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Biomedical subjects

M A Mayoux-Benhamou

Publications and source records attributed to M A Mayoux-Benhamou.

At least 19 recordsLinked to original sources
PubMed2004

Predictors of compliance with a home-based exercise program added to usual medical care in preventing postmenopausal osteoporosis: an 18-month prospective study.

This prospective 18-month study was designed to assess long-term compliance with a program of exercise aimed to prevent osteoporosis after an educational intervention and to uncover determinants of compliance. A total of 135 postmenopausal women were recruited by flyers or instructed by their physicians to participate in an educational session added to usual medical care. After a baseline visit and dual-energy X-ray absorptiometry, volunteers participated in a 1-day educational session consisting of a lecture and discussion on guidelines for appropriate physical activity and training in a home-based exercise program taught by a physical therapist. Scheduled follow-up visits were 1, 6, and 18 months after the educational session. Compliance with the exercise program was defined as an exercise practice rate 50% or greater than the prescribed training. The 18-month compliance rate was 17.8% (24/135). The main reason for withdrawal from the program was lack of motivation. Two variables predicted compliance: contraindication for hormone replacement therapy (odds ratio [OR] = 0.13; 95% confidence interval [95% CI], 0.04 to 0.46) and general physical function scores from an SF-36 questionnaire (OR=1.26; 95% CI, 1.03 to 1.5). To a lesser extent, osteoporosis risk, defined as a femoral T-score < or =-2.5, predicted compliance (OR=0.34; 95% CI, 0.10 to 1.16). Despite the addition of an educational session to usual medical care to inform participants about the benefits of exercise, only a minority of postmenopausal women adhered to a home-based exercise program after 18 months.

Exercise Therapy↗
PubMed2001

Value of the bell test and the hyperextension test for diagnosis in sciatica associated with disc herniation: comparison with Lasègue's sign and the crossed Lasègue's sign.

OBJECTIVES: To evaluate the reliability, sensitivity, specificity and positive (PPV) and negative (NPV) predictive values for the diagnosis of sciatica associated with disc herniation of the bell test (BT) and the hyperextension test (HT). METHODS: According to magnetic resonance imaging, computed tomography scanning or myelography findings, patients were classified as having sciatica associated with disc herniation (group A) or sciatica without disc herniation or sciatica of other mechanical origin (group B). Four clinical manoeuvres [bell test (BT), hyperextension test (HT), Lasègue's sign (LS) and the crossed Lasègue's sign (CL)] were tested by three investigators. Intra- and interobserver reliabilities were calculated using the kappa correlation coefficient or the intraclass correlation coefficient (ICC). The sensitivity, specificity, PPV and NPV of the four manoeuvres were calculated. Stepwise logistic regression analysis was performed to determine the best set of variables predicting sciatica caused by disc herniation. RESULTS: Seventy-eight patients (43 in group A, 35 in group B; 33 males) with a mean age of 50+/-16 yr were included. Interobserver reliabilities ranged from 0.58 to 0.64 for the BT, 0.35 to 0.50 for the HT, 0.27 to 0.47 for LS and 0.43 to 0.72 for CL. LS had the best sensitivity (0.77-0.83) and CL the best specificity (0.74-0.89), while PPV and NPV were equivalent for the four manoeuvres (0.55-0.75 for PPV and 0.45-0.59 for NPV). The best PPV was observed for the association of HT with CL (0.67-0.85). Stepwise logistic regression analysis did not allow us to propose a set of variables predicting sciatica caused by disc herniation. CONCLUSION: This study suggests that clinical values of the BT and HT are of interest, and are similar to those of LS and CL.

Adolescent↗
PubMed2001

[Fetal development and postnatal maturation of the longus colli muscle].

In adults, the predominant expression of a slow phenotype in the m. longus colli corresponds to its important postural function. Morphologically, there is a dispersion in fiber size predominating on the fast type 2 fibers which are significantly smaller than the slow type 1 fibers. We deemed it of interest, therefore, to analyze the metabolic differentiation of the muscle longus colli during its development. This study has been carried out on six anatomical samples, in foetuses aged between 16 and 40 weeks of pregnancy and in an 18 month-old child. The histological study combined H&E staining and immunohistochemical techniques (using antibodies specific for the slow and the fast isoforms of the myosin heavy chains). Our results indicate that the m. longus colli differentiates during the foetal period in a way which is quite comparable to that of other skeletal muscles, such as the quadriceps. In this series, a major slow predominance with a significant dispersion in fiber size was first observed in the 18 month-old child. Thus, it can be concluded that the establishment of the adult phenotype of this muscle starts during postnatal life, following the development of the mechanisms holding up the head and neck and leading to the appearance of the cervical lordosis.

