Showing papers on "Thiamine published in 1977"
TL;DR: The abnormality in transketolase persisted through serial passages in tissue culture in cells grown in medium containing excess thiamine and no ethanol, indicating that the aberrations were genetic rather than dietary.
Abstract: We studied a thiamine-requiring enzyme in cultured cells from four patients with the Wernicke-Korsakoff syndrome to determine whether these patients have a genetic predilection to thiamine...
355 citations
76 citations
TL;DR: In this article, the reactions of Thiamine·HCl (ThH), TMP and TPP have been studied in aqueous solutions (pH ∼3-4) at room temperature.
50 citations
TL;DR: Small intestinal mucosa accumulated labelled thiamine in a phosphorylated form, while gastric and colonic mucosa, as well as muscular layers of all gastrointestinal segments studied, did not.
Abstract: Surgical specimens of human gastrointestinal mucosa and muscle were incubated in vitro with thiaminethiazole-2-14C. Labelled thiamine uptake was uphill in mucosal tissues and downhill in muscle. Small intestinal mucosa accumulated labelled thiamine in a phosphorylated form, while gastric and colonic mucosa, as well as muscular layers of all gastrointestinal segments studied, did not.
47 citations
TL;DR: Two separate binding proteins, one specific for folate and the other for thiamine, have been isolated from membrane fragments of Lactobacillus casei and the ability of these compounds to inhibit the transport of the corresponding vitamins is paralleled by their ability to inhibit binding.
Abstract: Two separate binding proteins, one specific for folate and the other for thiamine, have been isolated from membrane fragments of Lactobacillus casei. Purification to homogeneity was achieved by fractionation of the Triton-solubilized proteins with microgranular silica (Quso G-32) and Sephadex G-150. Amino acid analyses revealed that the folate (Mr = 25,000) and thiamine (Mr = 29,000) binders have unusually low polarity constants, 0.32 and 0.26, respectively. Evidence obtained with intact cells has established a direct role for these binding proteins in transport of the corresponding vitamins: (A) In each case, the processes of binding and transport showed similarities in substrate affinities and repression by excess vitamin in the growth medium. (B) Competition studies employing amethopterin, 5-formyl tetrahydrofolate, and 5-methyl tetrahydrofolate (for folate) and thiamine monophosphate and thiamine pyrophosphate (for thiamine) have shown that the ability of these compounds to inhibit the transport of the corresponding vitamins is paralleled by their ability to inhibit binding. (C) Amethopterin-resistant mutants which are defective in folate transport have a comparable defect in ability to bind folate. (D) Amethopterin-resistant cells which (compared with the parent cell line) contain folate transport systems with altered affinities for amethopterin also contain binding proteins whose affinities for amethopterin have changed by equivalent amounts. (E) Both the transport and binding of folate by one of the mutants were stimulated (approximately 3-fold) in parallel by the addition of mercaptoethanol.
45 citations
Journal Article•
TL;DR: In vivo and in vitro experiments carried out, various amounts of ethanol or acetaldehyde were added to the supernatant of brain and liver of intact rats, and transketolase activity was determined.
Abstract: To clarify the effect of ethanol on thiamine metabolism and activity of transketolase, a thiamine dependent enzyme, in vivo and in vitro experiments were carried out. For the in vivo experiment, rats were separated into four groups: Group 1, thiamine sufficient diet with no ethanol administered; group 2, thiamine sufficient diet and ethanol administered by stomach tube; group 3, thiamine deficient diet with no ethanol administered; group 4, thiamine deficient diet and ethanol administered. After three weeks, the rats were killed, then thiamine levels and the activity of transketolase were assayed. Thiamine concentration in brains and livers of ethanol fed rats were lower than that in control rats. Urinary thiamine was higher in ethanol administered rats than in controls. The increase in the liver transketolase activity by the in vitro addition of cocarboxylase (TPP effect) was higher in group 3 than in group 4 although original transketolase activity was lower in group 4. For the in vitro experiment, various amounts of ethanol or acetaldehyde were added to the supernatant of brain and liver of intact rats, and transketolase activity was determined. Inhibition by acetaldehyde to transketolas was about 10 times higher than that by ethanol.
