bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Chronic Consumption of Ethanol on the Redox State of the Rat Liver
Authors: Gordon Ellen R.
Published: December 2009

Isocaloric replacement of the carbohydrate content of the diet by ethanol (36% of the total caloric intake) produced fatty infiltration and a reduced redox potential of the liver. The hepatic ratio of NAD+/NADH was 1.2 in the ethanol-treated group compared to 8.6 in the pair-fed control group. This change was associated with the consumption of ethanol as, 24 h after the removal of ethanol from the liver, the ratio had returned to the level of the control group. The hepatic substrate levels of NAD+-linked lactate dehydrogenase and the NAD+-linked β-hydroxybutyrate dehydrogenase systems were measured and used to calculate the NAD+/NADH ratio of the cytoplasm and mitochondria, respectively. The chronic consumption of ethanol did not alter the ratio in the cytoplasm but did shift the ratio in the mitochondria to one-fourth that observed in the control group. Twenty-four hours after ethanol was removed from the diet, this reduced redox potential in the mitochondria shifted to a level higher than that observed in the control groups.
Synthesis of Amino Acids from Succinate by the Mitochondria of Neurospora crassa
Authors: LaBrie D. A. , Leiter E. H. , Bergquist A. , Wagner R. P.
Published: December 2009

The synthesis of valine by isolated Neurospora mitochondria in the presence of pyruvate is increased more than twofold when the cofactor assay mixture consisting of NADP, thiamine pyrophosphate (TPP), glucose-6-phosphate, and pyridoxal phosphate, and the respiring assay mixture containing ADP, orthophosphate, and succinate are combined. Although no single component of the cofactor mixture is completely responsible for the increase in valine synthesis, addition of TPP to the respiring assay mixture has the greatest effect.Neurospora mitochondria are able also to synthesize valine when pyruvate and glucose-6-phosphate are omitted from the combined mixtures. The succinate, a component of the respiring mixture, is the carbon source for the synthesis of valine, alanine, and glutamic acid. However, these syntheses require the addition of succinate, NADP, and TPP only. Addition of ADP and orthophosphate has no effect on the amounts of amino acids synthesized from succinate. Provisional evidence is presented that the source of pyruvate used in such syntheses is succinate-derived malate which is then converted to pyruvate by a mitochondrial decarboxylating malate dehydrogenase ("malic" enzyme).
Phosphonolipids. XXV. Synthesis of α-Octadecyl-β-hexadecanoyl-L-α-glyceryl- (2-aminoethyl)phosphonate, a Homologue of an α-Monoether- phosphonocephalin Occurring in Tetrahymena pyriformis
Authors: Baer Erich , Basu Hemendra
Published: December 2009

The α-monoether-phosphonocephalin isolated by Thompson and Woo from Tetrahymena pyriformis was shown to possess the L-configuration. A homologue of the natural compound, vis. α-octadecyl-β-hexadecanoyl-L-α-glyceryl-(2-aminoethyl)phosphonate, has been synthesized. It was obtained via the following series of intermediate compounds: L-acetone glycerol → D-octadecylglycerol → α-trityl-D-octadecylglycerol → α-trityl-β-hexadecanoyl-D-octadecylglycerol → β-hexadecanoyl-D-octadecylglycerol → α-octadecyl-β-hexadecanoyl-L-α-glyceryl-(2-phthalimidoethyl)phosphonate.
Evidence for Two CMP-N-acetylneuraminic Acid: Lactose Sialyltransferases in Rat, Porcine, Bovine, and Human Liver
Authors: Hudgin R. L. , Schachter Harry
Published: December 2009

Evidence is presented for two sialyltransferases catalyzing formation of sialyl-(2 → 3)-lactose and sialyl-(2 → 6)-lactose in fetal and adult livers from rats, pigs, beef, and humans. In rat and porcine liver, the ratio of the rates of formation of these products varied with age. This ratio also varied with the pH of incubation for all four species. The implications of these findings in the control of glycoprotein biosynthesis are discussed.
Bovine Thyroid Microsomal Monoamine Oxidase
Authors: Mushahwar Isa K. , Oliner Leo , Schulz Arthur R.
Published: December 2009

Monoamine oxidase has been isolated and purified from bovine thyroid microsomes. The general characteristics and steady-state kinetic behavior of the microsomal enzyme have been compared with those of the enzyme isolated from bovine thyroid mitochondria. The enzymes from the two sources exhibit a high degree of substrate specificity with respect to the amines oxidized. 3-Iodotyramine is a noncompetitive inhibitor of tyramine oxidation in the case of both the mitochondrial and microsomal enzymes. Product inhibition studies suggest that the enzymes from mitochondria and microsomes catalyze reactions which proceed by a similar pathway. In contrast to the mitochondrial enzyme, the enzyme isolated from microsomes is susceptible to inhibition by anions in the following order; [Formula: see text].
Regulation of Chloramphenicol Synthesis in Streptomyces sp. 3022a. Branch-Point Enzymes of the Shikimic Acid Pathway
Authors: Lowe D. A. , Westlake D. W. S.
Published: December 2009