Gestational Age↗
PubMed2001

[Metabolic differentiation of the human longus colli muscle].

The cervical muscles have a dual postural and dynamic function, in order to ensure both the stability and the motility of the cervical spine. The functional duality together with the complexity of the cervico-cephalic system render the study of the cervical muscles difficult, and their physiology is not fully understood in humans. This study has been carried out on ten samples from the m. longus colli, taken during a surgical procedure in patients aged between 36 to 62 years. The histological study combined enzyme histochemical (ATPases) and immunohistochemical techniques (using antibodies specific for the slow and the fast isoforms of the myosin heavy chains). Our results indicate that, in all cases, the m. longus colli is composed of muscle fibers with peripheral nuclei and with a relative dispersion in size. Histochemically, the type 1 and type 2 fibers express exclusively either the slow or the fast myosin heavy chain. From a quantitative point of view, the proportion of the slow fibers varies between extreme values of 30 and 73%; in addition, the dispersion in fiber size predominates on the fast type 2 fibers which are smaller than the slow type 1 fibers. Thus, most of the muscles that we have studied have histologically a slow predominance. This predominant expression of a slow phenotype in the m. longus colli corresponds to its important postural function, in addition to its phasic role during the flexion of the cervical spine.

Adult↗
PubMed2000

[Which rehabilitation for which low back pain?].

Many rehabilitation technics for low back pain are available. Their aims are short time pain decrease, muscular strengthening in flexion or extension, increased hip and lumbar spine mobility, improved lumbar and pelvic proprioceptive sensibility, improved general fitness. During the past ten years, studies meeting widely accepted validity and applicability for therapeutic trials have addressed the clinical efficacy of rehabilitation in low back pain patients. Most studies assessing the back school approach have found no benefit. Spinal extension and flexion programs have yielded short-time improvements, without difference between the two methods. There is now strong evidence that functional restoration programs provide long-term benefits including better social and occupational outcomes.

Humans↗
PubMed1999

Cross-sectional study of weight-bearing activity on proximal femur bone mineral density.

In this cross-sectional study we investigated the effect of compressive and tensile forces applied on the proximal femur during weight-bearing activities. Ninety-seven men (29.9 +/- 1.7 years) were divided into two groups: 69 exercisers who had practiced regular high-impact weight-bearing activities for at least 5 years and 28 controls who had been sedentary for at least 5 years. The maximum isometric hip abduction strength was measured. The bone mineral density (BMD) of the femoral neck and the greater trochanter was assessed using dual-energy X-ray absorptiometry (DXA). Controls were considered as the reference population to calculate the Z score. Mean BMD values of the femoral neck were 0.97 g/cm2 on both sides in the exercisers and 0.83 g/cm2 on the right side and 0.84 g/cm2 on the left side in the controls. Mean BMD values of the greater trochanter were 0.86 g/cm2 on the right side and 0.87 g/cm2 on the left side in the exercisers, 0.73 g/cm2 on the right side and 0.72 g/cm2 on the left side in the controls. The BMD was significantly higher in exercisers at both trochanteric and cervical sites (P = 0. 0001). Both left and right hip abduction strength was significantly greater in the exercisers than in the controls (P < 0.05) and was positively correlated to cervical and trochanteric BMD (P < 0.01). In the exerciser group, the trochanteric Z score was higher than the cervical Z score at both right (P = 0.06) and left (P = 0.002) sides. Therefore, the proximal femoral BMD was significantly greater in exercised subjects as compared with sedentary controls. The difference was observed at the level of both the femoral neck (where it is known anatomically that only compressive gravitational forces are exerted) and the greater trochanter (where it is known that tensile forces are exerted). This result suggests the participation of both compressive and tensile forces in the mechanisms by which exercise influences bone trophicity.

Adult↗
PubMed1999

[Growth of spinal muscles in the human fetus].

The spinal muscles, located in the paravertebral region, derive embryologically from the medial part of the somites. It has been shown in different animals that their differentiation occurs within the somite itself following the action of diffusible factors of chordal, neural and epiblastic origin. In these animal species, it thus appears that several factors determine the potential of migration as well as the muscular specification of the somitic cells. In 13 human foetuses, aged from 12 to 40 weeks of pregnancy, without any neuro-muscular disorder, transversal sections of both the vertebral and the paravertebral regions have been made at the level of the thorax and of the abdomen. Following rapid fixation, decalcification and paraffin embedding, semi-serial histological sections of 10 microns have been stained with H&E or Masson's trichrome and examined under light microscopy. Our results confirm that the primordia of the spinal muscles are present before the end of the embryonic period proper. The main modifications observed during foetal life concern the overall growth of the muscular mass, with a neat preeminence of the lombar region after 18 weeks. The differentiation of the individual muscle fibers is similar to that observed in other territories in the developing organism, with a craniocaudal gradient of maturation. Thus, if myogenic specificities really exist in the medial part of the somites in humans, it is likely that they concern the initial mechanisms involved in the activation of the myogenic program and not the mechanisms leading to the subsequent differentiation and growth of the fibres.

