Foods which increase tissue arachidonic acid levels have been proposed to increase thrombosis tendency, presumably through increased platelet aggregation. This study examined the effect of doubling the dietary arachidonic acid (20:4n-6) using meat- or fish-based diets on the systemic production of prostacyclin (PGI2) and thromboxane (TXA2) in 29 healthy, nonsmoking adults. There were three, 3-wk low-fat dietary periods (< 15% energy as fat) in which subjects consumed a vegetarian diet for 1 wk followed by 2 wk on diets containing meat or fish as sources of 20:4n-6. Between each diet period, there was a 3-wk washout period, during which subjects returned to their normal diets. The level of 20:4n-6 consumed during the last 2 wk of each study was approximately double the usual intake (mean 140 mg/d), while the mean eicosapentaenoic acid (20:5n-3) content of the diets varied from 1 mg/d on the white meat diet to 70 mg/d on the red meat diet and to 847 mg/d on the fish diet. The serum phospholipid (PL) 20:4n-6/20:5n-3 ratios were 11:1 on the vegetarian diet, 15:1 on the white meat diet, 8:1 on the red meat diet, and 2:1 on the fish diet (P < 0.001). Neither white nor red meat diets affected platelet 20:4n-6 levels, platelet aggregation, ex vivo platelet TXB2 production, or the systemic PGI2 or TXA2 production as measured by gas chromatography-mass spectrometry analysis of the excretion levels of the principal urinary metabolites 2,3-dinor-6-keto-PGF1 alpha (PGI2-M) and 11-dehydro-TXB2 (TXA2-M), respectively. The fish diet decreased the 20:4n-6/20:5n-3 ratio in platelet PL from the baseline level of 45:1 to 13:1 (P < 0.001), had no effects on platelet aggregation, but significantly decreased platelet TXB2 production (collagen-stimulated) and TXA2-M production, while PGI2-M levels were unaltered. These results indicate that short-term diets which double the usual 20:4n-6 intake using white meat (175-330 g/d) or red meat (275-530 g/d) are not associated with an increased TXA2 production, but this does not rule out the adverse effects of 20:4n-6 at higher levels in the diet, or for more prolonged periods. Short-term diets containing fish (100-200 g/d with 90-210 mg/d 20:4n-6 and approximately 650-1000 mg/d 20:5n-3) led to significant increases in platelet 20:5n-3 levels and a decrease in the ex vivo and systemic TXA2 production.

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The three mono substituted N-[(E)-3-(4-hydroxyphenyl)prop-2-enoyl]spermidines1-3 have been studied by positive-ion electrospray-ionization tandem mass spectrometry (ESI-MS/MS). Because of the neighboring-group participation, the MS/MS of [l + H]+ and [2 + HIf are essentially similar, while compound 3 can be easily distinguished from 1 and 2 because of the characteristic ions at m / z 218. However, with the source collisioninduced dissociation (source-CID) MS/MS technique, the compounds 1 and 2 can be unambiguously distinguished by the signal of the pyrrolidinium ion (m/z 72) from their daughter ion ( m / z 275). The source-CID MS/MS of the labeled compound N-(4 -aminobutyl)-N-(3-aminopropyl)-N-[3-(4-hydroxyphenyi)prop-2-en['SN]amide] (["N(4)]-2) provide more information on the decomposition mechanisms and proved the occurrence of a partial transamidation reaction 2 -1 during the measurement Introduction. -The remarkable increase in information on the biochemical properties of polyamines and the awareness that inhibition of the enzymes involved in their biochemical pathways leads to valuable pharmacological agents, making these compounds important tools for the organic chemists [2]. Although the sporadic identification of the derivatives formed from the reaction of amines and 3-(4-hydroxyphenyl)prop-2-enoic acid ( = 4-hydroxycinnamic acid) in various plants has been reported for many years, it is only recently that the widespread nature and potential significance of these amides has been recognized [3] [4]. Since polyamine derivatives often appear as inseparable mixtures of minute amounts, electrospray-ionization mass spectrometry (ESI-MS) is generally used to investigate this class of compounds, especially due to the possibility of the on-line coupling with a HPLC system [5-71. To fully benefit from the potential of tandem mass spectrometry, it is important to comprehend the fragmentation mechanism of compounds under investigation, when this technique is used. Furthermore, informations on the decomposition reactions can be achieved by the application of the source-CID MS/MS technique [8] [9]. Herein, a MS/MS of the compound is produced in the ion source, and the thus generated ions can be further investigated by usual MS/MS analysis. Recently, the synthesis of all seven (E)-N-[3-(4-hydroxyphenyl)prop-2-enoyI]spermidines has been accomplished [lo]. The aim of this investigation is the mass-spectral identification of these compounds (for the mass-spectral behavior of the corresponding N,N-bis-(4-hydroxycinnamoyl)spermidines, see [ 1 11).

The current analytical methods for the various prostanoids require a separate and extended sample workup, derivatization, and gas chromatographic/mass spectrometric detection of each compound. Therefore, we developed and validated a rapid method for the common purification, derivatization, and GC/MS determination of 11-dehydrothromboxane B2, 2,3-dinor-6-keto-PGF1a, PGF2A, PGE2, PGD2, and isoprostanes in urine. A single reversed-phase solid-phase extraction step and modified reaction conditions yielded excellent sample purification at high recoveries and efficient derivatization for all compounds in one vial. The method allows, for the first time, the simultaneous quantification of these index metabolites of systemic thromboxane and prostacyclin synthesis, renal prostaglandin formation, and nonenzymatic in vivo lipid peroxidation in a single GC/MS run with high sensitivity and precision.

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