bluuebunny/crossref_metadata_2025 huggingface dataset:
INCOMPLETE MARKETS IN INFINITE HORIZON: DEBT CONSTRAINTS VERSUS NODE PRICES1
Authors: Florenzano Monique , Gourdel Pascal
Published: December 2006

The general equilibrium model with incomplete markets is here extended to infinite horizon economies populated by a finite number of infinitely lived agents. the crucial issue that divides the infinite horizon setting from the finite horizon setting is in the nature of borrowing constraints, which added to spot constraints, define a plausible budget set for individual agents. the paper relates seven alternative definitions of equilibrium and states corresponding equilibrium existence theorems when assets are one‐period and purely financial.
MARTINGALE APPROACH TO PRICING PERPETUAL AMERICAN OPTIONS ON TWO STOCKS
Authors: Gerber Hans U. , Shiu Hlias S. W.
Published: December 2006

We study the pricing of American options on two stocks without expiration date and with payoff functions which are positively homogeneous with respect to the two stock prices. Examples of such options are the perpetuai Margrabe option, whose payoff is the amount by which one stock outperforms the other, and the perpetual maximum option, whose payoff is the maximum of the two stock prices Our approach to pricing such options is to take advantage of their stationary nature and apply the optional sampling theorem to two martingales constructed with respect to the risk‐neutral measure the optimal exercise boundaries, which do not vary with respect to the time variable, are determined by the smooth pasting or high contact condition the martingale approach avoids the use of differential equations.
PRICING AND HEDGING DOUBLE‐BARRIER OPTIONS: A PROBABILISTIC APPROACH
Authors: Geman Hélyette , Yor Marc
Published: December 2006

Barrier options have become increasingly popular over the last few years. Less expensive than standard options, they may provide the appropriate hedge in a number of risk management strategies. In the case of a single‐barrier option, the valuation problem is not very difficult (see Merton 1973 and Goldman, Sosin, and Gatto 1979). the situation where the option gets knocked out when the underlying instrument hits either of two well‐defined boundaries is less straightforward. Kunitomo and Ikeda (1992) provide a pricing formula expressed as the sum of an infinite series whose convergence is studied through numerical procedures and suggested to be rapid. We follow a methodology which proved quite successful in the case of Asian options (see Geman and Yor 1992,1993) and which has its roots in some fundamental properties of Brownian motion. This methodology permits the derivation of a simple expression of the Laplace transform of the double‐barrir price with respect to its maturity date. the inversion of the Laplace transform using techniques developed by Geman and Eydeland (1995), is then fairly easy to perform.
TAXING LAND VALUE IS JUST ANOTHER QUESTIONABLE TAX
Authors: Hartwich Oliver Marc
Published: December 2006

There has recently been much public debate about the introduction of a land value tax. To its supporters such a tax promises to achieve several goals simultaneously. On closer inspection, however, the arguments in favour of land value taxation are not convincing. On the contrary, the economic foundations on which proponents of this tax rely are dubious, and there are significant legal, moral and practical problems with land value taxation.
Freight Integration in Liner Shipping: A Strategy Serving Global Production Networks
Authors: NOTTEBOOM THEO , MERCKX FILIP
Published: December 2006

ABSTRACT  Container shipping lines are well aware of the growing importance of global production networks. While continuing to focus on improving the fundamentals, many shipping lines have developed a keen interest in other segments of the logistics and transportation market to offer integrated and worldwide services to global production networks. This paper aims to assess the overall level of freight integration in thirty‐four shipping lines, and provides an insight into the extent to which freight integration serves as a business model in liner shipping. The results point to a great variety and range of freight integration in the shipping business. Each carrier leverages its service portfolio to develop specific capabilities. There is clearly no single best strategy for the whole liner shipping industry to serve global production networks.
The Political Stability and Growth Pact is Dead: Long Live the Economic Stability and Growth Pact*
Authors: LEBLOND PATRICK
Published: December 2006

Euro area countries suspended the excessive deficit procedure (EDP) of the Stability and Growth Pact in November 2003. Surprisingly perhaps, long‐term European government bond‐holders did not react: yields barely moved. Owing to its political nature, the EDP does not matter for investors. What matters is the implicit economic pact that investors have made with Member State governments.
Insights into the gyrification of developing ferret brain by magnetic resonance imaging
Authors: Neal Jason , Takahashi Masaya , Silva Matthew , Tiao Grace , Walsh Christopher A. , Sheen Volney L.
Published: December 2006

The developmental mechanisms underlying the formation of human cortical convolutions (gyri and sulci) remain largely unknown. Genetic causes of lissencephaly (literally ‘smooth brain’) would imply that disorders in neuronal migration cause the loss of cortical convolutions. However, prior studies have suggested that loss of sulci and gyri can also arise from impaired proliferation, disrupted lamination and loss of intracortical connections. To gain further insight into the mechanisms underlying the formation of cortical convolutions, we examined the progressive brain development of the gyrencephalic ferret. In this study, we used magnetic resonance imaging to follow the temporal and spatial pattern of neuronal migration, proliferation and differentiation in relation to the onset and development of cortical convolutions. In this manner, we demonstrate that the onset of gyrification begins largely after completion of neuronal proliferation and migration. Gyrification occurs in a lateral to medial gradient, during the period of most rapid cerebral cortical growth. Cortical folding is also largely complete prior to myelination of the underlying cortical axons. These observations are consistent with gyrification arising secondary to cortical processes involving neuronal differentiation.
Isolation of functional chloroplasts from the sacoglossan mollusc Elysia viridis Montague
Authors: WILLIAMS MICHAEL L. , COBB A. H.
Published: December 2006

