Evaluation of a sensitive radioimmunoassay of plasma corticotropin using commercial reagents.

A radioimmunological method for the sensitive estimation of plasma corticotropin immunoreactivity (ACTH) using commercially available reagents is presented. The method involves silica extraction of corticotropin from plasma, desorption with acid protein solution, neutralization and subsequent radiomimmunoassay (RIA). [125I]corticotropin is added as internal standard to the plasma sample.

Specific and practicable assessment of urinary free cortisol by combination of automatic high-pressure liquid chromatography and radioimmunoassay.

An assay for the specific measurement of urinary free cortisol excretion is described. The method involves a simple solid-phase extraction, automatic high pressure liquid chromatography (HPLC) and radioimmunological quantification. The concurrent study on antigenically interfering compounds in the organic extract of urine revealed that non-specific immunoreactivities with a chromatographic behaviour very similar to cortisol are present in urine, which are not attributable to the steroids commonly studied for cross-reactivity.

Interferences in the radioimmunological determination of urinary free cortisol.

The magnitude of interferences arising in the radioimmunological assessment of urinary free cortisol is studied (a) by comparing cortisol immunoreactivities from crude urine, after organic solvent extraction of different selectivity and after additional chromatography by high pressure liquid chromatography (HPLC) and (b) by evaluation of the profile of immunoreactivity resulting from the fractions eluted by HPLC. Three antisera from different sources have been investigated. Values of cortisol-immunoreactivity in crude urine were about six times and values of a simple dichloromethane extract about three times higher than values obtained after HPLC.

Comparison of different high-performance liquid chromatographic systems for the purification of adrenal and gonadal steroids prior to immunoassay.

The high-performance liquid chromatography of nineteen hormonal steroids with special respect to its suitability for routine purification of these steroids from crude, organic extracts of biological fluids prior to final quantitation by immunoassay has been studied. In all systems the gradient elution technique was applied. Separation of steroids has been investigated using different stationary phases chemically coated with non-polar, hydroxyl, NO2 and CN groups.

Characteristics of transcriptionally active and inactive neuronal and nonastrocytic glial rat brain chromatin fractions.

Rapid and reliable fractionation of neuronal and nonastrocytic glial (NAG) cerebral rat brain chromatin in transcribable and repressed portions was achieved employing the DNAase II/Mg++-solubility method of Gottesfeld et al. (1974). Compositional and transcriptional properties of these fractions have been investigated.

[Influence of oxianthraquinones on the crystallization of calcium oxalate and calcium phosphate: dissolution of calciumcontaining urinary calculi (author's transl)].

Ruberythric acid and alizarin glucuronide, the biologic secretion product obtained from the alizarin derivative, stop the crystallization of calcium oxalate and calcium phosphate in the physiologic milieu of the urine. This effect is thought to be due to a soluble alizarin glucuronide: calcium chelate (2:1 mol). From this finding, we deduce that the solubility of calcium oxalate and calcium phosphate in the urine of humans can be increased through the oral administration of oxianthraquinone.

Studies on the regulation of RNA synthesis in neuronal and glial nuclei isolated from rat brain.

In searching for regulatory mechanisms involved in the cell-specific neuronal and glial transcription a cell-free transcriptional system has been developed using neuronal and glial rat brain chromatin and partially purified neuronal and glial nuclear rat brain RNA polymerases. Both free and chromatin-bound (engaged) neuronal and glial RNA polymerase fractions were separated from isolated neuronal and glial rat brain nuclei to determine their transcriptive efficiency. A double number of RNA initiation sites was measured on the neuronal when compared to the glial chromatin, independently of whether the neuronal or the glial RNA polymerase preparation was used for the determination.