Parathyroid hormone increases the expression level of matrix metalloproteinase-13 in vivo

Parathyroid hormone (PTH) increases serum calcium (Ca) by enhancing bone resorption and renal Ca reabsorption. However, detailed mechanisms of enhanced bone resorption by PTH remain to be elucidated. Although PTH has been shown to increase the expression level of osteoblastic matrix metalloproteinase (MMP)-13 in vitro, only limited results are available regarding the in vivo regulation of MMP expression. In the present study, we have examined expression levels of MMPs in PTH-infused rats. Infusion of 1.5 or 2.0 nmol/kg/day rat PTH(1-34) for 3 days resulted in a dose-dependent increase in serum Ca. PTH infusion also decreased serum phosphate levels and increased urinary excretion of Ca and phosphate. Infusion of PTH for 7 days resulted in less severe hypercalcemia and hypophosphatemia. Urinary Ca and phosphate excretion in rats infused for 7 days was less than that in rats infused for 3 days. Northern blot analysis showed that PTH infusion increased the expression level of MMP-13 in calvaria, although it did not affect MMP-2 expression. Furthermore, the time-course and severity of hypercalcemia and hypercalciuria correlated with the expression level of MMP-13. In situ hybridization also showed that PTH infusion increased the expression level of MMP-13 in femora. These results indicate that PTH enhances MMP-13 expression in vivo and suggest that PTH stimulates bone resorption at least partly by enhancing MMP-13 expression.

In vivo bone-forming capacity of human bone marrow-derived stromal cells is stimulated by recombinant human bone morphogenetic protein-2

In the present study, we investigated whether the in vivo bone-forming capacity of human bone marrow-derived stromal cells (HMSCs) could be enhanced by recombinant human bone morphogenetic protein-2 (rhBMP-2). The HMSCs obtained from seven donors (5-54 years of age) were passaged three to six times. Passaged HMSCs exhibited the osteoblastic phenotype in vitro, including: (a) an increase in alkaline phosphatase (ALP) activity in response to dexamethasone, ascorbic acid, and beta-glycerophosphate: and (b) mRNA expression for markers of osteoblastic lineage (ALP, osteopontin, osteocalcin, and parathyroid hormone-receptor) and BMP-2, -4, and -6 detected by reverse transcription-polymerase chain reaction. For the in vivo assay, transplants were subcutaneously implanted into nude mice as follows: group A (vehicle); group B (rhBMP-2); group C (HMSCs with vehicle); and group D (HMSCs with rhBMP-2). Transplants were obtained 2 and 4 weeks after implantation. Correlated radiographic findings, histological observations, and in situ hybridization using species-specific probes showed that the group B transplants contained bone tissue of mouse origin, which was observed at the periphery of the transplants. Four weeks after implantation, small amounts of HMSCs-derived bone tissue were detected at the periphery in two of seven transplants in group C. In contrast, five of seven group D transplants exhibited HMSCs-derived bone tissue, which was located at the center of the transplants and was surrounded by mouse bone tissue. Furthermore, HMSCs-derived chondrogenesis was detected in two of seven group D transplants. The results of the present study demonstrate that culture-expanded HMSCs preserve the osteoblastic phenotype, and the in vivo bone-forming capacity can be promoted by rhBMP-2.

A combinatorial code for gene expression generated by transcription factor Bach2 and MAZR (MAZ-related factor) through the BTB/POZ domain

Bach2 is a B-cell- and neuron-specific transcription repressor that forms heterodimers with the Maf-related oncoproteins. We show here that Bach2 activates transcription by interacting with its novel partner MAZR. MAZR was isolated by the yeast two-hybrid screen using the BTB/POZ domain of Bach2 as bait. Besides the BTB/POZ domain, MAZR possesses Zn finger motifs that are closely related to those of the Myc-associated Zn finger (MAZ) protein. MAZR mRNA was coexpressed with Bach2 in B cells among hematopoietic cells and in developing mouse limb buds, suggesting a cooperative role for MAZR and Bach2 in these cells. MAZR forms homo- and hetero-oligomers with Bach2 through the BTB domain, which oligomers bind to guanine-rich sequences. Unlike MAZ, MAZR functioned as a strong activator of the c-myc promoter in transfection assays with B cells. However, it does not possess a typical activation domain, suggesting a role for it as an unusual type of transactivator. The fgf4 gene, which regulates morphogenesis of limb buds, contains both guanine-rich sequences and a Bach2 binding site in its regulatory region. In transfection assays using fibroblast cells, the fgf4 gene was upregulated in the presence of both MAZR and Bach2 in a BTB/POZ domain-dependent manner. The results provide a new perspective on the function of BTB/POZ domain factors and indicate that BTB/POZ domain-mediated oligomers of transcription factors may serve as combinatorial codes for gene expression.

