Bone
It has recently been shown that following treatment with colony-stimulating factor-1 (CSF-1) the osteopetrotic condition in toothless (tl) rats greatly improves and growth is accelerated. We have examined the effects of such treatment on the microvasculature of the distal femoral chondro-osseous junction, a site where bone growth in length is coordinated with angiogenesis. Vascular casts and ultrastructural...
Insulin-like growth factors (IGFs) are among the most abundant growth factors present in bone. In vitro, bone-derived cells both produce and respond to IGFs I and II, suggesting that these growth factors play an autocrine role in the regulation of bone turnover. In vivo, however, particularly in adult bone, their sites of expression have not been well documented. We have used, therefore, the technique...
Parathyroid hormone-related protein (PTHrP) is synthesized by a variety of tumors and is thought to be the main cause of the clinical syndrome of humoral hypercalcemia of malignancy (HHM). In addition to its parathyroid hormone (PTH)-like actions, novel actions of PTHrP on placental calcium transport and inhibition of in vitro osteoclast activity have been demonstrated. The fact that osteoblasts...
Our aim was to evaluate the role of cortical bone in resistance to compression in the human radius. Thirty-three left cadaver forearms were scanned on an XCT 960 Stratec CT scanner. Cortical density and cortical thickness were measured at the junction of the middle and distal third of the radius. Subsequently, 2-cm-high cylindrical specimens, centrated on the level of the CT slice, were cut. After...
Replacement of dual energy X-ray densitometry (DXA) equipment may be necessary in many labs with time, or new equipment may be added. In this context we compared patient scans between a Hologic QDR-1000W and a QDR-2000 (n = 29-43, depending on anatomic region) and between QDR-2000 single beam (SB) and fan beam (FB) modes (n = 40-62) as a quality control measure. A total of 83 subjects (79 females...
Bone resorption resulting from the metastatic human melanoma cell line (A375) was investigated morphologically using an experimental model of bone metastases in nude mice. An injection of A375 (1 10 5 ) in the left ventricle produced multiple osteolytic lesions. Many TRAPase-positive multinucleated cells, identified by EM as osteoclasts, were observed on the bone surface at the site of...
The activity of a novel calcitonin SB 205614 was compared with salmon calcitonin (sCT) and (Asu 1 , 7 )-eel calcitonin (ELC) in six different models of osteoclastic bone resorption in vitro and in vivo. SB 205614 is an ELC analogue that has an acetylenic bridge instead of the natural disulphide bridge, rendering the molecule more stable biologically than sCT and equally stable to ELC...
Bone mineral content (BMC) and density (BMD) were measured by dual-energy X-ray absorptiometry in two subtypes of autosomal dominant osteopetrosis (ADO). Both types have been radiologically characterized by diffuse symmetrical osteosclerosis, but with characteristic differences. Increased thickness of the cranial vault is a typical finding in type I ADO, whereas endobones in the pelvis and end-plate...
Platelet-derived growth factor (PDGF) has been shown to have effects on bone and cartilage cells in vitro, but its role in vivo in bone repair is not clear. We studied biopsy material from 16 normally healing fractures at a variety of times after injury, using immunohistochemistry for PDGF and in situ hybridization for PDGF A and B chains. PDGF A-chain gene was found to be expressed by many cell types...
The effects of brief' daily exercise on bone mineral density (BMD) were assessed in a randomized controlled trial in 44 healthy postmenopausal women using weight-bearing exercise in a regimen adapted from osteogenic protocols reported in animal studies. BMD was assessed masked using dual energy X-ray absorptiometry at 0, 6, and 12 months. The sites assessed were the proximal femur (neck, Ward's triangle,...
Pyridinoline (Pyr), a specific bone resorption marker, is usually assessed in urine by high-performance liquid chromatography (HPLC) after acid hydrolysis and a prepurification step. Immunoassays have been developed to measure urinary Pyr directly. Here we developed and evaluated an enzymelinked immunosorbent assay (ELISA), specific for the urinary free Pyr form, in normal adults and in patients with...
Procollagen and proteoglycan biosynthesis was defined in long-term culture of a human osteogenic sarcoma cell line, SAOS-2. An osteoblast phenotype was maintained by these cells up to 40 days post-confluent in the presence of ascorbic acid. Under these conditions, cells deposited around them an extensive collagenous matrix that was able to mineralize in the presence of an exogenous phosphate donor...
The purpose of this study was to define the bone metabolic properties during the postfracture period in elderly women with hip fracture. Osteocalcin (Oc), a marker of bone formation, was measured in 58 women with hip fracture (77 +/- 7 years) admitted to the hospital from their own homes. Serum samples were taken on average 5 h (range 1-21) from fracture and at follow-up, on average 4.6 months later...
We compared the effects of synthetic human parathyroid hormone (1-34) (hPTII[1-34]) on rat bones when administered by intermittent injection and by continuous infusion for 4 weeks. Continuous infusion of hPTH(I-34) caused a dose-dependent decrease in the dry weight of the femur and a hyperparathyroidism-like condition in the high-dose group (214 ng/kg/h). In this group, although bone morphology was...
Bone morphogenetic proteins (BMPs) play a critical role in early skeletal development. BMPs are also potential mediators of bone response to mechanical loading, but their role in later stages of bone growth and adaptation has yet to be studied. We characterized the postcranial skeletal defects in mature mice with BMP deficiency by measuring hind-limb muscle mass and long bone geometric, material,...