The ultrastructure of thè v. colica sinistra in a case of generalized vasomegaìy
in man was examined. Elastic material was found in three forms: as a lightly osmiophii
amorphous material bordering on myocytes, as a highly osmiophii elastic membrana,
and as highly osmiophii slim elastic fibres of different orientation in thè tunica media
and adventitia. The slightly osmiophii elastic material is assumed to be newly formed.
by pinocytotic activity of thè myocytes. The highly osmiophii elastic material indicatss
its impairment. No typical atherosclerotic changes were found in thè examined vein.
Based on a comparison with previous findings in thè case of vasomegaìy of thè
a. mesenterica inferior, thè authors conclude that thè venomegaly phenomenon is connected
with degenerative changes in thè elastic material of thè vessel wall