bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase Formation and Properties in the System Bi2O3:2CoO1+x:Nb2O5
Authors: Vanderah Terrell A. , Siegrist Theo , Lufaso Michael W. , Yeager Margaret C. , Roth Robert S. , Nino Juan C. , Yates Samantha
Published: October 2006

Subsolidus phase relations have been determined for the Bi–Co–Nb–O system in air (750–925 °C). Ternary compound formation was limited to pyrochlore (A2B2O6O′), which formed a substantial solid solution region at Bi‐deficient stoichiometries (relative to Bi2Co2/3Nb4/3O7) suggesting that about 8 to 25 % of the A sites are occupied by Co. X‐ray powder diffraction data confirmed that all Bi–Co–Nb–O pyrochlores exhibit displacive behavior. A structural refinement of the pyrochlore Bi1.56Co0.96Nb1.48O7 using single‐crystal X‐ray diffraction data is reported with the A and O′ atoms displaced (0.34 Å and 0.45 Å, respectively) from ideal positions to96g sites and 32e sites, respectively [Fd3$\bar {S}$m (#227), a = 10.551(1) Å]. The displacive structural behavior is similar to that found in analogous Bi–M–Nb–O pyrochlores (M = Zn, Fe, Mn). Bi–Co–Nb–O pyrochlores exhibited overall paramagnetic behavior with negative Curie–Weiss temperature intercepts indicating weak antiferromagnetic interactions. At 250 K and 1 MHz the relative dielectric permittivity of the pyrochlore 0.4400:0.2100:0.3500 Bi2O3:2CoO1+x:Nb2O5 was ca. 115 with tan δ = 0.06; however, at lower frequencies the sample was conductive. Low‐temperature dielectric relaxation such as that observed for Bi1.5Zn0.92Nb1.5O6.92 and other bismuth‐based pyrochlores was not observed. Consideration of bond lengths, effective magnetic moments, and dielectric properties suggests that the average oxidation state of Co in the pyrochlore phases is close to but slightly higher than 2.0. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
State‐level accountability for higher education: On the edge of a transformation
Authors: Ewell Peter T. , Jones Dennis P.
Published: October 2006

Public accountability for higher education has undergone a paradigm shift.
siRNA‐mediated type 1 insulin‐like growth factor receptor silencing induces chemosensitization of a human liver cancer cell line with mutant P53
Authors: Niu Jian , Xu Zonghua , Li Xiang‐nong , Han Zeguang
Published: October 2006

Overexpression of type 1 insulin‐like growth factor receptor (IGF1R) contributes to the progression and metastasis of liver cancer, implying that IGF1R gene is a suitable target of RNA interference (RNAi) for liver cancer therapy. To investigate the possible regulation of IGF1R by P53, we examined the level of IGF1R expression in liver cancer cell lines in response to adriamycin. Levels of IGF1R mRNA and protein in cell lines with wild‐type P53 decreased dramatically after P53 induction, but no such reduction of IGF1R was observed in cell lines with mutated P53. Inhibition of wild‐type P53 in HEPG2 cells by small interfering RNA (siRNA) significantly upregulated the expression of IGF1R. IGF1R inhibition by siRNA in Huh7 cells with mutated P53 significantly depressed cell proliferation. To investigate the sensitivity of cancer cells to adriamycin after inhibition of IGF1R, we depressed IGF1R expression using siRNA, and then added adriamycin at an IC50 dose. After a further 48 h incubation with adriamycin, proliferation was significantly depressed in the cells treated with siRNA targeting IGF1R, in comparison with siRNA targeting scramble. Furthermore, both TUNEL and pro‐caspase‐3 expression assay showed a significant increase in apoptosis after combined treatment with adriamycin and siRNA targeting IGF1R. Our results demonstrate that IGF1R is downregulated by P53, and that siRNA targeting of IGF1R increases liver cancer cells sensitivity to adriamycin and promotes apoptosis. siRNA targeting of IGF1R could be potentially useful for increasing sensitivity to anti‐cancer drugs, especially in drug‐resistant cells with mutated P53.
A change in N‐terminal pro‐brain natriuretic peptide is predictive of outcome in patients with advanced heart failure
Authors: Gardner Roy S. , Chong Kwok S. , Morton James J. , McDonagh Theresa A.
Published: October 2006

Background:

The prognosis of chronic heart failure has improved with modern medical therapy. However, identifying those patients who fail to respond to such therapy and therefore those who remain at high risk is notoriously difficult. The B‐type natriuretic peptides are established independent predictors of prognosis in CHF. However, the relevance of a change in NT‐proBNP concentration over time in advanced heart failure is unknown.

Methods:

We prospectively studied 133 patients with advanced CHF referred for consideration of cardiac transplantation. Plasma for NT‐proBNP analysis was sampled at baseline and a median of 4months later in the 112 patients surviving without cardiac transplantation. Patients were followed up for a median of 1003days.

Results:

The primary endpoint of all‐cause mortality occurred in 30 (26.8%) patients. Those subjects who had the highest NT‐proBNP concentration at 4months were at the greatest risk of death (log rank statistic=10.4, p=0.001). On Cox regression analysis, both a NT‐proBNP concentration above the median and an absolute increase in NT‐proBNP were independent predictors of mortality (χ2=53, p<0.0001 and χ2=17.3, p<0.0001, respectively).

