猪冠状动脉前降支结扎位点和左室功能的线性回归

目的探讨猪冠状动脉前降支(LAD)结扎百分位点和心梗体积、左室射血分数的关系,以期指导研究者能够根据急性心肌梗死模型的心功能要求选择合适的LAD结扎百分位点。方法将47只小型猪开胸结扎心脏LAD中远段约30%~75%的不同百分位点,分别于术前、术后1 h心脏超声检查左室射血分数(LVEF),术后3 d进行常规冠状动脉造影,4周处死测量前降支结扎位点和梗死体积,最后用简单直线回归模型分析LAD结扎百分位点和心梗体积、左室射血分数回归方程和相关系数。结果47例动物手术过程中死亡8只,剩余39只存活动物冠状动脉造影均显示LAD中远段结扎部位处完全闭塞,表明手术成功。LAD结扎百分位点和术后1 h LVEF、术后1 hLVEF下降值、梗死心肌体积均明显相关(相关系数r分别为0.87、0.78和0.90,P均<0.001),其回归方程分别为:术后LVEF(%)=65.88-0.55x结扎百分位点;术后LVEF下降值(%)=0.12 0.59x结扎百分位点;心肌梗死体积(%)=0.53x结扎百分位点-5.43。结论猪LAD结扎百分位点和术后左室功能、梗死心肌体积均存在显著的相关性,可根据实验目的和对心功能的要求选择合适的结扎百分位点。     

Deregulation of allosteric response of Lactococcus lactis prolidase and its effects on enzyme activity

The allosteric behaviour of Lactococcus lactis prolidase (Xaa-Pro dipeptidase) of this proline-specific peptidase was investigated where it was hypothesized that intersubunit interactions between a loop structure and three residues near the active site contributed to this behaviour. Seven mutant prolidases were constructed, and it was observed that the loopless mutant and His303 substitution inactivated the enzyme. Ser307 substitution revealed that this residue influenced the substrate binding, as judged from its kinetic constants and substrate specificity; however, this residue did not contribute to allostery of prolidase. R293S mutation resulted in the disappearance of the allosteric behaviour yielding a Hill constant of 0.98 while the wild type had a constant of 1.58. In addition, the R293S mutation suppressed the substrate inhibition that was observed in other mutants and wild type. The K_m value of R293S was 2.9-fold larger and V_max was approximately 50% less as compared to the wild type. The results indicated that Arg293 increased the affinity for substrates while introducing allosteric behaviour and substrate inhibition. Computer modelling suggested that negative charges on the loop structure interacted with Arg293 and Ser307 to maintain these characteristics. It was, therefore, concluded that Arg293, His303, Ser307 and the loop contributed to the enzyme's allosteric characteristics.     

Decreases in Both the Seroprevalence of Serum Antibodies and Seroprotection against Japanese Encephalitis Virus among Vaccinated Children

The incidence of Japanese encephalitis(JE) has significantly decreased in China due to JE vaccines. In this study, we investigated the post-JE vaccination seroprevalence and protection provided by vaccinated sera against Japanese encephalitis virus(JEV) to elucidate the persistence and waning of antibodies to JEV among JE-SA14-14-2-vaccinated children. A total of 300 serum samples were collected from vaccinated children aged 3–10 years in Zhaotong, Yunnan,China. The seroprevalence of anti-JEV antibodies was determined by enzyme-linked immune sorbent assay and plaque reduction neutralization test. The highest seropositivity of 82% was observed in vaccinated children during the first0.5–1.5 years after booster vaccination. Then, the seropositivity began to decline and remained lower than the original level observed in the 0.5–1.5-year group. An association was found between the waning of seroprevalence and elapsed time of the post-booster vaccination. Similarly, the neutralizing antibody(nAb) titres gradually decreased over time, and the levels showed a positive correlation with the protective efficacy in mice. This finding suggests that nAbs play an important role in the antiviral process and that the nAb titre is an adequately credible parameter for evaluating the protective efficacy induced by the JE vaccine. Our results provide data that clarify the persistence and waning of antibodies to JEV, which may help elucidate the pathogenesis of JE.     

Perivascular adipose tissue‐derived stromal cells contribute to vascular remodeling during aging

Aging is an independent risk factor for vascular diseases. Perivascular adipose tissue (PVAT), an active component of the vasculature, contributes to vascular dysfunction during aging. Identification of underlying cell types and their changes during aging may provide meaningful insights regarding the clinical relevance of aging‐related vascular diseases. Here, we take advantage of single‐cell RNA sequence to characterize the resident stromal cells in the PVAT (PVASCs) and identified different clusters between young and aged PVASCs. Bioinformatics analysis revealed decreased endothelial and brown adipogenic differentiation capacities of PVASCs during aging, which contributed to neointimal hyperplasia after perivascular delivery to ligated carotid arteries. Mechanistically, in vitro and in vivo studies both suggested that aging‐induced loss of peroxisome proliferator‐activated receptor‐γ coactivator‐1 α (PGC1α) was a key regulator of decreased brown adipogenic differentiation in senescent PVASCs. We further demonstrated the existence of human PVASCs (hPVASCs) and overexpression of PGC1α improved hPVASC delivery‐induced vascular remodeling. Our finding emphasizes that differentiation capacities of PVASCs alter during aging and loss of PGC1α in aged PVASCs contributes to vascular remodeling via decreased brown adipogenic differentiation.     

