Thiazolium salt mimics the non-coenzyme effects of vitamin B1 in rat synaptosomes.

Long-term studies have confirmed a causal relationship between the development of neurodegenerative processes and vitamin B1 (thiamine) deficiency. However, the biochemical mechanisms underlying the high neurotropic activity of thiamine are not fully understood. At the same time, there is increasing evidence that vitamin B1, in addition to its coenzyme functions, may have non-coenzyme activities that are particularly important for neurons. To elucidate which effects of vitamin B1 in neurons are due to its coenzyme function and which are due to its non-coenzyme activity, we conducted a comparative study of the effects of thiamine and its derivative, 3-decyloxycarbonylmethyl-5-(2-hydroxyethyl)-4-methyl-1,3-thiazolium chloride (DMHT), on selected processes in synaptosomes. The ability of DMHT to effectively compete with thiamine for binding to thiamine-binding sites on the plasma membrane of synaptosomes and to participate as a substrate in the thiamine pyrophosphokinase reaction was demonstrated. In experiments with rat brain synaptosomes, unidirectional effects of DMHT and thiamine on the activity of the pyruvate dehydrogenase complex (PDC) and on the incorporation of radiolabeled [2-14C]pyruvate into acetylcholine were demonstrated. The observed effects of thiamine and DMHT on the modulation of acetylcholine synthesis can be explained by suggesting that both compounds, which interact in cells with enzymes of thiamine metabolism, are phosphorylated and exert an inhibitory/activating effect (concentration-dependent) on PDC activity by affecting the regulatory enzymes of the complex. Such effects were not observed in the presence of structural analogs of thiamine and DMHT without a 2-hydroxyethyl substituent at position 5 of the thiazolium cycle. The effect of DMHT on the plasma membrane Ca-ATPase was similar to that of thiamine. At the same time, DMHT showed high cytostatic activity against neuroblastoma cells.

Thiamine deficiency in rats affects thiamine metabolism possibly through the formation of oxidized thiamine pyrophosphate.

BACKGROUND: Thiamine deficiency (TD) has a number of features in common with the neurodegenerative diseases development and close relationship between TD and oxidative stress (OS) has been repeatedly reported in the literature. The aim of this study is to understand how alimentary TD, accompanied by OS, affects the expression and level of two thiamine metabolism proteins in rat brain, namely, thiamine transporter 1 (THTR1) and thiamine pyrophosphokinase (TPK1), and what factors are responsible for the observed changes. METHODS: The effects of OS caused by TD on the THTR1and TPK1 expression in rat cortex, cerebellum and hippocampus were examined. The levels of active and oxidized forms of ThDP (enzymatically measured) in the blood and brain, ROS and SH-groups in the brain were also analyzed. RESULTS: TD increased the expression of THTR1 and protein level in all studied regions. In contrast, expression of TPK1 was depressed. TD-induced OS led to the accumulation of ThDP oxidized inactive form (ThDPox) in the blood and brain. In vitro reduction of ThDPox by dithiothreitol regenerates active ThDP suggesting that ThDPox is in disulfide form. A single high-dose thiamine administration to TD animals had no effect on THTR1 expression, partly raised TPK1 mRNA and protein levels, but is unable to normalize TPK1 enzyme activity. Brain and blood ThDP levels were increased in these conditions, but ThDPox was not decreased. GENERAL SIGNIFICANCE: It is likely, that the accumulation of ThDPox in tissue could be seen as a potential marker of neurocellular dysfunction and thiamine metabolic state.

PROTOCOL NUTRITION THERAPY OF CRITICALLY ILL CHILDREN.

