bluuebunny/crossref_metadata_2025_split huggingface dataset:
POLYUNSATURATED FATTY ACID METABOLISM IN NEUROBLASTOMA CELLS IN CULTURE1
Authors: Yavin E. , Yavin Ziva , Menkes J. H. 
Published: October 2006

Abstract—Neuroblastoma cell cultures took up linoleic and linolenic acids at approximately equal rates, and incorporated them into a variety of lipid fractions, principally cellular phospholipids. Linoleic acid was preferentially incorporated into choline phosphoglycerides, while most of the radioactivity derived from linolenic acid entered ethanolamine phosphoglycerides. There was no evidence for direct transfer of fatty acids between these two phosphoglyceride fractions. When, after the addition of cytosine arabinoside, cell division was arrested, the entry of labelled fatty acids into ethanolamine and serine phosphoglycerides was reduced, suggesting that these lipids are involved in the formation of new cell membranes.In the ethanolamine phosphoglyceride fraction, phosphatidal ethanolamine (plasmalogen) was the principal acceptor for the higher polyunsaturated fatty acids of the φ 3 series. The ratio of labelled fatty acids entering ethanolamine plasmalogens to that entering ethanolamine phosphoglycerides increased following the addition of cytosine arabinoside, suggesting plasmalogens to be involved in formation of cell processes.The first step in the metabolism of both linoleic and linolenic acid was the addition of a two‐carbon unit. Conversion of linoleic acid to higher polyunsaturated fatty acids was slower than the conversion of linolenic acid to its higher analogues. This contrasted with the behaviour of dissociated cultures of normal brain cells which were able to form higher analogues of linoleic and linolenic acids at nearly equal rates.
THE EFFECTS OF AGE AND ALCOHOL ON (Na++ K+)‐ATPASE ACTIVITY OF WHOLE HOMOGENATE AND SYNAPTOSOMES PREPARED FROM MOUSE AND HUMAN BRAIN
Authors: Sun A. Y. , Samorajski T. 
Published: October 2006

Abstract—Whole homogenates of mouse brain and nerve‐ending fractions of mouse and human brain were obtained at various age levels representative of maturity and old age. The mice were 3, 8 and 26–29 months old and the humans ranged in age from 19 to 84 y. Measurements of (Na++ K+)‐ATPase in whole brain homogenate of mouse did not reveal any significant differences in relation to age. However, the ability of ethanol at various concentrations to inhibit membrane‐bound synaptosomal (Na++ K+)‐ATPase was significantly greater in older mice and humans. The data are interpreted as indicating a change in the property of synaptic membranes as a consequence of advancing age.
SUPEROXIDE DISMUTASE OF MAMMALIAN NERVOUS SYSTEM
Authors: Fried R. , Mandel P. 
Published: October 2006

Abstract—Superoxide dismutase was assayed in portions of the nervous system (a) by inhibition of tetrazolium reduction by oxygen radicals, generated enzymically, and (b) by inhibition of tetrazolium reduction by oxygen radicals generated by oxidation of NADH in presence of phenazine methosulphate. Superoxide dismutase activity was found in beef brain, retina and adrenal medulla, as well as in brain, retina and lungs of adult and of newborn rats. Preliminary experiments with rats exposed to hyperbaric oxygen showed no alteration of enzyme activities in tissues of newborn and adult animals. The possible role of superoxide dismutase in the nervous system is discussed.
FUNCTIONAL COMPARTMENTS OF ADENINE NUCLEOTIDES SERVING AS PRECURSORS OF ADENOSINE 3′,5′‐MONOPHOSPHATE IN MOUSE CEREBRAL CORTEX
Authors: Skolnick P. , Daly J. W. 
Published: October 2006