The pattern of induction and regulatory properties of the enzymes chorismate mutase, prephenate dehydratase, and anthranilate synthetase were investigated in a chloramphenicol-producing Streptomycete under a variety of environmental conditions. The enzymes were not subject to repression by intermediates or end products of the shikimic acid pathway. Throughout purification procedures chorismate mutase and prephenate dehydratase activities were each represented by single enzyme proteins of molecular weights 75 000 and 220 000, respectively. Chorismate mutase activity was not inhibited by end products or intermediates of the shikimic acid pathway. Prephenate dehydratase activity was controlled solely by feedback inhibition by L-phenylalanine, and anthranilate synthetase activity was only inhibited by L-tryptophan.
Homology and Relatedness of Amino Acid Interchanges in the Variable Region of κ Light Chains from Human Immunoglobulins
Authors: Percy M. E. , Percy J. R.
Published: December 2009

We have devised a method for assessing the relatedness of amino acid interchanges in the variable regions of immunoglobulin polypeptide chains, in terms of the nature of the differences between trinucleotide codons. We have used it to construct a map of the average human κ chain showing the positions which (i) give the chain κ identity, (ii) give the chain subgroup identity within the κ type, (iii) give the chain identity within a subgroup, and (iv) are invariant. In order to determine the positions at which the interchanges are homologous, we have performed a second analysis using the assumption that functionally equivalent amino acids are identical.κ Identity was found throughout the amino-terminal half of the chain (positions 1–108, the variable region). Subgroup identity was not found beyond invariant Phe 98, but was very pronounced in the first 22 positions of the chain. κ and subgroup identity were evident within hypervariable regions (positions 27–35, 48–52, and 90–97), however. A high degree of functional homology was found in the 11 residues at the end of the variable region and at certain individual positions scattered throughout the variable region, but not in the hypervariable regions.The distribution of these different classes of positions might reflect the distribution of certain functions within the chains.
L-Asparaginase from the BCG Strain of Mycobacterium bovis. I. Purification and In Vitro Immunosuppressive Properties
Authors: Soru Eugenia , Teodorescu M. , Zaharia Odette , Szabados Judith , Rudescu Karin
Published: December 2009

L-Asparaginase isolated from the BCG strain of Mycobacterium bovis has been purified approximately 100-fold by negative adsorption on Ca-phosphate gel, batchwise adsorption and column chromatography on DEAE-Sephadex, gel filtration through Bio Gel P-200, and crystallization.The final enzyme preparation appeared to be pure on the basis of cellulose acetate and polyacrylamide gel electrophoresis, immunodiffusion, and immunoelectrophoresis in agar gel.Inhibition by crystalline BCG L-asparaginase of blast cell transformation was demonstrated by means of thymidine-3H incorporation in phytohemagglutinin-stimulated rabbit spleen cell cultures. This effect was not observed with heat-inactivated enzyme.Antibody synthesis in spleen cell cultures which were secondarily stimulated in vitro with polio virus was also depressed.Intradermal inoculation of crystalline BCG L-asparaginase in BCG-sensitized guinea pigs gave no significant tuberculin type reaction.
Reduction of Folate and Dihydrofolate by Dithionite
Authors: Kawai M. , Scrimgeour K. G.
Published: December 2009

Sodium dithionite reduces folate to 7,8-dihydrofolate at room temperature, but further reduction to the tetrahydro level can be obtained at elevated temperatures (11). Both folate and dihydrofolate form adducts with dithionite (presumably sulfinates), and these adducts appear to be intermediates in the reduction processes. The adduct of dihydrofolate is not converted to tetrahydrofolate at low temperatures, and is thus more amenable to examination. The mechanism of reduction of the folate compounds and of the nicotinamide ring by dithionite involves nucleophilic attack by the dithionite, not a free radical reduction as with p-nitrophenol. The rate of addition of bisulfite to folate and dihydrofolate has been measured by the stopped-flow kinetic method, and the nonenzymic and enzyme-catalyzed addition of nucleophiles to folate compounds is discussed.
Quelques aspects de la synthèse protéique dans les muscles thoraciques en développement de Schistocerca gregaria (Forsk.)
Authors: Richard C. , Chaudhary K. D.
Published: December 2009

Polysomes obtained from the postmitochondrial fraction of the thoracic muscles undergo disassociation into monomers when treated with pancreatic RNase. In contrast, the preparations obtained from microsomes on RNase treatment result in the association of monomers into heavier aggregates. A combined treatment with trypsin, however, renders the polysomes sensitive to RNase action. Characteristics of a cell-free amino acid incorporation system have been described and compared with similar systems obtained from other organisms or tissues. GTP seems to reverse the inhibition caused by cycloheximide. Amino acid incorporation capacity of the microsomal and ribosomal fractions prepared from the thoracic muscles at different stages of development was investigated in the presence and absence of added poly U. Both the microsomal and ribosomal preparations respond to the addition of poly U. However, the ribosomes require higher concentrations of this copolymer for attaining full saturation. The significance of the findings reported in this investigation is discussed.
Selective Inhibition of Hemoglobin Formation in Chick Embryo Blood Islands by Chloramphenicol
Authors: Wainwright S. D. , Wainwright Lillian K. , Fraser I. H.
Published: December 2009

Chloramphenicol markedly inhibited the formation of hemoglobin by chick blastodiscs explanted before the 8-somite stage of development onto minimal or egg homogenate medium. Sensitivity to inhibition of hemoglobin formation was reduced at the 8-somite stage. Chloramphenicol had no effect upon the incorporation of leucine into total protein, and only slightly inhibited the cycloheximide-resistant incorporation of leucine.
Lipid Composition and Synthesis in the Muscles of Normal and Dystrophic Chickens
Authors: Chio Lee Foon , Peterson D. W. , Kratzer F. H.
Published: December 2009

