1,3-Dipropyl-8-cyclopentylxanthine attenuates the NMDA response to hypoxia in the rat hippocampus

Excitatory amino acids may cause neuronal damage and death in cerebral hypoxia and ischemia, through the activation of different subtypes of glutamate receptors, in particular of the (NMDA) receptor. In the present work, the effect of hypoxia on the component of the field excitatory postsynaptic potential (fepsp) mediated by the NMDA receptor was studied in the hippocampal CA1 area of the rat. A period of 15 min of hypoxia induced virtual abolition of the NMDA receptor-mediated fepsp and a 94.8 ± 0.7% maximal decrease in the fepsp. A period of 3 min of hypoxia induced a 89.3 ± 12.3% maximal decrease in the NMDA receptor-mediated component of the fepsp and only a 50.8 ± 11.5% maximal decrease in the fepsp. Both periods of hypoxia thus induced a more pronounced depression of the NMDA receptor-mediated component of the fepsp than of the fepsp. We found that 48.5 ± 9.1% decrease (about half of the total decrease) in the NMDA receptor-mediated fepsp, and 51.6 ± 19.6% decrease (approximately all decrease) in the fepsp induced by hypoxia (3 min) were reversed in the presence of the selective adenosine A₁ receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) (50 nM), and thus likely to be mediated by endogenous adenosine, through the activation of adenosine A₁ receptors. On the other hand, under the conditions we assumed to be normoxic in our slices, DPCPX (50 nM) induced a much larger increase in the amplitude of the NMDA receptor-mediated fepsp compared to the increase in the fepsp, which suggest that endogenous adenosine is inhibiting predominantly the NMDA receptor-mediated fepsp under these conditions. Hypoxia markedly decreases the NMDA receptor-mediated fepsp in the hippocampal CA₁ area. The contribution of endogenous adenosine to the inhibition of the NMDA receptor-mediated fepsp may be fundamental for its neuroprotective effects.     

Inhibitory effect of adenosine on electrically evoked contractions in the rat vas deferens: pharmacological characterization

The inhibitory effects of adenosine as well as its related analogues on the contractile response of the rat vas deferens to field stimulation were compared in the absence and in the presence of nitrobenzylthioguanosine (NBTGR), a potent adenosine uptake inhibitor. In the presence of NBTGR, the order of potency was N6-cyclohexyladenosine (CHA) greater than or equal to L-N6-phenylisopropyladenosine (L-PIA) greater than 2-chloroadenosine greater than D-N6-phenylisopropyladenosine (D-PIA) greater than or equal to adenosine greater than 2'-deoxyadenosine. The inhibitory effect of adenosine but not that of clonidine, beta-endorphin and somatostatin was blocked by 1,3-diethyl-8-phenylxanthine (DPX, pA2 = 7.2), a potent P1-purinergic antagonist. The results suggest that adenosine inhibited the electrically evoked contractions of the rat vas deferens via the activation of the A1 subtype of P1-purinergic receptors.     

Characterization of Hprt mutations in cDNA and genomic DNA of T-cell mutants from control and 1,3-butadiene-exposed male B6C3F1 mice and F344 rats

A multiplex PCR procedure for analysis of genomic DNA mutations in the mouse hypoxanthine-guanine phosphoribosyltransferase (Hprt) gene was developed and then used with other established methods for the coincident identification of large- and small-scale genetic alterations in the Hprt gene of mutant T-cell isolates propagated from sham- and 1,3-butadiene (BD)-exposed mice and rats. The spectra data for RT-PCR/cDNA analysis and multiplex PCR of genomic DNA from Hprt mutants were combined, and statistical analyses of the mutant fractions for the classes of mutations identified in control versus exposed animals were conducted. Under the assumption that the mutant fractions are distributed as Poisson variates, BD exposure of mice significantly increased the frequencies of (1) nearly all types of base substitutions; (2) single-base deletions and insertions; and (3) all subcategories of deletions. Significantly elevated fractions of G:C-->C:G and A:T-->T:A transversions in the Hprt gene of BD-exposed mice were consistent with the occurrence of these substitutions as the predominant ras gene mutations in multiple tumor types increased in incidence in carcinogenicity studies of BD in mice. BD exposure of rats produced significant increases in (1) base substitutions only at A:T base pairs; (2) single-base insertions; (3) complex mutations; and (4) deletions (mainly 5' partial and complete gene deletions). Future coincident analyses of large- and small-scale mutations in rodents exposed to specific BD metabolites should help identify species differences in the sources of deletion mutations and other types of mutations induced by BD exposures in mice versus rats.     