Identification of human GATA-2 gene distal IS exon and its expression in hematopoietic stem cell fractions

Transcription factor GATA-2 is essential for the proper function of hematopoietic stem cells and progenitors. Two first exons/promoters have been found in the mouse GATA-2 gene, and a distal IS promoter shows activity specific to hematopoietic progenitors and neural tissues. To ascertain whether the two-promoter system is also utilized in the human GATA-2 gene, we isolated and analyzed a P1 phage clone containing this gene. The nucleotide sequence of the human GATA-2 gene 5' flanking region was determined over 10 kbp, and a human IS exon was identified in the locus through sequence comparison analysis with that of the mouse GATA-2 IS exon. RNA blotting and reverse-transcribed PCR analyses identified a transcript that starts from the IS exon in human leukemia-derived cell lines. The IS-originated transcript was also identified in CD34-positive bone marrow and cord blood mononuclear cells, which are recognized as clinically important hematopoietic stem cell-enriched fractions. Phylogenic comparison of the human and mouse GATA-2 gene sequences revealed several regions in the locus that exhibit high sequence similarity. These results demonstrate that the GATA-2 gene regulatory machinery is conserved among vertebrates. The fact that the human IS promoter is active in the hematopoietic stem cell/progenitor fraction may be an important clue for the design of a vector system that can specifically express various genes in hematopoietic stem cells and progenitors.

Spatiotemporal change of rat collagenase (MMP-13) mRNA expression in the development of the rat femoral neck

The interepiphyseal region between the greater trochanter and the capital femoral epiphysis and the medioproximal portion of the femoral neck exhibit extensive morphological changes during the first 4 weeks after birth in rats. Previous reports show that matrix metalloproteinase-13 (MMP-13, rat collagenase) mRNA is expressed in bone and cartilage during embryonal development and fracture healing. We examined MMP-13 mRNA expression and compared it with the distribution of osteopontin and osteocalcine mRNA in the femoral neck. Moreover, we examined histomorphometric analysis in the femoral neck where the morphology changes rapidly. Histomorphometric analysis of the 4-week-old rat femoral neck showed a high rate of bone formation and resorption in the region where shape changed rapidly. Osteopontin mRNA was expressed diffusely along the endosteum. In contrast, MMP-13 mRNA expression was restricted to the medial endosteal portion near the cartilage-bone interface of the femoral neck in 15- and 28-day-old rats and in the deepest endosteal interepiphyseal region of 15-day-old rats. MMP-13 mRNA-expressing osteoblastic cells were also expressing osteopontin but not osteocalcin mRNA. MMP-13 mRNA-expressing cells differ from tartrate-resistant acid phosphatase (TRAP)-positive cells, and MMP-13 mRNA-positive cells are located adjacent to TRAP-positive cells. The results of the site- and cell-specific expression of MMP-13, taken together with its enzymatic property, suggest that MMP-13 plays an important role in morphological changes in the rat femur, at least during the third and fourth week after birth, and that MMP-13 itself is involved in the interaction between osteoblastic and TRAP-positive cells.

Expression of metalloproteinase-13 (Collagenase-3) is induced during fracture healing in mice

In fracture healing, a large amount of cartilage is formed, then rapidly replaced by osseous tissue. This process requires the transition of extracellular matrix component from type II to type I collagen. We investigated the expression of matrix metalloproteinase-13 (MMP-13), which has a high potential to cleave type II as well as type I collagen, during fracture repair in mouse ribs. In situ hybridization demonstrated that MMP-13 mRNA was present throughout the healing process. It was detected in the cells of the periosteum at day 1. As fracture callus grew, strong MMP-13 mRNA signals were detected in cells of the cartilaginous callus. In the reparative and remodeling phases, both hypertrophic chondrocytes and immature osteoblastic cells in the fracture callus expressed MMP-13 mRNA strongly. These cells were located adjacent to tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts at the sites of cartilage/bone transition. In osteoclasts, MMP-13 expression was not detected. The level of MMP-13 mRNA peaked at day 14 postfracture by northern blotting. Immunohistochemical staining showed that MMP-13 was detected primarily in hypertrophic chondrocytes. These results indicate that MMP-13 is induced during fracture healing. The site- and cell-specific expression of MMP-13 and its enzymatic property suggest that MMP-13 initiates the degradation of cartilage matrix, resulting in resorption and remodeling of the callus. In conclusion, MMP-13 plays an important role in the healing process of fractured bone in mice.

