Bone
The effect of low-energy laser (He-Ne) irradiation on bone repair in the tibia of the rat after hole injury was investigated using biochemical and quantitative histomorphometrical methods. The activity of alkaline phosphatase (ALP) showed a sharp peak at 6 days post-injury and a lower peak at 12 days. The overall kinetics of tartrate-resistant acid phosphatase (TRAP) activity coincided with that...
The biomechanical repercussion of the corticoid-induced osteopenia (a severe consequence of long-term glucocorticoid therapy) was studied in cortical bone of small rodents. Growing rats receiving 12.5–3200 μg/kg/d of betamethasone (BMS) s.c. for 20 days suffered a log-dose related impairment in body weight gain and in mechanical (fracture load, bending stiffness) and cross-sectional properties (area,...
The biomechanical repercussion of the corticoid-induced osteopenia (a severe consequence of long-term glucocorticoid therapy) was studied in cortical bone of small rodents. Growing rats receiving 12.5-3200 μg/kg/d of betamethasone (BMS) s.c. for 20 days suffered a log-dose related impairment in body weight gain and in mechanical (fracture load, bending stiffness) and cross-sectional properties (area,...
In this study, the correlation between the mineralization of healing bone defects and the osteogenic capacity of the serum was tested in rats. The purpose of the study was to test the hypothesis that during callus formation, some serum factors are consumed. The bone defects in the tibia contained two different implant types, and all sustained juxta-implant fractures. One implant type was the coral...
Short-term exposure to diets high in fat and sucrose can induce hyperinsulinemia, affect calcium and magnesium metabolism, and alter bone mineralization and mechanical properties. The current study focused on the morphological and structural changes that result from long-term exposure to a high-fat sucrose (HFS) diet. Inbred, female Fischer 344 rats were assigned randomly to a low-fat, complex-carbohydrate...
Age-related changes in the biological activity of osteoblastic cells have been studied extensively using histomorphometry, especially in relation to osteoporosis. Nevertheless, the changes occurring in the biological activity of individual osteoblastic cells are not sufficiently clarified by this technique. In the present study, age-related changes in the expression of bone matrix protein mRNAs...
We examined whether 1α-hydroxyvitamin D 3 (1α(OH)D 3 ) is metabolized into 1α,25-dihydroxyvitamin D 3 (1α,25(OH) 2 D 3 ) in bone. Northern blot analysis indicated that the expression of vitamin D 3 25-hydroxylase mRNA was highest in the liver, followed by the duodenum, calvaria, lung, kidney, skin and long bone, and lowest in the spleen. Of the bone...
We examined whether 1α-hydroxyvitamin D 3 (1α(OH)D 3 ) is metabolized into 1α,25-dihydroxyvitamin D 3 (1α,25(OH) 2 D 3 ) in bone. Northern blot analysis indicated that the expression of vitamin D 3 25-hydroxylase mRNA was highest in the liver, followed by the duodenum, calvaria, lung, kidney, skin and long bone, and lowest in the spleen. Of the bone...
It is well established that short-term clearance of an intravenous calcium load in vivo reflects bone uptake. Using results from isotope-dilution experiments with 42 Ca, a 3-h test has been developed to measure a quantity, γ, related to bone accretion. This test is proposed as a useful, clinically applicable measure of bone status. For early times, t, after a bolus of 42 Ca, plasma...
Osteocyte canalicular density (OCD) was evaluated at different levels of the wall of human secondary osteons, in subjects of different ages, to find out whether any correlation exists between the extension of the canalicular network and the exponential decrement of the appositional growth rate (AGR), which has been shown to occur during osteon formation. Scanning electron microscopy (SEM) was used...
To understand the structural changes accompanying estrogen deficiency-induced bone loss, we examined the temporal changes in cancellous bone structure in an animal model of postmenopausal osteoporosis. Matured rats were subjected to bilateral ovariectomy, and groups of eight animals were sacrificed at 5-day intervals. Histomorphometric and trabecular strut analyses of the excised proximal tibia, and...
Age-related changes in the biological activity of osteoblastic cells have been studied extensively using histomorphometry, especially in relation to osteoporosis. Nevertheless, the changes occurring in the biological activity of individual osteoblastic cells are not sufficiently clarified by this technique. In the present study, age-related changes in the expression of bone matrix protein mRNAs in...
Unfractionated mouse long-bone cells prestimulated with rat parathyroid hormone (PTH) for 7 days (PTH-prestimulated long-bone cells; PTH-psLB cells) contained about 20% tartrate-resistant acid phosphatase (TRAP)-positive mononuclear cells and about 0.2% TRAP-positive multinucleate cells. When PTH-psLB cells (1.0 x 10 5 /slice) were cultured on dentine slices, about 100 resorption lacunae...
Abuse of alcohol has been found to be an important risk factor for fractures and osteoporosis, and tissue culture experiments have indicated that low concentrations of ethanol can affect bone formation and resorption. This study investigated direct effects of ethanol on bone cells using an in vitro resorption assay. Osteoclasts from long bones of 19-day prehatch chicks were seeded onto slices of dentine...
Investigating the potentiality of cord monocytes to differentiate toward osteoclast-like cells (OCL) in vitro, we previously reported that in the presence of 1,25(OH) 2 vitamin D 3 (1,25-(OH) 2 D 3 ), multinucleated-cells generated by cord monocyte cultures though displaying morphological features of OCL failed to resorb devitalized bones. We thus hypothesized that...
Osteocyte canalicular density (OCD) was evaluated at different levels of the wall of human secondary osteons, in subjects of different ages, to find out whether any correlation exists between the extension of the canalicular network and the exponential decrement of the appositional growth rate (AGR), which has been shown to occur during osteon formation. Scanning electron microscopy (SEM) was used...
Osteocalcin in the serum reflects bone turnover. It is known that prolonged therapy with glucocorticoids inhibits bone turnover. The aim of this study was to evaluate the osteocalcin level in children with congenital adrenal hyperplasia treated by glucocorticoids and mineralocorticoids and to assess the influence of 1,25(OH) 2 D 3 . The subjects were 75 children with congenital...
Primary oxalosis is a rare congenital disorder characterised by widespread deposition of calcium oxalate crystals throughout the body. In this paper, we describe the development and treatment of hypercalcaemia associated with oxalosis in a child who had undergone renal transplantation, combined liver and kidney transplantation, and two liver retransplant procedures in the past 5 years. Hypercalcaemia...