The lipids of the superficial pectoral muscle of 5-week-old normal and dystrophic New Hampshire chickens were fractionated by thin-layer chromatography procedures. Total lipid in the dystrophic muscle was fivefold greater than in normal muscle with the triglycerides 15-fold greater and the phospholipids 1.5-fold greater (wet weight basis). The relative proportions of phospholipids were quite similar except for significantly less phosphatidylcholine and phosphatidic acid in the dystrophic muscle. In another study acetate-2-14C was injected intraperitoneally into normal and dystrophic chickens which were killed at various times up to 7 days after the administration. The dystrophic birds incorporated acetate-2-14C to a greater extent into total lipids, triglycerides, and phospholipids of the muscle than normal chickens. The turnover times for both triglycerides and phospholipids were much greater in dystrophic than in normal chickens with the triglycerides showing a longer time than the phospholipids. In vitro incubation of acetate-2-14C with muscle slices showed a greater rate of incorporation into lipid by dystrophic than by normal muscle. These results indicate that the difference in acetate incorporation between normal and dystrophic muscle was due to metabolism in the muscle itself and not entirely a result of mobilization of lipid from other tissues.
Kinetics of the Reaction of Nitrous Acid with Model Compounds and Proteins, and the Conformational State of N-terminal Groups in the Chymotrypsin Family
Authors: Kurosky A. , Hofmann T.
Published: December 2009

The kinetics of the reaction of nitrous acid at 4° and pH 4.0 with various amino acids, peptides, and proteins were studied. The reaction with isoleucine methyl ester was found to have a linear dependence on the square of the HONO concentration showing that N2O3 was the reactive species. Third order nitrosation rate constants of primary amino groups showed a correlation with their pK values. They were calculated for the concentration of the unprotonated species to give intrinsic reactivities. The rate of nitrosation of acetyltryptophan to give N-nitrosoacetyltryptophan was found to be a linear function of the nitrous acid concentration. This nitrosation therefore follows a different mechanism. The reaction of nitrous acid with tyrosine residues was examined by spectrophotometry. The reaction was negligible compared to that of other groups. Acetylhistidine and imidazole did not react. Reactivities for α-amino groups, ε-amino groups, and other residues in proteins were compared. The conformational state of the N-terminal residues in serine proteinases, as revealed from their reactivities, is discussed in detail. It is concluded that nitrous acid reacts preferentially with "surface" residues and is a useful tool for exploring conformational states of reactive groups in proteins, especially α-amino groups and indole rings.
Penicillocarboxypeptidase-S, a Nonspecific SH-Dependent Exopeptidase
Authors: Jones S. R. , Hofmann T.
Published: December 2009

An extracellular carboxypeptidase with a pH optimum of between 4 and 5 has been isolated from the culture medium of Penicillium janthinellum. Like penicillopepsin, this enzyme is only released when the stationary phase of growth is reached. The enzyme has been purified by affinity chromatography on phenylbutylamine-Sepharose followed by isoelectric focusing. The enzyme was found to be present in two forms with isoelectric points of 3.70 and 3.77. It has a molecular weight of about 48 000 and is inhibited by 10−7 M p-hydroxymercury benzoic acid. It is not inhibited by the metal chelators EDTA, o-phenanthroline, and 8-hydroxyquinoline, or by diisopropyl phosphorofluoridate. The presence of a single cysteine residue has been demonstrated by labelling the enzyme with 14C-iodoacetic acid. The action of the enzyme on glucagon, the S-sulfo-B-chain of insulin, and on penicillopepsin at pH 4.7 shows that it is a nonspecific carboxypeptidase and releases C-terminal proline, lysine, and arginine, as well as the other amino acids. Glycine appears to be the slowest residue to be released. Carbobenzoxy-L-glutamyl-L-tyrosine, the substrate used for routine assays, is hydrolyzed very rapidly. The enzyme also slowly hydrolyzed Leu–Phe, and splits glycine from Leu–Gly–Gly.A second enzyme with carbobenzoxy-L-glutamyl-L-tyrosine activity is present in the growth medium. It has an isoelectric point of 4.72 on an isoelectric focusing column. Preliminary inhibition studies of a partially purified preparation suggest that it differs from the other enzyme.
The Amino Acid Sequence of Cytochrome c-553 from the Chrysophycean Alga Monochrysis lutheri
Authors: Laycock M. V.
Published: December 2009

The amino acid sequence of cytochrome c-553, an electron carrier in the photosynthetic apparatus of the unicellular alga Monochrysis lutheri, has been determined. The protein consists of a single polypeptide chain of 83 amino acid residues. The sequence shows homology with mitochondrial cytochrome c at each end of the chain. The N-terminal glycine is not acetylated and corresponds to position 1 of mammalian cytochrome c when the cysteine residues of the two proteins are aligned.
Purification of Isoenzyme and Coenzymes for Kinetic Study of Horse Liver Alcohol Dehydrogenase
Authors: Gurr Patricia A. , Bronskill Patricia M. , Hanes Charles S. , Wong J. Tze-Fei
Published: December 2009

