Liver Thiamine Research Articles

Maternal Liver and Egg Thiamine Concentrations in Walleye from Lake Oahe, South Dakota

Thiamine, vitamin B1, cannot be synthesized by fish. Therefore, developing embryos are reliant on thiamine stores deposited during oogenesis. Thiaminase, which breaks down thiamine in predatory fish, has been suggested as the probable reason for the poor reproductive success in salmonids. Similarly, walleye Sander vitreus reproduction may also be hampered by thiaminase-containing diets. This study documented maternal liver and egg thiamine concentrations of walleye populations from the Cheyenne, Moreau, and Grand rivers of Lake Oahe, South Dakota, USA in 2000, 2001, 2002, and 2004. Thiamine concentrations were generally lowest in the eggs from the Cheyenne River. Free thiamine, thiamine monophosphate, and total thiamine were all significantly lower in eggs from the Cheyenne River compared to the Moreau and Grand Rivers. Maternal liver thiamine pyrophosphate and total thiamine followed a similar pattern. Egg survival to hatch varied significantly between locations, at 30.5%, 41.4%, and 56.8% in the Cheyenne, Moreau, and Grand Rivers, respectively, but was not significantly correlated with any form of egg thiamine. Considerable year-to-year variation was observed when data from the locations were pooled; egg free thiamine, thiamine monophosphate, and total thiamine were significantly higher in 2002. The lowest mean egg total thiamine level of 2.6 nmol/g was recorded in 2000. Liver free thiamine and thiamine monophosphate were weakly, but significantly negatively correlated with egg survival to hatch to hatch. Egg survival to hatch was significantly negatively correlated with maternal length. The results were likely impacted by the unexpected catastrophic loss of walleye forage because of flooding in 2003.

Dietary thiamin requirement of fingerling major carp Catla catla (Hamilton).

Dietary thiamin requirement of fingerling Catla catla (3.5±0.15g) was evaluated by feeding casein-gelatin-based iso-nitrogenous (350g/kg crude protein) and iso-caloric (16.72kJ/g GE) diets containing six graded levels of thiamin (0, 0.2, 0.4, 0.8, 1.6 and 3.2mg/kg dry diet) for 12weeks. Significantly (p<0.05) higher weight gain (AWG), best feed conversion ratio (FCR), protein retention efficiency (PRE), RNA/DNA ratio and haematological indices were recorded in fish fed diet containing 0.8mg/kg thiamin. Dietary thiamin supplementation improved transketolase activity (TKA) and maximum value was recorded in fish fed 0.8mg/kg thiamin beyond which stagnation in TKA activity was evident. Liver thiamin concentration was found to be maximum in fish fed diet containing 1.6mg/kg thiamin. A significant (p<0.05) consistent reduction in the hepatic thiobarbituric acid reactive substances (TBARS) activity was displayed with incremental concentration of thiamin up to 0.8mg/kg, beyond which a reverse trend was evident. However, a significant (p<0.05) improvement was noted in superoxide dismutase (SOD) and catalase (CAT) activity with the increasing level of dietary thiamin from 0 to 0.8mg/kg. Broken-line regression analysis of AWG, FCR, PRE and TKA estimated the requirement in the range of 0.74-0.79mg/kg dry diet.

Dietary thiamin requirement of fingerlingChanna punctatus(Bloch) based on growth, protein gain, liver thiamin storage, RNA/DNA ratio and biochemical composition

Dietary thiamin requirement of fingerling<i>Channa punctatus</i>(Bloch) based on growth, protein gain, liver thiamin storage, RNA/DNA ratio and biochemical composition

Landlocked Fall Chinook Salmon Maternal Liver and Egg Thiamine Levels in Relation to Reproductive Characteristics

