Mass fragmentographic determination of cholecalciferol and 25-hydroxycholecalciferol in human serum

Summary The serum extracts were purified by column-, thin layer- and high pressure liquid chromatography. Deuterated cholecalciferol and deuterated 25-hydroxycholecalciferol were used as internal standards. The quantitative analysis was performed using GC-mass fragmentography technique of TMS-ethers.     

The site of 25-hydroxycholecalciferol stimulated protein synthesis in the rat kidney

Summary Autoradiographs of the kidneys of rachitic rats dosed in vivo with 250 pmoles 25-hydroxycholecaliferol (25-OHD₃) and³H-leucine showed increased grain counts in portions of proximal renal tubules. On incubation of kidney slices the synthesis of only 1 cytosol protein was found to be stimulated by the steroid. On disc gel electrophoresis it had the characteristics of renal calcium binding protein.     

The effect of vitamin D3 and 25-hydroxycholecalciferol on intestinal transport of calcium in vivo and in vitro

Zusammenfassung 8 Stunden nach Injektion von 25-Hydroxycholecalciferol bei rachitischen Ratten steigerte sich der Kalzium-Transport des Duodenum in vivo wie auch in vitro bedeutend. Während dieser Zeit war Vitamin D₃, wirkungslos. 24 h nach der Injektion stimulierten beide Verbindungen in ähnlichem Masse den Kalzium-Transport.     

Lag period of action of 25-hydroxycholecalciferol on bone collagen metabolism in vitamin D deficient rats

Zusammenfassung Nachweis, dass die Freisetzung von Hydroxyprolin bei Knochenfragmenten bereits 6 h nach i.v. Verabreichung von 2,5 g 25-Hydroxycalciferol signifikant erhöht war, während eine entsprechend zugeführte Dosis von Vitamin D₃ erst 13 h später deutlich wirkte.

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We thank Dr.E. Kodicek and Dr.E. M. Cruickshank of Dunn Nutritional Laboratory for help and criticism, and Mrs.J. Jobbágy for technical assistance.     

Synthetic and biological activity of 25R and 25S diastereoisomers of dihydroxy-25,26 cholecalciferol (25,25(OH)2D3)]

The separation of 5-cholestene-3 beta, 25 (RS), 25-triol 3,26-diacetate into the diastereoisomers 25R and 25S by means of high pressure liquid chromatography (HPLC) is described. Their absolute configuration cannot be yet established. The less polar diastereoisomer is arbitrarily called 25 zeta1 and the more polar one 25 zeta2. Bromination, dehydrobromination and ultraviolet irradiation conducted to 25 zeta1, 26(OH2D3 and 25 zeta2, 26(OH)2D3 respectively. Their biological activity is described.     

GLC determination of betahistine in serum

A gas chromatographic method was developed for the determination of betahistine in serum in the range of 0.6-6.0 microgram/ml.     

GLC determination of betahistine in serum

Summary A gas chromatographic method was developed for the determination of betahistine in serum in the range of 0.6–6.0 g/ml.     

Studies on the late-pre-beta-lipoprotein of human serum.

Very low density lipoprotein (VLDL) isolated from 3 healthy normolipidaemic subjects had a raised VLDL cholesterol to triglyceride ratio. The VLDL fractions gave 2 pre-beta-bands on agarose gel electrophoresis. Family study of the subjects appears to indicate sex linkage of this trait and a possible polygenic type of inheritance.     

Mass spectrometric determination of the amino acid sequence in cystine- and cysteine-containing peptides

, - , , S-- S- .     

Mass spectrometric determination of the amino acid sequence in arginine-containing peptides

aa, a-a a- a aa - aa a -a .     

Determination of rubidium in human serum

Field desorption mass spectrometry (FD-MS) combined with stable isotope dilution has been used to determine rubidium concentrations from human serum. Samples obtained from 110 healthy volunteers (50 males, 60 females) were examined. The rubidium concentrations found varied from 0.96 to 3.56 mumoles/l, the average value being 1.96 mumoles/l. The precision of the measurements within a batch was 0.8%. The time for 1 analysis, including sample preparation is about 30 min, the total sample consumption is 100-200 mul. The corresponding potassium concentrations were also determined from all these serum samples; a weak trend towards higher potassium levels with increasing rubidium concentration is found.     

Formation of anaphylatoxin in human serum

Zusammenfassung Es ist möglich, auch in menschlichem Serum eine Anaphylatoxinbildung (AT) durch Kontaktaktivierung oder Kobragift zu induzieren. Wegen der geringen Mengen, die entstehen, muss das wirksame Prinzip vor dem biologischen Nachweis angereichert werden. Menschliches AT verhält sich in allen untersuchten Eigenschaften wie AT aus anderen Plasmaarten. Es unterscheidet sich von dem darmkontrahierenden Spaltprodukt aus der menschlichen Komplementkomponente C3, das mithin nicht als AT angesprochen werden kann.