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Biomedical subjects

J Dequeker

Publications and source records attributed to J Dequeker.

At least 109 records · Page 6Linked to original sources
PubMed1997

Inverse relationship of interface between osteoporosis and osteoarthritis.

The inverse relationship between osteoporosis and osteoarthritis (OA) was first noticed 20 years ago. The subject, however, remains controversial. Recent observations on bone mineral density (BMD) in large epidemiological population surveys confirmed that cases with generalized OA had significantly increased bone mass at the axial and peripheral skeleton compared to age and sex matched controls corrected for body weight. Because OA cases have significantly increased bone width, BMD at the forearm is not significantly increased in some studies. The association of moderate to severe OA with increased appendicular and axial BMD is comparable to that of other determinants of bone mass, including 10 years of age and 10 kg of body weight, and thus may confer protection against fracture, especially of hip fracture.

Adult↗
PubMed1997

HLA typing in a large family with multiple cases of different autoimmune diseases.

OBJECTIVE: Because of the concurrence, in members of one family, of different autoimmune disorders [rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), psoriasis (PS), and inflammatory bowel disease (IBD)], we investigated the genotypes of each member and compared the results with current knowledge of genetic inheritance of rheumatic and other autoimmune diseases. METHODS: Sera and peripheral blood lymphocytes of 16 family members were collected for HLA typing and investigation. RESULTS: All patients with RA were DR4 positive ad 4 of 5 showed the maternal A2B51DR4 haplotype. Two of 3 siblings with the genotype HLA-A2/3, B8/35, DR2/3 had SLE. Patients with IBD and psoriasis shared the haplotype HLA-A3, B35 CW4 DR2. CONCLUSION: The results show that the important role of patients, sex and confirm the association between HLA haplotype and RA or SLE. They support the hypothesis that autoimmunity is a mendelian dominant trait, and that secondary genes, including these of the major histocompatibility complex, confer phenotypic specificity.

Arthritis, Rheumatoid↗
PubMed1997

Total knee arthroplasty in the young rheumatoid patient.

Thirty-four total knee arthroplasties were performed for severe rheumatoid arthritis in 25 patients younger than 45 years. All patients were available for follow-up evaluation at an average of 7.2 years. According to the Knee Society scoring system, the knee score improved from an average of 21 points preoperatively to 85 points at follow-up (p < 0.001). The average functional score improved from 23 points to 87 points (p < 0.001). Average range of motion improved from 71 degrees to 93 degrees (p < 0.001). Nonprogressive radiolucencies less than 1-mm thick were observed in 6 knees. One knee was revised for severe polyethylene wear; another case was revised for chronic patellar dislocation. Actuarial survivorship analysis estimates a 97% survivorship after 5 years and 90% after after 10 years. In young rheumatoid patients, total knee arthroplasty can therefore be considered as a reliable procedure, with satisfactory results during at least the first 5 to 10 postoperative years.

Actuarial Analysis↗
PubMed1997

Fluoride kinetics of the axial skeleton measured in vivo with fluorine-18-fluoride PET.

UNLABELLED: The aim of this study was to quantify regional bone blood flow and influx rate with PET and [18F]fluoride in patients with metabolic bone disorders. METHODS: Dynamic imaging of the spine or pelvis was performed after administration of 300-370 MBq of 18F-. Plasma clearance of 18F- was determined in blood sampled from the radial artery. A three-compartment model was used to estimate the regional flow and fluoride influx rate. RESULTS: In this preliminary study, fluoride flux (in micromol/min/liter) could be measured regionally. The flux was consistent with the pathophysiology of the studied metabolic disorders and allowed the various disease states to be distinguished. Bone blood flow and influx rate were low in osteoporosis (in the "normal-appearing" bone) and high in Paget's disease. CONCLUSION: With PET and [18F]fluoride, local bone blood flow and fluoride influx rate can be quantified in patients in vivo. Metabolically active zones have an increased influx rate and an accordingly increased flow. In principle, this technique permits classification of bone disorders and has potential for the monitoring of therapy response in metabolic bone disease.

Adult↗
PubMed1996

Effects of recombinant human growth hormone and insulin-like growth factor-I, with or without 17 beta-estradiol, on bone and mineral homeostasis of aged ovariectomized rats.