Object:Landlocked fall Chinook SalmonOncorhynchus tshawytschain Lake Oahe, South Dakota, typically experience poor reproductive success.Introduction:Salmon diets consist of rainbow smeltOsmerus mordaxand other potentially thiaminase-containing fish that could impact reproduction.Methods:The thiamine levels of spawning female Salmon, eggs, and reproductive characteristics, were measured in 2000, 2001, 2002, 2003, and 2005.Results:Thiamine concentrations varied significantly from year-to-year, with the highest mean values recorded in 2001 at 8.70 nmol/g in maternal livers and 28.80 nmol/g in eggs. Most of the thiamine in the eggs was present as free thiamine, while most of the thiamine in maternal livers was present as thiamine pyrophosphate. The lowest recorded egg total thiamine level was 2.75 nmol/g in 2000. Egg survival to hatch ranged from 20.7% in 2005 to 35.4% in 2002, and was not correlated to egg thiamine levels. Twenty-two spawns experienced total mortality prior to hatch, and had significantly lower egg free thiamine and total thiamine concentrations than eggs from the 77 successful spawns. The eggs from spawns with total mortality were also significantly smaller than those eggs from spawns that did survive, and were produced by females that weighed significantly less. Several small, but significant, correlations were observed between egg size and egg thiamine levels, and female size and liver thiamine.There was also a significant negative correlation between the number of eggs per spawning female and egg thiamine pyrophosphate, liver thiamine monophosphate, and liver total thiamine levels.Conclusion:In general, Lake Oahe Chinook Salmon eggs show little indication of thiamine deficiency in the years sampled, indicating other factors are likely responsible for poor egg survival.

Dietary thiamin and pyridoxine requirements of fingerling Indian major carp,Cirrhinus mrigala(Hamilton)

Two experiments were conducted to quantify the dietary thiamin (experiment I) and pyridoxine (experiment II) requirements of fingerling Cirrhinus mrigala for 16 weeks. In experiment I, dietary thiamin requirement was determined by feeding seven casein–gelatin-based diets (400 g kg−1 CP; 18.69 kJ g−1 GE) with graded levels of thiamin (0, 0.5, 1, 2, 4, 8 and 16 mg kg−1 diet) to triplicate groups of fish (6.15 ± 0.37 cm; 1.89 ± 0.12 g). Fish fed diet with 2 mg kg−1 thiamin had highest specific growth rate (SGR), protein retention (PR), RNA/DNA ratio, haemoglobin (Hb), haematocrit (Hct), RBCs and best feed conversion ratio (FCR). However, highest liver thiamin concentration was recorded in fish fed 4 mg thiamin kg−1 diet. Broken-line analysis of SGR, PR and liver thiamin concentrations exhibited the thiamin requirement in the range of 1.79–3.34 mg kg−1 diet (0.096–0.179 μg thiamin kJ−1 gross energy). In experiment II, six casein–gelatin-based diets (400 g kg−1 CP; 18.69 kJ g−1 GE) containing graded levels of pyridoxine (0, 2, 4, 6, 8 and 10 mg kg−1 diet) were fed to triplicate groups of fish (6.35 ± 0.37 cm; 1.97 ± 0.12 g). Fish fed diet containing 6 mg kg−1 pyridoxine showed best SGR, FCR, PR, RNA/DNA ratio, Hb, Hct and RBCs, whereas maximum liver pyridoxine concentration was recorded in fish fed 8 mg kg−1 dietary pyridoxine. Broken-line analysis of SGR, PR and liver pyridoxine concentrations reflected the pyridoxine requirement from 5.63 to 8.61 mg kg−1 diet. Data generated during this study would be useful in formulating thiamin- and pyridoxine-balanced feeds for the intensive culture of this fish.

