Different muscle strategy during head/knee level of functional reaching-transporting task to decrease falling probability in postmenopausal women with osteoporosis.

BACKGROUND: The reaching-transporting task as an essential daily activity impacts balance control and falling in older women. This study investigated the different muscle strategies during the head/knee level of the functional reaching-transporting task in postmenopausal women with osteoporosis. METHODS: 24 postmenopausal volunteers were classified into two groups based on the lumbar T-score: osteoporosis (≤ -2.5, n = 12) and non-osteoporosis (> -1, n = 12). Using a custom-designed device, participants randomly performed 12 reaching-transporting tasks at the head and knee levels. Electromyography signals were collected while reaching and transporting phases with a wireless system. The peak of the root means square (PRMS) and time to PRMS (TPRMS) were measured. In addition, the isometric muscle strength and the fear of falling were assessed. RESULTS: The isometric muscle strength in the osteoporotic group was significantly lower than in the non-osteoporotic group (P < 0.05), except for vastus lateralis (VL). The PRMS of VL, (P = 0.010) during the reaching phase and VL (P = 0.002) and gastrocnemius lateralis (GL) (P < 0.001) during transporting phase was greater than the non-osteoporotic group. The PRMS value of the muscles was greater for reaching-transporting at the knee level than the head level; this increase was significant just for VL and biceps femoris during the transporting phase (P = 0.036 and P = 0.004, respectively). CONCLUSION: Osteoporotic women have more muscle activities during the reaching-transporting task, especially at the knee level, compared to the head level. Their muscle weakness may lead to insufficient stability during the task and cause disturbance and falling, which requires further investigation.

Characterization, mechanical properties and corrosion resistance of biocompatible Zn-HA/TiO2 nanocomposite coatings.

Biocompatible Zinc-hydroxyapatite-titania and Zinc-hydroxyapatite nanocomposite coatings have been prepared by electrodeposition on NiTi shape memory alloy. Structures of coatings were characterized using X-ray diffraction (XRD). It was found that addition of TiO2 particles cause to reduction of crystallite size of coating. Scanning Electronic Microscope (SEM) observation showed that the Zn-HA/TiO2 coating consists of plate-like regions which can express that this plate-like structure can facilitate bone growth. X-ray photoelectron microscope (XPS) was performed to investigation of chemical state of composite coating and showed that Zinc matrix was bonded to oxygen. high-resolution transmission electron microscope (HRTEM) result illustrated the crystalline structure of nanocomposite coating. Mechanical behavior of coating was evaluated using microhardness and ball on disk wear test. The TiO2 incorporated composite coatings exhibited the better hardness and anti-wear performance than the Zn-HA coatings. Polarization measurements have been used to evaluate the electrochemical coatings performance. The Zn-HA/TiO2 composite coatings showed the highest corrosion resistance compared with Zn-HA and bare NiTi.

Hyperhomocysteinemia and assessment of its associated factors in renal transplant recipients: a single-center study in northern Iran.

INTRODUCTION: Hyperhomocysteinemia (hyperHcy) is an important risk factor for atherosclerosis, which is currently a major cause of death in renal transplant patients (RTRs). The aim of this study was to determine the associated factors of hyperHcy in RTRs in northern Iran. METHODS: In 148 stable RTRs, total serum homocysteine (tHcy) level, folate, serum albumin and creatinine, creatinine clearance, lipid status, body mass index (BMI), and blood cyclosporine levels (C0 and C2) were determined. The mean doses of cyclosporine A (mg/kg/day) were recorded. RESULTS: In this analytic cross-sectional study the prevalence of hyperHcy was 70.3%. Hyperhomocysteinemia was defined as total serum homocysteine of 12 µmol/L or greater. The comparison of the group of 44 patients with tHcy level less than 12 and the group of 104 patients with tHcy level of 12 µmol/L or greater revealed that those subjects with hyperHcy were mostly younger, male, with lower BMI, history of glomerulonephritis, higher serum level of uric acid, and blood cyclosporine trough level (C0) and used higher doses of cyclosporine A. Significant correlation was found between tHcy level and recipients age, serum creatinine, BUN, folate concentrations, and creatinine clearance. However, multivariate analysis indicated that serum folate (P=0.01), vitamin B12 (P=0.05), creatinine (P=0.03), and BUN (P=0.05), and blood cyclosporine trough level (C0, P=0.005) were independently associated with tHcy levels. CONCLUSION: HyperHcy persists after successful kidney transplantation in the majority of RTRs. Serum creatinine, BUN, folate and vitamin B12, and blood cyclosporine trough level (C0) are independently associated with tHcy levels.