The Protocol isn't seen as directive. The goal of the Protocol is to define theframes ofdiagnostic criteria and therapeutic action, within which a doctor working in an intensive therapy children have freedom of choice. The Protocol takes into account that the critical and postagressive states are characterized by the features of malnutrition, particularly manifested in the period of intensive growth (first life year). The Protocol submitted by: contraindications to artificial nutricion in any form; indications for parenteral nutrition; components ofparenteral nutrition; calculation of water and energy needs; calculation of substrate requirements; the system of "two in one" and "three in one "; monitoring the effectiveness ofparenteral nutrition; the use of adjuvants and active additives to artificial nutrition, indications for early enteral nutrition, time of the beginning of enteral nutricion and tolerance to it: trial feeding; trophic nutricion; the technique ofprobe feeding; selection offormulas for enteral nutrition; monitoring the effectiveness of enteral nutrition. The Protocol does not discuss the issues of planned nutritional preparation for surgery, nutritional support in chronic malabsorption, sipping.

[MONITORING OF HEMODYNAMICS IN THE CHOICE OF INTENSIVE THERAPY IN THE OPERATED INFANTS].

Noninvasive monitoring in obtaining important and reliable information relevant to pediatric practices, not only in respect of dangers and complications of most invasive techniques, but also because a number of them difficult or even impossible in infants. The aim of this study was to estimate the significance of hemodynamic parameters and capabilities of ECHO and dophlercardiography for analyzing violations hemodynamics in primary diagnosis and conduct drug therapy in infants. The study included the results of a survey of 65 infants aged from 29 to 39 weeks with various surgical pathology, who received the various options the hemodynamic support. In the initial assessment and selecting tactics of therapy for hemodynamic analysis carried out routine monitoring and for evaluation of cardiac contractility used echo- and Doppler exams. All children have pointed out a number of significant changes of haemodynamics, that has required inotropic therapy with dopamine (64% of children with diaphragmatic hernia received additional dobutamine). Validation of expressed pulmonary hypertension children appointed sildenafil, and in the absence ofthe effect used nitrous oxide. Hemodynamic monitoring allows to monitor the status of circulation on the background of the treatment and to make timely changes to the script therapy.

[EPIDURAL ANALGESIA FOR INTRAOPERATIVE AND POSTOPERATIVE CARE IN NEWBORNS].

Anesthesia care in newborns has to be complex, balanced and safe. Nowadays epidural analgesia (EA) in neonates during intra- and postoperative period is widely used in Russia. Modern EA techniques imply the installation of a catheter into epidural space at lumbar or thoracic level as well as different approach to local anesthetics dosage. Newborns have special anatomy, physiology and pharmacodynamics which have to be taken in mind when EA is used. At the present moment Ropivacine (2 mg/ml) is approved for peripheral nerve blocks in newborns.

[Modern approach to the neuromuscular blocking agents use in pediatric patients].

Myorelaxants use decrease trend appeared since the end of 80 years of the 20th century. The trend is connected with use of the new narcotic analgesics (Remifentanil), intravenous (Propofol) and inhalation (Sevoflurane) anaesthetics. These drugs are manageable and predictable, they have not many side effects and can suppress laryngeal-pharyngeal reflex during the tracheal intubation. Furthermore there are other factors such as succinylcholines use when fast intubation is needed, the wrong myorelaxant and dosage choice. Residual curarization and side effects risk increases due to these factors. As a result the patient's activation is delayed. Nevertheless myorelaxants use refusal impairs the tracheal intubation conditions, increases the arterial hypotension and heart failure risk especially in newborns and children with severe pathology. If myorelaxants is not used, comfortable conditions of surgical manipulations impossible without big analgesics and anaesthetics doses use.

[Postoperative analgesia after thoracoscopic surgeries in pediatric patients].

Postoperative pain after thoracic surgeries is characterized by intensity and long duration. The intensity of pain can be moderate or strongly expressed, the duration various from one day to months and years either after thoracotomy (TT) or thoracoscopy (TS). Pain relief is one of the most important problems of postoperative period. Adequate analgesia, lung function and temperate sedation, ventilation must be provided against the general disease, surgical injury and one-lung ventilation. TS is a less invasive method therefore pain syndrome is not very strong. There are several methods of postoperative analgesia in Pediatric patients; however the choice is limited by the patient's age. Postoperative analgesia in Pediatric patients can be provided by narcotic and nonnarcotic analgesics, neuraxial anesthesia: multimodal approach is widely used. Postoperative pain after TS needs adequate analgesia for implications prevention and to reduce the duration of hospital stay.

