Zeitschrift fur klinische Chemie und klinische Biochemie最新文献

16 Patients with acute right-sided cardiac failure associated with a high pressure of the central venous system, exhibited a marked increase in glutamate dehydrogenase activity in serum. This increase was 40-fold higher than in patients with acute viral hepatitis. Histological examination of seven deceased patients revealed central necrosis within the liver lobule. This observation led us to determine glutamate dehydrogenase activity in microdissected peripheral and central portions from the unchanged liver lobule. A 1.7-fold higher glutamate dehydrogenase activity was found in the central part of the liver lobule than in the peripheral portion. The diagnostic significance of the glutamate dehydrogenase activity distribution along the cords of liver cells is discussed in view of liver diseases with central necrosis.

The fluorometric analysis of 5-hydroxy-indoleacetic acid by condensation with o-phthaldialdehyde has been modified by substituting a HCl-H2SO4 mixture at room temperature for hot concentrated HCl. The sensitivity of the method was increased by a factor of 2.7.

A combined adsorption-gel filtration technique has been developed for the quantitation of the cortisol-binding capacity of transcortin: Endogenous steroids are removed from plasma by adsorption on uncoated charcoal. Saturation of the "stripped" binding sites of transcortin is accomplished by equilibrating the sample with a definite amount of labeled cortisol of low specific activity (0.1 muCi/mug). Transcortin-bound [4-14C]cortisol is isolated by gel filtration over Sephadex G-50 at 4 degrees C and measured by liquid scintillation counting. The cortisol-binding capacity of transcortin is calculated directly on the basis of the known specific activity of cortisol. The modification described eliminates methodological disadvantages associated with the original gel filtration procedures, i.e. the possible interference of various endogenous steroids with cortisol binding to transcortin, and the necessity of fluorometric or colorimetric determination of protein-bound cortisol. The values of the cortisol-binding capacity of transcortin in plasma obteined by this simplified assay are in close agreement with results reported in the literature (mean +/- S.D.): healthy males 261 +/- 23 mug/l) of transcortin-bound cortisol (n = 13), healthy nonpregnant females 255 +/- 31 mug/l (n = 15), and pregnant females prior to delivery 560 +/- 82 mug/l (n = 12).

The influence of fluorocarbon FC 43 on the metabolism of oestrogens in the isolated perfused rat liver was investigated. In comparative once-through perfusions with FC 43 emulsion or albumin solution as perfusion medium, the clearance rates of oestrone and its metabolites were determined. In perfusions with FC 43, the clearance of oestrone was lower, and the metabolites formed in the liver were more concentrated in the outflowing medium than in perfusions without fluorocarbon. This can be explained by the high affinity, even of conjugated oestrogens, to FC 43, which is established by equilibrium dialysis and partition coefficient. The results presented here show that the fluorocarbon has a strong influence of its own on the metabolism of steroids in the isolated perfused liver. Therefore, this solvent should be avoided as medium when the metabolism of steroids is studied in perfusion experiments.

Assays for the determination of serum alpha-N-acetylglucosaminidase (EC 3.2.1.50) activity are described employing p-nitrophenyl-N-acetyl-alpha-D-glucosaminide, phenyl-N-acetyl-alpha-D-glucosaminide, and UDP-N-acetylglucosamine as substrates. A log normal distribution of the serum enzyme activity was found. The determination of serum alpha-N-acetylglucosaminidase activity proved to be a valuable tool for the recognition of homozygous and heterozygous carriers of the Sanfilippo B gene.

This review, based on the current literature, considers the practical aspects of steroid radioimmunoassays. The problems associated with the raising of specific antisera and their characterization are discussed. Features of assay design, reliability criteria and practicability of radioimmunoassays for steroids are considered.

A method for the estimation of dopamine beta-hydroxylase activity in human serum is described, based on a thin layer chromatographic separation of the substrate ([14C]tyramine) from the reaction product ([14C]octopamine). The basic properties of the human serum enzyme, investigated by this method are described.