静注甘遂提取液对大白鼠肠系膜微循环机能的影响

甘遂是一种峻下逐水的中药。现以其较好的效果应用于临床中期妊娠引产。为了探讨甘遂的引产机制,实验以大白鼠为对象,观察了静注甘遂提取液对大白鼠肠系膜微循环机能的影响。结果显示:甘遂提取液可使大白鼠肠系膜微动脉显著收缩,持续时间较长;微循环血流减慢,重者停止;血液流态显著异常,轻者红细胞聚集,重者血液混化以至凝血。文中并对甘遂的引产机理进行了初步分析。     

甘遂半夏汤中甘遂甘草反药组合加减应用的急性毒性研究

 通过急性毒性实验比较甘遂半夏汤、甘遂半夏汤去炙甘草、甘遂半夏汤去醋甘遂、甘遂半夏汤去炙甘草醋甘遂、炙甘草、醋甘遂、炙甘草配醋甘遂毒性的大小。将18~20g的昆明小鼠随机分为空白组、甘遂半夏汤组、甘遂半夏汤去炙甘草组、甘遂半夏汤去醋甘遂组、甘遂半夏汤去炙甘草醋甘遂组、炙甘草组、醋甘遂组、炙甘草配醋甘遂组,空白组灌胃蒸馏水,其余各组灌胃给药,各组在均未做出LD₅₀的情况下,采用连续给药28d,即累计半数致死量的方法来进行毒性大小的评价。结果显示,炙甘草配醋甘遂组、炙甘草组及甘遂半夏汤组LD_50(n)的值分别为44.21、48.26、51.01g生药·kg^-1,其余各组连续给药28d仍未达到半数致死量。由此表明,甘遂半夏汤去掉方中甘遂甘草反药组合中的一味或两味没有显示出蓄积毒性,两味反药组合在复方中应用其LD_50(n)值有增加趋势。     

甘遂半夏汤中甘遂与甘草不同比例配伍对癌性腹水模型大鼠肝功能的影响

 通过甘遂与甘草不同比例配伍的甘遂半夏汤对腹水模型大鼠肝功能相关指标的检测,筛选甘遂与甘草反药组合对肝毒性影响的配比宜忌条件。将甘遂与甘草按照2因素7水平的均匀设计实验原则设置不同配伍比例,观察甘遂与甘草不同配比的甘遂半夏汤对癌性腹水模型大鼠血清转氨酶、总蛋白(TB)、白蛋白(ALB)、球蛋白(GLB)及肝组织病理形态的影响,并利用中药组方优化软件对生物效应指标进行甘遂与甘草配比的优化分析。研究表明,配比1组(10.40﹕1.17)和配比6组(20.80:0.78)较模型组显著降低谷草转氨酶(AST)水平(P < 0.05);配比4组(3.47:0.39)较模型组显著增加谷丙转氨酶(ALT)、ALB水平(P < 0.05);配比5组(0.21:1.56)、配比7组(17.34:1.94)及呋塞米组较模型组显著降低ALT水平;但各给药组AST/ALT与模型组无显著性差异(P > 0.05);病理形态变化显示,配比2组(6.94:2.33)、配比5组(0.21:1.56)、配比7组(17.34:1.94)及呋塞米组较模型组病变程度重。结果显示,甘遂用量在1.5g以上的配比组,肝细胞组织结构损伤较其他给药组严重,提示配比组的肝损伤作用可能与甘遂用量过大有关。     

猫免疫缺陷综合症的实验研究

<正> 作者描述了具有强烈免疫抑制作用的一株猫白血病病毒(FeLV)的鉴定、实验性感染及致病特性。该毒株从一只自然感染猫白血病病毒的猫胸腺淋巴瘤组织中分离得到。作者称之为猫白血病—艾滋病病毒(FeLVFAIDS)。25只SPF猫经鼻腔、腹腔接种这种病毒后,都能产生持续性的病毒血症及致死性和获得性免疫缺陷综合症(AIDS)。由于接种时猫年龄的不同,可发生急性免疫缺陷综合症和慢性免疫缺陷综合症。前者的接种后存活时间在3月以下,多发生于8周龄以下的猫,后者的存活时间在一年以上,多发生于15周龄以上的猫。猫白血病—艾滋病病毒诱发的免疫缺陷综合症有如下特征:接种后有一个无症状的病毒血症时期;体重逐渐下降;当淋巴组织的淋巴小结增生时,病毒     

会吐丝的猫

<正>南美洲有一种奇特的猫,它能像蚕一样地吐出丝来,所以人们叫它蚕猫。蚕猫的口中有两对吐丝孔,当吐丝孔内积满黏液后蚕猫就开始吐丝。它每年吐丝两次,吐丝前两     

猫肾上皮细胞的制备与研究

<正> 1983年至1986年,西安市和兰州市流行着一种以发热、呕吐、腹泻、白细胞减少为特征的猫病,疑似为猫泛白细胞减少症病毒所致,为了分离、培养和研究该病毒,我们采取了不同的方法对猫肾上皮原代细胞及其继代细胞的制备进行了研究,成功地制出猫肾上皮原代和继代细胞,现将制备方法和体会报告如下。     