Conclusion:

A single NT‐proBNP concentration above the median and a change in NT‐proBNP concentration over a 4‐month period were independent predictors of mortality in patients with advanced heart failure.
Simulations of Kelvin–Helmholtz modes in the dusty plasma environment of noctilucent clouds
Authors: WIECHEN HEINZ M.
Published: October 2006

We present results of quantitative multi-fluid simulations of the nonlinear dynamics of Kelvin–Helmholtz modes in the partially ionized dusty plasma of noctilucent clouds. Noctilucent clouds are a typical example of dusty plasmas in the Earth's mesosphere/lower thermosphere. A specific feature observed in noctilucent clouds is wavy, turbulent structure. Possible explanations for these structures, which are discussed in the literature, are based on hydrodynamical models. The dusty plasma aspect has been widely neglected, so far. In this paper we examine the nonlinear dynamics of Kelvin–Helmholtz modes in noctilucent clouds from the viewpoint of dusty plasma dynamics. The corresponding results are in good qualitative and quantitative agreement with observations.
Solar influence on the tropical stratosphere and troposphere in the northern summer
Authors: Kodera Kunihiko , Shibata Kiyotaka
Published: October 2006

Solar influence on the tropical stratosphere and troposphere in northern summer is studied by using reanalysis data from 1958 to 2004. Temperature tendency and vertical velocities are investigated to demonstrate an importance of the development of solar signal from June to August. The use of the temperature tendency reduced a problem due to the change of the observation system, and made possible to revealed a clear relationship between the stratospheric meridional circulation and the Indian ocean monsoon circulation in the troposphere through four solar cycles.
Mass variation in the Mediterranean Sea from GRACE and its validation by altimetry, steric and hydrologic fields
Authors: Fenoglio‐Marc L. , Kusche J. , Becker M.
Published: October 2006

The seasonal seawater mass variation in the Mediterranean Sea is estimated between April 2002 and July 2004 from GRACE and altimetry data and from hydrologic and oceanographic models. A smoothed spatial averaging kernel is applied to each field, in order to obtain comparable basin averages. The GRACE seawater mass corrected for the leakage of continental hydrology and the filtered steric‐corrected altimeter sea level have similar annual amplitude and phase. To restore the magnitude of the GRACE‐derived water mass signal we apply a scaling factor to the smoothed annual amplitude. The estimated scaled mass signal has an annual amplitude of 52 ± 17 mm peaking in November. We combine the seawater mass variation with the Mediterranean freshwater deficit and obtain a net flow at the Strait of Gibraltar with annual amplitude of 60 ± 25 mm/month (0.06 Sv) and maximum in September.
Testing statistical downscaling methods in simulated climates
Authors: Frías M. D. , Zorita E. , Fernández J. , Rodríguez‐Puebla C.
Published: October 2006

The consistency of two statistical downscaling methods and two different predictors to estimate past (last millennium) and future (21st century) precipitation in the Iberian and Scandinavian Peninsulas is assessed in the surrogate climate of a coupled climate model simulation. The methods are based on canonical correlation analysis and the search for analogs, with sea level pressure (SLP) and 500 mb geopotential height as predictors. The precipitation downscaled by the statistical methods within the simulated climate is compared with the direct model output. The estimation based on SLP alone agrees with the modeled precipitation on the Iberian Peninsula. However, the estimates for Scandinavia in the 21st century are drier than the target precipitation. Geopotential height as predictor performs worse than SLP in both regions yielding too dry future climate. Differences in both regions are analyzed in terms of relative humidity, which contributes to future precipitation changes of Scandinavian precipitation.
Current fast ion collective Thomson scattering diagnostics at TEXTOR and ASDEX Upgrade, and ITER plans (invited)
Authors: Korsholm S. B. , Bindslev H. , Meo F. , Leipold F. , Michelsen P. K. , Michelsen S. , Nielsen S. K. , Tsakadze E. L. , Woskov P. , Westerhof E. , team FOM ECRH , Oosterbeek J. W. , Hoekzema J. , Leuterer F. , Wagner D. , team ASDEX Upgrade ECRH
Published: October 2006

Fast ion physics will play an important role on ITER where confined alpha particles will affect plasma dynamics and overall confinement. Fast ion collective Thomson scattering (CTS) using gyrotrons has the potential to meet the need for measuring the spatially localized velocity distributions of confined fast ions in ITER. Currently, CTS experiments are performed at TEXTOR using a 150kW, 0.2s, 110GHz gyrotron and a receiver upgraded at the Risø National Laboratory. The gyrotron and receiver optics have also been upgraded for rapid scanning during a plasma shot. The receiver consists of a nine-mirror quasioptical transmission line including a universal polarizer and a 42-channel data acquisition system, which allows complete coverage of the double sideband scattered spectrum for localized (∼10cm) time resolved (4ms) measurements of the ion velocity distribution. At ASDEX Upgrade (AUG) a similar 50-channel CTS receiver has been installed. This CTS system will use the 105GHz frequency of a dual frequency gyrotron. The gyrotron is presently being commissioned. CTS campaigns are scheduled for the summer of 2006 with a probe power of up to 1MW for 10s. This report presents the alignment of the quasioptical transmission line, calibration, and gyrotron tuning of the TEXTOR and AUG CTS systems. We will also review the progress on the design of the proposed fast ion CTS diagnostic for ITER. It is envisaged that scattered radiation from two 60GHz probe beams launched from the low field side midplane port will be received by two arrays of receivers located on the low and high field sides of the plasma. This geometry will allow the ion velocity distribution near perpendicular and near parallel to the magnetic field to be measured in ten or more spatial locations covering the full plasma cross section. The temporal resolution can be significantly better than the required 100ms.
High performance Li6F-diamond thermal neutron detectors
Authors: Marinelli Marco , Milani E. , Prestopino G. , Scoccia M. , Tucciarone A. , Verona-Rinati G. , Angelone M. , Pillon M. , Lattanzi D.
Published: October 2006

Fabrication reproducibility and high performance reliability were obtained in fissile-material-free thermal neutron detectors based on chemical vapor deposited diamond in a multilayered p-type/intrinsic/metal design. Under α particle irradiation, all the detectors (more than ten) have shown 100% charge collection efficiency and approximately 1.5% energy resolution. A Li6F layer was deposited on the detector surface as converting material for thermal neutrons through the Li6(n,α)T nuclear reaction. Both the 2.73MeV tritium and the 2.06MeV α peaks are detected and clearly resolved. Stable performance and excellent linear behavior of the count rate versus the incident neutron flux were observed.
Thermal stability of LiTaO3 domains engineered by scanning force microscopy
Authors: Liu Xiaoyan , Kitamura Kenji , Terabe Kazuya
Published: October 2006

