Search results for " density"
showing 10 items of 2709 documents
Is bone loss the reversal of bone accrual? Evidence from a cross-sectional study in daughter-mother-grandmother trios.
2011
Bone adapts to mechanical loads applied on it. During aging, loads decrease to a greater extent at those skeletal sites where loads increase most in earlier life. Thus, the loss of bone may occur preferentially at sites where most bone has been deposited previously; ie, bone loss could be the directional reversal of accrual. To test this hypothesis, we compared the bone mass distribution at weight-bearing (tibia) and non-weight-bearing (radius) bones among 18-year-old girls, their premenopausal mothers, and their postmenopausal maternal grandmothers. Bone and muscle properties were measured by pQCT, and polar distribution of bone mass was obtained in 55 girl-mother–maternal grandmother trio…
Incidence of bisphosphonate-associated osteonecrosis of the jaws in breast cancer patients.
2009
BACKGROUND: Bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ) is a relatively new disease. The aim of this study was to evaluate the prevalence of BP-ONJ in breast cancer patients with osseous metastasis and bisphosphonate therapy. METHODS: A retrospective study was conducted in a EUSOMA accredited breast unit in Germany. All patients treated from January of 2000 to March of 2006 with metastatic breast cancer and bisphosphonate therapy were reviewed. All patients were contacted, and missing data were completed through structured interviews with their dentists and physicians (n = 75). Primary outcome was the development of BP-ONJ and the detection of possible additional trigger fa…
Differences between tight and loose cultures: a 33-nation study.
2011
With data from 33 nations, we illustrate the differences between cultures that are tight (have many strong norms and a low tolerance of deviant behavior) versus loose (have weak social norms and a high tolerance of deviant behavior). Tightness-looseness is part of a complex, loosely integrated multilevel system that comprises distal ecological and historical threats (e.g., high population density, resource scarcity, a history of territorial conflict, and disease and environmental threats), broad versus narrow socialization in societal institutions (e.g., autocracy, media regulations), the strength of everyday recurring situations, and micro-level psychological affordances (e.g., prevention …
Effect of undersized drilling on the stability of immediate tapered implants in the anterior maxillary sector. A randomized clinical trial.
2020
Background To evaluate the effect of undersized drilling on the primary and secondary stability of immediate implants placed in the anterior maxilla. Material and Methods A comparative randomized clinical trial was carried out in 30 healthy adults. Thirty tapered implants, 16 involving conventional drilling and 14 undersized drilling, were placed immediately after anterior maxillary tooth removal. Insertion torque and implant stability assessed by resonance frequency analysis (RFA) were evaluated at three different timepoints: at implant placement and 6 and 12 weeks post-implantation. The results were compared using parametric statistical tests. Results All implants showed adequate stabilit…
Long-term leisure time physical activity and properties of bone: A twin study
2009
Effects of physical activity on bone properties, when controlled for genetic effects, are not fully understood. We aimed to study the association between long-term leisure time physical activity (LTPA) and bone properties using twin pairs known to be discordant for leisure time physical activity for at least 30 yr. Volumetric BMD and geometric properties were measured at the tibia shaft and distal end using pQCT in 16 middle-aged (50-74 yr) same-sex twin pairs (seven monozygotic [MZ] and nine dizygotic [DZ] pairs) selected from a population-based cohort. Paired differences between active and inactive co-twins were studied. Active members of MZ twin pairs had larger cortical bone cross-secti…
Loading modalities and bone structures at nonweight-bearing upper extremity and weight-bearing lower extremity: a pQCT study of adult female athletes.
2005
This cross-sectional study of adult female athletes assessed whether the apparent loading-related differences in bone structure are primarily associated with the loading type or the muscle performance-related joint moments. Several structural variables at shaft sites of the tibia, radius and humerus, and distal sites of the tibia and radius were measured with peripheral quantitative computed tomography (pQCT) among 113 female national level athletes (representing hurdling, volleyball, soccer, racket-sports and swimming) and their 30 nonathletic referents. For the weight-bearing lower extremities, the loading modalities of the above sports were classified into high-impact (hurdling, volleyba…
Association between long-term exercise loading and lumbar spine trabecular bone score (TBS) in different exercise loading groups
2015
Objective: To examine whether different exercise loading is associated with lumbar vertebral texture as assessed with Trabecular Bone Score (TBS). Methods: Data from 88 Finnish female athletes and 19 habitually active women (reference group) were analyzed. Participants’mean age was 24.3 years(range 17-40 years).Athletes were divided into five specific exercise loading groups according to sport-specific training history: high-impact (triple jumpers and high jumpers), odd-impact (soccer players and squash players), high-magnitude (power lifters), repetitive impact (endurance runners), and repetitive non-impact (swimmers). TBS-values were determined from lumbar vertebral L1-L4 DXA images. Body…
Focal airtrapping at expiratory high-resolution CT: comparison with pulmonary function tests
2000
This study was undertaken to determine prevalence, extent, and severity of focal airtrapping at expiratory high-resolution CT, and to compare focal airtrapping with age, gender, pulmonary function tests, and blood gas analysis. Two-hundred seventeen patients with and without pulmonary disease underwent paired inspiratory/expiratory high-resolution CT. Six scan pairs with corresponding scan levels were visually assessed for focal – not diffuse – airtrapping using a four-point scale. Pulmonary function tests and blood gas analysis were available for correlation in all patients (mean interval 5 days). Focal airtrapping with lower lung predominance was observed in 80 % of patients. Twenty-six o…
A semi-automatic approach for epicardial adipose tissue segmentation and quantification on cardiac CT scans
2019
Abstract Many studies have shown that epicardial fat is associated with a higher risk of heart diseases. Accurate epicardial adipose tissue quantification is still an open research issue. Considering that manual approaches are generally user-dependent and time-consuming, computer-assisted tools can considerably improve the result repeatability as well as reduce the time required for performing an accurate segmentation. Unfortunately, fully automatic strategies might not always identify the Region of Interest (ROI) correctly. Moreover, they could require user interaction for handling unexpected events. This paper proposes a semi-automatic method for Epicardial Fat Volume (EFV) segmentation a…
In-vivo investigation of material quality of bone tissue by measuring apparent phalangeal ultrasound transmission velocity
1995
The square of ultrasound transmission velocity in a material is related to the modulus of elasticity, which is known to be an indicator of stability in bone. The aim of our study was to use ultrasound transmission velocity to obtain information about the material properties of bone tissue, keeping other factors possibly influencing ultrasound transmission as constant as possible. Apparent phalangeal ultrasound transmission velocity (APU) measured in 54 isolated, fresh pig phalanges was shown to be independent of bone mineral density (BMD) measured by SPA. Fastest sound transmission led exclusively through cortical bone so that intertrabecular connectivity in spongious bone could not influen…