Ras P21 EXPRESSION IN NEPHROBLASTOMA GROUP TUMORS

Ras p21 expression in 30 cases of nephroblastoma and related tumors was evaluated by the immunoperoxidase method using monoclonal anti- ras p21 antibody (RAP-5) raised against a synthetic polypeptide fragment of ras p21. In normal renal tissue, the epithelial cells of convoluted and collecting tubules and arterial wall leiomyocytes were positively stained. In nephroblastoma tumors, some of the epithelial cells forming primitive tubular and glomerular-like structures in the nephroblastic-type tumors and the cells with including intimal features were positive. However, the epithelial cells in more differentiated glandular structures of epithelial-type tumors, the rhabdoid cells in rhabdoid tumors and the cells in congenital mesoblastic nephroma failed to show positive staining. Nephroblastic cells, stromal cells and sarcomatous cells were also negative.     

Genetic and stimulatory cell type requirements for inducing class I major histocompatibility complex alloantigen-specific in vivo cytotoxic T cell immunity

Current interpretation based on analytical in vitro works that actions of Ia antigens and accessory cells such as macrophages and dendritic cells are crucial for inducing cytotoxic T cell responses to class I major histocompatibility complex (MHC) alloantigens has been challenged by experiments performed in a newly developed system handling in vivo cytotoxic T cell immunity. We first characterized the transplantation immunity for second-set rejection of ascitic tumor allografts as principally induced by allogeneic stimulator cells via direct pathway, and as exclusively mediated by class I MHC alloantigen-specific in vivo cytotoxic T cell activity. By comparison of activities of limiting effective doses (10(4)-10(5) cells per mouse) of various stimulator cells in this defined system, we could demonstrate that genetic disparity at the D region of H-2 to the recipient is just enough for inducing the immunity, and presence of allogeneic or syngeneic Ia antigens in addition to H-2D alloantigens on stimulator cells does not give any premium effect. Further study revealed that allogeneic peritoneal cells rich in macrophages or glass-adherent spleen cells enriched for dendritic cells are not stronger stimulators than allogeneic adherent cell-depleted spleen cells and semi-allogeneic thymocytes. These results fit with the alternative concept that the physiological pathway inducing in vivo cytotoxic T cell immunity for graft rejection entirely depends on class I MHC antigens on live lymphocytes as self-supported stimulators, and does not crucially involve additional stimulator activities of Ia antigens and special accessory cell types, which must be in vivo concerned with induction of other types of transplantation immunity.     

Disseminated Atypical Mycobacteriosis

Two cases of disseminated infection caused by Mycobacterium intracellulare were reported and discussed. In the first case, the patient was a fifty-seven-year-old male who complained of general fatigue, weight loss, and fever. Biopsy of the right inguinal lymph nodes and the liver revealed infiltration by histiocytes engulfing many acid-fast bacilli. At autopsy an egg-sized abscess was found is the region of the right Iliac lymph nodes. Histological examination showed histiocytic infiltration in the abscess wall, neighboring lymph nodes, liver, and spleen. In the second case, the patient was a four-year-old boy, who had persistent fever and splenomegaly. Splenectomy was performed and histological examination of the spleen revealed multiple nodular infiltration by swollen histiocytes with many acid-fast bacilli in their cytoplasm. The bone marrow aspirates and liver tissue obtained in the necropsy also showed many histiocytes containing many acid-fast bacilli. The authors emphasized the importance of paying special attention to atypical mycobacteriosis in feverish patients having lesions with a proliferation of histiocytes.     

Exogenous antigens are processed through the endoplasmic reticulum-associated degradation (ERAD) in cross-presentation by dendritic cells

Antigen cross-presentation is critical in infectious and tumor immunity where cytotoxic T lymphocytes are induced by dendritic cells specifically equipped with cellular machineries to present exogenous antigens with major histocompatibility complex (MHC) class I molecules. To examine molecular mechanisms of antigen cross-presentation, we employed as a model system a murine dendritic cell line DC2.4 capable of presenting soluble antigens such as ovalbumin (OVA) with MHC class I. Here, we demonstrate that exogenously added OVA is accumulated in the endoplasmic reticulum (ER) and late endosomes followed by retrograde transport to the cytoplasm through the Sec61 transporter complexes, and that CHIP functions as an E3 ubiquitin-ligase for OVA degradation by proteasomes. This mechanism is essentially the same as that known as the ER-associated degradation (ERAD) in the quality control of secretary and membrane proteins.     

