微波辐射对小鼠脑内乙酰胆碱含量及胆碱乙酸转移酶活性的影响

用频率为2450MHz功率密度为10mW/Cm~2(WBASAR约11.4W/kg)的微波(连续波)对置于微波暗室内的昆明种雄性小鼠急性全身照射1小时后,立即按常规方法断头,取脑,制成样品,然后用放射免疫测定法测量小鼠脑内乙酰胆碱(ACh)含量及胆碱乙酰转移酶(ChAT)活性。结果表明:照射组的ACh含量为11.6±1.4pmol/mg(脑鲜重),ChAT活性为45.4±8.7pmolACh/min.mg(脑鲜重);而对照组的分别为16.0±2.1pmol/mg和61.0±13.8pmolACh/min.mg。证明微波照射后可引起动物脑内ACh水平和ChAT活性下降,提示微波辐射对中枢胆碱能系统确有不利影响。     

丙线照射后小鼠小肠ACh含量ChE活性变化及其原因的初步探讨

本文观察了电离辐射后小鼠小肠组织中ACh含量,ChE活性变化,并对其机制进行探讨,结果如下; 1.丙线照射后小鼠小肠ACh含量增加,ChE活性降低。其变化程度与照射剂量和照后时间有关。一定剂量范围内,照射剂量愈大,ChE活性愈低,ACh含量愈高。 2.照射后小肠粘膜脱落是ChE活性降低的主要原因,ACh含量增加除因ChE活性降低外,ChAT活性增高也许是ACh含量增高的主要原因。     

慢性缺氧对大鼠肺动脉内皮依赖性舒张反应及cGMP含量的影响

本实验观察了慢性缺氧对大鼠肺动脉内皮依赖性舒张反应和肺动脉内环磷酸鸟苷(cGMP)含量的影响。乙酰胆碱(ACh)和三磷酸腺苷(ATP)可使正常大鼠的离体肺动脉产生内皮依赖性舒张反应,其舒张作用不受消炎痛的影响,但被甲烯蓝完全抑制。慢性缺氧明显减低了 ACh 和 ATP 诱发的大鼠肺内和肺外动脉的内皮依赖性舒张反应。当 ACh 浓度为10~(-6)mol/L 时,缺氧组大鼠肺内和肺外动脉舒张百分数分别为对照组的61.3%和59.2%;当 ATP浓度为1.8×10~(-5)mol/L 时,缺氧组大鼠肺内和肺外动脉舒张反应分別为对照组的64.9%和55.3%。慢性缺氧也减低了硝普钠(SNP)诱发的大鼠肺动脉非内皮依赖性舒张反应。慢性缺氧显著减低了大鼠肺动脉内 cGMP 的含量。缺氧组和对照组大鼠肺动脉内 cGMP 的基础含量分别是51.9±5.7 pmol/g wet wt.(n=14)和84.9±9.7 pmol/g wet wt.(n=14),p<0.01;经 10~(-7)mol/L ACh 刺激后分别是91.4±7.3 pmol/g wet wt.(n=5)和240.8±30.6pmol/g wet wt.(n=5),p<0.01。慢性缺氧可能抑制了肺动脉平滑肌细胞胞浆中可溶性鸟苷酸环化酶,从而减低了肺动脉对内皮舒张因子和 SNP 的舒张反应性。     

大鼠脑室内注射ANGⅡ和ANGⅡ抗体对尿钠排出和肾皮质Na~+·K~+-ATPase的影响

在麻醉大鼠的侧脑室注射16pg血管紧张素Ⅱ(ANGⅡ),15min内出现尿钠增多的反应并持续90min,平均动脉血压保持稳定。肾皮质Na~+·K~+-ATPase活性(1.51±0.26μmolPi/mg Pro·h)显著低于侧脑室注射人工脑脊液的对照值(2.66±0.28μmol Pi/mg Pro·h,P<0.01),而侧脑室注射ANGⅡ抗体后5min内则出现尿钠减少的反应并持续135min。肾皮质Na~+·K~+-ATPase活性(3.61±0.34μmol Pi/mg Pro·h)显著高于对照值(P<0.05)。股静脉和脊髓蛛网膜下腔分别注射16pg ANGⅡ,均未出现尿钠增多的反应。结果表明,脑内的内源性ANGⅡ具有引起尿钠增多的作用;并提示这种作用可能与肾脏Na~+·K~+-ATPase活性的抑制有关。     

