Search results for " density"

Effects of locally applied Insulin-like Growth Factor-I on osseointegration.

2019

Background The aim of this study was to assess the effect of local application of IGF-I on osseointegration of dental implants placed in osteoporotic bones. Material and Methods 16 rabbits were randomly distributed into two groups: eight animals were ovariectomized and fed a low-calcium diet for six weeks, in order to induce experimental osteoporosis, and the others were sham-operated and fed a standard diet. A titanium implant was inserted into the tibiae in both groups. In half of the rabbits, 4 μg of IGF-I was applied into the ostectomy, prior to the implant insertion. A total of 32 implants were placed. Animals were sacrificed two weeks after surgery and decalcified samples were process…

Ultrasound velocity and cortical bone characteristics in vivo.

2001

Axial transmission of ultrasound along cortical bone may reflect a combination of material and structural properties of long bone cortices. The goal of this study was to determine the association of speed of sound (SOS) with cortical density (CoD), cortical wall thickness (CWT), and total cortical area (CoA). Quantitative ultrasound (QUS) and peripheral quantitative computed tomography (pQCT) were used to measure the above variables in the distal third of radius and the midshaft of tibia in 51 postmenopausal women aged 62 to 71 years. Univariate regression analysis showed that the site-specific CoD accounted for 34% of the variability in the radial SOS and 29% of that in the tibial SOS (p0.…

Disc degeneration and bone density in monozygotic twins discordant for insulin-dependent diabetes mellitus

2000

The effects of insulin-dependent diabetes mellitus on bone density and connective tissue degeneration have theoretical interest and practical relevance. Several experimental studies in animals have demonstrated the harmful effects of insulin deficiency on connective tissues. However, clinical studies in humans have produced somewhat contradictory results, most likely due to difficulties controlling for general degeneration and factors associated with diabetes. In nine pairs of monozygotic twins discordant for insulin-dependent diabetes mellitus, we compared femoral and lumbar bone mineral density (assessed by dual-energy x-ray absorptiometry) and spinal degeneration (assessed by magnetic re…

Comparison of ultrasound and bone mineral density assessment of the calcaneus with different regions of interest in healthy early menopausal women.

1998

This study investigated the effect of different sized regions of interest (ROIs) on quantitative ultrasound (QUS) variables of the calcaneus. The effect on QUS of using a fixed ROI as opposed to an ROI adjusted for foot length was also assessed. Eighty Caucasian women, aged 50-57 yr (mean 53 +/- 2) who were healthy and within 0. 5-5 yr of the onset of menopause participated in this study. Using the QUS-1(trade mark) Ultrasonometer (Metra Biosystems, Mountain View, CA), we assessed broadband ultrasound attenuation ([BUA] and UBI-4, dB/MHz), the average transit time through the heel ([TTH], mus) and a multiple-factor index (UBI-4T = UBI-4/TTH, dB/[MHz. mus]). The QUS measurement results were …

Quantitative ultrasound predicts bone mineral density and failure load in human lumbar vertebrae

2006

Quantitative ultrasound is in widespread clinical use for assessment of bone quality at peripheral skeletal sites, but has not yet been applied to those sites in the axial skeleton, such as the spine and hip, where osteoporotic fractures are common.Ultrasound measurements were made in 11 cadaveric vertebrae and relationships with bone mineral density and failure load were investigated. An ultrasonic imaging system was used to measure speed of sound, broadband ultrasonic attenuation, and attenuation at a single frequency, through the vertebral body in the sagittal plane. Ultrasonic measurements were averaged over a region of interest centrally within the vertebral body, and were calculated w…

Do More Highly Organized Collagen Fibrils Increase Bone Mechanical Strength in Loss of Mineral Density After One-Year Running Training?

1999

The aim of this study was to evaluate the effects of long-term running training on the structural properties of bone. Ten beagle dogs ran according to a strenuous progressive program (up to 40 km/day) for 1 year. At the end of the training program, there was a significant reduction in bone mineral density (up to 9.7%) in the vertebrae of the runner dogs as compared with 10 sedentary control dogs. Polarized light microscopy of the vertebral trabecular bone, however, displayed proportionally higher retardation values of the collagen network of the runner dogs than of the sedentary dogs, suggesting a reorganization in a more parallel manner in the collagen fibrils. The concentration and cross-…

Serum and urine markers of type I collagen metabolism in elderly women with high and low bone mineral density.

1996

The serum markers of bone formation (carboxy-terminal propeptide of type I collagen, PICP) and resorption (pyridinoline cross-links containing telopeptide of type I collagen, ICTP), as well as urinary resorption markers, pyridinoline (Pyr) and deoxypyridinoline (Dpyr), were studied in 78-year-old women with high (n = 18) and low (n = 17) bone mineral density (BMD) measured from the calcaneus and tibia. The low-BMD group had higher values for PICP (P = 0 center dot 025), Pyr (P = 0 center dot 001) and Dpyr (P < 0 center dot 001) than the high-BMD group. No inverse relationship between these markers and BMD was, however, observed within the study groups. ICTP, Pyr and Dpyr correlated with eac…

Bone mineral density of the calcaneus in 70??? to 81-yr-old male athletes and a population sample

1991

Bone mineral content (BMC/W) and density (BMD) were studied in 70- to 81-yr-old active male endurance-trained (long-distance runners, cross-country skiers, N = 67), strength-trained (throwers, weight-lifters, N = 14), and speed-trained (sprinters, jumpers, N = 16) athletes. A population sample of similar age (N = 42) served as a control group. The measurements were performed at the calcaneus by single-energy photon absorption. The endurance-trained athletes had higher bone width and depth, and the strength and speed-trained athletes higher bone depth than the control subjects. The three groups of athletes showed 19-28% higher BMC (g.cm-1) and BMC/W (g.cm-2) than the control group (P less th…

Cauliflower hybrids for spring production in southern mediterranean area

2009

Evaluating equilibrium and non-equilibrium transport of bromide and isoproturon in disturbed and undisturbed soil columns.

2007

19 pages; International audience; In this study, displacement experiments of isoproturon were conducted in disturbed and undisturbed columns of a silty clay loam soil under similar rainfall intensities. Solute transport occurred under saturated conditions in the undisturbed soil and under unsaturated conditions in the sieved soil because of a greater bulk density of the compacted undisturbed soil compared to the sieved soil. The objective of this work was to determine transport characteristics of isoproturon relative to bromide tracer. Triplicate column experiments were performed with sieved (structure partially destroyed to simulate conventional tillage) and undisturbed (structure preserve…