The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
J Moniuszkojakoniuk - One of the best experts on this subject based on the ideXlab platform.
-
beneficial effect of zinc supplementation on biomechanical properties of femoral distal end and femoral Diaphysis of male rats chronically exposed to cadmium
Chemico-Biological Interactions, 2008Co-Authors: Malgorzata M Brzoska, Katarzyna Majewska, Malgorzata Galazynsidorczuk, Joanna Rogalska, Alicja Roszczenko, M Jurczuk, J MoniuszkojakoniukAbstract:Abstract The present study was aimed at estimate, based on the rat model of human moderate and relatively high chronic exposure to cadmium (Cd), whether zinc (Zn) supplementation may prevent Cd-induced weakening in the bone biomechanical properties. For this purpose, male Wistar rats were administered Cd (5 or 50 mg/l) or/and Zn (30 or 60 mg/l) in drinking water for 6 and 12 months. Bone mineral density (BMD) and biomechanical properties (yield load, ultimate load, post-yield load, displacement at yield and at ultimate, stiffness, work to fracture, yield stress, ultimate stress and Young modulus of elasticity) of the femoral distal end and femoral Diaphysis were examined. Biomechanical properties of the distal femur were estimated in a compression test, whereas those of the femoral Diaphysis—in a three-point bending test. Exposure to Cd, in a dose and duration dependent manner, decreased the BMD and weakened the biomechanical properties of the femur at its distal end and Diaphysis. Zn supplementation during Cd exposure partly, but importantly, prevented the weakening in the bone biomechanical properties. The favorable Zn influence seemed to result from an independent action of this bioelement and its interaction with Cd. However, Zn supply at the exposure to Cd had no statistically significant influence on the BMD at the distal end and Diaphysis of the femur. The results of the present paper suggest that Zn supplementation during exposure to Cd may have a protective influence on the bone tissue biomechanical properties, and in this way it can, at least partly, decrease the risk of bone fractures. The findings seem to indicate that enhanced dietary Zn intake may be beneficial for the skeleton in subjects chronically exposed to Cd.
-
mechanical properties of femoral Diaphysis and femoral neck of female rats chronically exposed to various levels of cadmium
Calcified Tissue International, 2005Co-Authors: Malgorzata M Brzoska, Katarzyna Majewska, J MoniuszkojakoniukAbstract:The effect of chronic exposure to cadmium (Cd) on the mechanical properties of femoral Diaphysis and femoral neck was investigated on a rat model of human exposure. Three-week-old female Wistar rats were exposed to Cd in drinking water at concentrations of 1, 5, 50, or 100 mg/L for 12 months. Biomechanical properties of the femoral Diaphysis were evaluated in a three-point bending test and those of the femoral neck in a bending test with vertical loading of the head. Bone mineral content (BMC) and bone mineral density (BMD) at the whole femur, and BMD at the Diaphysis and proximal femur (head and neck region) of the Cd-treated rats decreased in a dose-dependent manner, except for the diaphyseal BMD at a Cd concentration of 1 mg/L. Exposure to Cd concentrations of 1 and 5 mg/L had only little effect on the diaphyseal mechanical properties (decreased yield load with unchanged bending strength, stiffness, yield stress, ultimate stress, and Young modulus), whereas the bending strength and stiffness of the neck decreased and the yield load clearly tended to decline or declined. The effect of Cd at the two locations was more marked in the 50 and 100 mg/L groups, and changes in the bone geometry were observed in these animals. The results clearly revealed that chronic, even low-level, exposure to Cd results in demineralization and weakening of the femur. The femoral neck seems to be more vulnerable than the Diaphysis to failure from Cd. We conclude that environmental exposure to Cd may be an important risk factor for femoral neck fracture.
Malgorzata M Brzoska - One of the best experts on this subject based on the ideXlab platform.
