Relationship between bone fluoride content and histological evidence of calcification defects in osteoporotic women treated long term with sodium fluoride.

Fluoride treatment is used to increase bone formation and cancellous bone mass in patients suffering from postmenopausal osteoporosis with vertebral fractures. Patients submitted to similar therapeutic protocols have shown various histological responses to the treatment, some developing calcification defects and others not. In fact, the bone histological response to fluoride salts depends on the cumulative uptake of fluoride by bone. To clarify the relationship between the presence of calcification defects (identified by the presence of mottled bone and linear formation defects) and the bone fluoride content, a retrospective study was performed on 29 women with type 1 osteoporosis and treated for several months (11-24) with sodium fluoride (50 mg/day), calcium and vitamin D. Bone fluoride content always significantly increased after treatment, but it was significantly higher in patients showing calcification defects than in those having no defects. These differences between the two groups of patients were not due to differences in clinical details (no significant differences concerning age, duration of treatment, total amount of fluoride ingested, renal function) or in their bone remodelling activity. Thus, it may be hypothesized that the high bone fluoride uptake is due to different individual responses from one patient to another concerning the bioavailability of the same dose of fluoride. This is difficult to predict, except by testing the individual bioavailability of the compound to be used in each patient before starting long-term treatment.

Effects of the calcium channel blocker nifedipine on epiphyseal growth plate and bone turnover: a study in rabbit.

The potential effects of a calcium channel blocker (nifedipine) on epiphyseal growth plate and bone remodeling have been investigated in growing rabbits. The treated group received 6 mg/kg/day nifedipine twice daily by gavage for 10 weeks. An untreated group was used as control; with this dose, neither toxic effects nor decrease in the body weight have been observed. No modifications of blood phosphocalcic parameters have been found. In the treated group there is a significant lower cancellous bone volume, lower osteogenesis, shorter labeled perimeters, and lower mineral apposition rate than in the control group. Epiphyseal growth plate thickness is lower than in the untreated animals and considerable morphological changes are observed in the growth zone compared with the control group. A decrease in the growth of humerus length was found. In conclusion, nifedipine affects bone physiology, especially with consequences on bone growth. These effects appear to be quantitatively important, and there is the possibility of bone side effects on therapeutic use in humans, especially in young subjects.

[Study of mastocytes in 1298 bone biopsies. Relationship between mastocytes and osteoporosis]. / Etude des mastocytes sur 1,298 biopsies osseuses. Relations entre mastocytes et ostéoporose.

The relationship between the bone damage in systemic mastocytosis and reactional mastocytosis is still poorly understood. The purpose of this study was to determine the incidence of excessive mastocytes in a series of bone biopsies and their significance in cases of osteoporosis. The mastocytes were routinely counted in 1,298 successive biopsies stained with May Grumwald Giemsa: 131 biopsies had more than 5 mastocytes/mm2, i.e., 10% of all samples for all diagnoses combined. In 11 patients (13 bone biopsies) with a large excess of mastocytes (more than 15/mm2) and osteoporosis, the biopsies were examined again to look for mastocytic nodules suggesting bone mastocytosis: mastocytic nodules of this type were found in only 4 cases. The mastocyte is an active cell which may play a role in bone metabolism through the intermediary of its mediators. In osteoporosis, the incidence and significance of excessive mastocytes is not yet understood; this excess of mastocytes appears to correspond to reactive mastocytosis rather than systemic mastocytosis.

[Effect of a calcium inhibitor, verapamil, on the development of heterotopic ossifications. An experimental study in rats]. / Effet d'un inhibiteur calcique, le vérapamil, sur le développement des ossifications hétérotopiques. Etude expérimentale chez le rat.

After division of the tendo achilles in rats heterotopic bone forms in the muscle and in the tendon stumps. Tenotomy was performed in 26 male rats. Thirteen received Verapamil (36 mm/Kg) for six days per week for five months, and the remainder were not given this drug. The onset of heterotopic ossification was monitored by monthly x-rays. After five months the animals were killed and the sectioned tendons examined microscopically. The radiographs had shown that the amount of ossification was less in rats treated with Verapamil. This was confirmed at microscopy, but examination of the sections under polarised light showed that the ratio of lamellar to woven bone was the same in the two groups. Verapamil appeared to reduce the amount of heterotopic bone formation but did not influence the substitution of woven by lamellar bone.

Bone involvement in primary hemochromatosis and alcoholic cirrhosis.

