Morphometry of terminal hepatic veins. 1. Comparative study in man and baboon.

In the present study, hepatic venous distribution per unit of liver surface area on normal wedge biopsies from man (n = 11) and baboon (n = 8) were analysed and compared. Terminal hepatic veins (THV - man: n = 100; baboon: n = 200) morphometric size variables were obtained with a Leitz ASM 68K morphometric equipment. THV, defined as hepatic veins up to 150 microns in internal diameter (ID), in the centrolobular position and with sinusoidal openings, represented 84% and 74% of hepatic veins of man and baboon, respectively. Four or more THV were generally found on 8 mm2 of liver surface. Transversely sectioned THV selected by the ratio IDminimum/IDmaximum greater than 0.67, was found to be only 25% of the total THV. In baboon, THV merge with other terminal veins and the interlobular veins present sinusoidal inlets. The baboon THV wall surface (WS) and wall thickness (WT) values were higher than in man. Positive correlations between the number of mesenchymal cells (Mc) in the vein wall and wall surface of terminal hepatic veins (man: r = 0.79; baboon: r = 0.83) and between wall surface and internal surface (IS) (man: r = 0.80; baboon: r = 0.72) were found. Two ratios were selected as the most reliable parameters: (1) for the THV wall rim, wall surface/internal surface (WS/IS - man: 0.43 +/- 0.16; baboon: 0.63 +/- 0.23), regarding transversely sectioned THV; and (2) for the evaluation of wall cell density (WS/Mc-man: 550 +/- 231; baboon: 558 +/- 183 micron 2/cell) as they did not depend on THV caliber.