The stability of domains engineered in near-stoichiometric and congruent composition LiTaO3 crystals was investigated after heat treatment using scanning force microscopy. Piezoresponse images of the domains showed that the heat treatment had induced backswitching in the near-stoichiometric crystals and that the degree of backswitching depended on the domain structure and heating temperature. No backswitching was observed in the congruent composition crystals after the same heat treatment. The thermal stability of engineered LiTaO3 domains thus depends on the number of nonstoichiometric defects, the domain wall energy, and the pyroelectric effect.
Spatio-temporally-complex concentration profiles using a tunable chaotic micromixer
Authors: Hsu Chia-Hsien , Folch Albert
Published: October 2006

The ability to present cells with stimuli that vary in space and time is key for a mechanistic understanding of dynamic processes such as cell migration, growth, adaptation, and differentiation. Microfluidic gradient devices that output multiple concentrations of a given compound exist, but changing the output generally requires a change in flow rates that can be confounding in biological measurements and/or impractical for high-throughput applications. We present chaotic mixers that generate multiple, complex concentration gradients that can be smoothly varied in time without significantly altering the flow rate.
Microwave plasma-assisted premixed flame combustion
Authors: Hemawan K. W. , Romel C. L. , Zuo S. , Wichman I. S. , Grotjohn T. A. , Asmussen J.
Published: October 2006

A compact microwave plasma/combustion torch has been operated at atmospheric pressure in both plasma-only and plasma-assisted premixed combustion modes. The torch burns CH4∕O2 mixtures with plasma enhancement that modifies combustion, flame structure, flame size, and flame power density. The microwave energy also extends the fuel-lean burn limits.
Determination of Fe3+ sites in a NaFeSi2O6 glass by neutron diffraction with isotopic substitution coupled with numerical simulation
Authors: Weigel Coralie , Cormier Laurent , Galoisy Laurence , Calas Georges , Bowron Daniel , Beuneu Brigitte
Published: October 2006

Isotopic substitution in neutron diffraction combined with empirical potential structure refinement simulations has been employed to probe the sites occupied by Fe3+ and Fe2+ in a NaFeSi2O6 glass. This study reveals the presence of two populations of Fe3+ sites. 95% of Fe3+ is in tetrahedral sites (dFe3+–O=1.866±0.001Å), as the remainder ferric iron and ferrous iron (∼20% of total Fe) are five coordinated.
PER1Is Required for GPI-Phospholipase A2Activity and Involved in Lipid Remodeling of GPI-anchored Proteins
Authors: Fujita Morihisa , Umemura Mariko , Yoko-o Takehiko , Jigami Yoshifumi
Published: October 2006

Glycosylphoshatidylinositol (GPI) anchors are remodeled during their transport to the cell surface. Newly synthesized proteins are transferred to a GPI anchor, consisting of diacylglycerol with conventional C16 and C18 fatty acids, whereas the lipid moiety in mature GPI-anchored proteins is exchanged to either diacylglycerol containing a C26:0 fatty acid in the sn-2 position or ceramide in Saccharomyces cerevisiae. Here, we report on PER1, a gene encoding a protein that is required for the GPI remodeling pathway. We found that GPI-anchored proteins could not associate with the detergent-resistant membranes in per1Δ cells. In addition, the mutant cells had a defect in the lipid remodeling from normal phosphatidylinositol (PI) to a C26 fatty acid–containing PI in the GPI anchor. In vitro analysis showed that PER1 is required for the production of lyso-GPI, suggesting that Per1p possesses or regulates the GPI-phospholipase A2activity. We also found that human PERLD1 is a functional homologue of PER1. Our results demonstrate for the first time that PER1 encodes an evolutionary conserved component of the GPI anchor remodeling pathway, highlighting the close connection between the lipid remodeling of GPI and raft association of GPI-anchored proteins.
Nitrogen fixation in the stag beetle, Dorcus (Macrodorcus) rectus (Motschulsky) (Col., Lucanidae)
Authors: Kuranouchi T. , Nakamura T. , Shimamura S. , Kojima H. , Goka K. , Okabe K. , Mochizuki A.
Published: October 2006

Abstract:  Stag beetles are xylophagous insects that feed mainly on dead wood. They play an important role in the decomposition of dead wood in forest ecosystems. Most dead wood contains 1% nitrogen at most. It is suspected that stag beetles can utilize atmospheric nitrogen. We show that the larvae of Dorcus (Macrodorcus) rectus exposed to nitrogen reduce acetylene to ethylene in a time‐dependent fashion. No reaction was detected with the dead wood or autoclaved larvae, suggesting that living larvae use the reaction for fixing nitrogen. Acetylene reduction to ethylene by larvae increased with incubation time. This effect was not seen using decayed wood only, autoclaved wood only or autoclaved larvae. Acetylene reduction by the larva proceeded at 1.25 ± 0.37 nmol acetylene/h/g (fresh wt), corresponding to the fixation of 0.25 μg nitrogen per day per larva.
THE DISTRIBUTION OF TRYPTOPHAN HYDROXYLASE IN CAT BRAIN
Authors: Peters D. A. V. , McGeer P. L. , McGeer E. G.
Published: October 2006

Abstract— The distribution of tryptophan hydroxylase in the cat brain was investigated and found to parallel roughly the distribution of serotonin. The most active areas are the caudate nucleus, septal area, anterior perforating substance, hypothalamus, amygdala and various areas of the midbrain.
CHOLINESTERASE ACTIVITY OF THE MOTOR ENDPLATE IN ISOLATED MUSCLE MEMBRANE
Authors: Namba T. , Grob D.
Published: October 2006

