Synthesis and characterization of (C5H9C9H6)(2)Yb(THF)(2)(II) (1) and [(C5H9C5H4)(2)Yb(THF)](2)O-2 (2), and ring-opening polymerization of lactones with 1

Reaction of YbI2 with two equivalents of cyclopentylindenyl lithium (C5H9C9H6Li) affords ytterbium(II) substituted indenyl complex (C5H9C9H6)(2)Yb(THF)(2) (1) which shows high activity to ring-opening polymerization (ROP) of lactones. The reaction between YbI2 and cyclopentylcyclopentadienyl sodium (C5H9C5H4Na) gives complex [(C5H9C5H4)(2)Yb(THF)](2)O-2 (2) in the presence of a trace amount of O-2, the molecular structure of which comprises two (C5H9C5H4)(2)Yb(THF) bridged by an asymmetric O-2 unit. The O-2 unit and ytterbium atoms define a plane that contains a C-i symmetry center.

POSTSYNAPTIC ALPHA-2 RECEPTOR STIMULATION IMPROVES MEMORY IN AGED MONKEYS - INDIRECT EFFECTS OF YOHIMBINE VERSUS DIRECT EFFECTS OF CLONIDINE

Very low doses (0.00001 mg/kg) of the alpha-2 adrenergic antagonist, yohimbine, improved working memory performance in a subset of aged monkeys. Improvement appeared to result from increased norepinephrine (NE) release onto postsynaptic alpha-2 adrenoceptors, as the response was blocked by the ''postsynaptic'' alpha-2 antagonist, SKF104078. Cognitive-enhancing effects of low dose yohimbine treatment may depend on aged animals retaining an intact, endogenous NE system. In contrast to yohimbine, the alpha-2 agonist, clonidine, has improved working memory in air aged animals examined. In the present study, clonidine's beneficial effects were also blocked by the postsynaptic antagonists SKF104078 and SKF104856, suggesting that clonidine acts by directly stimulating postsynaptic alpha-2 adrenoceptors. Beneficial doses of clonidine (0.01 mg/kg) and yohimbine (0.00001 mg/kg) were combined to see if they would produce additive effects on memory enhancement. This strategy was successful in young monkeys with intact NE systems but was not effective in the aged monkeys. These findings demonstrate that drugs that indirectly stimulate postsynaptic alpha-2 receptors by increasing NE release are not as reliable in aged monkeys as directly acting agonists that can replace NE at postsynaptic alpha-2 receptors.

Morphine induces Beclin 1-and ATG5-dependent autophagy in human neuroblastoma SH-SY5Y cells and in the rat hippocampus

Chronic exposure to morphine can induce drug addiction and neural injury, but the exact mechanism is not fully understood. Here we show that morphine induces autophagy in neuroblastoma SH-SY5Y cells and in the rat hippocampus. Pharmacological approach shows that this effect appears to be mediated by PTX-sensitive G protein-coupled receptors signaling cascade. Morphine increases Beclin 1 expression and reduces the interaction between Beclin 1 and Bcl-2, thus releasing Beclin 1 for its pro-autophagic activity. Bcl-2 overexpression inhibits morphine-induced autophagy, whereas knockdown of Beclin 1 or knockout of ATG5 prevents morphine-induced autophagy. In addition, chronic treatment with morphine induces cell death, which is increased by autophagy inhibition through Beclin 1 RNAi. Our data are the first to reveal that Beclin 1 and ATG5 play key roles in morphine-induced autophagy, which may contribute to morphine-induced neuronal injury.

