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At least 325 records · Page 18Linked to original sources
PubMed1988

Concurrent assays of circulating bone Gla-protein and bone alkaline phosphatase: effects of sex, age, and metabolic bone disease.

We measured the serum concentrations of 2 biochemical markers of bone formation, bone Gla-protein (BGP) and bone alkaline phosphatase (BAP), in 164 normal subjects and 164 patients with metabolic bone disorders. The data were reported as Z scores (deviation in SDs from the sex-specific age regression in normal subjects). Both serum BGP and BAP distinguished abnormalities well (mean Z scores for BGP and BAP, respectively) and gave concordant results in patients with hypoparathyroidism (-1.7, -1.4), hyperthyroidism (+1.1, +1.8), primary hyperparathyroidism (+3.6, +2.5), acromegaly (+1.2, +2.8), and postmenopausal osteoporosis (+0.4, +1.9). The 2 markers gave discordant results, however, in patients with glucocorticoid excess (-2.4, +0.9), Paget's disease (+1.8, +41.8), chronic renal failure (+16.3, +0.4), and osteolytic metastases (-1.4, +5.9). These discrepancies may have occurred because serum BGP and BAP concentrations reflect different aspects of osteoblast function or because there are differences in their clearance from the circulation. Consequently, more information is derived about the level of bone formation across the wide range of metabolic bone disorders when both biochemical markers are assayed.

Adult↗
PubMed2004

Value of bone scintigraphy for detection and ageing of vertebral fractures in patients with severe osteoporosis and correlation between bone scintigraphy and mineral bone density.

Osteoporosis is the most common of the metabolic bone diseases, and is an important cause of morbidity in the elderly. Bone scintigraphy is used to detect skeletal lesions at the earliest possible time, to monitor the course of the skeletal discase and to evaluate the metabolic activity of skeletal lesions. The aim of this study was to determine, by using the bone scan age of vertebral fractures in patients with severe osteoporosis, and make correlation between bone scintigraphy and mineral bone density. Material and methods 30 female patients were studied with bone scintigraphy after BMD.BMD was measurred with DEXA Hologic QDR 4500 Elite System. Correlation between T-score and uptake of radiofarmaceutical (Tc-99mMDP) was 0.849, and it was high. Intensity of uptake of Tc-99m MDP scintigraphy is an accurate method for the detection and ageing of fractures in osteoporotic patients.

Absorptiometry, Photon↗
PubMed2006

[Poor bone quality in diabetes: detrimental collagen cross-link pattern reduces bone strength without change in bone mineral density].

Although type 2 diabetes is often characterized by normal or high bone mineral density (BMD), diabetes is associated with increased risk of fracture. This paradoxical phenomenon in type 2 diabetes may be explained by poorer "bone quality" by detrimental collagen cross-links in bone. Recently, we showed that the alteration of enzymatic and nonenzymatic crosslinking in bone could be important for explaining the variation of fracture susceptibility in diabetes (Osteoporos Int, 2006. Epub ahead of print). In this review, we describe that low turnover bone, hyperglycemia, mildly hyperhomocysteinemia, and vitamin B(6) insufficiency are crucial determinants of detrimental crosslinking of bone collagen in diabetes.

Animals↗
PubMed2002

A new technique for cranial bone osteofixation: use of bioabsorbable tacks and plates to fix parietal bone split grafts used for reconstruction of a posttraumatic frontal bone defect.

Recent advances in bioabsorbable devices have introduced tacks that do not require tapping. This may help to reduce operative time and, consequently, costs. The goal of this study was to demonstrate the feasibility of a new method of cranial bone osteofixation using novel bioabsorbable tacks and plates instead of screws. A 36-year-old man presented for elective cranioplasty to reconstruct a large frontal cranial bone defect that followed a decompression operation performed because of a head injury sustained 6 months previously. Cranioplasty was performed using split parietal bone grafts to reconstruct the defect. Bone grafts were fixed together and to the skull using self-reinforced (SR) poly(L/DL)lactide [SR-poly(L/DL)lactide] (70/30) (Biosorb FX) plates (n = 10) and tacks (n = 98). The plates were 0.6 mm thick, 102 mm long, and 12 mm wide. The tacks had a maximum thread diameter of 2 mm and a length of 6 mm. The tacks used did not require any tapping procedure, and they were applied using a special applicator gun. Stable and secure fixation was obtained during surgery. The postoperative period was uneventful, except for delayed epithelialization of a small area (1 x 0.5 cm) over the frontal skin that healed later. One year after surgery, the cosmetic result was excellent, and no complications were detected. Stabilization of large cranial bone pieces can be achieved using bioabsorbable SR-poly(L/DL)lactide plates and tacks, with excellent cosmetic results. The method is thought to be reliable and may help to reduce operative time.