Abstract— The cholinesterase activity of motor endplates in tibialis anterior muscle of rats accounted for about 20 per cent of the total cholinesterase activity of the muscle. In the isolated muscle membrane preparation of rat intercostal muscle, the cholinesterase activity was localized solely in the motor endplate, as shown by cholinesterase staining. The cholinesterase activity of the membrane per unit of nitrogen was 26·9 times that of the muscle homogenate. The membrane (endplate) cholinesterase had an optimal pH of 8, Km value of 3·1 mm, and was stable at 4° for at least 13 days. Cholinesterase of a motor endplate hydrolysed 2·69 × 108 acetylcholine molecules in 1 msec. Since it is estimated that 108 cholinesterase active sites are present in a motor endplate, the turnover time (time necessary for one enzyme site to hydrolyse one acetylcholine molecule) is calculated to be 372 μsec, and the turnover number (molecules of acetylcholine hydrolysed by one enzyme site/min) to be 1·61 × 105. From studies with cholinesterase inhibitors, cholinesterase activity was estimated to be due mostly to acetylcholinesterase, and only a minor part to pseudocholinesterase. The muscle membrane preparation seems to be useful for the study of other properties of the motor endplate.
THE ADENOSINE DIPHOSPHATE‐ADENOSINE TRIPHOSPHATE EXCHANGE REACTION OF EXTRACTED CEREBRAL MICROSOMES
Authors: SWANSON P. D.
Published: October 2006

—Microsomal fractions prepared from guinea pig cerebral cortex manifested ADP‐ATP exchange activity, 40–99 per cent of which was extractable by dilute salt solutions. All of the (Na+, K+)‐ATPase activity remained in the particulate material. The unextracted ADP‐ATP exchange activity was stimulated six to seven fold by a non‐ionic detergent (Lubrol W). When pre‐extracted microsomes were sedimented in a sucrose density gradient, the ADP‐ATP exchange activity was more widely distributed than (Na+, K+)‐ATPase or adenylate kinase activities. The ADP‐ATP exchange activity of microsomes extracted with NaI was stimulated by Na+ ions when the Mg2+ concentration in the reaction mixture was low (0·2 mm). The Na+ stimulation of exchange activity was more variable than was the stimulation of phosphate formation by Na+ plus K+. The Na+‐stimulated ADP‐ATP exchange reaction of extracted microsomes may be a component of the (Na+, K+)‐ATPase system, which has not been freed from adenylate kinase or possibly other contributing enzyme systems.
NON‐ENZYMIC INCORPORATION OF AMINES INTO PROTEOLIPID PROTEIN1
Authors: Mokrasch L. C. , Andelman R.
Published: October 2006

—Proteolipid protein binds biogenic amines irreversibly. The bound amines can be recovered as the original compounds and as complexes with polypeptide after proteolysis or acid hydrolysis. The properties of the protein‐bound tryptamine are consistent with the concept that the amine is covalently linked by its primary amine group. Mescaline, 3,4‐dihydroxyphenylethylamine, 5‐hydroxytryptamine (5‐HT) and histamine also bind irreversibly to proteolipid protein. 5‐Hydroxytryptamine and mescaline bind similarly to other proteins (casein, ovalbumin, serum albumin and a serum protein mixture), but proteolipid binds the amines to a greater extent.
THE METABOLISM OF γ‐AMINOBUTYRIC ACID (GABA) IN THE LOBSTER NERVOUS SYSTEM–UPTAKE OF GABA IN NERVE‐MUSCLE PREPARATIONS1
Authors: Iversen L. L. , Kravitz E. A.
Published: October 2006

Abstract—

The lack of information on the mechanism of inactivation of the crustacean neuromuscular inhibitory transmitter compound prompted a study of the disposition of radioactive γ‐aminobutyric acid (GABA) in lobster nerve‐muscle preparations.

A specific GABA transport system was found. Radioactive GABA was concentrated by the tissues to levels several times those in the medium, and net uptake could be demonstrated. The process was dependent on sodium ions in the medium; neither lithium nor choline could substitute for sodium. Incubations with increasing GABA concentrations indicated that uptake was a saturable mechanism with an apparent Km of 5.8 × 10−5m.

Of many compounds tested, only desmethylimipramine, chlopromazine (and several related compounds), and certain close structural analogues (guanidinoacetic acid, β‐guani‐dinopropionic acid and,β‐hydroxy‐GAB A) were effective inhibitors of uptake. The inhibition with all these compounds, however, was at high concentrations (5 × 10−4 to 10−3m) which limited their usefulness for physiological studies.

A separate uptake mechanism for glutamate was found in the lobster nerve‐muscle preparations. This process was not described in detail, but certain properties are similar to those of the GABA transport system.

The cellular location of the GABA uptake system remains unknown. By analogy with noradrenaline inactivation, however, it is postulated that uptake could serve to terminate the physiological actions of GABA by rapidly removing it from its sites of action in synaptic clefts.
FLOW OF PROTEIN AND RIBONUCLEIC ACID IN PERIPHERAL NERVE
Authors: Bray J. J. , Austin L.
Published: October 2006

Abstract— –Radioactively labelled leucine and orotic acid were injected into the ventral horn of the lumbar region of the spinal cord. The outflow of labelled products into the sciatic nerve was studied.

Leucine is rapidly incorporated into protein and to a lesser extent into lipid. The labelled protein is transported down the nerve, apparently by axoplasmic flow. This labelled protein was present in all sub‐cellular fractions of nerve although the soluble fraction had the highest specific activity.

Orotic acid is converted to a number of nucleotide derivatives and RNA. Both the nucleotides and RNA move down the sciatic nerve, but the pattern of movement is diffuse whereas protein appears to move as a discrete band.