A novel technique has been developed in which functional chloroplasts have been isolated and purified from the symbiotic sacoglossan mollusc Elysia viridis, Montague. This entailed the progressive filtration and gel‐filtration of a hyaluronidase‐incubated homogenate. Isopycnic centrifugation of the resultant crude chloroplast suspension reduced the cytoplasmic/mitochondrial and microbody contamination by approx. 70 and 90% respectively. Purified chloroplast suspensions were capable of linear rates of 14CO2 fixation for at least 25 min at 50 μmol m2 s−1 (PPFD), even though approx. 54% of assimilate was being released into the bathing medium. Values for CO2 fixation and assimilate release were similar to those obtained for the intact mollusc.
Restriction mapping of genomic DNA from five cyanophages infecting the heterocystous cyanobacteria Nostoc and Anabaena
Authors: BANCROFT I. , SMITH R. J.
Published: December 2006

The positions of the cleavage sites of several restriction endonucleases were mapped in DNA isolated from the cyanophages A‐1L, A‐4L, AN‐10, AN‐13 and AN‐23, which were replicated in Anabaena PCC 7120. Similarities within the maps show AN‐13 and AN‐23 to be closely related strains. A‐1L and AN‐10 also appear to be related, but show more divergence. The maps of A‐1L and AN‐10 are circular, apparently as the result of circular permutation of sequences. The maps of the other cyanophages are linear.
Rooting and establishment of Calabrian pine plantlets propagated in vitro: influence of growth substances, rooting medium and origin of explant
Authors: ABDULLAH A. A. , GRACE J. , YEOMAN M. M.
Published: December 2006

The effect of auxins and a cytokinin on induction of roots in cultured axillary shoots of Pinus brutia Ten, has been tested. Auxin was crucial for root initiation and the rooting response varied according to the type and concentration of auxin applied. Both auxin and cytokinin and the interactions between them affected the quantity and quality of the induced roots. Aerated non‐sterile tap water was an effective rooting medium, comparable to agar. After planting out into soil, some of the influences of auxin and cytokinin could still be seen after six months. However, roots developed normally in the soil, displaying dichotomous lateral branches. The results draw attention to the need for care in the choice and application of the medium for the initial induction of roots. Results of greenhouse trials indicated that the most vigorous plants were obtained via the axillary shoots.
THE SUBCELLULAR DISTRIBUTION OF ENDOGENOUS AND EXOGENOUS SEROTONIN IN BRAIN TISSUE: COMPARISON OF SYNAPTOSOMES STORING SEROTONIN, NOREPINEPHRINE, AND γ‐AMINOBUTYRIC ACID1
Authors: Kuhar M. J. , Shaskan E. G. , Snyder S. H.
Published: December 2006

Abstract— We have studied the subcellular distribution of exogenous and endogenous serotinin in slices from the hypothalamus and midbrain of several species. In a procedure which appears to label the endogenous pools, tissue slices were incubated with low concentrations of [3H]5‐HT (5 × 10‐8 M), for 45 min, when there was apparent equilibrium between [3H]5‐HT of tissue and medium. After the tissue slices were homogenized in 0‐32 M‐sucrose and subjected to differential centrifugation, the distribution of exogenous and endogenous 5‐HT in pellets and supernatant fluid was similar.

In some experiments, the crude mitochondrial pellets were resuspended in 0‐32 M‐sucrose, layered on linear, continuous density gradients of sucrose (1 ‐5‐0‐32 M), and centrifuged for short times (incomplete equilibrium centrifugation). The subcellular distribution of particulate tritium, total tritium, and particulate endogenous 5‐HT was the same in portions of the gradients containing synaptosomes. The peak distribution of [3H]5‐HT in sucrose gradients was separable from the peak for [14C]GABA by four to five fractions; potassium (a marker for cytoplasm occluded within synaptosomes) occurred in the regions of the gradients containing most of the labelled compounds. The distribution of monoamine oxidase activity (a mitochondrial marker) overlapped the distribution of [3H]5‐HT after a 15 min centrifugation but appeared in denser regions of the gradient after centrifuging for 2 h. Particles containing [3H]5‐HT and [I4C]NE were slightly but consistently separable in synaptosomal fractions isolated from the hypothalamus or midbrain of rat, guinea pig and hamster.
PURIFICATION AND SOME PROPERTIES OF S‐100 PROTEIN FRACTIONS FROM SHEEP AND PIG BRAINS
Authors: Uyemura K. , Vincendon G. , Gombos G. , Mandel P.
Published: December 2006

Abstract— The S‐100 protein fraction of pig and sheep brain was purified in 40 per cent yield by a modification of the procedure of Moore (1965), which avoided selective loss of S‐100 components. The S‐100 fraction of both pig and sheep is a mixture of proteins as indicated by acrylamide gel electrophoresis and N‐terminal amino acid analysis. Differences in amino acid composition, electrophoretic heterogenity and N‐terminal analysis were found.

One fraction (fraction A) was isolated by DEAE‐Sephadex chromatography from pig brain S‐100 protein fraction. It was considered to be a single protein since it migrated as a single band on acrylamide gel electrophoresis and showed a single symmetrical peak during ultracentrifugal analysis. Only one N‐terminal amino acid was detected in fraction A. The amino acid composition of this fraction showed minor but significant differences from that of the complete S‐100 protein fraction from pig brain. The S‐100 protein fraction of both species, as well as fraction A, had similar s20, w values and similar molecular weights (about 20,000) as indicated by gel filtration. These results, together with the immunological data obtained by other authors, suggest that the proteins of the S‐100 fraction are closely related; the heterogeneity of the S‐100 protein fraction may be of the same type as the lactate dehydrogenase isoenzymes.
ASPECTS OF ACETYLCHOLINE METABOLISM IN THE ELECTRIC ORGAN OF TORPEDO MARMORATA
Authors: Marchbanks R. M. , Israël M.
Published: December 2006