气候变化和经济发展对肾综合征出血热发生的影响

肾综合征出血热(hemorrhagic fever with renal syndrome, HFRS)是一种啮齿动物传播的自然疫源性疾病, 危害严重, 已成为全球重要的公共卫生问题。本研究采用数理统计模型及小波分析方法, 对陕西省西安市鄠邑区1984-2016年HFRS的发生与鼠类、气候和经济因素的关系进行分析, 探讨气候和经济因素对HFRS发生的影响。小波分析结果表明, 该地区的HFRS暴发史可能分为两个时期, 推测每个时期具有不同的主要宿主, 在2002年褐家鼠(Rattus norvegicus)可能取代黑线姬鼠(Apodemus agrarius)成为HFRS疫源地的主要宿主。广义可加模型模拟结果表明, HFRS的发生与1984-2001年黑线姬鼠密度间存在极显著非线性效应(F_2.06,9.02 = 102.415, P < 0.01), 两者间显现为正相关; 与2002-2016年的褐家鼠密度间呈正相关(F_1.67,9.02 = 73.929, P < 0.01); HFRS主要宿主的这种变化可能与当地气候变化和经济发展有关: HFRS的发生与年平均温度存在极显著的非线性效应(F_2.93,9.02 = 12.164, P < 0.01), 两者间呈负相关; 同样, HFRS的发生与上一年的国内生产总值(GDP)也存在显著非线性效应(F_1.70,9.02 = 2.917, P < 0.05), 两者间也呈负相关。结构方程模型通过直接和间接的影响途径证明了这种转移机制, 发现温度对HFRS发生有显著的直接负向影响以及通过褐家鼠的间接正向影响; GDP对HFRS发生有直接的负向影响。本研究表明HFRS的发生与气候变化和经济发展相关, 两者均能影响HFRS的暴发, 该结论有助于今后更好地对HFRS疾病进行预防和控制。     

Influences of Environmental Factors on Leaf Morphology of Chinese Jujubes

Rainfall and temperature are the primary limiting factors for optimum quality and yield of cultivated jujube (Ziziphus jujuba Mill.). Adaptation to arid and cool environments has been and remains an important goal of many jujube improvement programs. This study summarized the survey results of 116 Chinese jujube varieties grown at 33 sites in China. The objective was to identify the environmental factors that influence leaf morphology, and the implications for breeding and introduction of new jujube varieties. Jujube leaf morphological traits were evaluated for their potential relationships with mean annual temperature (MAT) and mean annual precipitation (MAP). The results showed that many leaf morphological traits had a strong linear relationship with local precipitation and temperature. Longer veins per unit area (VLA) and reduced leaf area and leaf perimeter were typical of arid areas. VLA was inversely related to MAT and MAP at the centers of origin of jujube. There was a positive relationship between leaf shape (perimeter²/area) and both MAT and MAP. These results indicated that leaf vein traits of Chinese jujubes might have resulted from their adaptation to environmental factors in the course of long-term evolution. Principal component analysis allocated the 116 jujube varieties to three different groups, differentiated on the basis of morphological and physiological leaf characteristics. Jujube varieties from the Hebei, Shandong, Henan, southern Shanxi and central Shaanxi provinces were closely related, as were varieties from northwest Shanxi and northeast Shaanxi provinces, and varieties from the Gansu and Ningxia provinces. These close relationships were partially attributed to the frequent exchanges of varieties within each group. Leaf venation characteristics might be used as reference indices for jujube variety introduction between different locations.Influences of Environmental Factors on Leaf Morphology of Chinese Jujubes     

The effects of proteasome inhibitor lactacystin on mouse oocyte meiosis and first cleavage

Many studies have shown that the ubiq-uitin-proteasome pathway (UPP) for the degradation of short-lived proteins plays a key role in regulating cell cycle progression[1—3]. At least two distinct prote-olytic pathways are required for cell cycle process. The first pathway promotes transition from G1 to S phase, and the second initiates the onset of anaphase and exit from mitosis. The inhibition of UPP will re-sult in the blockage of cell cycle process. The knowl-edge of the role of UPP in…     

皂荚皂甙提取工艺的研究

研究了以皂荚为原料,对传统有机溶剂提取与水提取和超临界CO2萃取三萜皂甙进行了比较,得出水最适合提取皂荚皂甙;水提工艺部分,在单因素实验的基础上采用正交设计实验优化工艺,得出提取皂荚皂甙的最佳工艺。     

大别山区黑沟绿太阳鱼种群的形态特征研究

绿太阳鱼是2015年4月在大别山区淠河流域支流中新发现的入侵鱼类。利用2015年7月从黑沟中采集的78尾绿太阳鱼标本,对该物种的形态特征进行了详细测量和分析。结果发现绿太阳鱼种群内的形态相似性较高,但还存在一定的形态差异。相比性别,年龄是造成这种形态差异的主要原因。雄性从Ⅰ龄开始出现显著的形态分化,而雌性差异并不显著。这种形态学的差异完全符合雄鱼筑巢护卵的习性,具体表现在雄鱼头部指标（D1-2、D2-3、眼间距、眼后头长、头长）、臀鳍附近指标（D5-7、D5-8）、背鳍基部指标（D6-8）和尾柄处指标（D9-10）增大。同时相比Ⅰ龄以上的雄鱼,雌鱼和0龄雄鱼的尾柄指标（D8-10、D8-9）较长,身体更适于流水环境。这种雌雄体型上的变化,将有助于雄鱼占领溪流环境中的静水区（深潭）,而雌鱼和0龄鱼占领流水区（急滩、湍流）,这为该种群适应山区溪流的水文环境,合理分配生态位提供了便利条件,同时也使其对大别山区其他鱼类具有较大的生态危害潜力。