Severe Lactic Acidosis Associated with Burkitt’s Lymphoma

We presented this case at 11th Congress of The Turkish of Society of Medical and Surgical Intensive Care Medicine (12-15 November, Antalya, Turkey). Bu calisma 11. Ulusal Dahili ve Cerrahi Bilimler Yogun Bakim Kongresi’nde sunulmustur (12-15 Kasim 2014, Antalya, Turkiye). Address for Correspondence / Yazisma Adresi: Dr. Ramazan Coskun, e.mail: drramazancoskun@gmail.com DOI: 10.5152/dcbybd.2015.759 ©Telif Hakki 2015 Turk Dahili ve Cerrahi Bilimler Yogun Bakim Dernegi Makale metnine www.dcyogunbakim.org web sayfasindan ulasilabilir. ©Copyright 2015 by Turkish Society of Medical and Surgical Intensive Care Medicine Available online at www.dcyogunbakim.org Lactic acidosis is a metabolic acidosis caused by either overproduction or underutilization of lactic acid. Overproduction of lactic acid, known as type A lactic acidosis, is frequent in critically ill patients with hypoperfusion states. Underutilization of lactic acid, known as type B lactic acidosis, is caused by many reasons, including hepatic and liver failure, thiamine deficiency, toxins, drugs, and certain malignancies such as lymphomas and leukemias. We report a patient with severe lactic acidosis and Burkitt’s lymphoma without any signs of hypoperfusion that is relieved with chemotherapy. (Yogun Bakim Derg 2015; 6: 57-9)

Dietary Thiamin Requirement of Juvenile Grass Carp, Ctenopharyngodon idella

AbstractDietary thiamin requirement of juvenile grass carp, Ctenopharyngodon idella, was to investigate in this experiment. Eight purified diets were formulated with graded levels of thiamin (0.1, 0.6, 1.1, 2.1, 5.5, 9.8, 21.2, and 41.8 mg/kg, respectively). Each diet was fed to triplicate groups of 40 fish (initial average weight 10.7 ± 0.2 g) for 12 wk in 400‐L aquaria (R = 1 m, h = 0.6 m). Results showed that weight gain rate, specific growth rate, feed efficiency, protein efficiency ratio, and hepatosomatic indice of fish increased before dietary thiamin increased to the optimum level, then remained similar thereafter (P &gt; 0.05). Thiamin concentration in fish liver was positively correlated with dietary thiamin and it stayed in stable when dietary thiamin level exceed 5.0 mg/kg. The serum biochemical indices analysis showed that dietary thiamin had significant effects on serum triglycerides, total cholesterol, glucose, pyruvate contents, and lactate dehydrogenase activity. Body composition was unaffected by dietary thiamin. Broken‐line regression analysis showed that, a dietary thiamin level of 1.3 mg/kg diet was adequate for optimum growth, and 5.0 mg/kg for maximum liver thiamin accumulation.

In vitro immune functions in thiamine-replete and -depleted lake trout (Salvelinus namaycush)

In this study we examined the impacts of in vivo thiamine deficiency on lake trout leukocyte function measured in vitro. When compared outside the context of individual-specific thiamine concentrations no significant differences were observed in leukocyte bactericidal activity or in concanavalin A (Con A), and phytohemagglutinin-P (PHA-P) stimulated leukocyte proliferation. Placing immune functions into context with the ratio of in vivo liver thiamine monophosphate (TMP – biologically inactive form) to thiamine pyrophosphate (TPP – biologically active form) proved to be the best indicator of thiamine depletion impacts as determined using regression modeling. These observed relationships indicated differential effects on the immune measures with bactericidal activity exhibiting an inverse relationship with TMP to TPP ratios, Con A stimulated mitogenesis exhibiting a positive relationship with TMP to TPP ratios and PHA-P stimulated mitogenesis exhibiting no significant relationships. In addition, these relationships showed considerable complexity which included the consistent observation of a thiamine-replete subgroup with characteristics similar to those seen in the leukocytes from thiamine-depleted fish. When considered together, our observations indicate that lake trout leukocytes experience cell-type specific impacts as well as an altered physiologic environment when confronted with a thiamine-limited state.

Liver, plasma and erythrocyte levels of thiamine and its phosphate esters in rats with acute ethanol intoxication: A comparison of thiamine and benfotiamine administration

Thiamine and benfotiamine are vitamin B1 and pro-vitamin B1 substances, respectively. Vitamin B1 plays an essential role in energy metabolism, and its deficiency leads to neurologic and cardiovascular pathologies, as seen in alcoholics. This study presents new data about the effects of thiamine hydrochloride or benfotiamine treatment given to rats with acute alcohol intoxication, on the distribution of thiamine and its phosphate esters in liver, plasma and erythrocytes. The treatments were effective in increasing thiamine levels in plasma, erythrocytes and liver cells. The benfotiamine-treated group had its total plasma thiamine increased by 100%. In erythrocytes, thiamine levels were 4- and 25-fold higher in the groups treated with thiamine and benfotiamine, respectively, compared with the untreated groups. Liver thiamine was increased by 60% in the treated groups compared with the untreated groups. Thus, we verified the high bioavailability especially of benfotiamine within 6h of ethanol administration.