Abstract— —The synthesis of acetylcholine and its compartmentation were studied in the electric organ of Torpedo marmorata. When electric organ was homogenized in iso‐osmotic NaCl‐sucrose some 55 per cent of its acetylcholine content was lost unless very potent cholinesterase inhibitors were present. Slices of electric organ incubated in a suitable medium were found to synthesize radioactive‐labelled acetylcholine from [N‐Me‐3H] choline. The specific activity of the labelled acetylcholine was higher in the trichloracetic acid extract of the organ slices than in an NaCl‐sucrose homogenate. Acetylcholine‐containing vesicles isolated from the NaCl‐sucrose homogenate contained labelled acetylcholine with about the same specific activity as the parent homogenate. There was thus a fraction of acetylcholine in the incubated tissue of higher specific radioactivity that was lost when the tissue was homogenized. The acetylcholine‐containing vesicles lose their acetylcholine when submitted to gel filtration under hypo‐osmotic conditions. On standing at 5°C there were only small losses of acetylcholine from the vesicles but at 20°C the losses were substantial. Vesicles containing labelled acetylcholine were studied. On gel filtration under iso‐osmotic conditions there was a considerable loss of labelled acetylcholine without a concomitant loss of bio‐assayable acetylcholine. The pools of radioactive and bio‐assayable acetylcholine are therefore not homogeneous in the vesicles as isolated.
BRAIN SPHINGOGLYCOLIPIDS IN KRABBE'S GLOBOID CELL LEUCODYSTROPHY1
Authors: Eto Y. , Suzuki K.
Published: December 2006

Abstract— Seven sphingoglycolipids were isolated from the white matter of a patient with globoid cell leucodystrophy (Krabbe's disease). After purification by saponification and column and preparative thin‐layer chromatography, these compounds were analysed for the carbohydrate composition and sequence and for fatty acid composition by paper and gas‐liquid chromatography. The compounds were identified as gluco‐ and galactocerebrosides, lactosyl‐ceramide, digalactosy I‐glucosyl‐ceramide, two types of tetrahexosyl‐ceramides (asialo‐ganglioside and globoside), and sulphatide. Glucocerebrosideconstituted 13 percent of total cerebroside in white matter, but sulphatide contained only galactose. Galactocere‐broside and sulphatide exhibited compositions of fatty acids similar to those in normal white matter, with only minor abnormalities. Other sphingoglycolipids showed fatty acid patterns with relatively high proportions of longer‐chain fatty acids, rather than the predominant C18:0 acid usually found in ceramide hexosides of the brain. Hematoside, also found in the white matter in a significant amount, similarly contained a large proportion of longer‐chain fatty acids, whereas other gangliosides contained predominantly C18:0 acid. The abnormal ceramide hexoside pattern was restricted mostly to white matter except for glucocerebroside, which constituted 32 per cent of grey matter cerebroside. We postulate that the visceral type of sphingoglycolipids may be constituents of globoid cells, abundantly present in white matter and considered to be cells of mesenchymal origin.
AMINO ACID INCORPORATION INTO PROTEIN IN NEURONAL CELL BODY AND NEUROPIL FRACTIONS IN VITRO
Authors: Tiplady B. , Rose S. P. R.
Published: December 2006

Abstract—

The incorporation of radioactivity from [3H]lysine into acid‐insoluble material in vitro in mixed cell suspensions and isolated neuronal and neuropil fractions has been followed.

In the mixed cell suspension, incorporation was linear in fresh preparations for up to 60 min. In cold stored preparations, incorporation began to fall off after 30 min. Incorporation, at 4‐11 pmol/mg protein/h, was intermediate between that in the tissue slice and in a cell‐free preparation. Addition of a mixture of non‐labelled amino acids at 1 mM produced a 30‐40 per cent inhibition of incorporation. Molar rates of incorporation of glutamate and tryptophan into the mixed cell fractions were respectively 73 and 1‐4 times that of lysine.

Only 8 per cent of the incorporated radioactivity could be recovered in soluble as opposed to particulate material. After hydrolysis of the protein, followed by paper chromatography and autoradiography, radioactivity was detected only in the position corresponding to lysine.

Incorporation in the separated cell fractions was not markedly reduced by the centri‐fugation procedure. Incorporation into the neuronal fraction was 2‐2‐6 times that into the neuropil fraction, depending on the amino acid used. Incorporation into both was reduced by some 40 per cent by addition of an amino acid mixture.

Comparison of in vivo and in vitro data suggest that the differences in rate of incorporation are characteristic of neurons and neuropil in situ.
PURIFICATION AND PROPERTIES OF MITOCHONDRIAL MONOAMINE OXIDASE IN BEEF BRAIN
Authors: Harada M. , Mizutani K. , Nagatsu T.
Published: December 2006

Abstract— Monoamine oxidase was purified approximately 40‐fold from beef brain mitochondria. The purification procedure involved extraction with a non‐ionic detergent (Nonion NS‐210) after heat treatment, ammonium sulphate fractionation, chromatographies on DEAE‐cellulose and Sepharose 6B, and a continuous flow electrophoresis. A major component (enzyme 1) with a higher specific activity and a minor component (enzyme 2) with a lower specific activity were separated. Properties of both enzymes towards kynuramine including pH‐optimum and Km values were similar, but the enzyme 1 had the higher specific activity towards tyramine whereas that of enzyme 2 was towards normetane‐phrine. Fluorescence spectra indicated that the enzyme 1 is a flavoprotein. Copper was not detected, and copper chelating agents did not inhibit the enzyme. p‐Chloromercuribenzoate and JV‐ethylmaleimide inhibited the enzyme, indicating the presence of the essential SH‐groups.
THE EFFECTS OF INHIBITORS OF PROTEIN SYNTHESIS ON INCORPORATION OF LIPIDS INTO MYELIN12
Authors: Benjamins Joyce A. , Herschkowitz N. , Robinson June , McKhann G. M.
Published: December 2006

