Search results for "Mineral"
showing 10 items of 2711 documents
Estrogen metabolism modulates bone density in men.
2007
Estrogen is a critical hormone for bone homeostasis in men, but no information is available on the role of estrogen metabolism among men. The aim of this study was to evaluate the effect of estrogen hydroxylation on male bone mineral density (BMD). Participants consisted of 61 healthy Caucasian males (mean age 66.6 +/- 1.0 years). Urinary estrogen metabolites were measured by enzyme-linked immunosorbent assay, serum estradiol by ultrasensitive radioimmunoassay, sex hormone binding globulin by radioimmunoassay, and BMD of the lumbar spine and the proximal femur by dual-energy X-ray absorptiometry. Active estrogen metabolites, 16alpha-hydroxyestrone (16alphaOHE(1)) and estriol (E(3)), positiv…
Correlation of Tibial Low-Frequency Ultrasound Velocity with Femoral Radiographic Measurements and BMD in Elderly Women
2009
The ultrasonic axial transmission technique has been proposed as a method for cortical bone characterization. Using a low enough center frequency, Lamb modes can be excited in long bones. Lamb waves propagate throughout the cortical bone layer, which makes them appealing for characterizing bone material and geometrical properties. In the present study, a prototype low-frequency quantitative ultrasonic axial transmission device was used on elderly women (n = 132) to investigate the relationships between upper femur geometry and bone mineral density (BMD) and tibial speed of sound. Ultrasonic velocities (V) were recorded using a two-directional measurement set-up on the midtibia and compared …
Bone mineral density, structure, distribution and strength in men with prostate cancer treated with androgen deprivation therapy
2019
Androgen deprivation therapy (ADT) improves survival in men with advanced prostate cancer (PCa), but has been associated with compromised skeletal health and increased fracture risk. However, limited previous research has investigated determinants of bone strength beyond DXA-derived areal bone mineral density (aBMD) in this population group. The aim of this cross-sectional study was to investigate the effects of ADT in men with PCa on BMD, bone structure, estimates of whole bone strength and cortical bone distribution. A total of 70 ADT-treated men, 52 PCa controls and 70 healthy controls had DXA lumbar spine and proximal femur aBMD and pQCT distal (4%) and proximal (66%) tibia and radius c…
Impaired geometric properties of tibia in older women with hip fracture history.
2007
This study evaluated side-to-side differences in tibial mineral mass and geometry in women with previous hip fracture sustained on average 3.5 years earlier. Both tibial mineral mass and geometry were found to be reduced in the fractured leg. INTRODUCTION: The purpose of this study was to evaluate side-to-side differences in tibial mineral mass and geometry after hip fracture and to assess the determinants of such differences. METHODS: Thirty-eight 60- to 85-year-old women with a previous hip fracture and 22 same-aged control women without fractures participated in the study. Bone characteristics of the distal tibia and tibial shaft of both legs were assessed using pQCT in order to compare …
Association of low 25-hydroxyvitamin D concentrations with elevated parathyroid hormone concentrations and low cortical bone density in early puberta…
2003
Background: Very few studies have evaluated both parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] and their effects on bone mass in children. Objective: We studied the associations of serum 25(OH)D and intact PTH (iPTH) with bone mineral content (BMC) and bone mineral density (BMD) at different bone sites and the relation between serum 25(OH)D and iPTH in early pubertal and prepubertal Finnish girls. Design: The subjects were 10‐12-y-old girls (n = 193) at Tanner stage 1 or 2, who reported a mean (± SD) dietary calcium intake of 733 ± 288 mg/d. 25(OH)D, iPTH, tartrate-resistant acid phosphatase 5b (TRAP 5b), urinary calcium excretion, BMC, areal BMD, and volumetric BMD were asses…
Does hysterectomy with ovarian conservation affect bone metabolism and density?
2002
We evaluated whether hysterectomy with ovarian conservation (HYX) has an effect on bone metabolism and density in 176 healthy Caucasian postmenopausal women aged 48-59 years. Bone properties of the hip, spine, radius, tibia, and calcaneus were measured using different bone assessment modalities. In addition, bone turnover was assessed using serum bone-specific alkaline phosphatase (BAP), osteocalcin (OC), and tartrate-resistant acid phosphatase (TRAP) 5b as biomarkers. Our results showed that women having HYX had a significantly lower level of OC ( P = 0.017) and a marginally lower level of TRAP 5b ( P = 0.051) and higher bone mineral density (BMD) of the femoral neck ( P = 0.037) and lumba…
Long Term Leisure Time Physical Activity Has a Positive Effect on Bone Mass Gain in Girls
2009
The purpose of this 7-year prospective longitudinal study was to examine whether the level and consistency of leisure-time physical activity (LTPA) during adolescence affected the bone mineral content (BMC) and bone mineral density (BMD) attained at early adulthood. The study subjects were 202 Finnish girls who were 10 to 13 years of age at baseline. Bone area (BA), BMC, and BMD of the total body (TB), total femur (TF), and lumbar spine (L2–L4) were assessed by dual-energy X-ray absorptiometry (DXA). Scores of LTPA were obtained by questionnaire. Girls were divided into four groups: consistently low physical activity (GLL), consistently high (GHH), and changed from low to high (GLH) and fro…
Positive association of high-density lipoprotein cholesterol with lumbar and femoral neck bone mineral density in postmenopausal women.
2021
Abstract Objective Experimental studies suggest that lipids affect bone metabolism. We aimed to elucidate whether lipid levels are associated with bone mineral density (BMD) in a cohort of postmenopausal women. Design A cross-sectional study of participants in the Chronic Ailment Reduction after MENopause (CARMEN) cohort. Women underwent assessment of clinical and analytical parameters, including fasting lipid levels. BMD was assessed at both lumbar spine and hip. Homogeneity in the cohort was optimized by filtering out a series of confounding variables with a known impact on bone. Main outcome measures Association of BMD at lumbar spine and femoral neck with lipid levels. Results A total o…
Bone mineral density of the proximal femur after hip resurfacing arthroplasty: 1-year follow-up study
2011
Abstract Background Hip resurfacing arthroplasty (HRA) is considered a bone-preserving procedure and may eliminate proximal femoral stress shielding and osteolysis. However, in addition to implant-related stress-shielding factors, various patient-related factors may also have an effect on bone mineral density (BMD) of the proximal femur in patients with HRA. Thus, we studied the effects of stem-neck angle, demographic variables, and physical functioning on the BMD of the proximal femur in a one-year follow-up. Methods Thirty three patients (9 females and 24 males) with a mean (SD) age of 55 (9) years were included in the study. BMD was measured two days and 3, 6, and 12 months postoperative…
Tetragonal tungsten bronzes Nb8−xW9+xO47−δ: optimization strategies and transport properties of a new n-type thermoelectric oxide
2015
Engineering of nanoscaled structures may help controlling the electrical and thermal transport in solids, in particular for thermoelectric applications that require the combination of low thermal conductivity and low electrical resistivity. The tetragonal tungsten bronzes Nb8−xW9+xO47 (TTB) allow a continuous variation of the charge carrier concentration while fulfilling at the same time the concept of a “phonon-glass electron-crystal” through a layered nanostructure defined by intrinsic crystallographic shear planes. The thermoelectric properties of the tetragonal tungsten bronzes Nb8−xW9+xO47−δ (0 < x < 2) were studied in the temperature range from 373 to 973 K. Structural defects and the…