The isoenzymic forms of the alcohol dehydrogenase (EC 1.1.1.1) of horse liver have been separated by chromatography on carboxymethylcellulose column and identified in terms of their electrophoretic mobilities in the starch gel. Purified isoenzyme fraction C1, which was highest in both total and specific activities, was stable toward rechromatography on carboxymethylcellulose, electrophoresis in starch gel, as well as storage in solution. It therefore satisfied the requirements for use in kinetic studies on the reaction mechanism of the enzyme. Toward the same end, procedures are also described for preparing purified NAD+ and NADH in solution forms which were stable in storage for several days.
Kinetic Mechanism for the Major Isoenzyme of Horse Liver Alcohol Dehydrogenase
Authors: Hanes Charles S. , Bronskill Patricia M. , Gurr Patricia A. , Wong J. Tze-Fei
Published: December 2009

The reaction mechanism for the major isoenzyme C1 of the alcohol dehydrogenase (EC 1.1.1.1) of horse liver has been established through kinetic analysis utilizing direct correlations between rate and mechanistic features. The mechanism consists of random sequences of reaction of the enzyme with ethanol and NAD, and an obligatory sequence of reaction with NADH and acetaldehyde. At high concentrations of ethanol or NADH, excess-ethanol and excess-NADH pathways become evident involving the formation of an enzyme/NADH/ethanol complex. Even after dissociation of NADH from this complex the enzyme/ethanol complex remains imprinted with an altered conformation and differs from the regular binary complex formed under conditions of low ethanol concentrations. A range of elementary rate constants pertaining to the binding and dissociation of reactants from binary as well as ternary complexes of the mechanism has been estimated by means of a combination of algebraic analysis, curve simulation, and sensitivity analysis.
ON THE SIGNIFICANCE OF THE WEYL CURVATURE IN A RELATIVISTIC COSMOLOGICAL MODEL
Authors: DANEHKAR ASHKBIZ
Published: December 2009

The Weyl curvature includes the Newtonian field and an additional field, the so-called anti-Newtonian. In this paper, we use the Bianchi and Ricci identities to provide a set of constraints and propagations for the Weyl fields. The temporal evolutions of propagations manifest explicit solutions of gravitational waves. We see that models with purely Newtonian field are inconsistent with relativistic models and obstruct sounding solutions. Therefore, both fields are necessary for the nonlocal nature and radiative solutions of gravitation.
LOWEST LYING 2+ AND 3- STATES OF Z-EVEN N = 50 ISOTONES IN RELATIVISTIC QUASIPARTICLE RANDOM PHASE APPROXIMATION
Authors: ANSARI A. , RING P.
Published: December 2009

We have studied the variation of the excitation energy, electric multipole decay rate and g factor of the lowest lying 2+ and 3- states of even-ZN = 50 isotones as a function of the mass number in relativistic quasiparticle random phase approximation. Overall agreement with the available data is quite satisfactory considering the wide range of the number of nuclei and their excitation properties in a microscopic approach having no free adjustable parameter. Also predictions are made for several nuclei. We find that increase in the pairing interaction strength, in general, improves the agreement with the data for 3- states but it affects adversely the results for the 2+ states.
THE EFFECT OF METAL-MOLECULE NANO-CONTACTS WITH DIFFERENT END GROUPS IN MOLECULAR ELECTRONICS
Authors: JALILI SEIFOLLAH , PANGH ABDOLHAKIM
Published: December 2009

We investigated the electron transport properties of thiophen-bithiol-based molecular wires through atomic metal–thiophen–metal systems using the first principle methods. Various metal–thiophen–metal atomic systems are constructed with different end atoms (S, Se, and Te). The electron transport of the atomic system is systematically studied by analysis of transmission function, density of states, and current–voltage characteristics of the systems.
ON QUANTUM BRST COHOMOLOGY
Authors: BENTALHA Z. , TAHIRI M.
Published: December 2009

Within bicovariant differential calculi framework, the BRST operator Ω is constructed. We showed that Ω is nil-potent (Ω2=0).
THERMAL-ELASTIC BEHAVIORS OF STAGGERED COMPOSITES
Authors: YANG FAN , FANG DAI-NING , LIU BIN , WANG CHANG-AN
Published: December 2009

A theoretical model is developed to predict the Coefficient of Thermal Expansion (CTE) and thermal mismatch stress of composites with staggered hard platelets in parallel alignment in a soft matrix. The theoretical predictions agree well with the Finite Element Method (FEM) simulations. The results show that different from sandwich composites, the effective CTEs of staggered composite can be tailored by adjusting the aspect ratio of reinforced platelets even with the same volume fraction, which makes the staggered composites more thermal-elastically compatible with the neighboring structures or materials. Moreover, the thermal mismatch stress in the two phases of staggered composite can be reduced through designing microstructure geometry parameters. The staggered composites therefore may have potential application in thermal protections.
DISSIPATIVE PARTICLE DYNAMICS: INTRODUCTION, METHODOLOGY AND COMPLEX FLUID APPLICATIONS — A REVIEW
Authors: MOEENDARBARY E. , NG T. Y. , ZANGENEH M.
Published: December 2009

The dissipative particle dynamics (DPD) technique is a relatively new mesoscale technique which was initially developed to simulate hydrodynamic behavior in mesoscopic complex fluids. It is essentially a particle technique in which molecules are clustered into the said particles, and this coarse graining is a very important aspect of the DPD as it allows significant computational speed-up. This increased computational efficiency, coupled with the recent advent of high performance computing, has subsequently enabled researchers to numerically study a host of complex fluid applications at a refined level. In this review, we trace the developments of various important aspects of the DPD methodology since it was first proposed in the in the early 1990's. In addition, we review notable published works which employed DPD simulation for complex fluid applications.
STRONGLY BAER AND STRONGLY QUASI-BAER SEMIRINGS AND GENERALIZATIONS
Authors: Gupta V. , Chaudhari J. N. , Kumar P.
Published: December 2009