40 citations
TL;DR: It was concluded that the TPP effect was frequently misleading in subjects with gross thiamine deficiency (Wernicke'S encephalopathy) and it was suggested that erythrocyte transketolase activity may be the best parameter to use in assessingThiamine status with the erythroc yte apotransketolases assay.
Abstract: Summary
:Thiamine status in alcoholism. Beverley Wood, Kerry J. Breen and D. G. Penington, Aust. N.Z. J. Med., 1977, 7, pp. 475–484.
The erythrocyte transketolase assay was used to seek biochemical evidence of thiamine deficiency in 265 alcoholic persons attending an inner city Australian hospital. Fifty patients were found to have recent vitamin therapy and were excluded from further study. Wernicke's encephalopathy was diagnosed in 24 subjects (11.3%). The thiamine pyrophosphate (TPP) effect was elevated in only 13 of the 24 patients with Wernicke's encephalopathy; a much closer correlation was observed with erythrocyte transketolase activity which was depressed in 21 persons with this diagnosis. Low erythrocyte transketolase activity (32.6%) was more frequently seen than an elevated TPP effect (24-7%) in the overall group of 215 subjects. Of 47 patients with a low erythrocyte transketolase activity which failed to return to normal after the addition of TPP in vitro, only ten patients had liver disease. Twelve patients with Wernicke's encephalopathy studied following thiamine hydrochloride in vivo showed complete biochemical response despite the presence of biopsy proven severe liver disease in two patients and the lack of response of low erythrocyte transketolase activity to TPP in vitro in eleven of the twelve patients. Fiftyfive patients were studied before and after thiamine in vivo. Seventeen of these subjects had severe liver disease but only two of the 17 had low ETKA which failed to respond to TPP in vitro; both responded biochemically to thiamine hydrochloride in vivo. In the remaining 38 patients without evidence of severe liver disease, 14 had low ETKA which failed to return to normal with TPP in vitro; three of these failed to respond biochemically to thiamine hydrochloride in vivo. These data indicated that apparent deficiency of erythroc yte apotransketolase was infrequently linked with the presence of liver disease and that liver disease did not appear to interfere with the biochemical response to thiamine in vivo. Urinary thiamine excretion measured in 79 subjects did. not correlate with any means of expression of the transketolase assay or with clinical thiamine deficiency. It was concluded that the TPP effect was frequently misleading in subjects with gross thiamine deficiency (Wernicke'S encephalopathy) and it was suggested that erythrocyte transketolase activity may be the best parameter to use in assessing thiamine status with the erythrocyte transketolase assay. Finally, it is postulated that severe thiamine deficiency per se may lead to deficiency of erythrocyte apotransketolase which has been previously ascribed to liver damage.
37 citations
TL;DR: Thiamine treatment was successful in correcting biochemical and clinical symptoms of a patient with congenital lactic acidosis, muscular hypotonia and severe ataxia and the mechanism of its action is probably based on activation of pyruvate dehydrogenase through interference in the physiologic regulation.
Abstract: A patient with congenital lactic acidosis, muscular hypotonia and severe ataxia is reported. The aetiology of his disease was found to be a deficiency of pyruvate dehydrogenase (E.C. 4.1.1.1.). Thiamine treatment (1.8 g/day) was successful in correcting biochemical and clinical symptoms. The mechanism of its action is probably based on activation of pyruvate dehydrogenase through interference in the physiologic regulation.
37 citations
TL;DR: A naturally occurring neurological disease occurred in six dogs fed cooked meat and was characterized by bilaterally symmetrical spongy change and necrosis of brainstem nuclei with a lesion distribution pattern similar to that in thiamine deficient foxes and cats.
Abstract: A naturally occurring neurological disease occurred in six dogs fed cooked meat. Clinical signs were anorexia, progressive spastic paraparesis, recumbency, convulsions and death. The disease was characterized by bilaterally symmetrical spongy change and necrosis of brainstem nuclei with a lesion distribution pattern similar to that in thiamine deficient foxes and cats. An associated thiamine deficiency was evidenced by decreased thiamine levels in the blood of one dog and in the food of another, and rapid remission of clinical signs in a dog given thiamine hydrochloride. Thermal destruction of thiamine through cooking of the foods probably caused the dietary deficiency.