[Use of venovenous extracorporeal membrane oxygenation in 14 months old child with acute respiratory distress syndrome and pneumonia].

UNLABELLED: Extracorporeal life support (ECLS) is used in pediatric patients with ARDS in recent 20 years with survival rate from 50 to 67% Venovenous ECLS was used in 1 year 2 months old patient with ARDS and pneumonia developed in postoperative period after gastral esophagoplasty. Purposes of ECLS use were stabilization child's condition and normalization of gas composition of blood with relative lungs repose. Indications for ECLS were increasing respiratory failure, hypoxemia, low respiratory index (PaO2/FiO2 ratio 47.3), alveolar-arterial gradient of oxygen (A-aDO) 630 mmHg and absence of positive effect from high frequency oscillation (HFO). MATERIALS AND METHODS: ECLS was used in 1 year 2 months old patient with ARDS and bilateral pneumonia developed in postoperative period after gastral esophagoplasty. Deltasteam system (Medos Medizintechnik AG, Germany) with centrifugal pump and servoregulation of blood flow pressure was used for ECLS. Double-lumen cannula with size 12 French was used ECLS was instituted via right internal jugular vein. RESULTS: The patient did not have expressed heart failure. Thus preference was given to venovenous ECLS and not to venoarterial ECLS. Duration of ECLS use was 72 hours. Auscultation parameters and gas exchange improved haemodynamics stabilized parameters of biochemical and haematological analysis normalized and the dynamics x-ray examination was positive after the ECLS use. Patient was decannulated and extubated. CONCLUSIONS: Venovenous ECLS was an only way of life support in child with heavy ARDS and pneumonia developed in postoperative period More observations are needed for more thorough analysis and recommendations.

[Nicotinamide influence on pancreatic cells viability].

The study was undertaken to investigate the modulating effect of nicotinamide (NAm) in different concentrations and under different glucose concentrations on the viability and oxidative stress induced by streptozotocin (STZ, 5 mmol/l) and hydrogen peroxide (H2O2, 100 micromol/l) on isolated rat pancreatic cells of the Langerhans islets in vitro. Cell viability did not depend on the concentration of glucose in the range of 5-20 mmol/l, and in subsequent studies we used glucose in concentration of 10 mmol/l to protect cells against its hypo- and hyperglycemic action. Cytoprotective effect of NAm in concentrations from 5 to 20 mmol/l on cells survival was the same. It was found that the destructive action of STZ and H2O2 during 24 hours on isolated cells of the pancreas resulted in the significant cell death. It was revealed that NAm in concentration of 5 mmol/l not only had cytoprotective effects against STZ and H2O2 but also partially reduced the level of oxidative stress in the investigated cells induced by these compounds. High concentration of NAm, 35 mmol/l, causes cytotoxic effect on the viability of pancreatic islet cells and increase of oxidative stress induced by STZ and H2O2. Most likely these effects could be associated with direct modulatory action of NAm on important effector mechanisms involved in cell death, including PARP-dependent processes, or/and indirectly, through metabolic and antioxidant effects of the compound.

[Supraclavicular block during elbow joint surgeries in children].

The regional methods of analgesia are the "golden standard" of choice during trauma surgeries. The supraclavicular block of the bracheal plexus is the method of choice during the cubital joint surgeries. The purpose of the study is to improve the effectiveness of anesthesia and postoperative analgesia for surgical interventions on the cubital joint in children by developing and implementing the clinical practice of peripheral blockade of the brachial plexus by the supraclavicular access. The study included 40 children aged 5 to 12 years. The children rated as ASA I, came to the clinic on an emergency basis with cubital joint bones injuries. All the children were had surgeries on the cubital joint (closed and open repositions with osteosynthesis) with balanced regional anesthesia, the main analgesic component of which was supraclavicular brachial plexus block (by Kulenkampf-Fursaev technique). The supraclavicular block was performed in conditions of psychological comfort of the child. For the means of premedication age appropriate doses of seduxen or midazolam were intravenously administered. Intraoperative sedation was conducted by the re-introduction of benzodiazepines, and ketamine (up to 1 mg/kg/h). During the study period, the effective intraoperative analgesia, provided by supraclavicular blockade of peripheral nerves, was observed in 31 children. In 9 patients the blockade could be found to be incomplete at the second stage of the surgery (reposition). For this reason, it took the additional administration of tramal in a dose of 2 mg/kg and deepening of sedation with ketamine up to the dose of 2 mg/kg/h. The duration of effective postoperative analgesia due to long-acting local anesthetic (0.5% solution of naropin) was 8-9 hours. There were no complications registered as a result of supraclavicular. Thus, this study proves that the supraclavicular brachial plexus block provides effective intra and postoperative analgesia in trauma operations on the cubital joint in children.