This study aimed to evaluate whether recombinant human growth hormone (rhGH) or insulin-like growth factor-I (rhIGF-I) can reverse or prevent further bone loss in aged osteopenic ovariectomized (OVX) rats and to compare their effects with those of 17 beta-estradiol (E2). Twelve-month-old rats were OVX, remained untreated for 8 weeks, and subsequently received daily subcutaneous (SC) injections of rhGH (75 micrograms/day), rhIGF-I (250 micrograms/day), E2 (1.5 micrograms/day), and their respective combinations during 8 weeks, and were then compared with sham-operated, pretreatment OVX, and saline-treated OVX rats. A single sc injection of rhGH resulted in peak hGH concentrations after 90 minutes, with a half-life of 124 minutes; the highest plasma IGF-I concentrations were reached 45 minutes after rhIGF-I injection (+57% vs. baseline) with a gradual decline thereafter. Measurements included: biochemical parameters of bone remodeling (plasma osteocalcin and urinary pyridinolines); histomorphometry of proximal tibial metaphysis; DXA of femur; biomechanical analysis of femur and fifth lumbar vertebra (L5); plasma 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), and calbindin-D9K in duodenal mucosa. Whereas all E2-treated OVX rats had much suppressed bone remodeling, rhGH or rhIGF-I had no effect on any biochemical or histomorphometrical parameter of remodeling. The bone mineral density (BMD) at the distal femoral metaphysis as well as parameters of strength at L5 were maintained at pretreatment values in OVX rats treated with E2, GH, or IGF-I, but not in saline-treated OVX rats; their effects were not additive, however. Trabecular bone volume in the tibial metaphysis was also higher in rats treated with these agents than in saline-treated rats, but this was more apparent at the primary than at the secondary spongiosa, suggesting that their mechanism of action is on primary spongiosa formation or breakdown. E2 alone was ineffective to augment the BMD at the femoral diaphysis; however, the diaphyseal BMD was 12-14% higher (p < 0.01) after 8 weeks of GH treatment than in pretreatment or saline-treated OVX rats and sham-operated rats, while IGF-I was less effective than GH, GH or IGF-I treatment had no effect on plasma 1,25(OH)2D3 or duodenal calbindin-D9K concentrations, but the combination of GH or IGF-I with E2 potentiated the effect of E2 to stimulate calbindin-D9K concentrations and urinary calcium excretion, indicating "hyperabsorption hypercalciuria." In conclusion, the administration of rhGH and rhIGF-I, like that of E2, into aged OVX rats prevents further loss of bone mass and strength at sites containing trabecular bone. In addition, rhGH increases cortical bone mass above pretreatment values.

Absorptiometry, Photon↗
PubMed1996

Lack of in vitro evidence for storage of 1,25-dihydroxycholecalciferol (1,25(OH)2D3) and 1,25(OH)2D3 binding protein in skeletal matrix.

A few studies have reported on the measurement of 1, 25-dihydroxycholecalciferol (1,25(OH)2D3) in bone, using chloroform/methanol extraction and radioreceptor assay. As the significance of bone 1,25(OH)2D3 content was not defined in any of these reports, the objective of the current investigation was to determine whether 1,25(OH)2D3 may be stored in skeletal matrix. Bone powder samples from the iliac crest were extracted in ethylacetate/cyclohexane and 1,25(OH)2D3 isolated from the extract by means of Sephadex LH-20 and high pressure liquid chromatographic separation and subsequently measured by radioimmunoassay (RIA). Within the detection range of the RIA, no 1,25(OH)2D3 could be measured, suggesting that 1,25(OH)2D3 is not stored in skeletal matrix. Vitamin D bone concentrations previously measured may therefore have reflected plasma contamination. Consistent with this hypothesis, only traces of skeletal 1,25(OH)2D3 binding protein were measured when compared with serum values. Although 1,25(OH)2D3 may act as a potential local determinant of bone remodeling, there is no evidence supporting a delayed paracrine function by matrix-derived 1, 25(OH)2D3.

Adult↗
PubMed1996

Hydroxyprolinuria in normal Zairean children.

Hydroxyprolinuria has been measured in 378 normal Zairean children aged between 3 and 13 years using the Kivirikko's method; 192 of them were boys and 186 were girls. Results show an age-related increase of urinary excretion of hydroxyproline in both sexes, girls having higher absolute values than boys. However, this difference is pronounced when values are corrected according to body size. Our values are slightly higher than those found in the literature.

Adolescent↗
PubMed1996

Effects of low-dose long-term sodium fluoride preventive treatment on rat bone mass and biomechanical properties.