Abstract— Following intracranial injections of puromycin, the incorporation of [3H]leucine into brain protein was inhibited by 80 per cent. Conversely, incorporation of [35S]sulphate into sulphatide or [2‐3H]glycerol into phosphatidyl choline was not inhibited. Under these conditions, appearance of labelled protein in myelin was inhibited by 90 per cent, while the appearance of newly labelled sulphatide and phosphatidyl choline in myelin membrane was not greatly affected. Experiments with cycloheximide gave similar results with phosphatidyl choline, but incorporation of [35S]sulphate into total sulphatide was decreased by about 30 per cent in animals given cycloheximide. Neither puromycin nor cycloheximide had any inhibitory effect on galactocerebroside sulphotransferase.
THE COMPOSITION OF LIPIDS IN CEREBROSPINAL FLUID OF CHILDREN AND ADULTS
Authors: Illingworth D. R. , Glover J.
Published: December 2006

Abstract— The proportions of esterified cholesterol and phosphatidyl ethanolamine in lipids of cerebrospinal fluid (CSF) from children were found to be lower than the corresponcling values for adult CSF. The fatty acid patterns of the cholesterol ester, triglyceride + non‐esterified fatty acids and phospholipid fractions all displayed low proportions of linoleate; palmitate and oleate were the principal acids present. The fatty acid composition of these lipid classes for CSF derived from children was similar to that from adult subjects. Degradation of CSF lecithin by snake‐venom phospholipase A2 revealed the saturated acids to be located predominantly in the 1‐position with the unsaturated ones mainly in the 2‐position.
POTENTIATION OF AMP‐AMINOHYDROLASE ACTIVITY OF BRAIN MITOCHONDRIA BY HEXOKINASE
Authors: Buniatian H. Ch. , Haroutunian A. V.
Published: December 2006

Abstract— The addition of hexokinase (yeast and brain) to mitochondrial fractions of brain (rat) resulted in a considerable increase of formation of ammonia from AMP. The mechanisms underlying the activation of AMP‐aminohydrolase of brain mitochondria by ATP and hexokinase are quite different. In the activation of AMP‐aminohydrolase by hexokinase the SH‐groups of both enzymes particularly of the latter are of importance. Brain mitochondria contain low‐molecular dialysable substances of unknown nature which are necessary for the interaction of both enzymes.
THE COMPARATIVE EFFECTS OF VARIOUS HYDRA‐ZIDES ON γ‐AMINOBUTYRIC ACID AND ITS METABOLISM
Authors: Wood J. D. , Abrahams Dawne E.
Published: December 2006

Abstract— The administration of different hydrazides to chicks (20‐23 days post‐hatching) in amounts giving similar latent periods before the onset of seizures produced (i) similar rates of decrease in content of cerebral GABA, (ii) considerable but dissimilar inhibitions of cerebral GAD activity, (iii) slight inhibitions of cerebral GABA‐T activity. The results support the view that low GABA levels were involved in. the etiology of the seizures but seemed to rule out the possibility that a reduced turnover of GABA was responsible for the occurrence of the convulsions.
BRAIN LIPIDS OF MICE HOMOZYGOUS FOR THE GENE‘DILUTE LETHAL’(d1)
Authors: Winterbourn C. C. , Woolf F. , Woolf L. I.
Published: December 2006

Abstract— The lipid composition of brains of mice homozygous for the gene‘dilute lethal’and aged 13‐26 days has been determined. This period covers the early stages of myelination up to the time of death. The brains of affected mice contained up to 8 per cent less total lipid than normal. The lipids increasing most rapidly at this age period were most affected; cerebroside, which normally increased six‐fold between the 14th and 24th days of life, was as much as 25 per cent below normal, but there was no significant reduction in non‐myelin lipids. Studies with [l‐14C]acetate suggested that the low levels of lipids reflected decreased rates of synthesis. In contrast to other reports, no myelin breakdown could be detected, either by TLC for cholesterol esters or histologically. The lowest levels of lipids and slowest rates of cerebroside synthesis occurred in the smallest affected mice; we suggest that the abnormalities in brain lipids reflect a reduced growth rate caused by poorer nutrition in the affected mice.
QUANTITATIVE HISTOCHEMISTRY OF GLUTAMATE DECARBOXYLASE IN THE RAT HIPPOCAMPAL REGION
Authors: Storm‐Matheen J. , Fonnum F.
Published: December 2006

Abstract— The distribution of glutamate decarboxylase (GAD) was studied in hippocampus regio superior and in area dentata. In both regions the enzyme showed a bimodal distribution profile with peak activities in the molecular and pyramidal layers of hippocampus, and in the molecular and granular layers of area dentata. The pyramidal and granular layers contain the terminals and perikarya of inhibitory intrinsic neurones, the basket cells. The molecular layers contain neurones of similar morphology but with unknown function. GAD showed a very low activity in fimbria, a major pathway of fibres efferent and afferent to the hippocampal region.