Absorbable Implants↗
PubMed2006

Association of bone metabolism related genes polymorphisms with the effect of raloxifene hydrochloride on bone mineral density and bone turnover markers in postmenopausal women with osteoporosis.

OBJECTIVE: To investigate the association of bone metabolism related genes polymorphisms with the effect of raloxifene hydrochloride(RLX) on bone mineral density (BMD) and bone turnover markers in postmenopausal women with osteoporosis. METHODS: A total of 68 unrelated postmenopausal women with osteoporosis of Han ethnicity aged 47-74 years were randomly divided into 2 groups of 34 women: RLX group (60 mg were given daily for 12 months) and placebo group. BMD and bone turnover markers were measured at baseline, 6 and 12 months after treatment. The polymorphisms of Xba I and Pvu II sites in estrogen receptor 1 gene(ESR1), Ras I site in ESR2 gene, and start codon (Fok I) and CDX2 binding sites in vitamin D receptor gene (VDR) were analyzed. RESULTS: A total of 58 patients completed 12 months of study period. By the end of study, the increased percentage of BMD in lumbar spine 2-4 (L2-4), total hip, and trochanter were found significantly different between RLX group and placebo group(P<0.05), and the decreased percentage of C-telopeptide and osteocalcin were significantly different between the two groups (P<0.01). The BMD of total hip and trochanter of women with FF genotypes of VDR Fok I site were decreased by 1.98%+/-4.86% and 2.26%+/-4.73% respectively in the RLX group, but those of women with Ff/ff genotypes were increased by 2.52%+/-2.75% and 2.74 %+/-2.97%, respectively(P<0.05). Moreover, the total hip BMD of women with PP/Pp genotypes of ESR1 Pvu II site was increased by 2.12%+/-2.78%, and of women with pp genotype it was decreased by 1.34%+/-3.73%(P<0.05). However, no significant association was observed of the polymorphisms of five sites with the changes of BMD and bone turnover markers in the placebo group. CONCLUSION: The effect of RLX on BMD in postmenopausal women with osteoporosis is regulated by the polymorphisms of Fok I of VDR gene and Pvu II of ESR1 gene. The study is valuable to select this drug according to genotype of patients in clinical.

Aged↗
PubMed2006

Engineering of bone using bone marrow stromal cells and a silicon-stabilized tricalcium phosphate bioceramic: evidence for a coupling between bone formation and scaffold resorption.

Resorbable porous ceramic constructs, based on silicon-stabilized tricalcium phosphate, were implanted in critical-size defects of sheep tibias, either alone or after seeding with bone marrow stromal cells (BMSC). Only BMSC-loaded ceramics displayed a progressive scaffold resorption, coincident with new bone deposition. To investigate the coupled mechanisms of bone formation and scaffold resorption, X-ray computed microtomography (muCT) with synchrotron radiation was performed on BMSC-seeded ceramic cubes. These were analyzed before and after implantation in immunodeficient mice for 2 or 6 months. With increasing implantation time, scaffold thickness significantly decreased while bone thickness increased. The muCT data evidenced that all scaffolds showed a uniform density distribution before implantation. Areas of different segregated densities were instead observed, in the same scaffolds, once seeded with cells and implanted in vivo. A detailed muX-ray diffraction analysis revealed that only in the contact areas between deposited bone and scaffold, the TCP component of the biomaterial decreased much faster than the HA component. This event did not occur at areas away from the bone surface, highlighting coupling and cell-dependency of the resorption and matrix deposition mechanisms. Moreover, in scaffolds implanted without cells, both the ceramic density and the TCP:HA ratio remained unchanged with respect to the pre-implantation analysis.

