Activated natural killer T cells producing interferon-gamma elicit promoting activity to murine dendritic cell-based autoimmune hepatic inflammation.

As natural killer (NK) T cells play an important role in the development of autoimmune diseases, they should have significant roles for the pathogenesis of autoimmune liver disease. Implication of the NK T cells in the generation of autoimmune-related hepatic inflammation was investigated using a novel mouse model. Immunization of mice with dendritic cells (DCs) loaded with hepatocyte-mimicking hepatocellular carcinoma cells (DC/Hepa1-6) induces cytotoxic T lymphocytes (CTL) capable of killing hepatocytes. Subsequent administration of interleukin (IL)-12, a potent interferon-gamma (IFN-γ) inducer, to the immunized mice generates autoimmune hepatic inflammation (AHI), as reported previously. Upon onset of the AHI response, the number of intrahepatic CD3(+) NK1 · 1(+) NK T cells increased markedly, along with a decrease in the number of splenic NK T cells, augmented expression of CXCR6 on intrahepatic NK T cells and CXCL16 in hepatic tissue, suggesting that NK T cells were recruited into the inflamed liver. The NK T cells were strongly positive for CD69 and produced IFN-γ, but not IL-4. AHI activity was attenuated markedly in CD1d(-/-) NK T cell-deficient mice, indicating that NK T cells play a pivotal role in the development of AHI. Mice treated with DC/Hepa1-6 and alpha-galactosylceramide, a potent NK T cell activator, also exhibited similar hepatic inflammation, in which activated NK T cells producing IFN-γ and CD8(+) T cells cytotoxic to hepatocytes were induced in liver-infiltrating mononuclear cells. Activated NK T cells producing IFN-γ potentiate DC-based AHI in the mouse model.

Pathological Features of Complete Atrioventricular Block in Dogs with Lymphocytic Myocarditis.

The cardiac conduction system was examined histologically in 12 canine cases of lymphocytic myocarditis with complete atrioventricular (AV) block. Histological analysis showed active myocarditis characterized by intense infiltration of mononuclear cells, primarily lymphoid, associated with degeneration and necrosis of the adjacent cardiomyocytes. Additionally, there was healing or healed myocarditis manifested by disappearance of cardiomyocytes and replacement fibrosis. This destructive inflammatory process of lymphocytic myocarditis involved the whole of the AV conduction system, resulting in loss and deletion of the conduction fibres, as well as the myocardium of all chambers. Such total or subtotal destruction of the AV conduction system caused by the inflammatory changes was thought to have set the stage for blocking AV conduction of cardiac impulses, but the aetiology of the lymphocytic myocarditis was not elucidated.

The distributive pattern, form and function seen in microvascular cast specimens of filiform papillae on the anterodorsal surface of the adult rat tongue.

The purpose of the present study was to examine in detail the distributive pattern, form and function of small conical papillae (SCP) and of filiform papillae (FIP) in the anterodorsal part of the adult rat fore-tongue in a microvascular cast specimen (MVCS), with the scanning electron microscope (SEM), and to elucidate the close relationship between the morphological characteristics and the function of the tongue. From the results obtained in this study, SCP in the anterior part were subdivided into three types: SCP type I, II and III according to the shape, size, distributive pattern and form taken from the two peripheral sides as for as the median sulcus (MS) in the central portion. The results we obtained suggested that the primary role of SCP types I and II at the apex may be mainly that of touch and attachment to the food and water, while SCP types II and III in the anterior part function efficiently by taking the food and water from both peripheral sides to the MS or central portion, and finally transporting it into the oral cavity and supporting the mastication system.