Abstract—Cyclic AMP accumulates in cerebral cortical slices from the C57B1/6J mouse incubated with the following stimulatory agents: norepinephrine, adenosine, veratridine and adenosine‐biogenic amine combinations. The results with slices labelled with radioactive adenine or adenosine provide evidence for the existence of distinct functional compartments of adenine nuclcotides which serve as precursors of cyclic AMP on stimulation with specific agents. Thus, in slices labelled with [14C]adenine or [3H]adenosine the ratio of [14C] to [3H]cyclic AMP was dependent on the stimulatory agent; with veratridinc the ratio was 1.4 while with adenosine the ratio was 3.0. In addition, a greater than 2‐fold difference in the ratio of endogenous/radioactive cyclic AMP was observed in adenine or adenosine‐labelled slices after incubation with veratridine, norepinephrine, adenosine or adenosine‐amine combinations; the lowest ratios after stimulation with veratridine and the highest after adenosine or adenosine‐amine combinations. The high ratio observed with adenosine was in part due to a quite marked incorporation of the stimulant, adenosine, into the accumulating cyclic AMP. Such distinct functional compartments of cyclic AMP precursors may represent different cell types and/or morphological entities within one cell type.
GANGLIOSIDES OF THE BOVINE NEUROHYPOPHYSIS
Authors: Clarke J. T. R. 
Published: October 2006

Abstract—The gangliosides of the bovine neurohypophysis were isolated and partially characterized. In terms of lipid‐sialic acid, the concentration of gangliosides in the tissue was 1465 nmol/g wet wt. On the basis of chromatographic properties, sugar composition and the products of neuraminidase‐treatment, the principal ganglioside (approx. 51 per cent of the lipid‐sialic acid) was identified as N‐acetylneuraminylgalactosyl‐ N‐acetylgalactosaminyl‐(N‐acetylneuraminyl)‐galactosyl‐ glucosyl‐ceramide (GDta). The gland also contained galactosyl‐N‐acetylgalactosaminyl‐(N‐acetylneuraminyl‐ N‐acetylneuraminyl)‐galactosyl‐glucosyl‐ceramide (GDtb), and a mixture of N‐glycolyl‐neuraminic acid‐containing disialogangliosides with unknown structures, in addition to smaller quantities of galactosyl‐N‐acetylgalactosaminyl‐(N‐acetylneuraminyl)‐ galactosyl‐glucosyl‐ceramide (GM1) and two glucosamine‐containing monosialogangliosides. Stearic acid was the principal fatty acid in all the gangliosides.
THE STIMULATION OF ARGININE PHOSPHOKINASE IN LOBSTER AXONS BY GABA
Authors: Maki Y. , Cooper J. R. 
Published: October 2006

Abstract—GABA at physiological concentrations has been shown to stimulate the synthesis of arginine phosphate in lobster walking nerves. This effect can be observed both in intact axons and in axonal homogenates. The stimulatory activity of GABA on the synthesis of arginine phosphate appears to be on the Vmax of arginine phosphokinase whereas in the reverse reaction the effect is referable to the Km of ADP.
A COMPARISON OF THE EFFECTS OF SCORPION VENOM TITYUSTOXIN AND OUABAIN ON THE RELEASE OF ACETYLCHOLINE FROM INCUBATED SLICES OF RAT BRAIN1
Authors: Gomez M. V. , Diniz C. R. , Barbosa T. S. 
Published: October 2006

Abstract—The increase in the release of acetylcholine (ACh) from cortical slices of rat brain elicited by the depolarizing agents, ouabain and tityustoxin (TsTX) was compared in the presence of tetrodotoxin, an inhibitor of Na+ transport and of ethyleneglycol tetraacetic acid, a specific chelator of Ca2+. TsTX stimulated the release of ACh independently of K1 but required both Na+ and Ca2+. Unlike ouabain, TsTX failed to inhibit the Na+, K+ ‐ATPase of rat brain homogenates. The uptake of 24Na+ and of 45Ca2+ by the slices was significantly enhanced by TsTX over the entire incubation period during which this process was compared to TsTX‐free controls. A hypothesis of TsTX action is proposed which differs from that necessary to explain the ACh releasing effect of ouabain.
AMINO ACID TRANSPORT INTO THE CEREBROSPINAL FLUID OF THE RAT1
Authors: Franklin G. M. , Dudzinski D. S. , Cutler R. W. P. 
Published: October 2006

