[On vitamin B1 metabolism in avitaminosis and its correction with thiamine and taurine]. / K voprosu metabolizma vitamina B1 v usloviiakh avitaminoza i ego korrektsii tiaminom i taurinom.

The levels of phosphate esters and the activities of thiamine biotransformation enzymes in the blood and tissues of albino rats were studied during oxythiamine-induced B1 deficiency and after metabolic correction with thiamine and taurine. Among thiamine phosphates, the most informative indicators of thiamine deficiency were shown to be triphosphate esters and free thiamine diphosphate. The biosynthetic enzymes thiamine kinase and thiamine diphosphate kinase played a decisive role in maintaining the initial rate and in recovering the physiologically active forms of vitamin B1. The activation of hydrolytic enzymes of thiamine phosphate esters occurred by producing abundant free thiamine diphosphate and thiamine triphosphate. Within the first hours, taurine favoured the acceleration of phosphoester biosynthesis and, accumulating in the tissues, inhibited vitamin phosphorylation reactions.

[Metabolism of vitamin B1 and its di- and triphosphate esters in experimental allergic encephalomyelitis]. / Metabolizm vitamina B1 i ego di- i trifosfornogo efirov pri éksperimental'nom allergicheskom éntsefalomielite.

Biological significance of thiamin in development of experimental allergic encephalomyelitis has been elucidated. It has been shown that at the late preclinical stage of the disease thiamine metabolism is predominantly directed towards the maintaining of cellular metabolic homeostasis, whereas at the stage of clinical symptoms the anabolic process gives way to catabolic decomposition. Among tested thiamine phosphates the triphosphate ester is the most informative parameter in demyelinizing processes. Thiamine injections to immunized animals accelerate the vitamin phosphorylation depleting the reducing and energy potentials of the cell. Such thiamine antagonist as oxythiamine inhibits phosphatase reactions.

[Metabolism of vitamins B1 and PP and their use in oncological practice]. / Obmen vitaminov B1 i PP i ikh primenenie v onkologicheskoi praktike.

Blood of patients with gastric tumor was studied after their admission to the hospital and after the chemotherapeutic course. Formation of the tumor was accompanied by development of hypovitaminoses B1 and PP. The vitamin deficiency was more distinct after treatment of the patients with cyclophosphan: content of thiamine diphosphate (TDP) was decreased by 40%; NAD+NADP, by 30% and NADH+NADPH, by 20%. In mice with Ehrlich ascites carcinoma, activity of transketolase in erythrocytes was decreased by 48%, content of TDP, by 61% and that of NADPH, by 27%. The administration of cyclophosphan increased further thiamine deficiency in the tumor-bearing mice. Simultaneous administration of thiamine and cyclophosphan abolished the cytostatic toxic effect but did not affect their antitumoral properties. Under these conditions treatment with vitamins B1 and PP complex was undesirable due to malignization. The vitamins B1 and PP did not stimulate the tumor growth, partially restored impaired metabolism of the vitamins and may be included separately into combined multidrug oncotherapeutics.

[Fermentation micromethod for the quantitative determination of thiamine diphosphate in biological fluids]. / Fermentativnyi mikrometod kolichestvennogo opredeleniia tiamindifosfata v viologicheskikh zhidkostiakh.

An enzymatic micromethod is proposed for quantification of thiamine biphosphate (TBP) at concentrations from 0.5 ng in 0.1-0.2 ml samples of blood or other biological liquids. The dynamics of TBP degradation in blood was studied depending on the time and conditions of storage. A high efficient complex of alcohol dehydrogenase and apopyruvate decarboxylase was isolated from baker's yeasts that can be successfully used for quantitative detection of TBP. The complex was stabilized for further application to biochemical kits for diagnosis of B1-deficiency.

[Metabolism of thiamine and its di- and triphosphorus esters in the blood of patients with neurological symptoms of osteochondrosis]. / Metabolizm tiamina, ego di- i tri-fosfornogo éfirov v krovi bol'nykh s nevrologicheskimi proiavleniiami osteokhondroza.

