The aim of our study was to investigate the effects of ovariectomy on rat femur biomechanical parameters. Bone mineral density (BMD) and histological investigation were also evaluated. Fourteen female Sprague-Dawley rats (seven ovariectomized, seven control) were used. BMD was measured by dual-energy X-ray absorbsiometry. Bone biomechanical parameters were measured in femoral midshaft with tensile test using a biomaterial testing machine and maximum load, stiffness, energy absorption capacity (structural properties), ultimate stress, ultimate strain, and elastic modulus (material properties) were calculated. Diaphyseal cortical bone thickness was measured by using histological method. The ovariectomized (OVX) rat femur's BMD was 14% lower than control rats (p=0.006). Mean maximum load was 55% less than the control group's (p=0.0001). Stiffness was 72% less in OVX rats (p=0.05). Femurs of rats with OVX had 32% less absorbed energy than controls (p=0.09). From the stress-strain curve ultimate stress, ultimate strain and elastic modulus was calculated. Elastic modulus was 53% less than controls (p=0.05). Ultimate stress decreased 21% in OVX rats (p=0.097). Ultimate strain was 25% less than controls in OVX rats. Cortical thickness was significantly decreased in OVX rats than in controls (p<0.05). In conclusion, femur biomechanical parameters are decreased in osteoporosis.
Although the association of rheumatoid arthritis (RA) with HLA-DRB1 (shared epitope) is well demonstrated in many ethnic populations, the role of other RA-associated risk loci is not clarified. In this study, the functional single nucleotide polymorphism (SNP) of PTPN22 gene was investigated in Turkey. 167 patients with RA and 177 healthy controls are genotyped by polymerase chain reaction (PCR)-RFLP for the SNP (rs2476601, A/G) of PTPN22 gene. Polymorphic region was amplified by PCR and digested with Xcm I enzyme. Heterozygous genotype (AG) was present in 5.1% (9/177) of the controls and in 6.6% (11/167) of RA group (p = 0.55, OR 1.3, 95% CI 0.53–3.26). There was also no association between any clinical feature, RF positivity and presence of this SNP. In conclusion, the distribution of PTPN22 polymorphism did not reveal any association with RA in Turkey.
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