35 citations
33 citations
TL;DR: The clinical data in these patients point to a specific diet deficiency of thiamine, causing a bilateral optic neuropathy, causingVisual loss occurring in two patients taking prolonged carbohydrate‐restrictive diets is reported.
Abstract: Visual loss occurring in two patients taking prolonged carbohydrate-restrictive diets is reported. The clinical data in these patients point to a specific diet deficiency of thiamine, causing a bilateral optic neuropathy. A discussion of current concepts of thiamine deficiency in neuroophthalmic disorders is presented. It is recommended that patients on low-carbohydrate diets for prolonged periods of time should receive thiamine supplements.
TL;DR: It appears that differences in the patient groups studied here reflect variations in apoenzyme levels rather than thiamine status, and the low ETKA values in diabetes mellitus seem to be due to a reduced apoen enzyme level resulting from the disease itself rather thanThiamine deficiency.
TL;DR: In some rats rehabilitation with thiamine was begun on the 19th day, and after 23 days, brain cerebroside content was still lower in the experimental group than in both controls, which may suggest damage of the myelin sheath.
Abstract: In an attempt to create a model of human infantile beriberi, pregnant rats were fed, from the 10th day of pregnancy through lactation, a low-thiamine diet. Controls were either pair-fed or offered a nutritionally complete diet ad libitum. Dams exhibited symptoms of thiamine deficiency after 30 days on the experimental diet, whereas their pups displayed signs of thiamine deficiency from the 14th postnatal day. Brain transketolase activity was depressed in day-old thiamine-deficient pups, and brain pyruvic acid levels were elevated after the 7th postnatal day. From the 14th postnatal day, brains of thiamine-deficient pups contained less phospholipids, cerebrosides and cholesterol than those of both controls. On the 21st day, weight and lipid content of brains of thiamine-deficient and of pair-fed pups were lower than those of normal controls. In some rats rehabilitation with thiamine was begun on the 19th day, and after 23 days, brain cerebroside content was still lower in the experimental group than in both controls. Since cerebrosides are an essential component of myelin, this finding may suggest damage of the myelin sheath.
TL;DR: The results indicate that calcium plays a role in binding thiamine in nerve membrane structures, which have a specific role in the conduction process of nervous tissues, and magnesium may play an important role inThiamine‐dependent enzyme systems in the liver.
Abstract: —
Wistar rats were divided into 4 groups and the following different synthetic diets were given for 1 month: group 1, calcium- and magnesium-deficient; group 2, calcium-deficient, magnesium-sufficient; group 3, calcium-sufficient, magnesium-deficient; group 4, calcium-sufficient, magnesium-sufficient (normal diet). After 1 month on these dietary regimens, the rats were killed. In calcium-deficiency (groups 1 and 2), thiamine concentration in synaptosomal and myelin-membrane fractions in the brain had decreased and the ratio of free thiamine to total thiamine and non-protein bound thiamine amount had increased in the brain. In magnesium-deficiency (groups 1 and 3), thiamine concentration in the liver and activities of thiamine-dependent enzymes in liver had decreased. These results indicate that calcium plays a role in binding thiamine in nerve membrane structures, which have a specific role in the conduction process of nervous tissues. In contrast, magnesium has little effect on thiamine in nervous tissues but may play an important role in thiamine-dependent enzyme systems in the liver.
TL;DR: Thiamine deficiency in the experimental animals was confirmed by blood transketolase assays and pair-fed controls showed no clinical signs.
Abstract: In the course of multiple episodes of thiamine deficiency in the rhesus monkey, the triad of anorexia, apathy, and hind limb weakness is the earliest clinical manifestation. In later episodes, nystagmus, abducens paresis, midline ataxia, dysmetria, and congestive heart failure are also seen. With the exception of dysmetria, the neurologic signs promptly respond to thiamine administration. Pair-fed controls showed no clinical signs. Neither peripheral neuropathy nor edema was observed. Thiamine deficiency in the experimental animals was confirmed by blood transketolase assays.