Abstract—The concentrations of glycine and 6 other amino acids have been assayed in the CSF and plasma of the rat, and regional heterogeneity of CSF amino acid concentration has been found. Steady state flux rates into the cranial and spinal fluid compartments were determined during perfusion with amino acid free medium. The transfer of glycine from blood into both the cranial and spinal subarachnoid fluids was saturable with only several‐fold elevations of plasma glycine. The results are discussed with regard to the putative neurotransmitter function of glycine in the spinal cord.
ON THE ACTIVATION OF PLASMA MEMBRANE ECTO‐ENZYMES BY TREATMENT WITH NEURAMINIDASE
Authors: Trams E. G. , Lauter C. J. , Banfield W. G. 
Published: October 2006

AbstractIt had been proposed that sialyl‐residues on the surface of the cell control the activity of certain plasma membrane ecto‐enzymes. We have tested the effects of several established (or presumptive) ecto‐enzymes in tissue cultures of CNS‐derived cells.Application of neuraminidases to cultured mouse neuroblastoma (N‐18), neonatal Syrian hamster astrocytes (NN), human astrocytoma (Cox clone) and two lines of primary mouse astroblasts failed to change the activity of ecto‐ATPase and 5′‐nucleotidase. Only two of the seven neuraminidase preparations produced marked or moderate increases in inorganic pyrophosphatase, p‐nitrophenylphosphatase and cholinesterase. We have concluded that the stimulation of these enzymes was not due to removal of sialyl‐residues. We suggest that contaminants (haemolysins?) in neuraminidase preparations of Clostridium perfringens increased membrane permeability and facilitated substrate‐product translocation.
CHEMICAL COMPOSITIONS OF BRAIN AND MYELIN IN TWO PATIENTS WITH MULTIPLE SULPHATASE DEFICIENCY (A VARIANT FORM OF METACHROMATIC LEUKODYSTROPHY)1
Authors: Eto Y. , Meier C. , Herschkowitz N. N. 
Published: October 2006

Abstract—The lipid composition of the brain, including myelin, was studied in detail in two cases with a variant form of metachromatic leukodystrophy (multiple sulphatase deficiency type).In the white matter, the sulphatide concentration was 3–4 times higher than the normal level in both cases. There was a significant accumulation of cholesterol sulphate in the brain, liver and kidney of both cases. The ganglioside pattern in the grey and white matter was abnormal, with a higher proportion of GM3, GM2 and GD3‐gangliosides. Non‐lipid hexosamine contents were increased 1.5‐2 times in brain, 8–10 times in liver and 2–3 times in kidney. Increased amounts of glucocerobroside, ceramide lactoside and ceramide trihexoside were present in grey and white matter of both cases.Recovery of purified myelin from two patients’brains was much less than from control (1–20% in case 1 and 20–30% in case 2). The lipid composition of myelin was almost normal except for a higher proportion of sulphatide, with a decreased amount of cerebroside. The fatty acid compositions of myelin sulphatide and sphingomyelin were almost normal, while non‐hydroxy fatty acids of cerebroside contained less long‐chain fatty acids, as characterized by a significant increase of C16:0 and C18:0 fatty acids. The myelin polypeptide pattern by SDS‐disc gel electrophoresis showed a relative decrease of basic protein and of proteolipid protein.A possible mechanism of myelin loss in MSD is discussed.
THE EFFECTS OF PHENYLKETONURIC AND OTHER METABOLITES ON SULFATED GALACTOCEREBROSIDE SYNTHESIS IN VIVO AND IN CULTURE
Authors: Sprinkle T. J. , Rennert O. M. 
Published: October 2006

