Contents Of Plasma Research Articles

Origin of aldosterone in the rat heart.

Aldosterone has been demonstrated in the perfusate of the ex situ rat heart and heart homogenates; however, the origin of aldosterone in the heart is controversial, with some reporting a primary role for extraadrenal synthesis within the heart, and others finding that all of the aldosterone in the heart is sequestered from the circulation. In an attempt to resolve this controversy, we measured the aldosterone and corticosterone contents of plasma and hearts of rats on a normal salt (NS), low salt (LS), or high salt (HS) diet, adrenalectomized (ADX+HS), and ADX with aldosterone replacement or deoxycorticosterone excess (ADX+HS+DOC) before tissue harvest. The sodium content of the diet had no significant effect on corticosterone levels in the plasma or heart. LS significantly increased, whereas HS decreased the aldosterone content of plasma and heart compared with NS. Corticosterone levels in both plasma and heart and aldosterone levels in plasma of ADX-HS rats were undetectable in most individuals and were extremely low in very few. Although plasma aldosterone was undetectable, aldosterone was measurable in 30% of the hearts of 84 ADX+HS rats, albeit at low levels. The aldosterone and corticosterone contents of the hearts of ADX+HS+DOC were similar to those of ADX+HS, indicating that aldosterone synthase and 11beta-hydroxylase, not substrate, are the limiting factors for extraadrenal synthesis of corticosteroids in the heart. In conclusion, we found that the level of aldosterone content in the healthy rat heart in vivo is significantly lower than that reported elsewhere and reflects plasma levels in intact rats.

The Fatty Acid Profile of Buccal Cheek Cell Phospholipids Is a Noninvasive Marker of Long-Chain Polyunsaturated Fatty Acid Status in Piglets

The fatty acid pattern of cheek cell phospholipids has been proposed as a noninvasive marker of long-chain polyunsaturated fatty acid (PUFA) status. However, the cheek cell phospholipid fatty acid pattern has been compared only with that of plasma and erythrocytes. The objective of this study was to assess the extent to which the fatty acid profile of cheek cell phospholipids reflects that of tissue phospholipids. Piglets (n = 31; 6 d old) were fed five formula diets differing in total fat and fatty acid composition. After 14 d of consuming the assigned diets, cheek cell plasma, erythrocyte, liver, muscle, adipose tissue, retina and brain samples were collected for determination of the phospholipid fatty acid patterns. There were significant correlations between the cheek cell phospholipid content of most PUFA and the content of these fatty acids in tissue phospholipids (r = 0.509-0.951, P < 0.01). The cheek cell phospholipid content of most of the PUFA, except 20:4(n-6), reflected that of other tissue phospholipids as well as, or nearly as well as the contents of plasma and/or erythrocyte phospholipids. The correlations between the 22:6(n-3) contents of cheek cell, plasma, or erythrocyte phospholipids and those of brain and retina phospholipids were relatively poor (r = 0.596-0.737, P < 0.001). We conclude that the fatty acid pattern of cheek cell phospholipid can be used as a noninvasive marker of PUFA status, but it is not a better index than the pattern of plasma or erythrocyte phospholipids, particularly for assessing the fatty acid pattern of organs with slow fatty acid incorporation and/or turnover rates.

Production performance of dairy cows after the dietary addition of clinoptilolite

Clays are frequently proposed for the addition to dairy cattle diets to reduce the transfer of mycotoxins in milk. This study examined the effect of the addition of Clinoptilolite to the diet of lactating dairy cows on milk production and milk composition. Thirty-two lactating Holstein cows (average lactation length: 142 d) were blocked according to milk production, parity, and days of lactation for assignment to one of two dietary treatments: control diet; control diet + Clinoptilolite, 200g/d. The control diet was based on corn and alfalfa silages, hay and concentrates, and did not contain aflatoxins above the safe level. The experimental period lasted 76 days. The Clinoptilolite supplementation did not affect milk yield and milk composition other than urea contents. The urea level in milk was negatively affected by Clinoptilolite addition (control group 29.7 mg/100 ml vs Clinoptilolite group 31.3 mg/100ml). The dietary addition of Clinoptilolite did not change pH, ammonia content and VFA molar percentages in the rumen. No dietary effect on mineral contents of blood plasma (Na, K, Zn, and Ca) was observed. In case of clinoptilolite use in dairy cattle feeding, scarce negative effect on milk production and quality are expected.