中国人肝脏细胞色素P450 2E1表达——基因型与表型的关系

细胞色素P450(CYP)2E1代谢激活多种致癌物并参与酒精代谢和自由基形成,其基因启动子区RsaⅠ单核苷酸多态与酒精性肝病和某些癌症如食管癌和肺癌的易感性相关.以免疫印迹和特异底物的方法研究了RsaⅠ识别的不同基因型肝脏标本中CYP2E1蛋白含量及其功能活性的差异.结果表明,c1/c1基因型(n=28)的蛋白含量((124.0±83.9)pmol/mg)高于携带至少一个c2等位基因的变异基因型((65.5 ± 38.9)pmol/mg,n=22),差异有极显著性(P<0.01).c1/c1基因型的肝微粒体代谢4-硝基苯酚的活性也同样显著高于变异基因型((198.4 ± 27.8)pmol/(min· mg)比 (101.2 ± 18.1)pmol/(min·mg),P <0.01)).结果证明,CYP2E1表达水平和酶活性的个体差异与RsaⅠ识别的基因多态有关,这与分子流行病学研究发现的c1/c1基因型是某些癌症的遗传易感因素一致.     

神经元营养因子对大鼠隔—海马通路损伤的影响

为评价神经生长因子(NGF)、混合型神经节苷脂(GM)和单唾液酸神经节苷脂(GM1)对中枢胆碱能神经损伤早期的影响,在大鼠单侧隔-海马通路部分损伤后即时经脑室分别注入上述三种神经元营养因子,7d后取两侧海马分别测定乙酰胆碱(ACh)、胆碱乙酰基转移酶(ChAT)和胆碱酯酶(ChE)。损伤对照组(脑室注入盐水)术侧海马ACh含量保留率为对侧的20.3％,ChAT活力为50％,ChE活力为48.3％。给予NGF、GM或GM1的实验组,ACh含量保留率分别为34.9％,35.3％和47.7％;ChAT活力为77.4％,78.4％和69.2％;而ChE活力的保留率未见明显改变。这些神经元营养因子显著增加了大鼠隔-海马通路损伤后海马内ACh含量和ChAT活力,说明它们减轻了损伤侧海马胆碱能神经纤维的破坏,具有明显的损伤早期保护作用。     

p18INK4C基因缺失增强造血干细胞在亚致死剂量

观察p18^INK4C (p18)基因缺失对造血干细胞(HSC)在亚致死剂量照射小鼠体内长期植入的影响. 供体为p18基因缺失型(p18^-/-)纯系C57BL/6小鼠(CD45.2表型), 竞争性细胞来源于C57BL/6-Ly5.1(CD45.1/2)双表型小鼠, 受体为野生型(p18^+/+)C57BL/6-Ly5.1(CD45.1)小鼠. 竞争性骨髓移植(cBMT)实验根据受体小鼠照射剂量的不同分为3个剂量组(10 Gy, 5 Gy和1 Gy). 供体细胞和竞争性细胞1:1混合后移植, 移植后采集外周血和骨髓细胞用流式细胞仪检测各细胞比例. 造血恢复移植实验: 移植后检测外周血白细胞计数评价移植后造血恢复速度. 10和5 Gy照射剂量组, 供体细胞和竞争性细胞成功植入, 而1 Gy照射剂量组无供体细胞植入. 无论在10 Gy或是5 Gy照射剂量情况下, 供体细胞在受体内的比例均高于竞争性细胞. 移植后6周, 10和5 Gy照射剂量时外周血中供体细胞比例分别为竞争性细胞的1.46±0.21倍和1.64±0.43倍, 14周时分别为竞争性细胞的1.84±0.25倍和2.00±0.49倍, 26周时分别为竞争性细胞的3.13±0.79倍和3.24±1.33倍. 移植后6个月, 10 Gy照射剂量时骨髓细胞中供体细胞比例为竞争性细胞的7.68±4.42倍, 5 Gy照射剂量时为竞争性细胞的10.83±2.98倍. 移植后6个月, 在10和5 Gy照射剂量组之间骨髓中造血细胞植入率相当, 分别为(85.53±8.71)%和(80.87±2.87)% (P = 0.457). p18^-/-细胞与p18^+/+细胞相比, 移植后造血恢复的速度相当. p18基因缺失可以显著增强HSC在亚致死剂量照射小鼠体内的长期植入能力.     

