Association of regulator of G protein signaling (RGS5) gene variants and essential hypertension in Mongolian and Han populations

Genetic variants of the RGS5 gene are believed to be risk factors for hypertension and cardiovascular diseases. In this study, we investigated the association between RGS5 gene variants and hypertension in the Mongolian and Han populations. Peripheral blood was obtained from 429 unrelated Mongolian herdsmen and 416 Han farmers [including essential hypertension (EH) patients and controls]. Nine tagSNPs within the RGS5 genes were retrieved from HapMap, and the samples were individually genotyped using the polymerase chain reaction/ligase detection reaction assay. The distribution of the allele frequency of rs12035879 differed significantly between hypertensive subjects and controls in the Han population, while the distribution of the allele and genotype frequencies of rs16849802 differed significantly between hypertensive subjects and controls in the Mongolian population. We observed an association between rs16849802 and EH in the Mongolian population. The frequency of haplotype GAA was significantly higher in the EH group than in controls in the Mongolian population. However, the EH group and controls did not differ significantly in all 6 haplotypes in the Han population. The rs16849802 and haplotype GAA independently increased the risk of EH in Mongolian patients, and may be used as a risk factor for the prediction of high blood pressure.

Differential effects of low-magnitude high-frequency vibration on reloading hind-limb soleus and gastrocnemius medialis muscles in 28-day tail-suspended rats

OBJECTIVES

Low-magnitude high-frequency vibration (LMHFV) was reported beneficial to muscle contractile functions in clinical and preclinical studies. This study aims to investigate the effects of LMHFV on myofibers, myogenic cells and functional properties of disused soleus (Sol) and gastrocnemius medialis (GM) during reloading.

METHODS

Sprague Dawley rats were hind-limb unloaded for 28 days and assigned to reloading control (Ctrl) or LMHFV group (Vib). Sol and GM of both groups were harvested for fiber typing, proliferating myogenic cell counting and in vitro functional assessment.

RESULTS

Myogenic cells proliferation was promoted by LMHFV in both Sol and GM (p<0.001 and p<0.05 respectively). Force generating capacity was not much affected (Vib=Ctrl, p>0.05) but fast-fiber favorable changes in fiber type switching (more type IIA but lower type I in Vib; p<0.05 and 0.01 respectively) and fiber hypertrophy (type I, Vib<Ctrl; p<0.01) were observed mainly in GM.

CONCLUSION

LMHFV was not detrimental to reloading muscles but the outcomes were muscle dependent. The unique fiber type composition and anatomical differences between Sol and GM might render the differential muscle responses to LMHFV. Further investigations on myofibers type specific responses to different LMHFV regimes and myogenic cell interaction with associated myofiber were proposed.

Effects and mechanism of lipoic acid on beta-amyloid-intoxicated C6 glioma cells

β-amyloid peptides (Aβs) can exert neurotoxic effects through induction of oxidative damage, whereas lipoic acid (LA), a powerful antioxidant, can alleviate oxidative damage. In this study, we explored the effect and mechanism of action of LA on beta-amyloid-intoxicated C6 glioma cells. Cells were randomly divided into three groups: control (vehicle), Aβ, and LA + Aβ. The LA + Aβ group was treated with LA for 2 h, then both the Aβ-only and the LA + Aβ groups were incubated with 25 μM Aβ for 24 h. Cell viability was measured by the MTT method. Mitochondrial reduced glutathione (GSH) and oxidized glutathione (GSSG) levels were detected by enzyme-linked immunosorbent assay (ELISA), and the GSH to GSSG ratio calculated. Real-time polymerase chain reaction and western blot analyses were used to detect MnSOD mRNA and protein, respectively. Aβ significantly inhibited C6 cell proliferation compared with the control group (P < 0.05). LA markedly increased cell viability compared with the Aβ group (P < 0.05). The increased GSSH and decreased GSH mitochondrial accumulation induced by Aβ was profoundly reversed by treatment with LA (P < 0.05). Aβ significantly reduced MnSOD expression compared to controls (P < 0.05), whereas LA pretreatment increased MnSOD expression compared with the Aβ-only group (P < 0.05); MnSOD protein levels showed similar patterns. These results suggest that LA might protect Aβ-intoxicated C6 glioma cells by alleviating oxidative damage, providing a new treatment strategy for neurodegenerative diseases.

