Iron-induced calcification in human aortic vascular smooth muscle cells through interleukin-24 (IL-24), with/without TNF-alpha.

In CKD patients, arteriosclerotic lesions, including calcification, can occur in vascular smooth muscle cells in a process called Moenckeberg's medial arteriosclerosis. Iron overload induces several complications, including the acceleration of arteriosclerosis. However, the relationship between Moenckeberg's arteriosclerosis in vascular smooth muscle cells and iron accumulation has remained unknown. We tested the accelerated effect of iron on calcification in cultured human aortic vascular smooth muscle cells (HASMCs). After establishment of this model, we performed a microarray analysis using mRNA from early stage culture HASMCs after iron stimulation with or without TNF-alpha stimulation. The role of interleukin-24 (IL-24) was confirmed from candidate genes that might contribute to calcification. HASMCs demonstrated calcification induced by iron and TNF-alpha. Calcification of HASMCs was synergistically enhanced by stimulation with both iron and TNF-alpha. In the early phase of calcification, microarray analysis revealed up-regulation of IL-24. Stimulation of HASMCs by IL-24 instead of iron induced calcification. The anti-IL-24 antibody reversed the effect of IL-24, supporting the important role of IL-24 in HASMCs calcification. In conclusion, iron-induced calcification in vascular smooth muscle cells occurred via IL-24, IL-24 was increased during the calcification process induced by iron, and IL-24 itself caused calcification in the absence of iron.

Expression of interleukin-34 and colony stimulating factor-1 in the stimulated periodontal ligament cells with tumor necrosis factor-α.

Tumor necrosis factor-α (TNF-α) directly and indirectly plays a crucial role in osteoclastogenesis. However, the indirect effects of TNF-α on colony-stimulating factor-1 receptor (CSF-1R)-mediated osteoclastogenesis achieved via periodontal ligament (PDL) cells are not fully understood. We herein examined the potency of osteoclast differentiation and maturation induced by fivefold supernatants in the stimulated human PDL cells with a physiologically high concentration (10 ng/mL) of recombinant TNF-α to human peripheral blood monocytes/macrophages in the simultaneous presence of the receptor activator of nuclear factor kappa-B ligand. The number of tartrate-resistant acid phosphatase-positive cells with multiple nuclei, but not those with a single nucleus, was decreased by approximately 50% by neutralization with rabbit IgG against either interleukin-34 (IL-34) or CSF-1. Small and large amounts of IL34 and CSF1 transcripts were measured in the stimulated PDL cells using real-time polymerase chain reaction. The corresponding amounts of proteins to IL34 and CSF1 transcripts were observed in the stimulated PDL cells on immunohistochemical staining or Western blotting. Moreover, 0.13 ng/mL of IL-34 and 5.0 ng/mL of CSF-1 were measured in the supernatants of the stimulated PDL cells using an enzyme-linked immunosorbent assay. IL-34 derived from the stimulated PDL cells with TNF-α appeared to synergistically function with CSF-1 in the CSF-1R-mediated maturation of osteoclastogenesis.

Cell-adhesion molecule expression and the proliferation of malignant mesothelioma: a post-mortem examination.

AIM: In order to determine if metastatic malignant mesothelioma cells are more aggressive than primary malignant mesothelioma cells, an analysis of the expression of the adhesion molecules E-cadherin and ß-catenin, concomitant with an assessment of the proliferative activity at primary and metastatic sites, was conducted in post-mortem samples. MATERIALS AND METHODS: E-cadherin or ß-catenin expression was graded according to the percentage of positively-stained tumor cells. The proliferative activity was quantified by the Ki-67 labeling index. RESULTS: Histologically, the majority of metastatic tumors matched the primary tumor. In the epithelioid component of primary tumors, E-cadherin and ß-catenin expression ranged from 1+ to 4+. CONCLUSION: Malignant mesothelioma cells acquire a higher proliferative potential after metastasis, without any significant changes in their histology, although metastasis produces no definite trend on the expression of E-cadherin or ß-catenin.

