The ultrastructural examination of gingival fibromatosis.

Hereditary gingival fibromatosis (GF) is a special type of fibrous overgrowth classified as non-inflammatory gingival enlargement. Microscopically, the connective tissue consists of coarse collagen bundles and fibroblasts. The ultrastructural examination of fibrous gingival hyperplasia reveals that fibroblasts phagocyte the mast cell granules and mast cells stimulate collagen synthesis which results in hyperplasia. In the ultrastructural examination of phenytoin-induced hyperplasia, fibroblasts, phagocytosing mast cell granules were also found. Based on these findings, the purpose of this study is to establish whether there is a relationship between fibroblasts and mast cells in GF. The gingival tissues of 5 patients with GF were examined ultrastructurally. In the connective tissue, well-defined bundles of collagen fibres were found together with fibroblasts and capillaries. There were mast cells around these capillaries which had collapsed lumens. The proximity of the mast cells and fibroblasts may indicate that mast cells play some role on collagen synthesis of fibroblasts.

The effect of cyclosporin-A on the ultrastructure of gingival tissue in Behçet's disease.

Autoimmune processes are said to play an active role in aetiology of Behçet's disease (BD), which is also known as a multisystem disease. In the treatment of this autoimmune disease, cyclosporin A (CyA) is used. Gingival hyperplasia (GH) is one of the important side effects that have been observed in some of the patients. We aimed to evaluate the CyA-induced gingival hyperplasia in BD patients. There were 3 study groups, each having 5 patients. In the first group displaying GH, mast cells were located between epithelial cells and in the connective tissue. Mast cell granules were in crystalline form and electron-dense cored form. Fibroblasts and plasma cells were present in the connective tissue. The second group did not display GH and the mast cells were similar to those in the first group. The third group, was the control group, in which the mast cells were located between the epithelial cells and connective tissue. Mast cell granules were in electron-dense cored form. We concluded that the development of CyA-induced gingival hyperplasia is determined mainly by individual sensitivity to CyA, because although both test groups which received CyA showed an increased number and activity of fibroblasts, only one group of patients developed GH.

Mitochondria-lytic action of warfarin in lymphocytes.

Warfarin given as a single dose of 20 mg induces lysis of mitochondria in lymphocytes from chronic and acute lymphocytic leukemias studied under the electron microscope. Normal lymphocytes remain unchanged. This cytotoxic actin may be due to superoxide radicals produced in the malignant cells by warfarin, which is a potent electron-transferring substance.

Intestinal effects of iron deficiency anemia in children.

A group of 11 children with iron deficiency anemia were studied with respect to intestinal structure and function. In six cases there were histological abnormalities of intestinal mucosa in varying degrees consisting of villous damage, increased activity in the crypts, increased lymphoplasmocytic infiltration and changes in the surface epithelium. Ultrastructurally, microvilli lesions, mitochondrial changes and an increase in lysosomes were observed. Relative malabsorption of iron and d-xylose malabsorption were present in a minority of patients. Functional and structural changes were correlated. Our results suggest that these changes are due to impairment of cell metabolism.