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Claude Laurent Benhamou

Publications and source records attributed to Claude Laurent Benhamou.

8 recordsLinked to original sources
PubMed2006

Estimation of the 3D self-similarity parameter of trabecular bone from its 2D projection.

It has been shown that the analysis of two dimensional (2D) bone X-ray images based on the fractional Brownian motion (fBm) model is a good indicator for quantifying alterations in the three dimensional (3D) bone micro-architecture. However, this 2D measurement is not a direct assessment of the 3D bone properties. In this paper, we first show that S(3D), the self-similarity parameter of 3D fBm, is linked to S(2D), that of its 2D projection, by S(3D)=S(2D)-0.5. In the light of this theoretical result, we have experimentally examined whether this relation holds for trabecular bone. Twenty one specimens of trabecular bone were derived from frozen human femoral heads. They were digitized using a high resolution mu-CT. Their projections were simulated numerically by summing the data in the three orthogonal directions and both 3D and 2D self-similarity parameters were measured. Results show that the self-similarity of the 3D bone volumes and that of their projections are linked by the previous equation. This demonstrates that a simple projection provides 3D information about the bone structure. This information can be a valuable adjunct to the bone mineral density for the early diagnosis of osteoporosis.

Algorithms↗
PubMed2006

Imaging techniques for evaluating bone microarchitecture.

At present, fracture risk prediction in the individual patient relies chiefly on bone mineral density (BMD) measurements. However, many lines of evidence indicate that the decreased bone strength characteristic of osteoporosis is dependent not only on BMD, but also on other factors, most notably bone microarchitecture. Here, we review available tools for characterizing trabecular microarchitecture (in terms of morphology, topology, and texture) and for obtaining 2D and 3D images (using radiography, computed tomography, and magnetic resonance imaging). Bone microarchitecture imaging is a noninvasive method that may improve fracture risk prediction in the individual patient, shed light on the pathophysiology of osteoporosis, and help to monitor the effects of treatments. Among the various methods available to date, magnetic resonance imaging has the advantage of involving no radiation exposure, although its limited availability restricts its usefulness for studying vast populations. Regardless of the methods selected to assess bone microarchitecture, there is a need for validated standardized parameters capable of improving fracture risk prediction in longitudinal studies.

Bone Density↗
PubMed2006

Effect of a six-month training programme on the physical capacities of Romanian schoolchildren.

AIM: To analyze the effects of a training programme on the motor performance of Romanian schoolchildren. METHODS: A total of 178 boys (9.5+/-0.8 y, 34+/-9 kg, 137.6+/-8 cm) and 192 girls (9.6+/-0.4 y, 32.7+/-7.6 kg, 136.9+/-7.5 cm) were randomly selected for the training group (TG) (n=198, 109 girls, 89 boys) and control group (CG) (n=172, 83 girls, 89 boys). The TG completed a 6-mo extracurricular training programme (two 50-min sessions per week) involving moderate-intensity impact exercises. At baseline and at follow-up, the EUROFIT tests were administered, and body composition, skeletal maturation and BMI were calculated. RESULTS: At baseline there were no differences in physical characteristics between TG and CG. With the exception of cardiorespiratory endurance, both groups improved motor performances at follow-up. However, for TG boys the improvement was greater than for CG boys in the plate-tapping (+37.2%), sit-up (+20.4%), standing broad-jump (+13%) and shuttle-run tests (+3.8%). TG girls improved more than CG girls only in the standing broad-jump (+18.8%) and shuttle-run (+8.5%) tests. CONCLUSION: Boys and girls in trained groups demonstrated greater increases in some tests of motor performance compared to their untrained peers. Two extra sessions of physical education per week were sufficient to elicit improvements in a number of components of motor fitness.

Child↗
PubMed2004

Dercum's disease (adiposis dolorosa): a new case-report.

UNLABELLED: Dercum's disease, or adiposa dolorosa, is a rare condition characterized by the development of multiple painful subcutaneous lipomas. Postmenopausal women are selectively affected. The ankle area is an uncommon site of involvement. We report a case with lipomas about the ankle, and we review the relevant literature. CASE-REPORT: This 46-year-old perimenopausal woman receiving follow-up for depression presented in December 1997 for swelling and mechanical pain in the right ankle. Lumps behind and under the malleoli were removed surgically and found to have the typical histological features of lipomas. In January 2000, a lump developed behind and under the malleoli of the left ankle, and the lumps on the right recurred. The physical examination showed obesity, with a body mass index of 32.04 kg/m(2). Firm, mobile, painless lumps were felt under and behind the malleoli on both sides. The ankles were painful, although range of motion was normal. Examination of the back found two similar lumps. The erythrocyte sedimentation rate was 10 mm/h and the C-reactive protein level was 6 mg/l. Serum lipid levels were normal. Findings were normal from plain radiographs of the ankles. Ultrasound scanning of the ankles confirmed that the lumps were composed of adipose tissue. Magnetic resonance imaging visualized an arc-shaped lipomatous mass on the left. Whole-body bone density measurement found an increase in fat mass of the lower limbs with normal bone mass. The ankle lipomas were removed surgically. At last follow-up 18 months later, she was free of recurrence. DISCUSSION: Dercum's disease is a rare condition of unknown etiology characterized by multiple, often painful lipomas. Paresthesia in the overlying skin is common. Lipomas about the joints cause mechanical arthralgia. The diagnosis, which is often delayed, rests on ultrasonography and, above all, magnetic resonance imaging. A combination of medications, surgery, and psychiatric care is usually needed. The treatment aims at relieving the pain and restoring a normal appearance.

Adiposis Dolorosa↗
PubMed2002

Effects of chronic intensive training on androgenic and cortisol profiles in premenarchal female gymnasts.

The effect of intensive exercise training on urinary androgen and cortisol excretions in prepubertal girls of various ages was tested in competitive premenarchal gymnasts ( n=56) and in age-matched controls ( n=53). Both sexual maturation and bone age were assessed. Urinary excretions of androstenedione, dehydroepiandrosterone sulphate (DHEA-S), testosterone and cortisol were determined by radioimmunoassay procedures. The gymnasts were taller [mean (SD) 138.3 (9.0) cm vs 144.7 (8.3) cm; P<0.001] and lighter [32.0 (6.9) kg vs 36.7 (8.2) kg; P<0.001], and had a lower percentage of fat mass [16.8 (2.2)% vs 22.5 (6.6)%; P<0.0001] than the controls. There was no difference between groups in urinary testosterone, cortisol and DHEA-S levels, while androstenedione levels were significantly lower in gymnasts than in controls [mean (SEM) 187.10 (18.00) nmol/24 h vs 256.50 (15.00) nmol/24 h; P<0.01). There was no difference in the regression slopes between the two groups for all hormonal values. In conclusion, these results suggest that during the prepubertal period, intensive training alters only urinary androstenedione concentrations in girls.

Adolescent↗