journal article
LitStream Collection
Home
Wood, J. D.; Watson, W. J.; Murray, G. W.
doi: 10.1111/j.1471-4159.1969.tb10366.xpmid: 5795581
Abstract— The susceptibility of mice to seizures at hyperbaric pressures of oxygen (OHP) was placed on a quantitative basis and compared with the corresponding rate of decrease in brain GABA concentration. The influence of small amounts of carbon dioxide in the breathing mixture on these effects of OHP was also determined. A correlation between the rate of decrease in GABA and susceptibility to seizures was shown to exist not only over the varying oxygen pressures and varying concentrations of carbon dioxide used in the present experiments out also over varying animal species (a previous study). The critical oxygen pressure for decreases in brain GABA to occur was shown to be 30 p.s.i.g. This value agreed closely with the well documented critical pressure necessary to produce seizures in both animals and man. The probability that lowered brain GABA levels play a major role in the etiology of OHP convulsions was discussed.
Woodward, J. K.; Bianchi, C. P.; Erulkar, S. D.
doi: 10.1111/j.1471-4159.1969.tb10367.xpmid: 5795582
Abstract— Superior cervical ganglia of the rabbit were removed and analysed for Na+, K+, Ca2+, Mg2+ and Cl−. The mean electrolyte content in μmole/g wet wt. was as follows: Na+, 64.7 ± 1.3; K+, 65.1 ± 2.7; Ca2+, 3.71 ± 0.28; Mg2+, 3.70 ± 0.50; and Cl−, 50.15 ± 2.26. Water content was 0.76 ± 0.01 ml/g wet wt. Extracellular space was 0.37 ± 0.01 ml/g, and the vascular space 0.0238 ± 0.0002. The mean resting potential of the rabbit superior cervical ganglion was – 68.6 mv. After correction for extracellular electrolyte content, the potential differences, ENa, EK and Ecl, were estimated to be +33.6 mv, –96.9 mv and ‐41.1 mv, respectively, in the ganglia. Permeability coefficients for K+, Na+, and Cl− were estimated to be 1:0.06:0.02. Replacement of sodium in physiological saline solution by lithium results in a displacement of 94 per cent of the sodium content of the ganglion and 69 per cent of the potassium after 30 min of equilibration.
Pascal, Theresa A.; Saifer, A.
doi: 10.1111/j.1471-4159.1969.tb10368.xpmid: 4978610
Abstract— Gangliosides G1 to G5 were isolated from human brain by means of TLC and tested with respect to their specificity to antisera against normal brain and Tay‐Sachs brain gangliosides by agar double diffusion analysis. Gangliosides G2 and G4 gave precipitation reactions with antisera to normal human gangliosides (NHG) while only ganglioside G6 reacted with antisera to Tay‐Sachs gangliosides (TSG). Additional specificity information was also obtained by use of the enzyme neuraminidase for the removal of specific sialic acid (NANA) residues. It was concluded from these data that the specificity of the anti‐NHG antibodies is determined by the presence of a galactose (β1, 3) N‐acetyl galactos‐amine–while that of anti‐TSG antibodies is due to a N‐acetyl galactosamine (β1, 4) galactose‐end sequence. By means of natural compounds of known structure it was found that both the sequence of carbohydrate residues and position of NANA residues in the molecule played a critical role in the formation of precipitation bands with NHG‐antisera. This information was utilized to distinguish one isomeric form of disialoganglioside from another, i.e. G2 from G3 and to confirm the structure of the trisialoganglioside, G1. The immunochemical method appears to be a useful one for elucidating structural differences in ganglioside molecules.
Caldarera, C. M.; Moruzzi, M. S.; Rossoni, C.; Barbiroli, B.
doi: 10.1111/j.1471-4159.1969.tb10369.xpmid: 5795583
Abstract— Spermine and spermidine reach maximum concentrations in the chick embryo brain between the 12th and 14th day of incubation. Sucrose‐density‐gradient analysis of polyribosome distribution in the developing chick embryo brain, showed the presence of polyribosomal aggregates in the regions of 147 S and 206 S between the sixth and eighth day of incubation. After the 16th day of incubation the presence of heavier polyribosomal aggregates in the region of 259 S and 280 S was found. The injection of spermine or spermidine into the air space of embryos on the tenth day of incubation leads to a remarkable increase in the incorporation rate of (3H)formate into the ribosomes. Studies under similar experimental conditions, showed an increased radioactivity in the region of 147 S, 206 S, 259 S and 280 S in embryos injected with spermine or spermidine.
