Möglichkeiten und Grenzen des Punkt-Treff-Verfahrens zur Bestimmung des Fettgehaltes im bioptischen Leberschnittpräparat

Zusammenfassung

Die zwischen dem chemisch bestimmten Triglyceridgehalt und dem stereologisch mit Hilfe des Punkt-Treff-Verfahrens geschätzten Verfettungsgrad in Leberpunktionszylindern bestehenden signifikanten Korrelationen werden eingehend geprüft, theoretisch begründet und in einer Formel mathematisch zusammengefaßt. Entwicklung einer Schätzformel, die es gestattet, aus den Punkt-Treff-Werten auf den tatsächlichen Triglyceridgehalt zu schließen.

Summary

Triglyceride content of 81 human liver biopsies, obtained at laparoscopy or by percutaneous needle puncture, was quantitatively measured by chemical means and expressed as a percentage of wet weight. Depending on the degree of fat infiltration, triglyceride concentration varied from 0,5–24%. The degree of fat infiltration was histologically estimated by the convential method of grading and by a morphometric point system basing on the Delesse principle, which states that the volume fractionV _i of a componenti in the tissue can be estimated by measuring the area fractionA _i of a random section occupied by transsections ofi; the results obtained by this method are expressed as percent. The chemically measured triglyceride content and histologically resp. stereologically estimated degree of fat infiltration were compared and correlated statistically. There was a significant correlation between triglyceride content and various histological and stereological estimates of fat infiltration; paraffin sections proved more reliable than frozen sections for estimating the degree of fat infiltration.

The correlation between the chemical triglyceride content and the results of estimating by the point system is a hyperbolic one, when expressed in mathematical terms. This hyperbolic function becomes quite clear considering the fact that weight percent was compared with volume percent. By means of mathematical transformations the correlation between the results of the chemical and the stereological method could be brought into a linear system; so it was possible to calculate single, partial and multiple correlation coefficients. Furthermore the relation between the lipid fractions of blood plasma, body weight, some laboratory data and the triglyceride content of the biopsies were examined. The only significant correlation was found between body weight and fat infiltration of the liver.

On the basis of the results obtained a formula was developed for calculating the chemical triglyceride content from the stereologically estimated values.