Papers by Keyword: Bone Mineral Density

Abstract: Bone tissue is a calcium deposit and supporting structure of the human body, it is exposed to several pathologies that modify its mineral content. To determine these changes, different diagnostic procedures are performed with techniques using invasive ionizing radiation, which are limited by the negative effects in the long term on human health. A methodology is explored that could be applicable in the diagnosis of pathologic variations in bone mineral density, using structural monitoring tools. The proposed technique estimates changes in bone conditions by applying impedance spectroscopy with a tooth-borne piezo-device. Bone-tooth samples were prepared to simulate a section of maxillary bone and subsequently treated with chemical agents, simulating pathologic decalcification. The piezo-device is inserted in the slot of an orthodontic bracket, previously bonded to the crown of the tooth, in order to transmit vibration to surrounding bone. The variations in bone micro-architecture were computed by image processing analyzed with samples prepared in transparent resin, allowing the measurement of morphometry before and after the induced changes in mineral content. Using vibrational bone response, impedance measurements allowed to observe the variations in bone mass as the samples were progressively decalcified. In the 5-50kHz spectrum, it was demonstrated the sensitivity of the electro-mechanical impedance during the bone alteration procedure since the electrical resistance signals of the piezo-device consistently changed in the frequency spectrum (5-50kHz). The piezo-device shows to be sensitive to the changes produced by the bone alterations, which were caused by the stiffness variations made in the sample during the decalcifying. These changes were statistically correlated to demonstrate that in a less invasive way, bone alterations could be monitored from the teeth. This result opens the door to search for a new way to diagnose bone density changes in real applications.

Abstract: Osteoporosis is a chronic, metabolic and systemic skeletal disease characterized by low bone mineral density (BMD) and micro-architectural deterioration, resulting in increased bone fragility and fracture risk. Changes in the mineral structure occur due to aging or because of progressive pathologic processes such as osteoporosis, as well as in both aging and effects of bone diseases.

Abstract: Radio Density of bones is measured in Hounsfield Units (HU) by a technique called as tomography, whereas the Bone Mineral Density (BMD) is measured by Dual-energy X-Ray Absorptiometry (DXA) scan. We aimed at finding correlation between BMD and HU of human bones for their strength evaluation.

Abstract: Compound pearl protein polypeptide (CPPP) was investigated by MTT method as well as detecting alkaline phosphatase (ALP) and mineralized nodes in osteoblasts from SD rats. In vivo the rat models of osteoporosis were induced by ovariectomy and treated with three doses of CPPP (5.0mg.kg^-1.d^-1, 20.0mg.kg^-1.d^-1, and 80.0mg.kg^-1.d^-1). The serum levels of estradiol (E2), osteocalcin (BGP), transforming growth factors (TGF-β1) and ALK, together with the bone mineral density (BMD) and the contents of calcium (Ca) and phosphorus (P) in 24h urine, were detected. The results show that CPPP can enhance cell proliferation, ALK activity and the number of mineralized nodes in rats osteoblasts. CPPP significantly increase the serum level of E₂, TGF-β₁, and BMD, and decrease the serum level of ALP, BGP and the contents of Ca, P in 24h urine. So, CPPP can increase bone density, and thus it is conductive to osteoporosis prevention and treatment of the elderly.

Abstract: Objectives: Use quantitative ultrasound technology to determine the bone density of children and adolescents, understand the status and variation of ultrasonic bone density in children and adolescents.Methods: By stratified random cluster sampling, selected 3629 studenes in five schools in Tangshan and measured height and weight,and determined the right foot heel bone density using ultrasonic bone density analyzer.Results: It showed that the average of ultrasonic bone mineral density were 1535.4±20.6(m/s), decreased at the age of 6 to 9 years old and then increased with the age growth; at the age of 9 was the lowest, the SOS value of ultrasonic bone mineral density rebounded slightly from 10 to 13-year-old, after 13-year-old the SOS value increased with the age growth, the highest was at the age of 19. Ultrasonic bone density was associated with height,weight and body mass index.Conclusions: The development of the bone is a dynamic continuous evolutionary process, bone mineral density presented different rules for the different of age, gender, physical development status.

