Search results for "bones"
showing 10 items of 279 documents
Mutations in LMX1B cause abnormal skeletal patterning and renal dysplasia in nail patella syndrome
1998
The LIM-homeodomain protein Lmxlb plays a central role in dorso-ventral patterning of the vertebrate limb1. Targeted disruption of Lmxlb results in skeletal defects including hypoplas-tic nails, absent patellae and a unique form of renal dysplasia (see accompanying manuscript by H. Chen et al.; ref. 2). These features are reminiscent of the dominantly inherited skeletal malformation nail patella syndrome (NFS). We show that LMX1B maps to the NFS locus and that three independent NFS patients carry de novo heterozygous mutations in this gene. Functional studies show that one of these mutations disrupts sequence-specific DNA binding, while the other two mutations result in premature terminatio…
Association Between Exercise and Pubertal BMD Is Modulated by Estrogen Receptor α Genotype
2003
Genetic and environmental factors contribute to bone mass, but the ways they interact remain poorly understood. This study of 245 pre- and early pubertal girls found that the PvuII polymorphism in the ER- gene modulates the effect of exercise on BMD at loaded bone sites. Introduction: Impaired achievement of bone mass at puberty is an important risk factor for the development of osteoporosis in later life. Genetic, as well as environmental, factors contribute to bone mass, but the ways they interact with each other remain poorly understood. Materials and Methods: We investigated the interaction between a PvuII polymorphism at the ER- gene and physical activity (PA) on the modulation of bone…
Human histidine-rich glycoprotein expressed in SF9 insect cells inhibits apatite formation
1997
Histidine-rich glycoprotein (HRG) is structurally related to the alpha2-HS glycoprotein/fetuin family of mammalian plasma proteins; both belong to the cystatin superfamily of proteins. We expressed recombinant human HRG and alpha2-HS in Sf9 insect cells for functional analysis. Recombinant HRG bound heparin and fibrinogen while alpha2-HS did not. Both proteins inhibited the formation of apatite, recombinant HRG (IC50 approximately 1 microM) with 2-fold lower molar activity than alpha2-HS (IC50 approximately 0.5 microM). The inhibition in vitro of apatite formation suggests a new function for plasma HRG protein, inhibition of phase separation in blood vessels.
Beyond the functional matrix hypothesis: a network null model of human skull growth for the formation of bone articulations.
2014
Craniofacial sutures and synchondroses form the boundaries among bones in the human skull, providing functional, developmental and evolutionary information. Bone articulations in the skull arise due to interactions between genetic regulatory mechanisms and epigenetic factors such as functional matrices (soft tissues and cranial cavities), which mediate bone growth. These matrices are largely acknowledged for their influence on shaping the bones of the skull; however, it is not fully understood to what extent functional matrices mediate the formation of bone articulations. Aiming to identify whether or not functional matrices are key developmental factors guiding the formation of bone articu…
Depletion of alphaV integrins from osteosarcoma cells by intracellular antibody expression induces bone differentiation marker genes and suppresses g…
1999
Integrin heterodimers sharing the common alphaV subunit are receptors for adhesion glycoproteins such as vitronectin and fibronectin. They are suggested to play an essential role in cell anchoring, differentiation, and survival. Here, we describe the construction of an expression plasmid coding for an intracellular single-chain antibody against alphaV integrin subunit. Saos-2 osteosarcoma cells transfected with this DNA construct showed an approximately 70-100% decrease in the cell surface expression of alphaVbeta3 and alphaVbeta5 integrins as shown by flow cytometry. Intracellular antibody expression had no effect on the mRNA levels of alphaV integrin. Pulse chase experiments of metabolica…
To be or not to be heavier: The role of dermal bones in the buoyancy of the Late Triassic temnospondyl amphibian Metoposaurus krasiejowensis.
2022
Stereospondyli are a clade of large aquatic temnospondyls known to have evolved a large dermal pectoral girdle. Among the Stereospondyli, metoposaurids in particular possess large interclavicles and clavicles relative to the rest of the postcranial skel-eton. Because of the large size of these dermal bones, it was first proposed that they served as ballast during hydrostatic buoyancy control which assisted metoposaurids to live a bottom-dwelling mode of life. However, a large bone need not necessarily be heavy, for which determining the bone compactness becomes crucial for under-standing any such adaptation in these dermal bones. Previous studies on the evolu-tion of bone adaptations to aqu…
The synovial joints of the human foot.
2007
The human foot is considered an organ with an assortment of tissues with different morphological characteristics and well defined limits, but effectively has a simple functionality when static that becomes extremely complex when in movement. Its complex structure, comprised of an elastic and resistant skin covering a bone framework, joints, muscles, tendons, veins and nerves, can be compared to an efficient mechanical assembly. After a long and extraordinary evolutive journey, the human foot has undergone numerous changes to perfect its function; it has lost most of its grabbing function whilst gaining new characteristics that have ultimately allowed the modern man to stand upright. The com…
Aromatase Inhibitors Plus Weight Loss Improves the Hormonal Profile of Obese Hypogonadal Men Without Causing Major Side Effects
2020
Objective: In obese men, the increased expression of the aromatase enzyme in adipose tissue leads to high conversion of androgens to estrogens contributing to hypogonadotropic hypogonadism (HHG). Our objective is to evaluate efficacy and safety of weight loss (WL) plus aromatase inhibitor (AI) therapy in severely obese men with HHG. We hypothesize that AI+WL will be more effective as compared to WL alone in improving the hormonal profile, thus muscle strength and symptoms of HHG (primary outcomes), with no significant adverse effects on lean mass, metabolic profile, and bone mineral density (secondary outcomes).Design: Randomized double-blind placebo-controlled pilot trial.Methods: Twenty-t…
Treatment with soluble activin type IIB-receptor improves bone mass and strength in a mouse model of Duchenne muscular dystrophy.
2016
Background Inhibition of activin/myostatin pathway has emerged as a novel approach to increase muscle mass and bone strength. Duchenne muscular dystrophy (DMD) is a neuromuscular disorder that leads to progressive muscle degeneration and also high incidence of fractures. The aim of our study was to test whether inhibition of activin receptor IIB ligands with or without exercise could improve bone strength in the mdx mouse model for DMD. Methods Thirty-two mdx mice were divided to running and non-running groups and to receive either PBS control or soluble activin type IIB-receptor (ActRIIB-Fc) once weekly for 7 weeks. Results Treatment of mdx mice with ActRIIB-Fc resulted in significantly in…
Risk factors for pelvic insufficiency fractures and outcome after conservative therapy
2016
Abstract Purpose The prevalence of osteoporosis has continuously increased over the past decades and it is set to increase substantially as life expectancy rises steadily. Fragility or osteoporotic fractures of the pelvis often occur after low energy falls e.g. from standing, however, some patients present with assumed insufficiency fractures of the pelvis without a previous trauma. Osteoporotic fractures impose a tremendous economic burden and these fractures deserve attention as they lead to a decrease in mobility with an increase in dependency and are associated with a high rate of mortality. To date, little is known about potential risk factors for pelvic insufficiency fractures. Furthe…