Impact of Thiamine Deficiency on T‐cell Dependent and T‐cell Independent Antibody Production in Lake Trout

Lake trout Salvelinus namaycush on thiamine-replete and thiamine-depleted diets were evaluated for the effects of thiamine status on in vivo responses to the T-dependent antigen trinitophenol (TNP)-keyhole limpet hemocyanin (TNP-KLH), the T-independent antigen trinitrophenol-lipolysaccaharide (TNP-LPS), or Dulbecco's phosphate-buffered saline (DPBS; negative control fish). Plasma antibody concentrations were evaluated for possible differences in total anti-TNP activity as well as differences in response kinetics. Associations between anti-TNP activity and muscle and liver thiamine concentrations as well as ratios of muscle-to-liver thiamine to anti-TNP activity were also examined. Thiamine-depleted lake trout that were injected with TNP-LPS exhibited significantly more anti-TNP activity than thiamine-replete fish. The depleted fish injected with TNP-LPS also exhibited significantly different response kinetics relative to thiamine-replete lake trout. No differences in activity or kinetics were observed between the thiamine-replete and -depleted fish injected with TNP-KLH or in the DPBS negative controls. Anti-TNP activity in thiamine-depleted lake trout injected with TNP-KLH was positively associated with muscle thiamine pyrophosphate (thiamine diphosphate; TPP) concentration. A negative association was observed between the ratio of muscle-to-liver TPP and T-independent responses. No significant associations between anti-TNP activity and tissue thiamine concentration were observed in the thiamine-replete fish. We demonstrated that thiamine deficiency leads to alterations in both T-dependent and T-independent immune responses in lake trout.

Gizzard Shad Thiaminase Activity and Its Effect on the Thiamine Status of Captive American Alligators Alligator mississippiensis

Adult mortality and low egg hatch rate were observed among American alligators Alligator mississippiensis in Lake Griffin, Florida, between 1998 and 2003. Previous studies show that the alligator mortality is due to neurological impairment associated with thiamine (vitamin Bt) deficiency. This study determined the rate of thiaminase activity in gizzard shad Dorosoma cepedianum, a fish often eaten by alligators, and examined the thiamine status of captive adult alligators fed only gizzard shad. We found that the thiaminase activity of gizzard shad in Lake Griffin is 16,409 +/- 2,121 pmol/g/min (mean +/- 2SEs). This high rate of thiaminase activity was present in most months and across a wide range of shad sizes. Seven alligators were captured in the wild from Lake Griffin and Lake Woodruff, held in captivity, and fed gizzard shad. We monitored blood and muscle thiamine levels throughout the experiment and liver thiamine at the end. Over a period of 6-12 months, all of the alligators maintained weight but blood and muscle thiamine levels decreased to 25-50% of the original (healthy) values. Three animals with the greatest reduction in thiamine died, demonstrating mobility impairment and neural histopathology similar to those seen in wild alligators in Lake Griffin. Two alligators were fed shad for 10 months but then treated with thiamine. These animals showed a reduction in thiamine while eating shad, but treatment restored their thiamine levels to the initial values, which were comparable to those of normal wild Lake Griffin alligators. We demonstrated that thiamine deficiency can be induced by a diet of gizzard shad and cause neurological signs and death in alligators in captivity. We conclude that the thiaminase activity in gizzard shad is high enough to cause thiamine deficiency in wild alligators when shad are a major part of their diet.

Changes in Thiamin Contents in Porcine Muscles and Liver during Growth

Changes in the thiamin contents in three types of porcine muscle and porcine liver during growth were investigated. The muscular thiamin content was lower at the newborn stage than at fetal stage, and increased after the weaning period. The liver thiamin content, however, remained unchanged from the fetal stage to 5 months old. The changes in thiamin contents were different between Landrace and Meishan pigs.

