Serum thiamine

These various reports stress the need to supplement parenteral nutrition with thiamine-containing vitamins unless there is adequate dietary intake, and to monitor serum thiamine and erythrocyte transketolase activity so that supplementary thiamine can be given in good time, if necessary intravenously (45). Giving thiamine will not rectify the various disorders if hepatic function is severely disturbed, because then thiamine is not phosphorylated and hence remains physiologically inactive. 

Maschke, M., Weber, J., Bonnet, U., Dimitrova, A., Bohrenkamper, J., Sturm, S., Muller, B.W., Gastpar, M., Diener, H.C., Forsting, M., and Timmann, D., 2005. Vermal atrophy of alcoholics correlate with serum thiamine levels but not with dentate iron concentrations as estimated by MRI. Journal of Neurology. 252 704—711. 

Tallaksen, C.M., Bohmer, T., and Bell, H., 1992b. Blood and serum thiamin and thiamin phosphate esters concentrations in patients with alcohol dependence syndrome before and after thiamin treatment. Alcoholism Clinical and Experimental Research. 16 320-325. 

Lactobacillus plantarum is a reliable reagent for pantothenate in foods, tissues, and biologic fluids (M4, T5). It is also useful in studying the pantothenic acid content of tissues, in particular the liver. As with thiamine, the pantothenic acid levels in serum of the mother at term, although higher than in other individuals, are 5 times less than the fetus... 

The answer is B. While all of the listed conditions are consistent with lethargy and developmental defects, the lactic acidosis rules out pyruvate kinase deficiency. Thiamine and niacin deficiencies are unlikely due to the lack of effect of vitamin supplementation. Excess pyruvate is the source of the elevated alanine in the serum. The clinical findings are thus consistent with pyruvate carboxylase deficiency, which is associated with severe hypoglycemia due to fasting due to impaired gluconeogenesis. 

Many cells require media supplemented with complex B vitamins, while other vitamins are presumably supplied by the addition of serum to culture media. Nevertheless, when serum-free media are employed, not only the water-soluble vitamins should be provided, but also the lipid-soluble ones, such as biotin, folic acid, niacin, panthotenic acid, thiamine, and ascorbic acid, as well as the vitamins B12, A, D, E, and K. 

The reaction mixture contained 80 /xL of 130 mM Hepes-67 mM Tris buffer (pH 7.4) 10 ju,L each (to give final concentration of 1 mM) of NAD, thiamine pyrophosphate, coenzyme A, MgCl2, and dithiothreitol 20 /xL of tissue extract or enzyme source, and 30 /xL of bovine serum albumin (1 mg). The reaction was started by adding 20 fiL of a-ketoglutarate to give a final concentration of 10 mM After incubation at 30°C for 1, 5, or 20 minutes for purified enzyme from bovine heart, brain, or liver mitochondria, or platelet homogenates, the reaction was stopped by addition of 20 /xL of 60% perchloric acid and the denatured protein was removed by centrifugation. A 10 /xL aliquot was used for HPLC analysis. 

Systemic evaluation of the patient includes a complete blood count, blood chemistry, thiamine level, urinalysis, serum vitamin B12 and folate levels, heavy metal screening (lead, mercury, arsenic), and tests for megaloblastic anemia. The hair may also be tested for indications of toxicity. 

After documenting a serum vitamin B12 deficiency, the patient should receive 300 mg oral thiamine each week and 1,000 g intramuscular hydroxocobalamin each week for 10 weeks.The sooner this therapy begins, the better the prognosis. The hydroxocobalamin fc>rm of vitamin B12 appears to be more effective than cyanocobalamin. In terms of recovery from the amblyopia, cessation of smoking or drinking does not appear to produce remission unless the patient concurrently improves their diet.Thus it is unnecessary and, in practice, difficult to persuade patients who are habitual abusers of tobacco and alcohol to stop the use of such agents. Improvement of dietary status seems to be the most important factor in recovery. 

A young man developed marked deterioration in his vision and oscillating vision, despite normal optic fundi, during parenteral nutrition he went on to develop a characteristic Wernicke s encephalopathy, confirmed by characteristic findings on MRI brain scan (42). The serum vitamin Bi concentration was 110 pg/ml (reference range 200-500). He responded fuUy to thiamine 300 mg/day in addition to betamethasone for 4 weeks. 

Direct measurement of circulating thiamine concentration may be made in plasma, erythrocytes, or whole blood. The plasma (or serum) concentration is thought to reflect recent intake and is mainly unphosphorylated thiamine at low concentration (around 10 to 20nmol/L). Because the erythrocyte contains approximately 80% of the total thiamine content of whole blood,mainly as the pyrophosphate, and erythrocyte thiamine stores deplete at a similar rate to other major organs, HPLC measurement of TPP in erythrocytes is a good indicator of body stores. Typical HPLC methods include a protein precipitation step, precolumn or postcolumn formation of the fluorophore thiochrome, usually with alkaline ferricyanide and isocratic separation. The method is easily standardized with pure... 

A thorough nutrition-focused history and physical examination is the most valuable means of screening patients for vitamin deficiency or toxicity (Table 135-9). It is uncommon to see a single vitamin deficiency usually multiple vitamin deficiencies occur with general malnutrition. Single vitamin deficiencies do occur, however. Thiamine deficiency may result in lactic acidosis and encephalopathy, whereas pernicious anemia due to vitamin B12 deficiency has been reported with increasing frequency, especially in the elderly. Recently, the incidence of vitamin D deficiency has increased in children. Laboratory assessment may be useful to confirm the clinical suspicion of a deficiency state. The first indication of a deficiency is usually a fall in circulating serum concentrations of the vitamin or its coenzyme. 

Bohrer D, do Nascimento PC, Ramirez AG, Mendonca JKA, de Cavalho LM, Pomblum SCG, Determination of thiamine in blood serum and urine by high-performance liquid chromatography with dried injection and post-column derivatization. Microchem J 2004 28 71-6. 

Fig. 11.8.4. HPLC of thiamine in human serum (a) and human cerebrospinal fluid (b). Chromatographic conditions stationary phase, pBondapak C18 (10 pm) reversed phase (300 X 3.9 mm I.D.) mobile phase, methanol-aqueous sodium citrate, pH 4.0, 0.05 mol/1 (45/55, v/v), sodium 1-octanesulphonate 10 mmol/1 temperature, ambient flow rate, 1.2 ml/min detection, post-column fluorescence (excitation at 367 nm, emission at 435 nm). Peaks 1, saUcylamide 2, thiamine. Reproduced from Wielders and Mink (1983), with permission.

Affinity chromatographic purification of kallikrein from human serum 378 Affinity chromatographic isolation of thiamine-binding protein from 379 chicken egg-white... 

Choline esterase, estrogens and, IX, 231, 233 formation, thiamine and, VI, 77 serum,... 

Thiamine (pharmaceutical preparations and serum) Tianeptine and some of its metabolites (pharmaceutical preparations)... 

Chen, H., Zhu, J., Cao, X., and Fang, Q., 1998. Flow injection on-line photochemical reaction coupled to spectrofluorimetry for the determination of thiamine in pharmaceuticals and serum. Analyst. 123 1017-1021. 

Serum pyruvate normal thiamine status 62% low thiamine no symptoms 38% (ETK-A >20% serum pyruvate > 79 gmol/L) and gross clinical thiamine deficiency (w = 6) Barry 1985... 

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