-
beneficial effect of zinc supplementation on biomechanical properties of femoral distal end and femoral Diaphysis of male rats chronically exposed to cadmium
Chemico-Biological Interactions, 2008Co-Authors: Malgorzata M Brzoska, Katarzyna Majewska, Malgorzata Galazynsidorczuk, Joanna Rogalska, Alicja Roszczenko, M Jurczuk, J MoniuszkojakoniukAbstract:Abstract The present study was aimed at estimate, based on the rat model of human moderate and relatively high chronic exposure to cadmium (Cd), whether zinc (Zn) supplementation may prevent Cd-induced weakening in the bone biomechanical properties. For this purpose, male Wistar rats were administered Cd (5 or 50 mg/l) or/and Zn (30 or 60 mg/l) in drinking water for 6 and 12 months. Bone mineral density (BMD) and biomechanical properties (yield load, ultimate load, post-yield load, displacement at yield and at ultimate, stiffness, work to fracture, yield stress, ultimate stress and Young modulus of elasticity) of the femoral distal end and femoral Diaphysis were examined. Biomechanical properties of the distal femur were estimated in a compression test, whereas those of the femoral Diaphysis—in a three-point bending test. Exposure to Cd, in a dose and duration dependent manner, decreased the BMD and weakened the biomechanical properties of the femur at its distal end and Diaphysis. Zn supplementation during Cd exposure partly, but importantly, prevented the weakening in the bone biomechanical properties. The favorable Zn influence seemed to result from an independent action of this bioelement and its interaction with Cd. However, Zn supply at the exposure to Cd had no statistically significant influence on the BMD at the distal end and Diaphysis of the femur. The results of the present paper suggest that Zn supplementation during exposure to Cd may have a protective influence on the bone tissue biomechanical properties, and in this way it can, at least partly, decrease the risk of bone fractures. The findings seem to indicate that enhanced dietary Zn intake may be beneficial for the skeleton in subjects chronically exposed to Cd.
-
mechanical properties of femoral Diaphysis and femoral neck of female rats chronically exposed to various levels of cadmium
Calcified Tissue International, 2005Co-Authors: Malgorzata M Brzoska, Katarzyna Majewska, J MoniuszkojakoniukAbstract:The effect of chronic exposure to cadmium (Cd) on the mechanical properties of femoral Diaphysis and femoral neck was investigated on a rat model of human exposure. Three-week-old female Wistar rats were exposed to Cd in drinking water at concentrations of 1, 5, 50, or 100 mg/L for 12 months. Biomechanical properties of the femoral Diaphysis were evaluated in a three-point bending test and those of the femoral neck in a bending test with vertical loading of the head. Bone mineral content (BMC) and bone mineral density (BMD) at the whole femur, and BMD at the Diaphysis and proximal femur (head and neck region) of the Cd-treated rats decreased in a dose-dependent manner, except for the diaphyseal BMD at a Cd concentration of 1 mg/L. Exposure to Cd concentrations of 1 and 5 mg/L had only little effect on the diaphyseal mechanical properties (decreased yield load with unchanged bending strength, stiffness, yield stress, ultimate stress, and Young modulus), whereas the bending strength and stiffness of the neck decreased and the yield load clearly tended to decline or declined. The effect of Cd at the two locations was more marked in the 50 and 100 mg/L groups, and changes in the bone geometry were observed in these animals. The results clearly revealed that chronic, even low-level, exposure to Cd results in demineralization and weakening of the femur. The femoral neck seems to be more vulnerable than the Diaphysis to failure from Cd. We conclude that environmental exposure to Cd may be an important risk factor for femoral neck fracture.
Jian Wang - One of the best experts on this subject based on the ideXlab platform.
-
chondroblastoma in the long bone Diaphysis a report of two cases with literature review
Chinese Journal of Cancer, 2012Co-Authors: Jilong Yang, Wei Tian, Jian WangAbstract:To investigate the clinical characteristics of chondroblastoma with an emphasis on lesions located in the long bone Diaphysis, we reviewed the clinical data of 7 patients with histologically proven chondroblastoma treated in Tianjin Medical University Cancer Hospital and Fudan University Cancer Hospital between January 1995 and May 2009. There were two rare cases of chondroblastoma in the long bone Diaphysis. One patient with a lesion in the tibial Diaphysis underwent intralesional curettage and bone grafting, and the postoperative bone function was measured as excellent according to the Enneking scoring system. The patient was still alive upon follow-up at 60 months. The other patient with a lesion in the humeral Diaphysis underwent resection, and the postoperative bone function was excellent at 48 months, at which there was no evidence of recurrence or metastasis. Thus, except for the distinctive site of the long bone Diaphysis, which made diagnosis difficult, the patients' ages, symptoms, X-ray and CT images, treatment, and prognosis were in accordance with typical lesions in the epiphysis and metaphysis. The diagnosis of chondroblastoma in the long bone Diaphysis significantly depends on histopathologic characteristics.