Thiamine deficiency-related brain dysfunction in chronic liver failure

End-stage chronic liver failure results in thiamine deficiency caused principally by depletion of liver thiamine stores. Chronic liver failure also leads to increased brain ammonia concentrations. Both ammonia and thiamine deficiency result in decreased activity of alpha-ketoglutarate dehydrogenase, a rate-limiting tricarboxylic acid cycle enzyme. Loss of enzyme activity results in a mitochondrial oxidative deficit in brain and consequent increases in brain lactate, oxidative/nitrosative stress, cellular energy impairment and release of proinflammatory cytokines, all of which have been described in brain in end-stage chronic liver failure. Synergistic effects of ammonia exposure and thiamine deficiency could explain the diencephalic and cerebellar symptomatology described in patients with "hepatic encephalopathy". Unsuspected brain lesions due to thiamine deficiency could explain the incomplete resolution of neuropsychiatric symptoms following the use of ammonia-lowering agents or liver transplantation in patients with end-stage chronic liver failure. These findings underscore the need for prompt, effective thiamine supplementation in all patients with chronic liver failure.

Thiamine and Fatty Acid Content of Lake Michigan Chinook Salmon

Nutritional status of Lake Michigan Chinook salmon (Oncorhynchus tshawytscha) is inadequately documented. An investigation was conducted to determine muscle and liver thiamine content and whole body fatty acid composition in small, medium and large Chinook salmon. Muscle and liver thiamine concentrations were highest in small salmon, and tended to decrease with increasing fish size. Muscle thiamine was higher in fall than spring in large salmon. The high percentage of Chinook salmon (24–32% in fall and 58–71% in spring) with muscle thiamine concentration below 500 pmol/g, which has been associated with loss of equilibrium and death in other Great Lake salmonines, suggest that Chinook appear to rely less on thiamine than other Great Lakes species for which such low concentrations would be associated with thiamine deficiency (Brown et al. 2005b). A positive correlation was observed between liver total thiamine and percent liver lipids (r = 0.53, P < 0.0001, n = 119). In medium and large salmon, liver lipids were observed to be low in fish with less than 4,000 pmol/g liver total thiamine. In individuals with greater than 4,000 pmol/g liver thiamine, liver lipid increased with thiamine concentration. Individual fatty acids declined between fall and spring. Essential omega-3 fatty acids appear to be conserved as lipid content declined. Arachidonic acid (C20:4n6), an essential omega-6 fatty acid was not different between fall and spring, although the sum of omega-6 (Sw6) fatty acids declined over winter. Elevated concentrations of saturated fatty acids (sum) were observed in whole body tissue lipid. In summary, thiamine, a dietary essential vitamin, and individual fatty acids were found to vary in Lake Michigan Chinook salmon by fish size and season of the year.

Thiamine and Fatty Acid Content of Lake Michigan Chinook Salmon

Nutritional status of Lake Michigan Chinook salmon (Oncorhynchus tshawytscha) is inadequately documented. An investigation was conducted to determine muscle and liver thiamine content and whole body fatty acid composition in small, medium and large Chinook salmon. Muscle and liver thiamine concentrations were highest in small salmon, and tended to decrease with increasing fish size. Muscle thiamine was higher in fall than spring in large salmon. The high percentage of Chinook salmon (24–32% in fall and 58–71% in spring) with muscle thiamine concentration below 500 pmol/g, which has been associated with loss of equilibrium and death in other Great Lake salmonines, suggest that Chinook appear to rely less on thiamine than other Great Lakes species for which such low concentrations would be associated with thiamine deficiency (Brown et al. 2005b). A positive correlation was observed between liver total thiamine and percent liver lipids (r = 0.53, P < 0.0001, n = 119). In medium and large salmon, liver lipids were observed to be low in fish with less than 4,000 pmol/g liver total thiamine. In individuals with greater than 4,000 pmol/g liver thiamine, liver lipid increased with thiamine concentration. Individual fatty acids declined between fall and spring. Essential omega-3 fatty acids appear to be conserved as lipid content declined. Arachidonic acid (C20:4n6), an essential omega-6 fatty acid was not different between fall and spring, although the sum of omega-6 (Sw6) fatty acids declined over winter. Elevated concentrations of saturated fatty acids (sum) were observed in whole body tissue lipid. In summary, thiamine, a dietary essential vitamin, and individual fatty acids were found to vary in Lake Michigan Chinook salmon by fish size and season of the year.