Abnormal Bone Mechanical and Structural Properties in Adolescent Idiopathic Scoliosis: A Study with Finite Element Analysis and Structural Model Index

Previous studies found adolescent idiopathic scoliosis (AIS) is associated with low bone mineral density (BMD) and abnormal bone quality, whilst the association between AIS and their bone strength is unknown. From high-resolution peripheral quantitative computed tomography-generated images, bone mechanical properties can be evaluated with finite element analysis (FEA), and trabecular rod-plate configuration related to trabecular bone strength can be quantified by structure model index (SMI). This study aimed to compare trabecular configuration and bone mechanical properties between AIS and the controls. 95 AIS girls aged 12-14 years and 97 age- and gender-matched normal controls were recruited. Bilateral femoral necks and non-dominant distal radius were scanned by dual-energy X-ray absorptiometry for areal BMD and HR-pQCT for SMI and FEA, respectively. Subjects were further classified into osteopenic and non-osteopenic group based on their areal BMD. Bone mechanical properties (stiffness, failure load and apparent modulus) were calculated using FEA. Linear regression model was used for controlling age, physical activity and calcium intake. AIS was associated with lower failure load and apparent modulus after adjusting for age, whereas AIS was associated with lower apparent modulus after adjusting for all confounders. Osteopenic AIS was associated with more rod-like trabeculae when compared with non-osteopenic AIS, whereas no difference was detected between osteopenic and non-osteopenic controls. This might be the result of abnormal regulation and modulation of bone metabolism and bone modelling and remodelling in AIS which will warrant future studies with a longitudinal design to determine the significance of micro-architectural abnormalities in AIS.

Age-related differences in volumetric bone mineral density, microarchitecture, and bone strength of distal radius and tibia in Chinese women: a high-resolution pQCT reference database study

In a cohort of 393 Chinese women, by using high-resolution peripheral quantitative computed tomography (HR-pQCT), we found that significant cortical bone loss occurred after midlife. Prominent increase in cortical porosity began at the fifth decade but reached a plateau before the sixth decade. Trabecular bone loss was already evident in young adulthood and continued throughout life.

INTRODUCTION

This study aimed to investigate age-related differences in volumetric bone mineral density (vBMD), microarchitecture, and estimated bone strength at peripheral skeleton in Chinese female population.

METHODS

In a cross-sectional cohort of 393 Chinese women aged 20-90 years, we obtained vBMD, microarchtecture, and micro-finite element-derived bone strength at distal radius and tibia using HR-pQCT.

RESULTS

The largest predictive age-related difference was found for cortical porosity (Ct.Po) which showed over four-fold and two-fold differences at distal radius and tibia, respectively, over the adulthood. At both sites, cortical bone area, vBMD, and thickness showed significant quadratic association with age with significant decrease beginning after midlife. Change of Ct.Po became more prominent between age of 50 and 57 (0.26 %/year at distal radius, 0.54 %/year at distal tibia, both p ≤ 0.001) but thereafter, reached a plateau (0.015 and 0.028 %/year, both p > 0.05). In contrast, trabecular vBMD and microarchitecture showed linear association with age with significant deterioration observed throughout adulthood. Estimated age of peak was around age of 20 for trabecular vBMD and microarchitecture and Ct.Po and age of 40 for cortical vBMD and microarchitecture. Estimated stiffness and failure load peaked at mid-30s at the distal radius and at age 20 at distal tibia.

CONCLUSIONS

Age-related differences in vBMD and microarchitecture in Chinese women differed by bone compartments. Significant cortical bone loss occurred after midlife. Prominent increase in Ct.Po began at the fifth decade but appeared to be arrested before the sixth decade. Loss of trabecular bone was already evident in young adulthood and continued throughout life.

Effect of daily short-duration weight-bearing on disuse-induced deterioration of musculoskeletal system

OBJECTIVES

To investigate deterioration of musculoskeletal system due to prolonged disuse and the potential of daily short-duration weight-bearing as countermeasures.

