Relative Handgrip Strength is Inversely Associated with Hypertension in Consideration of Visceral Adipose Dysfunction: A Nationwide Cross-Sectional Study in Korea

This study investigated the associations of relative handgrip strength (rHGS) and hypertension. Individual differences in visceral adipose dysfunction (VAD) were evaluated to verify whether rHGS was associated with a reduction in the risk of hypertension, even in individuals with VAD. We included 77,991 participants (50,616 women) from nationwide cohorts in Korea. Participants were categorized into three groups based on sex-specific tertiles of rHGS (Low, Mid, and High). The visceral adiposity index (VAI) was used to evaluate VAD. The multiple logistic regression model was used to assess the risk of hypertension. High rHGS is associated with reduction of hypertension risk in 38 and 26% of men and women, respectively, although rHGS was significantly low in women compared to men. The benefit of rHGS was observed from middle-aged to older participants in both sexes. High rHGS is associated with risk reduction for hypertension in both VAD and non-VAD groups. In the VAD group, compared to Low rHGS, High rHGS was associated with 32 and 22% risk reductions in hypertension in men and women, respectively, and these associations remained significant even when classified according to age, such as in middle-aged and older subgroups. Therefore, the present study suggests that high levels of rHGS are significantly associated with a reduced risk of hypertension even in participants with VAD. Thus, maintaining a higher level of rHGS may be associated with protective benefits against hypertension

Association of leisure-time physical activity and resistance training with risk of incident hypertension: The Ansan and Ansung study of the Korean Genome and Epidemiology Study (KoGES)

Hypertension is the most common preventable risk factor for the onset of cardiovascular disease and mortality. We aimed to investigate the association between incident hypertension and 4-year leisure-time physical activity (PA) levels and resistance training (RT). In this community-based Korean cohort, 5,075 participants without hypertension were included. To evaluate cumulative PA, the average PA time (the total time of moderate-intensity leisure-time PA) at baseline, 2-year follow-up, and 4-year follow-up were calculated. Based on participation in RT and compliance to PA guidelines (≥150 min/week of PA time), the participants were divided into the following four groups: Low-PA, Low-PA+RT, High-PA, and High-PA+RT. A multivariate Cox proportional hazards regression model was used to evaluate the 12-year incidence of hypertension in relation to leisure-time PA levels and RT regularity. During a mean 7.86 ± 4.20-year follow-up, 2,544 participants (1,366 women) were diagnosed with hypertension. Compared with Low-PA, High-PA, and High-PA+RT decreased the risk for hypertension by 30 and 39%, respectively. Participation in RT without compliance to PA guidelines did not affect the incidence of hypertension. The additive effect of RT on hypertension in the High-PA group was further examined. Although sex-based comparisons indicated that men had a significantly longer training period for RT than women, an additional reduction in the risk for hypertension in relation to the addition of RT was observed only in women (35%). PA may confer protective effects against hypertension, whereas the addition of RT to high levels of PA can further reduce the risk for hypertension in women

Biocorrosion and osteoconductivity of PCL/nHAp composite porous film-based coating of magnesium alloy

The present study was aimed at designing a novel porous hydroxyapatite/poly(epsilon-caprolactone) (nHAp/PCL) hybrid nanocomposite matrix on a magnesium substrate with high and low porosity. The coated samples were prepared using a dip-coating technique in order to enhance the bioactivity and biocompatibility of the implant and to control the degradation rate of magnesium alloys. The mechanical and biocompatible properties of the coated and uncoated samples were investigated and an in vitro test for corrosion was conducted by electrochemical polarization and measurement of weight loss. The corrosion test results demonstrated that both the pristine PCL and nHAp/PCL composites showed good corrosion resistance in SBF. However, during the extended incubation time, the composite coatings exhibited more uniform and superior resistance to corrosion attack than pristine PCL, and were able to survive severe localized corrosion in physiological solution. Furthermore, the bioactivity of the composite film was determined by the rapid formation of uniform CaP nanoparticles on the sample surfaces during immersion in SBF. The mechanical integrity of the composite coatings displayed better performance (similar to 34% higher) than the uncoated samples. Finally, our results suggest that the nHAp incorporated with novel PCL composite membranes on magnesium substrates may serve as an excellent 3-D platform for cell attachment, proliferation, migration, and growth in bone tissue. This novel as-synthesized nHAp/PCL membrane on magnesium implants could be used as a potential material for orthopedic applications in the future. (C) 2012 Elsevier Masson SAS. All rights reserved