Localization and distribution of tissue type and urokinase type plasminogen activators and their inhibitors type 1 and 2 in human and rhesus monkey fetal membranes

Fetal membranes consist of 10 distinct layers including components of amnion, chorion and decidua, the latter being of maternal origin. They form mechanically integrated sheets capable of retaining amniotic fluid and play an essential role in protecting fetal growth and development in the pregnant uterus. The extracellular matrix, substrate for plasminogen activators (PAs), is an important supportive framework of the fetal membranes. :Fetal membranes from women with preterm premature rupture of membranes may differ in their protease activity compared with normal membranes. To identify the presence of PAs and their inhibitors (PAI) and their possible role in the process of fetal membrane rupture, this study in investigated the distribution and localization of both protein and mRNA for tissue (t) and urokinase (u) PA and their inhibitors type 1 (PAI-1) and type 2 (PAI-2) in amniochorion of human and rhesus monkey using conventional and. confocal immunofluorescence microscopy. In situ hybridization analysis showed that the distribution and localization of mRNAs for tPA, uPA, PAI-I and PAI-2 were similar in the fetal membranes of human and rhesus monkey; no obvious species difference was observed. Evidence of tPA mRNA was detected in amniotic epithelium, trophoblast cells and nearly all cells of the decidual layer. Strong expression of uPA mRNA was noted in the decidual cells which increased in intensity as the abscission point was approached. Weak staining in chorion laeve trophoblast was also detected. In situ hybridization experiments showed PAI-1 mRNA to be concentrated mainly in the decidual cells, some of which were interposed into the maternal-facing edge of the chorion laeve. Maximal labelling of the decidua occurred towards the zone of abscission. Weak expression of PAI-1 mRNA nas also noted in some cells of the chorion laeve. The distribution of PAI-2 mRNA in amniochorion was also concentrated in the cells of the decidual layer, maximum expression of the mRNA was in the level of abscission. No detectable amount of mRNAs for tPA, uPA, PAI-1 and PAI-2 was found in the fibroblast, reticular and spongy layers. Distribution of the proteins of tPA, uPA and PAI-1 in the fetal membranes of these two species was consistent with the distribution of their mRNA. Anti-PAI-2 immunofluorescence was found to be strongly concentrated in the amniotic epithelium, but PAI-2 mRNA was negative in this layer, suggesting that the epithelium-associated PAI-2 is not of epithelial origin. These findings suggest that a local fibrinolysis in fetal membranes generated by precisely balanced expression of PAs and their inhibitors via paracrine or autocrine mechanisms may play an essential role in fetal membrane development, maturation and in membrane rupture. Following an analysis of the distribution and synthesis of activators and inhibitors it was found that they may play a role in abscission during the third stage of labour. (C) 1998 W. B. Saunders Company Ltd.

Energy level analyses of even-parity J=1 and 2 Rydberg states of Sn I by multichannel quantum defect theory

This paper analyzes the energy levels along the even-parity J=1 and 2 Rydberg series of Sn I by multichannel quantum defect theory. A good agreement between theoretical and experimental energy levels was achieved. Below 59198 cm~(-1), a total of 85 and 23 new energy levels, respectively, in the J=1 and J=2 series, which cannot be measured previously by experiments, are predicted in this work. Based on the calculated admixture coefficients of each channel, interchannel interactions were discussed in detail. The results are helpful to understand the characteristics of configuration interaction among even-parity levels in Sn I.

Interactions of thiamine monophosphate (TMP) with one- and two-dimensional polymeric halogenomercurate anions. Crystal structures of (TMP)(Hg2Br5)center dot 0.5H(2)O and (TMP)(2)(Hg3I8)

An investigation into the interactions between thiamine monophosphate (TMP) and anions has resulted in the preparation and X-ray characterization of the compounds (TMP)(Hg2Br5).0.5H(2)O (1) and (TMP)(2)(Hg3I8) (2). In each compound the TMP molecule exists as a monovalent cation in the usual F conformation. The halogenomercurate anions occur in two-dimensional (2-D) network in 1 or one-dimensional (1-D) chain in 2. In both 1 and 2, the structures consist of alternating cationic sheets of the hydrogen-bonded TMP molecules and anionic sheets of the polymeric halogenomercurate anions. The TMP molecule binds to the polymeric anions through the characteristic 'anion bridge I', C(2)-H..X...pyrimidinium (X = Br in 1 and 1 in 2), and electrostatic interactions between electropositive S(1) and halogen atoms. The 'anion bridge II' of the type N(4'1)-H...X...thiazolium (X = phosphate group) plays a role in stabilizing the molecular conformation. The biological implication of the host-guest-like complexation between TMP and polymeric anions is discussed.