Estrogen decreases the expression of claudin-5 in vascular endothelial cells in the murine uterus.

Vascular endothelial (VE)-cadherin and claudin-5 are major components of the adherens and tight junctions of vascular endothelial cells, respectively, and decreases in their expression are associated with increases in endothelial paracellular permeability. In the uterus, estrogen induces endometrial edema. However, the in vivo effect of estrogen on endothelial paracellular permeability is unknown. Therefore, we studied the expression of VE-cadherin and claudin-5 in vascular endothelial cells in murine uteri stimulated by estrogen or progesterone. Ovariectomized mature mice were injected with estradiol-17ß (1 µg/mouse) or progesterone (1 mg/mouse) at intervals of 24 hours for 6 days. The frozen transverse sections of the uteri of these mice and untreated mice were stained for CD31 (vascular endothelial cell marker) plus VE-cadherin or claudin-5 using a double-immunofluorescence method. Then, the percentages of VE-cadherin- or claudin-5-positive vessels among CD31-positive vessels were examined in the uterine endometria. VE-cadherin and claudin-5 were expressed in most CD31-positive vessels in the endometria of the untreated mice. Progesterone did not affect the expression of both VE-cadherin and claudin-5 and estradiol-17ß also did not affect the VE-cadherin expression, but estradiol-17ß significantly decreased the claudin-5 expression. This decreasing effect of estradiol-17ß was detected from 24 hours later when the water content per a uterus significantly increased. The present study indicates that estrogen, but not progesterone, decreases the expression of claudin-5 in vascular endothelial cells in the murine uterine endometrium from 24 hours later, suggesting that the decrease in the claudin-5 expression contributes to the endometrial edema late after the estrogen stimulation.

Decreased expression of VE-cadherin and claudin-5 and increased phosphorylation of VE-cadherin in vascular endothelium in nasal polyps.

VE-cadherin and claudin-5 are major components of adherens and tight junctions of vascular endothelial cells and a decrease in their expression and an increase in the tyrosine-phosphorylation of VE-cadherin are associated with an increase in endothelial paracellular permeability. To clarify the mechanism underlying the development of edema in nasal polyps, we studied these molecules in polyp microvessels. Normal inferior turbinate mucosal tissues and nasal polyps from patients treated with or without glucocorticoid were stained for VE-cadherin or claudin-5 and CD31 by a double-immunofluorescence method and the immunofluorescence intensities were graded 1-3 with increasing intensity. To correct for differences in fluorescence intensity attributable to a different endothelial area being exposed in a section or to the thickness of a section, the relative immunofluorescence intensity was estimated by dividing the grade of VE-cadherin or claudin-5 by that of CD31 in each microvessel. Tyrosine-phosphorylation of VE-cadherin was examined by Western blot analysis. The relative intensities of VE-cadherin and claudin-5 in the CD31-positive microvessels significantly decreased in the following order; inferior turbinate mucosa, treated polyps and untreated polyps. The ratio of tyrosine-phosphorylated VE-cadherin to VE-cadherin was significantly higher in untreated polyps than in the inferior turbinate mucosa and treated polyps, between which no significant difference in the ratio was seen. Thus, in nasal polyps, the barrier function of endothelial adherens and tight junctions is weakened, although glucocorticoid treatment improves this weakened barrier function.

Hypoxia downregulates the expression of cell surface MICA without increasing soluble MICA in osteosarcoma cells in a HIF-1α-dependent manner.

