Peripheral giant cell granuloma. An immunohistochemical and ultrastructural study.

OBJECTIVE: To study the nature of multinucleated and mononuclear cells from peripheral giant cell granuloma (PGCG). MATERIALS AND METHODS: Formalin-fixed, paraffin-embedded sections of 40 cases of PGCG were immunohistochemically stained for vimentin, alpha I-antichymotrypsin, CD68, S-100 protein, lysozyme, leucocyte common antigen (LCA), factor VIII-related antigen and muscle cell actin. Six cases of PGCG were also studied by transmission electron microscopy. RESULTS: Vimentin, alpha I-antichymotrypsin and CD68 were expressed in both the mononuclear and multinucleated giant cells. Dendritic mononuclear cells, positive for S-100 protein, were noted in 67.5% of the lesions, whereas lysozyme and leucocyte common antigen were detected in occasional mononuclear cells. Ultrastructural examination showed mononuclear cells with signs of phagocytosis and sometimes interdigitations with similar cells. Others presented non-specific characteristics and the third type exhibited cytoplasmic processes and occasional Birbeck granules. Some multinucleated giant cells showed oval nuclei, abundant mitochondria and granular endoplasmic reticulum whereas others presented with irregular nuclei and a great number of cytoplasmic vacuoles. CONCLUSIONS: Immunohistochemical and ultrastructural results suggest that PGCGs of the jaws are composed mainly of cells of the mononuclear phagocyte system and that Langerhans cells are present in two thirds of the lesions.

Gestational protein restriction induces CA3 dendritic atrophy in dorsal hippocampal neurons but does not alter learning and memory performance in adult offspring

Studies have demonstrated that nutrient deficiency during pregnancy or in early postnatal life results in structural abnormalities in the offspring hippocampus and in cognitive impairment. In an attempt to analyze whether gestational protein restriction might induce learning and memory impairments associated with structural changes in the hippocampus, we carried out a detailed morphometric analysis of the hippocampus of male adult rats together with the behavioral characterization of these animals in the Morris water maze (MWM). Our results demonstrate that gestational protein restriction leads to a decrease in total basal dendritic length and in the number of intersections of CA3 pyramidal neurons whereas the cytoarchitecture of CA1 and dentate gyrus remained unchanged. Despite presenting significant structural rearrangements, we did not observe impairments in the MWM test. Considering the clear dissociation between the behavioral profile and the hippocampus neuronal changes, the functional significance of dendritic remodeling in fetal processing remains undisclosed. © 2012 ISDN.

Neonatal anoxia in rats: hippocampal cellular and subcellular changes related to cell death and spatial memory

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Oral chronic graft-versus-host disease: analysis of dendritic cells subpopulations

The graft-versus-host disease is the major cause of morbidity and mortality in patients who have undergone hematopoietic stem cell transplantation. Aiming at contributing to the understanding of the role of myeloid and plasmacytoid dendritic cells, and natural killer cells in chronic graft-versus-host disease, we examined biopsies of jugal mucosa of 26 patients with acute myeloid leukemia who had undergone allogenic hematopoietic stem cell transplantation. Half of these patients developed oral chronic graft-versus-host disease. Microscopic sections were immunohistochemically stained for anti-CD1a, anti-CD123 and anti-CD56. We calculated the number of immunostained cells in the corium per square millimeter and applied the Mann-Whitney test. Results showed a statistically significant increase of myeloid dendritic cells (CD1a+; p=0,02) and natural killer cells (CD56; p=0,04) in patients with oral chronic graft-versus-host disease. CD123 immunostaining showed no statistical difference between groups. It was concluded that myeloid dendritic cells and natural killer cells participate in the development of oral chronic graft-versus-host disease.