METHODS

Twenty-four adult male Sprague-Dawley rats were divided into Control Group (CG, no intervention), Tail-suspension Group (TG, tail-suspension without treatment), and Weight-Bearing Group (WBG, tail-suspension with 20 min/day, 5 days/week body weight loading). After four weeks of treatment, femur and tibia, soleus and extensor digitorum longus were evaluated for bone and muscle quality respectively. Tensile properties of bone-tendon insertion (BTI) were evaluated using patella-patellar tendon complex.

RESULTS

Disuse induced deterioration on bone, muscle, and BTI after four weeks. Compared with CG, TG and WBG showed significant decrease in bone mineral density (BMD) of trabecular bone in distal femur (4.3-15.2%), muscle mass (31.3-52.3%), muscle cross-sectional area (29.1-35%), and failure strength of BTI (23.9-29.4%). Tensile test showed that the failure mode was avulsion of bone at the BTI. No significant difference was detected between TG and WBG for all assessments on bone, muscle, and BTI.

CONCLUSIONS

Disuse caused deterioration of bone, muscle, and BTI while daily short-duration of weight-bearing did not prevent this deterioration. Mechanical stimulation with higher intensity and longer duration may be necessary to prevent musculoskeletal deterioration resulted from prolonged disuse.

Cortical thinning and progressive cortical porosity in female patients with systemic lupus erythematosus on long-term glucocorticoids: a 2-year case-control study

In this study, we characterized longitudinal changes of volumetric bone mineral density and cortical and trabecular microstructure at the distal radius using HR-pQCT in female systemic lupus erythematosus (SLE) patients on long-term glucocorticoids. Cortical thinning and increased cortical porosity are the major features of longitudinal microstructural deterioration in SLE patients.

INTRODUCTION

The study aims to characterize longitudinal changes of volumetric bone mineral density (vBMD) and bone microstructure at distal radius in female systemic lupus erythematosus (SLE) patients on long-term glucocorticoids.

METHODS

This 2-year case-control study consisted of 166 premenopausal subjects (75 SLE patients and 91 controls) and 79 postmenopausal subjects (44 SLE patients and 35 controls). We obtained areal BMD (aBMD) by dual-energy X-ray absorptiometry at multiple skeletal sites and indices of vBMD and microstructure at distal radius by high-resolution peripheral quantitative computed tomography (HR-pQCT) at baseline, 12 and 24 months.

RESULTS

In either premenopausal or postmenopausal subjects, changes in aBMD did not differ between patients and controls except that decrease in aBMD at total hip at 24 months in premenopausal patients was significantly higher. In premenopausal subjects, decrease in cortical area (-0.51 vs. -0.06 %, p = 0.039) and thickness (-0.63 vs. 0.02 %, p = 0.031) and increase in cortical porosity (21.7 vs. 7.16 %, p = 0.030) over study period were significantly larger in patients after adjustment of age and body mass index. Decreased in trabecular vBMD was significantly less (-0.63 vs. -2.32 %, p = 0.001) with trabecular microstructure better maintained in patients. In postmenopausal subjects, decrease in cortical vBMD (-2.66 vs. -1.56 %, p = 0.039) and increase in cortical porosity (41.6 vs. 16.3 %, p = 0.021) were significantly higher in patients, and there was no group-wise difference in change of trabecular microstructure.

CONCLUSION

Longitudinal microstructural deterioration in SLE is characterized by cortical thinning and increased cortical porosity. Cortical bone is an important source of bone loss in SLE patients on glucocorticoids.

Development of biodegradable Zn-1X binary alloys with nutrient alloying elements Mg, Ca and Sr

Biodegradable metals have attracted considerable attentions in recent years. Besides the early launched biodegradable Mg and Fe metals, Zn, an essential element with osteogenic potential of human body, is regarded and studied as a new kind of potential biodegradable metal quite recently. Unfortunately, pure Zn is soft, brittle and has low mechanical strength in the practice, which needs further improvement in order to meet the clinical requirements. On the other hand, the widely used industrial Zn-based alloys usually contain biotoxic elements (for instance, ZA series contain toxic Al elements up to 40 wt.%), which subsequently bring up biosafety concerns. In the present work, novel Zn-1X binary alloys, with the addition of nutrition elements Mg, Ca and Sr were designed (cast, rolled and extruded Zn-1Mg, Zn-1Ca and Zn-1Sr). Their microstructure and mechanical property, degradation and in vitro and in vivo biocompatibility were studied systematically. The results demonstrated that the Zn-1X (Mg, Ca and Sr) alloys have profoundly modified the mechanical properties and biocompatibility of pure Zn. Zn-1X (Mg, Ca and Sr) alloys showed great potential for use in a new generation of biodegradable implants, opening up a new avenue in the area of biodegradable metals.

