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Biomedical subjects

M Jirsa

Publications and source records attributed to M Jirsa.

At least 109 records · Page 6Linked to original sources
PubMed1982

Porphyrinogens in urine in various types of porphyrias.

Porphyrinogens were determined in very fresh, diluted morning urine in two types of hepatic porphyria, using a simple and very quick spectrophotometric method. It was shown that acidification by itself is insufficient for the complete conversion of colourless porphyrinogens into porphyrins in photometric determination of porphyrins in diluted urine. A correlation was shown between percentual content of porphyrinogens and the sum of pentacarboxyporphyrins and coprophyrin. A difference was found between the excretion of porphyrinogens in morning fresh urine in porphyria cutanea tarda (average porphyrinogen fraction 22.5%, SD 10.3% of total porphyrins) and in acute intermittent porphyria (average porphyrinogen fraction 77.1%, SD 9.3% of total porphyrins). The method is at the same time suitable for the detection of urobilinoids in urine. Oxidation of the urine in acute intermittent porphyria is recommended before absorption on talc and subsequent thin-layer chromatography, because porphyrinogens are not adsorbed on talc.

Adult↗
PubMed1982

Transformation of bilirubin in gastrointestinal tract and its relationship to neonatal icterus.

The object of the study was the transformation of bilirubin in the neonatal digestive tract with special reference to enterohepatic circulation of nonconjugated bilirubin and its consequences. The application of biochemical and chromatographic methods showed that bilirubin excreted by neonatal livers was qualitatively distinct from that excreted by adult livers. Already in the first meconium practically all bilirubin conjugated with glucuronic acid was hydrolyzed, which means ample availability of nonconjugated bilirubin for its reresorption by intestines. The enterohepatic circulation of nonconjugated bilirubin could indirectly be demonstrated by early elimination of nonconjugated bilirubin reservoir - meconium - from the digestive tract. This resulted in a significant reduction of bilirubinaemia. It could be shown that in newborns with hyperbilirubinaemia alterations of structure of bilirubin excreted into bile due to phototherapy occurred. This finding leads to an assumption that besides a favourable effect, apparently predominating in bilirubin degradation, phototherapy tends in an undesirable way to increase enteral reabsorption of nonconjugated bilirubin back in the circulation.

Bile↗