猫传染性腹膜炎的诊断

目的对临床疑似猫传染性腹膜炎病例进行分子生物学、病理学诊断。方法根据冠状病毒3'UTR保守基因序列设计一对引物,对4例病死猫的组织器官和10例腹水进行RT-PCR检测,并对扩增产物进行序列测定;同时对所有病死猫组织器官进行组织病理学诊断。结果RT-PCR扩增产物克隆测序结果与GenBank中猫传染性腹膜炎病毒基因序列同源性为97%~98%。小肠浆膜、肝脏、脾脏等组织可观察到典型的炎性肉芽肿样变、灶性坏死和炎性细胞浸润。结论证实了4只病死猫感染了猫传染性腹膜炎病毒,且10例腹水中检测到猫传染性腹膜炎病毒核酸。     

猫

<正>我们家没有正儿八经地养过猫。家里的猫,都是从后山上跑下来的地地道道的野猫。最初有猫在我们家院子里溜达的时候,是两三年前。那是一只黑背白肚子的猫,有一对翡翠色的大眼睛,喜欢在竹林中那块空地上趴着晒太阳。6我放学回到家,总要往竹林中扫一眼,看看有没有那只猫的踪影。我向来是很喜欢猫的,觉得猫是一种很有灵性的动物,看见猫就     

桉树林里的怪声

<正>夕阳落下,夜色渐渐笼罩大地。好奇猫在一片桉树林旁边搭好帐篷,躺了进去。一连几天旅行让好奇猫疲惫不堪,他刚躺下就睡着了。迷迷糊糊间,一阵咔咔声传到他的耳畔。被吵醒的好奇猫侧耳细听,发现声音从桉树林里传出来,立即警觉起来。难道有动物偷偷砍伐桉树？好奇猫是环保主义者,容不得偷偷砍伐树木的事发生。他打开手电筒,钻出帐篷,走进桉树林,想制止偷伐者。     

世界真奇妙,这些有趣的科学发现

<正>01神秘猫狐生活在科西嘉岛上的神秘“猫狐”,最近在科学界终于有了身份!猫狐被当地人称为“ghjattu volpe”,也就是猫狐的意思。几百年前,人们就知道它们的存在了。在牧羊人代代相传的神话中,它们是神出鬼没的恶霸,会在半夜偷袭羊圈。但一直没人记录下它们的庐山真面目,因此它们在科学上的真实身份也是一个谜团。     

舞龙舞狮运动在部队开展的可行性研究——以湖南邵阳62158部队为例

本文运用文献资料法、专家访谈法,对62158部队开展舞龙舞狮运动的可行性进行了研究。结果表明：舞龙舞狮运动是一项非常优秀的民族传统体育项目,舞龙舞狮运动进入62158部队是现代竞技体育和中华民族传统体育项目的结合,有利于62158部队文艺活动的开展和传统文化传播的进一步深化,对弘扬中华民族传统文化,振奋民族精神,促进龙狮运动的普及与提高具有十分重要的意义。     

地面上物体的机械能呼吸效应

机械能流学说分析太阳坐标系中地球表面上物体的机械能的昼夜变化,用简述机械能呼吸效应,指出它应是导致地壳构造运动的主要力源之一。     

Large-scale forest girdling shows that current photosynthesis drives soil respiration.

The respiratory activities of plant roots, of their mycorrhizal fungi and of the free-living microbial heterotrophs (decomposers) in soils are significant components of the global carbon balance, but their relative contributions remain uncertain. To separate mycorrhizal root respiration from heterotrophic respiration in aboreal pine forest, we conducted a large-scale tree-girdling experiment, comprising 9 plots each containing about 120 trees. Tree-girdling involves stripping the stem bark to the depth of the current xylem at breast height terminating the supply of current photosynthates to roots and their mycorrhizal fungi without physically disturbing the delicate root-microbe-soil system. Here we report that girdling reduced soil respiration within 1-2 months by about 54% relative to respiration on ungirdled control plots, and that decreases of up to 37% were detected within 5 days. These values clearly show that the flux of current assimilates to roots is a key driver of soil respiration; they are conservative estimates of root respiration, however, because girdling increased the use of starch reserves in the roots. Our results indicate that models of soil respiration should incorporate measures of photosynthesis and of seasonal patterns of photosynthate allocation to roots.     