[Postoperative analgesia of newborns using local anesthetic administered through wound irrigation catheter of permanent action].

The analysis of publications is devoted to the application of skin conductance monitoring in anesthesiology and intensive care. Rates of skin conductance (baseline values, the amplitude and frequency of the waves) are closely linked with the state of the sympathic nervous system. According to their dynamics it is possible to judge on the pain and stress in patients with whom the contact is difficult: newborns, infants, patients of all age groups during general anesthesia and in critical condition. According to published data monitoring skin conductance showed itself as a sensitive and promising method to identify and determine the severity of pain in all age groups, approaching by its characteristics the theses of the pain assessment perfect tool.

[Existence of two different active sites on thiamine binding protein in plasma membranes of synaptosomes].

The current work is aimed at understanding the structure and functionality of thiamine binding protein (TBP) in neural cells plasma membranes. The influence of thiamine triphosphate on thiamine binding by TBP in synaptic plasma membranes (SPM) isolated from the rat brain was investigated. It was shown that thiamine triphosphate inhibits thiamine binding activity of SPM in concurrent manner (K(i) = 1.0 +/- 0.3 microM). At the same time thiamine had no effect on thiamine triphosphatase (ThTPase) activity at the concentration range 0.5-20 microM. Otherwise, ThTPase activation with the maximum at the concentration about 2.5 microM was observed. Further, the influence of classic thiamine antagonists (amprolium, oxythiamine and pyrithiamine) on both biological activities of TBP in SPM was studied. The IC50 value for inhibition of thiamine binding on SPM by amprolium comprised 50 +/- 4.0 microM. Still, this antagonist had no effect on ThTPase activity. For the oxythiamine inhibition of both TBP activities was detected. The values of IC50 were 125 +/- 28 and 1000 +/- 95 microM for thiamine binding and ThTPase activity, respectively. The values of IC50 for thiamine binding and ThTPase activity inhibition differed by more than one order of magnitude and comprised 2.2 +/- 0.2 and 43 +/- 9 microM, respectively. The obtained data indicate that the active sites on SPM responsible for thiamine binding and ThTPase activity have different sensitivity to thiamine antagonists. Our results allow us to suppose that different active protein sites are responsible for the specific binding and for thiamine phosphates hydrolysis by TBP of synaptic membranes.

[Characteristics of thiamine triphosphatase from neural cells plasma membranes].

The kinetic parameters of the ThTP hydrolysis by synaptic plasma membranes isolated from rat brain were investigated. It was shown that the ThTPase reaction pH optimum was 7.4, the apparent K(m) was 52 microM and the apparent affinity constant for Mg2+ was 1.9 mM. The comparative analysis of the indicated parameters was done for the ThTPase activity of membrane bound (the data of present work and literature data) and cytosolic (literature data) proteins. The analysis allows us to suppose that thiamine-binding protein described earlier is the single ThTPase activity carrier in neural cells plasma membranes. It was shown that the active site of the enzyme that catalyzes the ThTP hydrolysis in neural cells plasma membranes is associated with the inside membrane surface.

[High-frequency oscillatory lung ventilation in neonatal infants with surgical diseases].