Cell Differentiation↗
PubMed1998

Plantar flexion force is related to calcaneus bone ultrasonic parameters in postmenopausal women.

The aim of this report was to study the relationship between the plantar flexion strength produced by contraction of the triceps surae (gastrocnemii-soleus) muscle and the calcaneus bone parameters assessed by quantitative ultrasound in 45 healthy postmenopausal women. Plantar flexion strength was related to calcaneus broadband ultrasound attenuation (BUA) (r = 0.43, P = 0.003) and to speed of sound (SOS) (r = 0.3, P = 0.04). Plantar flexion appeared to predict ultrasonic properties, independently of body weight (R2 = 19% and 9% for BUA and SOS, respectively). These results suggest that the stresses related to locomotion locally enhance bone remodeling but further studies are needed to identify the respective role of the compressive strains related to ground reaction forces at heel-strike and the muscular tensile strains applied on the calcaneus where the calcaneal tendon is inserted.

Calcaneus↗
PubMed1997

Selective electromyography of dorsal neck muscles in humans.

The patterns of activation of splenius capitis, semispinalis capitis, transversospinalis, and levator scapulae muscles were studied during various head-neck positions, movements, and isometric tests in 19 healthy human subjects. Myoelectric activities were recorded with intramuscular bipolar wire electrodes. Cervical computerized tomography of each subject was performed before the electromyography session in order to guide electrode insertion. Head motion was recorded using an electromechanical device. This report demonstrates that head motion results from a complex interaction of active muscular forces, passive ligamentous forces, and gravity. Splenius capitis has two main functions, i.e., cervical extension and ipsilateral rotation. Semi spinalis capitis and the transversospinalis are mainly extensors, and levator scapulae acts primarily on the shoulder girdle. Splenius capitis, semispinalis capitis, and transversospinalis play a subordinate part in ipsilateral tilting. In addition, most subjects' semispinalis capitis were gradually recruited during ipsilateral rotation. No signal was detected from the transversospinalis during rotation tests.

Adult↗
PubMed1997

Effect of psoas training on postmenopausal lumbar bone loss: a 3-year follow-up study.

The present study completed a previous randomized trial that demonstrated the protective effect of 1-year psoas training on lumbar bone loss in postmenopausal women. Computerized tomography had been carried out at the beginning (CT1) and at the end (CT2) of this trial. In the present study, 67 women having completed the first trial were asked to practice psoas exercises (60 hip flexions in sitting position with a 5 kg weight on the knee) for 2 additional years with a third CT control at the end of this period (CT3). The aim of this complementary study was to assess the compliance rate and long-term effect on bone of daily psoas muscle training over a longer period. Twenty-one women performed this daily psoas training for 3 years from CT1 to CT3, and 14 acted as controls during the same period. Fourteen women were controls during the first year (from CT1 to CT2) but practiced psoas training during the following 2 years (from CT2 to CT3). Four women were psoas trained during the first year (from CT1 to CT2) and subsequently crossed over to the control group for the last 2 years. The compliance rate was 42%, with an attendance rate of 88%. The lumbar bone loss was lower in the 21 women trained over the 3 years (-3.26 +/- 28.45 mg/cm3) than in the 14 untrained women (-16.79 +/- 8.51 mg/cm3) (P = 0.02). The bone loss was not significantly reduced between the two periods of the study in the 12 women having been controls from CT1 to CT2 and having crossed over to the active training group from CT2 to CT3. Psoas training may be effective against lumbar bone loss. We conclude that specific training may play a contributing role in the preventive strategy to avoid osteoporosis.

Anthropometry↗
PubMed1994

Longus colli has a postural function on cervical curvature.

To determine the postural role of longus colli (LC) and dorsal neck muscles, we have studied the relationship between their cross-sectional areas related to their force of contraction and the lordosis and the length of the cervical spine. This study was carried out in 36 healthy subjects. Muscle cross-sectional areas were measured by computerized tomography. The index of lordosis and the length of the cervical spine were measured on an X-ray profile. The cross-sectional area of LC was correlated to the lordosis index (R = -0.432, p < 0.02) whereas all the other parameters were not correlated. The authors conclude that LC counteracts the lordosis increment related to the weight of the head and to the contraction of the dorsal neck muscles. Postural functions of LC and postcervical muscles are complementary. They form a sleeve which encloses and stabilizes the cervical spine in all positions of the head.