Forms of cytochrome P450 in the liver microsome of oxidized frying oil-fed guinea pigs.

The aim of this study is to investigate the influence of oxidized frying oil (OFO) on the induction of individual forms of cytochrome P450 (CYP450) in guinea pigs. The OFO samples were obtained by frying potato chips in soybean oil at 200+/-5 degrees C for 24 h. Sixteen male weaning guinea pigs were fed for 12 wk on a diet which included 15% of either OFO or fresh soybean oil supplemented with 300 ppm ascorbic acid. It was demonstrated that guinea pigs fed with the OFO diet (D300) exhibited inferior growth rates and lower feed efficiency than the control group (F300). The vitamin C contents of plasma, liver, and kidney in the D300 group were lower than those in the F300 group. Further, the thiobarbituric acid-reactive substance content in D300 liver and kidney was higher than that in the F300 equivalent. The liver UDP-glucuronyl-transferase activity in the D300 group was higher than that in the F300 group, and there was no difference in comparing the glutathione-S-transferase activity levels of the two groups. Notably, the total CYP450 content and the NADPH-cytochrome c reductase activity were significantly elevated in the D300 group. The ethoxyresorufin O-deethylase activity, which mainly represents CYP1A1 activity, for the detection of CYP450 isozyme characteristics was elevated more in the D300 than in the F300 group. There was no difference in the pentoxyresorufin O-dealkylase activity, which mainly reflects the CYP2B isozyme, between the two groups. However, the quantity of CYP1A1 isoform determined in the D300 group did not differ from that in the F300 group, as revealed by SDS-PAGE and Western blot testing. Our results demonstrate that the relative enzyme activity to CYP1A1-like activity of the guinea pig hepatic xenobiotic metabolizing enzyme system may be induced by OFO feeding, but more advanced research is needed to identify the predominant form of CYP450 isozyme induced as a result of this condition.

Effect of docosahexaenoic acid supplementation of lactating women on the fatty acid composition of breast milk lipids and maternal and infant plasma phospholipids

To determine whether docosahexaenoic acid (DHA) supplementation of breast-feeding mothers increases the DHA contents of breast milk and infant plasma phospholipids (PPs), breast-feeding women were randomly assigned to 3 DHA-supplementation groups (170-260 mg/d) or a control group. Group 1 (n = 6) consumed an algae-produced high-DHA triacylglycerol; group 2 (n = 6) consumed high-DHA eggs; group 3 (n = 6) consumed a high-DHA, low-eicosapentaenoic acid marine oil; and group 4 (n = 6) received no supplementation. From before to after supplementation (2 and 8 wk postpartum), mean (+/-SD) maternal PP DHA increased in groups 1, 2, and 3 by 1.20 +/- 0.53, 0.63 +/- 0.82, and 0.76 +/- 0.35 mol% of fatty acids, respectively (23-41%), but decreased in group 4 by 0.44 +/- 0.34 mol% (15%). Breast-milk DHA of groups 1, 2, and 3 increased by 0.21 +/- 0.16, 0.07 +/- 0.11, and 0. 12 +/- 0.07 mol%, respectively (32-91%) but decreased in group 4 by 0.03 +/- 0.04 mol% (17%). Mean infant PP DHA in groups 1, 2, and 3 increased by 1.63 +/- 0.79, 0.40 +/- 1.0, and 0.98 +/- 0.61 mol%, respectively (11-42%), but only by 0.18 +/- 0.74 mol% (5%) in group 4. Correlations between the DHA contents of maternal plasma and breast milk and of milk and infant PPs were significant. Breast-milk and maternal and infant PP 22:5n-6 concentrations were lowest in group 2. DHA supplementation increases the plasma and breast-milk DHA concentrations of lactating women, resulting in higher PP DHA concentrations in infants.

Reduction of the oxidative injury to the rabbits with established atherosclerosis by protein bound polysaccharide from Coriolus vesicolor.