Tumor cells express NKG2D ligands on their cell surface, which are the ligands of the activating receptor, NKG2D, that is expressed on the surface of NK cells. The binding of NK cells to tumor cells through the interaction of NKG2D and its ligands induces the cytolysis of the tumor cells. In the present study, we investigated the effects of hypoxia on the expression of NKG2D ligands on the surface of human osteosarcoma cells using three cell lines. To produce hypoxic and normoxic conditions, the osteosarcoma cell lines were cultured under 1 and 20% O2 conditions, respectively. The osteosarcoma cells expressed NKG2D ligands such as MHC class I-related chain molecules A and B (MICA and MICB) and the UL16-binding proteins 1, 2 and 3 (ULBP 1, 2 and 3). MICA was the most frequently expressed NKG2D ligand in the osteosarcoma cells. Hypoxia decreased the expression of cell surface MICA only without increasing the secretion of soluble MICA, which is produced by proteolytic cleavage of cell surface MICA. Hypoxia consistently decreased the susceptibility of the osteosarcoma cells to the cytotoxicity of the NK cells. Hypoxia induced the expression of hypoxia-inducible factor-1α (HIF-1α), and knockdown of the expression of HIF-1α using small interfering RNA increased the expression of cell surface MICA and concomitantly increased the level of soluble MICA. Hypoxia decreased the production of nitric oxide (NO) metabolites (nitrite and nitrate), thus, indicating a decreasing effect on NO production. However, a NO donor, NOC18, decreased the expression of cell surface MICA without any apparent effects on the expression of HIF-1α under both hypoxic and normoxic conditions. The present results indicate that hypoxia downregulates the expression of cell surface MICA without increasing the level of soluble MICA in a HIF-1α-dependent manner and suggest that the effects of hypoxia are not linked to the hypoxia-induced reduction of NO production.

Downregulation of matrix metalloproteinase-9 mRNA by valproic acid plays a role in inhibiting the shedding of MHC class I-related molecules A and B on the surface of human osteosarcoma cells.

Valproic acid, a histone deacetylase inhibitor, increases the expression of cell surface MHC class I-related chain molecules (MICs) A and B (MICA and B) in osteosarcoma cells and decreases their secretion of soluble MICA and MICB, which are produced by the proteolytic cleavage of cell surface MICs. Osteosarcoma cells have been reported to produce high levels of matrix metalloproteinase (MMP)-2 and -9. In this study, we investigated the involvement of MMP-2 and -9 in the inhibitory action of valproic acid (VPA) on the proteolytic cleavage of cell surface MICs using the U-2 OS and SaOS-2 osteosarcoma cell lines. VPA caused a marked decrease in the expression of MMP-9 mRNA in the U-2 OS and SaOS-2 cells and in the expression of MMP-2 mRNA in the U-2 OS cells, but only a slight decrease in the expression of MMP-2 mRNA in the SaOS-2 cells. The transfection of small interfering RNA (siRNA) for MMP-9 decreased the secretion of soluble MICA and MICB by both U-2 OS and SaOS-2 cells, but that of siRNA for MMP-2 did not. The present study therefore demonstrates that the downregulation of MMP-9 mRNA by VPA plays a role in the inhibitory action of VPA on the secretion of soluble MICA and MICB in osteosarcoma cells.

Valproic acid cooperates with hydralazine to augment the susceptibility of human osteosarcoma cells to Fas- and NK cell-mediated cell death.

We investigated the effects of valproic acid (VPA), a histone deacetylase inhibitor, in combination with hydralazine, a DNA methylation inhibitor, on the expression of cell-surface Fas and MHC-class I-related chain molecules A and B (MICA and B), the ligands of NKG2D which is an activating receptor of NK cells, and on production of their soluble forms in HOS, U-2 OS and SaOS-2 human osteosarcoma cell lines. We also examined the susceptibility of these cells to Fas- and NK cell-mediated cell death. VPA did not increase the expression of Fas on the surface of osteosarcoma cells, while hydralazine did, and the combination of VPA with hydralazine increased the expression of cell-surface Fas. In contrast, the combination of VPA with hydralazine did not increase the production of soluble Fas by osteosarcoma cells. Both VPA and hydralazine increased the expression of cell-surface MICA and B in osteosarcoma cells, and their combination induced a greater increase in their expression. VPA inhibited the production of both soluble MICA and MICB by osteosarcoma cells while hydralazine produced no effect. Both VPA and hydralazine enhanced the susceptibility of osteosarcoma cells to Fas- and NK cell-mediated cell death and the combination of VPA with hydralazine further enhanced the effects. The present results suggest that combined administration of VPA and hydrazine is valuable for enhancing the therapeutic effects of immunotherapy for osteosarcomas.