Effects of fluoride on bone strength and cortical bone mass remain controversial. We compared 9-month, low-dose sodium fluoride (NaF) treatment with estrogen replacement therapy. Female Wistar rats 4.5 months old were divided into baseline, sham-operated (sham), sham-treated with NaF at 0.5 mg NaF/kg/day in drinking water, and ovariectomy (OVX), OVX treated with NaF and with estrogen. Bone mass was measured by dual X-ray absorptiometry (DXA) in vitro. Dimensions of the first lumbar vertebral body (L1) were determined by radiogrammetry. The right femur was processed undecalcified to obtain a midshaft cross-section to determine cross-sectional moments of inertia (CSMIs). L1 compressive test and left femoral torsional test were performed. OVX induced significant bone loss in L1 and femoral midshaft. Bone mass was increased to a greater extent in NaF-treated rats than in rats receiving estrogen replacement therapy. Femoral CSMIs in OVX rats, both L1 sizes and femoral CSMIs in NaF-treated rats, were significantly increased. Estrogen treatment had the least dimension expansion. OVX significantly decreased L1 compressive variables. There was no statistical difference in compressive parameters between NaF-treated groups and controls. OVX significantly increased femoral torsional strength but NaF treatment did not. Bone fluoride content was significantly increased after treatment with NaF. No significant difference in bone mineralization degree (ash and calcium) was found between treated and control rats. The discrepancy that an increase in bone mass and geometric properties in both trabecular and cortical bones by low-dose, long-term NaF treatment did not increase vertebral strength nor proportionally improve femoral strength indicated that the bone intrinsic biomechanical properties could be changed by NaF treatment.

Animals↗
PubMed1996

Radial cortical and trabecular bone densities of men and women standardized with the European Forearm Phantom.

We previously showed that it is possible to cross-calibrate peripheral bone densitometers using the European Spine Phantom (ESP). We have now performed a multinational study of cross-calibrated radius bone density based on normal subjects of both sexes in eight European centers. Six centers were equipped with machines made by Scanco or Stratec for determining distal radial trabecular bone density by quantitative computed tomography (QCT) and two were equipped with Lunar SP2 single photon absorptiometry (SPA) equipment for measuring midshaft cortical bone density. Subjects recruited ranged from 20 to over 80 years of age. Over one hundred and fifteen men were studied by QCT and a different cohort of 104 men were studied with SPA; the equivalent figures for women were 235 and 123. Reference ranges were derived for bone density against age for each of the four groups, and their applicability is discussed in relation to between-center differences in the results obtained. There were insignificant differences (P > 0.05 with Bonferroni correction) between centers in the values obtained by QCT in the different populations. However, there were considerably larger and highly statistically significant differences between midshaft cortical bone density values of about 10% of overall means between subjects from eastern Finland and central Belgium (P < 0.001), with higher Finnish values. Women had considerably lower radial trabecular bone density values than men at all ages, a result that differentiates the radius from the spine. This sex difference widened after menopause. These results have important implications for understanding the contribution of bone density to the differential risk of Colles' fracture in the two sexes and suggest that further work is needed to establish young normal reference ranges for radial bone density in Europe.

Absorptiometry, Photon↗
PubMed1996

Effect of salmon calcitonin on femoral bone quality in adult ovariectomized ewes.

The aim of this study was to evaluate the effect of intermittent calcitonin on femoral bone quality in adult ewes from the time of ovariectomy. Six months after the start of the experiment, bone density measurements and mechanical testing (torsion and resonant frequency analysis of the diaphysis and compression of an excised trabecular bone cylinder from the femoral neck) were performed in sham-control and ovariectomized (OVX) ewes treated with placebo or salmon calcitonin (50 or 100 units, 3 times/week). Crystallinity of bone was evaluated by measuring X-ray diffraction line broadening. After OVX, a nonsignificant bone loss was found at all measured sites in the femur (-3 to -9%) together with a decreased biomechanical competence in the trabecular bone (compressive strain -28%, P < 0.05). Treatment with salmon calcitonin, 50 or 100 IU subcutaneously three times a week from the time of ovariectomy, resulted in a significant dose-dependent preservation of bone strength in the trabecular bone of the femoral neck compared with OVX. No adverse effects of calcitonin were observed on bone crystal composition as assessed by diffractiometry. We conclude that in adult ewes intermittent calcitonin treatment from the time of OVX was associated with a significant preservation of cancellous bone strength and strain in trabecular bone of the femoral neck, without affecting crystalline properties of bone.

Animals↗
PubMed1996

Radiological prevalence of lumbar intervertebral disc calcification in the elderly: an autopsy study.