Comparative Efficacy of Four Treatments in Patients with Graves' Disease: a Network Meta-analysis

BACKGROUND

The question of which treatment should be preferred for the treatment of Graves' disease is debatable, and pairwise meta-analyses could not obtain hierarchies of these treatments. Our intention was to integrate the evidence to provide hierarchies of the comparative efficacy of 4 treatments (radioiodine, radioiodine+prednisone, antithyroid drugs and surgery).

METHODS

We conducted a Bayesian-framework network meta-analysis of randomized controlled trials (RCTs) to compare 4 treatments in patients with Graves' disease. The eligible RCTs were identified by searching Amed, the British Nursing Index, Embase, PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), Google scholar, SIGLE, the National Technical Information Service, the National Research Register (UK) and the Current Controlled Trials databases. The data for 2 outcomes (e.g., ophthalmopathy and recurrence) were independently extracted by 2 authors.

RESULTS

A total of 4 RCTs were ultimately included. Radioiodine+prednisone therapy showed statistical significance in reducing the incidence of new or deteriorative ophthalmopathy comparing with the other 3 therapies. Compared with radioiodine, therapy with antithyroid drugs therapy as well as surgery significantly decreased the incidence of new or deteriorative ophthalmopathy. Radioiodine therapy significantly reduced the rate of recurrence when compared to therapy with antithyroid drugs or surgery. For decreasing the incidence of new or deteriorative ophthalmopathy, the 4 treatments were ranked as follows: radioiodine+prednisone therapy, therapy with antithyroid drugs, surgery and radioiodine therapy. For reducing the rate of recurrence, 3 treatments were ranked as follows: radioiodine therapy, therapy with antithyroid drugs and surgery.

CONCLUSIONS

Radioiodine+prednisone therapy might have the least probability of leading to an exacerbation or new appearance of ophthalmopathy, and radioiodine therapy might have the least probability of causing a recurrence.

Heat Flow Analysis and Efficiency Optimization of Rotational Molding Equipment for Large Plastic Products

There exists an important relationship between the temperature fields and the heat utilization efficiency in the oven of rotational molding equipment. If the temperatures at the main locations can be reasonably controlled, then the efficiency of the rotational molding machine can be effectively improved. The main objective of this research project is to carry out numerical simulation and analysis of the velocity field and temperature field in the oven of a shuttle-type rotational molding machine by using the commercial code FLUENT. The machine was selected as the research object owing to its uneven temperature fields and large energy wastage. The simulation results were then verified by experiments. By improving the structure of the outlets of rotational molding machine and by reasonably controlling the temperature distribution in the oven and die, the working temperature can quickly reach the maximum point, and the uniformity of the temperature in the working area can be ensured. The results showed that the molding efficiency and energy efficiency of the rotational molding machine can be improved by controlling the temperature distribution, thereby increasing the production efficiency of rotational molding.

Acute restraint stress alters sound-evoked neural responses in the rat auditory cortex

Stress is known to elicit various adaptive or maladaptive responses in the nervous system function. Psychophysical studies have revealed that stress exposure induced the changes in auditory response that can be interpreted as a transient, stress-induced hypersensitivity to sounds. However, the underlying neural mechanism remains unresolved. Thus, in this study, we explored the neural activities of the auditory cortex (AC) in response to stress. We elicited stress by physically immobilizing rats and recorded the extracellular single-unit activities through the electrodes chronically implanted in the AC of rats. By comparing the spike activities of the same rat before, during and after immobilization, we found temporal and significant changes in the sound-evoked neural activities. In most cases, acute restraint stress enhanced neural responses evoked by pure-tones and click-trains, but in a minority of neurons, stress suppressed responses. The immobilization-induced enhancement was more frequently found in the neurons that originally had a low responsibility for sound stimuli. The enhancement effects on pure-tone response were reflected by an increase of response magnitude, decrease of response latency, and extension of bandwidth of tuning curve (BW). But the spontaneous firing rate and best frequency (BF) remained unchanged. Stress also increased the ability of neural response to synchronize to click-trains, even in the neurons whose response magnitude was not significantly increased. Taken together, these results provide direct evidence that stress alters the function of auditory system at the level of AC.

