A triacylglycerol analogue, rac-1,2-di-O-oleoyl-3-S-oleoyl-3-thioglycerol, was fed to rats and chyle acylglycerols were analyzed. Triacylglycerol was the dominating chyle lipid but X-triacyl-1-thioglycerol constituted approx. 6% of total chyle lipids. Its identity was verified by ultraviolet and mass spectra and its stereochemical structure by ORD and CD. The proportions of triacyl-1-thio-sn-glycerol/triacyl-3-thio-sn-glycerol were 63/37 and 78/22 in two experiments. Possible reasons for this stereospecificity are discussed. The study shows that the stereochemical configuration of lipids isolated from biological material can be assessed by ORD and CD.

Animals↗

PubMedDate not supplied

Selenoprotein P in patients on home parenteral nutrition.

BACKGROUND: The purpose of this study was to evaluate the use of selenoprotein P as an indicator of selenium status in patients receiving home parenteral nutrition. METHODS: Adult patients (n = 38) who had been on parenteral nutrition with no addition of selenium for 3 to 216 months were included in the study. Plasma samples were analyzed for selenium, selenoprotein P, and extracellular glutathione peroxidase (eGSHPx) using fluorimetry and newly developed radioimmunoassays. RESULTS: The mean plasma (+/- SD) eGSHPx and selenoprotein P in the patients were 1.9 +/- 1.2 mg/L and 0.7 +/- 0.4 arbitrary units, respectively, which corresponds to about 50% of the concentration measured in the plasma of the reference subjects (4.0 +/- 1.0 mg/L and 1.50 +/- 0.17 arbitrary units). The mean plasma selenium concentration was 0.5 +/- 0.4 mumol/L, which was approximately half of the concentration measured in the healthy subjects (1.1 +/- 0.2 mumol/L). Thirty-four (89%) and 20 (53%) patients, respectively, had selenoprotein P and eGSHPx values lower than mean - 2 SD of the reference material. The lowest values observed for selenoprotein P and eGSHPx were 3% and 2% of the reference mean. Selenoprotein P levels correlated significantly to eGSHPx (p = 0.88, p < .0001) and plasma selenium (p = 0.91, p < .0001). CONCLUSIONS: The positive correlations between selenoprotein P and eGSHPX and plasma selenium indicates that selenoprotein P may be used as a marker of selenium status in selenium-depleted patients.

Aged↗

PubMedDate not supplied

Alkaptonuria and ochronosis in three siblings. Ascorbic acid treatment monitored by urinary HGA excretion.

Patients with alkaptonuria lack homogentisate 1,2-dioxygenase leading to retention of homogentistic acid (HGA) in body fluids and eventually to tissue deposition of oxidation products, giving rise to the clinical picture of ochronosis. Ascorbic acid is a known inhibitor of the enzyme which catalyses the oxidation of homogentisic acid (HGA) to the polymer with affinity for collagen and was used in the treatment of three siblings with alkaptonuria. Ascorbic acid 500 mg bid was administered for 12 months. Two of the siblings tolerated the treatment, and in one the symptoms improved, whereas in the other they worsened. Plasma and urinary levels of HGA were monitored with a new HPLC method. Ascorbic acid is not effective in the treatment of symptomatic ochronosis.

Alkaptonuria↗