The results suggest that two systems may be operating, one in which part of the RNA is transported by axoplasmic flow along the nerve and the other involving a synthesis of RNA in the nerve from precursors which flow down the nerve. This labelled RNA was membrane bound and on sedimentation analysis, proved to be predominantly of ribosomal type.
PHOSPHOLIPIDS IN THE NERVOUS SYSTEM OF MOLLUSCS
Authors: Kreps E. , Smirnov A. , Chirkovskaya E. , Patrikeeva M. , Krasilnikova V.
Published: October 2006

Abstract The phospholipid composition of nervous ganglia of the bivalve Unio crassa, the gastropod Helix pomatia and the cephalopods Octopus sp. and Ommastrephes sloanei pacificus have been investigated.

The ganglia of cephalopods contain considerably more phospholipids than do gastropod and bivalve ganglia. Especially rich in phospholipids are the optic ganglion of the squid Ommastrephes and the cerebral ganglion of Octopus, where their content is of the same order as in the brain of teleosts and amphibia.

In the ganglia of the lower molluscs, the bivalve and the gastropod, no sphingomyelin nor X‐phospholipid could be detected.

No sphingomyelin nor X‐phospholipid were found in the optic ganglion of Octopus, whereas in its cerebral ganglion sphingomyelin but no X‐phospholipid was present.

In both the optic and the cerebral ganglia of the squid Ommastrephes both sphingomyelin and X‐phospholipid were found.
SELECTIVE INCREASE OF BRAIN DOPAMINE INDUCED BY γ‐HYDROXYBUTYRATE: STUDY OF THE MECHANISM OF ACTION*
Authors: Gessa G. L. , Crabai F. , Vargiu L. , Spano P. F.
Published: October 2006

Abstract— γ‐Hydroxybutyrate (γ‐OH) produces a selective accumulation of brain DA not only in normal animals but also in reserpinized animals. This is especially evident after the administration of DOPA; while in parallel experiments γ‐OH does not influence significantly the amount of 5‐HT present in brain after 5‐HTP treatment.

γ‐OH does not raise DA in rats after inhibition of tyrosine hydroxylase. The accumulation of brain DA is not due to inhibition of MAO or COMT activity.
THE HETEROGENEITY OF RAT BRAIN MITOCHONDRIA ISOLATED ON CONTINUOUS SUCROSE GRADIENTS1
Authors: Neidle A. , Van Den Berg C. J. , Grynbaum A.
Published: October 2006

Abstract— The distribution of a series of enzymes in the post‐nuclear supernatant of rat brain homogenates was investigated following continuous density‐gradient centrifugation. The enzymes studied were acetyl coenzyme A synthetase, glutamic dehydrogenase, glutamine synthetase, glutaminase I, succinic dehydrogenase and monoamine oxidase. Each of these enzymes with the exception of glutamine synthetase appears predominantly in the mitochondrial region of the gradient. Although about 20 per cent of this enzyme is present in the crude mitochondrial pellet, on density gradient centrifugation no special association of glutamine synthetase with any of the mitochondrial fractions was observed. Each of the other enzymes studied was found to have a characteristic distribution in the gradient; this suggests that brain mitochondria may be heterogeneous both in buoyant density and in their enzyme content. Three principal fractions are described: (i) dense particles containing high concentrations of acetyl coenzyme A synthetase and glutamic dehydrogenase; (ii) a fraction comprising the bulk of the mitochondria with high levels of monoamine oxidase, succinic dehydrogenase and glutaminase I; and (iii) particles in the synaptic ending region of the gradient characterized by relatively high levels of monoamine oxidase and succinic dehydrogenase and containing only small amounts of the other enzymes studied.

If the mitochondrial heterogeneity that is observed on centrifugation reflects the existence within brain cells of mitochondria with specialized function, a partial explanation may be available for multiple pools of tricarboxylic acid cycle intermediates which have been postulated from isotopie labelling experiments.
IS THERE BIDIRECTIONAL TRANSPORT OF NORADRENALINE IN SYMPATHETIC NERVES?
Authors: Geffen L. B. , Hunter C. , Rush R. A.
Published: October 2006

Abstract—

The experiments were designed to detect somatopetal transport of [14C]noradrenaline in the postganglionic sympathetic nerves supplying the cat spleen and sheep eye. The animals were treated with nialamide to protect the radioactive noradrenaline, after uptake into the nerve terminals, from monoamine oxidase.

In the spleen, the transmitter stores were labelled by infusion of [14C]noradrenaline into a branch of the splenic artery. The branches of the nerves to the infused and non‐infused sides of the spleen were ligated in an attempt to arrest, distal to the constriction, any noradrenaline transported somatopetally in the axons from their terminals. After 24 hr, however, there was less radioactivity in the nerves distal compared to proximal to the constriction, despite heavier labelling of the terminal transmitter stores in the infused portion of the spleen. The proximal accumulation of radioactivity could be attributed to a somatofugal transport of [14C]noradrenaline.

Experiments were also done on the intact sympathetic nerve supply of the sheep eye. The sympathetic nerve terminals in the smooth muscle of the left eye were heavily labelled 5 days after the injection of [14C]noradrenaline into the left vitreous humour. However, both superior cervical ganglia were only lightly labelled, and there was no significant difference in the radioactivity present in the two ganglia.

The results provide no support for a bidirectional transport of noradrenaline in sympathetic nerves but are consistent with a somatofugal transport of the amine storage vesicles from their site of synthesis in the soma to the axon terminals.
DECARBOXYLATION STUDIES OF GLUTAMATE, GLUTAMINE, AND ASPARTATE FROM BRAIN LABELLED WITH [1‐14C] ACETATE, l‐[U‐14C]‐ASPARTATE, AND l‐[U‐14C]GLUTAMATE
Authors: Nicklas W. J. , Clarke D. D. , Berl S.
Published: October 2006

Abstract—

Studies in vivo and in vitro of the distribution of label in C‐1 of glutamate and glutamine and C‐4 of aspartate in the free amino acids of brain were carried out. [1‐14C]‐Acetate was used both in vivo and in vitro and l‐[U‐14C]aspartate and l‐[U‐14C]glutamate were used in vitro.