Variation characteristics of soil respiration fluxes in four types of grassland communities under different precipitation intensity

In the global carbon cycle studies, terrestrial ecosys- tem has become one of the greatest uncertain ecosystems in the current carbon cycle studies owing to the complex- ity of its underlying surface and intense disturbance of anthropogenic activities[1], hence depth studies of it serveas a key in seeking for the “missing carbon sinks” of at-mosphere. In the terrestrial ecosystem, soil organic carbonreservoir is an important component of carbon reservoir inthe system, its carbon …     

人体呼吸动力过程仿真研究

人体呼吸动力过程的呼吸参数和动态变化影响和决定了与人体呼吸领域相关设备的研制和参数设定。根据人体呼吸的运动规律,构建呼吸动力方程,进而利用仿真手段模拟人体呼吸动力过程,获得呼吸过程中的肺容积、呼吸流率和呼吸时间等动态呼吸参数。与以往的研究和实测数据验证比较,仿真过程和获得的数据更加贴近人体的实际呼吸运动过程,并且设置了更为详尽且独立的影响呼吸动力过程的参数,给出了易于理解的仿真框架。呼吸肌作用力方程和仿真获得的动态呼吸参数可用于人体模拟肺、供氧系统和辅助呼吸装置等设备的设计和参数设定。     

哀牢山中山湿性常绿阔叶林3种主要树种树干呼吸特征

森林生态系统是陆地生态系统中最重要的组成部分之一,是一个重要的碳库,树干呼吸是森林碳平衡的重要组成部分.为了研究哀牢山中山湿性常绿阔叶林的树干呼吸日变化和季节变化规律,以及它们与影响因子的关系,采用CO2红外气体分析法(IRGA),对哀牢山中山湿性常绿阔叶林3种主要树种(变色锥、黄心树和南洋木荷)的树干呼吸进行为期1a活体原位监测,还监测了干季(4月)和雨季(8月)黄心树和南洋木荷的树干呼吸日变化特征.研究发现,2个树种的树干呼吸、树干温度和空气温度日变化幅度并不大,3种树种的树干呼吸具有相同的季节规律,并且雨季的树干呼吸速率大于干季;不同树种以及同一树种不同径阶对温度的响应不一致;3种树种树干呼吸速率与胸径呈显著的正相关关系(R2=0.216).     

刺激家兔小脑顶核对动脉血压和呼吸的影响

实验用家兔３７只，戊巴比妥钠麻醉，自然呼吸，其中２７只采用电刺激小脑项核，１０只为顶核内微量注射神经元胞体兴奋剂（Ｌ－谷氨酸钠）．观察到电刺激小脑顶核能引起动脉血压显著升高，但心电图记录无明显变化；呼吸运动明显加深加快，肺通气量显著增加．而项核内微量注射Ｌ－谷氨酸钠．则出现动脉血压降低，心率无明显变化，呼吸也无显著性变化．提示顶核神经元兴奋产全降压作用，而电刺激所致的升压和呼吸反应可能与顶核周围的神经纤维兴奋有关．     

Winter forest soil respiration controlled by climate and microbial community composition

Most terrestrial carbon sequestration at mid-latitudes in the Northern Hemisphere occurs in seasonal, montane forest ecosystems. Winter respiratory carbon dioxide losses from these ecosystems are high, and over half of the carbon assimilated by photosynthesis in the summer can be lost the following winter. The amount of winter carbon dioxide loss is potentially susceptible to changes in the depth of the snowpack; a shallower snowpack has less insulation potential, causing colder soil temperatures and potentially lower soil respiration rates. Recent climate analyses have shown widespread declines in the winter snowpack of mountain ecosystems in the western USA and Europe that are coupled to positive temperature anomalies. Here we study the effect of changes in snow cover on soil carbon cycling within the context of natural climate variation. We use a six-year record of net ecosystem carbon dioxide exchange in a subalpine forest to show that years with a reduced winter snowpack are accompanied by significantly lower rates of soil respiration. Furthermore, we show that the cause of the high sensitivity of soil respiration rate to changes in snow depth is a unique soil microbial community that exhibits exponential growth and high rates of substrate utilization at the cold temperatures that exist beneath the snow. Our observations suggest that a warmer climate may change soil carbon sequestration rates in forest ecosystems owing to changes in the depth of the insulating snow cover.     

Universal scaling of respiratory metabolism, size and nitrogen in plants

The scaling of respiratory metabolism to body size in animals is considered to be a fundamental law of nature, and there is substantial evidence for an approximate (3/4)-power relation. Studies suggest that plant respiratory metabolism also scales as the (3/4)-power of mass, and that higher plant and animal scaling follow similar rules owing to the predominance of fractal-like transport networks and associated allometric scaling. Here, however, using data obtained from about 500 laboratory and field-grown plants from 43 species and four experiments, we show that whole-plant respiration rate scales approximately isometrically (scaling exponent approximately 1) with total plant mass in individual experiments and has no common relation across all data. Moreover, consistent with theories about biochemically based physiological scaling, isometric scaling of whole-plant respiration rate to total nitrogen content is observed within and across all data sets, with a single relation common to all data. This isometric scaling is unaffected by growth conditions including variation in light, nitrogen availability, temperature and atmospheric CO2 concentration, and is similar within or among species or functional groups. These findings suggest that plants and animals follow different metabolic scaling relations, driven by distinct mechanisms.