Animals↗
PubMed2003

In vitro bone formation using muscle-derived cells: a new paradigm for bone tissue engineering using polymer-bone morphogenetic protein matrices.

Over 800,000 bone grafting procedures are performed in the United States annually, creating a demand for viable alternatives to autogenous bone, the grafting standard in osseous repair. The objective of this study was to examine the efficacy of a BMP-polymer matrix in inducing the expression of the osteoblastic phenotype and in vitro bone formation by muscle-derived cells. Specifically, we evaluated the ability of bone morphogenetic protein-7 (BMP-7), delivered from a poly(lactide-co-glycolide) (PLAGA) matrix, to induce the differentiation of cells derived from rabbit skeletal muscle into osteoblast-like cells and subsequently form mineralized tissue. Results confirmed that muscle-derived cells attached and proliferated on the PLAGA substrates. BMP-7 released from PLAGA induced the muscle-derived cells to increase bone marker expression and form mineralized cultures. These results demonstrate the efficacy of a BMP-polymer matrix in inducing the expression of the osteoblastic phenotype by muscle-derived cells and present a new paradigm for bone tissue engineering.

Absorbable Implants↗
PubMed1989

Absorption of onlay bone grafts in immature rabbits: membranous versus enchondral bone and bone struts versus paste.

The absorption of onlay membranous and enchondral bone graft struts and paste was studied in immature New Zealand rabbits using a volume-displacement technique to determine the volume change in the grafts 8 weeks and 21 weeks after grafting. Membranous and enchondral bone paste does not survive as an onlay graft. Both enchondral and membranous bone graft struts undergo significant resorption (78% decreased volume in the enchondral grafts and 50% in the membranous bone grafts). These data support the clinical experience that both types of onlay bone grafts lose significant volume, and are in relative contradistinction to prior animal studies comparing membranous and enchondral onlay bone grafts.

Animals↗
PubMed2006

Controlling bone morphogenetic protein diffusion and bone morphogenetic protein-stimulated bone growth using fibrin glue.

STUDY DESIGN: An in vitro and in vivo study. OBJECTIVE: To evaluate the ability of fibrin glue to limit diffusion of recombinant human bone morphogenetic protein (rhBMP)-2 and its ability to protect spinal nerves from rhBMP-2 stimulated bone growth. SUMMARY OF BACKGROUND DATA: Studies have shown bone morphogenetic protein (rhBMP-2) stimulated bone growth can encroach on the spinal canal and nerves, causing neural compression. More recently, rhBMP-2 use in the cervical spine has been associated with life-threatening swelling. Fibrin glue has been used as a biologic carrier but has not been evaluated for its ability to limit rhBMP-2. METHODS: In phase 1 of the study, rhBMP-2 soaked absorbable collagen sponges (ACS) were encapsulated in fibrin glue and immediately incubated in physiologic lactated ringers solution at 38 degrees C. Samples of solution were tested for rhBMP-2 concentration. In phase 2 of the study, rats were surgically treated with laminectomy and placement of rhBMP-2/ACS versus laminectomy and placement of fibrin glue before placement of rhBMP-2/ACS. After 8 weeks, animals were euthanized and imaged using micro-computerized tomography. RESULTS: The diffusion study showed a significant limitation in rhBMP-2 diffusion when encapsulated in fibrin glue. The laminectomy study revealed blockage of bone formation by fibrin glue and protection of the spinal canal. CONCLUSIONS: Fibrin glue can limit the diffusion of rhBMP-2, and, thus, it can be used to help protect the spinal canal and nerve roots from rhBMP-2 stimulated bone growth.

Animals↗
PubMed1999

Influence of exercise on bone mineral density of immature cortical and trabecular bone of the equine metacarpus and proximal sesamoid bone.