The mouse GATA-2 gene is expressed in the para-aortic splanchnopleura and aorta-gonads and mesonephros region

We previously reported that the mouse GATA-2 gene is regulated by two alternative promoters (Minegishi et al, J Biol Chem, 273:3625, 1998). Although the more proximal IG (general) promoter is active in almost all GATA-2-expressing cells, the distal IS (specific) promoter activity was selectively detected in hematopoietic tissues but not in other mesodermal tissues. We report here in vivo analysis of the GATA-2 locus and its regulatory characteristics in hematopoietic tissues of transgenic mice. Transgenes containing 6 or 7 kbp of sequence flanking the 5' end of the IS first exon direct expression of beta-galactosidase or green fluorescent protein (GFP) reporter genes specifically to the para-aortic splanchnopleura, aorta-gonads, and mesonephros (AGM) region, and in the neural tissues. In situ hybridization analysis showed that reporter gene expression specifically recapitulates the endogenous expression profile of GATA-2 in these tissues. The flk-1, CD34, c-kit, and CD45 antigens were identified in the GFP-positive cells from the AGM region and fetal liver, indicating that GATA-2 is expressed in immature hematopoietic cells. Deletion of 3.5 kbp from the 5' end of the 6.0 kbp IS promoter construct, including one of the DNase I hypersensitive sites, completely abolished hematopoietic expression. These experiments describe an early developmental GATA-2 hematopoietic enhancer located between 6.0 and 2.5 kbp 5' to the IS exon.

Maturational disturbance of chondrocytes in Cbfa1-deficient mice

Cbfa1, a transcription factor that belongs to the runt-domain gene family, plays an essential role in osteogenesis. Cbfa1-deficient mice completely lacked both intramembranous and endochondral ossification, owing to the maturational arrest of osteoblasts, indicating that Cbfa1 has a fundamental role in osteoblast differentiation. However, Cbfa1 was also expressed in chondrocytes, and its expression was increased according to the maturation of chondrocytes. Terminal hypertrophic chondrocytes expressed Cbfa1 extensively. The significant expression of Cbfa1 in hypertrophic chondrocytes was first detected at embryonic day 13.5 (E13.5), and its expression in hypertrophic chondrocytes was most prominent at E14.5-16.5. In Cbfa1-deficient mice, whose entire skeleton was composed of cartilage, the chondrocyte differentiation was disturbed. Calcification of cartilage occurred in the restricted parts of skeletons, including tibia, fibula, radius, and ulna. Type X collagen, BMP6, and Indian hedgehog were expressed in their hypertrophic chondrocytes. However, osteopontin, bone sialoprotein, and collagenase 3 were not expressed at all, indicating that they are directly regulated by Cbfa1 in the terminal hypertrophic chondrocytes. Chondrocyte differentiation was severely disturbed in the rest of the skeleton. The expression of PTH/PTHrP receptor, Indian hedgehog, type X collagen, and BMP6 was not detected in humerus and femur, indicating that chondrocyte differentiation was blocked before prehypertrophic chondrocytes. These findings demonstrate that Cbfa1 is an important factor for chondrocyte differentiation.

Origin of histiocyte-like cells and multinucleated giant cells in malignant fibrous histiocytoma: neoplastic or reactive?

The origin of histiocyte-like cells in malignant fibrous histiocytoma (MFH) remains controversial. To determine whether histiocyte-like cells and multinucleated giant cells show reactive or neoplastic proliferation, we transplanted human storiform-pleomorphic MFH to nude mice and investigated the origin of histiocyte-like cells using the DNA in situ hybridization (ISH) system. In addition, we analyzed the mRNA expression of mouse c-fms and human colony stimulating factor-1 (CSF-1); immunohistochemical expression of markers detectable in cells of monocyte/macrophage lineage. The DNA ISH revealed neoplastic proliferation of fibroblastic cells and bizarre multinucleated giant cells of human origin. Monocyte/macrophage lineage cells were seen in parental tumors, whereas they did not participate in neoplastic proliferation in transplanted tumors. The parental tumors expressed human CSF-1 mRNA and the histiocyte-like cells in transplanted tumors expressed 'mouse' c-fms mRNA. These results suggest that MFH induce infiltration of monocyte/macrophage and CSF-1 is one of the mediators involved in this phenomenon, because the human CSF-1 can act as a ligand to the mouse c-fms. Histiocyte-like cells in MFH should be considered as a reactive monocyte/macrophage lineage rather than as an element of neoplasm.