Concentrations of phosphate esters in blood of patients with vertebral osteochondrosis and activities of enzymes involved in thiamine metabolism have been investigated. The pathological processes were characterized by a decrease in content of thiamine triphosphate while concentration of coenzyme, thiamine diphosphate, was relatively constant. The enzymes involved in the initial and final steps of biosynthesis and degradation of thiamine phosphorylated derivatives play the main role in maintaining vitamin B1 metabolic homeostasis.

[Thiamine triphosphate content of the liver of albino rats with different levels of thiamine]. / Soderzhanie tiamintrifosfata v pecheni belykh krys pri pazlichnoi obespechennosti tiaminom.

Content of thiamine triphosphate (TTP) was studied in rat liver tissue under conditions of normal state, thiamine deficiency and after loading with thiamine. The concentration of TTP in hepatocytes of control animals was found to be 3.2-3.6 micrograms/g, corresponding to 40% of the total thiamine pool in the cells. The TTP appears to serve as a reserve of vitamin B1 deposited in mitochondria of the cells in which the biosynthesis of thiamine pyrophosphate of their own did not take place. Administration of thiamine did not induce the TTP overproduction in hepatocytes; the content of TTP was maintained in the mitochondria of the hepatocytes at the constant level.

[Nature of the bond between the coenzyme and protein in pig liver transketolase]. / O prirode sviazi mezhdu kofermentom i belkom v transketolaze iz pecheni svin'i.

It was shown that the bond between the coenzyme and protein in pig liver transketolase is not covalent as was reported previously. Boiling of the enzyme preparation for 2 min or treatment with 10% trichloracetic acid results in a complete split-off of thiamine pyrophosphate.

[Content of free and bound thiamine diphosphate in the liver hyaloplasm of vitamine B1 deficient rats]. / Soderzhanie svobodnogo i sviazannogo tiamindifosfata v gialoplazme pecheni krys pri razlichnykh B1-avitaminoziykh sostoianiiakh.

The amount of free and protein-bound thiamin diphosphate (TDP) in the liver hyaloplasm of B1 vitamin deficient rats has been measured. In the norm the content of protein-bound TDP remains stable (4.5--4.7 micrograms/g tissue) and does not grow upon thiamin injections. The level of the free coenzyme varies appreciably: in the B1-avitaminotic state the content of free TDP decreases, and in the B1-saturated condition it may exceed the norm 4 times. In the liver this enzyme occurs only as a holoenzyme. In case of B1 vitamin deficiency in the diet the transketolase apoform cannot be detected in the liver. A new model for rapid generation of B1-avitaminosis characterized by a significantly lower level of free and bound TDP is described.

[Changes in the activity of alkaline phosphatase and the level of thiamine diphosphatase in simulations of B1 avitaminosis]. / Izmenenie aktivnosti shchelochnoi fosfatazy i soderzhaniia tiamindifosfata pri modelirovanii avitaminoza B1

Alimentary B1 avitaminosis was attended by a declining activity of alkaline phosphatase in the brain and spleen of rats. A single administration of oxythiamine to rats in a dose of 400 mg/kg produced during the first hours an increased activity of alkaline phosphatase in the liver, brain and, to a lesser extent, in a number of other organs and reduced the thiamine-diphosphate content in the liver, brain and other tissues. The thiamin-diphosphate level in the brain returned back to normal in 12 hours, and in other tissues-towards the 3--5th day. In 24 hours after introduction of oxythiamine the activity of alkaline phosphatase was up in the liver alone, while in the brain the activity of the enzyme decreased. Thiamine, used in a dose of 400 mg/kg, exerted on the activity of alkaline phosphatase in a number of tissues an action similar to that of oxythiamine. It is suggested that the activation of alkaline phosphatase 3--12 hours following adminstration of a large dose of thiamine or oxythiamine is of a non-specific nature. Subcutaneous introduction of a commercial alkaline phosphatase preparation to rats brought down the thiamine-diphosphate level in all of the tissues under investigation. The presumed mechanisms accounting for the fall of thiamine-diphosphate and the possible part played in this process by alkaline phosphatase are discussed.