Steven M Madey - One of the best experts on this subject based on the ideXlab platform.
-
far cortical locking can reduce stiffness of locked plating constructs while retaining construct strength
Journal of Bone and Joint Surgery American Volume, 2009Co-Authors: Michael Bottlang, Josef Doornink, Daniel C Fitzpatrick, Steven M MadeyAbstract:Background: Several strategies to reduce construct stiffness have been proposed to promote secondary bone healing following fracture fixation with locked bridge plating constructs. However, stiffness reduction is typically gained at the cost of construct strength. In the present study, we tested whether a novel strategy for stiffness reduction, termed far cortical locking, can significantly reduce the stiffness of a locked plating construct while retaining its strength. Methods: Locked plating constructs and far cortical locking constructs were tested in a diaphyseal bridge plating model of the non-osteoporotic femoral Diaphysis to determine construct stiffness in axial compression, torsion, and bending. Subsequently, constructs were dynamically loaded until failure in each loading mode to determine construct strength and failure modes. Finally, failure tests were repeated in a validated model of the osteoporotic femoral Diaphysis to determine construct strength and failure modes in a worst-case scenario of bridge plating in osteoporotic bone. Results: Compared with the locked plating constructs, the initial stiffness of far cortical locking constructs was 88% lower in axial compression (p < 0.001), 58% lower in torsion (p < 0.001), and 29% lower in bending (p < 0.001). Compared with the locked plating constructs, the strength of far cortical locking constructs was 7% lower (p = 0.005) and 16% lower (p < 0.001) under axial compression in the non-osteoporotic and osteoporotic Diaphysis, respectively. However, far cortical locking constructs were 54% stronger (p < 0.001) and 9% stronger (p = 0.04) under torsion and 21% stronger (p < 0.001) and 20% stronger (p = 0.02) under bending than locked plating constructs in the non-osteoporotic and osteoporotic Diaphysis, respectively. Within the initial stiffness range, far cortical locking constructs generated nearly parallel interfragmentary motion. Locked plating constructs generated significantly less motion at the near cortex adjacent to the plate than at the far cortex (p < 0.01). Conclusions: Far cortical locking significantly reduces the axial stiffness of a locked plating construct. This gain in flexibility causes only a modest reduction in axial strength and increased torsional and bending strength. Clinical Relevance: Far cortical locking may provide a novel bridge plating strategy to enhance interfragmentary motion for the promotion of secondary bone healing while retaining sufficient construct strength.
-
a nonlocking end screw can decrease fracture risk caused by locked plating in the osteoporotic Diaphysis
Journal of Bone and Joint Surgery American Volume, 2009Co-Authors: Michael Bottlang, Josef Doornink, Daniel C Fitzpatrick, Gregory D Byrd, Steven M MadeyAbstract:Background: Locking plates transmit load through fixed-angle locking screws instead of relying on plate-to-bone compression. Therefore, locking screws may induce higher stress at the screw-bone interface than that seen with conventional nonlocked plating. This study investigated whether locked plating in osteoporotic diaphyseal bone causes a greater periprosthetic fracture risk than conventional plating because of stress concentrations at the plate end. It further investigated the effect of replacing the locked end screw with a conventional screw on the strength of the fixation construct. Methods: Three different bridge-plate constructs were applied to a validated surrogate of the osteoporotic femoral Diaphysis. Constructs were tested dynamically to failure in bending, torsion, and axial loading to determine failure loads and failure modes. A locked plating construct was compared with a nonlocked conventional plating construct. Subsequently, the outermost locking screw in locked plating constructs was replaced with a conventional screw to reduce stress concentrations at the plate end. Results: Compared with the conventional plating construct, the locked plating construct was 22% weaker in bending (p = 0.013), comparably strong in torsion (p = 0.05), and 15% stronger in axial compression (p = 0.017). Substituting the locked end screw with a conventional screw increased the construct strength by 40% in bending (p = 0.001) but had no significant effect on construct strength under torsion (p = 0.22) and compressive loading (p = 0.53) compared with the locked plating construct. Under bending, all constructs failed by periprosthetic fracture. Conclusions: Under bending loads, the focused load transfer of locking plates through fixed-angle screws can increase the periprosthetic fracture risk in the osteoporotic Diaphysis compared with conventional plates. Replacing the outermost locking screw with a conventional screw reduced the stress concentration at the plate end and significantly increased the bending strength of the plating construct compared with an all-locked construct (p = 0.001). Clinical Relevance: For bridge-plating in the osteoporotic Diaphysis, the addition of a conventional end screw to a locked plating construct can enhance the bending strength of the fixation construct without compromising construct strength in torsion or axial compression.