OBJECTIVE: The objective of this study was to investigate the in vitro radiological prevalence of lumbar intervertebral disc calcification (IDC) in the elderly and its relation to osteoarthritis (OA). MATERIALS AND METHODS: Lumbar spine segments comprising L2-4 were resected from 60 cadavers (30 males, 30 females; average age 67 years) and investigated with high-contrast radiography and computed tomography (CT). RESULTS AND CONCLUSIONS: IDC was found in 58.3% of the patients using high-contrast radiography and in 46.7% of the patients using CT. IDC prevalence and OA grades in the lumbar spine and right hand were found to increase with age. IDC prevalence and OA grades for L2-3 were not significantly different from those for L3-4. No significant sex difference was found for IDC prevalence and OA grades. The results indicate that IDC is significantly underestimated in vivo by conventional radiography and the intervertebral disc calcification may be a common phenomenon in aging. The exact relation IDC to OA remains undetermined.

Adult↗
PubMed1996

Clinical utility of bone mass measurements in adults: consensus of an international panel. The Society for Clinical Densitometry.

Low bone mass predicts future fracture risk as well as high cholesterol or high blood pressure can predict the risk of heart disease or stroke. Prevention of the first fracture should be a clinical goal. In patients without fractures, osteopenia and osteoporosis can be diagnosed based on the extent of reduction in bone mass below mean peak bone mass of young healthy individuals. As bone mass decreases, fracture risk increases exponentially. Clinical situations in which an assessment of bone mass and fracture risk affects therapeutic decisions include estrogen deficiency, vertebral abnormalities, radiographic osteopenia, asymptomatic primary hyperparathyroidism, and long-term corticosteroid therapy. Serial measurements can also be used to monitor the effects of osteoporosis treatments. The appropriate technique and skeletal site for bone mass measurements should be chosen based on the patient's circumstances and the precision of measurement. A clinical interpretation can enhance the value of computer-generated bone mass measurement reports and improve decision making.

Absorptiometry, Photon↗
PubMed1996

Strategies for the prevention of senile (type II) osteoporosis: an update.

Hip fractures in the elderly represent a global issue, associated with significant morbidity and mortality. Considering the magnitude of the problem, any substantial reduction in the hip fracture burden depends on prevention. In view of the complex pathogenesis of senile (type II) osteoporosis, preventive strategies should focus on the frequency of falling in the elderly as well as on the prevalence of compromised femoral integrity as a consequence of bone loss. Although many risk factors for senile osteoporosis are potentially preventible or reversible with targeted interventions, the beneficial effects of most strategies have not yet been adequately documented, indicating the need for additional long-term controlled studies.

Accidental Falls↗
PubMed1996

A comparison of time-domain and frequency-domain approaches to ultrasonic velocity measurement in trabecular bone.

Different methods for ultrasonic velocity determination using broad-band pulse transmission have been investigated in 70 human calcanae in vitro. The work took place within the context of the EC BIOMED1 concerted action Assessment of Quality of Bone in Osteoporosis. Ultrasonic velocities were determined using three different transit time definitions: first arrival (TTV1), thresholding (TTV2), and first zero crossing (TTV3). Phase velocity (PV) was determined over a range of frequencies from 200 to 800 kHz using a new phase spectral analysis technique. The different velocity measurements were compared in terms of their magnitudes and their inter-correlations. There were significant differences of up to 260 m s-1 between different transit time velocities (p < 0.0001), indicating the sensitivity of the measurement to the arrival criteria used. Phase velocities were lower than all of the transit time velocities (p < 0.0001) and decreased with increasing frequency (p < 0.005). A strong correlation (r2 = 0.968) was observed between PV at 400 kHz (PV400) and TTV3, with much weaker correlations between PV and the other transit time velocities. Reproducibility for transit time velocity measurement was optimal for TTV3 (coefficient of variation, cv = 0.41%), and for PV it was optimal at 600 kHz (cv = 0.34%). These data indicate that transit time measurements may be subject to errors due to the modification of the pulse shape during propagation through bone by attenuation and dispersion. Velocity measurement by phase spectral analysis appears to offer advantages over the transit time approach, and should be the method of choice for velocity measurement in trabecular bone. Where transit time velocity measurements are made, the first-zero-crossing criterion appears to be have some advantages over other arrival criteria. We also note that PV measurements provide new information on dispersion which could prove to be relevant to the structural and mechanical characterization of trabecular bone.

Adult↗