Effect of duration and exogenous carbohydrate on gross efficiency during cycling.

The purpose of this investigation was to determine the effects of 2.5 hours of cycling with and without carbohydrate supplementation on gross efficiency (GE). Trained cyclists (N = 15) were tested for V(.

Segmentation of bone CT images and assessment of bone structure using measures of complexity.

A nondestructive and noninvasive method for numeric characterization (quantification) of the structural composition of human bone tissue has been developed and tested. In order to quantify and to compare the structural composition of bones from 2D computed tomography (CT) images acquired at different skeletal locations, a series of robust, versatile, and adjustable image segmentation and structure assessment algorithms were developed. The segmentation technique facilitates separation from cortical bone and standardizes the region of interest.

Synthesis and evaluation of potential CT (computer tomography) contrast agents for bone structure and microdamage analysis.

The design and synthesis of several novel X-ray contrast agents 1-3, developed for targeting bone structures, and in particularly microcracks in bones, using CT (Computer Tomography) detection is described. These contrast agents are based on the use of the well known triiodobenzene platform, which was conjugated into one or more phenyliminodiacetate moieties, which can be used to 'lock' onto bone matrices. Compounds 1-3 were all tested for their ability to visualise cracks in bone structures (bovine bones) using micro-CT imaging.

Cancellous bone structure of iliac crest biopsies following 370 days of head-down bed rest.

Introduction: Static bone histomorphometry was applied to existing iliac bone sections originating from a 370-d 5 degrees head-down bed rest experiment. This bed rest experiment is the longest ever to have been conducted. We hypothesized that bed rest would decrease cancellous bone volume fraction and that this effect would be reversed by countermeasures.

Microdamage in bone: surface analysis and radiological detection.

Microdamage accumulation leads to reduced bone strength and fracture. Intact, damaged and Rose Bengal stained cortical bone specimens were studied using SEM and EDXA imaging. SEM coupled with EDXA studies showed selective labelling of surface damage due to binding of dye at free lattice sites.

Stereological measures of trabecular bone structure: comparison of 3D micro computed tomography with 2D histological sections in human proximal tibial bone biopsies.

Stereology applied on histological sections is the 'gold standard' for obtaining quantitative information on cancellous bone structure. Recent advances in micro computed tomography (microCT) have made it possible to acquire three-dimensional (3D) data non-destructively. However, before the 3D methods can be used as a substitute for the current 'gold standard' they have to be verified against the existing standard.

Quantification of spatial structure of human proximal tibial bone biopsies using 3D measures of complexity.

Changes in trabecular bone composition during development of osteoporosis are used as a model for bone loss in microgravity conditions during a space flight. Symbolic dynamics and measures of complexity are proposed and applied to assess quantitatively the structural composition of bone tissue from 3D data sets of human tibia bone biopsies acquired by a micro-CT scanner. In order to justify the newly proposed approach, the measures of complexity of the bone architecture were compared with the results of traditional 2D bone histomorphometry.

Comparison of bone loss with changes of bone architecture at six different skeletal sites using measures of complexity.

We explore the structural deterioration of human bone tissue in osteoporosis as a model for bone loss in microgravity conditions. Measures of complexity are applied to quantify the structural composition of bone tissue at six different skeletal locations. The complexity of the bone architecture and the rate of its decay during the bone loss are analyzed and compared with each other at the different locations.

Bone modeling and structural measures of complexity.

We test sensitivity and powerfulness of recently suggested Structure Measures of Complexity (SMC) with simulated test objects, represented by simple structures or modelled on the basis of a real bone image. We check how these SMC reflect the local and global disordering processes, as well as a deterioration of the bone structure. We show that applications of SMC provide additional information about any changes of the bone structure in comparison to bone mineral density (BMD), and that they can be potentially helpful in the diagnosis of osteoporosis.

Visual analysis of trabecular bone structure.

Acquiring image data of bone biopsies by a micro-CT scanner is today a common technique. The amount of data to be assessed is huge. The task to assess quantitative measures requires a concise visualization.

Determinants of the size of incident vertebral deformities in European men and women in the sixth to ninth decades of age: the European Prospective Osteoporosis Study (EPOS).

Unlabelled: More severe vertebral fractures have more personal impact. In the European Prospective Osteoporosis Study, more severe vertebral collapse was predictable from prior fracture characteristics. Subjects with bi-concave or crush fractures at baseline had a 2-fold increase in incident fracture size and thus increased risk of a disabling future fracture.

Detecting microdamage in bone.

Fatigue-induced microdamage in bone contributes to stress and fragility fractures and acts as a stimulus for bone remodelling. Detecting such microdamage is difficult as pre-existing microdamage sustained in vivo must be differentiated from artefactual damage incurred during specimen preparation. This was addressed by bulk staining specimens in alcohol-soluble basic fuchsin dye, but cutting and grinding them in an aqueous medium.

Determinants of incident vertebral fracture in men and women: results from the European Prospective Osteoporosis Study (EPOS).

The aim of this analysis was to determine the influence of lifestyle, anthropometric and reproductive factors on the subsequent risk of incident vertebral fracture in men and women aged 50-79 years. Subjects were recruited from population registers from 28 centers across Europe. At baseline, they completed an interviewer-administered questionnaire and had lateral thoraco-lumbar spine radiographs performed.