Expression of both hepatocellular carcinoma and cholangiocarcinoma phenotypes in hepatocellular carcinoma and cholangiocarcinoma components in combined hepatocellular and cholangiocarcinoma.

Expression of phenotype markers of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) in HCC and CC components of 20 combined hepatocellular and cholangiocarcinomas (CHCs) of the liver was investigated immunohistochemically. Both HCC and CC components of all CHCs expressed at least one of the CC phenotype markers [cytokeratin (CK)-7, CK-19, and carbohydrate (CA) 19-9]. HCC components in 90% of CHCs and CC components in 95% of CHCs expressed at least one of these CC phenotype markers in more than 40% of cancer cells. HCC components in all CHCs expressed at least one of the HCC phenotype markers [hepatocyte antigen (HA), α-fetoprotein (AFP), and canalicular carcinoembryonic antigen]. HCC components in 90% of CHCs and CC components in 75% of CHCs expressed HA, AFP, or both. HCC components in 75% of CHCs and CC components in 60% of CHCs expressed HA, AFP, or both in more than 10% of cancer cells. The present results show that both HCC and CC components of most of the CHCs expressed both HCC and CC phenotypes, supporting the hypothesis that CHC originates from a hepatic progenitor cell capable of differentiating into hepatocytes and cholangiocytes.

Adipocyte-macrophage interaction may mediate LPS-induced low-grade inflammation: potential link with metabolic complications.

Chronic low-grade infection has been suggested to be associated with metabolic disorder such as diabetes. However, the molecular mechanism underlying this important association is largely unknown. The only clue established so far is that many subjects exhibit elevated levels of C-reactive protein as measured by highly sensitive assay. Here, we hypothesized that adipocyte-macrophage interaction plays a key role in amplifying such low grade infection to the level of influencing metabolic disorders. The presence of macrophages in abdominal adipose tissues was investigated by immunohistochemistry. To see whether molecules associated with acute phase protein, LPS signaling, and persistent recruitment of monocytes, are produced at higher amounts in adipocytes co-cultured with macrophages stimulated with low concentration of LPS (1 ng/ml), we measured serum amyloid A (SAA), LPS binding protein (LBP), soluble CD14 (sCD14), and RANTES levels in culture supernatant of co-cultures. Lastly, we investigated in vivo effect of low-grade LPS infusion on the production of these molecules using obese model mice. The macrophages were certainly identified in abdominal adipose tissues. Investigated molecules, especially LBP, SAA, and RANTES were produced at higher amounts in co-cultures stimulated with LPS compared with the cells without LPS. The ob/ob, and high-fat diet-induced obesity mice produced higher amounts of LBP, SAA, and RANTES one day after LPS infusion (1 ng/ml/g body weight) compared with ob/- and normal-fat fed control mice. Thus, adipocytes and infiltrated macrophages, and their interaction with low endotoxin stimulation appear to play an important role in amplifying and maintaining LPS-induced low-grade inflammation.

Expression of hepatocyte markers in mass-forming peripheral and periductal-infiltrating hilar intrahepatic cholangiocarcinomas.