Thiamine and Fatty Acid Content of Walleye Tissue from Three Southern U.S. Reservoirs

We determined the thiamine concentration in egg, muscle, and liver tissues of walleyes Sander vitreus and the fatty acid content of walleye eggs from three southern U.S. reservoirs. In two Tennessee reservoirs (Dale Hollow and Center Hill), in which there were alewives Alosa pseudoharengus in the forage base, natural recruitment of walleyes was not occurring; by contrast in Lake James Reservoir, North Carolina, where there were no alewives, the walleye population was sustained via natural recruitment. Female walleye tissues were collected and assayed for thiamine (vitamin B1) and fatty acid content. Thiamine pyrophosphate was found to be the predominant form of thiamine in walleye eggs. In 2000, mean total egg thiamine concentrations were similar among Center Hill, Dale Hollow, and Lake James reservoirs (2.13, 3.14, and 2.77 nmol thiamine/g, respectively). Egg thiamine concentration increased as maternal muscle (r2 = 0.73) and liver (r2 = 0.68) thiamine concentration increased. Walleye egg thiamine does not appear to be connected to poor natural reproduction in Tennessee walleyes. Threadfin shad Dorosoma petenense, which are found in all three reservoirs, had higher thiaminase activity than alewives. Six fatty acids differed among the walleye eggs for the three reservoirs. Two were physiologically important fatty acids, arachidonic acid (20:4[n-6]) and docosahexaenoic acid (22:6[n-3]), which are important eicosanoid precursors involved in the regulation of biological functions, such as immune response and reproduction.

The Effect of Thiamine Injection on Upstream Migration, Survival, and Thiamine Status of Putative Thiamine‐Deficient Coho Salmon

AbstractA diet containing a high proportion of alewives Alosa pseudoharengus results in a thiamine deficiency that has been associated with high larval salmonid mortality, known as early mortality syndrome (EMS), but relatively little is known about the effects of the deficiency on adults. Using thiamine injection (50 mg thiamine/kg body weight) of ascending adult female coho salmon Oncorhynchus kisutch on the Platte River, Michigan, we investigated the effects of thiamine supplementation on migration, adult survival, and thiamine status. The thiamine concentrations of eggs, muscle (red and white), spleen, kidney (head and trunk), and liver and the transketolase activity of the liver, head kidney, and trunk kidney of fish injected with thiamine dissolved in physiological saline (PST) or physiological saline only (PS) were compared with those of uninjected fish. The injection did not affect the number of fish making the 15‐km upstream migration to a collection weir but did affect survival once fish reached the upstream weir, where survival of PST‐injected fish was almost twice that of controls. The egg and liver thiamine concentrations in PS fish sampled after their upstream migration were significantly lower than those of uninjected fish collected at the downstream weir, but the white muscle thiamine concentration did not differ between the two groups. At the upper weir, thiamine levels in the liver, spleen, head kidney, and trunk kidney of PS fish were indistinguishable from those of uninjected fish (called “wigglers”) suffering from a severe deficiency and exhibiting reduced equilibrium, a stage that precedes total loss of equilibrium and death. For PST fish collected at the upstream weir, total thiamine levels in all tissues were significantly elevated over those of PS fish. Based on the limited number of tissues examined, thiamine status was indicated better by tissue thiamine concentration than by transketolase activity. The adult injection method we used appears to be a more effective means of increasing egg thiamine levels than immersion of eggs in a thiamine solution.

