantly resorption, resulting in a trabecular and cortical bone loss which can be prevented by administration of oestrogens. This indicates that oestrogen deficiency is one of the major physiopathological elements of postmenopausal osteoporosis. The mechanism of action of oestrogens has not yet been fully elucidated. The recent finding of functional oestrogen receptors in osteoblasts suggests that oestrogens might have a direct action on bone cells, side by side with their action on the activity or production of calcitropic hormones. The antiresorptive effect of oestrogens might be due to the osteoblasts producing one or several local factors that modulate the differentiation and/or recruitment of osteoclasts. Moreover, animal studies have provided arguments in favour of a direct action of oestrogens on bone formation.

Aged↗
PubMed1992

[Vertebral, femoral and radial bone density in simulation of prolonged weightlessness. Experience with healthy volunteers].

Disturbances in bone tissue induced by weightlessness in man are incompletely known. All we possess are indirect data which show negativation of the calcium-phosphate balance and bone density measurements mainly in peripheral bones (calcaneum and radius bones). Staying in supine position with the head down (the so-called anti-orthostatic position) is a means of simulating on earth the effects of weightlessness in space flights. We studied the changes in vertebral, femoral and radial bone densities that might occur in 7 healthy volunteers subjected to two 1-month period of bed rest with strict (-6 degrees) anti-orthostatic position. No significant variation was recorded at the end of each period. When the two periods were added the mean vertebral bone loss was -0.9 percent per month. This figure was comparable to that found in similar studies performed in the USA with longer periods of bed rest. The bone loss in such experiments was 4 to 8 times less than that reported for pathological immobilization. Further simulation studies are needed to evaluate the bone loss kinetics and to test the effectiveness of the preventive measures used in spatial flights.

Adult↗
PubMed1992

Prevention of post-menopausal bone loss with 1 alpha-hydroxy vitamin D3. A three-year prospective study.

An open and controlled prospective study was used to assess the preventive efficiency of 1 alpha-hydroxy vitamin D3 (1 alpha (OH) Vit. D3) on post-menopausal vertebral bone loss. Of the 36 patients included in the study, 25 completed two years of treatment with 1 microgram/day of 1 alpha (OH) Vit. D3 and 500 mg of calcium. The vertebral bone mineral density measured by dual photon absorptiometry did not vary in the treated group, whereas it decreased significantly in the control group at the end of the 2 years. At two years, withdrawal of treatment led to a significant bone loss, whereas bone mass remained stable in a subgroup of patients who underwent a third year of treatment with 1 alpha (OH) Vit. D3. Overall, tolerance was satisfactory. However, urinary calcium increased significantly during treatment and one third of the patients developed hypercalciuria > or = 7.5 mmoles/24 h. No variation in either serum calcium or creatinine levels was noted. These results indicate that 1 alpha (OH) Vit. D3 could be useful in preventing post-menopausal bone loss provided it was complemented by regular monitoring of urinary calcium excretion.

Aged↗
PubMed1992

Effect of 17 beta-oestradiol and norethisterone acetate on vertebral bone mass and lipid metabolism in early postmenopausal women.

We studied the effects on vertebral bone density and lipid metabolism of long-term administration of 17 beta-oestradiol combined with norethisterone acetate in a 2-year prospective study carried out in 40 women, divided into 2 groups of 20 subjects. One group received treatment, while the other constituted the control group. In the untreated group, vertebral bone density was found to be decreased significantly by 1.1% at 12 months and by 4.4% at 24 months in relation to initial values (P < 0.001). Total cholesterol was significantly higher (P < 0.05) at the end of the 2-year period. By contrast, in the treated group, bone density showed significant increases of 5.6% at 12 months and 7% at 24 months (P < 0.001). Significant reductions in the biochemical markers of bone remodelling (osteocalcin and the urinary calcium/urinary creatinine ratio) were also observed. Total cholesterol, high-density-lipoprotein cholesterol, low-density-lipoprotein cholesterol and triglycerides did not change significantly during treatment. These results, as well as the good compliance with treatment (78%), suggest that this treatment regimen could be useful in the prevention of postmenopausal bone loss.

Bone Density↗
PubMed1992

Assessment of the risk of post-menopausal osteoporosis using clinical factors.

OBJECTIVE: We wished to assess the predictive value of the main clinical risk factors for osteoporosis over a low vertebral bone mineral density. DESIGN: A cross-sectional study was made of a cohort of peri and post-menopausal women (mean age, 54 years). PATIENTS: One thousand, five hundred and sixty-five normal white women were selected from among the women referred to our menopause clinic for screening and prevention of osteoporosis. MEASUREMENTS: Each woman had replied to a detailed standardized questionnaire including the main clinical risk factors and had her bone density measured using dual photon absorptiometry. RESULTS: The predictive value for a low vertebral bone mineral density (2 SD below the normal young adult value) was assessed for 15 historical and anthropometric variables. Among these, age, age at menarche, weight, height, menopause and its duration, were independent predictors of a low bone mineral density, in a multiple logistic regression analysis. Odds ratios were calculated for each of these variables, weight, menopause and its duration being the three most influential variables. At best this model makes it possible to correctly classify 73% of women with a low bone mineral density and 66% of those with a normal bone mineral density. If this model is used for screening, it could possibly save 25% of bone densitometry examinations. CONCLUSIONS: Direct bone densitometry remains indispensable to assess osteoporosis risk, since risk factors alone are not sufficient for accurate delineation of either low or normal bone mineral density.

Adult↗
PubMed1992

[Fracture of the upper extremity of the femur in elderly women: respective role of fall and bone demineralization].

Fractures of the proximal femur in elderly individuals are becoming increasingly common in the industrialized world and represent a heavy burden in both socioeconomic and human terms. Two factors are key to the pathophysiology of these fractures: falls and decreased bone strength due to osteoporosis. Femoral and vertebral bone density was measured in 40 elderly women (83 +/- 5 years) who experienced a fall; in those who developed a femoral fracture as a result of the fall, femoral bone density was lower by 12 to 21% (z score: -0.7 to -1.04) than in those with no fracture, after adjustment for age, height and weight. Femoral neck and trochanteric area measurements had the best predictive value (area under the RoC curve: 75% +/- 8%). These was no difference by anatomic fracture type (neck or trochanter). Patients with pertrochanteric fractures had lower vertebral bone densities than controls. These findings, together with recent prospective data, demonstrate that in addition to falls, bone loss (osteoporosis) promotes the occurrence of fractures of the proximal femur in elderly patients. This has important practical implications for the detection and prevention of these fractures.

Accidental Falls↗