doi: 10.1111/j.1471-4159.1969.tb10370.xpmid: 5795584
Zusammenfassung— Die Aktivität der Glutaminase und Glutaminsynthetase sowie die Konzentration des freien Ammoniaks werden im Gehirn von Ratten während und vor cerebralen Anfällen bestimmt. Mit Einsetzen des Krampfes, nach i.e. Injektion von Pyridoxal‐5‐phosphat bereits in der Phase der sham rage, steigt die Aktivität der Glutaminase stark an. Der hierdurch bedingte erhöhte Substratumsatz führt zur Anhäufung von freier Glutaminsäure und Ammoniak im Hirngewebe. Diese Stoffwechselentgleisung ist möglicherweise eine weitere Ursache für das Entstehen cerebraler Anfälle. Die Glutaminsynthetase ist am Zustandekommen der von uns untersuchten experimentellen Krampfanfälle nicht merklich beteiligt. Die Konzentration des Ammoniaks ist sowohl in der präkonvulsiven als auch in der tonischen Phase des Krampfanfalls erhöht. Die beobachteten Veränderungen werden übereinstimmend mit anderen Autoren als Folge eines veränderten Stoffwechsels im erregten Nervengewebe angesehen, jedoch nicht als spezifisches oder auslösendes Merkmal cerebraler Anfälle.
doi: 10.1111/j.1471-4159.1969.tb10371.xpmid: 5795585
Abstract— 1 After intraperitoneal injection, there is negligible incorporation of (2‐14C)‐mevalonic lactone into the CNS of the adult rat. 2 Mevalonic lactone injected into the CSF is quickly transferred to blood. 3 Mevalonic lactone injected in the cistema magna or the lateral ventricle of the brain does not diffuse readily into the whole CSF. Spinal cord cholesterol is most heavily labelled after intracisternal injection, as is brain cholesterol after intraventricular administration. 4 After intraventricular perfusion, the diffusion of mevalonic lactone into the ventricle opposite the side of the injection is increased when the rate of perfusion is doubled from 5 to 10 μ1/hr. After injection, optimal homogeneity is obtained if a large volume (70μl) is administered. 5 An increase in the volume of injection from 70 μl to 130μl does not alter the distribution of activity between the left and right ventricles, nor does it increase the diffusion of mevalonic lactone from ventricle to spinal cord CSF. 6 The mean yield of mevalonic lactone incorporation into brain cholesterol is much higher after injection than after perfusion of precursor into the lateral cerebral ventricle.
Martenson, R. E.; Gaitonde, M. K.
doi: 10.1111/j.1471-4159.1969.tb10372.xpmid: 5795586
Abstract— A purified basic protein fraction of adult rat brain when injected into guinea pigs induced experimental allergic encephalomyelitis (EAE). The freeze‐dried preparations were subjected to electrophoresis on 5% polyacrylamide gel at pH 10.6 in the presence of 8 m‐urea to obtain one‐step separation of highly basic proteins from other proteins. Under these conditions the highly basic proteins whose isoelectric point exceeded pH 10.0 gave seven distinct components. After staining these protein bands with naphthalene black 10B they were scanned densitometrically: the area under each peak was computed and used for calculation of the amounts of individual basic proteins. The acid extracts of rat brain contained 2.61–3.95 mg highly basic proteins/g fresh tissue. A comparison of the electrophoretic patterns of acid extracts of rat brain and liver showed that two of the highly basic proteins (components 1 and 2) were present only in the brain and not in the liver. These two components in the brain were attributed to proteins of the myelin sheath.
doi: 10.1111/j.1471-4159.1969.tb10373.xpmid: 5795587
Abstract— The staining pattern of acid ribonuclease activity in the nervous tissues of rats has been studied with different fixatives and incubation media. Certain modifications in the method adopted (Vorbrodt, 1961) produced a definite improvement in the localization as well as distinct subcellular distribution at the pHs studied. The modifications introduced consisted of preincubation of tissue sections with prostatic acid phosphatase, omission of acid phosphatase from the standard incubation medium and its addition at a later stage of incubation. This avoids much of the diffused cytoplasmic and filamentous background staining at pH 5.2–5.8, eliminates the irregular nuclear staining at pH 4.5 and replaces the strong nuclear positivity at pH 5.2 by a fine granular dispersion. A study of the enzyme activity of subcellular fractions at the different pHs used was performed to confirm the histochemical localization.
Marchi, Wilhelmina J.; Johnston, G. A. R.
doi: 10.1111/j.1471-4159.1969.tb10374.xpmid: 4389537
Abstract— Glycine was a substrate for d‐amino acid oxidase purified from extracts of cat spinal cord and sheep cerebellum. d‐Aspartate and N‐methyl‐d‐aspartate were oxidized at a rate similar to that of glycine by the purified sheep cerebellum extract; d‐α‐alanine and d‐serine were oxidized appreciably faster than glycine, while GABA and d‐glutamate were not oxidized at a measurable rate. p‐Mercuribenzoate and kojate inhibited the oxidation of glycine by the purified sheep cerebellum extract. d‐Amino acid oxidase activity was higher in the grey than in the white matter of cat spinal cord, while the reverse was true for the cerebral cortex; the activity in the cord and cerebral cortex was much lower than that in the cerebellum.
Showing 1 to 10 of 25 Articles