-
relative stability of conventional and locked plating fixation in a model of the osteoporotic femoral Diaphysis
Clinical Biomechanics, 2009Co-Authors: Daniel C Fitzpatrick, Josef Doornink, Steven M Madey, Michael BottlangAbstract:Background: This study investigated the stiffness and strength of bridge plating with uni-cortical and bicortical locking plate constructs relative to a conventional, non-locked construct in the osteoporotic femoral Diaphysis. Methods: Four bridge plating configurations were applied to a validated model of the osteoporotic femoral Diaphysis. A non-locked conventional configuration served as baseline. Locked configurations included bi-cortical locked plating, uni-cortical locked plating and mix-mode locked plating, which combined uni and bi-cortical locking screws. For all configurations, an 11-hole plate was applied with 4.5-mm screws placed in the 1st, 3rd, and 5th plate hole. Five specimens of each configuration were dynamically loaded until failure in torsion, axial compression, and bending to determine construct stiffness, strength and failure modes. Findings: In torsion and bending, locked plating constructs provided a significantly lower stiffness and strength than the conventional construct. The uni-cortical locked construct was 69% weaker ( P< 0.001) in torsion than the conventional construct, but its torsional strength improved 73% ( P< 0.001) by adding one bi-cortical locked screw. In axial compression, construct stiffness varied by less than 10% between the four groups. However, the bi-cortical and mixed-mode locked constructs provided a significant increase in strength of 12% ( P= 0.001) and 11% ( P= 0.002), respectively, compared to the conventional construct. Interpretations: Locked plating in the osteoporotic Diaphysis can improve fixation strength under axial loading, but may reduce fixation strength in bending and torsion compared to conventional plating. Adding one bi-cortical locked screw to an otherwise uni-cortical construct is recommended to improve torsional strength.
F.j. Garcia Sanchez - One of the best experts on this subject based on the ideXlab platform.
-
Correlation between low-frequency electric conductivity and permittivity in the Diaphysis of bovine femoral bone
IEEE Transactions on Biomedical Engineering, 1992Co-Authors: G. De Mercato, F.j. Garcia SanchezAbstract:The relationship between the low-frequency electric properties in the axial, tangential, and radial directions along the Diaphysis of a femoral bovine bone is presented. It is shown that below 1 MHz the relative permittivity of the Diaphysis exhibits a significant positive correlation with respect to the low-frequency conductivity, as measured in any direction, and therefore it could be related to the amount of fluid contained in the channels that provide low-frequency electrical connectivity in the measurement direction. There is no significant correlation between permittivity, in either of the three measurement directions, and the total fluid volumetric fraction in the bone.
-
Variation of the electric properties along the Diaphysis of bovine femoral bone.
Medical & Biological Engineering & Computing, 1991Co-Authors: G. De Mercato, F.j. Garcia SanchezAbstract:A preliminary study is presented of the variability of the electric properties, in the axial, tangential and radial directions, as a function of position in the Diaphysis of a femoral bovine bone. The measurements were carried out at three frequencies: 100 Hz, 10 kHz and 1 MHz. It is shown that both the conductivity and the permittivity exhibit significant variations along the Diaphysis, and increase in magnitude towards the epiphyses. From this study, the variation of the electric properties cannot be clearly and directly ascribed to the longitudinal variability of the total volumetric fluid content of the bone. The results reflect the orthotropic nature of the electric properties, at any given location, and indicate a position-dependent tendency towards axis symmetry.
