MTX withdrawal and observation for a short period should be considered in the initial management of patients who develop LPD while on MTX therapy. Responses were consistently observed, but not limited to patients in whom EBV was detected by ISHS or PCR. Further studies are required to confirm these findings and to evaluate the role for EBV in LPD that occur in patients receiving MTX.

Previously, the metabolism of alpha-tocopherol was considered to involve the opening of the chroman structure because of its oxidation to tocopherylquinone. In contrast, we describe here 2,5,7,8-tetramethyl-2(2'-carboxyethyl)-6-hydroxychroman (alpha-CEHC) as the major urinary metabolite of alpha-tocopherol that appears in human urine after vitamin E supplementation. It is formed directly from alpha-tocopherol without previous oxidative splitting of the chroman ring. The correlation of alpha-tocopherol intake, plasma alpha-tocopherol concentrations, and urinary excretion of alpha-CEHC in human volunteers supplemented with RRR-alpha-tocopherol dosages ranging from 0 to 800 mg/d was examined. HPLC and gas chromatography-mass spectroscopy analysis revealed that alpha-CEHC was only excreted when a plasma threshold of 7-9 mumol alpha-tocopherol/g total lipid was exceeded. This concentration was obtained by a daily intake of approximately 50-150 mg alpha-tocopherol. We suggest that alpha-CEHC excretion indicates a saturated binding capacity of vitamin E in the plasma and thus may be considered to be a marker of optimum vitamin E intake.

Oxygen radicals are commonly accepted mediators in the tumour necrosis factor-mediated nuclear factor κB (NFκB) signalling cascade, but evidence for their role during interleukin-1 (IL-1) signalling is lacking. To test the involvement of hydroperoxides we investigated whether IL-1-induced NFκB activation could be influenced by glutathione peroxidases (GPx). These enzymes remove hydroperoxides with various specificities for the hydroperoxide substrate. By overexpressing phospholipid hydroperoxide glutathione peroxidase (PHGPx), which characteristically reacts with lipophilic hydroperoxides, the roles of H2O2 and lipidhydroperoxides were assessed. A human umbilical endothelial cell line, ECV 304, was stably transfected with the genes for both PHGPx and selenophosphate synthetase (selD), which provides selenophosphate for selenoprotein biosynthesis. When grown in selenium-deficient culture medium, the double-transfected clone (ECVPHGPx+SelD+) expressed 5-fold higher (P < 0.005) PHGPx activity (measured by phosphatidylcholine hydroperoxide removal) than controls. The rate of H2O2 removal was also significantly (P < 0.01) higher in this clone. When grown with high levels of extracellular selenium (up to 100 nM selenite), PHGPx activity and H2O2 removal were enhanced substantially in control cells and transfected cells. Under these conditions, PHGPx activity was 1.7-fold (P < 0.005) higher in ECVPHGPx+SelD+, but H2O2 removal was the same as in controls. IL-1-induced NFκB activation was inhibited by selenium supplementation in control cells. In ECVPHGPx+SelD+ under conditions of selenium restriction, IL-1 induced NFκB activation only to a similar extent as under conditions of selenium supplementation in controls, and activation was abolished with 50 nM sodium selenite. These results show that overexpressed PHGPx is sufficient to inhibit NFκB activation, and suggests that NFκB activation by IL-1 is mediated by a preferential substrate of PHGPx, such as a fatty acid hydroperoxide, rather than by H2O2, the preferred substrate of the more abundant cytosolic GPx.

Flaxseed protein isolates were prepared by micellisation (FM) and isoeletric precipitation (FI). The in¯uence of preparation conditions on composition and functional properties was investigated. Contents of 0.6% phytic acid and 2.3% pentosans were found for FI, whereas FM was almost phytic acid-free and had a low content of pentosans (0.6%). Chromatography and electrophoresis identi®ed the 11S globulin (linin) as the main protein fraction in both isolates. Protein solubility, water-and oil-binding capacities, emulsi®cation and rheological properties of dispersions and gels were measured at pH 8 and 3. For the latter, interactions of protein with phytic acid and pentosans are highly probable. FI possesses a lower solubility (about 40±50%) and an overall higher water-binding capacity than FM. For FI dispersions a higher storage modulus G' than loss modulus G@ was measured, clearly pointing to the formation of protein networks. Moreover, FI formed stronger gels than FM (G' about ®vefold). The emulsifying activity, however, was distinctly lower for FI. These results point to enhanced complexation and aggregation of the isoelectric-precipitated protein isolate. INTRODUCTIONRecently, interest in¯axseed or linseed (Linum usitativissimum L) in the food and feed markets has increased owing to the reported health bene®ts attributed to¯axseed components. 1±3 The nutritional value of¯axseed meal and protein isolates has been reported to approach the corresponding data of soybean products, with a slightly lower net protein utilisation and protein ef®ciency ratio of the former. 4,5 Flaxseed protein products contain considerable amounts of mucilage (pentosans) as well as phytic acid, which distinctly in¯uence their functional properties. For example, Dev and Quensel 6±8 studied the functional properties of a¯axseed protein isolate and various protein concentrates with varying pentosan content. The pentosan content, amounting to about 5% in the isolate and between 6 and 9% in the concentrates, exerted a marked effect on the emulsifying and foaming properties and water-and oil-binding capacities as well as on the behaviour in complex food systems. However, the data do not verify that the functional properties can be attributed unambiguously to the pentosan content, owing to the additional effect

An improved procedure for the isolation and purification of the 11 S globulin from sunflower seeds (helianthinin) is described, including a combined purification by gel chromatography and ionexchange chromatoThe protein has a sedimentation constant of szo, = 12.8 x lo-'' s, a STOKES radius of 57 A and a diffusion constant of 3.76 x lo-' cm2 s-' (the last two derived from gel chromatographic analysis). Hence it follows a molecular weight of M, = 305000. The isoelectric point determined by isoelectric focusing lies at pH 4.7.High contents of glutamic (26%) and aspartic (14%) acid and arginine (9.7 %) as well as a low content of sulphur containing amino acids are characteristic for the amino acid composition. 59 % of the acidic amino acids are present in an amidated form. The globulin contains 12 disulphide bridges per molecule. graphy.Helianthinin is the main storage protein in sunflower seed [l]. It represents a typical 11 S globulin with a molecular weight near 300000, dissociation properties depending on pH and ionic strength, a low content of a-helix, a relatively high amount of p-conformation, and a high content of arginine, glutamic and aspartic acid (2-51. In the present paper an improved purification for the globulin combining gel filtration and ion-exchange chromatography, the corrected amino acid composition, the content of amide-nitrogen and SS/SHgroups, and some physico-chemical properties of the globulin are described. Material and Methods Protein isolationGround dehulled sunflower seeds were defatted with diethyl ether and extracted with a 5% solution of sodium chloride in a cold room. The protein was precipitated with cold water and twice chromatographed on Sephadex G-200 as described in a previous paper [6].

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