Syntheses and crystal structures of [(C6H5CH2C5H4)(2)GdCl center dot THF](2) and (C6H5CH2C5H4)(2)ErCl center dot THF

[(C6H5CH2C5H4)(2)GdCl . THF](2) (1) and (C6H5CH2C5H4)(2)ErCl . THF (2) were prepared by the reaction of LnCl(3) (Ln=Gd, Er) with benzylcyclopentadienyl sodium in THF and characterized by elemental analysis, IR, H-1 NMR, C-13 NMR, MS and thermal gravimetry. The crystal structures of both compounds were determined. Complex 1 is dimeric and its structure belongs to the monoclinic, P2(1)/c space group with a=1.1432(2), b=1.2978(2), c=1.7604(3) nm, beta=108.75(2), V=2.4732(9) nm(3), Z=2(four monomers), D-c=1.54 g . cm(-3). R=0.0342 and R(w)=0.0362. Complex 2 is monomer and its structure belongs to the orthorhombic, P2(1)2(1)2(1) space group with a=0.8645(2), b=1.1394(3), c=2.5289(4) nm, V=2.4919(9) nm(3), Z=4, D-c=1.56 g . cm(-3). R=0.0514, R(w)=0.0529. The determination of the crystal structure shows that in complex 1 the benzyl groups on the cyclopentadienyls coordinated to Gd3+ are located in the opposite direction (139 degrees); in complex 2 the benzyl groups on the cyclopentadienyls coordinated to Er3+ are located in the same direction (6.5 degrees).

Sol-gel-derived alpha(2)-K7P2W17VO62/graphite/organoceramic composite as the electrode material for a renewable amperometric hydrogen peroxide sensor

The conductive alpha (2)-K7P2W17VO62/graphite/organoceramic composite was prepared by dispersing alpha (2)-K7P2W17VO62 and graphite powder in a propyltrimethoxysilane-based sol-gel solution; it was used as the electrode material for an amperometric hydrogen peroxide sensor. The modified electrode had a homogeneous mirror-like surface and showed well defined cyclic voltammograms. Square-wave voltammetry was employed to study the pH-dependent electrochemical behavior of c alpha (2)-K7P2W17VO62 doped in the graphite organoceramic matrix, and the experiment showed that both protons and sodium cations participated in the odor process. A hydrodynamic voltammetric experiment was performed to characterize the electrode as an amperometric sensor for the determination of hydrogen peroxide. The sensor can be renewed easily in a repeatable manner by a mechanical polishing step and has a long operational lifetime. (C) 2000 Elsevier Science B.V. All rights reserved.

RESERPINE IMPAIRS SPATIAL WORKING-MEMORY PERFORMANCE IN MONKEYS - REVERSAL BY THE ALPHA-2-ADRENERGIC AGONIST CLONIDINE

Repeated daily treatment with the catecholamine-depleting agent, reserpine, dramatically reduced performance on the delayed response task, a test of spatial working memory that depends upon the integrity of the prefrontal cortex. Delayed response performance fell from an average of 27.2/30 trials correct before reserpine treatment to an average of 20.4/30 trials correct after repeated reserpine administration. Injection of the alpha2-adrenergic agonist, clonidine (0.0001-0.05 mg/kg), to chronic reserpine-treated monkeys significantly restored performance on the delayed response task; performance after an optimal dose averaged 27.8/30 trials correct. Clonidine's beneficial effects on delayed response performance were longlasting; monkeys remained improved for more than 24 h after a single clonidine injection. The finding that clonidine is efficacious in reserpinized animals supports the hypothesis that alpha2-adrenergic agonists improve cognitive function through actions at postsynaptic, alpha2-adrenergic receptors on non-adrenergic cells. In contrast to the delayed response task, reserpine had little effect on performance of a visual discrimination task, a reference memory task which does not depend on the prefrontal cortex. These results emphasize the importance of postsynaptic alpha2-adrenergic mechanisms in the regulation of working memory,