Effect of annealing temperature on the structure of carbon encapsulated Fe3O4 nanospheres

Yolk–shell structured Fe₃O₄@C was obtained at 600 °C. A possible evolution mechanism of core–shell to yolk–shell Fe₃O₄@C is elaborated.

Density, structure, and strength of the distal radius in patients with psoriatic arthritis: the role of inflammation and cardiovascular risk factors

We investigated the densitometric and microstructural features of the distal radius in psoriatic arthritis (PsA) patients using high-resolution peripheral quantitative computed tomography. PsA patients have unique bone microstructural deficits, manifested as lower cortical bone density and higher cortical porosity, which are associated with a propensity to bone fragility.

INTRODUCTION

The aim of this study was to investigate the densitometric, geometric, microstructural, and biomechanical features of the distal radius in psoriatic arthritis (PsA) patients.

METHODS

This study cohort consisted of 53 PsA patients (24 males and 29 females), with an average age of 53.1 years and 53 gender- and age-matched controls. Areal bone mineral density (aBMD) of the hip, lumbar spine, and ultradistal radius was measured by dual-energy X-ray absorptiometry. High-resolution peripheral quantitative computed tomography (HR-pQCT) was performed at the distal radius to obtain measures of volumetric BMD (vBMD), microstructure, and derived biomechanical indices.

RESULTS

There were no significant between-group differences in aBMD at the femoral neck, total hip, and ultradistal radius, while aBMD at the lumbar spine was significantly higher in patients. The only indices indicating compromised bone quality in PsA patients were related to cortical bone quality. Cortical vBMD were -3.8% significantly lower, while cortical pore volume, porosity index, and pore diameter were 108, 79.5, and 8.6%, respectively, significantly higher in patients. Cortical stress was marginally lower (-1.3%, p = 0.077) in patients with stress significantly more unevenly distributed (4.9%, p = 0.035). Endocortical perimeter and cortical pore volume were significantly higher in patients with vertebral fracture. Deficits in cortical bone quality were associated with indices of disease activity/severity and were more prominent in patients with type 2 diabetes mellitus or hypertension.

CONCLUSIONS

There is an intertwined relationship between chronic inflammation, cardiovascular risk factors, and bone loss in PsA. PsA patients seem to have unique bone microstructural deficits which are associated with a propensity to bone fragility.

De novo DNA methylation of the paternal genome in 2-cell mouse embryos

The developmental dynamics of DNA methylation events have been well studied. Active demethylation of the paternal genome occurs in the zygote, passive demethylation occurs during cleavage stages, and de novo methylation occurs by the blastocyst stage. It is believed that the paternal genome has lower levels of methylation during early development than the maternal genome. However, in this study, we provide direct and indirect evidence of genome-wide de novo DNA methylation of the paternal genome after the first cell cycle in mouse embryos. Although very little methylation was detected within the male pronucleus in zygotes, an intense methylation signal was clearly visible within the androgenetic 2-cell embryos. Moreover, the DNA methylation level of the paternal genome in the post-zygotic metaphase embryos was similar to that of the maternal genome. Using indirect immunofluorescence with an antibody to methylated lysine 9 in histone H3, we provided new evidence to support the concept of spatial compartmentalization of parental genomes in 2-cell mouse embryos. Nevertheless, the transient segregation of parental genomes was not observed by determining the DNA methylation distribution in the 2-cell embryos even though DNA methylation asymmetry between the maternal and paternal pronucleus existed in the 1-cell stage. The disappearance of separate immunofluorescence signals of 5-methyl cytosine in the 2-cell embryos might be attributed to the de novo methylation of the paternal genome during the first mitotic cycle.