Abstract— Sulfated galactocerebroside synthesis was examined in vitro in mouse spinal cord cultures. This system permitted the study of the effects of phenylketonuric metabolites upon synthesis of a specific myelin component, sulfatide, formed early in postnatal development in mice. A significant reduction of Na235SO4 incorporation into myelin sulfatide was observed when spinal cord cultures were grown in the presence of 1000 μm‐l‐phenylalanine and 500 μm‐phenylpyruvate (51 and 700%, respectively). No reduction was observed with β‐phenyllactate (300 μm and) phenylacetate (250 μm). Light microscopy indicated that the phenylpyruvate and phenylalanine treated cultures were less extensively myelinated compared to control and β‐phenyllactate or phenylacetate treated cultures. The reduction of sulfatide synthesis by phenylpyruvate was shown to be reversible.Intracerebral bilateral injections (8 μg) of l‐phenylalanine, phenylpyruvate, α‐ketobutyrate, α‐ketoisocaproate, α‐ketoisovalerate, β‐phenyllactate, and phenylacetate in mice 8–15 days old, followed by i.p. administration of radioactive sulfate, resulted in significantly reduced incorporation (all P < 0.05) of sulfate into brain sulfatides with all compounds tested with the exception of β‐phenyllactate and phenylacetate. In adult mouse, phenylpyruvate treatment also resulted in a significant decrease in labelling of brain sulfatide.The effects of phenylpyruvate and other metabolites upon pyruvate oxidation in mouse brain homogenates were examined by measuring 14CO2 release from [1‐14C]pyruvate. Both phenylpyruvate and α‐ketoisocaproate at 1 × 10‐3 resulted in a decrease in 14CO2 produced, while phenylacetate and β‐phenyllactate had no effect.Sulfate incorporation into sulfatide was reduced by α‐ketoisocaproate and phenylpyruvate, and to a lesser extent by phenylalanine, α‐ketobutyrate, and α‐ketoisovalerate. Phenyllactate and phenylacetate had no effect, either in vivo, or in culture. This order of effectiveness may be related in part to the effects of these compounds on pyruvate oxidation.
THE EFFECT OF DIABETES, INSULIN AND WALLERIAN DEGENERATION ON LEUCINE METABOLISM OF ISOLATED RAT SCIATIC NERVES
Authors: Buse Maria G. , Herlong H. Franklin , Weigand Dorothy A. , Spicer S. S. 
Published: October 2006

Abstract– 14CO2 production and 14C incorporation into proteins was studied in isolated rat sciatic nerves during incubation with 0.1 mM‐[1‐14C]leucine. Rats were made diabetic with streptozotocin. Nerves from diabetic rats incubated with glucose oxidized more [14C]leucine than controls. This difference was abolished in the presence of insulin (1 mU/ml). The effects of diabetes and insulin on leucine oxidation could not be demonstrated in the absence of glucose. Insulin stimulated the incorporation of [14C] from leucine into proteins by nerves from controls and diabetic rats.Nerves undergoing Wallerian degeneration showed a marked increase in DNA content and stimulated incorporation of [14C]leucine into proteins. 14CO2 production from leucine proceeded at 75% of the rate observed in intact nerves. Neither insulin nor diabetes affected leucine metabolism in degenerating nerves.Neither the extracellular space nor the concentration of free amino acids were significantly different in nerves obtained from control and diabetic rats, except for lower glutamine content in the latter. In vitro leucine metabolism of nerves is affected by diabetes, insulin and the integrity of the axon. The Schwann cell is suggested as a possible site of the observed changes in leucine metabolism.
PYRUVATE KINASE ISOZYMES IN NEURONS, GLIA, NEUROBLASTOMA, AND GLIOBLASTOMA
Authors: Tolle Susan Willis , Dyson R. D. , Newburgh R. W. , Cardenas Janet M. 
Published: October 2006