In this paper we study strongly Baer semirings, strongly quasi-Baer semirings and generalizations. We extend the results of ([3], [11], [13], [14], [15]) to noncommutative semirings with identity element 1 ≠ 0.
AN ESTIMATION OF YOUNG INEQUALITY
Authors: Jakšetić J. , Pečarić J.
Published: December 2009

In this paper we give an extension of Young inequality establishing lower and upper bound.
ON THE REGULARITY OF SETS OF MULTI-ACCEPTED STRINGS OF A NON-DETERMINISTIC FINITE AUTOMATON
Authors: Waters L. K. , Grieshop J. K.
Published: December 2009

In this paper we establish the regularity of various sets of multi-accepted strings of nondeterministic finite automata. Regularity follows from the existence of accepting automata constructed by introducing a vector labeling method which generalizes the subset labeling approach. In each set the acceptance levels of the strings correspond to finite sets of additive equivalence classes of non-negative integers.
NHE3 function and phosphorylation are regulated by a calyculin A-sensitive phosphatase
Authors: Dynia Diane W. , Steinmetz Amy G. , Kocinsky Hetal S.
Published: December 2009

Na+/H+exchanger 3 (NHE3) is phosphorylated and regulated by multiple kinases, including PKA, SGK1, and CK2; however, the role of phosphatases in the dephosphorylation and regulation of NHE3 remains unknown. The purpose of this study was to determine whether serine/threonine phosphatases alter NHE3 activity and phosphorylation and, if so, at which sites. To this end, we first examined the effects of calyculin A [a combined protein phosphatase 1 (PP1) and PP2A inhibitor] and okadaic acid (a PP2A inhibitor) on general and site-specific NHE3 phosphorylation. Calyculin A induced a phosphorylation-dependent NHE3 gel mobility shift and increased NHE3 phosphorylation at serines 552 and 605. No change in NHE3 phosphorylation was detected after okadaic acid treatment. An NHE3 gel mobility shift was also evident in calyculin A-treated COS-7 cells transfected with either wild-type or mutant (S552A, S605G, S661A, S716A) rat NHE3. Since the NHE3 gel mobility shift occurred despite mutation of known phosphorylation sites, novel sites of phosphorylation must also exist. Next, we assayed NHE3 activity in response to calyculin A and okadaic acid and found that calyculin A induced a 24% inhibition of NHE3 activity, whereas okadaic acid had no effect. When all known NHE3 phosphorylation sites were mutated, calyculin A induced a stimulation of NHE3 activity, demonstrating a functional significance for the novel phosphorylation sites. Finally, we established that the PP1 catalytic subunit can directly dephosphorylate immunopurified NHE3 in vitro. In conclusion, our data demonstrate that a calyculin A-sensitive phosphatase, most likely PP1, is involved in the regulation and dephosphorylation of NHE3 at known and novel sites.
Facilitation of Postural Limb Reflexes With Epidural Stimulation in Spinal Rabbits
Authors: Musienko P. E. , Zelenin P. V. , Orlovsky G. N. , Deliagina T. G.
Published: December 2009

It is known that after spinalization animals lose their ability to maintain lateral stability when standing or walking. A likely reason for this is a reduction of the postural limb reflexes (PLRs) driven by stretch and load receptors of the limbs. The aim of this study was to clarify whether spinal networks contribute to the generation of PLRs. For this purpose, first, PLRs were recorded in decerebrated rabbits before and after spinalization at T12. Second, the effects of epidural electrical stimulation (EES) at L7 on the limb reflexes were studied after spinalization. To evoke PLRs, the vertebrate column of the rabbit was fixed, whereas the hindlimbs were positioned on the platform. Periodic lateral tilts of the platform caused antiphase flexion–extension limbs movements, similar to those observed in intact animals keeping balance on the tilting platform. Before spinalization, these movements evoked PLRs: augmentation of extensor EMGs and increase of contact force during limb flexion, suggesting their stabilizing postural effects. Spinalization resulted in almost complete disappearance of PLRs. After EES, however, the PLRs reappeared and persisted for up to several minutes, although their values were reduced. The post-EES effects could be magnified by intrathecal application of quipazine (5-HT agonist) at L4–L6. Results of this study suggest that the spinal cord contains the neuronal networks underlying PLRs; they can contribute to the maintenance of lateral stability in intact subjects. In acute spinal animals, these networks can be activated by EES, suggesting that they are normally activated by a tonic supraspinal drive.
Role of Neurotransmitter Receptors in Mediating Light-Evoked Responses in Retinal Interplexiform Cells
Authors: Jiang Zheng , Shen Wen
Published: December 2009

