Reaction Kinetics and Thermodynamic Aspects of Thermoreversibly Cross‐Linked Polymer Networks

The Diels–Alder reaction of furan and maleimide is used to prepare reversibly cross‐linking polymer gels consisting of furan‐bearing polymer chains and bismaleimides. The roles of chain length, stoichiometry, and concentration on gelation kinetics and other properties are evaluated. Additionally, kinetics of the Diels–Alder reactions in the gelling system are compared with the kinetics of small molecule systems. By combining spectroscopic and rheological techniques, a mechanochemical analysis is performed.

     

星点设计-效应面法优化白鲜皮多糖硫酸酯化工艺及抗氧化活性

目的 利用星点设计-效应面法优化白鲜皮多糖（Dictamnus dasycarpus polysaccharide,DDP）硫酸酯化工艺,考察DDP修饰前后结构特征及抗氧化活性。方法 采用氯磺酸-吡啶法,以酯化试剂比例、酯化试剂与多糖溶液比例、反应温度、反应时间为自变量,硫酸根取代度（degree of substitution,DS）为因变量,对自变量各水平进行多元回归拟合,利用效应面法筛选最佳工艺并进行预测分析;采用红外光谱及扫描电镜观察其结构特点。测定硫酸酯化白鲜皮多糖（sulfated polysaccharides from Dictamnus dasycarpus,SDDP）对DPPH、OH·、O₂^-·清除能力,考察其抗氧化活性。结果 最佳工艺条件为酯化试剂比例1：4,酯化试剂与多糖溶液比例1：1,反应温度73℃,反应时间5 h。红外光谱显示SDDP在820 cm^-1和1 254 cm^-1附近出现C-O-S和S=O硫酸基特征吸收峰,表明DDP修饰成功;扫描电镜显示SDDP表面粗糙,排列紧密,且块状体积明显小于DDP;DDP和SDDP都有清除DPPH、OH·和O₂^-·能力,且SDDP对DPPH、OH·和O₂^-·清除率强于DDP。结论 星点设计-效应面法优化DDP硫酸酯化工艺方法简便且预测性良好,DDP经硫酸酯化后,抗氧化活性有所提高。     

High triglyceride-glucose index is associated with adverse cardiovascular outcomes in patients with acute myocardial infarction

Background and aimsTriglyceride glucose (TyG) index is considered a new surrogate marker of insulin resistance that associated with the development of vascular disease. The aim of this study was to evaluate the prognostic value of TyG index in patients with acute myocardial infarction (AMI).Methods and resultsA total of 3181 patients with AMI were included in the analysis. Patients were stratified into 2 groups according to their TyG index levels: the TyG index <8.88 group and the TyG index ≥8.88 group. The incidence of major adverse cardiovascular events (MACEs) during a median of 33.3-month follow-up were recorded. Multivariable Cox regression models revealed that the TyG index was positively associated with all-cause death [HR (95% CI): 1.51 (1.10,2.06), p = 0.010], cardiac death [HR (95% CI): 1.68 (1.19,2.38), p = 0.004], revascularization [HR (95% CI): 1.50 (1.16,1.94), p = 0.002], cardiac rehospitalization [HR (95% CI): 1.25 (1.05,1.49), p = 0.012], and composite MACEs [HR (95% CI): 1.19 (1.01,1.41), p = 0.046] in patients with AMI. The independent predictive effect of TyG index on composite MACEs was mainly reflected in the subgroups of male gender and smoker. The area under the curve (AUC) of the TyG index predicting the occurrence of MACEs in AMI patients was 0.602 [95% CI 0.580,0.623; p < 0.001].ConclusionHigh TyG index levels appeared to be associated with an increased risk of MACEs in patients with AMI. The TyG index might be a valid predictor of cardiovascular outcomes of patients with AMI.Trial registrationRetrospectively registered.     

