Bone
The administration of gonadotrophin-releasing hormone (GnRH) analogs to premenopausal women causes hypoestrogenism and bone loss, but the effects on cancellous microstructure have not been determined. In this study we have assessed bone structure in transiliac biopsies obtained from women before and after treatment for endometriosis with GnRH analogs. Twenty-one premenopausal women were studied,...
PTH increases bone mass by stimulating bone formation in vivo, and IGF-I partially mediates the stimulatory effect of PTH on collagen synthesis in vitro. The objectives of this study were to determine if the anabolic effect of PTH in aged rats was diminished by an energy-restricted (ER) diet in which IGF-I levels have been shown to be decreased, and if GH or IGF-I modified the bone response to PTH...
Bisphosphonates have been shown to be effective in suppressing the elevated bone turnover found in Paget's disease of bone. In theory, the major determinants of post-treatment bone turnover are the initial disease activity and the rate of decline in bone turnover with therapy. In the present study, we examined the rate of decrease of alkaline phosphatase and hydroxyproline (expressed as a half-life)...
Alendronate is an aminobisphosphonate that acts as a potent inhibitor of osteoclastic bone resorption. To understand the mechanism of action of alendronate in vivo, in this study we investigated the relationship between distribution of [ 1 4 C]-alendronate in rat bone and its effects on bone resorption in vitro or in rat hypercalcemic models. A single IV dose of 0.05 ∼ 1.25 mg/kg inhibited...
The purpose of this study was to determine whether PTH has anabolic effects on cortical bone in aged ovariectomized (OVX) rats treated during the late stages of estrogen depletion. Groups of OVX rats were untreated for 1 year postovariectomy followed by treatment for 10 weeks with vehicle, estrogen, the bisphosphonate risedronate (NE-58095), calcitonin (CT), PTH, PTH + estrogen, PTH + NE-58095 or...
The aim of this study was to identify and describe possible alterations of bone histomorphometry in patients with human immunodeficiency virus (HIV-1) infection and to assess the relation between these alterations and disease severity. Forty-four HIV-1-infected patients seen successively at our hospital were evaluated for the study. In an attempt to avoid confounding factors as far as possible,...
We investigated the discriminatory ability of dual energy X-ray absorptiometry (DXA) of the lumbar spine in the anteroposterior vs. decubitus lateral projection in 53 elderly women with at least one vertebral fracture and 63 age-matched women without fracture. Twenty-three premenopausal healthy women served as a reference group. Spine measurements were compared to forearm measurements by single...
Newly developed unbiased stereological methods were employed to investigate the effects of estrogen deficiency on the three-dimensional connectivity of vertebral cancellous bone from ovariectomized (OVX) rats. The effects of two classes of antiresorptive agents, estrogen and bisphosphonates, on changes in connectivity in this animal model were also evaluated. Female rats were either sham-operated...
The effect on calcaneal bone loss of interrupting immobilization by daily periods of normal walking was investigated in adult female sheep. The left calcaneus of 28 sheep was protected from normal loading by placing an external fixator across the hock joint, from the tibia to the metatarsus. In vivo strain gauge recordings from 3 animals showed that, at a test location on the calcaneus, this resulted...
Although the effects of vitamin K 2 and vitamin K 1 on bone metabolism have been reported, the difference between them has not been investigated. We now show the effects of menatetrenone, one of the vitamin K 2 homologues, and vitamin K 1 on bone resorption. Menatetrenone at greater than 3 10 - 6 M significantly inhibited the calcium release from mouse...
Both clinical and laboratory studies have shown that the chemotherapy drug, Methotrexate (MTX), has adverse short-term effects on bone. There are no studies that demonstrate the long-term response of bone to MTX. The purpose of this study was to determine the short- and long-term effects of MTX on bone volume, turnover, mineralization and strength. Three-month-old Sprague-Dawley rats were randomly...
In the osteopenic rat model, estrogen deficiency results in increased bone turnover with net bone loss occurring during cancellous modeling. However, estrogen-deficient rats treated with parathyroid hormone (PTH) experience a net gain of bone tissue due to the anabolic effects of PTH. To evaluate the possibility that local insulinlike growth factor I (IGF-I) production modulates the in vivo balance...
We have recently developed an experimental system whereby pins inserted into the seventh and ninth caudal vertebrae of rat tails are used to load the eighth caudal vertebrae (C-8) in compression. In this model, a single 5-min period of dynamic loading, sufficient to induce strains within the range to which bones are exposed under physiological circumstances, stimulates lamellar bone formation in...
In 1991, we reported that hypercalciuria is a common finding in our pediatric patient population with osteogenesis imperfecta (OI) (17 of 47 = 36%). Here, we prospectively screened 12 of these hypercalciuric children, on average 4 years subsequent to the discovery of elevated urine calcium levels, for adverse effects on renal function. Despite an ad libitum decrease since initial investigation of...
We investigated the usefulness of bone density measurements from multiple skeletal sites and calcaneus ultrasound for evaluating the probability of vertebral deformation. Bone mineral density (BMD) was measured at the second metacarpal and middle phalanges using radiographic absorptiometry of hand radiographs, and at the lumbar spine using dual-energy x-ray absorptiometry. Distal radius and proximal...
Numerous methods are currently being employed to estimate completed wall thickness and final erosion depth. Conflicting estimates of calculated bone balance have been obtained from the estimates of wall thickness and erosion depth using these various methods. To assess the utility of two specific methods to estimate wall thickness (polarized microscopy) and erosion depth (lamellar counts), we conducted...
Few studies have analyzed the relationship between ultrasound measurements (US) and corresponding histomorphometric parameters of the calcaneus. To address this question we have compared US and histomorphometric parameters in 17 whole human os calcis from amputation or necropsy. Speed of sound (SOS), broadband ultrasound attenuation (BUA), and bone mineral density (BMD) were measured on the whole...
The vertebral bodies of the complete spine (C-3-L-5) were removed in 26 autopsy cases without evidence for primary or secondary bone disease (13 males aged 19-79 years and 13 females aged 17-90 years). A sagittal segment through the center of all vertebral bodies was embedded undecalcified in hydroxyethylmethacrylate and processed to so-called surface stained block grindings. Histomorphometric analysis...
The effects of basic fibroblast growth factor (bFGF) administered intravenously at dosages of 0.1 and 0.3 mg/kg per day for 7 days to growing rats are reported. Static and dynamic histomorphometry techniques were applied to the microradiographs and undecalcified ground sections of the proximal tibiae and tibial shafts. The bone histomorphometric analyses in the proximal tibia revealed that 0.1 mg/kg...