The data are consistent with GAD being concentrated within the inhibitory local neurones of the hippocampal region.
β‐Ar‐ACETYL D‐GALACTOSAMINIDASE IN BULK SEPARATED NEURONS AND NEUROPIL FROM RAT CEREBRAL CORTEX
Authors: Sinha A. K. , Rose S. P. R.
Published: December 2006

Abstract— β‐N‐Acetyl D‐galactosaminidase was studied in isolated neuronal and neuropil fractions from cerebral cortex and subcellular fractions derived from them. Although the enzyme activity evinced some latency properties, its subcellular distribution pattern was broader than that observed with other acid hydrolases. By contrast with nine other acid hydrolases, it was more active in neuropil than neuronal fractions (neuronal/neuropil activity ratio 0.63). This ratio was preserved in lysosomal subfractions derived from the isolated cell fractions. The data is taken as further evidence for the microheterogeneity of lysosomal particles from the brain.
CHLORAMPHENICOL‐ AND CYCLOHEXIMIDE‐SENSITIVE PROTEIN SYNTHETIC SYSTEMS IN BRAIN MITOCHONDRIAL AND NERVE‐ENDING PREPARATIONS
Authors: Deanin Grace G. , Gordon M. W.
Published: December 2006

Abstract— Mitochondria isolated from rat brain contained ribosomes, with an apparent sedimentation constant (j) of 60, which were dissociable into 45s and 32s subunits. The RNA associated with the 45s subunit had an s value of 16; the RNA of the 32s subunit had an s value of 13. These values were essentially like those found for the mitochondria of rat liver. Nascent protein associated with the 60s monosome was reduced by chloramphenicol but not by cycloheximide. All cycloheximide‐sensitive activity found in brain mitochondria prepared from sucrose or Ficoll‐sucrose gradients and most of that associated with nerve‐ending preparations that were similarly prepared could be attributed to a contaminant that was probably a membrane‐enclosed, cytoplasmic‐like system which contained, in addition to 18s and 28s RNA, one or more mitochondria. Nerve‐ending preparations from which most or all of this contamination had been removed exhibited very little cycloheximide‐sensitive protein synthetic activity.
THE ASSOCIATION OF LESION‐INDUCED REDUCTIONS IN BRAIN MONOAMINES WITH ALTERATIONS IN STRIATAL CARBOHYDRATE METABOLISM1
Authors: Hoffmann P. C. , Toon R. , Kleinman J. , Heller A.
Published: December 2006

Abstract— –Changes in glycogen, glucose, lactate and monoamine levels in various brain structures were studied after unilateral diencephalic lesions in the rat. These lesions were placed to transect the fibres of the medial forebrain bundle within the lateral hypothalamus as well as to encroach upon the medial aspect of the internal capsule. Such lesions are known to produce unilateral reduction of telencephalic monoamines rostral to the lesion. In paraformaldehyde‐perfused brain, the level of glycogen increased by 30 per cent (+0 82 μmol/g) in the caudate nucleus ipsilateral to the lesion in comparison to that in the caudate of the non‐lesioned side. Other telencephalic areas, as well as cerebellum and brainstem, showed no significant change in glycogen levels. In brains from unanaesthetized rats, frozen 15–30 s after decapitation (to simulate anoxia, with consequent glycogen mobilization), a caudate‐containing sample from the lesion side had 31 per cent (+0 51 μmol/g) more glycogen than a comparable sample from the control side. Glucose levels were also elevated by 72 per cent (+0 05 μmol/g, whereas lactate levels were not significantly changed. Similar samples obtained from animals 3anaesthetized with phenobarbital for 2 h prior to killing showed a 76 per cent increase in glycogen in both lesion and control caudate nuclei when compared to those obtained from the unanaesthetized group. Glycogen levels were increased by 15 per cent (+0 41 μmol/g) and glucose by 72 per cent (+0 31 μmol/g) on the lesion side in comparison to the values obtained from the control side in the anaesthetized group. Lactate levels were not significantly affected. The dopamine levels in these caudate samples from the lesion side were reduced by 97 and 88 per cent in the unanaesthetized and anaesthetized animals, respectively. In samples of caudate allowed to glycolyse under anoxic conditions for 10 min, the amount of lactate found on the lesion side was increased 29 per cent over that found in identical samples from the non‐lesioned side. Dopamine was reduced by 78 per cent in these samples. The remaining telencephalic areas exhibited no significant side to side difference in lactate levels despite a 71 per cent decrease in their levels of norepinephrine. These findings demonstrate that glycogen metabolism in the neostriatum is affected by diencephalic lesions which result in a loss of striatal monoamines, observations suggesting that brain biogenic amines may play a role in the regulation of neuronal metabolism in the neostriatum.
EFFECT OF VINBLASTINE AND COLCHICINE ON UPTAKE AND RELEASE OF PUTATIVE TRANSMITTERS BY SYNAPTOSOMES AND ON BRAIN ACTOMYOSIN‐LIKE PROTEIN
Authors: Nicklas W. J. , Puszkin S. , Berl S.
Published: December 2006