Repeated Baclofen treatment ameliorates motor dysfunction,suppresses reflex activity and decreases the expression of signaling proteins in reticular nuclei and lumbar motoneurons after spinal trauma in rats

The interruption of supraspinal input to the spinal cord leads to motor dysfunction and the development of spasticity. Clinical studies have shown that Baclofen (a GABA_B agonist), while effective in modulating spasticity is associated with side-effects and the development of tolerance. The aim of the present study was to assess if discontinued Baclofen treatment and its repeated application leads antispasticity effects, and whether such changes affect neuronal nitric oxide synthase (nNOS) in the brainstem, nNOS and parvalbumin (PV) in lumbar α-motoneurons and glial fibrillary acidic protein in the ventral horn of the spinal cord. Adult male Wistar rats were exposed to Th9 spinal cord transection. Baclofen (30 mg/b.w.) diluted in drinking water, was administered for 6 days, starting at week 1 after injury and then repeated till week 4 after injury. The behavior of the animals was tested (tail-flick test, BBB locomotor score) from 1 to 8 weeks. Our results clearly indicate the role of nitric oxide, produced by nNOS in the initiation and the maintenance of spasticity states 1, 6 and 8 weeks after spinal trauma. A considerable decrease of nNOS staining after Baclofen treatment correlates with improvement of motor dysfunction. The findings also show that parvalbumin and astrocytes participate in the regulation of ion concentrations in the sub-acute phase after the injury.     

血清趋化素水平与代谢综合征的相关性研究

目的 探讨血清趋化素（Chemerin）水平与MS的相关性. 方法 选取非MS（Non-MS）组57例,MS组117例及健康对照（NC）组90名,按Chemerin水平从低到高分为Ter1、Ter2和Ter3亚组.所有研究对象行75 g OGTT和胰岛素释放试验,检测血脂、血清Chemerin、高敏C反应蛋白（hsC-RP）等相关生化指标. 结果 MS组血清Chemerin水平高于Non-MS组和NC组（P＜0.01）.从Ter1到Ter3亚组,BMI、WC、WHR、SBP、FPG、2 hPG、HbA1 c、FIns、HOMA-IR、TG、hsC-RP水平依次升高,HDL-C水平依次降低,MS的患病率依次增加（P＜0.05）.Chemerin与BMI、WC、WHR、SBP、FPG、2 hPG、HbA1 c、FIns、2 hIns、HOMA-IR、TG及hsC-RP呈正相关（P＜0.05）,与HDL-C、胰岛β细胞功能指数（HOMA-β）呈负相关（P＜0.01）.Logistic逐步回归分析显示,Chemerin是MS的独立危险因素（OR=2.197,P＜0.01）.受试者工作曲线（ROC）曲线提示Chemerin预测MS的界值为72.4 ng/ml.结论 Chemerin与MS的发生相关,可作为MS的独立预测指标之一.     

Takotsubo cardiomyopathy has a unique cardiac biomarker profile: NT-proBNP/myoglobin and NT-proBNP/troponin T ratios for the differential diagnosis of acute coronary syndromes and stress induced cardiomyopathy

Background

Takotsubo cardiomyopathy (TC) usually is not recognized until heart catheterization reveals typical wall motion abnormalities in the absence of significant coronary artery disease. It was our aim to identify TC by its unique cardiac biomarker profile at an early stage and, preferably, with non-invasive procedures only.

Methods

Ratios of N-terminal prohormone of brain natriuretic peptide (NT-proBNP) and myoglobin, NT-proBNP and troponin T (TnT), NT-proBNP and creatinekinase-MB (CK-MB) were compared in patients with TC (n = 39), patients with ST-elevation myocardial infarction (STEMI, n = 48) and patients with non-ST-elevation myocardial infarction (NSTEMI, n = 34). Biomarkers were recorded serially at admission and at the three consecutive days. Optimal cut-off values to distinguish TC from STEMI and NSTEMI were calculated with receiver operator characteristic (ROC) curves.

