Periodontal disease and myocardial infarction risk: A meta-analysis of cohort studies

IntroductionThe objective of this meta-analysis was to systematically assess the association between periodontal disease (PD) and myocardial infarction (MI).MethodsWe searched the EMBASE, PubMed, and Cochrane Library databases for eligible cohort studies from inception to August 31st, 2020 that reported the association between PD and MI. Data extraction was conducted after screening the literature. The risk of bias of the included studies was evaluated by using the Newcastle-Ottawa Scale (NOS). The combined OR value and 95% confidence interval (CI) were calculated by using STATA 11.0 software, and the source of any heterogeneity was determined by performing subgroup analysis and sensitivity analysis.ResultsA total of 10 cohort studies involving 5,369,235 participants fulfilled the inclusion criteria. The meta-analysis showed an increased risk for MI in patients with PD [RR = 1.13, 95% CI (1.04, 1.21), P = 0.004], and this result was robust according to sensitivity analysis. Subgroup analyses indicated that the results were affected by sex, effect value, study quality, survey form and investigation type.DiscussionThis meta-analysis suggests that PD is modestly associated with MI, especially in women, which is similar to the conclusions of earlier meta-analyses of case-control or observational studies. PD may be an untraditional risk factor for cardiovascular diseases, including MI; thus, maintaining periodontal health may be an effective measure to prevent MI. More cohort studies are still needed to further explore the relationship between the incidence of MI and PD.     

Mechanical properties and biocompatibility of melt processed,self-reinforced ultrahigh molecular weight polyethylene

The low efficiency of fabrication of ultrahigh molecular weight polyethylene (UHMWPE)-based artificial knee joint implants is a bottleneck problem because of its extremely high melt viscosity. We prepared melt processable UHMWPE (MP-UHMWPE) by addition of 9.8 wt% ultralow molecular weight polyethylene (ULMWPE) as a flow accelerator. More importantly, an intense shear flow was applied during injection molding of MP-UHMWPE, which on one hand, promoted the self-diffusion of UHMWPE chains, thus effectively reducing the structural defects; on the other hand, increased the overall crystallinity and induced the formation of self-reinforcing superstructure, i.e., interlocked shish-kebabs and oriented lamellae. Aside from the good biocompatibility, and the superior fatigue and wear resistance to the compression-molded UHMWPE, the injection-molded MP-UHMWPE exhibits a noteworthy enhancement in tensile properties and impact strength, where the yield strength increases to 46.3 ± 4.4 MPa with an increment of 128.0%, the ultimate tensile strength and Young's modulus rise remarkably up to 65.5 ± 5.0 MPa and 1248.7 ± 45.3 MPa, respectively, and the impact strength reaches 90.6 kJ/m². These results suggested such melt processed and self-reinforced UHMWPE parts hold a great application promise for use of knee joint implants, particularly for younger and more active patients. Our work sets up a new method to fabricate high-performance UHMWPE implants by tailoring the superstructure during thermoplastic processing.     

8周游泳运动对2型糖尿病大鼠周围神经病变的影响

 目的： 探讨长期游泳运动对2型糖尿病大鼠周围神经病变的影响及可能机制。方法: 雄性Wistar大鼠高糖高脂饲料喂养联合链脲佐菌素注射制备成T2DM大鼠模型后,随机分为空白对照组（C组）、单纯运动组（CE组）、糖尿病对照组（DM组）和糖尿病运动组（DME组）。CE组和DME组进行8周游泳训练（6 d/week）,第1周前3 d练习时间分别为20、30和45 min,第4天起每天持续游泳60 min。运动8周后测定各组大鼠坐骨神经的传导速度（MNCV）,以及该组织中肿瘤坏死因子α（TNF-α）、白细胞介素6（IL-6）、C反应蛋白（CRP）的含量,观察其形态结构。结果: 实验末,与DM组相比,DME组的MNCV明显提高（P<0.05）,坐骨神经组织中TNF-α、IL-6和CRP水平均有所降低,但差异无统计学意义（P>0.05）。DM组坐骨神经光镜下可见明显的损伤,经运动干预后病变程度减轻。结论: 8周游泳运动可提高MNCV,减轻DM造成的神经损伤,对周围神经起保护作用,其机制可能与减轻炎症反应有关。     

Short and long term analysis of heart rate variations in spontaneously hypertensive rats: effects of DSP-4 administration