Bone mineral density (BMD) and cross-sectional area (CSA), measured using peripheral quantitative computed tomography, were determined in the left third metacarpal bone (MCIII) and left medial proximal sesamoid bone (psb) in 3 differently exercised groups of foals. Group(box) (n = 14) was confined to a box stall from birth to age 5 months, Group(training) (n = 14) was kept in similar box stalls but additionally given a daily exercise programme consisting of an increasing number of gallop sprints and Group(pasture) (n = 15) remained at pasture. At 5 months of age, 8 foals from each group were randomly selected and subjected to euthanasia, the remaining 19 foals were given an identical light exercise regimen for an additional 6 months and were killed at age 11 months. In MCIII CSA increased with age and was also significantly (P<0.05) larger in Group(pasture) compared to Group(box) at age 5 months. At 11 months this difference had disappeared. In the dorsal cortex, BMD was significantly (P<0.05) higher in Group(box) than in both other groups. At age 11 months all significant differences had disappeared. In the psb, CSA increased with age, but there were no differences between the exercise groups. At the apical level, trabecular BMD was higher in Group(training) than in Group(box) and Group(pasture) (P<0.001 and P<0.01, respectively). At 11 months, trabecular BMD in the foals that had belonged to Group(training) was less than in the foals that had belonged to Group(box) (P<0.05). It is concluded that box-rest during the first months of life results in a retardation of normal development which is compensated for when the restriction on exercise is lifted. Exercise during the first months of life induces an increase in CSA in the third metacarpal bone. In the psb exercise increases BMD, principally in trabecular bone. There is an indication that the specific training regimen used in this study led to an overstimulation of the bone resulting in less active mineral deposition in the longer term.

Animals↗
PubMed1999

Intermittent administration of human parathyroid Hormone(1-34) prevents immobilization-related bone loss by regulating bone marrow capacity for bone cells in ddY mice.

ddY mice, 6 weeks of age, were neurectomized (Nx) in the right hindlimbs and sham-operated (Sham) in the left limbs for evaluation of the effects of intermittent injections of human parathyroid hormone (hPTH) on trabecular bone turnover and bone marrow cell development in unloaded and loaded limbs. Mice were given subcutaneous injections of hPTH(1-34) five times a week at a dose of 0 (vehicle), 4 (low dose), or 40 (high dose) microg/kg of body weight for 2, 4, or 6 weeks. Histomorphometric analyses of the trabecular bone of the proximal tibiae revealed that high-dose hPTH injections preserved the trabecular bone volume of the Nx limbs, which was reduced after neurectomy, at the same level as that of the contralateral Sham limbs. The mineral apposition rate in the Nx limbs was elevated to values above even that of the Sham limbs by high-dose hPTH injections. The bone formation rate reduced by neurectomy was maintained at the Sham level by low- and high-dose hPTH injections. The neurectomy-induced increase in osteoclast number was suppressed by high-dose hPTH injections. In the bone marrow cells, the numbers of nonadherent and adherent cells per tibia obtained from the Nx and Sham limbs did not change. The hPTH injections decreased the numbers of nonadherent cells and increased those of adherent cells in both the Nx and the Sham limbs, but the effects were less marked in the Nx than in the Sham limbs even at high-dose injections. The formation of osteogenic nodules in the marrow cultures obtained from the Nx limbs was decreased after surgery and was maintained at the level of the Sham limbs by high-dose hPTH injections. The number of osteoclast-like multinucleated cells was reduced in the Sham limbs by high-dose hPTH injections. The value was increased at 2 weeks after neurectomy, but it was maintained at the Sham level by high-dose hPTH injections through the experimental period. The numbers of colony forming units-fibroblastic, which were reduced by neurectomy, and those of colony forming units for granulocytes and macrophages were not altered by hPTH injections. These results demonstrate that intermittent high-dose hPTH administration in the Nx limbs as well as in the contralateral Sham limbs has similar anabolic effects, stimulating osteoblast cell lineage and suppressing osteoclast cell lineage. The anabolic effects at 4 microg were reduced, but the effects at 40 microg seemed to be less affected by unloading due to sciatic neurectomy.

Animals↗
PubMed2002

Dietary essential amino acid supplements increase bone strength by influencing bone mass and bone microarchitecture in ovariectomized adult rats fed an isocaloric low-protein diet.

