Myoconductive and osteoinductive free-standing polysaccharide membranes

Free-standing (FS) membranes have increasing applications in the biomedical field as drug delivery systems for wound healing and tissue engineering. Here, we studied the potential of free-standing membranes made by the layer-by-layer assembly of chitosan and alginate to be used as a simple biomimetic system of the periosteum. The design of a periosteum-like membrane implies the elaboration of a thick membrane suitable for both muscle and bone formation. Our aim was to produce well-defined ∼50 μm thick polysaccharide membranes that could be easily manipulated, were mechanically resistant, and would enable both myogenesis and osteogenesis in vitro and in vivo. The membranes were chemically crosslinked to improve their mechanical properties. Crosslinking chemistry was followed via Fourier transform infrared spectroscopy and the mechanical properties of the membranes were assessed using dynamic mechanical analysis. The loading and release of the potent osteoinductive growth factor bone morphogenetic protein 2 (BMP-2) inside and outside of the FS membrane was followed by fluorescence spectroscopy in a physiological buffer over 1 month. The myogenic and osteogenic potentials of the membranes in vitro were assessed using BMP-2-responsive skeletal myoblasts. Finally, their osteoinductive properties in vivo were studied in a preliminary experiment using a mouse ectopic model. Our results showed that the more crosslinked FS membranes enabled a more efficient myoblast differentiation in myotubes. In addition, we showed that a tunable amount of BMP-2 can be loaded into and subsequently released from the membranes, depending on the crosslinking degree and the initial BMP-2 concentration in solution. Only the more crosslinked membranes were found to be osteoinductive in vivo. These polysaccharide-based membranes have strong potential as a periosteum-mimetic scaffold for bone tissue regeneration.This work was financially supported by the Foundation for Science and Technology (FCT) through the scholarship SFRH/BPD/96797/2013, Fundo Social Europeu (FSE), and Programa Diferencial de Potencial Human (POPH) granted to Sofia G. Caridade. C.M. is indebted to the Association Francaise contre les Myopathies for financial support via a post-doctoral fellowship (AFM project 16673). J.A. acknowledges the Whitaker International Fellows and Scholars Program for support via a post-doctoral fellowship. This work was supported by the European Commission (FP7 program) via a European Research Council starting grant (BIOMIM, GA 259370 to C.P.) and by the AFM (grant Microtiss, 16530). We thank Isabelle Paintrand for her technical help with the confocal apparatus

Diagenesis of archaeological bone and tooth

An understanding of the structural complexity of mineralised tissues is fundamental for exploration into the field of diagenesis. Here we review aspects of current and past research on bone and tooth diagenesis using the most comprehensive collection of literature on diagenesis to date. Environmental factors such as soil pH, soil hydrology and ambient temperature, which influence the preservation of skeletal tissues are assessed, while the different diagenetic pathways such as microbial degradation, loss of organics, mineral changes, and DNA degradation are surveyed. Fluctuating water levels in and around the bone is the most harmful for preservation and lead to rapid skeletal destruction. Diagenetic mechanisms are found to work in conjunction with each other, altering the biogenic composition of skeletal material. This illustrates that researchers must examine multiple diagenetic pathways to fully understand the post-mortem interactions of archaeological skeletal material and the burial environment

The Mineral Phase: Calcified Microsphere Populations in Young and Ageing, Hard and Soft Tissues

There is the tendency with time for hard tissues to soften and soft tissues to harden 'With potential pathological consequences. Comparison of the mineral phase in bot.h may' provide novel insight into associated untreatable conditions of aging. The human proximal femur (the most vulnerable skeletal site) from nonfracture (osteoarthritis), fracture (osteoporosis) and normal subjects was examined, together 'With the human neonatal-TMJ and bone from functionally different skeletal locations in the rat, as wen as human dentine; soft tissues included human and sheep aorta, and sheep intervertebral disc and trachea. Histological methods encompassed plain and polarised light microscopy, epi-fluorescence microscopy, laser confocal microscopy with density gradient mapping, histochemistry and immunohistochemistry, together 'With SEM and TEM and EDXmicroanalysis of elements. These were applied to resin-embedded undecalcified sections, cryosectiGus' and mineral particle isolates separated from the tissue by hydrazine or sodium hydroxide digestion, or prepared synthetically. The results support the view that bone mineral does not consist of random uniform crystals. Population of calcified microspheres, about 1Ilm diameter, occurred in sections and isolates, singly, in bridged assemblies (10IlID long) and compressed into irregular domains or rounded macrosphere domains (30llm diameter). Apparently derived from dense nanospheres (50nm diameter) the microspheres are cell fabrications enclosing a filamentous substructure of 5nm beads. They varied with pathology, being larger (l-5Ilm) in osteoarthritis, and smaller (O.5-1Ilm) in osteoporosis, and the extent of their bridging increased in weight-bearing locations relative to non-weight-bearing sites. They generally lacked the uniform electron density and crystal-like nature of synthetic preparations, except in traces which increase with pathology or chemical exposure. There were some differences of degree with calcified microspheres populations in soft tissues. For example the CaIP ratio was more variable (1.17-2.59 cf. 1.52-1.54) while Mg, Si and Fe were regularly associated with both, Mg was particularly abundant in the calcified particles in the aorta and intervertebral disc. They did not permeate the collagen fibres but in their assemblies and convoluted domains looped around them to form a remarkably varied composite. Of special interest in this regard was the periosteum. Known to be as proactive in development of the skeleton, the results suggested it is a key determinant of its mass and maintenance as a periosteumSharpey's fibre-endosteum integrated system, rich in collagen type III that may function as a sensory avenue for musculoskeletal exchange. Contrasting features of this system are considered in osteoporosis, where it seems too tenuous and in osteoarthritis where it seems too robust. It was concluded that in the connective tissues neither the hard inorganic,phase nor the soft collagenous matrix are the homogeneous substances they are regularly portrayed to be. Their partnership in the young is optimal and beneficial in terms of structural strength and metabolic exchange but with age minor discord in this new histological facet to bone biology may lead to major disability and the challenge this presents for an aging populace.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Insulin resistance and obesity among infertile women with different polycystic ovary syndrome phenotypes