Interplexiform (IP) cells are a long-neglected group of retinal neurons the function of which is yet to be determined. Anatomical study indicates that IP cells are located in the inner nuclear layer, juxtaposed with the third-order neurons. However, the synaptic transmission of IP cells in the inner retina is poorly understood. Using whole cell patch-clamp and pharmacological techniques, we extensively studied synaptic receptors in IP cells. The IP cells in amphibian retinal slices were identified by electrical and morphological properties with voltage-clamp recording and Lucifer yellow dialysis. We find that light-evoked excitatory postsynaptic currents (L-EPSCs) are mediated by AMPA and N-methyl-d-aspartate receptors in IP cells. Although both receptors contributed to the amplitude and kinetics of L-EPSCs, AMPA receptor desensitization substantially shaped L-EPSCs in the neurons, similar to those found in the third-order neurons. The light-evoked inhibitory postsynaptic currents (L-IPSCs) in IP cells were primarily mediated by strychnine-sensitive glycine receptors with a small component of GABAC receptors. GABAC receptor ρ2 subunits were detected in IP cells with single-cell RT-PCR assays. Expression of GABAC receptors is one of the special features for IP cells, distinct from most of the third-order neurons that depend on GABAA and glycine receptors to relay the inhibitory signals. However, GABAA receptors in IP cells acted like nonsynaptic receptors that were activated by exogenous GABA application. Furthermore, L-IPSCs in IP cells were inhibited by the serial inhibitions between amacrine cells in the inner retina. In addition, application of neurotransmitters on the axon terminals of IP cells had no significant current generated in the cells, indicating that the synaptic inputs of IP cells are mainly from the inner retina. This study demonstrates the important role that light signals are encoded by both experiment of inhibitory receptors in IP cells.
A Contribution of Area 5 of the Posterior Parietal Cortex to the Planning of Visually Guided Locomotion: Limb-Specific and Limb-Independent Effects
Authors: Andujar Jacques-Étienne , Lajoie Kim , Drew Trevor
Published: December 2009

We tested the hypothesis that area 5 of the posterior parietal cortex (PPC) contributes to the planning of visually guided gait modifications. We recorded 121 neurons from the PPC of two cats during a task in which cats needed to process visual input to step over obstacles attached to a moving treadmill belt. During unobstructed locomotion, 64/121 (53%) of cells showed rhythmic activity. During steps over the obstacles, 102/121 (84%) of cells showed a significant change of their activity. Of these, 46/102 were unmodulated during the control task. We divided the 102 task-related cells into two groups on the basis of their discharge when the limb contralateral to the recording site was the first to pass over the obstacle. One group (41/102) was characterized by a brief, phasic discharge as the lead forelimb passed over the obstacle (Step-related cells). These cells were recorded primarily from area 5a. The other group (61/102) showed a progressive increase in activity prior to the onset of the swing phase in the modified limb and frequently diverged from control at least one step cycle before the gait modification (Step-advanced cells). Most of these cells were recorded in area 5b. In both groups, some cells maintained a fixed relationship to the activity of the contralateral forelimb regardless of which limb was the first to pass over the obstacle (limb-specific cells), whereas others changed their phase of activity so that they were always related to activity of the first limb to pass over the obstacle, either contralateral or ipsilateral (limb-independent cells). Limb-independent cells were more common among the Step-advanced cell population. We suggest that both populations of cells contribute to the gait modification and that the discharge characteristics of the Step-advanced cells are compatible with a contribution to the planning of the gait modification.
Maternal Serum Triple Marker Levels in Immigrants to Israel from Ethiopia
Authors: Sharony Reuven , Itzhaky Deganit , Amiel Aliza , Fejgin Moshe , Cuckle Howard
Published: December 2009

Objectives: To determine if Ethiopian immigrants have similar triple marker levels as the general Israeli population. Material and Methods: Second-trimester maternal serum results on 346 Ethiopians were obtained from records of 36,309 women. Two series were constructed for comparison among patients screened between 2000 and 2001 (‘old group’) and 2005 and 2007 (‘new group’). Results: The median and 95% confidence intervals (CI) were: α-fetoprotein (AFP) 1.080 multiples of median (MoM) (95% CI 1.03–1.13); human chorionic gonadotrophin (hCG) 0.895 MoM (95% CI 0.82–0.97), and unconjugated estriol (uE3) 1.050 MoM (95% CI 1.00–1.10). The differences between the AFP and hCG medians for the old and new series were not statistically significant (p = 0.06 and 0.20) whilst the uE3 difference was significant (p = 0.04). There was a general tendency for the levels to be closer to 1 MoM over time. Conclusions: Triple marker serum levels of AFP and hCG among Ethiopian patients may need to be slightly corrected, particularly for hCG.
Peritoneal Dialysis and Hemodialysis in Systemic Lupus Erythematosus Patients: Comparison of Clinical Outcomes
Authors: Weng Cheng-Hao , Hsu Ching-Wei , Yu Chun-Chen , Yen Tzung-Hai , Yang Chih-Wei , Hung Cheng-Chieh
Published: December 2009

Background: This study compared peritoneal dialysis (PD) and hemodialysis (HD) outcomes between female systemic lupus erythematosus (SLE) patients with end-stage renal disease (ESRD) due to lupus nephropathy. Methods: 22 female SLE patients undergoing PD were compared with 14 female SLE patients receiving HD. Clinical outcomes and infective complications were reviewed. Results: The overall mortality rate was much higher in the PD group (6/22) than in the HD group (1/14) (p = 0.027). PD patients had higher C-reactive protein level (37.1 ± 41.4 vs. 6.7 ± 9.5 mg/l, p = 0.037) and numbers of infectious episode (PD vs. HD: 1 episode per 33.16 patient-months vs. 1 episode per 118.26 patient-months, respectively, p = 0.046). Before the end of the observation period, HD patients had higher serum albumin (3.8 ± 0.2 vs. 3.3 ± 0.6 g/dl, p = 0.01). Conclusions: In female SLE patients with ESRD due to lupus nephropathy, clinical outcomes are better after undergoing HD than after undergoing PD.
Endothelial Bioreactor Ameliorates Endotoxemia Sepsis in Swine
Authors: Xie Qionghong , Liu Junfeng , Gu Yong , Ping Yi , You Li , Zhong Jianyong , Li Yi , Hasegawa Hyo , Liang Weimin , Lin Shanyan , Ding Feng
Published: December 2009