TL;DR: Electron microscopic investigations on sciatic and plantar nerves of thiamine deficient and starved rats show a distally pronounced axonal degeneration, and the distal accentuation of the early changes indicates a dying-back mechanism of axonal disintegration.
Abstract: Electron microscopic investigations on sciatic and plantar nerves of thiamine deficient and starved rats show a distally pronounced axonal degeneration. The changes are present in starved and thiamine deficient animals, but the deficient animals are more severely affected. The earliest alterations consist of an increase of mitochondria and a proliferation of vesicular elements of the endoplasmic reticulum. They are followed by loop formations of the axon membrane, clustering and disintegration of neurotubules and neurofilaments, axonal shrinkage and finally myelin disruption. The distal accentuation of the early changes indicates a dying-back mechanism of axonal degeneration.
Journal Article•
TL;DR: Thiamine-pyrophosphatase activity was present only in the particulate fractions (especially in microsomes), being completely absent from the supernatant.
Abstract: Starting from mucosal cells, isolated from rat small intestine, subcellular fractionation was carried out. Four fractions were prepared and characterized by marker enzymes and electron microscopic examination: nuclei plus microvilli, mitochondria, microsomes and supernatant. Thiamine-pyrophosphokinase activity was localized mainly in the supernatant fraction, with minor amount in mitchondria and microsomes. On the contrary thiamine-pyrophosphatase activity was present only in the particulate fractions (especially in microsomes), being completely absent from the supernatant.
TL;DR: When thiamine, nicotinic acid, pyridoxine, or calcium pantothenate was singly omitted from an adequate, fully-defined, aseptic dietary medium, newly-hatched larvae were unable to grow beyond the 2nd instar, and most died as 3rd or 4th instars.
Abstract: When thiamine, nicotinic acid, pyridoxine, or calcium pantothenate was singly omitted from an adequate, fully-defined, aseptic dietary medium, newly-hatched larvae were unable to grow beyond the 2nd instar. In the absence of riboflavin, folic acid, biotin or choline, a few larvae developed to pupae, but most died as 3rd or 4th instars. Minimal concentrations of the essential vitamins required initially in the medium for optimal growth were established and compared with similar data in the literature for another mosquito.
TL;DR: Pancreatic slices incubated in glucose medium take up oxygen and glucose and liberate pentose, pyruvate and proteins and thiamine deficiency decreases oxygen consumption but increases liberation of pentose and proteins by pancreatic slices.
Abstract: Pancreatic slices incubated in glucose medium take up oxygen and glucose and liberate pentose, pyruvate and proteins. Thiamine deficiency decreases oxygen consumption but increases liberation of pentose, pyruvate and proteins by pancreatic slices.
TL;DR: The serotype, agglutinability, hemolytic effect, virulence, and nutritional requirements of the Listeria were compared and it seems that these properties are not consistently linked.
Abstract: The composition of a minimal medium suitable for the demands of modern genetical work is described. The nutritional requirements of some 15 strains ofL.monocytogenes were studied on this medium. DL-6,8-thioctic acid was not essential. The organisms also grew without thiamine but for a convenient colony size this vitamin had to be used. The presence of Fe++, Mg++, and Ca++ ions as well as a low redox potential supplied by thioglycollate was necessary. There was some difference in the amino acid requirements of the strains. The most common demand was for leucine, iso-leucine, valine, and cysteine.
Journal Article•
TL;DR: The data suggest that thiamine pyrophosphokinase is an adaptive enzyme, the activity of which depends on theThiamine content of the cells, whereas no decrease of the enzyme activity has been found in the brain.
Abstract: The activity of thiamine pyrophosphokinase has been measured in liver, heart muscle and brain of normal and thiamine deficient rats. The activity measurement has been performed by use of thiamine-35S as substrate and separation of the reaction products by high voltage electrophoresis. KM has been determined as 7.1.10(-6) mol/l. The activity of thiamine pyrophosphokinase is reduced in liver and heart muscle of thiamine deficient rats significantly, whereas no decrease of the enzyme activity has been found in the brain. The content of thiamine pyrophosphate has been measured in the liver of normal and thiamine deficient rats. Injection of thiamine to deficient rats normalized the content of thiamine pyrophosphate in the liver within 6 hours. Our data suggest that thiamine pyrophosphokinase is an adaptive enzyme, the activity of which depends on the thiamine content of the cells.
