Dog cerebral cortex contains μ-, δ- and κ-opioid receptors at different densities: apparent lack of evidence for subtypes of the κ-receptor using selective radioligands

The biochemical and pharmacological properties of mu (mu), kappa (kappa) and delta (delta) opioid receptors were ascertained in dog cerebral cortex homogenates. The selective peptides, [3H]D-Pen2-D-Pen5enkephalin [( 3H]DPDPE) and [3H]D-Ala2-MePhe4-Glyol5-enkephalin [3H]Glyol; [3H]DAMGO), bound to delta- and mu-opioid receptors with high affinity (dissociation constants, Kd values = 4.7 and 1.6 nM) but to different densities of binding sites (Bmax values of 49.2 and 6.6 fmol/mg protein, respectively) in washed homogenates of dog cerebral cortex. In contrast, the non-peptides, [3H]U69593 [( 3H]U69) and [3H]etorphine [( 3H]ET), labeled a high concentration of kappa-opioid receptors (respective Bmax values of 67.2 and 76.6 fmol/mg protein) of high affinity (respective Kds of 1.4 and 0.47 nM) in the same tissue homogenates. Thus, the relative rank order of opioid receptor densities was: kappa greater than delta much greater than mu. The selective labeling of the kappa-receptors with two different drugs [( 3H]U69 and [3H]ET) failed to reveal the possible existence of multiple kappa-sites based on the relative Bmax values of the two radioligands. This conclusion was further supported by the similarity of the pharmacological specificity of both [3H]U69 and [3H]ET binding, where all the opioids tested produced 100% inhibition of these labels and where the rank order of potency of opioids at inhibiting the binding of these probes was: U50488 greater than U69593 greater than dynorphin-(1-8) greater than naloxone much greater than morphine much greater than Glyol (DAMGO) greater than DPDPE.(ABSTRACT TRUNCATED AT 250 WORDS)     

Precordial electrocardiographic mapping in the identification of patients with left main stem narrowing

This study was designed to determine if exercise testing using 16-lead precordial mapping can be used to identify patients with left main stem narrowing. In a group of 235 consecutive patients undergoing coronary angiography there were 35 patients with left main stem narrowing. The patients with left main stem disease differed from the others in that not only did they develop extensive S-T segment depression, but more specifically these changes occupied a characteristic position high on the precordium above the usual site of the precordial leads of the 12-lead electrocardiogram. This finding was then tested prospectively in a second group of 100 patients. Fourteen of the 100 patients had left main stem narrowing; the sensitivity and specificity of S- T segment changes high on the precordium in identifying patients with left main stem disease were 82 and 84% respectively. Thus precordial mapping and exercise testing is valuable in the diagnosis of patients with left main stem narrowing. The technique is simple and inexpensive and provides data not available using the conventional precordial leads of the 12-lead electrocardiogram.     

Intermyofibrillar and nuclear-myofibrillar connections in human and canine myocardium. An ultrastructural study

Cytoplasmic filaments, which measure 100 Å in diameter, and which differ morphologically from actin and myosin filaments, are described in normal canine myocardium and in normal and hypertrophied human myocardium. These filaments were found between Z bands, near the sarcolemma, in regions of intercalated discs, and in the vicinity of nuclear membranes. The 100 Å filaments appeared to form transverse connections between adjacent Z bands and between Z bands and outer nuclear membranes. These filaments probably function as a cytoskeleton.     

Gas chromatographic and mass spectrometric studies on urinary organic acids in a patient with congenital lactic acidosis due to pyruvate decarboxylase deficiency.

Detailed studies, using gas chromatography and mass spectrometric methods, of the urinary organic acids excreted by a patient with proven pyruvate decarboxylase deficiency are reported. In addition to the greatly-increased levels of lactate and pyruvate, marked elevation in the levels of 2-oxoglutaric, malic, and isocitric acids were observed, with associated increases 2-hydroxyglutaric, fumaric, succinic, and glyceric acids, and reduced citric acid excretion. The levels of excretion during clinically static and acute periods are compared to those in a normal neonate and normal infants. The metabolites observed indicate a probable defect in the oxidation of pyruvate by pyruvate dehydrogenase and suggest the presence of secondary defects in the tricarboxylic acid cycle. Studies of this type may enable the relatively rapid identification of the probable underlying enzyme deficiency in cases of congenital lactic acidosis, prior to confirmatory enzyme studies.     