[Age- and gender-related distribution of bone mineral density and mechanical properties of the proximal humerus].

Purpose: To evaluate age- and gender-related mechanical properties and bone mineral density (BMD) of the proximal humerus at different levels and regions.

Materials And Methods: Mechanical indentation testing, DXA, QCT, pQCT and the radiogrammetry (Cortical Index, CI) were carried out in 70 freshly harvested humeri from 46 human cadavers (23 females, 23-males; median age 70.5 years).

Incidence of vertebral fracture in europe: results from the European Prospective Osteoporosis Study (EPOS).

Vertebral fracture is one of the major adverse clinical consequences of osteoporosis; however, there are few data concerning the incidence of vertebral fracture in population samples of men and women. The aim of this study was to determine the incidence of vertebral fracture in European men and women. A total of 14,011 men and women aged 50 years and over were recruited from population-based registers in 29 European centers and had an interviewer-administered questionnaire and lateral spinal radiographs performed.

A statistical method to minimize magnification errors in serial vertebral radiographs.

Incident vertebral deformities are commonly defined by observed changes in height between measurements on two consecutive radiographs. However, conventional radiographs are subject to magnification, and this magnification may differ between films, leading to artifactual changes in height. In order to minimize this effect, it is common practice to record the spine-film and film-focus distances, and from this to calculate a magnification factor for each film.

Bone architecture assessment with measures of complexity.

Architectural changes in trabecular bone by osteoporosis were utilized as a model for the changes which probably occur in human bone while exposed to microgravity conditions. Although there are many concerns about microgravity-induced bone loss, little is known about the impact of microgravity on the three-dimensional architecture of the skeleton. 50 (level L3) and 57 (level L4) vertebral bones harvested from human cadavers were investigated by computed tomography (CT) and quantified in terms of bone mineral density (BMD).

Osteoporosis changes the amount of vertebral trabecular bone at risk of fracture but not the vertebral load distribution.

Study Design: A finite-element study to investigate the amount of trabecular bone at risk of fracture and the distribution of load between trabecular core and cortical shell, for healthy, osteopenic, and osteoporotic vertebrae.

Objectives: To determine differences between healthy, osteopenic, and osteoporotic vertebrae with regard to the risk of fracture and the load distribution.

Summary Of Background Data: The literature contains no reports on the effects of osteopenia and osteoporosis on load distribution in vertebral bodies, nor any reports on the amount of trabecular bone at risk of fracture.

Prevalent vertebral deformity predicts incident hip though not distal forearm fracture: results from the European Prospective Osteoporosis Study.

The presence of a vertebral deformity increases the risk of subsequent spinal deformities. The aim of this analysis was to determine whether the presence of vertebral deformity predicts incident hip and other limb fractures. Six thousand three hundred and forty-four men and 6788 women aged 50 years and over were recruited from population registers in 31 European centers and followed prospectively for a median of 3 years.

Measurement imprecision in vertebral morphometry of spinal radiographs obtained in the European Prospective Osteoporosis Study: consequences for the identification of prevalent and incident deformities.

Several algorithms are currently in use for evaluating vertebral deformities from plain lateral radiographs of the lumbar and thoracic spine. However, the effects of measurement imprecision as well as uncertainties over image magnification on the correct identification of prevalent and incident vertebral deformities with these algorithms has been little studied. In a pilot study for the European Prospective Osteoporosis Study (EPOS), plain radiographs were submitted to a single central evaluating centre for measurement of vertebral height from T4 to L4.

Serum leptin levels, body fat deposition, and weight in females with anorexia or bulimia nervosa.

The objective of this retrospective study was to investigate the relation between serum leptin level and fat deposition in patients with eating disorders. 40 female inpatients with anorexia (n=24) or bulimia nervosa (n=16) were assessed for leptin level, body mass index (BMI), and percentage body fat by dual-energy X-ray absorbometry (DXA). The results show that percentage body fat is a better predictor for leptin level and clinical findings in eating disordered patients than BMI.

[Bone densitometry by dual energy methods].

Osteoporosis is mainly diagnosed by means of bone densitometry. Dual X-ray absorptiometry examinations represent the basis for a highly reproducible and correct measurement. At present, densitometry is the only method at our disposal capable of assessing material-related fracture risk.

Measures of complexity for cancellous bone.

The problem of quantifying the structure of cancellous bone has been addressed in the past by histomorphometry and more recently by imaging techniques using X-ray attenuation. The current approaches compute and describe parts of the construction of the trabecular net. We developed a new technique which quantifies cancellous bone of human lumbar vertebrae as a whole.

Bone densitometry: applications in sports-medicine.

Physical exercise and sports increase muscular mass and the remodelling process of bones. The increment of bone depends on the type and the quality of sport. Short-term high-performance activities such as sprint, tennis, fencing lead to increased bone mineral density as well as weight lifting or heavy athletics.

[Prevalence of vertebral spinal deformities in women and men in Germany. EVOS group in Germany].

Background: The prevalence of radiographically defined vertebral deformities, as a marker of vertebral osteoporosis, was calculated in a population based cross-sectional survey in Germany.

Method: Lateral spine X-rays were taken according to a standardized protocol and evaluated centrally. Three thousand nine hundred and eighty subjects (2064 male and 1916 female) aged 50 to 79 years, have been examined in 8 German centers.