Recent evidence has emerged that macrophage glutathione (GSH) content and selenium dependent glutathione peroxidase (SeGSHPx) activity are inversely related to cell-mediated oxidation of LDL, and intervention means to enhance the macrophage GSH-SeGSHPx status may contribute to attenuation of the atherosclerotic process. Our previous works showed that protein bound polysaccharide (PSK) injected intraperitoneally could enhance SeGSHPx activity and mRNA content of mouse macrophages. The aim of the present study is to demonstrate whether PSK can reduce the oxidative injury to the established atherosclerotic rabbits. Using the established atherosclerotic rabbit model, we studied the effect of PSK on oxidatively modified LDL (Ox-LDL), lipoperoxide (LPO) cholesterol contents and SeGSHPx activities of plasma and tissues (aorta, heart and liver) in the established atherosclerotic rabbits. As compared with the control group, Ox-LDL, LPO and cholesterol contents were much lower; SeGSHPx activities and SeGSHPx/LPO ratios were much higher in plasma and tissues (aorta, heart and liver); and the lesion area of aortae was reduced in the PSK group. Through the increment of SeGSHPx activity in macrophages and aortae, PSK enhances their antioxidation potentiality and improves the antioxidant/prooxidant imbalance in them, and thus decreases Ox-LDL, LPO and cholesterol contents of plasma and tissues, and regresses lesion area of aortae in the established atherosclerotic rabbits.

Serum hepatocyte growth factor as an index of extensive catabolism of patients awaiting liver transplantation

BACKGROUNDWhole body catabolism as the result of intrahepatic metabolic derangement is common in liver transplant candidates. However, individual nutritional assessment parameters lack sensitivity and specificity in determining energy status of...

Discrimination of structural isomers of amphetamine using carbon dioxide negative‐ion chemical ionization mass spectrometry

The negative‒ion chemical ionization mass spectra of a group of structural isomers of amphetamine have been studied using carbon dioxide as the reagent gas. Characteristic and reproducible differences are observed for each member of the set implying that this technique offers a means of distinguishing among groups of amphetamine isomers. Characteristic adducts to the molecular ion are observed in the form (M–[H]+[O]) and (M–[H]+[CO2]). Descriptions of some fragments are given based on the mass spectral behaviour of a set of analogue compounds and the results of oxygen‐18 labelled carbon dioxide reagent gas experiments. Contents of the carbon dioxide plasma and their impact on various analytes is also discussed.

The Effects of Supplemental Microbial Phytase on the Performance and Utilization of Dietary Calcium, Phosphorus, Copper, and Zinc in Broiler Chickens Fed Corn-Soybean Diets

A 3-wk feeding trial with 180 sexed day-old broiler chickens was conducted to study the efficacy of microbial phytase (Natuphos 1000) on growth performance, relative retention of P, Ca, Cu, and Zn, and mineral contents of plasma and bone. Treatments involved a normal P level corn-soybean diet, a low-P diet, and a low-P plus phytase (600 phytase units/kg) diet. Phytase supplementation increased (P ≤ 0.05) body weight in male and female chickens by 13.2 and 5.8%, respectively, at 21 d. The improvements yielded body weights comparable to those obtained on the normal P diet. Phytase supplementation overcame (P ≤ 0.05) the depression of feed intake observed on the low-P diet. Treatments had no effect on feed:gain ratio. Phytase supplementation of the low-P diet increased (P ≤ 0.05) the relative retention of total P, Ca, Cu, and Zn by 12.5, 12.2, 19.3, and 62.3 percentage units, respectively, in male chickens. Microbial phytase increased the plasma P by 15.7% and reduced (P ≤ 0.05) the Ca concentration by 34.1%, but had no effect on plasma concentrations of Cu or Zn. Phytase supplementation increased the percentage ash in both head and shaft portions of dry, fat-free tibia bone to a level comparable to that of the normal-P diet. Phytase supplementation had no effect on the concentration of any of the minerals measured in whole tibia ash but did increase (P ≤ 0.05) the DM percentage of P and Ca in tibia head of male chickens by 0.65 and 1.4 percentage units, respectively. These results show that microbial phytase supplementation of a low-P diet increased growth and relative retention of total P, Ca, Cu, and Zn and improved bone mineralization in broiler chickens.

