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Biomedical subjects

J De Groote

Publications and source records attributed to J De Groote.

At least 73 records · Page 4Linked to original sources
PubMed1974

Unconjugated hyperbilirubinaemia in achalasia.

Moderate unconjugated hyperbilirubinaemia decreasing after pneumatic dilatation of the gastrooesophageal sphincter, so permitting a normal amount of food to be taken was observed in two patients with achalasia. Liver biopsy was performed, and hepatic digitonin-activated bilirubin UDP-glucuronyltransferase activity was decreased in both, as is usually found in patients with Gilbert's syndrome. In the patients examined the slight and variable hyperbilirubinaemia associated with Gilbert's syndrome seemed thus to have been aggravated because of the decreased food intake due to achalasia. This situation may be compared to the jaundice sometimes found in neonates with pyloric stenosis or other types of obstruction of the upper gastrointestinal tract. Observations in rats and man favour a complex mechanism for fasting-induced hyperbilirubinaemia.

Adult↗
PubMed1972

Bilirubin conjugates in bile of man and rat in the normal state and in liver disease.

Conjugates of bilirubin were studied in normal bile of man and rat, and in bile of liver patients. In general human bile was obtained by duodenal intubation. In addition T-tube bile was examined in patients operated on for mechanical obstruction. The bile pigment compositions of duodenal and T-tube bile were similar in two patients where comparison was possible. Obstruction of the bile duct in rats was used as an animal model for obstructive jaundice. Diazotized ethyl anthranilate was used for determination of total conjugated bile pigment and for thin-layer chromatography (t.l.c.) analysis of the derived azopigments. The available t.l.c. procedures are versatile and allow rapid and quantitative analysis. A variety of conjugated azopigments can be distinguished. With chloroform, negligible amounts of unconjugated bilirubin are extracted from bile of man. Therefore, the percentage of monoconjugated bile pigments present in the initial bile sample can be calculated from the percentage of azodipyrrole found after diazotization. Normal bile from man and rat yields similar azopigment patterns. The dominant component is azopigment-delta (azodipyrrole beta-D-monoglucuronoside). Small amounts of azopigments with complex conjugating structures (gamma-azopigments) are present in both cases. Human bile further yields small amounts of azopigments containing xylose or glucose (called azopigments-alpha(2) and -alpha(3), respectively). Monoconjugated bilirubin (estimated from the percentage of azodipyrrole) amounts of 22% of total bile pigments in human bile and to 39% in murine bile. In both, the bulk of bile pigment is bilirubin diglucuronoside. From bile of patients with acquired liver diseases a new azopigment group (beta-azopigment) was derived. The gamma-azopigment group was increased; the delta-azopigment group (containing azodipyrrole beta-D-monoglucuronoside) was decreased. No differentiation was possible between intra- and extrahepatic cholestasis. The percentage of beta-azopigment showed a positive correlation with serum bilirubin concentration (r = 0.6). Recovery of the diseases was accompanied by normalization of the azopigment patterns. In rats, hydrostatic or mechanical obstruction induced increases in beta- and gamma-azopigments and a decrease in delta-azopigment similar to the changes observed in bile of liver patients. Complete normalization was obtained 6 hr after relieving the hydrostatic obstruction (duration 15-21 hr). In contrast, with man after surgery for extrahepatic obstruction, T-tube bile was not normalized when the T-tube was withdrawn (10 days after operation). Hydrostatic obstruction in rats provides an easy model when postobstructive bile pigment composition and parameters have to be investigated. The present investigations stress the importance of the physiopathological state when studying bilirubin conjugation. Hindrance to bile secretion induced heterogeneity of bilirubin conjugates and stimulated the formation of complex structures.

Animals↗
PubMed1970

A clinical and histochemical study of cholestasis.

A histochemical study of conjugated and total bilirubin was made on liver biopsies of 150 patients. Three types of cholestasis were defined: type I, characterized by the presence of intracellular pigment granules in the hepatocytes; type II, showing intracellular granules and extracellular thrombi (this group may be subdivided according to the eventual presence of coarse pigment deposits in the parenchymal cells); and type III, showing intracellular granules, extracellular thrombi, and also bile pigment in the Kupffer cells. The fine liver cell granules correspond mainly to conjugated bilirubin, whereas the coarse deposits usually contain unconjugated pigment. The extracellular thrombi mostly contain conjugated bilirubin; the Kupffer cell pigment is predominantly of the unconjugated type. In cholestasis types II and III a diffuse directly reacting pigment is also observed. The finding of unconjugated pigment in different locations and the eventual deconjugation by beta-glucuronidase is discussed. A correlation was found between the different types of cholestasis, the level of bilirubinaemia, and its dynamic evolution. This suggests that the proposed types of cholestasis may represent successive stages of increasing cholestasis. The type of cholestasis and the nature of the pigment are largely independent of the aetiology. It is shown that a large percentage of minor degrees of cholestasis is missed when only conventional histological methods are used. The mechanisms by which morphological cholestasis is brought about are discussed in the light of the present findings.

Bilirubin↗