Age Related Variation in BMD and Trabecular Architecture Differs Between the Proximal Femur and Calcaneus in Men

2011 ◽  
Author(s):  
Hanna Isaksson ◽  
Viktoria Prantner ◽  
Jukka S. Jurvelin
Keyword(s):  
Structural Characteristics ◽  
Structural Parameters ◽  
Fragility Fractures ◽  
Mineral Density ◽  
Predictive Capacity ◽  
Age Related ◽  
Overall Resistance ◽  
Status Differences ◽  
Insight Into

Fragility fractures due to degradation of the bone tissue during aging or development of osteoporosis are responsible for significant morbidity and mortality in elderly patients. A variety of factors contribute to the overall resistance of bones to fracture, e.g. the bone quality. Traditionally, bone mineral density (BMD) as assessed by the dual energy x-ray absorptiometry (DXA) is the gold standard for osteoporosis diagnostics 1. However, BMD alone is insufficient to explain fracture risk in patients 2. Additional characterization of bone structural parameters may provide more insight into the predictive capacity of BMD with respect to bone structural parameters. Further, as various skeletal sites are used to assess bone status, differences in structural characteristics of skeletal sites should be addressed.

scholarly journals Association of vitamin D and osteocalcin levels in post-menopausal women with osteoporosis

2017 ◽  
Vol 6 (4) ◽  
pp. 1244
Author(s):  
Yogiraj Vaijanathrao Chidre ◽  
Amir Babansab Shaikh
Keyword(s):  
Vitamin D ◽  
Parathyroid Hormone ◽  
Vitamin D Deficiency ◽  
Fragility Fractures ◽  
Bone Fragility ◽  
Vitamin D Supplementation ◽  
Mineral Density ◽  
Age Related ◽  
Calcium Phosphorus ◽  
Post Menopausal

Background: Osteoporosis is a common age related problem especially in women, with a consequent increase in bone fragility and susceptibility to fracture. Apart from Calcium, another nutrient that plays an important role in the mineralization of skeleton in Vitamin D. Osteocalcin, which is produced primarily by osteoblasts during bone formation, is considered to be one of the markers for osteoporosis.Methods: 314 women above the age of 40 were included into the study. A thorough physical and clinical examination, assessment of vital parameters, anthropometry evaluation was done for all patients. Bone mineral density was calculated using central DXA osteodensitometer at lumbar spine L1-L4, hip and ultradistal radius (in some cases.). Blood samples were taken for the detection of ionized calcium, phosphorus, alkaline phosphatase, 25hydroxivitamin D (25 ODH) and serum parathyroid hormone (PTH) by chemiluminiscent assay. Bone markers such as osteocalcin were measured as required.Results: Out of the 314 women attending our OPD, 96 of them were diagnosed as having osteoporosis. 24 out of them had fragility fractures, mainly of the hip, and 82 had ostepenia. Elevated levels of calcium (8.96 mg/dl), parathyroid hormone (58.76 pg/ml) and osteocalcin (24.46 ng/ml) were observed. Vitamin D deficiency of ≤ 20 was seen in 59 (63%) of the cases, insufficient in 23 (24%) and only 12 (13%) of these women had normal Vitamin D levels.Conclusions: Osteocalcin is a promising marker for the detection of osteoporosis. There is a considerable Vitamin D deficiency among the women with osteoporosis, and it is under-treated. It is essential to provide Vitamin D supplementation to these women especially those who are at high risk for fragility fractures.

Effects of External Loading on the Morphology of the Yielded Regions in Trabecular Bone Predicted by FEA

2008 ◽  
Author(s):  
Xiutao Shi ◽  
Xiang Wang ◽  
Glen L. Niebur
Keyword(s):  
Trabecular Bone ◽  
High Stress ◽  
Tissue Level ◽  
External Loading ◽  
Trabecular Architecture ◽  
Mineral Density ◽  
Age Related ◽  
Insight Into ◽  
Increased Susceptibility