In this study, the expression of hepatocyte markers, including α-fetoprotein (AFP), HepPar-1 antigen and arginase-1, was examined immunohistochemically in 14 mass-forming peripheral intrahepatic cholangiocarcinomas (ICCs) that arose from the peripheral portion of the biliary tree, and in 14 periductal-infiltrating hilar ICCs that arose from intrahepatic large bile ducts. Only 2 (14.3%) of the 14 hilar ICCs and 2 (14.3%) of the 14 peripheral ICCs expressed AFP or HepPar-1 antigen. Conversely, arginase-1 was expressed in 8 (57.1%) and 11 (78.6%) of the hilar and peripheral ICCs, respectively, and 4 (28.6%) hilar ICCs and 7 (50%) peripheral ICCs expressed arginase-1 in more than 10% of the cancer cells. The expression of arginase-1 did not differ between peripheral ICCs showing major histology of poorly differentiated adenocarcinoma and those showing other major histologies, including well-or moderately differentiated tubular adenocarcinoma or papillary adenocarcinoma. Results of the present study showed that common hepatocyte markers, including AFP and HepPar-1 antigen, are rarely but definitely expressed in hilar and peripheral ICCs, and that a third hepatocyte marker, arginase-1, is expressed at a high rate in both hilar and peripheral ICCs, irrespective of their histology. These results indicate that care should be taken when using arginase-1 as a hepatocyte marker for distinguishing between a poorly differentiated hepatocellular carcinoma and a mass-forming peripheral ICC showing the histology of poorly differentiated adenocarcinoma.

Sodium valproate, a histone deacetylase inhibitor, augments the expression of cell-surface NKG2D ligands, MICA/B, without increasing their soluble forms to enhance susceptibility of human osteosarcoma cells to NK cell-mediated cytotoxicity.

MHC class I-related chain molecules A and B (MICA and B) expressed on the cell-surface of tumor cells are ligands for an activating receptor, NKG2D, expressed on natural killer (NK) cells and stimulate the NK cell-mediated cytotoxicity. On the other hand, the soluble form of MICA and B produced by proteolytic cleavage of cell-surface MIC interferes with NK cell-mediated cytotoxicity. We investigated effect of sodium valproate (VPA), a histone deacetylase inhibitor, on the production of cell-surface and soluble MICA and B and NK cell-mediated cytotoxicity in four human osteosarcoma cells. VPA at 0.5 and 1.0 mM induced acetylation of histones bound to MICA and B gene promoters, increased cell-surface but not soluble MICA and B, and augmented the susceptibility of osteosarcoma cells to NK cell-mediated cytotoxicity. The present results indicate that VPA sensitizes human osteosarcoma cells to cytotoxicity of NK cells.

Immunohistochemical analyses of E-cadherin, beta-catenin, CD44s, and CD44v6 expressions, and Ki-67 labeling index in intraductal papillary mucinous neoplasms of the pancreas and associated invasive carcinomas.

We examined the expressions of adhesion molecules (E-cadherin, beta-catenin, CD44s, and CD44v6) and Ki-67 labeling index (Ki-67 LI) in low- and moderate-grade dysplasia and invasive carcinoma components in ten noninvasive intraductal papillary mucinous neoplasms (IPMNs) of the pancreas and eight invasive carcinomas associated with IPMNs of the pancreas using immunohistochemical methods. There was no significant difference in regard to the proportion of components expressing either E-cadherin or beta-catenin in more than 70% of the tumor cells between the low- and moderate-grade dysplasia components. In contrast, the proportion of those in invasive carcinoma components was significantly lower than in low- or moderate-grade dysplasia components. Also, there was no significant difference in the proportion of components expressing CD44s or CD44v6 in more than 5% of tumor cells among low-grade dysplasia, moderate-grade dysplasia, and invasive carcinoma components. In contrast, the Ki-67 LI values increased in the order of low-grade dysplasia, moderate-grade dysplasia, and invasive carcinoma components, with significant differences among them. The present results indicate that carcinoma components are associated with a decrease in tumor cells expressing E-cadherin and beta-catenin and have the highest proliferative activity.

