Ukrains'kyi biokhimichnyi zhurnal最新文献

Benzole vapours cause a decrease in the content of glutamic acid in the motor cortex, cerebellum, pons varolii and spinal cord of the rat brain at different stages of ontogeny. The content of GABA increases in all the areas during ontogeny with benzole intoxication. The glutamate decarboxylase activity increasing in all brain areas in different periods of postnatal development rises after the benzole action. The activity of GABA transamination enzyme in the brain motor cortex under the benzole effect is not changed in newborns and three-month rats, in 10- and 21-days rats it decreases, in 12- and 24-months animals it increases. In the cerebellum, pons varolii and spinal cord the activity of this enzyme rises in newborns, three- 12- and 24-months rats and lowers in 10- and 21-day ones. The rise in the level of GABA and activity of the enzymes of its metabolism in the different brain areas under the benzole effect is considered as an adaptation reaction of the nerve cells.

The activity of the mitochondria internal membrane ensymes alpha-ketoglutarate dehydrogenase and succinate dehydrogenase was studied after rats poisoning with CCl4. It is established that the activity of these enzymes lowers considerably under effect of CCl4, which is more pronounced for alpha-ketoglutarate dehydrogenase. The pretreatment of animals with inducer of microsomal oxidases intensifies the damaging effect of CCl4 on the internal membranes of mitochondria and decreases the LD50 value for CCL4. Administration of actinomycin D simultaneously with polycyclic hydrocarbons prevents intensification of the CCl4 hepatotoxic effect caused by 3-methylcholanthrene and dibenz (a, h) anthracene.

Administration of estradiol-benzoate in a dose of 0.5 Mg for 4 days causes a twice increase in the content of acetylcholine in hypothalamus of impuberal female rats and statistically significant decrease in the content of GABA. The level of serotonin, dopamine, noradrenaline and histamine in the hypothalamus of the animals is not affected by 0.5 Mg of estradiol-benzoate. Administration of prolactin against a background of estradiol--benzoate normalizes the content of GABA and produces a statistically significantly drop in the level of acetylcholine in the hypothalamus. A conclusion is drawn that acetylcholine and GABA are involved into regulation of prolactin secretion in rats.

The IR-spectra of normal and deuterated gelatin samples were studied. The 3300 cm-1 band is determined by the valence vibrations of the peptid bond NH-groups, OH-groups of oxyproline and structural water. The 1280-1220 cm-1 bands cannot be intepreted for gelatin as amide III; their appearance is caused by the skeleton vibrations. The 1460 cm-1 band is not Amide II in gelatin, it is associated with the deformation vibrations in free methyl groups of the amino acid residues. The effect of OH-groups of hydration water forming the intramolecular hydrogen bond is displayed by 1670 cm-1 band. Disappearance of the 1560 and 1530 cm-1 bands with deuterating and appearance of the 1580 cm-1 band may evidence for a structural transition of the gelatin molecule from one conformation to another, is more ordered, conformation.

Sorption properties of sarcolemma preparations isolated from skeletal muscles of normal and E-avitaminous rabbits were studied relative to organic ions. Analysis of isotherms of sarcolemma equilibrium binding of neutral red cations and turquoise direct lightfast "K" anions made it possible to determine the number of positively and negetively charged sorption centres, which fix the mentioned dyes. With E-avitaminous muscular dystrophy the number of the centres increases considerably. A larger number of the positively charged centres fixing the surquoise dye are found both in the control and in case of dystrophy. The calcium ions prevent the neutral red sorption and intensify the turquoise direct sorption. In the sarcolemma preparations isolated from the muscles of the E-avitaminous rabbits the content of calcium ions is almost twice as high and the number of sulphydryl groups is 30-40% less as compare to the normal level. The data presented evidence for structural changes in sarcolemma with E-avitaminous muscular dystrophy.

A method is developed for the quantitative determination of the protector activity. The method is based on registrating the coagulation time shortening for a mixture of fibrin monomer and fragment D. All determinations should be carried out at high concentrations of fragment D when its inhibitory effect on fibrin polymerization is very strong. It is necessary to control the exact conditions as to ionic strength and pH of the reaction mixture. Another approach to the protector activity estimation is demonstrated. It is based on determination of clot protein quantities after fibrin monomer clotting in mixtures with constant fragment D and different protector quantities.

Oxygen and water are inhibitors of acyloin and benzoin condensations. An intermediate paramagnetic compund is formed in the benzoin condensation catalyzed with 3-benzyl-4-methyl thiazolium chloride, 3,4-dimethyl thiazolium iodide, 3-benzyl-4,5-dimethyl thiazolium chloride, 3-methyl-4-phenyl thiazolium perchlorate and 3-methyl-4,5-diphenyl thiazolium perchlorate. The formation of benzoin in dimethyl sulphoxide, when the air oxygen is absent, is an irreversible reaction. The presence of hydrophobic solvent in the reaction medium provides more favourable conditions for benzoin condensation proceeding. The reaction mechanism is suggested.

Subcellular fractions of the cerebral hemispheres of rabbits of different age groups are isolated by differential centrifugation in the sucrose gradient. The acetylcholinesterase activity of the fractions is also determined. It is found that in the postnatal period the specific activity of the enzyme increases in synaptosomes and pure mitochondria, is unchanged in the initial homogenate and in the subfraction of mieline fragments. The relative specific activity of acetylcholinesterase is unchanged in mitochondria, increases sharply in synamptosomes and decreases in the subfraction of myeline fragments. Changes in the specific and relative specific activity of acetylcholinesterase in the subcellular fractions of the developing brain are concluded to reflect the degree of functional maturation of cholinergic structures responsible for conducting the nervous impulse.

The content of vitamin C in tissues was determined for animals synthetizing (rabbits) and nonsynthetizing (guinea pigs) it with UV radiation. Significant doses of radiation cause a considerable decrease in the content of vitamin C in blood of both animal species. In the adrenal, liver, spleen, lung, small intestine, kidney, brain tissues and vitamin C content decreases in animals nonsynthetizing the vitamin and, vice versa, it rises in the vitamin-synthetizing animals. After irradiation with small doses the vitamin C content in blood and tissues of animals nonsynthetizing it lowers but not below the normal level. Additional administration of 100 mg of ascorbic acid (under conditions of sufficient supply of vitamin C with food) does not prevent a decrease in the content of vitamin C in blood of the animals irradiated with significant UV doses. An opinion is advanced as to necessity of vitamin C rationing taking into account "the UV climate" of the area and dose of radiation from the artifical sources.

Intensity of glycolysis was studied under conditions of immobilization stress and adrenalectomy as well as with administration of adrenaline and hydrocortisone. The processes of aerobic glycolysis, activity of enzymes of the tricarboxylic acid cycle and mitochondria respiratory chain, content of total, free and protein-bound glycogen, glucose-I-phosphate, glucose-6-phosphate, pyruvate, alpha-ketoglutarate, cytrate and macroergs in the brain are shown to depend on the level of adrenal hormones producing a multilateral effect on a series of energy metabolism links.