Osteoporosis is an age-related skeletal condition characterized by low bone mineral density and deterioration of the trabecular architecture leading to increased susceptibility to fracture [1]. Wolff hypothesized that trabecular architecture adapts to have its principal material axes aligned with the principal loading directions. Regions of experimentally labeled trabecular microdamage correspond to areas of high stress and strain calculated from FEA [2]. Studying the morphology of numerically predicted regions of tissue level yielding might provide insight into the role of trabecular architecture in the strength of trabecular bone.

scholarly journals A structural characterization of the isoniazidMycobacterium tuberculosisdrug target, Rv2971, in its unliganded form

2014 ◽  
Vol 70 (5) ◽  
pp. 572-577 ◽  
Author(s):  
Adam Shahine ◽  
Anggia Prasetyoputri ◽  
Jamie Rossjohn ◽  
Travis Beddoe
Keyword(s):  
Structural Characterization ◽  
Structural Characteristics ◽  
Structural Comparison ◽  
First Line ◽  
Substrate Specificities ◽  
Toxic Metabolites ◽  
Tim Barrel ◽  
Insight Into ◽  
Line Drug

Aldo-keto reductases (AKR) are a large superfamily of NADPH-dependent oxidoreductases and play a role in detoxification of toxic metabolites. Rv2971, an AKR inMycobacterium tuberculosis, has recently been identified as a target of isoniazid, a key first-line drug against tuberculosis. Here, the cloning, expression, purification, crystallization and structural characterization of Rv2971 are described. To gain insight into its function, the crystal structure of Rv2971 was successfully determined to 1.60 Å resolution in its unliganded form. The structure exhibits a TIM-barrel fold typical of AKRs, revealing structural characteristics essential for function and substrate specificities, allowing a structural comparison between Rv2971 and other mycobacterial AKRs.

scholarly journals Structural Characterization of an Archaeal Lipid Bilayer as a Function of Hydration and Temperature

2020 ◽  
Vol 21 (5) ◽  
pp. 1816
Author(s):  
Marta Salvador-Castell ◽  
Bruno Demé ◽  
Philippe Oger ◽  
Judith Peters
Keyword(s):  
Phase Transition ◽  
Relative Humidity ◽  
Lipid Bilayers ◽  
Self Assembly ◽  
Structural Characteristics ◽  
Scattering Length ◽  
Structural Parameters ◽  
Hydrophobic Region ◽  
Lamellar Phases

Archaea, the most extremophilic domain of life, contain ether and branched lipids which provide extraordinary bilayer properties. We determined the structural characteristics of diether archaeal-like phospholipids as functions of hydration and temperature by neutron diffraction. Hydration and temperature are both crucial parameters for the self-assembly and physicochemical properties of lipid bilayers. In this study, we detected non-lamellar phases of archaeal-like lipids at low hydration levels, and lamellar phases at levels of 90% relative humidity or more exclusively. Moreover, at 90% relative humidity, a phase transition between two lamellar phases was discernible. At full hydration, lamellar phases were present up to 70 °C and no phase transition was observed within the temperature range studied (from 25 °C to 70 °C). In addition, we determined the neutron scattering length density and the bilayer’s structural parameters from different hydration and temperature conditions. At the highest levels of hydration, the system exhibited rearrangements on its corresponding hydrophobic region. Furthermore, the water uptake of the lipids examined was remarkably high. We discuss the effect of ether linkages and branched lipids on the exceptional characteristics of archaeal phospholipids.

scholarly journals Effectiveness of Pilates and Yoga to improve bone density in adult women: A systematic review and meta-analysis

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251391
Author(s):  
Rubén Fernández-Rodríguez ◽  
Celia Alvarez-Bueno ◽  
Sara Reina-Gutiérrez ◽  
Ana Torres-Costoso ◽  
Sergio Nuñez de Arenas-Arroyo ◽  
...  
Keyword(s):  
Fragility Fractures ◽  
Risk Of Bias ◽  
Control Group ◽  
Pool Data ◽  
Ageing Population ◽  
Adult Women ◽  
Mineral Density ◽  
Post Intervention ◽  
Age Related ◽  
The Impact