人红细胞内乙酰胆碱/胆碱活度的微电极测量及临床意义

本文采用新发展的乙酰胆碱/胆碱(ACh/Ch)离子选择微电极对人体单个红细胞内的ACh/Ch活度进行了测量。实验对象是25位正常人及8位躁狂症病人的红细胞。正常人红细胞内ACh/Ch的活度值为24.O±8.3×10^-6mol/L,而躁狂症病人的红细胞内ACh/Ch的活度值为98.3±41.4×10^-6mol/L,是正常人的4倍。本文对ACh/Ch离子选择微电极的结构和特性参数亦作了描述。     

急性低血压对前庭神经内侧核区谷氨酸和牛磺酸含量的影响

本实验用脑部微量透析法和高效液相色谱法观察急性失血诱发大鼠低血压时前庭神经内侧核(medial vestibular nucleus,MVN)内氨基酸类神经递质谷氨酸(glutamate,Glu)和牛磺酸(tautine,Tau)含量的变化,以了解MVN内这些氨基酸类递质是否参与血压的调节。实验观察到,正常血压大鼠MVN内Glu和Tau浓度在透析探针植入90 min后趋于稳定,此时 Glu的平均含量为(18．96±0．27)pmol／8 μl透析液,Tau的平均含量为(7．73±0．05)pmol/8μl透析液。动脉抽血1．5 ml诱发急性低血压时,同侧MVN区Glu含量增加(P<0．05),Tau含量减少(P<0．05)。用利多卡因(lidocaine)短时阻断前庭传入及用化学方法永久破坏单侧前庭器官后,动脉抽血1.5 ml使血压降低30％,同侧MVN内氨基酸类神经递质无明显改变。结果提示,急性失血引起的低血压可通过前庭器官影响MVN的活动,该区内氨基酸类递质可能参与这一活动的调节。     

DNA oxidation and superoxide dismutase in the kidney of diabetic animals: effects of pioglitazone and repaglinide

In the present study, DNA oxidative damage was elevated and superoxide dismutase (Cu,Zn-SOD) metabolism was disturbed in the kidney of alloxan-induced diabetic animals. The effects of pioglitazone and repaglinide, new oral antidiabetics, on 8-hydroxy-2′-deoxyguanosine (8-OHdG) and Cu,Zn-SOD were studied. Diabetic versus control levels (mean ± SE) of 8-OHdG were 24.9 ± 0.2 vs. 21.8 ± 0.1 and 21.5 ± 0.2 vs 20.1 ± 0.2 pmol/μg DNA after 4 and 8 weeks, respectively. At p<0.05, pioglitazone diminished this parameter in diabetic animals (22.0 ± 0.2 and 20.1 ± 0.3 pmol/μg DNA). The level was not affected in diabetic groups receiving repaglinide (24.9 ± 0.2 and 21.5 ± 0.3 pmol/μg DNA). In diabetic kidney, Cu,Zn-SOD mRNA was diminished relative to control animals and was modulated by pioglitazone and repaglinide treatments. Simultaneously, Cu,Zn-SOD activity was also diminished (1.5 ± 0.2 vs. 2.8 ± 0.3 and 1.8 ± 0.1 vs 2.9 ± 0.3 U/mg protein after 4 and 8 weeks, respectively) and partly changed after pioglitazone (2.1 ± 0.4 and 2.3 ± 0.3 U/mg protein) and repaglinide (2.0 ± 0.1 and 2.4 ± 0.2 U/mg protein). These results suggest that a reduction in oxidative stress in diabetic kidney can be achieved with the administration of pioglitazone and to some extent using repaglinide treatment.     