TL;DR: Tests on 50 chronic alcoholics demonstrated that there was a reduced supply of thiamine and riboflavine and that pyridoxine determination with the GOT activation test would seem to be influenced by alcohol or by metabolic processes induced by it and is therefore not suitable in the presence of chronic alcoholism.
Abstract: Tests on 50 chronic alcoholics demonstrated that there was a reduced supply of thiamine (measured with the transketolase activation test) and riboflavine (glutathione reductase test) compared with results obtained in 1152 healthy controls. A high risk of thiamine deficiency was present in 45.4% of male and 50% of female alcoholics; risk of riboflavine deficiency was 11.1% and 16.7%, respectively. Corresponding results in the normal controls were 2% for thiamine and 0.4% for riboflavine deficiency. There was a significant relationship between enzymatic values of thiamine deficiency, on the one hand, and anaemia, abnormal liver functions (bilirubin, gamma-globulin) and low diastolic arterial pressure, on the other. Enzymatic riboflavine values also correlated with haemoglobin content, so that it is assumed that the anaemia is associated with the reduced thiamine or riboflavine supply. Enzymatic determination of pyridoxine with the GOT activation test would seem to be influenced by alcohol or by metabolic processes induced by it and is therefore not suitable in the presence of chronic alcoholism.
TL;DR: Isotope competition experiments revealed that the incorporation of [35S]cysteine is not significantly diluted by the presence of methionine, homocysteine, and glutathione, leaving the origin of the five-carbon unit still in doubt.
TL;DR: It was found that the positively charged quaternary nitrogen atom is the primary locus of inhibition, while alkyl groups in the molecule play a secondary role through hydrophobic association with the enzyme.
Abstract: Eighteen compounds related to thiamine were assayed for their inhibitory potency against electric eel acetylcholinesterase at pH 7.00 and 8.25 by Ellman's method. Data in the form of progress curves were fitted to the integrated form of the rate equation for linear, mixed-type Michaelis-Menten kinetics. The values of Ki thus obtained were compared in order to define the loci of inhibition on the thiamine molecule. It was found that the positively charged quaternary nitrogen atom is the primary locus of inhibition, while alkyl groups in the molecule play a secondary role through hydrophobic association with the enzyme. Protonation of the inhibitors was seen to be an important factor.
TL;DR: Thiamine pyrophosphate-ATP phosphoryltransferase, the enzyme that catalyzes the synthesis of thiamine triphosphate, has been found in the supernatant fraction of rat liver and was found to be bound to a high molecular weight protein which comes out in the void volume of Sephadex G-75, and is not dialyzable.
TL;DR: A simple, rapid, and sensitive method for the fluorometric assay of proteins, where proteins are spotted on a Kieselguhr G plate and N -chlorinated by spraying with a solution of sodium hypochlorite and the fluorescence of thiochrome is measured with a scanning fluorometer.
TL;DR: Thiamine disulfide and O-benzoyl thiamine Disulfide, which are thiolfrom derivatives of thiamines, strongly inhibited thiamin transport in Saccharomyces cerevisiae.
Abstract: Both thiamine disulfide and O-benzoyl thiamine disulfide, which are thiolfrom derivatives of thiamine, strongly inhibited thiamine transport in Saccharomyces cerevisiae. The inhibition appeared to be due to a high affinity of the analogs for yeast cell membranes, in which thiamine transport component(s) may be integrated.
TL;DR: The incorporation into the thiazole moiety of thiamine of several labeled compounds has been studied on short time incubations of washed-cells suspensions on the basis of radioactivity and carbon originates from cysteine which is the likely direct donor of sulphur.
TL;DR: In this paper, the vitamin contents of six rural Nigerian foods were estimated before and after cooking and the implications of these losses for the peasants are discussed, including losses of vitamin C in all the diets were between 40 and 100%.