Air jet spray of nylon 6 membrane structures for bone tissue engineering

A novel porous nylon 6 (N6) scaffold with high and low porosity was designed using a facile, one-step approach. The scaffold samples were prepared using air jet spray (AJS) to obtain high production rates as an alternative low cost, effective technique with precise thickness control. The present results show that AJS adequately produced interconnected porous networks ranging from micron to submicron scales that were observed using a scanning electron microscope. The effect of AJS on the secondary structure of N6 was examined to identify and quantify conformational changes that occurred due to processing. The mechanical properties of the fabricated samples were tested. The results of tensile tests indicated higher tensile strength of AJS scaffold than that of electrospun scaffold

Enhanced biocorrosion resistance of surface modified magnesium alloys using inorganic/organic composite layer for biomedical applications

Magnesium (Mg) is a very active element with low surface stability. Thus, the biocorrosion resistance of Mg and its alloys in electrolytic physiological environments is extremely poor, which is the main limitation preventing their use in biomedical applications. In addition, generating an appropriate protective layer to coat the surface of such materials is a challenge due to the low level of surface stability. The aim of this study was to prepare thin Ti-O films on Mg substrates using electron beam physical vapor deposition (EB-PVD) in order to improve the surface stability of Mg. To provide further corrosion resistance and facilitate improved bioactivity and biocompatibility, Ti-O thin films were subsequently coated with PLA as a top layer by dip-coating. The surface properties of the coated layers were characterized by AFM, X-RD, FTIR, SEM, and EDS. Furthermore, the biocorrosion characteristics of samples were measured by electrochemical corrosion and hydrogen evaluation tests in standard simulation body fluid (SBF) at 37.5 degrees C. Our results showed that incorporation of a composite layer significantly reduced the rate of degradation of Mg alloys, particularly during the initial immersion stages. The rates of hydrogen evolution of Mg bars with and without a Ti-O/PLA composite coating after 18 days was approximately 4.86 and 13.4 ml cm(-2), respectively. Together, these results demonstrated that surface treatment of Mg substrates with Ti-O and PLA, together with the associated changes of surface reactivity and chemistry, provide a viable strategy to facilitate cell survival on otherwise non-biocompatible Mg surfaces. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved

Biocorrosion behavior and cell viability of adhesive polymer coated magnesium based alloys for medical implants

The present study was ultimately aimed to design novel adhesive biodegradable polymer, poly(vinyl acetate) (PVAc), coatings onto Mg based alloys by the dip-coating technique in order to control the degradation rate and enhance the biocompatibility of magnesium alloys. The influence of various solvents on PVAc surface topography and their protection of Mg alloys were dramatically studied in vitro. Electrochemical polarization, degradation, and PVAc film cytocompatibility were also tested. Our results showed that the solvent had a significant effect on coating quality. PVAc/dichloromethane solution showed a porous structure and solution concentration could control the porous size. The coatings prepared using tetrahydrofuran and dimethylformamide solvents are exceptional in their ability to generate porous morphology even at low polymer concentration. In general, the corrosion performance appears to be different on different PVAc-solvent system. Immersion tests illustrated that the porous morphology on PVAc stabilized corrosion rates. A uniform corrosion attack in artificial simulation body fluid was also exhibited. The cytocompatibility of osteoblast cells (MC3T3) revealed high adherence, proliferation, and survival on the porous structure of PVAc coated Mg alloy, which was not observed for the uncoated samples. This novel PVAc coating is a promising candidate for biodegradable implant materials, which might widen the use of Mg based implants. Crown Copyright (C) 2012 Published by Elsevier B. V. All rights reserved