腺病毒介导的IL-24基因对胶质瘤细胞系U251拓扑异构酶Ⅱα及Caspase-3表达的影响

目的探讨腺病毒介导的IL-24基因(Ad5F35-hIL-24)对胶质瘤细胞系U251拓扑异构酶Ⅱα(topoⅡα)及Caspase-3表达的影响。方法应用腺病毒载体将IL-24基因转染U251细胞后,采用四甲基偶氮唑盐(MTT)方法观察Ad5F35-hIL-24对U251细胞的抑制作用;Hoechst33258荧光染色,以及流式细胞术测定细胞凋亡;应用免疫组织化学方法检测topoⅡα表达;免疫印迹法检测topoⅡα和Caspase-3蛋白质表达变化;Transwell实验观察Ad5F35-hIL-24对U251细胞侵袭力的影响。结果与对照组相比,Ad5F35-hIL-24对胶质瘤细胞有明显抑制作用,能显著诱导细胞凋亡,且呈浓度依赖性;免疫组织化学法显示,Ad5F35-hIL-24能明显抑制topoⅡα表达;免疫印迹检测表明,topoⅡα表达明显降低,而Caspase-3蛋白的表达水平增加;Transwell实验表明,Ad5F35-hIL-24能明显降低U251细胞的侵袭能力。结论外源性IL-24基因能显著抑制胶质瘤细胞增殖,诱导细胞凋亡;topoⅡα及Caspase-3是其重要的作用靶点。该结果对于IL-24基因用于临床治疗胶质瘤有一定参考意义。     

槲皮素对U937细胞系抑制增殖和诱导凋亡作用的研究

目的 探讨黄酮类化合物槲皮素（Que）对人类单核细胞白血病U937细胞系的抑制增殖和诱导凋亡的作用。方法 应用MTT法检测不同浓度槲皮素对U937细胞的增殖抑制作用；AO／PI荧光染色后倒置荧光显微镜下观察细胞形态学变化；琼脂糖凝胶电泳测定细胞DNA的片段化；应用流式细胞仪检测细胞凋亡率及细胞周期分布。结果槲皮素能明显抑制U937细胞增殖，并存在剂量-效应关系和时间-效应关系；诱导U937细胞出现凋亡所具有的形态学和生化特征；随着槲皮素浓度升高，凋亡细胞和坏死细胞比例增加；将细胞特异性地阻滞在S期，出现凋亡峰。结论 槲皮素能抑制U937细胞增殖，诱导细胞凋亡，并具有细胞周期特异性。     

Effects of 7-OH-DPAT and U 99194 on the behavioral response to hot plate test, in rats

Aim of present study was to investigate in male Wistar rats, whether behavioral response to hot plate test application could be influenced by systemic administration of 7-OH-DPAT, a dopaminergic (DA) D3 versus D2 receptor agonist, or U 99194, a DA D3 versus D2 receptor antagonist. Each trial lasted no more than 10 s and the whole experimental session lasted 120 min. Animal behavior was recorded by means of a digital videocamera and later, frame by frame examined using a professional videorecorder. Latency of each behavioral pattern, characterizing the response, was analysed, showing significant changes only with U 99194. A multivariate cluster analysis indicated the presence of three main behavioral clusters (exploratory, primary responses to pain, escape) which, also, resulted significantly modified by both drugs. In addition, diagrams of preferential direction, obtained through multivariate stochastic analysis, evidenced switching probabilities differences among different patterns and clusters. Results demonstrate that the behavioral response to hot plate test application is altered following 7-OH-DPAT or U 99194 administration. These findings are discussed in terms of a) drugs influence on behavioral switching and learning processes; b) a likely activity on DA D3 versus D2 receptors.     

U5 snRNP在前体mRNA剪接加工中的作用

前体mRNA的剪接是基因表达过程中的关键一步,发生在基因的转录之后与蛋白合成之前。在由前体mRNA剪接加工而形成成熟mRNA时,需要将转录本中的内含子切除,因为它会干扰基因的表达。前体mRNA的剪接发生在细胞核中,是在一个大的RNA与蛋白质的复合体即剪接体的催化下完成的。复合体中含有U1、U2、U5,二聚体形式的U4/U6小核RNA(snRNA)和一些小核核糖核蛋白(snRNP)。U5snRNP特异蛋白包括hPrp8,hSnu114(aGTPase),hBrr2(aDExH/Dboxhelicase)和Prp28等。Prp8构成剪接体的催化核心,hSnu114可避免剪接复合体过早的活化。因此,U5snRNP在剪接体聚集过程和前体mRNA的剪接反应中发挥重要作用。