异种移植免疫学及其潜在风险的研究进展

同种器官移植成功率的提高导致了供体器官的严重短缺.采用解剖学上与人类相近的动物,比如猪的器官可以解决这种危机.但从猪到人的器官移植需要克服很多障碍,包括免疫学,生理学及其伦理道德问题.超急性排斥反应是猪到人异种器官移植的首要免疫学障碍,目前主要通过敲除半乳糖α1,3半乳糖(galactose-α1,3-galactose,Gal)抗原来克服超急性排斥反应.除此之外,仍有其它的非-Gal抗原可能引起猪到人的移植物的失功,例如N-羟乙酰神经氨酸等.除了免疫学障碍,猪器官携带的病毒及可能引起的异种移植的潜在风险也不容忽视.虽然现在还没有明显的实验数据显示猪到人的病原体的感染,但当猪到人的免疫学障碍被克服后,感染将成为又一研究热点.     

Separation and determination of the two components of glycerol formal by high-performance liquid chromatography

The two isomeric components of glycerol formal, 1,3-dioxan-5-ol and 1,3-dioxolane-4-methanol, are marginally separated (R_s = 1.0) by polar-bonded-phase high-performance liquid chromatography (HPLC) on a cyanopropyl column with acetone—hexane as the eluent. Esterification of these components with 3,5-dinitrobenzoyl chloride produces derivatives which are, however, completely resolved (R_s > 2) by normal-phase HPLC on silica; derivatization has the added advantage of introducing an ultraviolet-absorbing chromophore into each component. Preparative scale chromatography is used to isolate each of the derivatives, which are characterized by their UV, NMR and mass spectral properties. These esters are used as reference standards for an analytical method based on derivatization and normal-phase chromatography. In this way a sample of glycerol formal is calibrated for use as a standard in the direct determination of the two components by polar-bonded-phase HPLC.     

基于Heracles NEO超快速气相电子鼻麸炒白术炮制全过程气味变化识别研究

目的 建立麸炒白术Atractylodis Macrocephalae Rhizoma炮制全过程的定性判别模型,筛选出可以表征麸炒白术不同炮制程度的气味成分。方法 制备麸炒白术饮片,不同时间点取样进行分析。采用Heracles NEO超快速气相电子鼻采集气味图谱,与Arochembase数据库对比得到气味成分信息,结合峰面积分析气味成分的变化规律并进行化学计量学分析。结果 通过判别因子分析（discriminant factor analysis,DFA）、正交偏最小二乘-判别分析（orthogonal partial least squaresdiscriminant analysis,OPLS-DA）、层次聚类分析（hierarchical cluster analysis,HCA）等将麸炒白术炮制全过程样品成功分为4类：生品、炮制不及、炮制成品和炮制太过。在炮制过程中,3-甲基十五烷、十二烷基丙酸酯、正辛基环己烷、1,3-二硝基苯、8-甲基十五烷5个气味成分的峰面积占比较高,其中1,3-二硝基苯在炮制全过程中峰面积呈降低趋势;3-甲基十五烷从炮制不及到炮制成品的过程中峰面积呈增加...     

无热量超短波对脑缺血再灌注损伤大鼠早期CoQ10和C1GALT1C1表达的影响

目的： 探讨脑缺血再灌注损伤大鼠在不同时间点予以无热量超短波(ultrashort wave,USW)治疗后脑内 辅酶Q10(coenzyme Q10,CoQ10)、β1,3-半乳糖基转移酶-特异性伴侣1(β1,3-galactosyl transferase specific chaperone 1, C1GALT1C1)表达水平的变化趋势及其对缺血性脑损伤的保护机制。方法： 50 只Sprague-Dawley 大鼠随机分为5 组, 每组10 只。1 组是作为对照的假手术组,线栓插入深度为1 cm;其余4 组为实验组(分别为模型1 d 组、USW1 d 组、 模型3 d 组、USW3 d 组),线栓插入深度为18 mm,2 h 后予以再灌注。4 个实验组中,每组随机选取5 只大鼠行盐酸 2,3,5-三苯基四氮(2,3,5-triphenyltetrazoliumchloride,TTC)染色,其余5 只大鼠行蛋白质印迹法和real-time PCR检测, 观察比较各组大鼠脑梗死体积百分比值和缺血侧大脑中CoQ10 和C1GALT1C1 的相对表达量。结果： TTC染色后所 得脑梗死体积百分比值中,假手术组未见脑梗死,比值为0;实验组随着病程延长和USW治疗呈下降趋势,差异均 有统计学意义(均P<0.05)。蛋白质印迹法和real-time PCR 检测显示：假手术组CoQ10 相对表达量最高,但实验组 CoQ10 相对表达量随着病程延长和USW治疗呈上升趋势,差异均有统计学意义(均P<0.05);假手术组C1GALT1C1 的相对表达量最低,但实验组C1GALT1C1 的相对表达量随着病程延长和USW治疗呈下降趋势,差异均有统计学意 义(均P<0.05)。结论： 无热量USW治疗脑缺血再灌注损伤大鼠,可能通过上调CoQ10 表达及下调C1GALT1C1 表达 而发挥保护作用。     