Biochemical indexes of bone metabolism, bone mineral density, and histomorphometry were evaluated in 14 male patients with noncholestatic cirrhosis due to primary hemochromatosis (six cases) or to chronic alcohol abuse (eight cases), and in 30 male controls of similar age. Alkaline phosphatase in alcoholic patients was significantly higher than in controls (mean +/- SD 50.4 +/- 33.7 vs 33.0 +/- 7.1 U/L, p less than 0.01), as was urinary hydroxyproline in both hemochromatotics and alcoholics (mean +/- SD, 44.3 +/- 8.4 and 40.4 +/- 16.8, respectively, vs 30.1 +/- 4.5 mg/g, p less than 0.001 and p less than 0.005). Bone mineral density was significantly lower in hemochromatotics than in alcoholics and controls (mean +/- SD, 591 +/- 90 vs 765 +/- 87 and 759 +/- 34 mg/cm2, respectively, p less than 0.005 and p less than 0.001). At bone biopsy, trabecular osteoporosis was observed in two hemochromatotics and four alcoholics, and osteomalacia was seen in another alcoholic. Overall densitometric and histomorphometric findings indicate a derangement of trabecular bone in both alcoholic and hemochromatotic cirrhosis, whereas cortical osteoporosis seems limited to hemochromatotic patients.

[Microradiographic study of iliac bone biopsies taken after treatment of postmenopausal osteoporosis with sodium fluoride. Histomorphometric correlations]. / Etude microradiographique de biopsies osseuses iliaques prélevées après traitement de l'ostéoporose post-ménopausique par le fluorure de sodium. Corrélations histomorphométriques.

Thirty seven female patients with osteoporosis underwent iliac bone biopsy after 10 to 23 months of continuous or discontinuous treatment with sodium fluoride, calcium, and vitamin D. Microradiographs of the biopsies from 13 patients showed one or--more often--several of the characteristic appearances of bone fluorosis: defects in periosteocytic mineralization, unmineralized strips inside the trabeculae of spongy bone, construction of fibrous bone, hypercalcified periosteal apposition. The occurrence of these microradiographic signs of fluorosis does not seem to be linked either to the age of the patients, to the interval elapsed since ovarian function ceased, or to the degree of bone remodelling at the time that treatment was started. Moreover, none of these patients showed signs of even moderate renal insufficiency. Should the development of this fluorosis, which is most frequently clinically asymptomatic, be considered as a condition or as a factor in therapeutic efficacy? Or are the effects detrimental and therefore to be avoided by a reduction in dosage or a change in therapeutic methods?

[Effects of Chiari osteotomy on acetabular development in the growing subject. Experimental study in puppies]. / Effets sur le développement cotyloïdien de l'ostéotomie de Chiari chez le sujet en croissance. Etude expérimentale chez le chiot.

A Chiari osteotomy was performed on 10 dogs aged 2 months in order to assess the risks of mechanical or ischaemic loss of growth potential in the peri-acetabular cartilage. The development of the acetabular roof was studied by radiographs, microradiographs and histological assessment between 2 and 12 months. Apart from a few mechanical complications, the principal findings were the absence of any signs of necrosis, persistence of a strongly osteoblastic roof and readaptation of the trabecular pattern with articular remodelling, provided the mechanical conditions were satisfactory. The osteotomy must be sufficiently low, while remaining extra-articular, and adequate medial shift must be obtained. The interposed capsular tissue can then become dense and fibrous, providing a sliding surface.

[A study of changes in bone mineral content in relation to age, using Cameron's method (author's transl)]. / Variation du contenu minéral osseux en fonction de l'âge. Etude par la méthode de Cameron.

The amounts of calcium present in the skeleton were accurately measured and monitored in 1280 women and 418 men, using Cameron's photon absorption method of bone mineral content measurement. Used as a screening test on the first visit, this method becomes an excellent means of longitudinal surveillance after assessment of the calcium/phosphorus balance.

[Acceleration of repair of non-unions by electromagnetic fields (author's transl)]. / Résultats de la stimulation par champ électromagnétique de la consolidation des pseudarthroses. A propos de 37 cas.

This work deals with the results obtained by four French orthopaedic departments using the electromagnetic field stimulation for non union treatment. This is the method established by A. Bassett. 37 cases are studied, the results are known for 35 of them with 6 failures and 29 successes. The failures can be explained for four of them by a bad application of the device. Concerning the 29 successful cases, the role of the stimulation is discussed. Discarding those who have been treated a short time after a surgical procedure, those who have been immobilized more than 6 months and those where the non union could have been a delayed union, it remains 14 successful cases apparently undisputable. For them the role of the electromagnetic field stimulation seems real.

[Modification of skeletal maturation in Perthes' disease (author's transl)]. / Ostéochondrite de la hanche et maturation osseuse.

The authors have observed 34 cases of Perthes' disease to try to discover whether the lesion is an isolated epiphyseal dystrophy or the local complication of a more generalised disease. They found that most of the patients show retardation of skeletal maturation without any of the usual pathological explanations. They consider that perthes' disease is associated with multiple factors including genetic and endocrinological ones causing generalised of cartilage.

[Tibial lengthening by transepiphyseal distraction of the proximal growth plate. An experimental study in the rabbit (author's transl)]. / Allongement tibial par élongation du cartilage de croissance tibial supérieur. Etude expérimentale chez le lapin.

Lengthening by transepiphyseal distraction has been used in man by several authors, but experimental results are variable. In this study twenty young rabbits have been submitted to elongation, half with circumferential metaphyseal release, half without. Lengthening obtained at the end of the growing period has been poor or negative in case with periosteal release, a little better without this incision.