Results

At admission a NT-proBNP (ng/l)/myoglobin (μg/l) ratio of 3.8, distinguished TC from STEMI (sensitivity: 89%, specificity: 90%), while a NT-proBNP (ng/l)/myoglobin (μg/l) ratio of 14 separated well between TC and NSTEMI (sensitivity: 65%, specificity: 90%). Best differentiation of TC and ACS was possible with the ratio of peak levels of NT-proBNP (ng/l)/TnT (μg/l). A cut-off value of NT-proBNP (ng/l)/TnT (μg/l) ratio of 2889, distinguished TC from STEMI (sensitivity: 91%, specificity: 95%), while a NT-proBNP (ng/l)/TnT (μg/l) ratio of 5000 separated well between TC and NSTEMI (sensitivity: 83%, specificity: 95%).

Conclusions

TC goes along with a singular cardiac biomarker profile, which might be useful to identify patients with TC among patients presenting with acute coronary syndromes (ACS).     

mTOR inhibition with rapamycin causes impaired insulin signalling and glucose uptake in human subcutaneous and omental adipocytes

Rapamycin is an immunosuppressive agent used after organ transplantation, but its molecular effects on glucose metabolism needs further evaluation. We explored rapamycin effects on glucose uptake and insulin signalling proteins in adipocytes obtained via subcutaneous (n=62) and omental (n=10) fat biopsies in human donors. At therapeutic concentration (0.01 μM) rapamycin reduced basal and insulin-stimulated glucose uptake by 20-30%, after short-term (15 min) or long-term (20 h) culture of subcutaneous (n=23 and n=10) and omental adipocytes (n=6 and n=7). Rapamycin reduced PKB Ser473 and AS160 Thr642 phosphorylation, and IRS2 protein levels in subcutaneous adipocytes. Additionally, it reduced mTOR-raptor, mTOR-rictor and mTOR-Sin1 interactions, suggesting decreased mTORC1 and mTORC2 formation. Rapamycin also reduced IR Tyr1146 and IRS1 Ser307/Ser616/Ser636 phosphorylation, whereas no effects were observed on the insulin stimulated IRS1-Tyr and TSC2 Thr1462 phosphorylation. This is the first study to show that rapamycin reduces glucose uptake in human adipocytes through impaired insulin signalling and this may contribute to the development of insulin resistance associated with rapamycin therapy.     

Localization of masticatory motoneurons in the trigeminal motor nucleus of shrew and pig,with emphasis on the innervation ratio in the shrew

Objectives:We investigated the topographical representation of the masticatory muscles, primarily in the trigeminal motor nucleus (TMN) of the house musk shrew (Suncus murinus) and miniature pig, in a series of mammalian comparative anatomical studies. Additionally, correlations between motoneurons and muscles were investigated in order to examine the functionality of each muscle in the trigeminal motor system.Methods:Motoneurons were labeled using horseradish peroxidase (HRP) injection into each muscle innervated by the trigeminal nerve. In the shrew, the sizes and numbers of HRP-labeled neurons, muscle weight, and numbers of muscle fibers were measured in the innervated muscles, and correlation coefficients for the relationships among these parameters were calculated.Results:The motoneuron cluster of each muscle was arranged in the TMN in a manner similar to that observed in other previously reported animals, but the distribution of the lateral pterygoid motoneurons varied between species. In addition, considerably higher overlap was observed in each pig jaw-closer motoneuron cluster compared with other animals. The approximate innervation ratios were as follows: masseter, 337; temporal, 322; anterior digastric, 137; medial pterygoid, 110; lateral pterygoid, 79; mylohyoid, 42; tensor veli palatini, 42; transverse mandibular, 16; and tensor tympani muscles, 5.ConclusionsThe distribution pattern of the masticatory motoneurons was clearly observed in the shrew and pig TMN, and various correlations between the motoneuron and innervated muscles were determined.