The results obtained with labelled acetate and aspartate suggest that CO2 and a 3‐carbon acid may exchange at different rates on a COa‐fixing enzyme.

The apparent cycling times of both glutamate and glutamine show fast components measured in minutes and slow components measured in hours.

With [1‐14C]acetate in vitro glutamine is more rapidly labelled in C‐1 than is glutamate at early time points; the curves cross over at about 7 min.

The results support and extend the concept of metabolic compartmentation of amino acid metabolism in brain.
TRANSGLUTAMINASE LEVELS IN BRAIN AND RETICULOENDOTHELIAL CELLS DURING ALLERGIC ENCEPHALOMYELITIS DETERMINED BY A RADIOCHEMICAL METHOD1,2
Authors: Wajda I. J. , Lee J. M. , Neidle A.
Published: October 2006

Abstract—

A sensitive method for the assay of transglutaminase based on incorporation of [14C]methylamine into carbobenzoxy l‐glutaminyl l‐valine methyl ester is described.

Transglutaminase levels were measured in the livers, brains and white cells obtained from peritoneal exudates of two strains of mice during the development of experimental allergic encephalomyelitis (EAE). The sensitive (BSVS) strain developed the disease, while the resistant (BRVR) mice did not succumb to EAE. The liver enzyme in the sensitive mice increased to significantly higher levels during the early stages of the disease. Low values were recorded in the same animals during paralysis.

Brain transglutaminase increased to 300 per cent of normal values in the sensitive mice during paralytic stages of EAE. In the resistant strain of mice transglutaminase levels doubled in the mixture of cells obtained from the peritoneal wash. In the sensitive mice, normal values were recorded in those cells.

It is suggested that transglutaminase is actively involved in immunological reactions taking place in the brain in EAE sensitive mice and in the reticuloendothelial system of EAE resistant mice.
NORADRENALINE UPTAKE INTO CEREBAL CORTEX: A HISTOCHEMICAL STUDY
Authors: Arbuthnott G. W.
Published: October 2006

Abstract— Experiments are reported which illustrate, by means of the histochemical technique of Falck and Hillarp, the distribution of noradrenaline in the cerebral cortex of the rat after topical application to small areas of the pia mater. The noradrenaline is accumulated in a system of fibres and cells in the cortex by a mechanism which can be blocked by desmethylimipramine, amphetamine and phenoxybenzamine, but not by reserpine. In sections from untreated cerebral cortex the fibres contain enough noradrenaline to be visible after histochemical preparation but the cells do not. However, due to the high concentrations of noradrenaline used, the specificity of the uptake into cell bodies must remain in doubt.
CHOLINE ACETYLTRANSFERASE ACTIVITY OF HUMAN BRAIN TISSUE DURING DEVELOPMENT AND AT MATURITY
Authors: Bull G , Hebb Catherine , Ratković Dobrila
Published: October 2006

Abstract— (1) On analysis of human brain tissue to determine its choline acetyltransferase (ChAc) content the recovery of enzyme from many regions is very poor when the tissue is acetone‐dried and then extracted in the standard manner; for this reason the method is unsuitable when quantitative recoveries are required; it is preferable to prepare sucrose homogenates and activate these with ether before incubation.

(2) From measurements made on homogenates of one adult brain the highest concentration of ChAc was found in the putamen and the lowest in the corpus callosum. The caudate nucleus also had a high activity. As in other mammals, the concentration of enzyme in the cerebellum was found to be low. Analogous results were obtained on a nine‐year‐old brain but the level of ChAc activity was generally higher than in the older brain.

(3) During foetal development up to thirty‐two weeks, ChAc is higher in the cerebellum than in the caudate, the thalamus, corpora quadrigemina, medulla and spinal cord. In all regions the concentration and total amount of enzyme rise fairly steadily up to this time; between 24 and 32 weeks, however, its concentration in the cerebellum and corpora quadrigemina falls slightly although the total increases considerably.

(4) Comparison of the results with the data of other authors indicates general agreement between the distribution of the enzyme in the human brain and its distribution in other mammals, especially the rhesus monkey. The corpus callosum may be an exception since in man it contains little ChAc while in lower mammals it seems to have relatively high concentrations of both ACh and ChAc.

(5) In comparing the values for ChAc reported here with the values for AChE reported by others, three tissues, the globus pallidus, substantia nigra and cerebellum are found to be exceptional in that relative to their concentration in the caudate the activity of ChAc is only about one‐tenth that of AChE.
PURIFICATION AND SOME PROPERTIES OF ACID MUCOPOLYSACCHARIDES OF BOVINE BRAIN
Authors: Saigo K , Egami F
Published: October 2006

Abstract— (1) Acid mucopolysaccharide was obtained from bovine brain and fractionated by Dowex 1 ×−2 column chromatography. Infrared spectra, elution profiles and chemical composition revealed that it was essentially composed of hyaluronic acid and chondroitin sulphates.

(2) Six unsaturated dissacharides containing different types of ester‐sulphate, namely ΔDi‐OSh, ΔDi‐OS, ΔDi‐4S, ΔDi‐6S, ΔDi‐diSD, and ΔDi‐diSE, were detected in the chondroitinase‐ABC and ‐AC digests of sulphated acid mucopolysaccharide fractions. Their molar fraction was determined and the monosulphated disaccharides, ΔDi‐4S and ΔDi‐6S, wére found to be the two main components. A time course curve of digestion with condroitinase‐ABC indicated the existence of small amounts of uronic acid‐containing components resistant to chondroitinase‐ABC.

(3) The peptide chains bound to acid mucopolysaccharides were mainly composed of hydrophilic amino acids. Beta‐elimination reaction was performed and at least two amino acids, serine and threonine residues, appeared to be the amino acids of the carbohydrate‐protein linkage regions of chondroitin sulphate fractions.