Abstract– The distribution of pyruvate kinase isozymes (EC 2.7.1.40) was examined in cells and tissues from the central and peripheral nervous system of the rat. Most tissues contain significant quantities of both the K4 (fetal type) and M4 (skeletal muscle type) isozymes plus tetrameric hybrids comprised of various combination of the type M and type K subunits. Retina, for example, contains a five‐mem‐bered hybrid set weighted toward K4, while sciatic nerve and spinal cord have patterns very similar to that of adult brain, consisting predominantly of M4 with small amounts of K4 and K‐M hybrids. This adult pattern is achieved by a gradual shift from a hybrid set dominated by K4 in fetal life, to the pattern at birth at which time the two most prominent bands were M4 and K2M2, and finally to the adult pattern by about 28 days after birth.Neurons and glial cells were isolated from rat and mouse brains at the various developmental levels. The pyruvate kinase isozyme patterns in the two cell types were similar to each other and to the patterns seen in whole brain homogenates at all ages, indicating similar rates of isozymic maturation in the two cell types.The correlation of maturation with pyruvate kinase isozyme patterns was further tested in cultures of malignant cell lines. A K‐M hybrid set, weighted toward K4, was seen in two clonal lines of mouse neuroblastoma under normal culture conditions. However, lowering the serum concentration in the culture medium or adding bromodeoxyuridine caused a shift in the patterns toward type M as the cells differentiated, mimicking in part the in vivo maturation of normal cells. On the other hand, a rapidly growing and poorly differentiated line of rat glioblastoma had only K4 under all conditions examined.
THE INFLUENCE OF PRENATAL X‐IRRADIATION ON THE ACTIVITY OF sRNA‐AMTNOACYL SYNTHETASES IN THE DEVELOPING RABBIT BRAIN
Authors: Wender M. , Zgorzalewicz B. 
Published: October 2006

Abstract—The activities of sRNA‐aminoacyl synthetases (EC 6.1.1) were investigated in the cerebral white and grey matter of rabbits subjected during their prenatal life to a single X‐ray dose of 150 rad. The results of investigations have shown that ionizing radiation acting during intrauterine development of the experimental animal brings about a distinct depression of all sRNA‐aminoacyl synthetase activities in the newborn irradiated litter. During the postnatal development of these animals the activities of some of the synthetases further decreased and even at adulthood, where they are normally very low, their activities were below the control values. The activities of some other synthetases, after the initial depression, showed no further decrease and at adulthood had values comparable to controls. Our results indicate clearly that prenatal exposure to ionizing radiation also affects the step of protein biosynthesis which depends on the activity of sRNA‐aminoacyl synthetases.
CELLS ISOLATED FROM TRYPSIN‐TREATED BRAIN CONTAIN TRYPSIN
Authors: Guarnieri M. , Cohen S. R. , Ginns E. 
Published: October 2006

Abstract—Neuronal and oligodendroglial cell fractions isolated from trypsinized brain contain trypsin. Neuronal cell bodies contained approximately 5 μg of trypsin/mg of cell protein; oligodendroglial cells had approx 1 μg of enzyme activity. Studies with fluorescein‐conjugated trypsin suggested that least a portion of the fluorescent enzyme was internalized in neurons.
SYNTHESIS AND DEGRADATION OF PROTEIN OF VISUAL RECEPTOR MEMBRANES IN LATERAL EYES OF LIMULUS1
Authors: Krauhs J. M. , Mahler H. R. , Minkler G. , Moore W. J. 
Published: October 2006

Abstract—The spatial and temporal distribution of labelled protein in lateral eyes of Limulus polyphemus has been followed after injection of l‐[3H]leucine into the pericardial sinus. Labelled protein in the eyes rises for 3 h, for the first hour more rapidly in the cytoplasm but thereafter preferentially in the rhabdomal membranes of the visual receptor cells. In light, the label in the membrane reaches a peak at 3 h whereas in dark the peak is at 6 h. The subsequent decrease in label in light has a half life of about 2 h, but in dark is biphasic with halflives of 2 h and 8 days. These results can be interpreted on the basis that the major labelled protein in the rhabdomal membrane is rhodopsin, the degradation rate of which is enhanced when the membranes are depolarized by light.
SUB‐CELLULAR LOCALISATION OF ENHANCED LYSINE INCORPORATION INTO CEREBRAL CORTEX PROTEINS IN DARK‐REARED AND LIGHT‐EXPOSED RATS
Authors: Jones‐Lecointe Altheia , Rose S. P. R. , Sinha A. K. 
Published: October 2006