Abstract— The effects of several inhibitors, including vinblastine and colchicine, on the accumulation of a number of putative transmitters by a rat brain synaptosomal preparation and their subsequent release by excess K+ was examined. In addition, the effect of the alkaloids on the ATPase activity of the actomyosin‐like protein, neurostenin, isolated from the synaptosomal preparation, was studied. The uptakes of radioactive glutamate, GABA, dopamine and norepinephrine were energy‐dependent, as evidenced by their susceptibility to 0.01 mM carbonyl cyanide m‐chlorophenylhydrazone (Cl‐CCP), 01 mM ouabain and temperature. The active accumulations of GABA, dopamine and norepinephrine were also greatly inhibited by 1 mM6‐hydroxydopamine (6‐OHDA), 01 mM mersalyl, 0.05–0.25mM vinblastine and 0.1–1.0 mM colchicine. Vinblastine was approximately 10‐fold more potent (K1, −0.1 mM) than colchicine as an inhibitor. The release of actively accumulated dopamine or norepinephrine by excess K+ (increasing the [K+] from 5 to 30 mM) was inhibited somewhat when vinblastine was present during the entire incubation period. If the synaptosomes were preloaded with the radioactive compounds prior to addition of vinblastine, there was no discernible effect on the relative amount of material released by excess K+. However, the addition of inhibitor under the latter conditions caused a leakage of radioactivity into the medium even without excess K+ being present. Glutamate accumulation was somewhat different from that of GABA, dopamine or norepinephrine. Although it required energy for uptake, 6‐OHDA, mersalyl, vinblastine or colchicine were not inhibitory. Studies of the oxidative metabolism of glutamate and GABA by this synaptosomal preparation indicated that the mechanisms of inhibition by vinblastine was not attributable to a metabolic effect. Both vinblastine and colchicine inhibited the Mg2+‐stimulated, but not the Ca2+‐activated ATPase of neurostenin. This effect was probably attributable to an interaction of the vinblastine with the neurin moiety of this actomyosin‐like protein. We suggest that the inhibitory phenomena exhibited by vinblastine and colchicine in this synaptosomal preparation arose from the effect of these alkaloids on the neurin associated with the synaptic membrane.
CIRCULAR DICHROISM OF NERVE MEMBRANE FRACTIONS: EFFECTS OF TEMPERATURE, pH AND ELECTROLYTES1
Authors: Moore W. V. , Wetlaufer D. B.
Published: December 2006

Abstract— We have demonstrated significant differences in the circular dichroic (CD) spectra of myelin, synaptic vesicle and synaptosomal membrane preparations from rat brain. Although the measured CD spectra probably contained components attributable to turbidity, we have presented arguments to indicate that turbidity effects could not account for all the observed differences. We think it likely, therefore, that these three membrane fractions exhibit intrinsically different CD spectra, and therefore contain proteins of differing three‐dimensional structure. The perturbation of membrane CD produced by electrolytes appeared to involve specific ionic effects. Here again, effects of turbidity were probably involved. The increase in light scattering was demonstrated by an increase in A250 at increasing salt concentrations. The increase in A250 and the decrease in the intensity of [ø] showed no simple correlation. The effect of acidic pH (below pH 6–5) on the membrane CD appeared similar to that of increasing salt concentrations. In contrast, the effect of basic pH appeared to be one of denaturation. The effect of temperature on the membrane CD was one of stability below or at physiological temperatures and of irreversible instability at temperatures slightly above the physiological range. The CD of synaptosomal membrane preparations changed slowly over prolonged periods at low temperatures or by cycles of freezing and thawing. Our observations indicate that careful attention to the physical and chemical environment of membranes is necessary in CD investigations of membrane preparations.
BIOCHEMICAL STUDIES OF MYELIN IN WALLERIAN DEGENERATION OF RAT OPTIC NERVE1
Authors: Bignami A. , Eng L. F.
Published: December 2006

Abstract— Wallerian degeneration of the optic nerves of the rat was induced by removal of the eyes. After 54, 66, 76 or 90 days of degeneration a myelin fraction of the nerves was obtained by the procedure of Laatschet al. (1962). The yield of myelin from the degenerated nerves was decreased, but the isolated myelin appeared to be morphologically normal. The proportion of cholesterol in the myelin lipids was slightly increased, whereas that of the ethanolamineglycerophosphatides was decreased and galactolipids were normal. After one‘cycle’of myelin purification, the high‐molecular‐weight fraction formed a much greater percentage of the total protein in myelin isolated from degenerated optic nerves. After 2–3‘cycles’of purification, the distribution of protein in myelin isolated from degenerated and normal optic nerves was similar, an observation suggesting that the high‐molecular‐weight fraction in‘1‐cycle myelin’from degenerated optic nerves may have been partly attributable to contamination. With the possible exception of ethanolamineglycerophosphatides, our data suggest that there was no preferential breakdown of myelin lipid constituents nor of protein constituents during Wallerian degeneration of rat optic nerve. As assessed by SDS‐gel electrophoresis of the water‐insoluble particulate fraction, the percentage of myelin protein was markedly decreased after 76 days of degeneration. However, the major myelin protein constituents in this fraction (the two basic proteins and proteolipid protein) appeared to decrease in the same relative proportions.
ACCELERATED EFFLUX OF [14C] AND [3H] AMINO ACIDS FROM SUPERFUSED SLICES OF RAT BRAIN1
Authors: Crnic D. M. , Hammerstad J. P. , Cutler R. W. P.
Published: December 2006

Abstract— The rate of spontaneous efflux of several isotopically‐labelled amino acids was measured in superfused slices of rat brain. The group specificity of amino acid efflux was studied by examining the pattern of accelerated efflux in the presence of extracellular unlabeled amino acid. The mediated efflux of γ‐aminobutyric acid and l‐glutamic acid was highly specific. Less specificity was found for amino acids in the small neutral, large neutral and basic groups. The efflux of γ‐aminobutyric acid and l‐glutamic acid was accelerated by structurally similar amino acids which are known to depress or excite motor neurons. This finding raises the possibility that the physiological effects of non‐specific amino acids during local iontophoresis may be secondary to an accelerated release of more specific transmitter amino acids from neighbouring cells.
IN VITRO TRANSFORMATION OF DEHYDROEPIANDROSTERONE OR ITS SULPHATE INTO ANDROSTENEDIOL OR ITS SULPHATE BY RAT BRAIN AND BLOOD PREPARATIONS1,2
Authors: Kishimoto Y.
Published: December 2006

Abstract— –Enzymic transformation of [4‐14C]dehydroepiandrosterone or [4‐14C]dehydro‐epiandrosterone sulphate to androstenediol or its sulphate occurred when incubated with a microsomal preparation of rat brain or a whole rat blood homogenate. The brain enzyme which appeared to cause this transformation had a pH optimum at 60, was NADPH2‐dependent, and had an apparent Km of 4·6 × 10−6m. When the subcellular fractions of rat brain were compared for transformation, microsomes had the highest specific activity, followed by the cytosol. The crude nuclear and mitochondrial fractions had no significant activity. The level of enzymic activity in the brain microsomes increased from that for rats sacrificed at 7 days of postnatal age to a maximum for rats sacrificed at 1 month of age; then the activity appeared to level off in rats older than 1 month. Microsomes obtained from the cerebellum had the highest specific activity in comparison to that obtained from the cerebral cortex, the diencephalon, and the brain stem. The incubated preparations of rat brain also converted dehydroepiandrosterone sulphate to androstenediol sulphate without hydrolysis.