(4) Optical rotatory dispersion of acid mucopolysaccharide‐methylene blue complexes suggested that chondroitin sulphate of bovine brain as well as authentic chondroitin sulphate A and C belonged to right‐screw sense helical acid mucopolysaccharides, while heparin belonged to left‐screw sense.
Composition of acyl groups in the neutral glycerides from mouse brain
Authors: Sun Grace Y.
Published: October 2006

The neutral glycerides of brain are quite active metabolically, the diacylglycerols being intermediates in the biosynthesis of phosphatidyl choline and phosphatidyl ethanolamine (Rowe. 1969; Sun and Horrocks, 1969a, and unpublished data). Only trace amounts of the neutral glycerides are normally present in the brain but they can become elevated in pathological conditions (Smith and Whtte, 1968). Except for the triglycerides of rat brain (Rowe, 1969), the neutral glycerides of brain have not been characterized because of the complications in their separation from the large amounts of sterols. This communication reports the composition of acyl groups of the mono‐, di‐ and triglycerides of mouse brain.
RAPIDLY‐LABELLED, ACIDIC PHOSPHOLIPIDS OF THE GOLDFISH BRAIN1
Authors: Hollander J. , Hallenbeck J. M. , Agranoff B. W.
Published: October 2006

Abstract—

Homogenates and particulate fractions of goldfish brain incorporated radioactivity from γ‐[32P]ATP selectively into acidic phospholipids during brief periods of incubation. Phosphatidate and lysophosphatidate became strongly labelled and activity was also found in phosphatidyl inositol phosphate and in phosphatidyl inositol diphosphate. When tetraphenylborate (a K+‐complexing agent) was added, a selective stimulation of incorporation of 32P into phosphatidate occurred. The addition of perchlorate (also known to bind K+) did not produce a similar stimulation, nor did the addition of K+ block the stimulation by tetraphenylborate. The stimulation of the labelling of phospholipids by tetraphenylborate appeared to be the result of multiple actions. Besides the evidence that it acted by stimulating the phosphoinositide phosphodiesterase of brain, data were obtained suggesting that it stimulated diglyceride kinase and blocked endogenous destruction of ATP as well. The stimulation by tetraphenylborate was blocked by addition of atropine but not of arecoline.
INHIBITION OF BACTERIAL AND MAMMALIAN CHOLINE ACETYLTRANSFERASES BY STYRYLPYRIDINE ANALOGUES
Authors: White H. L. , Cavallito C. J.
Published: October 2006

—Choline acetyltransferase was extracted from Lactobacillus plantarum by relatively gentle procedures involving penicillin treatment, osmotic shock and passage through a French pressure cell. After partial purification, the extract was compared with choline acetyltransferase of calf caudate nucleus for kinetic properties and response to a class of inhibitors which consists of analogues of styrylpyridine. Both enzymes obeyed a sequential mechanism with Michaelis constants for the bacterial enzyme, Km= 8 μm vs. acetyl‐CoA and 0·44 mm vs. choline; and for the caudate nucleus enzyme, Km= 15 μm vs. acetyl‐CoA and 0·8 mm vs. choline. Both were stabilized by dithiothreitol and EDTA.

The extracts differed in that the bacterial enzyme was more labile and apparently was susceptible to conformational changes, which modified its response to the styrylpyridinetype inhibitors. The use of intact cells of Lactobacillus plantarum as an in vivo system for studying the inhibition of choline acetyltransferase by styrylpyridines was possible only for non‐quaternary analogues, which exist as an equilibrium mixture of charged and uncharged species.
THIAMINE PYROPHOSPHATASE ACTIVITY IN A FRACTION RICH IN GOLGI‐LIKE STRUCTURES FROM CRUSHED SCIATIC NERVE OF THE CAT1
Authors: De Iraldi Amanda Pellegrino , Rodríguez Georgina , Arnaiz De Lores
Published: October 2006

—The activity of thiamine pyrophosphatase was determined in segments and segment subfractions from normal and crushed sciatic nerves of the cat. Activity of the enzyme was increased in segments near the site of compression. The highest activity of the enzyme was in a fraction rich in tubular and vesicular elements resembling those observed in intact compressed nerves. On morphological grounds these structures have been interpreted as originating from Golgi‐like structures.
INHIBITION OF GLYCERALDEHYDE‐3‐PHOSPHATE DEHYDROGENASE IN MAMMALIAN NERVE BY IODOACETIC ACID
Authors: Sabri M. I. , Ochs S.
Published: October 2006

Abstract— Cat sciatic nerves were exposed to iodoacetate for a period of 5–10 min and after washing out the iodoacetate, the enzymes, glyceraldehyde‐3‐phosphate dehydrogenase (d‐glyceraldehyde‐3‐phosphate: NAD oxidoreductase (phosphorylating); EC 1.2.1.12) and lactate dehydrogenase (l‐lactate: NAD oxidoreductase; EC 1.1.1.27) were extracted from the high‐speed supernatant fraction of nerve homogenates. Concentrations of iodoacetate as low as 2.5 mm could completely block activity of glyceraldehyde‐3‐phosphate dehydrogenase but had no effect on lactate dehydrogenase. These findings are in accord with the classical concept shown earlier for muscle that iodoacetate blocks glycolysis by its action on glyceraldehyde‐3‐phosphate dehydrogenase. A complete block of activity of the enzyme was found after treatment with 2 to 5 mm‐iodoacetate for a period of 10 min and such blocks were irreversible for at least 3 h. Glyceraldehyde‐3‐phosphate dehydrogenase activity was NAD specific, with NADP unable to substitute for NAD. The results are discussed in relation to the effect of iodoacetate in blocking glycolysis and in turn the fast axoplasmic transport of materials in mammalian nerve.
METABOLIC CHARACTERISTICS OF MITOCHONDRIA ISOLATED FROM RABBIT BRAIN1
Authors: Von Korff R. W. , Steinman Sondra , Welch Annemarie S.
Published: October 2006

Abstract— Data on the metabolic characteristics of mitochondria from rabbit brain have been obtained using low concentrations (100–300 μm) of 14C‐labelled substrates of the Krebs tricarboxylic acid cycle. Oxygen consumption was measured polarographically with a Clark‐type electrode. Products of the reactions were separated by chromatography on Dowex‐1 columns. Data are reported for relative respiratory quotients of various substrates, respiratory control ratios, accumulation of 14C in various tricarboxylic acid cycle intermediates and the effect of malate and several inhibitors on these parameters. The data have been compared with similar experiments on mitochondria from rabbit heart.