Background The ageing population brings about the appearance of age-related health disorders, such as osteoporosis or osteopenia. These disorders are associated with fragility fractures. The impact is greater among postmenopausal women due to an acceleration of bone mineral density (BMD) loss. Objective To estimate the effectiveness of Pilates or Yoga on BMD in adult women. Methods Five electronics databases were searched up to April 2021. Randomized controlled trials (RCTs), non-RCTs and pre-post studies were included. The main outcome was BMD. Risk of bias was evaluated using the Cochrane risk of bias tool. A random effects model was used to pool data from primary studies. Subgroup analyses based on the type of exercise were conducted. Results Eleven studies including 591 participants aged between 45 and 78 years were included. The mean length of the interventions ranged from 12 to 32 weeks, and two studies were performed for a period of at least one year. The pooled effect size for the effect of the intervention (Pilates/Yoga) vs the control group was 0.07 (95% Confidence interval [CI]: -0.05 to 0.19; I2 = 0.0%), and 0.10 (95% CI: 0.01 to 0.18; I2 = 18.4%) for the secondary analysis of the pre-post intervention. Conclusions Despite of the non-significant results, the BMD maintenance in the postmenopausal population, when BMD detrimental is expected, could be understood as a positive result added to the beneficial impact of Pilates-Yoga in multiple fracture risk factors, including but not limited to, strength and balance.

INTERMITTENT OPERATION OF LINEAR DRIVEN SWITCHED SYSTEMS

2008 ◽  
Vol 18 (02) ◽  
pp. 495-508 ◽  
Author(s):  
I. CERVANTES ◽  
R. FEMAT
Keyword(s):  
Continuous Time ◽  
Switched Systems ◽  
Structural Characteristics ◽  
Continuous Systems ◽  
System Parameters ◽  
Intermittent Operation ◽  
Piecewise Continuous ◽  
Insight Into ◽  
Oscillatory Path

The phenomenon of breathing (intermittent operation) is studied in a class of piecewise continuous systems as well as its relation with system parameters. The class of systems under study comprises a continuous time subsystem and a switching rule that induces an oscillatory path by switching alternately between stable and unstable conditions. An interesting feature of the system is that eigenvalues of linear subsystems play an important role in system evolution. It is shown that although regular and chaotic phases evolve irregularly for a given system, their average behavior is surprisingly regular with respect to a bifurcation parameter. It is found that the phenomenon of breathing share some structural characteristics with intermittency; i.e. existence of a critical exponent. However, for switched systems, many critical exponents may be required. Bifurcation maps and other analysis tools allow us to gain insight into the origin of breathing. This work constitutes a first step toward the characterization of intermittent operation in piecewise continuous systems.

scholarly journals Basis of bone strength vs. bone fragility: A review of determinants of age-related hip fracture risk

2013 ◽  
Vol 141 (7-8) ◽  
pp. 548-552 ◽  
Author(s):  
Danijela Djonic ◽  
Petar Milovanovic ◽  
Marija Djuric
Keyword(s):  
Fracture Risk ◽  
Bone Strength ◽  
Hip Fractures ◽  
Elderly Population ◽  
Structural Parameters ◽  
The Elderly ◽  
Bone Fragility ◽  
Clinical Settings ◽  
Mineral Density ◽  
Age Related

The burden of hip fractures in elderly population has been growing worldwide. A particular focus has been directed towards identifying persons at high risk of fracture. However, bone mineral density (BMD), which is currently used in clinical settings as an indicator of risk of age-related fracture, cannot explain all fracture cases in the elderly. In fact, the risk of hip fractures in the elderly is associated with numerous bone features that degrade bone strength. This review focuses on complexity of bone features that could account for increased bone fragility in advanced age. Besides a decrease in BMD, various macroscopic and microscopic structural parameters, as well as the material of which the bone is composed, are subject to age-related changes. Therefore, in order to have a more thorough assessment of the fracture risk, it is essential to provide integrative approaches that combine BMD measure with other relevant bone features.

