Effect of polyalkyl polyphosphonates on bone development in young rats.
Explore the source record for details and available documents.
SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Prostaglandin (PG) E2 displays physiological and pharmacological action in various tissues including bone. It increases intracellular Ca, and stimulates or inhibits cAMP production through the PGE receptor subtypes EP1, EP2, and EP3, respectively. These receptor subtypes have been recently cloned. In the present study, we investigate the expression of these receptor subtypes in bone tissue. RT-PCR revealed that EP1, EP2, and EP3 were expressed in rat calvariae and that osteoblastic cells (MC3T3-E1) expressed EP1 and EP2. In situ hybridization analysis using cryosection of neonatal calvariae revealed that EP2 was expressed by osteoblasts and cells not in contact with bone, probably including preosteoblasts. EP2 expression was observed at an early stage in calvarial development, at 14 days prenatal. EP2 expression was also observed at day 3 in rat bone marrow cell culture in which bone-like mineralized nodules are formed at day 8. It has been established that PGE2 response accompanying cAMP production is one of the characteristics of osteoblasts. The present results indicate that this phenotype appears at an early stage of osteoblastic differentiation and bone development.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Progressive tissue expansion induces significant gross, histologic, and bony changes in skulls and long bones of neonatal miniature swine. These bony changes consist of erosion underlying tissue expanders, with bony lipping and bone deposition at the periphery of the expander. Cranial suture lines underneath expanders appear effaced and convoluted. Serial CT scans reveal decreased bone thickness and volume (p less than 0.02) but identical bone density (p = 0.60) beneath expanders. Increased bone volume and thickness occur at the periphery of expanders (p less than 0.02). Bone density (CT number) is unaffected by tissue expansion in both cranial and long bones. These findings have histomorphometric correlates: Osteoclastic bone resorption occurs underneath expanders with periosteal reaction at the periphery of expanders. Cranial sutures are similarly affected, but no cranial synostosis results. No changes to the inner table of the skull or stigmata of increased intracranial pressure were observed either in CT scans or in behavioral changes in long-term animals. The pathophysiology of bony changes is a remodeling effect, not one of simple pressure deformation. Increased bone resorption and complete inhibition of bone formation occur until the pressure is removed. Cranial bone is significantly more affected than long bone. After removal of the expanders, reparative bone remodeling begins within 5 days and nearly complete healing of the cranial defects occurs within 2 months (p less than 0.02). No plagiocephaly results despite early coronal suture changes. On the basis of this study, we conclude that tissue expansion causes significant but reversible effects, readily monitored by high-resolution CT scans, on neonatal and infant cranial and long bones.
Effects of cassava (Manihot esculenta Crantz)-borne organic cyanide and inorganic cyanide in the form of sodium cyanide on bone and muscle development were investigated in eighteen dogs of Nigerian breed. After 16 weeks of stabilization in the laboratory from the time of purchase when the dogs were fed on the same diet, they were randomly assigned to three experimental groups of six dogs each. The control group was fed on rice while the other two groups were fed on either cassava (gari) or rice plus cyanide. The three diets were made isoenergetic and isonitrogenous by varying the quantity of meat incorporated into them. The results obtained after 14 weeks of feeding the respective diets indicated that there was retardation of muscle development in the gari-fed dogs. This may have resulted from gluconeogenesis from muscle protein associated with suppression of production of insulin by the pancreas in this group. The results indicated also that the effects of inorganic dietary cyanides on muscle development were different. Both forms of dietary cyanides, however, had no adverse effect on bone development.
Changes in plasminogen activator activity were studied during the sequential developmental stages of matrix-induced cartilage, bone, and bone marrow development. The morphological transitions were correlated with biochemical parameters. Morphologic evidence of vascularization of calcified hypertrophic cartilage was accompanied by a concomitant rise in plasminogen activator activity. Thereafter, a steady decline during mineralization and deposition of new bone was observed. Maximal plasminogen activator activity occurs at approximately the same time as peak activity of alkaline and acid phosphatase. These results imply a role for plasminogen activator during angiogenesis, vascular invasion, and attendant bone differentiation.
Explore the source record for details and available documents.
The paper investigated the changes of rabbit's tooth and jaw tissues by vitamin-D poisoning experiment. The results showed the dentin, periodontium, jaw bone and long bone of rabbit were all changed. X-ray showed subperiosteum absorbation and periosteum reaction. The mineral content of the rabbit's epiphysis and long bone diaphysis in experiment group were lower than that of control group. The histopathological findings were irregular hyperplasia of dentin, arrange disturbance of periodontal fibers, absorbation of the alveolar bone and mal-ossification of long bones. The above changes were more significant during 30-45 days of rabbit poisoning, after 60 days of poisoning the above signs were gradually released.
Using nondegradative isolation procedures, we purified and characterized a glycoprotein from fetal calf bone that is rich in sialic acid. This bone sialoprotein (BSP) has an apparent Mr = 70,000-80,000 and stains with Alcian blue and Stains All on sodium dodecyl sulfate gels but does not stain with Coomassie blue without prior treatment with neuraminidase. This glycoprotein contains 50% protein, 12% sialic acid, 7% glucosamine, and 6% galactosamine. Fetal calf BSP is rich in glutamate (19%), aspartate (15.4%), and glycine (11.8%) but, in contrast to osteonectin and the bone proteoglycan, has relatively low amounts of leucine (4.3%). Antisera raised against fetal calf BSP localized the glycoprotein by indirect immunofluorescence to developing bone trabeculae with an overall tissue distribution identical with that of osteonectin. On competition enzyme-linked immunosorbent assay analysis, BSP was 11.5% (+/-2.4%, S.E.) of mineral-bound (guanidine-EDTA-soluble) calf bone protein. Immunoreplicas (Western blots) of calf bone extracts suggest that more than 95% of the antigenicity resided in the Mr = 70,000-80,000 region with the remaining cross-reactivity in Alcian blue positive, Mr = approximately 20,000 and approximately 30,000 bands. Brief treatment of the Mr = 70,000-80,000 species with trypsin produced lower molecular weight, Alcian blue-staining products of similar size. No BSP was detected in guanidine extracts of various soft or unmineralized connective tissues, but dentin contained small amounts (0.4%) of the protein. Rat and fetal human bone were also observed to contain a sialoprotein with similar properties and a certain degree of cross-reactivity with the bovine BSP.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Lameness in a group of 5- to 12-month-old calves was found to be clinically, radiographically, and pathologically associated with abnormal bone development of the distal growth plates of the metacarpus and metatarsus. Copper concentrations in serum and liver were low. Serum calcium, phosphorus, and alkaline phosphatase values were normal. In pasture forage samples, sulfate, zinc, and molybdenum concentrations were high, whereas copper, calcium, and phosphorus concentrations were normal. Red blood cell (RBC) counts and hemoglobin values were within normal limits. Radiographic findings included a widened zone of cartilage and lipping of the medial and lateral areas of the physeal plate. Histologic findings included focal widenings of the growth plate consisting of tongues of uncalcified cartilage.
Transgenic mice were generated expressing c-fos genes under the control of the human metallothionein promoter. Although high levels of c-fos messenger RNA were detectable in a variety of tissues, deregulated c-fos expression specifically interfered with normal bone development without inducing malignant tumours.