The purpose of this study was to investigate whether or not central noradrenergic neurons were involved in the time structure of circadian variation of heart rate (HR) in hypertension. We used spontaneously hypertensive rats (SHR_Izm) and normotensive controls (Wistar Kyoto rats, WKY_Izm). We selectively destroyed the noradrenergic neurons in the central nervous system (CNS) by administering noradrenergic neurotoxin, N-(2-chloroethy)-N-ethyl-2-bromobenzylamine (DSP4). Frequency domain measures of variation of HR (VHR) were obtained using the maximum entropy method. The 24-h time frame in VHR is usually dominant in both SHR_Izm and WKY_Izm. Fourteen days after the administering of DSP4, the mean 24-h systolic arterial pressure (SAP) remained higher in SHR_Izm than in WKY_Izm. After chemical lesion, ultradian rhythms (12-, 8-, 6-, and 4-h periods) in VHR became more remarkable in both SHR_Izm and WKY_Izm than before chemical lesion. Before chemical lesion, an inverse relationship existed between frequency and power spectral density in VHR, demonstrating 1/f_β characteristics. The slope of 1/f_β in VHR did not differ between SHR_Izm and WKY_Izm. After the chemical lesion it did not also differ from that of each strain in control period (before lesion). Therefore, the noradrenergic neurons may not affect the time structure of HR in SHR_Izm and WKY_Izm for short-term time analysis. However, the intact noradrenergic neurons in CNS may be important to keep normal cardiac autonomic function in SHR_Izm for long-term analysis     

The utilization of decellularized tendon slices to provide an inductive microenvironment for the proliferation and tenogenic differentiation of stem cells

The extracellular matrix (ECM) microenvironment for the stem cell niches, including but not limited to the biochemical composition, matrix topography, and stiffness, is crucial to stem cell proliferation and differentiation. The purpose of this study was to explore the capacity of the decellularized tendon slices (DTSs) to induce stem cell proliferation and tenogenic differentiation. Rat adult stem cells, including tendon-derived stem cells (TDSCs) and bone marrow-derived stem cells (BMSCs), were identified to have universal stem cell characteristics. The DTSs were found to retain the native tendon ECM microenvironment cues, including the inherent surface topography, well-preserved tendon ECM biochemical composition and similar stiffness to native tendon. When the TDSCs and BMSCs were cultured on the DTSs respectively, the LIVE/DEAD assay, alamarBlue^® assay, scanning electron microscopy examination and qRT-PCR analysis demonstrated that the DTSs have the capacity to support these stem cells homogeneous distribution, alignment, significant proliferation and tenogenic differentiation. Taken together, the findings of this study indicate that the DTSs can provide a naturally inductive microenvironment for the proliferation and tenogenic differentiation of TDSCs and BMSCs, supporting the use of decellularized tendon ECM as a promising and valuable approach for tendon repair/reconstruction.     

大学生体质情况调查及影响因素分析

目的 调查成都体育学院400名大学生身体形态、身体机能、身体素质等多个方面的体质健康状况.方法 纳入2008～2010年成都体育学院的大一和大二学生的体质健康状况进行对比研究.包括男生234名和女生166名.测量身高、体重、肺活量、立定跳远、握力(男)、坐位体前屈(女)、台阶试验等7项指标.结果 成都体育学院学生的身体健康状况处于中等水平,情况良好,并且男生和女生平均身高体重水平优于全国水平.体育专业男生和女生的各项指标均高于非体育专业的学生.影响学生体质健康的因素主要有6种因素,其中参加体育锻炼的兴趣为主要因素.结论 学校应提高体育氛围从而确保每位学生每天有1h的体育活动时间,培养学生自身锻炼身体的意识和终生体育的理念.     

Effects of ethanol feeding and malnutrition on collagen synthesizing and degrading enzymes in rat pancreas

This study was performed to delineate the combined effects of a low-fat diet and chronic ethanol ingestion on collagen metabolism in rat pancreas. Rats fed a very low-fat diet (5% of total calories as lipid) for 12 weeks developed malnutrition as judged by weight loss (−33% of the initial body weight) and low serum albumin and amylase levels. The pancreas of malnourished rats showed increased collagenase activity with respect to animals fed a 35% lipid diet (p < 0.05). Hydroxyproline content was higher in the pancreas of malnourished rats and collagenase activity correlated well with hydroxyproline content (r = 0.57, p = 0.0013). Ethanol feeding for 12 weeks, regardless of the nutritional state of the rats, did not change the synthesis and degradation rates of collagen in the pancreas. The present study suggests that malnutrition may have profound effects on collagen metabolism.     