Species differences in the concentration of acetylcholine, a neurotransmitter, in whole blood and plasma

Various concentrations of acetylcholine (ACh) were detected in samples of bovine, goat, horse, porcine, rat and sheep blood and plasma using a specific, sensitive radioimmunoassay. The ACh levels in whole blood in bovine and horse samples were about 40- and ten-fold higher, respectively, than in humans, but levels comparable to those in humans were measured in porcine samples. Goat, rat and sheep samples had lower whole blood ACh concentrations than those of humans. When plasma samples were assayed, the ACh contents of bovine and porcine plasma were found to be about two- to five-fold those of human. On the other hand, levels in horse, goat, rat and sheep samples were much lower than in humans. The ratio of the ACh contents of plasma to whole blood was high in porcine and rat samples, indicating that porcine and rat blood ACh is distributed mostly in the plasma, while in the other species tested most of the ACh is present in the blood cells. These results demonstrate that variable levels of ACh are present in the blood of different species, and that the distribution of ACh in the blood constituents varies according to species.

The effect of ethanol and diazepam on the fatty acid composition of plasma and liver phospholipids in the rat.

The main interest of the present study was to determine possible alterations in fatty acid composition in rat plasma and liver phospholipids (PL) caused by chronic ethanol consumption, diazepam treatment and chronic consumption of alcohol and diazepam together. Chronic ethanol consumption (11 g/kg/d) elevated the proportion of plasma saturated (SFA) and mono-unsaturated fatty acids (MUFA), and decreased the most important polyunsaturated fatty acids (PUFA) in plasma and liver PL. The alterations in fatty acid composition in liver PL indicate that ethanol can change the composition of cell membrane lipids. Diazepam treatment (10 mg/kg/d) elevated the contents of SFA and MUFA in plasma PL. On the other hand, diazepam produced a drastic decrease in 22:6n-3 docosahexaenoic acid (DHA) in plasma and liver PL. These changes in plasma PL fatty acid composition indicated a disturbance of fatty acid metabolism. The changes in fatty acid contents of plasma and liver PL were the greatest in rats treated with a combination of ethanol and diazepam, in which there was a summation of the effects of ethanol or diazepam alone, and the effects were intensified by an ethanol-diazepam interaction.

Discrimination between RRR- and all-racemic-α-tocopherols labeled with deuterium by patients with abetalipoproteinemia

The ability to discriminate between stereoisomers of a-tocopherol was studied in five patients with abetalipoproteinemia (ABL) because an impairment in secretion of apolipoprotein B-containing lipoproteins might impede the normally enhanced plasma transport of RRR-a-tocopherol. An oral dose containing 3.7 g of each 2R,4′R,8′R-α-[5-C 2H 3]tocopheryl acetate (d 3RRR-α-tocopheryl acetate) and 2RS,4′RS,8′RS-α-[5,7-(C 2H 3),]tocopheryl acetate (d 6all rac-α-tocopheryl acetate) was administered, then the labeled and unlabeled a-tocopherol contents of plasma and red blood cells from multiple blood samples obtained at selected times up to 72 h following the dose were quantitated. ABL plasma contained about 1%–10% of the d 3-RRR-a-tocopherol concentrations of normal subjects given only 150 mg of each isotope. Three of the patients discriminated between forms of a-tocopherol with ratios of RRR-/allrac-α-tocopherol ≥ 1.8, similar to normals. These data suggest that the hepatic tocopherol binding protein is present and functional in ABL patients. Although two of the patients did not discriminate between stereoisomers of a-tocopherol, it is likely that this resulted from nearly a complete block in very low density lipoprotein (VLDL) secretion. Thus, the ability of ABL patients to absorb and transport orally administered vitamin E is markedly impaired and variable among patients.

Analysis of trace elements in biological materials by microwave induced plasma-mass spectrometry

Analytical conditions have been established for determination of trace elements in biological materials by microwave induced plasma-mass spectrometry (MIP-MS). Possible elemental contaminants were checked in the water and reagents used, and during the wet-ashing process. Among 72 elements tested, contamination by Na, Mg, K, Ca, Fe, Ba, and Pb were observed. This contamination was estimated to occur mainly during the process of preparing samples due to the water, reagents and surroundings. Contamination by Ca, Mg, Zn and Pb from tubes for storage was also observed. Adequate conditions for multielement analyses in plasma and bone samples were evaluated. Both plasma and bone samples were digested by the wet-ashing technique before applying MIP-MS. The recovery rates of elements added were decreased depending on the contents of plasma or bone samples in the measuring solutions. The interfering effects of matrix modification due to organs were improved by correction with an internal standard. Recovery rates of elements added, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Mo, Cd, Sn, Ba, Pb and fourteen lanthanide elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) were within 100 +/- 5% in analytical samples containing 1% volume of human plasma when Ga or Tl was used as the internal standard. Recoveries of Sn and Zn in the bone samples containing 0.1% bone as the original bone material, however, were 100 +/- 10% even after correction by the internal standard, suggesting the necessity of combined use of standard addition methods. The concentrations of V, Cr, Mn, Fe, Cu, Zn, Rb, Sr, Mg, and Ca in plasma from two healthy women were determined by MIP-MS. The data were consistent with the values reported elsewhere, and agreed very closely with those obtained by atomic absorption spectrometry. The accuracy of the values obtained by this method was confirmed using standard reference materials. These results indicate that MIP-MS is a useful method for multielement determination of biological materials.