Tuning of electronic properties of one-dimensional cyano-bridged Cu-Ni, Cu-Pd, and Cu-Pt bimetallic assemblies by stereochemistry of ligands

Preparations, XPS and electronic spectroscopy, and magnetism of seven new one-dimensional cyano-bridged coordination polymers, chiral [Cu(RR-chxn)₂][Pd(CN)₄] · 2H₂O (1), [Cu(trans-chxn)₂][M(CN)₄] · 2H₂O (2, 4, and 6 for M = Pd, Ni, and Pt), and [Cu(cis-chxn)₂][M(CN)₄] · 2H₂O (3, 5, and 7 for M = Pd, Ni, and Pt) (RR-chxn = cyclohexane-(1R,2R)-diamine, trans-chxn = racemic trans-cyclohexane-(1,2)-diamine, and cis-chxn = racemic cis-cyclohexane-(1,2)-diamine) have been reported in view of tuning of their electronic properties by stereochemistry of chxn ligands and metal-substitution. Comparison of Cu 2p_1/2 and 2p_3/2 peaks of XPS and broad d-d bands around 18 000 cm⁻¹ of electronic spectra are described systematically for 1-7. Variable-temperature magnetic measurement shows that complexes 1-7 indicate weak antiferromagnetic interactions via cyano-bridges. Because of semi-coordination coupled with pseudo Jahn-Teller elongation and electrostatic interaction for 1, the axial Cu-N coordination bond distances of 2.330(7) and 3.092(8) Å are considerably longer than those of equatorial ones in the range from 2.016(6) to 2.030(6) Å. The former bond distances of 1 are intermediate values among the related Ni (2.324(6) and 3.120(8) Å) and Pt (2.34(1) and 3.09(1) Å) complexes.     

Land,livestock, and livelihoods: Changing dynamics of gender,caste, and ethnicity in a Nepalese Village

Over the past 10 years, Ghusel VDC, Lalitpur District has moved from primarily subsistence agriculture into the wider cash economy aided by the Small Farmers' Development Program (SFDP), which provides credit to farmers mainly for the purchase of buffalo for milk production, and by the National Dairy Corporation, which supports local dairy cooperatives. Analysis reveals that buffalo-keeping and milk sales are increasing the well-being of many households, while at the same time creating new inequalities in gender roles and responsibilities, greater inequities between Brahmin and Tamang residents in Ghusel, and placing pressures on the ecosystem for increased supplies of fodder and fuelwood. Evidence suggests that there is critical, need for attention to the social, and particularly gender-based, implications of maintaining livestock for milk sales and to the ecological underpinnings of this livelihood system.     

Structure and function of S-adenosylhomocysteine hydrolase

In mammals, S-adenosylhomocysteine hydrolase (AdoHcyase) is the only known enzyme to catalyze the breakdown of S-adenosylhomocysteine (AdoHcy) to homocysteine and adenosine. AdoHcy is the product of all adenosylmethionine (AdoMet)-dependent biological transmethylations. These reactions have a wide range of products, and are common in all facets of biometabolism. As a product inhibitor, elevated levels of AdoHcy suppress AdoMet-dependent transmethylations. Thus, AdoHcyase is a regulator of biological transmethylation in general. The three-dimensional structure of AdoHcyase complexed with reduced nicotinamide adenine dinucleotide phosphate (NADH) and the inhibitor (1′R, 2′S, 3′R)-9-(2′,3′-dihyroxycyclopenten-1-yl)adenine (DHCeA) was solved by a combination of the crystallographic direct methods program, SnB, to determine the selenium atom substructure and by treating the multiwavelength anomalous diffraction data as a special case of multiple isomorphous replacement. The enzyme architecture resembles that observed for NAD-dependent dehydrogenases, with the catalytic domain and the cofactor binding domain each containing a modified Rossmann fold. The two domains form a deep active site cleft containing the cofactor and bound inhibitor molecule. A comparison of the inhibitor complex of the human enzyme and the structure of the rat enzyme, solved without inhibitor, suggests that a 17° rigid body movement of the catalytic domain occurs upon inhibitor/substrate binding.     

