Cytometric analysis of the DNA content of the thymus, spleen and liver in C57BL/6 mice

Flow cytometric analysis of cell DNA content in the mouse C 57 BL/6 shows better results with fine needle aspiration than with mechanical dissociation of the tissues. There is no difference fresh and deep frozen stored tissues. In the liver, it has been found two cell populations with different DNA content including diploid and tetraploid cell lines. In the spleen and the thymus, only diploid cells are encountered with different cell cycles belonging to the organ.     

Oryzalin,a dinitroaniline herbicide,binds to plant tubulin and inhibits microtubule polymerization in vitro

The effects of oryzalin, a dinitroaniline herbicide, on chromosome behavior and on cellular microtubules (MTs) were examined by light microscopy and immunogold staining, respectively, in endosperm cells from Haemanthus katherinae Bak. Brief treatments with 1.0·10^-8 M oryzalin reduced markedly the migration rate of anaphase chromosomes and 1.0·10^-7 M oryzalin stopped migration abruptly. Oryzalin (1.0·10^-7 M) depolymerized MTs and prevented the polymerization of new MTs at all stages of the mitotic cycle. The chromosome condensation cycle was unaffected by oryzalin. Endothelial cells from the heart of Xenopus leavis showed no chromosomal or microtubular rearrangements after oryzalin treatment. The inhibition by oryzalin of the polymerization of tubulin isolated from cultured cells of Rosa sp. cv. Paul's scarlet was examined in vitro by turbidimetry, electron microscopy and polymer sedimentation analysis. Oryzalin inhibited the rapid phase of taxol-induced polymerization of rose MTs at 24°C with an apparent inhibition constant (K _i ) of 2.59·10⁶ M. Shorter and fewer MTs were formed with increasing oryzalin concentrations, and maximum inhibition of taxol-induced polymerization occurred at approx. 1:1 molar ratios of oryzalin and tubulin. Oryzalin partially depolymerized taxol-stabilized rose MTs. Ligand-binding experiments with [¹⁴C]oryzalin demonstrated the formation of a tubulin-oryzalin complex that was time- and pH-dependent. The tubulin-oryzalin interaction (24°C, pH 7.1) had an apparent affinity constant (K _app) of 1.19·10⁵ M^-1. Oryzalin did not inhibit taxol-induced polymerization of bovinebrain MTs and no appreciable binding of oryzalin to brain tubulin or other proteins was detected. The results demonstrate pharmacological differences between plant and animal tubulins and indicate that the most sensitive mode of action of the dinitroaniline herbicides is the direct poisoning of MT dynamics in cells of higher plants.Abbreviations MT microtubule - SIB sucrose isolation buffer - TO tubulin-oryzalin complex     

Dynamics of breathing in the hypoxic awake lamb

Newborn mammals respond to hypoxia with an immediate hyperventilation that is rapidly dampened. Changes in mechanical properties of the respiratory system during hypoxia have been considered an important reason for this fall in minute ventilation (VE). We have studied the dynamic mechanical behavior of the respiratory system in eight unanesthetized intact newborn lambs (mean age 2 days) during normoxia and hypoxia (FIO2 = 0.08). Mouth pressure (P), airflow (V), and volume (V) were recorded while lambs were breathing through a leak-proof face mask and a pneumotachograph. Active compliance (C') and resistance (R') of the respiratory system were computed from P developed during an inspiratory effort against airway closure at end expiration and V and V of the preceding breaths. Tidal expiratory V-V curves were analyzed to estimate the elevation in functional residual capacity (FRC) over resting volume (Vr). After hypoxia, there was an immediate increase in VE in the first 2 min, from 0.49 to 1.13 l.kg-1.min-1, followed by a rapid decrease to 0.80. After 8 min of hypoxia, C' was unchanged. The inspiratory R' decreased during hypoxia, probably reflecting a drop in inspiratory laryngeal resistance. The expiratory V-V curves during hypoxia showed considerable braking, often with a double peak in expiratory V. This pattern was only occasionally seen during normoxia. In animals with a linear segment of the expiratory V-V curves the FRC-Vr difference could be calculated and averaged 1.93 ml/kg during normoxia and 3.47 during hypoxia. The recoil P of the respiratory system at end expiration was 0.75 cmH2O during normoxia vs. 1.63 cmH2O during hypoxia (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Direct measurement of static chest wall compliance in animal and human neonates