Abstract—Incorporation of lysine into acid‐insoluble material from subcellular fractions of rat cerebral cortex has been studied using double and single‐labelling techniques, in littermates reared for 50 days in the dark and then dark‐maintained or light‐exposed for 1 h. When light‐exposed animals were compared to dark controls the only subcellular fraction from the whole cortex in which lysine incorporation shows a significant elevation (168%, P < 0.05) was located in the ribosomal pellet of the cerebral cortex. A similar comparison of subcellular fractions from visual and motor cortices showed that the elevation was again in the ribosomes and confined to visual cortex only. Motor cortex of light‐exposed animals showed a small depression of incorporation in ribosomes as compared to dark controls. Sub‐fractionation of nuclei from whole cortex preparations showed varying, but non‐significant elevations in light‐exposed animals in all but the histone fraction in which there was negligible incorporation of precursor. It is concluded that enhancement of incorporation of precursor into proteins of the cerebral cortex, which accompanies first exposure to light, is a complex response. At exposure for 1 h it involves a number of particular protein species located in the visual cortex, a major proportion of which are ribosomally bound.
A STUDY OF THE MOLECULAR SIZES AND STABILITY OF CHOLINE ACETY LTRANSFER ASE
Authors: Banns Heather E. 
Published: October 2006

Abstract—Aggregation of the enzyme acetyl‐CoA: choline‐O‐acetyltransferase (ChAc, EC 2.3.1.6) which appears to be homogeneous has been observed. The molecular weight of the most abundant form of ChAc was estimated by gel filtration and sucrose gradient centrifugation to be in the range 58,000‐62,000. The most frequently encountered aggregates were much larger and eluted in the void volume from Sephadcx® G‐100 and G‐150 indicating molecular weights in excess of 400,000. In fact, they were subsequently found to be 1.2 × 106 and 1.9 × 106 by sucrose gradient centrifugation. The percentage of activity associated with high molecular weight ChAc increased with purification, but these aggregates disappeared after storage for 2‐3 weeks at −20°C. The loss occurred independently of any fall in enzymic activity in the preparations examined.
SITE OF BIOSYNTHESIS OF BRAIN‐SPECIFIC PROTEINS IN THE GIANT FIBRE SYSTEM OF THE SQUID
Authors: Alemà S. , Giuditta A. 
Published: October 2006

Abstract—The synthesis of brain‐specific proteins has been examined in perikaryal and axonal regions of the giant fibre system of the squid. After in vitro incubation of stellate ganglia, stellate nerves and isolated giant axons with radioactive amino acids, the labelled soluble proteins have been extracted from the giant fibre lobe, the axoplasm and the axonal sheath of the giant axon and have been separated by gel electrophoresis on a continuous system. In addition, they have been challenged with antisera prepared against the cephalopod brain‐specific proteins L1 and L2 and the resulting precipitate has been resolved by sodium dodecyl sulphate‐gel electrophoresis. Synthesis of these two proteins appears to be restricted to the giant fibre lobe, while an additional discrete protein band (L5) also becomes clearly labelled in the isolated giant axon. Radioactive components migrating in the region of the L1 and L2 proteins are synthesized in the isolated giant axon. They can be distinguished from tbese proteins on the basis of electrophoretic and immunochemical criteria.
THE ACETYLCHOLINESTERASE AND PSEUDO‐ CHOLINESTERASE CONTENTS OF HUMAN PLACENTA AT TERM
Authors: Ruch G. A. , Davis R. , Koelle G. B. 
Published: October 2006

AbstractThe acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities of human term placentas have been studied. Perfusion of placentas indicated that most of the AChE and all the BuChE content of the human placenta are due to its blood content. By comparison, rabbit livers, studied similarly, retained most of their contents of both enzymes following perfusion. Histochemical examination or well‐perfused placentas suggests that trapped intact erythrocytes and the stroma of hemolyzed red cells are the probable source of ‘placental’ AChE reported previously.