力竭运动性猝死模型大鼠运动皮质Bax、Bcl-2及脑源性神经营养 因子的表达变化

    文章快速阅读： 文题释义： 运动性猝死：是运动员或体育锻炼者在运动中或运动后24 h内,有症状或无症状情况下的意外死亡,运动负荷是诱发运动性猝死的主要因素之一,并且猝死的危险性随负荷强度增高而增大,大强度运动下运动性猝死的发生机制尚不清楚,分析大强度运动下出现的运动性猝死案例有助于探索其发生机制。 脑源性神经营养因子：是主要在中枢神经系统内表达的具有神经营养作用的蛋白质,它是一种脑组织细胞保护因子,在海马体和脑皮质内含量最高。力竭运动时大脑的相对缺血缺氧诱导发生了两个相反的级联过程,一个是由基因表达调控的神经元细胞主动性的死亡过程;另一个则是受到损伤刺激的神经元通过上调脑源性神经营养因子的表达水平而产生的一种主动性的细胞保护过程,从而使细胞能够抵御运动性脑缺血缺氧引起的病理生理损伤而得以存活。摘要 背景：运动性猝死是运动实践中的常见现象,因偶发故其机制不明。 目的：观察运动性猝死大鼠的运动皮质细胞形态学改变、凋亡调控因子Bax、Bcl-2及脑源性神经营养因子的表达变化,探讨连续力竭性负重游泳训练中运动性猝死的发生及调控机制。 方法：130只雄性SD大鼠随机选7只为空白对照组,其余大鼠在疲劳造模后按36 h的训练周期、对大鼠进行连续力竭性负重游泳训练,并分别在6×36 h、9×36 h与12×36 h训练后随机处死7只大鼠分别记为连续力竭性负重游泳训练1,2,3组(力竭运动1,2,3组);将多次相同模型实验中、6×36 h后偶然出现在每次训练中或训练后24 h内的死亡大鼠(排除因呛水死亡)记为运动性猝死组(n=5)。采用苏木精-伊红染色观察大脑运动皮质细胞的形态结构变化,免疫组织化学染色检测Bax、Bcl-2蛋白及脑源性神经营养因子的阳性表达变化。 结果与结论：①与空白对照组相比,力竭运动1,2,3组和运动性猝死组的运动皮质细胞形态结构发生明显改变,Bax、Bcl-2蛋白及脑源性神经营养因子的阳性表达率明显增高(P < 0.05);②在力竭运动1,2,3组和运动性猝死组中Bax及Bcl-2蛋白呈递增趋势,Bcl-2蛋白表达增强程度高于Bax蛋白;而脑源性神经营养因子的表达呈先增加后降低的趋势;③结果表明,力竭运动组及运动性猝死组中运动皮质细胞内Bax、Bcl-2蛋白及脑源性神经营养因子的阳性表达的增强可能与运动皮质细胞的保护抑制机制有关;过度疲劳时运动皮质内脑源性神经营养因子表达的下降可能是诱发运动性猝死的原因之一。 中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程 ORCID: 0000-0001-5187-9404(阳仁均)     

New prostaglandin analog formulation for glaucoma treatment containing cyclodextrins for improved stability,solubility and ocular tolerance

Latanoprost is a practically insoluble prostaglandin F2α analog considered a first-line agent for glaucoma treatment. From a pharmaceutical point of view, latanoprost is challenging to be formulated as an eye drop due to its poor water solubility and the presence of an ester bond that needs to be cleaved in vivo but maintained unchanged during storage. Cyclodextrins (CDs) are known to form complexes with hydrophobic drugs, influencing their stability, availability, solubility, and tolerance in a non-predictable manner. A variety of CDs including native α, β, and γCDs as well as substituted hydroxypropylβCD, hydroxypropylγCD, dimethylβCD, sulphatedβCD, and propylaminoβCD were screened and the most appropriate CD for the formulation of latanoprost for an ocular topical application was selected. Among the tested CDs, propylaminoβCD had the best trade-off between latanoprost stability and availability, which was confirmed by its complex constant value of 3129 M⁻¹. Phase-solubility and NMR investigations demonstrated that the propylaminoβCD effectively formed a complex involving the ester group of latanoprost providing protection to its ester bond, while ensuring proper latanoprost solubilization. Furthermore, in vivo experiments demonstrated that the latanoprost-propylaminoβCD formulation led to lower ocular irritation than the commercial latanoprost formulation used as a reference. The latanoprost-propylaminoβCD formulation was demonstrated to successfully address the main stability, solubility, and tolerance limitations of topical ocular latanoprost therapy for glaucoma.     

Influence of dual tasks on sitting postural sway in children and adolescents with myelomeningocele

Performing dual tasks, e.g. cognitive and motor tasks simultaneously, may be especially challenging to children with motor disorders. Changes in postural sway have been used to evaluate the effect of dual tasks. Increases in postural sway frequency and concurrent decrease in sway amplitude have been interpreted as tighter control of postural sway. The purpose of this study was to analyze postural sway under single and dual task conditions, while sitting. Thirteen children and adolescents with myelomeningocele and a matched control group were included in the study. The participants performed two single and two dual tasks each. The single task was a sitting still task. The dual tasks were one visual-spatial task and one executive task while simultaneously sitting still. Amplitude, velocity and frequency of center of pressure displacement of postural sway were analyzed between tasks and between groups. The results of the cognitive tasks were analyzed as well. The results revealed different patterns in the groups. During single tasks, the MMC group displayed significantly lower frequencies and velocities of center of pressure displacement compared to the control group. Adding the visual-spatial task influenced postural sway significantly in the control group, while adding the executive task influence the postural sway significantly in the MMC group. The myelomeningocele group confirmed our clinical experience by performing the cognitive tasks slowly but accurately. Further studies are needed to evaluate whether motor function, sensory function, structural anomalies in the brain or any other causes, separately or together, may explain the observed differences in the groups.