Mitochondria from rabbit brain differ substantially from heart mitochondria: those from brain have a very low capacity for oxidation of acetate and other short chain fatty acids; they do not form j3‐hydroxybutyrate; they produce substantial amounts of α‐ketoglutarate and require added dicarboxylic acid to yield a maximum respiratory quotient. Like those from heart, brain mitochondria have a high capacity for pyruvate oxidation and a low Km for this substrate. The results have been discussed and compared with work reported by other investigators.
DEPENDENCE OF FAST AXOPLASMIC TRANSPORT IN NERVE ON OXIDATIVE METABOLISM
Authors: Ochs S. , Hollingsworth D.
Published: October 2006

—A crest of labelled activity moving down the sciatic nerve at 401 ± 35 mm/day after injection of the L7 dorsal root ganglion of the cat with L‐[3H]leucine characterizes fast axoplasmic transport of materials and has been studied with regard to its dependence on oxidative metabolism. Transport of labelled materials in vitro occurred if the nerve was supplied with O2 or 95 % O2+ 5 % CO2. Transport was not dependent upon continuity of the fibres with the ganglionic soma. Asphyxiation (N2) rapidly blocked fast transport in vitro. Likewise NaCN or dinitrophenol in an O2 atmosphere both effectively block fast transport within 15 min. Tetrodotoxin and procaine, agents which block excitation of the membrane, had no effect on fast transport. The inference is that oxidative metabolism supplies the energy required by the molecular mechanism underlying fast axoplasmic transport.
POST MORTEM CHANGES IN EXTRACTABLE PROTEIN AND IN TISSUE pH IN THE GUINEA PIG BRAIN
Authors: Cain D. F. , Kappy M. S.
Published: October 2006

—Guinea pigs were killed by asphyxiation with nitrogen and the soluble proteins were extracted from the brain at various times post mortem. The quantity of extractable brain protein decreased by 21 per cent when the animals remained at room temperature for 2 h post mortem. This decrease was not a consequence of extensive proteolysis or variations in blood volume but was probably a result of precipitation. After death, the pH of the brain fell rapidly to a minimum of ∼6CE4 within about 35 min. Examination of the patterns of brain proteins after acrylamide gel electrophoresis showed a concomitant decrease in the content of several protein bands.
ARYLSULPHATASES IN HUMAN BRAIN: SEPARATION, PURIFICATION, AND CERTAIN PROPERTIES OF THE TWO SOLUBLE ARYLSULPHATASES1
Authors: Harinath B. C , Robins E
Published: October 2006

Abstract— Arylsulphatases (aryl‐sulphate sulphohydrolases; E.C. 3.1.6.1) in the soluble subcellular fraction (105000g, 2 h) of human brain were partially purified by ammonium sulphate fractionation, ion exchange chromatography, and Sephadex gel filtration. Potassium‐4‐methylumbelliferone‐sulphatase (MUS‐sulphatase) adsorbed on DEAE‐cellulose was purified approximately 700‐fold over activity in the soluble fraction and the unadsorbed MUS‐sulphatase was similarly purified approximately 600‐fold. The arylsulphatase adsorbed to DEAE‐cellulose exhibited a Km value for MUS of 12.5 mM and a pH optimum of 5.7, whereas the unadsorbed arylsulphatase exhibited a Km value for MUS of 8.3 mM and a pH optimum of 5.4. The molecular weights of the two enzymes were approximately 109,600 and 51,300, respectively. Sulphate (0.5 mM) showed pronounced mixed inhibition only of the unadsorbed arylsulphatase. Ag+ ions (0.25 mM) showed 96 per cent inhibition of the adsorbed arylsulphatase, whereas an activation of the unadsorbed arylsulphatase was observed.
CHANGES OCCURRING IN THE CHEMICAL COMPOSITION OF THE CENTRAL NERVOUS SYSTEM DURING FOETAL AND POST‐NATAL DEVELOPMENT OF THE SHEEP
Authors: Patterson D. S. P. , Sweasey D. , Hebert C. Nancy
Published: October 2006

(1) The chemical composition of the CNS (separated into cerebrum, cerebellum, brain stem and spinal cord) was determined in sheep during foetal and post‐natal development and in adults.

(2) The spinal cord differed from the remainder of the CNS in growing more after the period studied (50‐day‐old foetuses to 5‐week‐old lambs) than before it. This was largely attributable to lipid accumulation.

(3) Chemical growth (accumulation of DNA, protein and lipid) proceeded linearly in spinal cord, logarithmically in cerebrum and cerebellum while in brain stem growth was described by a sigmoid function.

(4) Fat‐free dry matter, protein, total lipid, cholesterol and phospholipid concentrations increased progressively in all parts of the CNS but DNA concentrations changed little. In the cerebrum alone there was an increase in DNA concentration during maturation suggesting an increased cell population. Cholesterol was present predominantly in the free form but esters were detected in foetal tissues from 70 up to 120 days gestation.

(5) Cerebroside, the characteristic lipid of myelin, increased in concentration soon after 85 days of gestation, up to which point very low values were recorded, the rate varying according to the region of the CNS examined. Rates of increase in total regional cerebroside content were used to identify periods of myelination and the results suggest that there are two periods of peak activity, one about 20 days before birth and the other at 10‐20 days after birth.

(6) The composition of lipids added during the two phases of myelination and during maturation were characteristically different. In the spinal cord, lipid analyses best reflect changes in myelin composition.