Regional differences of the effect of σ receptor ligands on the acetylcholine release in the rat brain

Summary We found that a receptor ligands differentially regulated the acetylcholine (ACh) neurotransmission in the rat brain. Acute administration of (+)-N-allylnormetazocine [(+)-SKF-10,047], a prototype ₁ receptor ligand, and 1,3-di(2-tolyl)guanidine (DTG), a non-specific receptor ligand, increased the extracellular ACh level in the rat hippocampus. This increase of hippocampal extracellular ACh level elicited by (+)-SKF-10,047 was more potent than that elicited by DTG. On the other hand, the striatal extracellular ACh level was slightly affected by (+)-SKF-10,047. In addition, DTG did not affect the striatal extracellular ACh level. Our previous studies have shown that both (+)-SKF-10,047 and DTG increased the extracellular ACh level in the rat frontal cortex. Taking all these data into consideration, the regulation of ACh neurotransmission by receptor ligands are different depending upon the brain region.     

Carcinogenic activity of cigarette smoke gas phase and its modulation by beta-carotene and N-acetylcysteine.

Male strain A/J mice were exposed for six hours a day, five days a week for six months to either full tobacco smoke or to tobacco smoke drawn through a HEPA filter that removed more than 99% of particulate matter. After another four months in air, the animals were sacrificed and lung tumors were counted for calculation of multiplicities and incidences. Analysis of the chamber atmospheres showed that in the filtered smoke the concentrations of polycyclic aromatic hydrocarbons and tobacco smoke specific nitrosamines were reduced to from below 18% to even nondetectable levels of the original values measured in the unfiltered smoke. Aldehydes and other volatile organic compounds such as 1,3-butadiene, benzene, or acrolein were reduced to about 50 to 90% of the concentrations found in unfiltered smoke. Some potentially carcinogenic metals reached levels in filtered smoke ranging from 77% to less than 1% found in full smoke. The mice exposed to the filtered smoke atmosphere had practically identical lung tumor multiplicities and incidence as had the animals exposed to full smoke, significantly higher than in air exposed controls. Diets containing 0.5% beta-carotene or 0.4% N-acetylcysteine afforded some chemoprevention. It was tentatively concluded that 1,3-butadiene might be an important contributor to lung tumorigenesis in this mouse model of tobacco smoke carcinogenesis.     

HPLC同时测定慢性阻塞性肺病患者血浆中的茶碱和1,3-二甲基尿酸

目的 采用HPLC法同时测定慢性阻塞性肺病(COPD)患者血浆中的茶碱及其代谢物1,3-二甲基尿酸(1,3-DMU).方法 色谱柱为Hypersil BDS C18柱(250 mm×4.6 mm,5μm),流动相为乙腈-水(7∶93),流速1 mL·min-1,检测波长280 nm.43名COPD患者连续服用茶碱(100 mg,bid)两周后,测定茶碱及1,3-DMU的血药浓度.结果 茶碱、1,3-DMU的线性范围分别为0.20 ～ 10.00 μg∶ mL-1(r=0.9998)、0.05 ～ 2.00 μg∶ mL-(r=0.9996);日内、日间RSD均≤12.91％,提取回收率分别为77.52％ ～79.22％、71.69％ ～ 74.02％;患者的平均茶碱血药浓度为3.57±1.59 μg∶ mL-1,茶碱和1,3-DMU的浓度呈强相关(r=0.672),1,3-DMU/茶碱为0.064±0.024.结论 所用方法简便、快速、准确,可用于COPD患者茶碱血药浓度的监测,1,3-DMU与茶碱浓度的比值可评估不同个体对茶碱清除率的差异.