Introduction: Severe sepsis involves a complex response including the activation of lots of cells, inflammatory mediators, and the hemostatic system. Central to this process is an alteration of endothelial cell function. Therefore, we investigated whether an endothelial bioreactor (EBR) would provide a new therapeutic approach to this clinical disorder. Methods: EBR was constructed using a cartridge which contained with nonwoven polytetrafluoroethylene seeded with porcine iliac artery endothelial cell (PIEC). Pigs were intravenously administered with 0.25 mg/kg lipopolysaccharide and immediately placed in an extracorporeal circuit with EBR or sham controls. Results: Compared with the sham group, EBR therapy resulted in significantly higher mean arterial blood pressure and significantly lower plasma von Willebrand factor, endothelin-1 and scores of lung injury. These alterations were associated with a significant survival advantage in the EBR group. Conclusions: Timely intervention with EC therapy in a tissue-engineered bioreactor may improve cardiovascular performance and alter the natural history of endotoxemia sepsis.
Telomeres and Immunological Diseases of Aging
Authors: Andrews Nicolas P. , Fujii Hiroshi , Goronzy Jörg J. , Weyand Cornelia M.
Published: December 2009

A defining feature of the eukaryotic genome is the presence of linear chromosomes. This arrangement, however, poses several challenges with regard to chromosomal replication and maintenance. To prevent the loss of coding sequences and to suppress gross chromosomal rearrangements, linear chromosomes are capped by repetitive nucleoprotein structures, called telomeres. Each cell division results in a progressive shortening of telomeres that, below a certain threshold, promotes genome instability, senescence, and apoptosis. Telomeric erosion, maintenance, and repair take center stage in determining cell fate. Cells of the immune system are under enormous proliferative demand, stressing telomeric intactness. Lymphocytes are capable of upregulating telomerase, an enzyme that can elongate telomeric sequences and, thus, prolong cellular lifespan. Therefore, telomere dynamics are critical in preserving immune function and have become a focus for studies of immunosenescence and autoimmunity. In this review, we describe the role of telomeric nucleoproteins in shaping telomere architecture and in suppressing DNA damage responses. We summarize new insights into the regulation of telomerase activity, hereditary disorders associated with telomere dysfunction, the role of telomere loss in immune aging, and the impact of telomere dysfunction in chronic inflammatory disease.
Introduction: Civicness, Equality, and Democracy—A “Dark Side” of Social Capital?
Authors: van Deth Jan W. , Zmerli Sonja
Published: December 2009

Debates about social capital usually focus on its presumed positive consequences. Although this expectation has been corroborated empirically, in many instances some less benign consequences of social capital have also been uncovered. Several explanations for the emergence and consequences of these “dark sides” of social capital are briefly presented here and, subsequently, put to empirical testing. The contributors to this issue of American Behavioral Scientist have a common understanding of these dark sides of social capital. Conceptualizing them as negative consequences or outcomes, the authors use various research strategies to scrutinize the nature of the effects of social capital in various situations. In each analysis, however, particular focus is placed on the importance of the contextual setting. Special attention is paid to the degree of democratization, the postcommunist legacy, different welfare state regimes, the saliency of political cleavages, and types and interconnectedness of voluntary associations. The findings suggest that the specific consequences of social capital largely depend on political and social conditions.
Participation in Voluntary Associations: Dark Shades in a Sunny World?
Authors: van Deth Jan W.
Published: December 2009

The benevolent consequences of social capital are clearly related to membership in voluntary associations. Irrespective of the type of association, members in voluntary associations in 19 European democracies show higher levels of satisfaction with democracy and higher levels of political engagement than nonmembers. “Bad” forms of social capital are not widely spread among voluntary associations, but potentially any type of association can be depicted as a “bad” form of social capital. In particular, religious organizations frequently appear as an example of “bad” social capital. Because this last conclusion is related to political saliency, only a few “dark shades” in the mainly sunny world of voluntary associations in Europe can be observed.
Social Capital and Norms of Citizenship: An Ambiguous Relationship?
Authors: Zmerli Sonja
Published: December 2009

From a theoretical viewpoint, the consequences of social capital for norms of citizenship are usually perceived as benign. However, empirical evidence indicates that its impact may be detrimental. To investigate this phenomenon further, this article examines the specific nature of the relationships among social involvement, social trust, and four different types of norms of citizenship. Social capital acts on these norms in two different ways. First, it varies with the specific norms of citizenship. Second, the different components of social capital do not necessarily exert similar effects. In this article, the negative and significant relationships between social trust and norms of social order are revealed, indicating the “dark sides” of social capital. This finding challenges the common wisdom about the positive interrelationship between social capital and a citizenry’s public spiritedness in a democratic state.
The Saliency of Political Cleavages and the “Dark Sides” of Social Capital: Evidence From Spain
Authors: García Albacete Gema M.
Published: December 2009