The measurement of pulmonary mechanics has been developed extensively for adults, and these techniques have been applied directly to neonates and infants. However, the compliant chest wall of the infant frequently predisposes to chest wall distortion, especially when there is a low dynamic lung compliance (CL,dyn). We describe a technique of directly measuring the static chest wall compliance (Cw,st), developed initially in the newborn lamb and subsequently applied to the premature neonate with chest wall distortion. The mean CL,dyn in seven intubated newborn lambs in normoxia was 2.45 +/- 0.41 ml.cmH2O-1.kg-1, whereas Cw,st was 11.81 +/- 0.25 ml.cmH2O-1.kg-1. These values did not change significantly in seven animals breathing through a tight-fitting face mask or with hypercapnia-induced tachypnea. For the eight premature infants the mean CL,dyn was 1.35 +/- 0.36 ml.cmH2O-1.kg-1, whereas the mean Cw,st was 3.16 +/- 1.01 ml.cmH2O-1.kg-1. This study shows that, under relaxed conditions when measurements of static compliance are performed, the chest wall is more compliant than the lung. The measurement of Cw,st may thus be used to determine the contribution of the respiratory musculature in stabilizing the chest wall.     

纸坊病病毒病因的研究

1985年4～10月与1986年6～8月,在贵州省沿河县的纸坊村和崔家坨村先后发生了病因不明的传染病。纸坊村约有1/5的村民发病,病死率为12％,崔家坨村有1/10的村民发病,病死率高达30％。发病波及各年龄组,以青壮年为多,有家庭集聚现象。 本病起病急,轻症者只有头晕、乏力、肌痛、多汗、心悸伴以低热,有的初期有短暂的腹泻。重症者有高热(40℃以上)、大汗、心悸、游走性肌肉痉挛伴有明显疼痛和触痛,以腰骶部及四肢肌肉为好发部位。病人烦燥不安,2～5天内死亡。经实验室检查,排除了食物中毒、农药中毒、钩端螺旋体病和弓形体感染。从病人和接触者的粪便中分离到9株病毒,性状一致,为RNA型25nm的球形颗粒,耐酸,耐乙醚,能凝集人“O”型血球。经血清学鉴定为ECHO3型病毒。16份病人双份血清的检测结果表明,恢复期血清对该病毒中和抗体有4倍以上升高者共8例(纸坊村和崔家坨各4例)。病人单份血清也都有较高的抗体。有理由认为两年中先后在两个村庄发生的传染病与ECHO3型病毒有密切关系。查阅文献,尚未见有关ECHO3型病毒引起以肌痛、游走性肌痉挛为特征的疾病的报道。     

中水技术污水处理工艺去除病毒的效果

中水技术开发既可缓解水资源的紧缺,又能改善城市环境。本文报道用石英粉吸附/洗脱和浓缩棒脱水的二步浓集水病毒技术(回收率为25.4～37.3％),研究中水技术不同处理工艺去除病毒的效果。结果,二级处理可去除掺入病毒的98.9％,结合三级处理的混凝沉淀和过滤,可去除99.976％,再加活性炭吸附或加氯消毒,所得中水分别去除掺入病毒的99.986％和99.991％。经首都机场中水道试验厂水样检测表明,中水中未检测到病毒(<0.23PFU/L)。     

松辽盆地阿尔必期微体浮游植物新属种

该文描述了松辽盆地中白垩世阿尔必期泉头组三段的微体浮游植物化石1新属7新种,隶属于微咸水沟鞭藻类2属5新种(含4新亚种),淡水绿藻1属1种和疑源类1新属1新种。并对沟鞭藻 Ngktericysta Bint,1986进行了修订。     

松辽盆地白垩纪微体浮游植物群及其环境讨论

该文报道了松辽盆地白垩纪丰富的非海相微体浮游植物群,主要是沟鞭藻类及一些绿藻和疑源类;论述了藻类的生物地层特征,自下而上初步划分出10个组合带;结合微量元素和古地磁等资料,较详细地讨论了含微体浮游植物组段的沉积环境,认为松辽盆地在白垩纪至少遭受过两次重要的海侵(分别在青山口组一段及嫩江组一、二段沉积时期),导致古松辽湖泊五种不同水体环境的演替,指出微体浮游植物组合的变化是受古盐度、古温度和古水深等因素控制的。此外,对有关组段的地质时代也进行了讨论,进一步补充了新的浮游植物化石证据。