Folate Metabolism and Deposition in Eggs by Laying Hens

White Leghorn hens were fed purified folate-deficient diets or commercial corn- and soybean meal-based diets supplemented with different amounts of folic acid. The folate contents of egg yolk and blood plasma from these hens were estimated with an isotope-dilution, radioligand-binding assay. Folates in egg yolk were concentrated approximately 43-fold relative to the blood plasma from which they were derived. Yolk and plasma folate concentrations became saturated with increasing dietary folate. Hens fed a commercial, folate-sufficient diet (0.72 mg folate/kg) produced eggs with slightly less than half of the maximal folate content. Based on tritium deposition in egg yolk and egg white, the biological half-life of [ 3H]folic acid injected intraperitoneally into two folate-sufficient hens was ∼15 days, while it was ≥40 days in two hens fed a purified folate-deficient diet (0.07 mg folate/kg) that also reduced egg production. Radioactivity in egg yolk was concentrated more than 100-fold relative to egg white in both cases. The [ 3H]folates remaining in the hens at the end of the experiment were substantially more concentrated in liver than in kidney, heart, or skeletal muscle. The specific radioactivity of folates in the liver of folate-deficient hens after 78 days was almost 10 times greater than in folate-sufficient hens after 39 days. Laying hens have highly efficient conservation and delivery systems for folates.

Specific increase of L-DOPA levels in plasma upon infusion of tyrosinase containing liposomes

1. 1. The present paper reports the effects of liposome-entrapped tyrosinase (EC 1.14.18.1. l-Tyrosine, l-3,4-dihydroxyphenylalanine: oxygen oxidoreductase) infusion on the catecholamine contents of rat plasma. The actions of liposomes and free tyrosinase have also been investigated. 2. 2. From the experiments, evidence has been obtained that liposome-entrapped tyrosinase is able to affect specifically l-3,4-dihydroxyphenylalanine ( l-DOPA) levels which increase dramatically. 3. 3. The possible use of liposome-entrapped tyrosinase to raise l-DOPA levels in catecholamine related disorders is discussed. 4. 4. Liposomes without tyrosinase provoke no significant changes of catecholamine or l-DOPA levels while free tyrosinase does induce a change but in a less constant fashion than the liposome-entrapped enzyme.

Multi-element analysis of biological tissues by inductively coupled plasma mass spectrometry: healthy sprague dawley rats

The normal inorganic contents of bone, brain, erythrocyte, heart, kidney cortex, kidney medulla, liver, lung, muscle and plasma from healthy Sprague Dawley rats were established by using a general method developed for inductively coupled plasma mass spectrometric multi-element determinations of most of the elements present in biological tissues. The most characteristic elemental pattern of each tissue was identified via a statistical multivariate analysis and a principal component analysis helped to elucidate the correlations between elements and tissues.

A Fast HPLC Analysis of Cholesterol and Cholesteryl Esters in Avian Plasma

Abstract A rapid HPLC method for the quantitation of free cholesterol and cholesteryl esters in avian plasma is described. After extraction with isopropanol, free cholesterol and cholesteryl esters were eluted with acetonitrile-isopropanol (50:50, v/v) on a short, 3μ, reversed-phase column within 24 min and detected at 210 nm. The assay was used to evaluate differences in the free cholesterol and cholesteryl esters contents of blood plasma from Japanese quail genetically selected for high and low plasma cholesterol levels. Selection has altered cholesteryl ester distribution in quail, and may provide clues regarding genetic control of cholesterol metabolism.

Discrimination between forms of vitamin E by humans with and without genetic abnormalities of lipoprotein metabolism.