This article explores the effects that a salient political center—periphery cleavage has on the structure (social networks) and outcomes (political attitudes) of social capital. The comparison of different regions within the same country supports the thesis that social capital is a reflection of the context in which it takes place. In this framework, social capital undermines equal representation of citizens’ identities. Second, political fragmentation is reproduced by the existence of more bonding than bridging social capital. Finally, it allows for the identification of scenarios in which involvement in informal social networks leads to both positive and negative consequences for citizens’ attitudes toward politics.
Voluntary Associations and Tolerance: An Ambiguous Relationship
Authors: Iglič Hajdeja
Published: December 2009

In the debate on social capital, it is usually assumed that membership in voluntary associations is highly beneficial for the formation of civic values among the association’s affiliates. Despite these theoretical expectations, comparative studies have so far found only a weak statistical relationship between associational involvement and tolerance in Western democracies and a nonsignificant or even negative relationship in the case of Eastern and Central European countries. In this article, the author further investigates the negative relationship between associational involvement and attitudes of social and political tolerance, the “dark side” of social capital. The author shows that when members of voluntary associations build particularized trust rather than generalized trust, this decreases their already low levels of social tolerance. Such situations are especially common in the countries of Eastern and Central Europe. Associational involvement also has negative effects on political tolerance. Associations are social contexts within which processes of interpersonal influence and political mobilization take place. This results in the reinforcement of civic as well as uncivic orientations of associational members.
Trotsky and Development Theory in Latin America
Authors: Chilcote Ronald H.
Published: December 2009

Elaboration of four concepts in the thought of Trotsky (backwardness, combined and uneven development, permanent revolution, and socialist transition and revolution) that are useful in understanding developmental theory and their relevance to theories of capitalist development, underdevelopment, and dependency, as prominently manifested in Latin America during the last half of the 20th century. Identification of Trotskyist movements and their splinter tendencies. Examination of principal theorists and their ideas, with emphasis on Argentine and Brazilian thought and their relevance to developmental theory.
Hydrothermal Corrosion of Magnesia-Pyrochlore Composites for Inert Matrix Materials
Authors: Peng Xu  , Yates Samantha J. , Nino Juan C.
Published: December 2009

The corrosion behavior of MgO-Nd2Zr2O7 cercer composites was investigated under hydrothermal conditions at 300°C and saturation pressure. It was found that corrosion resistance was microstructure dependent in terms of MgO contiguity and homogeneity. The inhomogeneous composites completely dissolved in less than 1 h showing poor hydration resistance similar to MgO. The homogeneous composites exhibited an improved hydration resistance and the corrosion was primarily limited to the surface. The normalized mass loss (NML) was proportional to the corrosion time and the NML rate increased with MgO volume fraction. The corrosion process followed an Arrhenius relationship and the apparent activation energy was calculated to be ∼39-41 kJ/mol. It is suggested that the mass loss of the MgO-Nd2Zr2O 7 composites is mainly governed by hydration of MgO and the NML rate is enhanced by contiguity of MgO. A desirable microstructure with enhanced corrosion resistance is viewed to have minimum contiguity of MgO, good homogeneity, and large MgO grain size (minimizing grain boundaries).
Educational Reforms and Inequalities in Israel: The MMI Hypothesis Revisited
Authors: Ayalon Hanna , Shavit Yossi
Published: December 2009

Israeli secondary school students sit for national matriculation examinations that result in their receiving either a plain or a university-qualifying diploma. During the 1990s, the Ministry of Education implemented policies that were designed to raise eligibility rates for the diploma. This article evaluates the consequences of these policies for gender, ethnic, and socioeconomic inequalities in the odds of obtaining the two forms of the diploma. The results show that the reforms reduced socioeconomic inequalities in the odds of obtaining the plain diploma but increased inequalities in the odds of obtaining the university-qualifying diploma. Overall, the results refute the prediction of Raftery and Hout's (1993) hypothesis of maximally maintained inequality that inequalities are maintained as long as privileged groups have not reached saturation vis-à-vis an educational level. Rather, they are consistent with Lucas's (2001) claim that the differentiation of a given educational credential can substitute qualitative inequalities for quantitative ones.
Schools' Racial Mix, Students' Optimism, and the Black-White and Latino-White Achievement Gaps
Authors: Goldsmith Pat António
Published: December 2009

This article examines how schools' racial and ethnic mix of students and teachers influences black, white, and Latino students' occupational expectations, educational aspirations, and concrete attitudes. Findings from multilevel-model analyses of data from the National Education Longitudinal Study show that Latinos' and blacks' beliefs are more optimistic and more pro-school in segregated-minority schools, especially when these schools also employ many minority teachers. Further analyses indicate that the positive effects of segregated-minority schools on blacks' and Latinos' beliefs reduce the black-white and Latino-white gaps in achievement. These findings suggest that teachers and administrators in segregated-white schools need to address how they lower minority students' beliefs and that segregated-minority schools can be improved by hiring many minority teachers.
Beyond Decoupling: Rethinking the Relationship Between the Institutional Environment and the Classroom
Authors: Coburn Cynthia E.
Published: December 2009

The decoupling argument—that schools respond to pressures from the institutional environment by decoupling changes in structures from classroom instruction—has been a central feature of institutional theory since the early 1970s. This study suggests the need to rethink this argument. Drawing on a study of the relationship between changing ideas about reading instruction in California from 1983 to 1999 and teachers' classroom practice, the study provides evidence that messages about instruction in the environment influence classroom practice in a process that is framed by teachers' preexisting beliefs and practices and the nature of the messages themselves. Implications are drawn for theories of teachers' autonomy and methodological approaches to studying macro-micro linkages.