The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Osteoporotic fractures commonly occur in the elderly. Although current therapies are aimed at the prevention and treatment of osteoporotic fractures, studies examing the fracture healing process in osteoporotic bone are limited. We produced an osteoporotic rat model by ovariectomy (ovx) and maintained a low calcium diet (LCD) in order to evaluate the influence of osteoporosis on fracture healing....
Angiogenesis is essential for bone growth and repair. Recent studies have shown that the endothelial-specific mitogen vascular endothelial growth factor (VEGF) is a key regulator of vascular invasion into the growth plate in infant and adolescent animals. In order to identify mechanisms regulating VEGF-induced angiogenesis in growing bone, we have investigated the expression of the angiopoietins (Ang-1...
Osteocytes play an important role in signaling within bone. Communication of osteocytes with each other and with bone lining cells may have a function in mineral homeostasis and mechanotransduction. However, very little is known of the expression of ion channels in these cells. Using the whole-cell patch-clamp technique, we have detected three types of K + currents in the mouse osteocyte-like...
Paget’s disease of bone (PDB) is one of the most common bone disorders in the western world. PDB is characterized by focal areas of increased osteoclastic bone resorption and bone formation, which leads to the formation of poorly structured bone. These abnormalities of bone turnover and structure predispose affected individuals to various complications including bone pain, deformity, pathological...
Interleukin-13 (IL-13) inhibits cell proliferation and stimulates interleukin-6 (IL-6) formation in isolated human osteoblasts (hOBs). Because the related cytokine, interleukin-4 (IL-4), is known to exert effects similar to IL-13 in other tissues, and because IL-4 has been implicated as a regulator of bone metabolism, we compared the effects of IL-13 and IL-4 on cell proliferation, IL-6 synthesis,...
Cathepsin K (cat K) is the major cysteine protease expressed in osteoclasts and is thought to play a key role in matrix degradation during bone resorption. However, little is known regarding the synthesis, activation, or turnover of the endogenous enzyme in osteoclasts. In this study, we show that mature cat K protein and enzyme activity are localized within osteoclasts. Pulse-chase experiments revealed...
The purpose of this cross-sectional study was to evaluate the effects of human parathyroid hormone (1-84) (hPTH) followed by maintenance administration of 17β-estradiol (E 2 ), risedronate (Ris), or a reduced dose of hPTH (LowPTH) on vertebral body bone mineral density (BMD) and bone strength in ovariectomized (ovx) rats. Eight groups of ovx (219 rats) and one group of intact female rats (48...
Osteolysis is a common complication of tumors that arise in, or metastasize to, bone. The recent discovery of key regulators of osteoclast formation and activity, including receptor activator of nuclear factor of κB ligand (RANKL), RANK, and osteoprotegerin (OPG), may facilitate new treatment regimes for certain tumors associated with excessive bone loss. We recently showed that the stromal cells...
In mature trabecular bone, both density and trabecular orientation are adapted to external mechanical loads. Few quantitative data are available on the development of architecture and mechanical adaptation in juvenile trabecular bone. We studied the hypothesis that a time lag occurs between the adaptation of trabecular density and the adaptation of trabecular architecture during development. To investigate...
Although bone strength and modulus are known to be influenced by both volume fraction and mineral content (ash fraction), the relative influence of these two parameters remains unknown. Single-parameter power law functions are used widely to relate bone volume or ash fraction to bone strength and elastic modulus. In this study we evaluate the potential for predicting bone mechanical properties with...
Amylin and calcitonin gene-related peptide (CGRP) are homologous 37 amino acid peptides that are found in the circulation. Both peptides belong to the calcitonin family. Similar to calcitonin, amylin and CGRP inhibit osteoclast activity, although they are much less potent than calcitonin. Calcitonin is known to act on the latter stages of osteoclast development, inhibiting the fusion of committed...
Conventional hormone replacement therapy acts primarily by preserving bone, but cannot restore lost bone in women with established osteoporosis. Studies in rodents have shown that high doses of estrogens have anabolic skeletal effects, and recent observations in a group of women treated long term with high doses of estrogen indicated that similar effects occur in humans. This study examines the hypothesis...
This study tested the transduction efficiency of human bone marrow stromal cells (hBMSCs) with vesicular stomatitis virus (VSV)-pseudotyped retrovectors and their subsequent osteogenic differentiation in vitro. Two different retrovectors encoding β-galactosidase (β-gal) or enhanced green fluorescent protein (eGFP) as marker genes were examined for transduction of hBMSCs. hBMSCs were obtained from...
Parathyroid hormone (PTH) or synthetic N-terminal PTH fragments administered intermittently have been established as anabolic agents in animal and human bones. In the present study, the influence of a low calcium diet on the anabolic effect of human PTH(1-38) [hPTH(1-38)] was investigated. Forty-eight 10-week-old female Sprague-Dawley rats were randomly assigned to a diet with a low calcium content...
Ultrasound (US), a high-frequency acoustic energy traveling in the form of a mechanical wave, represents a potential site-specific intervention for osteoporosis. Bone is a dynamic tissue that remodels in response to applied mechanical stimuli. As a form of mechanical stimulation, US is anticipated to produce a similar remodeling response. This theory is supported by growing in vitro and in vivo evidence...
Neurotransmitter regulation of bone metabolism has been the subject of increasing interest and investigation. Because serotonin (5-HT) plays a role as a regulator of craniofacial morphogenesis, we investigated the expression and function of 5-HT receptors and the 5-HT transporter (5-HTT) in bone. Primary cultures of rat osteoblasts (rOB) and a variety of clonal osteoblastic cell lines, including ROS...
Fetal development and tumor progression both require a complex system of extracellular matrix (ECM) synthesis and breakdown, which is mediated by, for instance, the matrix metalloproteinases (MMPs). Human metalloelastase (MMP-12) is an MMP, the expression of which has so far been documented in macrophages associated with atherosclerosis, wound repair, and certain cancers. In this study we first examined...
Thyroid hormone plays a major role in the regulation of bone metabolism but the mechanism by which this is accomplished is not clear. Interactions of thyroid hormone with the growth hormone/insulin-like growth factors (IGFs) axis suggest an alternate pathway of action for triiodothyronine (T 3 ) on bone formation, besides direct effects. The present study investigates the influence of T ...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.