Chiral Separation of G‐type Chemical Warfare Nerve Agents via Analytical Supercritical Fluid Chromatography

Chemical warfare nerve agents (CWNAs) are extremely toxic organophosphorus compounds that contain a chiral phosphorus center. Undirected synthesis of G‐type CWNAs produces stereoisomers of tabun, sarin, soman, and cyclosarin (GA, GB, GD, and GF, respectively). Analytical‐scale methods were developed using a supercritical fluid chromatography (SFC) system in tandem with a mass spectrometer for the separation, quantitation, and isolation of individual stereoisomers of GA, GB, GD, and GF. Screening various chiral stationary phases (CSPs) for the capacity to provide full baseline separation of the CWNAs revealed that a Regis WhelkO1 (SS) column was capable of separating the enantiomers of GA, GB, and GF, with elution of the P(+) enantiomer preceding elution of the corresponding P(–) enantiomer; two WhelkO1 (SS) columns had to be connected in series to achieve complete baseline resolution. The four diastereomers of GD were also resolved using two tandem WhelkO1 (SS) columns, with complete baseline separation of the two P(+) epimers. A single WhelkO1 (RR) column with inverse stereochemistry resulted in baseline separation of the GD P(–) epimers. The analytical methods described can be scaled to allow isolation of individual stereoisomers to assist in screening and development of countermeasures to organophosphorus nerve agents. Chirality 26:817–824, 2014. © 2014 The Authors. Chirality published by John Wiley Periodicals, Inc.     

Influence of Fluoride on Rat Kidney Antioxidant System: Effects of Methionine and Vitamin E

The aim of the study has been to determine and compare the influence upon the kidney antioxidative system, exercised by administration of vitamin E, and vitamin E in combination with methionine, under conditions of oxidative stress induced by sodium fluoride. The experiment was carried out on Wistar FL rats (adult males) that, for 35 days, were administered water, NaF, NaF with vitamin E, or vitamin E with methionine (doses: 10 mg NaF/kg of body mass/24 h, 3 mg vitamin E per 10 μl per rat for 24 h, 2 mg methionine per rat for 24 h). The influence of administered sodium fluoride and antioxidants upon the antioxidative system in kidney was examined by analyzing the concentration of malondialdehyde (MDA) and the activity of the most important antioxidative enzymes (SOD, total and both its isoenzymes, GPX, GST, GR, and CAT). The studies carried out confirmed the disadvantageous effect of the administered dose of NaF upon the antixodiative system in rats (increase in the concentration MDA, decrease activity of all antioxidative enzymes). The administration of vitamin E increased the activity of studied enzymes with the exception of glutathione reductase GR; it also reduced the procesess of lipid peroxidation. It has been found that combined doses of vitamin E and methionine were most effective in inhibiting lipid peroxidation processes. The results confirmed the antioxidative properties of methionine.     

Reorientation of Microfibrils and Microtubules at the Outer Epidermal Wall of Maize Coleoptiles During Auxin-Mediated Growth

Auxin-mediated elongation growth of isolated subapical coleoptile segments of maize (Zea mays L.) is controlled by the extensibility of the outer cell wall of the outer epidermis (Kutschera et al., 1987). Here we investigate the hypothesis that auxin controls the extensibility of this wall by changing the orientation of newly deposited microfibrils through a corresponding change in the orientation of cortical microtubules. On the basis of electron micrographs it is shown that cessation of growth after removal of the endogenous source of auxin is correlated with a relative increase of longitudinally orientated microfibrils and microtubules at the inner wall surface. Conversely, reinduction of growth by exogenous auxin is correlated with a relative increase of transversely orientated microfibrils and microtubules at the inner wall surface. These changes can be detected 30–60 min after the removal and addition of auxin, respectively. The functional significance of directional changes of newly desposited wall microfibrils for the control of elongation growth is discussed.     