Abstract: Simvastatin, as one of the HMG-CoA reductase inhibitors for lowering lipids, has been demonstrated its potential benefit in bone formation, which was, however, conflicting and inconclusive in vivo studies. Thus, we performed this study to assess the in vivo effects of simvastatin on bone formation. Six-week old rats were administered with simvastatin (20 mg/kg/d) or vehicle for 6 or 9 weeks. All animals were sacrificed one day after the final administration. The left femora were removed for the measurement of bone histomorphometry and bone mineral density (BMD).Compared to the control groups, on both 6th week and 9th week, bone mineral density and bone histomorphometry detected no significant differences in bone mass and microarchitecture in simvastatin treatment group, as well as bone formatin/resorption parameters. These results indicate that simvastatin had no positive effect or impact on bone in rats administered with high dose simvastatin (20 mg/kg/d) for 6 or 9 weeks.

Abstract: Ovariectomized rats were fed a diet containing minerals at high concentrations, such as Ca, P, and F (high-mineral diet), and changes in the femoral diaphysis were investigated after 24 weeks. The femur was mainly red and partially orange on the color scale of the 3D-map in Groups A and B, showing a high BMD. The region adjacent to the marrow cavity was yellow, showing a lower BMD than that in the outer region of the femur. In Group C, the red area was small in the outer region and the inner region was mainly yellow and green on the color scale. The inner region adjacent to the marrow cavity showed a view of unevenly resorbed bone, and the BMD was lower than those in Groups A and B. Incorporation of F into the body influences the apatite crystal structure and crystal growth, which subsequently influences adsorption of F to crystals and structural changes. Therefore, it is important to ingest F at the optimum concentration.

Abstract: A biodegradable drug delivery system was established using an apatite cement containing simvastatin. The in-vitro drug release from apatite with lower-crystallinity was investigated under simulated osteoblast and osteoclast conditions (SOB and SOC). Apatite cement containing 6% simvastatin had lower crystallinity as the same as natural bone. In-vitro drug release tests were performed under SOB in simulated body fluid (pH 7.8), and then under SOC in acetate buffer (pH4.5) at 37.0｡C, and the process repeated twice. The device had lower drug release rates under SOB, but significantly higher rates under SOC. The simvastatin release rate was 15 times higher under SOC than SOB. The device showed dissolution medium responsive drug release. After implantation of the APC containing simvastatin in osteoporosis rats, the bone mineral density was evaluated by the X-ray computed tomography. The result indicated that the bone mineral density of APC implanted rat was significantly higher than that of control diseased.

Abstract: We have developed a new Ti alloy, Ti-15%Zr-4%Nb-4%Ta alloy (Ti-15-4-4) that showed higher biological safety and mechanical properties than the currently used Ti-6%Al-4%V alloy. The purpose of this study is to determine the biological performance of the new alloy. Ti-15-4-4 implants (machined or blasted) were placed in surgically created defects in rabbit femurs. The rabbits were sacrificed after 4, 8, 16, 24 and 48 weeks. Bone mineral density (BMD) and area of newly formed bone around the implants were measured using micro-CT. Results showed that the Ti-15-4-4 alloy is biocompatible and forms new bone around the Ti-15-4-4 implant, regardless of the surface treatment. The BMD and area of newly formed bone around the blasted implant surfaces were significantly greater than those around the machined surfaces. These results indicate that the new Ti-15-4-4 alloy has a potential for use as implants and has the advantage of improved mechanical properties described in earlier studies.

Abstract: Bone microstructure and its functions are maintained by the activity of bone cells such as osteoclast for bone resorption and osteoblast for bone formation. In this study, we examined the role of osteoclast on the formation of the preferential orientation of biological apatite (BAp) as a bone quality parameter using OPG-KO and op/op mouse models in which the expression of osteoclast increases for osteoporosis and decreases for osteopetrosis. The orientation degree of the BAp c-axis was analyzed by a microbeam X-ray diffraction system. We found more decrease in the preferential alignment of the BAp c-axis along the longitudinal direction of bone in the femoral bones of both OPG-KO and op/op mice at 12 weeks compared with normal control mice. We concluded that changes in the amount and activity of osteoclast affect BAp alignment, resulting in the degradation of bone microstructure in osteoporosis and osteopetrosis.