Adult↗
PubMed1993

One-year psoas training can prevent lumbar bone loss in postmenopausal women: a randomized controlled trial.

On the premise that bone response to exercise is locally controlled, we conducted a randomized trial to evaluate the effects of a 1-year training of psoas muscles (treatment group: TG) versus a 1-year training of deltoid muscles (control group: CG) on the lumbar trabecular bone mineral density (TBMD). TBMD was measured with computed tomography scan. Seventy-eight subjects were included and 67 completed the study. Intention to treat analysis revealed no significant change in TBMD from 0 to 12 months. Data analysis in the 67 remaining women, including both assiduous and nonassiduous subjects, revealed greater bone loss in CG than in TG although the difference was not significant. Similar analysis in a subgroup of subjects who performed the exercises assiduously (TG: n = 23, CG: n = 26) showed that the mean bone loss of all four vertebrae from 0 to 12 months was significantly greater in the CG (-8.87 +/- 12.75 mg/cm3, mean +/- SD) than in the TG (0.14 +/- 11.21 mg/cm3, mean +/- SD, P = 0.01). These results suggest that continuous 1-year psoas training can prevent lumbar bone loss in postmenopausal women and support the hypothesis of local action of physical activity.

Bone Density↗
PubMed1991

[Tendinitis of the knee].

The diagnostic criteria for tendinitis of the knee are: (1) strict localization of the pain in the whole length of the tendon from its body to its end; (2) recrudescence of pain during movements that stretch or rub the tendon, and (3) positive local anaesthesia test if needed. Only this approach makes it possible not to miss a tendinitis of the extensor system in a so-called femoro-patellar syndrome, or to misdiagnose a tendinitis of the sartorius, gracilis and semitendinosus muscles when confronted with an osteoarticular pathology of the medial femoro-tibial compartment.

Humans↗
PubMed1990

Method of quantitative anatomical study of the dorsal neck muscles. Preliminary study.

Biomechanical models of the cervical spine require knowledge of the position, size and orientation of the individual muscles that act on the cervical spine. We have developed a technique to stereometrically measure anatomical specimens. The apparatus is composed of three graduated metallic rods, which slide along a fixed support. This method is accurate to map the anatomy of individual muscles and provides quantitative data on their lines of action. Results are obtained from one specimen. The computer processing of the collected data allows formulation of a three-dimensional model of the neck muscles in man.

Biomechanical Phenomena↗
PubMed1989

A morphometric study of the lumbar foramen. Influence of flexion-extension movements and of isolated disc collapse.

The authors undertook a morphometric study of the intervertebral foramina in anatomic specimens of spines unaffected by degenerative lesions. They studied the variations in shape and size of 38 intervertebral foramina during flexion-extension movements and following an isolated disc collapse. The cast technique takes into account the bony prominences, the bulge of the disc anteriorly and of the capsulo-ligamentous structures posteriorly. In flexion, all the diameters of the foramina are maximal. In full extension all the diameters decrease significantly: the pedicles come closer together, the disc bulges posteriorly and the ligamentum flavum is pushed forward by the superior articular process of the underlying vertebra. A disc collapse of 4 mm decreases all the diameters, and in this case lumbar extension results in a sufficient decrease of foraminal diameter to threaten the nerve root.

Female↗
PubMed1989

Strength and cross-sectional area of the dorsal neck muscles.

The maximum isometric strength of cervical extensors was measured in a group of sixteen young healthy subjects. The cross-sectional area was obtained by computerized tomography. A significant positive correlation was found between muscle strength and cross-sectional area. The ratio of strength to cross-sectional area is 10.17N/cm2. This value is similar to that estimated on the quadriceps using similar methods in other studies. Numerous factors are suggested to explain the individual variability of the results even within a homogeneous group; among them, neck morphology is important.

Adult↗
PubMed1988

[Morphological variations of the lumbar foramina during flexion-extension and disk collapse].

The authors have studied, on anatomical preparations, the variations in shape and size of 38 intervertebral foramina during flexion-extension movements, on spines which were free of degenerative lesions; they also studied the same variations following an isolated disc collapse. The cast technique takes into account the bony prominences, the bulge of the disc anteriorly, and the capsulo-ligamentous structures posteriorly. In flexion, all the diameters of the foramina are maximum. In extreme extension, all diameters decrease significantly; the pedicles come closer together, the disc bulges posteriorly and the ligamentum flavum pushed by the superior articular process of the underlying vertebra, projects forward. When the height of the disc is preserved, the reduction in size of the foramen does not compress the nerve root. A moderate disc collapse of 4 mm decreases all the diameters and under those circumstances, lumbar extension results in a sufficient decrease of the diameter of the foramen to threaten the nerve root, even in the absence of posterior articular osteophytes.

Adult↗