Immunotherapy with interleukin-18 in combination with preoperative chemotherapy with ifosfamide effectively inhibits postoperative progression of pulmonary metastases in a mouse osteosarcoma model.

The effect of immunotherapy with interleukin-18 (IL-18) in combination with preoperative chemotherapy on the postoperative progression of pulmonary metastasis was examined using a spontaneous pulmonary metastasis model of mouse osteosarcoma. Mice were inoculated subcutaneously with highly metastatic murine osteosarcoma cells (LM8) and then underwent chemotherapy with ifosfamide (30 or 60 mg/kg body weight, days 14-16), immunotherapy with IL-18 (2 microg/mouse, days 18-24) or combined immunotherapy and chemotherapy. Tumors developed in mice were excised 21 days after cell inoculation when microscopic but not macroscopic pulmonary metastasis was observed in mice. Three weeks after the excision of the tumors, macroscopic pulmonary metastasis was observed on the surface of the lung. Administration of ifosfamide or IL-18 alone decreased the number of macroscopic pulmonary metastases, and combined administration of ifosfamide and IL-18 resulted in much greater inhibition of pulmonary metastasis. These results suggest that immunotherapy in combination with preoperative chemotherapy is highly effective in suppressing postoperative progression of pulmonary metastasis.

Sodium valproate, a histone deacetylase inhibitor, decreases the secretion of soluble Fas by human osteosarcoma cells and increases their sensitivity to Fas-mediated cell death.

PURPOSE: Effects of valproic acid (VPA), a histone deacetylase inhibitor, on the susceptibility to cell death induced by agonistic anti-Fas antibody were examined using four human osteosarcoma cell lines. METHOD: Cell growth, secretion of soluble Fas, expression of cell-surface Fas, and sensitivity to Fas-mediated cell death were examined using cell proliferation assay, flow cytometry, enzyme-linked immunosorbent assay, and agonistic anti-Fas antibody, respectively. RESULTS: VPA suppressed the growth of all the four osteosarcoma cell lines and the secretion of soluble Fas from these cells. VPA showed no or slight suppressive effect on the expression of cell-surface Fas in the four osteosarcoma cell lines, but increased the sensitivity of three of four osteosarcoma cell lines to Fas-mediated cell death. CONCLUSION: VPA enhances the susceptibility of human osteosarcoma cells to Fas-ligand-induced cell death by decreasing the secretion of soluble Fas and increasing the sensitivity to Fas-mediated cell death.

Transdifferentiation into biliary ductular cells of hepatocytes transplanted into the spleen.

AIMS: Transplantation of rat hepatocytes into the syngeneic rat spleen results in the appearance of cytokeratin (CK)7 and CK19 positive biliary cells that form ductules. We examined whether hepatocytes are the origin of these biliary ductular cells. METHODS: We transplanted rat dipeptidyl peptidase IV (DPPIV) positive hepatocytes into the liver of retrorsine-treated and partially hepatectomised DPPIV negative rats, which resulted in proliferation of DPPIV positive hepatocytes in the liver. Two months later, hepatocytes were prepared from chimaeric livers of these rats and transplanted into the spleen of DPPIV negative rats. Four weeks later, the expression of DPPIV in CK7 positive ductules in the spleen was examined by immunofluorescent double-staining. RESULTS: In the spleen of DPPIV negative rats transplanted with hepatocytes prepared from the chimaeric livers, DPPIV was found to be expressed in some CK7 positive biliary ductules where only a fraction of cells expressed DPPIV, whereas in the spleen of DPPIV negative rats transplanted with hepatocytes from livers of DPPIV positive rats, DPPIV was expressed in all CK7 positive biliary ductules. CONCLUSION: The present study indicates that hepatocytes transplanted into the spleen could transdifferentiate into biliary cells that aggregate to form ductular structures.