Cellular and molecular aspects of thiamin uptake by human liver cells: studies with cultured HepG2 cells

The liver is an important site for thiamin metabolism, utilization, and storage. Little is known about the mechanism of thiamin uptake by the human liver. In this study, we examined cellular and molecular aspects of the human liver thiamin uptake process using the human-derived liver HepG2 cells as a model system. Our studies showed that the initial rate of thiamin uptake to be: (1) Na +-independent and occurs with no detectable metabolic alterations in the transported substrate, (2) highly pH-dependent with diminished uptake upon decreasing incubation buffer pH from 8.0 to 5.0, (3) higher following cell acidification compared to unacidified control cells, (4) saturable as a function of concentration with an apparent K m of 7.7±1.6 μM, (5) inhibited by the thiamin structural analogues oxythiamin and amprolium but not by the unrelated organic cations tetraethylammonium (TEA) and N-methylnicotinamide (NMN), and (6) inhibited in a concentration-dependent manner by the membrane transport inhibitor amiloride. Both of the recently cloned human thiamin transporters, i.e., SLC19A2 and SLC19A3, were found to be expressed in liver HepG2 cells with the former being the predominant form. High promoter activity of the predominant form, i.e., SLC19A2, was detected in HepG2 cells, and the minimal region of the SLC19A2 promoter required for its basal activity in these cells was found to be encoded in a sequence between −356 and −36 and has multiple putative cis-regulatory elements. Mutation of a number of these putative cis-elements diminished promoter activity of the SLC19A2 minimal region. These results show the involvement of a specialized carrier-mediated mechanism for thiamin uptake by human liver HepG2 cells. In addition, SLC19A2 was found to be the predominant thiamin uptake carrier expressed in these cells and its promoter displays a high level of activity in them.

Determination of thiamine (vitamin B,) and riboflavin (vitamin B2) in meat and liver by high-performance liquid chromatography

HPLC methods described so far for the determination of thiamine and riboflavin in meat samples have used mostly fluorescence detection. The aim of this work was to elaborate a suitable method with UV detection for this purpose and to compare the thiamine and riboflavin contents obtained for meat and liver samples from various pig groups. Homogenized spare rib, chop, ham and fiver samples were treated with acid and heated (at 121°C, 30 min), followed by enzymatic digestion to release the vitamins. After a clean-up procedure the simultaneous determination of thiamine and riboflavin was performed with a Nucleosil ODS (3 μ m) packed column at 45°C. The mobile phase was phosphate buffer (pH 3.0)-acetonitrile (84:16, v/v) containing 5 m M sodium heptanesulphonate. The relative standard deviation was 5% for thiamine and 12% for riboflavin in meat and 8% for thiamine and 5% for riboflavin in liver for four parallel determinations.

The effects of copper status on thiamine metabolism in sheep fed a high sulfur diet

The effect of Cu status on selected aspects of thiamine metabolism was studied in sheep exposed to high dietary S over a period of 14 wk. Nine cross-bred 2-mo-old female lambs were used. The animals were divided into three groups (n = 3) and offered a basal diet containing 0.63% S (0.45% as sulfate) and 14 mg thiamine kg−1 DM. Copper and Mo were variable ingredients. Sheep in group 1 received a 14 mg Cu kg−1 DM diet, whereas those in groups 2 and 3 received a 6 mg Cu kg−1 DM diet. To precipitate Cu insufficiency, group 3 received an additional 20 mg Mo kg−1 DM diet. The concentration of blood thiamine tended to increase in sheep from group 1, but decline in sheep from group 3 which also had a lower concentration of Cu in plasma. In these groups, a similar trend was observed in thiamine and Cu concentrations of duodenal fluid. Liver thiamine tended to be higher (P = 0.09) in group 3 sheep than in group 1 and 2 sheep. However, the concentration of thiamine in the kidney and cerebral cortex did not differ among the groups. Copper concentration was lowest in the liver and brain, but highest in the kidney of sheep from group 3. The erythrocyte thiamine pyrophosphate (TPP) effect increased (P &lt; 0.035) in sheep in groups 2 and 3 during the 8th week on the diet and in all sheep during the 13th week. We conclude that Cu plays an important role in the metabolism of thiamine in the gastrointestinal tract, as well as systemically. Key words: Sulfur, molybdenum, copper, thiamine, interactions, sheep