Gamma-glutamylcysteine protects ergothioneine-deficient Mycobacterium tuberculosis mutants against oxidative and nitrosative stress

Mycobacterium tuberculosis (M.tb.), the causative agent of tuberculosis (TB), cannot synthesize GSH, but synthesizes two major low molecular weight thiols namely mycothiol (MSH) and ergothioneine (ERG). Gamma-glutamylcysteine (GGC), an intermediate in GSH synthesis, has been implicated in the protection of lactic acid bacteria from oxidative stress in the absence of GSH. In mycobacteria, GGC is an intermediate in ERG biosynthesis, and its formation is catalysed by EgtA (GshA). GGC is subsequently used by EgtB in the formation of hercynine-sulphoxide-GGC. In this study, M.tb. mutants harbouring unmarked, in-frame deletions in each of the fives genes involved in ERG biosynthesis (egtA, egtB, egtC, egtD and egtE) or a marked deletion of the mshA gene (required for MSH biosynthesis) were generated. Liquid chromatography tandem mass spectrometry analyses (LC-MS) revealed that the production of GGC was elevated in the MSH-deficient and the ERG-deficient mutants. The ERG-deficient ΔegtB mutant which accumulated GGC was more resistant to oxidative and nitrosative stress than the ERG-deficient, GGC-deficient ΔegtA mutant. This implicates GGC in the detoxification of reactive oxygen and nitrogen species in M.tb.     

In vitro studies of the rabbit immune system. IV. Differential mitogen responses of isolated T and B cells.

The mitogenic responses of separated rabbit lymphocyte populations functionally analogous to mouse T and B cells have been tested in vitro. Purified T cells were prepared by passage over nylon wool (NW) and purified B cells prepared by treatment with antithymocyte serum and complement (ATS + C). ATS + C kills 70% of peripheral blood lymphocytes (PBL's) and 50% of the spleen cells while passage over NW yields 40% of the applied PBL's and 5–23% of the applied spleen cells. NW-purified T cells from the spleen or PBL's respond fully to concanavalin A (Con A) but have a reduced response to phytohemaglutinin (PHA) and little or no response to goat anti-rabbit immunoglobulin (anti-Ig). PBL's that survive ATS + C (B cells) are stimulated by anti-Ig but not by Con A or PHA. B cells purified from spleen do not respond to Con A or PHA but will respond to anti-Ig under appropriate conditions. A full spleen B-cell response to anti-Ig required removal of Ig produced by the cultures that blocked anti-Ig stimulation. It is concluded that, for rabbit lymphocytes, Con A and PHA are primarily T-cell mitogens and that anti-Ig is primarily a B-cell mitogen. However, the mitogen response of unfractionated PBL or spleen cell populations indicates an overlap in reactivity. This could be due to cells sharing T and B properties, alteration of cell populations by the fractionation procedures used, or recruitment of one population in the presence of a mitogenic response of the other population.     

八种脑-肠肽侧脑室内注射对大鼠基础胃酸分泌的影响

用乌拉坦麻醉大鼠作急性实验,采用连续灌流胃并收集流出液的方法,观察向侧脑室内注射微量脑-肠肽对大鼠基础胃酸分泌的影响。实验结果如下:(1)雨蛙肽、八肽胆囊收缩素、促甲状腺素释放激素及四肽胃泌素均使总酸排出量增加;(2)生长抑素、胰多肽、P 物质、胰高血糖素则使总酸排出量减少;(3)上述肽类用侧脑室注射的剂量作肌肉注射,除四肽胃泌素也产生明显的刺激胃酸分泌作用外,对胃酸分泌均无明显影响。以上结果提示,脑内的一些肽类可能以神经递质或调制物的方式,参与中枢对胃酸分泌的调节。     

A chromium-tolerant plant growing in Cr-contaminated land

In this paper, a kind of Typhaceae plant species, Typha angustifolia L, with a high tolerance to Cr is described. Experiments were carried out to examine its ability to tolerant Cr and its physiological response. The results showed that there was no difference in growth, plant height, and biomass response to external Cr (VI) between the plants exposed to 100 microM Cr (VI) and control (0 microM), while increasing Cr levels to 200-800 microM induced a significant decrease in plant height and biomass, but no significant injury was detected, even for the plants exposed to 800 microM Cr. Chromium induced significant increases in superoxide dismutase (SOD) and peroxidase (POD) activities. Meanwhile, a significantly positive correlation was found between Cr and Mn or Cu in leaves and roots, respectively. The Cr tolerance of the plant appeared to be associated with the enhancement of SOD and POD activities and the improvement in uptake and translocation of the essential microelements.