The paper presents data on the varieties and modes of the present artificial ventilation and high-frequency artificial ventilation (AV). It describes the basic impact of various ventilation modes on gas exchange, hemodynamics, and mechanical lung properties. The data on the use of high-frequency AV in neonatal infants with various surgical diseases are given. Its place and indications in malformations, such as diaphragmatic hernia and esophageal atresia, are defined. High-frequency oscillatory AV may be recommended for use as an alternative method in the treatment of respiratory failure in neonates with difuse lung lesion and in those with congenital surgical diseases when it is impossible to ensure adequate gas exchange.

[Thiamine metabolism disorders in the rat brain in experimental alcoholism and a possibility of their correction by vitamin E].

The influence of the chronic consumption of alcohol on biochemical reactions of thiamine metabolism in the rat brain is investigated. It is shown that the content of thiamine diphosphate (ThDP) in the brain tissue does not change at these conditions, though there is an essential decrease in the thiamine-kinase activity. The ability of the isolated nerve terminals (synaptosomes) to absorb labelled thiamine also decreases under this condition. The specified disturbances are probably the reason for deceleration of exchange of free (uncombined with proteins) thiamine and its phosphates in nervous cells, that results in the observed reduction in activity of pyruvate dehydrogenase complex (PDC) due to inactivation by phosphorylation. Thiamine-binding and thiaminetriphosphatase activities of thiamine-binding protein (ThBP) in the structure of synaptic plasma membranes (SPM), isolated from the rat brain in various experimental groups, have been investigated. The increase, with respect to control, in the both enzymes activity in SPM, isolated from the brain of rats with chronic alcoholism has been shown. Kinetic researches testify to an increase of affinity of SPM (ThBP) for thiamine and thiaminetriphosphate in these conditions. When vitamin E was given to animals with a model of chronic alcoholism the normalization of PDC activity in nervous cells was observed, that can testify to the transient character of these changes. Inability of vitamin E to normalize biological activities of ThBP in PMS, that has been analyzed, can testify to more deep disturbances in the structure of SPM or thiamine binding protein in their structure.

[Characteristic metabolic disturbances in the rat tissues caused by long-term use of alcohol].

In the researches carried out on rats with models of chronic alcoholism and alcohol abstinence the most vulnerable to chronic action of alcohol biochemical parameters are revealed: a level of reduced glutathione (it was estimated by the content of free SH-groups in tissues), the content of thiamine diphosphate and thiaminekinase activity in a brain, the content of folic acid in the blood, the content of ubiquinone in the cardiac muscle, RNA/DNA relation in the liver. The data obtained demonstrate first of all the negative influence of alcohol on metabolism of sulfur-containing substances and processes of transmethylation. The results of our investigation have also shown that the part of metabolic changes caused by long-term usage of alcohol, can be caused by direct influence of ethanol or its metabolites on those or other enzymatic proteins or receptors, and their functions can quickly be normalized after the abolition of alcohol (NAD+ contents, alpha-ketoglutarate dehydrogenase activity and some others). More stable changes in other parts of metabolism, that were specified earlier, may be also a result of long-term alcohol consumption.

[Method of continuous intravenous postoperative analgesia with promedol in newborn children]. / Posleoperatsionnoe obezbolivanie metodom postoiannoi vnutrivennoi infuzii promedola u novorozhdennykh detei.

Continuous intravenous infusion of promedol, 0.1 mg/kg, with additional boluses, 0.5 mg/kg, was used as postoperative analgesia in 20 newborns. Fifteen (25%) children were operated for congenital gastrointestinal defects or peritonitis, 2 children (10%)--for chylothorax, and tumor was eradicated in 3 (15%) children. On the basis of behavioral reactions, physiological indices (cardiac rate, arterial pressure, SpO2, and respiration rate/artificial pulmonary ventilation--APL) as well as of laboratory "stress" tests (blood glucose and cortisol and acid-base balance) it was proven that analgesia with continuous intravenous promedol infusion was effective. It was shown as possible to administer the promedol infusion in newborns while switching them from APL to independent breathing until the spontaneous breathing with constant positive pressure is ensured provided the pO2, pCO2 and SpO2 respiration indices are satisfactory.