Enhanced suppression of pulmonary metastasis of malignant melanoma cells by combined administration of alpha-galactosylceramide and interleukin-18.

alpha-Galactosylceramide (alpha-GalCer) shows antitumor effects by activating natural killer (NK) cells indirectly through stimulation of the secretion of cytokines by NKT cells, whereas interleukin (IL)-18 shows antitumor effects by activating NK cells directly. In the present study, we examined the antitumor effect of the combined administration of alpha-GalCer and IL-18. An injection of NK cell-sensitive mouse B16 melanoma cells into a mouse tail vein produced pulmonary metastasis. The daily administration of alpha-GalCer or IL-18 alone for 4 days starting 1 day after the injection of B16 melanoma cells markedly suppressed the number of pulmonary metastatic foci, and their combined administration enhanced the antitumor effect compared with single administration. The antitumor effect of their combined administration was completely abolished by treatment of mice with anti-asialo GM1 serum, which depletes NK cells but not NKT cells. Combined administration of alpha-GalCer and IL-18 enhanced the cytotoxicity of NK cells and increased the number of NK cells in the lung. Analysis of NKT cell-dependent and NK cell-independent secretion of cytokines, to which NK cells can respond, showed that the administration of alpha-GalCer increased the secretion of IL-2, IL-4, interferon-gamma, IL-12, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-alpha, and IL-10, and the combined administration of alpha-GalCer and IL-18 enhanced the secretion of IL-2, IL-4, interferon-gamma, and granulocyte-macrophage colony-stimulating factor further but only slightly. These results show that IL-18 in combination with alpha-GalCer exerts an antitumor effect on NK cell-sensitive tumors primarily by the direct stimulation of NK cells by IL-18 and the indirect stimulation of NK cells by alpha-GalCer through its activation of NKT cells.

Epithelial-myoepithelial carcinoma arising in the nasal cavity.

This study documents a case of an epithelial-myoepithelial carcinoma (EMC) in the left nasal cavity. A 70-year-old woman who presented with recurrent epistaxis of the left nasal nostril of 3 months duration was found to have a polypoid tumor in the left nasal cavity. A computed tomography (CT) scan revealed a tumor to occupy the left inferior and middle nasal cavity which had destroyed the inferior nasal turbinate, and a horizontal scan showed the tumor to occupy the middle and posterior nasal cavity. Since the tumor was connected to the lateral wall of the left nasal cavity with a narrow stalk, the tumor was excised by peeling the mucosa from the wall of the left nasal cavity. Based on the histological and immunohistochemical findings, the tumor was diagnosed to be an EMC. The follow-up at 12 months after the operation showed no evidence of recurrence.

Histochemical demonstration of aluminum and iron deposition in pulmonary bony tissues in three cases of diffuse pulmonary ossification.

Diffuse pulmonary ossification is a rare condition. We examined three cases of it in Japan, and attempted histochemically to stain for deposition of aluminum and iron in bony tissues. The patients were all female, and in their mid-twenties, mid- eighties, and later teen years. One of the patients had been exposed to heavy metals in her work involving heavy-metal analyses for 18 months. Aluminum staining and Berlin blue staining for iron were performed with dewaxed, undecalcified sections of pulmonary tissues from these three cases. Interestingly, all pulmonary bony tissues from the three cases examined exhibited linear regions of both aluminum and iron deposition in the calcifying fronts or the cement lines of bones. The patient exposed to heavy metals exhibited the most severe aluminum and iron deposition, and also exhibited positive reaction for both aluminum and iron in elastic fibers of blood vessels. Foreign body granulomas with multinucleated giant cells exhibiting elastophagia were also found in this case. This phenomenon, "endogenous pneumoconiosis", appeared to have been the cause of pulmonary hemorrhage in this case, resulting in focal heavy hemosiderosis. It is of great interest that identical patterns of aluminum and iron deposition in hemodialysis patients were found in these three cases, This is the first report on histochemical demonstration of aluminum and iron deposition in diffuse pulmonary ossification, and detailed analysis of additional cases is needed.