171Intravascular polarimetry in patients with coronary artery disease: a first-in-human pilot study

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
K Otsuka ◽  
M Villiger ◽  
A Karanasos ◽  
L J C Van Zandvoort ◽  
P Doradla ◽  
...  
Keyword(s):  
Pilot Study ◽  
Clinical Presentation ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Structural Features ◽  
Plaque Morphology ◽  
Cross Sectional ◽  
Research Fellowship ◽  
Coronary Syndrome ◽  
Insight Into

Abstract Background Polarization-sensitive (PS-) optical frequency domain imaging (OFDI) measures polarization properties of tissue together with conventional cross-sectional OFDI images of subsurface microstructure. PS-OFDI offers refined insight into plaque morphology and composition, which are implicated in the pathogenesis of acute coronary syndromes (ACS). Purpose This first-in-human pilot study of intravascular polarimetry aimed to investigate birefringence and depolarization features of coronary plaques in patients and to examine the relationship of these features with established structural characteristics available to conventional OFDI and with clinical presentation. Methods 30 patients undergoing PS-OFDI (acute coronary syndrome; ACS, n=12 and stable angina pectoris; SAP, n=18) participated in this study. 342 cross-sectional images evenly distributed along all imaged coronary arteries were classified into one of seven plaque categories according to conventional OFDI. Polarization features averaged over the entire intimal area of each cross-section were compared between plaque types and with structural parameters. Further, we assessed the polarization properties in the fibrous caps of ACS and SAP culprit lesions and compared them with structural features using a generalized linear model. Results The median birefringence and depolarization showed statistically significant differences among plaque types (both p<0.001, one-way ANOVA). Depolarization significantly differed between individual plaque types (p<0.05), except between fibro-fatty and fibro-calcified plaques. Caps of ACS lesions and ruptured caps exhibited lower birefringence than caps of SAP lesions (p<0.01). In addition to clinical presentation, cap birefringence also associated with macrophage accumulation as assessed by normalized standard deviation. Intravascular polarimetry Conclusions Intravascular polarimetry provides quantitative metrics that help to characterize coronary arterial tissues and may offer refined insight into coronary arterial atherosclerotic lesions in patients (Figure). Quantitative assessment of plaque polarization properties by intravascular polarimetry may open new avenues for studying plaque progression and detecting high-risk patients. Acknowledgement/Funding The JSPS Overseas Research Fellowship, the Uehara Memorial Foundation, and the Japan Heart Foundation and Bayer Yakuhin

scholarly journals Evaluation of the Reactivity and Receptor Competition of HLA-G Isoforms toward Available Antibodies: Implications of Structural Characteristics of HLA-G Isoforms

2019 ◽  
Vol 20 (23) ◽  
pp. 5947 ◽  
Author(s):  
Atsushi Furukawa ◽  
Manami Meguro ◽  
Rika Yamazaki ◽  
Hiroshi Watanabe ◽  
Ami Takahashi ◽  
...  
Keyword(s):  
Dissociation Constants ◽  
Splice Variants ◽  
Structural Characteristics ◽  
Functional Characterization ◽  
Detection Systems ◽  
Intrinsically Disordered ◽  
Checkpoint Molecule ◽  
Maternal Immune Response ◽  
Insight Into

The human leucocyte antigen (HLA)-G, which consists of seven splice variants, is a tolerogenic immune checkpoint molecule. It plays an important role in the protection of the fetus from the maternal immune response by binding to inhibitory receptors, including leukocyte Ig-like receptors (LILRs). Recent studies have also revealed that HLA-G is involved in the progression of cancer cells and the protection from autoimmune diseases. In contrast to its well characterized isoform, HLA-G1, the binding activities of other major HLA-G isoforms, such as HLA-G2, toward available anti-HLA-G antibodies are only partially understood. Here, we investigate the binding specificities of anti-HLA-G antibodies by using surface plasmon resonance. MEM-G9 and G233 showed strong affinities to HLA-G1, with a nM range for their dissociation constants, but did not show affinities to HLA-G2. The disulfide-linker HLA-G1 dimer further exhibited significant avidity effects. On the other hand, 4H84 and MEM-G1, which can be used for the Western blotting of HLA-G isoforms, can bind to native HLA-G2, while MEM-G9 and G233 cannot. These results reveal that HLA-G2 has a partially intrinsically disordered structure. Furthermore, MEM-G1, but not 4H84, competes with the LILRB2 binding of HLA-G2. These results provide novel insight into the functional characterization of HLA-G isoforms and their detection systems.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

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