The enzyme in rat blood which was similar to that in the brain was also partially characterized. The blood enzyme had a pH optimum at 6–5, was nearly exclusively present in erythrocytes, was also NADPH2‐dependent, and had an apparent Km of 2·7 × 10−4m. The developmental pattern of the blood enzyme specific activity was similar to that of the rat brain enzyme. Upon haemolysis, most activity was recovered in the haemolysate.
THE USE OF MICROWAVE HEATING TO INACTIVATE CHOLINESTERASE IN THE RAT BRAIN PRIOR TO ANALYSIS FOR ACETYLCHOLINE
Authors: Stavinoha W. B. , Weintraub S. T. , Modak A. T.
Published: December 2006

Abstract— Heating with 2450 MHz microwave radiation has been investigated as a means for animal sacrifice concurrent with enzyme inactivation. Uniform inactivation of cholinesterase (EC 3.1.1.8) in the entire brain can be effected in the rat within 4 s and in the mouse within 2 s without destruction of acetylcholine. The acetylcholine content in the whole brain of a rat was found to be 25.4 ± 1.5 nmol/g after irradiation, in comparison to 13.8 ± 1.7 nmol/g after standard methods of sacrifice. In the mouse whole brain, the comparable acetylcholine contents were 25.5 ± 2.6 and 13.7 ± 1.7 nmol/g, respectively. The value of this procedure for rapid inactivation of enzymes in the study of acetylcholine turnover is discussed.
TRANSAMINATIONS BETWEEN AMINO ACIDS AND KETO ACIDS ELEVATED IN PHENYLKETONURIA AND MAPLE SYRUP URINE DISEASE
Authors: Lees G. J. , Weiner N.
Published: December 2006

Abstract— The transamination between amino acids and aliphatic and aromatic keto acids has been investigated in homogenates of human and rat brain. Tryptophan, phenylalanine and 3,4‐dihydroxyphenylalanine (DOPA) at concentrations of 3.6 min and below trans‐aminated aromatic keto acids more rapidly than α‐ketoglutarate; lower Km values were found for tryptophan and phenylalanine in the presence of the aromatic keto acid. Rat brain and liver arninotransferases exhibited similar affinities for tryptophan in the presence of different keto acids. Branched chain keto acids were also acceptors of the amino groups of tryptophan and DOPA. In brain homogenates α‐ketoglutarate and p‐hydroxyphenyl‐pyruvate were transaminated by tyrosine and 5‐hydroxytryptophan at about equal rates, whereas a‐ketoglutarate was transaminated more rapidly with aliphatic amino acids. At concentrations of 1.6 m DOPA and 0.8 mM p‐hydroxyphenylpyruvate, transamination was 6‐fold greater than the rate of formation of dopamine. The dihydroxyphenylpyruvate formed during arninotransfer from DOPA by brain tissue was not readily decarboxylated, whereas 65–70 per cent of the indolepyruvate formed from tryptophan was decarboxylated. We suggest that an increased rate or degree of transamination between tryptophan and aromatic and branched chain keto acids may explain the increased excretion of non‐hydroxylated indolic acids in phenylketonuria and‘maple syrup urine’disease, respectively. Increased aminotransfers from tryptophan and DOPA may reduce the amounts of precursors available for the synthesis of serotonin and catecholamines, both of which are at low levels in the sera of untreated phenylketonurics.
SUBCELLULAR FRACTIONATION OF POSTMORTEM BRAIN1
Authors: Swanson P. D. , Harvey F. H. , Stahl W. L.
Published: December 2006

Abstract— Procedures used to separate subcellular organelles from fresh brain were applied to brains which had been removed from guinea pigs (1) immediately after death; (2) after the dead animal was maintained at room temperature for 3 h, followed by 16–17 h at 4°C; or (3) after the dead animal was maintained for 19–20 h at room temperature. Subcellular fractionation of the brains in 0.32 M sucrose was followed by discontinuous density gradient centrifugation of the crude mitochondrial fraction. After overnight storage of brains at room temperature, there was a moderate shift in succinate dehydrogenase activity from sub‐fraction C (mitochondria) to subfraction B (synaptosomes). There was little change in the distribution of galactolipid among particulate subfractions. There was little change in distributions of monoamine oxidase or acetylcholinesterase activities. Under the less extreme postmortem conditions, there were no shifts in the subcellular distributions of brain enzymes. Ultrastructural changes were much more profound and consisted of losses of identifiable mitochondria and synaptosomes and a progressive increase in very dense bodies. Our results suggest that in spite of the marked morphological changes, meaningful separation of subcellular organelles can be achieved with postmortem tissue.
CARBOHYDRATE METABOLISM IN BRAIN DURING CONVULSIONS AND ITS MODIFICATION BY PHENOBARBITONE1
Authors: King Lucy J. , Carl Juanita L. , Lao Lauro
Published: December 2006