This study was designed to investigate whether the administration of dietary essential amino acid supplements in adult rats made osteoporotic by estrogen deficiency and reduced protein intake could reverse the deleterious effects caused by these maneuvers. This animal model was selected to mimic the situation observed in elderly women in whom estrogen deficiency and/or low-protein intake (but also calcium and vitamin D deficiency) are known to contribute to the pathogenesis of osteoporosis. Six-month-old rats were ovariectomized (OVX) and fed an isocaloric 2.5% casein diet for 10 weeks or sham-operated (SHAM) and fed an isocaloric 15% casein diet. The animals fed the 2.5% casein diet were given isocaloric supplements of essential amino acids in similar relative proportion to that of casein at doses of 2.5% or 5% of total diet for an additional 16 weeks. Vertebrae, femur, and tibia bone mineral density (BMD); ultimate strength; and microtomographic histomorphometry were evaluated before and after dietary essential amino acid supplements. Essential amino acid supplements increased vertebrae, femur, and tibia bone strength in OVX rats fed a low-protein diet. The mechanical changes induced by this dietary isocaloric supplement were associated with the prevention of a further BMD decrease or even with some increases and changes in microarchitecture such as from a rod to a plate trabecular spacial configuration and increased cortical thickness. Higher insulin-like growth factor (IGF) I levels, as well as greater bone formation and reduced bone resorption as assessed by biochemical markers of bone remodeling, were found in rats receiving essential amino acid supplements. In conclusion, dietary essential amino acid supplements increased bone strength through modifications of BMD, trabecular architecture, and cortical thickness possibly by an IGF-I-mediated process.

Amino Acids, Essential↗
PubMed1990

[Standardized bone model for incorporation of bone, bone ceramics or other materials into the implant bed].

To investigate the regeneration of human bone in a good and firm layer, a new model is introduced. It has been developed by us because of therapeutical necessity, but then is continued in the course of further investigations independent from further therapeutical procedure. We use the iliac crest as a bony layer for implants that are the object of research. For the therapy in cases of delayed bone healing, pseudarthrosis, bony defect or corrective osteotomy, the cancellous bone is removed. The empty iliac crest is then filled up with material we intend to investigate. On the occasion of further operations that became necessary because of the underlying bone disease, we had an opportunity to obtain sample of bone and material by hole-drilling through the iliac crest. The bony cylinder can be examined by histological technique. We used this procedure on 105 patients up to now. There were no specific complications caused by this technique at the iliac crest. 37 biopsies could be taken and will now be examined. In future it may be possible to incorporate new bone in this layer for a further therapy and to fill up the lost donor sites.

Bone Regeneration↗
PubMed1990

Elevation of the petrous bone caused by hyperplasia of the occipital bone presenting as hemifacial spasm: diagnostic values of magnetic resonance imaging and three-dimensional computed tomographic images in a bone anomaly.

A case of elevation of the petrous bone due to hyperplasia of the occipital bone presenting as hemifacial spasm is reported. A 44-year-old man sought treatment for twitching of the buccal muscles on the right side that progressed rapidly in severity within 2 weeks of the onset. The anatomical details of the petrous and occipital bones were delineated clearly by computed tomographic scans of a bone window level. Details of the brain stem were shown by magnetic resonance images. The bone anomaly was displayed more realistically by three-dimensional computed tomographic reconstructions. The faithful representation of structures with these radiological studies should be mandatory, to prepare the surgical planning of such a complicated bone anomaly.

Adult↗
PubMed1987

Growth potential in onlay bone grafts: a comparison of vascularized and free calvarial bone and suture bone grafts.

Vascularized bone grafts are characterized by a viable cell population with osteogenic potential. These features suggest that continued growth can be anticipated following vascularized membranous bone transfer in a growing craniofacial skeleton. The present paper compares the potential for appositional bone growth in vascularized and free calvarial onlay bone grafts. In seven 8-week-old beagles, growth was assessed by direct caliper measurements of graft dimensions intraoperatively and 16 weeks postoperatively. Vascularized grafts demonstrated a 50 to 60 percent increase in size in all dimensions compared to 10 to 20 percent growth in free grafts (p less than 0.01). Microradiography revealed preservation of calvarial bony architecture and minimal resorption in vascularized grafts, while triple-fluorochrome labeling confirmed subperiosteal appositional bone formation. Free grafts were characterized by significant resorption and a delay in subperiosteal bone formation.

Animals↗