To study the mechanisms of discrimination between various forms of vitamin E, four normal subjects, one patient with lipoprotein lipase deficiency, and three patients with abnormal apolipoprotein B-100 production were given an oral dose containing three tocopherols labeled with differing amounts of deuterium (2R,4'R,8'R-alpha-(5,7-(C2H3)2)tocopheryl acetate (d6-RRR-alpha-tocopheryl acetate), 2S,4'R,8'R-alpha-5-(C2H3)tocopheryl acetate (d3-SRR-alpha-tocopheryl acetate), and 2R,4'R,8'R-gamma-(3,4-2H)tocopherol (d2-RRR-gamma-tocopherol). The tocopherol contents of plasma, red cells, and lipoproteins were measured up to 76 h after the dose. In normal subjects all three tocopherols were absorbed and secreted in chylomicrons with equal efficiencies. Both d2-gamma- and d3-SRR-alpha-tocopherols peaked at similar concentrations in the other lipoprotein fractions, then decreased similarly, but 2-4 times more rapidly than did d6-RRR-alpha-tocopherol. A lipoprotein lipase-deficient patient and a patient with prolonged production of chylomicrons with absent apolipoprotein B-100 also demonstrated the lack of discrimination between tocopherols during absorption. Despite abnormal apolipoprotein B-100 production in two patients, the "VLDL" was preferentially enriched in d6-RRR-alpha-tocopherol. Our results show that there is no discrimination between the three tocopherols during absorption and secretion in chylomicrons, but subsequently there is a preferential enrichment of very low density lipoprotein (VLDL) with RRR-alpha-tocopherol. Catabolism of this VLDL results in the maintenance of plasma RRR-alpha-tocopherol concentrations.

Pedogenesis of Two Forest Soils (Kandiustults) Derived from Metamorphosed Granite in Korea

AbstractSoils derived from granite rocks occupy 66% of the land in Korea. Two soils from the southern part of Korea formed on metamorphosed granite under forest vegetation, containing high amounts of ferruginous chlorite, were studied to evaluate weathering and formation of clay minerals. The soils are deeply weathered, strongly acid, low in organic matter and cation‐exchange capacity (CEC), and the amounts of clay in the very thick Bt horizons are almost three times higher than in the BC horizons. Micromorphology of the thin O horizon showed common characteristics of moder humus and evidence of high biological activity. High contents of coarse grains and low plasma impart to the E horizon an enaulic‐related distribution pattern. The most striking micromorphological features are multilaminated, generally limpid ferriargillans in the Bt and BC horizons. While some chlorites are intact or partly weathered in the E and BC horizons, they are entirely weathered in the Bt horizons. High clay contents in the Bt horizons are not only due to clay translocation, but also to intensive in situ mineral weathering in this zone. The most significant pedogenic processes, as revealed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), were formation of Fe oxyhydroxide and tubular halloysite from the weathering of chlorite and other primary minerals. Iron oxides imparted a typical red color to the soils. Total chemical analysis of clays revealed extensive loss of Ca, K, and Na and concentration of Fe and Al. Almost equal proportions of Al and Si oxides support a clay fraction dominated by halloysite and kaolinite. Mineralogical studies of clays in the Bt horizon showed that, while feldspars were partly weathered, chlorite, under a well‐drained, acid, humid temperate to semitropical environment, was completely weathered to kaolinite, halloysite, hematite, goethite, gibbsite, and a chlorite‐vermiculite intergrade, probably hydroxy‐interlayered vermiculite (HIV). Some dioctahedral mica appeared to be resistant in the soils.

Thiamin Contents of Cerebrospinal Fluid, Plasma and Erythrocytes in Cerebellar Ataxias

Free thiamin and thiamin monophosphate have been found in the cerebrospinal fluid, plasma and in erythrocytes of patients suffering from ataxia of different origins. In erythrocytes, thiamin pyrophosphate was also measured. In a limited number of cases, uptake of 14C-thiamin by erythrocytes was found as well. Controls were hospitalized patients affected by chronic neurological diseases without any clinical sign of thiamin deficiency. The results showed a significant decrease in thiamin and thiamin monophosphate in the cerebrospinal fluid and in the plasma of ataxic subjects, in comparison to controls. In erythrocytes, only thiamin pyrophosphate levels had decreased. The uptake of 14C-thiamin by erythrocytes was similar in both ataxic and control groups. These results were comparable to those observed in thiamin-deficient individuals, like alcoholic patients, and prompted further investigation into thiamin metabolism in these diseases.