Abstract— Assays of citric acid cycle substrates and metabolites of the second stage of the glycolytic pathway have completed a series of studies of glucose metabolism in brains of mice rapidly frozen at intervals during electrically‐induced, tonic‐clonic convulsions. Citric acid cycle metabolism reached a new equilibrium at a significantly higher rate. However, oxidative metabolism did not keep up with the demand for energy supplies, as indicated by an increasing lactate level and an increasing lactate: pyruvate ratio. Administration of a sub‐anaesthetic but anticonvulsant dose of phenobarbitone prior to convulsive electrical stirnulation was associated with as great an increase in anaerobic glycolysis as in mice given no drug prior to stimulation; but oxidative metabolism was not enhanced, as reflected by even greater lactate: pyruvate ratios in mice given phenobarbitone than in mice given no drug prior to convulsive stimulation.
THE UPTAKE OF γ‐[3H]AMINOBUTYRIC ACID BY SLICES FROM VARIOUS REGIONS OF RAT BRAIN AND THE EFFECT OF LITHIUM
Authors: Bond P. A.
Published: December 2006

Abstract— Slices from various regions of rat brain, incubated at 25°C, rapidly accumulate [3H]GABA from the surrounding medium until after 60min tissue:medium ratios as high as 300 may be achieved. Kinetic analysis has demonstrated two distinct uptake systems for GABA in all the brain regions examined. One system has a relatively high substrate affinity (Km= 1.2 ± 10‐5 M) while the other has a lower affinity (Km= 4 ± 10‐4 M). Studies at low GABA concentration (5 ± 10‐8 M), as well as estimates of maximum velocities, have shown that the distribution of the high affinity uptake system is heterogeneous. Cortex, hypothala mus, midbrain and hippocampus have relatively high uptake rates while the striatum, cerebellum and pons and medulla have a lower uptake rate. Maximum velocities for the low affinity uptake system show much less regional variation.

Lithium, either added to the incubation medium or fed to rats, had no effect on the uptake of GABA by cortical slices.
3‐METHOXY‐4‐HYDROXYPHENYLETHANOL IN THE RAT BRAIN
Authors: Braestrup C.
Published: December 2006

Abstract— The neutral dopamine metabolite, 3‐methoxy4hydroxypenylethanol (MOPET) can be measured in the rat brain by a GLC method using a pentaflouropropionic derivative and electron capture detector. The identity of MOPET is verified by mass spectrographic analyses.

The endogenous level of MOPET of 16.6 ng/g whole rat brain can be raised more than four‐fold by intraperitoneal injection of L‐DOPA, dopamine or MOPET. In contrast intraventricular injection of dopamine or intraperitoneal injection of L‐DOPA plus a peripheral decarboxylase inhibitor (Ro 4‐4602)., results in small and insignificant increase bf MOPET in the CNS.

It is concluded that MOPET is probably of low significance to central dopamine metabolism and that MOPET found in the rat brain is predominantly of peripheral origin.
GLYCOGEN AND GLYCOGEN PHOSPHORYLASE IN THE CEREBRAL CORTEX OF MICE UNDER THE INFLUENCE OF METHIONINE SULPHOXIMINE
Authors: Folbergrovaa Jaroslava
Published: December 2006

Abstract— Glucose and glycogen levels in the mouse cerebral cortex in vivo were studied after recovery from methionine sulphoximine seizures. The animals appeared normal 24 h after methionine sulphoximine administration but both glucose and glycogen still persisted at higher levels 72 h after injection (by 64 and 275 per cent, respectively). When seizures were prevented by methionine, the increase in glucose and glycogen at the longer time intervals was significantly smaller than in animals treated with methionine sulphoximine only; glucose reached normal values at 48 or 72 h; the accumulation of glycogen was reduced by about three to five times, but after 72 h the levels were still significantly higher than in control animals (67 or 32 per cent increase, depending on the administered dose of methionine).

In contrast to the considerable accumulation of glycogen after administration of methionine sulphoximine in vivo, it had no effect on the level of glycogen in brain cortex slices in vitro. After 3 h incubation in the absence of methionine sulphoximine, glycogen was resynthesized to a level of about 4 μmol/g wet tissue and this value was not significantly affected by the presence of various concentrations of methionine sulphoximine in the incubation medium (10‐5 to 10‐2 M). The total (a+b forms) phosphorylase activity of mouse cerebral cortex in vivo after methionine sulphoximine administration was not affected. The fraction of active phosphorylase was reduced by about 50 per cent at the time of seizures. When seizures were prevented by methionine, the decrease in active phosphorylase was also completely prevented. In the preconvulsive period (1‐2 h) and after recovery from the seizures (48 h after methionine sulphoximine administration) active phosphorylase was normal. The possible mechanisms involved in the increased accumulation of glycogen after methionine sulphoximine administration are discussed.
EFFECT OF DIBUTYRYL‐CYCLIC AMP and DEXAMETHASONE ON NORADRENALINE SYNTHESIS IN ISOLATED SUPERIOR CERVICAL GANGLIA
Authors: Keen P. , McLean W. G.
Published: December 2006

Abstract— Incubation with dibutyryl‐cyclic AMP increased levels of both noradrenaline and dopamine‐β‐hydroxylase in isolated rat superior cervical ganglia. Dexamethasone also increased the dopamine‐β‐hydroxylase content but did not affect noradrenaline levels. Cycloheximide blocked the effect of dibutyryl‐cyclic AMP on ganglion dopamine‐β‐hydroxylase but did not affect the rise in noradrenaline content.

Dibutyryl‐cyclic AMP increased the synthesis of noradrenaline from [14C]tyrosine but not from [3H]DOPA.

The results are discussed in terms of a possible role for cyclic AMP in the control of noradrenaline synthesis in sympathetic ganglia.