AbstractPolycystic ovary syndrome (PCOS) is a common problem among Arab women and is the main cause of infertility due to anovulation. This study investigates insulin resistance (IR) and obesity in different PCOS phenotypes among infertile women (n = 213), of whom 159 had PCOS and 54 women without PCOS, recruited as a control group. Biometric, hormonal and clinical parameters were studied. IR was observed in 133 (83.6%) women with PCOS and in 25 (46.3%) women without PCOS (p &lt; 0.001). IR was significantly associated with PCOS only among women with central obesity (χ2 = 35.0, p &lt; 0.001) and not for the normal category (χ2 = 4.04, p &lt; 0.058). The LH/FSH ratio was not significantly different among the PCOS group (n = 37, 23.3%) compared to the control group (n = 9, 16.7%) (p = 0.308). Among women with PCOS, the most common phenotype was type I (50.3%), with type III (29.6%), type II (14.5%) and type IV (5.7%). Type I had the highest values of fasting insulin (median = 12.98 mU/mL) and HOMA IR values (significant difference among the four phenotypes, p = 0.009 and 0.006, respectively) and is associated with severity of the disease. There was no difference in glucose levels.</jats:p

Preventive Effects of Dietaryraisins on Steroid - Induced Bone Changes in Rats

Glucocorticoids is the most common cause of secondary osteoporosis. Osteoporosis is widespread, costly and causes pain, deformity and disability. Several studies report health benefits of raisins. Raisins have a combination of compounds with antibacterial, antioxidant,anticarcinogenic and anti-inflammatory properties. The present study investigated the impact of Raisins onmethylprednisolone-induced osteoporosis in rats. Thirty male albino rats were randomly divided into three main groups, ten rats each. Group I control group; Group II, osteoporotic group, where osteoporosis was induced by injection of methylprednisolone; Group III, protected group, animals were given raisinsconcomitant daily with methylprednisolone. Bone biochemical markers were assisted, hydroxyproline, urinary calcium excretion, serum calcium, alkaline phosphatase and osteocalcin. In addition to histological findings in lumbar vertebrae of the rats.Our findings showed that raisin has a positive osteoprotective effects on methylprednisolone induced bone changes histologically and over the biomarkers examined.This study suggests that dietary raisins may moderate methylprednisolone bone induced changes.</jats:p

A new tool for early diagnosis of rheumatoid arthritis using combined biomarkers; synovial MAGE-1 mRNA and serum anti-CCP and RF

Introduction:&nbsp;rheumatoid arthritis (RA) is a common autoimmune disease with unknown etiology and pathogenesis. Biomarkers have the potential to aid in the clinical diagnosis of the disease, or to provide means of detecting early signs of the disease. Evaluating Melanoma associated antigen genes (MAGE-1) mRNA expression rate in synovial fluid cells and serum levels of anti-cyclic citrullinated peptides (anti-CCP) and rheumatoid factor (RF) for RA early diagnosis. Methods:&nbsp;a total of 213 subjects were enrolled in the study, 135 RA patients and 78 normal subjects with traumatic knee joints (control group). Serum RF and anti-CCP were estimated quantitatively using ELISA. MAGE-1 mRNA expression rate was analyzed by RT-PCR. Results:&nbsp;a significant increase in serum levels of RF IgM and anti-CCP in RA patients compared to the controls. A positively significant correlation was found between serum anti-CCP and RF IgM. The expression rate of MAGE-1 mRNA was 100% in RA patients versus the controls (0%). The specificity and the sensitivity of the three biomarkers was 100%. Conclusion:&nbsp;the high expression rate of MAGE-1 in synovial fluid cells of RA patients is encouraging its utilization as a diagnostic biomarker for RA. The combined use of MAGE-1 transcript in synovial fluid cells, serum RF and anti-CCP is recommended for improving early diagnostic ability of RA