On the Ultrastructure of Mast Cells and Globule Leucocytes in the Common Bile Duct of Cattle Chronically Infected With Fasciola Hepatica

Abstract

Mast cells and globule leucocytes in the walls of the common bile ducts of seven uninfected slaughtered cows and of five cows chronically infected with Fasciola hepatica were studied by electron microscopy. The mast cells displayed numerous small intracytoplasmic granules, the matrixes of which were either strongly electron-opaque and homogeneous or less dense with a fine-granular ultrastructure. Unattached ribosomes were abundant in the cytoplasm of the cells. Many mast cells in the walls of chronically infected bile ducts were normal-looking while the cells in the subepithelial tissues often showed striking irregularities in the ultrastructure of the granules. Globule leucocytes were most numerous in the surface epithelium and were not connected by desmosomes to the epithelial cells. The nuclei of the globule leucocytes were similar to those in the mast cells except that indentations caused by the globules were more usually seen. The globules were considerably larger than the mast cell granules but bounded by similar agranular capsules. The matrix of most globules was dense and homogeneous while the other globules showed dense reticulate or lamellate structures. The relationship between the mast cell and globule leucocyte in the liver is briefly discussed with reference to recent reports on these cells in the intestinal wall.

Sammanfattning

Mastceller och globulära leukocyter i gallgångsväggen hos sju oinfekterade slaktkor och hos fern med kronisk infektion av Fasciola hepatica studerades elektronmikroskopiskt. Mastcellerna uppvisade ett stort antal små intracytoplasmatiska granula. Dessa granulas matrix var antigen mycket elektrontätt och homogent eller mindre elektrontätt, uppvisande en fingranulär ultrastruktur. Fria ribosomer förekom mycket rikligt i cytoplasman. I väggarna av kroniskt infekterade gallgångar var flera mastceller morfologiskt normala medan cellerna i den subepiteliala vävnaden ofta uppvisade höggradiga oregelbundheter i granulas ultrastruktur. Globulära leukocyter förekom mest i ytepitelet och var inte sammanbundna med epitelcellerna genom desmosomer. De globulära leukocyternas kärnor liknade mastcellernas kärnor med den skillnaden att globulära indentationer oftare förekom hos de först nämnda cellerna. Till storleken var globuli betydligt större an mastcellgranuli men omgivna av liknande agranulära membran. För det mesta var det globulära matrixet tätt och homogent, en del globuli uppvisade en tät reticulär eller lamellär struktur. Sambandet mellan mastceller och globulära leukocyter i levern diskuteras i korthet med beaktande av tidigare uppgifter om dessa celler i tarmväggen.