Mast cells have been studied in the mucosa and connective tissue of 28 biopsies of human duodenum. They were collected from individuals who for various reasons had to undergo upper intestinal endoscopy. Tissues were fixed in both standard formalin and a formalin-acetic acid (FA) fixative developed for visualization of mucosal mast cells. With both fixatives connective tissue mast cells (CTMC) were equally well recognized. Only with the FA fixative, an additional population of mast cells was observed both in the mucosa and the connective tissue. This population consisted of round cells, always smaller than CTMC, with a number of granules staining violet with toluidine blue. These mast cells comprised two cell types, differing in size, the larger being present in both the mucosa and the connective tissue, the smaller ones in a subepithelial position in the crypts of Lieberkühn and in the adjacent submucosa. It was suggested that this first mentioned additional population was similar to the mucosal mast cells (MMC) observed in rats and mice. The subepithelially located metachromatic cells differed in morphology from the globule leukocytes found in rats and mice. It was concluded that in the human duodenum a population of cells with MMC staining characteristics is present, which can only be visualized under special fixation conditions. Their further characterization and role in various disease conditions remains to be elucidated.
Newborn larvae (NBL) possess the "transformation potential" (TP) to induce the basophilic transformation of the muscle cell into the nurse cell and to create the nurse cell-muscle larva complex. For investigation as to whether TP is age-dependent, three groups of synchronous NBL (sNBL) were obtained at 1 h, 9 h, and 6 days of age, respectively, and were injected intramuscularly into mice. The TP was demonstrated to be high for both 1- and 9-h-old sNBL, but for 6-day-old sNBL, none was found. The earliest transformation of muscle cells was observed at 48 h postinfection (p.i.) in the first two groups of sNBL. Moreover, for 1-h-old sNBL the numbers of basophilically transformed muscle cells without larvae were 3-fold those of sNBL observed in histology sections. The results indicate that (1) due to the high TP observed in the 1-h-old sNBL group, NBL are born with TP; (2) the TP is lost by aging; and (3) the induction of the basophilic transformation of muscle cells is possible without direct contact between the muscle cell and NBL being required, as contact with released factor(s) alone may be enough.
The mast cell response in the mucosa and connective tissue of 36 jejunal biopsies of patients with clinically diagnosed trichinellosis, teniasis and lambliasis has been studied. Biopsy material was fixed in standard formalin or Carnoy’s fixative, enabling differentiation between mucosal mast cells (MMC) and connective tissue mast cells (CTMC). With both fixatives CTMC could equally well be recognized. With Carnoy’s fixative an additional population of mast cells (MMC) could be visualized both in the mucosa and the connective tissue. In the mucosa small mucosal mast cells were observed as well. Compared to the numbers of mast cells in the mucosa and the connective tissue of teniasis and lambliasis patients, the number of mast cells in trichinellosis patients only visualized using Carnoy’s fixative was markedly higher. It was concluded that also in man trichinellosis is accompanied by an increase of cells with MMC characteristics. Further studies are needed to clarify the morphological and histochemical features of these cells and their possible role in this parasitic infection.
The present ultrastructure observations apply to the same experimental groups that were investigated in the first part of the study. The results of electron microscopy investigations correspond to those obtained using light microscopy methods. The ultrastructure data demonstrated that 1-h-old sNBL (group I) penetrated into the sarcoplasm of the muscle cells and transformed it basophilically, finally creating the "nurse cell-muscle larva complex." These larvae also caused transformation of the same muscle cells without being present in the sarcoplasm. The larvae of group II (9-h-old sNBL) preserved transformation potential as well, but it was less intensive. Not all NBL settled in the muscle cells; some of them remained in the intercellular spaces. Group II larvae present in the muscle cells underwent early degeneration and necrosis more often than did group I larvae; the inflammatory cell reactions in the vicinity of the larvae were more intensive. The basophilic transformation of muscle cells that did not contain larvae in their sarcoplasm was not intensive and often stopped at the level of cell nuclei. The larvae of group III (6-day-old sNBL) neither settled in the muscle cells nor transformed the cell sarcoplasm.
The aim of the present study was to determine the occurrence of eye infections accompanying the infection of the central nervous system and to demonstrate the possible tissue affinity of different strains of amoebae in subsequent infections. The results obtained demonstrate a clear correlation between the occurrence of eye infection and the degree of virulence of the strains. Amoebae isolated from eyeballs and other organs of dead mice did not exhibit any specificity in relation to the organs in subsequent infections. Irrespective of the place of isolation--be it eye or brain--in the subsequent passages, the amoebae were most often found in the brain and lungs, followed only then by the eye of the infected animals.
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