Age-related changes in gene expression patterns of matrix metalloproteinases and their collagenous substrates in mandibular condylar cartilage in rats

Matrix metalloproteinases (MMPs) have been implicated in physiological cartilage matrix remodelling as well as in pathological and invasive extracellular matrix remodelling of tissue. Age-related changes in the gene expression patterns of MMPs in mandibular condylar cartilages (MCCs) were analysed. We examined the gene expression patterns of Mmp-8 and -13 and their substrates, Col1a1, Col2a1 and Col10a1, in MCC of growing and ageing rats. Temporomandibular joints of male Wistar rats aged 4, 8, 16 and 32 weeks were subjected to in situ hybridization analysis. Histologically, MMCs showed characteristics of growth plate cartilage at ages 4 and 8 weeks, and more closely resembled articular cartilage thereafter. Mmp-8 was expressed in the cells in all cartilaginous cell layers at ages 4 and 8 weeks, and then was localized only in the mature cells at ages 16 and 32 weeks. Whereas Mmp-13 expression was limited to the lowermost hypertrophic chondrocytes in the growth stage, mature chondrocytes instead of hypertrophic chondrocytes expressed Mmp-13 in adult non-hypertrophic MCC. Because Mmp-8 and -13 expression overlapped with Col2a1 and Col10a1, chondrocytes could play a pivotal role in degradation as well as production of the cartilaginous matrix in MCC.     

Increase in oxidized NO products and reduction in oxidized glutathione in cerebrospinal fluid from patients with sporadic form of amyotrophic lateral sclerosis

To determine the role of free radical mechanisms in the pathogenesis of amyotrophic lateral sclerosis (ALS), cerebrospinal fluid concentrations of oxidized nitric oxide (NO) products (nitrite and nitrate) and reduced and oxidized forms of glutathione (GSH and GSSG, respectively) were compared between patients with the sporadic form of ALS (SALS) and controls. In the SALS patients, the nitrate levels were significantly higher (by 73%) in contrast to remarkably lower GSSG/GSH ratio, approximately 3-fold, compared to controls. These results suggest that NO production or oxidation is activated in SALS patients, leading to a decrease in superoxide radicals to oxidize GSH. The subsequent generation of a highly reactive anion, peroxynitrite, may play a causal role in the pathogenesis of SALS.     

Involvement of cAMP response element-binding protein activation in salivary secretion.

OBJECTIVE: Saliva secretion is mediated by cAMP and the calcium signaling pathway in salivary acinar cells. The PKA signaling pathway plays an important role in protein secretion through the activation of cAMP, in fluid secretion through the elevation of intracellular calcium and in the activation of cAMP response element-binding protein (CREB), which is involved in these signaling cascades. In this study, we investigated whether the activation of CREB plays a part in the salivary secretion in mice. METHODS: We examined CREB activation by assessing phosphorylation at the serine-133 position using Western blotting. RESULTS: Carbachol (a muscarinic acetylcholine agonist) and isoproterenol (a beta-adrenergic agonist) markedly activated CREB in parotid acinar cells. Carbachol and isoproterenol-induced CREB phosphorylation was blocked by atropine (a muscarinic acetylcholine antagonist) and propranolol (a beta-adrenergic antagonist), respectively. The PKA inhibitor H89 inhibited CREB activation, but the PLC inhibitor U73122 did not. Moreover, carbachol- and isoproterenol-stimulated amylase secretion from parotid acinar cells was inhibited by H89 and adenoviral dominant-negative CREB. CONCLUSION: These results indicate that the muscarinic and beta-adrenergic activation of CREB was mediated through the PKA pathway and that CREB is involved in protein secretion from parotid acinar cells.     

Balloon cell nevus of the soft palate: an immunohistochemical and ultrastructural study

An ultrastructural analysis of oral balloon cell nevus of intramucosal type complemented with an immunohistochemical study was performed for the first time. The lesion was composed of large balloon cells with an admixture of small nevus cells and melanophages at the periphery. Balloon cells showed cytoplasmic accumulation of vacuoles of varying sizes and the presence of microgranular and vacuolated melanosomes were found. Residual cytoplasm contained no identifiable organelles. A spectrum of transitional forms between balloon cells and conventional nevus cells with microvacuoles was readily observed. Both cells exhibited intense immunoreactivity to multiple melanocytic markers. Ballooning phenomenon was not evident in melanophages containing a large amount of melanosome complex. It can be inferred, from the present and previous observations, that progressive vacuolization of melanosomes in nevomelanocytes may be responsible for the formation of peculiar ballooning appearance, suggesting an aberrant melanogenesis.