树（左鼠右句）前额叶皮层神经元信息处理功能的alpha-2去甲肾上腺素能受体机制研究

本研究采用微电极胞外记录技术和微电泳技术探讨了树（左鼠右句）前额叶神经元的电生理及其alpha-2去甲肾上腺素能受体的性质发现：1.树（左鼠右句）前额叶神经元的自发放电以中频(1-10次/秒)为主。2.树（左鼠右句）前额叶存在多模和单模感觉相关神经元。3.树（左鼠右向）前额叶存在clonidine敏感神经元。4.在树（左鼠右向）前额叶多模神经元中，有较高比例的clonidine敏感神经元。本研究提示：树（左鼠右句）前额叶的clonidine敏感神经元大多为单模和多模神经元。推测这些感觉相关神经元的信息处理功能可能与alpha-2受体有关。此外，本研究表明树（左鼠右句）前额叶神经元电活动具有前额叶的特征。

Synthesis and structure of molybdenum-citrato cluster mu(2)-S bridge

A new molybdenum-citrato cluster containing [Mo2O2(mu-S)(2)(C6H5O7)(C6H4O7)](5-) anion was synthesized and characterized by elemental analysis, IR, UV-Vis spectra, XPS and X-ray diffraction. The parameters of the crystal structure of the compound are monoclinic, space group P2(1)/c, a = 2. 376 6(5) nm, b = 1. 327 4(3) nm, c = 2. 247 1(5) nm, beta = 118. 21 degrees, V = 6. 247(2) nm(3), Z = 8, D-c = 2. 128 g/cm(3), F(000) = 3 984, mu = 1 694 cm(-1), R = 0. 083 1 and R-2,R-w = 0. 154 9. The anion is binuclear molybdenum-citrato complex with mu(2)-S bridge. Each molybdenum atom pocesesses a distorted octahedral struture, which is coordinated with a terminal oxygen, two sulfur atoms, three oxygen atoms of hydroxyl, alpha-carboxylate, beta-carboxylate from citrate.

Interaction between single molecules of Mac-1 and ICAM-1 in living cells: An atomic force microscopy study

The interaction between integrin macrophage differentiation antigen associated with complement three receptor function (Mac-1) and intercellular adhesion molecule-1 (ICAM-1), which is controlled tightly by the ligand-binding activity of Mac-1, is central to the regulation of neutrophil adhesion in host defense. Several "inside-out" signals and extracellular metal ions or antibodies have been found to activate Mac-1, resulting in an increased adhesiveness of Mac-1 to its ligands. However, the molecular basis for Mac-1 activation is not well understood yet. In this work, we have carried out a single-molecule study of Mac-1/ICAM-1 interaction force in living cells by atomic force microscopy (AFM). Our results showed that the binding probability and adhesion force of Mac-1 with ICAM-1 increased upon Mac-1 activation. Moreover, by comparing the dynamic force spectra of different Mac-1 mutants, we expected that Mac-1 activation is governed by the downward movement of its alpha 7 helix. (c) 2007 Elsevier Inc. All rights reserved.

Trichosanthin suppresses the elevation of p38 MAPK, and Bcl-2 induced by HSV-1 infection in Vero cells

Trichosanthin (TCS) is a type I ribosome-inactivating protein (RIP) effective against HIV-1 and HSV-1 replication. The mechanism of its antiviral activity is not clear. Many believe that it is related to ribosome inactivation. Some RIPs and viral infectio

Immunolocalization and expression of vascular endothelial growth factor receptors (VEGFRs) and neuropilins (NRPs) on Keratinocytes in human epidermis

Vascular endothelial growth factor (VEGF) plays an important role in normal and pathological angiogenesis. VEGF receptors (VEGFRs, including VEGFR-1, VEGFR-2, and VEGFR-3) and neuropilins (NRPs, including NRP-1 and NRF-2) are high-affinity receptors for V