VITAMIN B1 BIOLOGICAL FUNCTION IMPLEMENTATION IN THE BLOOD OF PATIENTS WITH STOMACH CANCER UNDER SURGICAL INTERVENTION

Background. The probability of undergoing surgery always predetermines the state of stress in a person; therefore, it is advisable to search for ways to optimize and (or) reduce this unfavourable effect. Objective. To find out the mechanism of vitamin B1 antistress activity during surgery. Material and methods. Metabolism intensity was investigated on donors’ blood lysates (n = 19) and those of patients with stage III stomach cancer (n = 64), referred to an elective surgery, aged 51-70. The blood was taken from the cubital vein three days before the operation, after premedication, during the most traumatic moment of the operation, after extubation, as well as on the first and third days of the postoperative period. The surgery was performed under combined multicomponent anesthesia using nitric oxide, sodium hydroxybutyrate, and epidural block. Thiamine and thiamine diphosphate kinase activities were assessed by the concentration of the formed thiamine di- and triphosphates of the vitamin. The activities of thiamine mono-, di- and triphosphatases were determined by the release of inorganic phosphate. The concentration of inorganic phosphate was recorded colorimetrically. The content of B1 and its derivatives in the blood was determined by the method of ion-pair reversed-phase HPLC. Results. There has been observed an increased content of thiamine monophosphate and that of free thiamine in the blood of donors and patients with stomach cancer. The registered rate of the hydrolytic thiamine monophosphatase reaction is not high. At the stages of premedication and maximum trauma of surgical exposure, the concentration of monophosphoric ester rapidly decreases alongside with monophosphatase activation. Therefore, the thiamine monophosphate hydrolysis is the rate-limiting link of vitamin B1 metabolism. The level of free thiamine remains persistently increased at all stages of surgical treatment. Thiamine monophosphatase activity is manifested at two pH optima – of 6.0 and 9.0. Thiamine monophosphate hydrolysis at pH of 9.0 is catalyzed by alkaline phosphatase. At pH of 6.0, in addition to thiamine monophosphoric ester, the enzyme hydrolyzes only p-nitrophenyl phosphate, flavin mononucleotide and phosphotyrosine, that allows it to be classified as hepatic acid phosphatase. The noted changes in B1 metabolism under stress concern mainly non-coenzyme forms - thiamine mono-, triphosphate, and free thiamine, which are used at the stages of thiol reduction as important components of insulin synthesis. Conclusions. The use of vitamin B1 allows to optimize the development of the stress response at all stages of surgical treatment. Its protective effect is achieved through the activation of the insulin-synthetic function of the pancreas, which increases the level of immunoreactive insulin in the blood. The formation of the most favorable physiological conditions for insulin synthesis provides an increased background of free thiamine, which is created due to the hydrolysis of noncoenzyme forms of the vitamin. The relationship between thiamine metabolism and B2 exchange and regulation of intracellular signaling pathways has been traced.

Thiamine monophosphatase: a genuine marker for transganglionic regulation of primary sensory neurons.

Thiamine monophosphatase (TMPase) has been selectively localized in small dorsal root ganglion cells and in their central and peripheral terminals. Light microscopic localization of TMPase, and its alterations due to transganglionic effects, are identical with those of fluoride-resistant acid phosphatase (FRAP), but are not contaminated by the ubiquitous lysosomal reaction inevitable in trivial acid phosphatase-stained sections. TMPase is inhibited by 0.1 mM NaF, which is slightly less than the concentration needed to inhibit FRAP (0.2-0.4 mM). It is assumed that TMPase and FRAP are identical enzymes. In the perikaryon of small dorsal root ganglion cells, TMPase is located in the cisterns of the endoplasmic reticulum and in the Golgi apparatus. The central terminals of these cells are scalloped (sinusoid) axon terminals, surrounded by membrane-bound TMPase activity. Central terminals outline substantia gelatinosa Rolandi throughout the spinal cord, as well as the analogous nucleus spinalis trigemini in the medulla. TMPase-active central terminals outline "faisceau de la corne postérieure" in the sacral cord, as well as Lissauer's tract in the thoracic, upper lumbar, and sacral segments, and the paratrigeminal nucleus and the terminal (sensory) nucleus of the ala cinerea in the brainstem. Peripheral terminals displaying TMPase activity are fine nerve plexuses of C fibers. The TMPase activity of the central terminals disappears after dorsal rhizotomy in the course of Wallerian degeneration, and is depleted in the course of transganglionic degenerative atrophy (after transection of the related peripheral sensory nerve). TMPase is an outstanding genuine marker for the study of transganglionic regulation in Muridae.