Production and properties of antiserum for radioimmunoassay of serum conjugated chenodeoxycholic acid and its preliminary application.

Sensitive tritiated radioimmunoassay was developed for conjugated chenodeoxycholic acid, using immunogen prepared by the mixed anhydride method. The obtained molar bile salt-BSA ratio in the immunogen was 19:1. The distinguishing features of the immunization procedure were a preliminary vaccination of the animal with antitubercular vaccine (VDS), and the administration of very small doses of immunogen (50 micrograms). Assay sensitivity for this bile salt fell in the picomole range with the standard curve extending from 1.5 to 150 pmol. Specificity of the antiserum was compared with that of the commercially available "Glycochenodeoxycholic acid RIA kit" (Nordiclab Oy, Oulu, Finland), and proved to be satisfactory. Fasting serum conjugated chenodeoxycholic acid concentration in 25 healthy subjects and 15 patients with cirrhosis was 0.63 mumol/l and 43.05 mumol/l, respectively. The assay was performed on unextracted sera.

Study of nucleic acid metabolism in two astronauts.

During the last years data have evidenced that alteration in nucleic acid metabolism, expecially increased urinary excretion of modified nucleosides reflects physiological changes in living organism. In relation with the Soyuz-36-Salyut-6-Soyuz-35 mission in 1980 urinary nucleoside excretion of two astronauts /B.F., V.K./ were traced. Individual daily urine samples were collected for 4 days before starting and 6 days after landing and were analysed with improved analytical procedures /affinity chromatography, high Performance liquid chromatography/. Levels of 1-methylinosine, 1-methylguanosine and N,2,2-dimethylguanosine in urine were determined. Thus recorded changes differ considerably at two astronauts. One of the /V.K./ excreted nucleosides normally, another /B.F./ showed increase to 200-400 % levels excretion of above nucleosides on the second day after landing. The peak values disappeared on the 3-6 days after. To interpret this phenomenon extreme factors of space-flight /weightlessness, stress, radiations, etc./ have to be taken into consideration. However, we attach importance to training of astronauts. During the last decade data have evidenced that alterations in the metabolism of nucleic acids especial increased urinary excretion of modified nucleosides reflects physiological and in some cases pathological changes in living organism. In relation with the Soyuz-36-Salyut-6-Soyuz 35 mission urinary excretion of certain modified nucleosides of two astronauts /B.F. and V.K./ were measured. The aim of the measurements was: how the metabolism of transfer ribonucleic acids /tRNAs/ referring to cosmic flight, how it is reflected in urinary excretions of modified nucleosides. For these purposes we studied the excretion of methylguanosine, dimethylguanosine and methylinosine. These nucleosides are the normal minor components of tRNA.