Stability of fat-soluble and water-soluble vitamins in artificially prepared, vitamin-enriched, lyophilized serum.

Vitamin-enriched, lyophilized serum (VES) was prepared for an inter-laboratory study to compare vitamin assays. The VES contained water-soluble vitamins (vitamin B1, vitamin B12, vitamin C, and folate), fat-soluble vitamins (vitamin A and vitamin E), and cholesterol. We performed stability studies and determined vitamin concentrations and total cholesterol in VES stored at -20 degrees C for 12 months. Our recovery of the water-soluble vitamins in reconstituted VES was 70-142%, but we recovered only 33-45% of the fat-soluble vitamins. Physicochemical properties, such as specific gravity and viscosity of the reconstituted VES did not affect manual or automated measurements of these vitamins. Vial-to-vial differences found for the VES were the same as the within-day analytical variations. There was no evidence of degradation of vitamin A, vitamin B1, vitamin B12, vitamin C, folate, and cholesterol over 12 months in VES stored at -20 degrees C. Following deproteinization, vitamin C concentration was found to be lower than when not deproteinated. Vitamin E was less stable in VES, however, and the degradation during 12 months was lower than the between-day analytical variation of the assay. Our VES is the first preparation of lyophilized control serum that contains water-soluble and fat-soluble vitamins.

Newly identified steroid hormone in urine of patients with Cushing's syndrome: 3alpha,11 beta-dihydroxy-4-androsten-17-one.

We have previously reported that the urine of patients with Cushing's syndrome, including pituitary adenoma cases and adrenal adenoma cases, consistently show a conspicuous peak in the chromatographical analysis of 17-ketosteroid fraction but not in the urine of control subjects. The substance emerges just before 11beta-hydroxy-androsterone (11beta-OH-A) in capillary gas chromatography. In the present study, we have identified an "unknown peak substance" observed in the urine of Cushing's syndrome patients using gas chromatography-mass spectrometry (GC/MS). Trimethylsilylether (TMS)-derivative of the substance was found to have a molecular weight (MW) of 448, which is similar to that of 11-OH-A (MW: 450). From these findings, we hypothesized that the substance had the structure of a C-19 steroid with two hydroxyl groups at positions C-3 and C-11, one keto-group at C-17 and a double bond between C-4 and C-5 of the A ring. We hypothesized that the unknown peak substance was 3alpha,11beta-dihydroxy-4-androsten-17-one (3alpha,11beta-DH-A). To confirm this speculation we synthesized 3alpha,11beta-DH-A and compared the elution pattern of it with that of the "unknown peak substance" using GC and GC/MS. We found that both substances were indistinguishable by GC and GC/MS analysis. These results suggest that the unknown substance observed in the urine of patients with Cushing's syndrome is 3alpha,11beta-DH-A.