Number of osteoprogenitor cells in human bone marrow markedly decreases after skeletal maturation

Pluripotent mesenchymal stem cells in bone marrow differentiate to osteoblast progenitor cells. When the bone marrow cells are cultured in vitro, they form colony-forming units-fibroblastic (CFU-Fs) with exhibiting osteoblastic features such as expression of alkaline phosphatase (ALP) and formation of calcified nodules ex vivo. This article describes the effect of growth, maturation, and aging of the skeleton on human CFU-Fs harvested from human iliac bone marrow. Human bone marrow cells were harvested from the ilia of 49 women, and were cultured ex vivo for examination. The 49 subjects ranged in age from 4 to 88 years and were without metabolic bone disease. These aspirated bone marrow cells from human ilium exhibited osteoblastic phenotype such as alkaline phosphatase (ALP) activity, expression of osteocalcin (OSC) and parathyroid hormone-receptor (PTH-R) mRNA, and the formation of calcified nodules in vitro. The number of ALP-positive CFU-Fs and the ALP activity were quantified. The highest levels of ALP-positive CFU-Fs were observed in the young group, particularly in those under 10 years of age. The levels of ALP-positive CFU-Fs declined sharply after 10 years of age; those above 20 years of age exhibited a lower number of ALP-positive CFU-Fs, with a gradual decline with increasing age. These results indicate that change in the number of ALP-positive CFU-Fs may be associated with skeletal growth and maturation. The results also show that osteoblastic features such as ALP activity and capability of formation of calcification nodules were maintained even in the older subjects. These findings suggest that decreased activity of bone formation in the aged subjects could be, in part, caused by the decreased number of osteoprogenitor cells differentiating into osteoblasts because the number of ALP-positive CFU-Fs was one of the indices exhibiting bone-forming activity in the human marrow stromal cells.

Origin of bone-forming cells in human osteosarcomas transplanted into nude mice--which cells produce bone, human or mouse?

Osteosarcomas are malignant tumours producing osteoid and/or bone. It is difficult to distinguish tumour bone formation from reactive, based on their morphological features alone. The objective of this study was two-fold: to clarify the origins of bone-forming cells in human osteosarcoma transplanted into nude mice; and to examine the role of bone morphogenetic proteins (BMPs) in the tumour-induced osteogenesis. DNA in situ hybridization was carried out with digoxigenin (DIG) polymerase chain reaction (PCR) labelled DNA probes for human-specific 'Alu' and mouse-specific 'mouse L1 (m-L1)' genes. Human osteosarcoma cells, established cell lines of NOS-1, NOS-2, and HuO9, were transplanted separately into nude mice. Bone-forming cells of the bone in the NOS-1 or NOS-2 tumours were positive for Alu, while they were negative for m-L1. The cells lining the surface of trabeculae in the HuO9 tumour were positive for Alu, but a few of them were also positive for m-L1. The m-L1-positive cells expressed mouse osteocalcin and type 1 collagen mRNAs. These facts suggest that the mouse cells were involved in osteoid synthesis of the HuO9 tumour. The NOS-1 or NOS-2 tumours expressed human BMP 2-7 mRNAs, whereas the HuO9 tumour expressed human BMPs 2, 4, 5, and 7. The osteogenetic potential of the tumours may depend on the expression patterns of BMPs. These results demonstrate two distinct types of bone formation, by tumour cells and by an admixture of tumour and non-tumour cells. The present study showed that the HuO9 tumour produces chimeric bone formation. This is the first report to demonstrate the relationships between tumour cells and non-tumour cells in bone formation, using genetic markers.

Bindings of metallothionein to supranucleosomal fibers in mouse pancreatic nuclei after induction by 4-aminopyrazolo [3,4-D] pyrimidine

To examine intranuclear localization of metallothionein (MT) induced by administration of 4-aminopyrazolo [3,4-d] pyrimidine (4-APP), the present study of MT was performed by immuno-electron microscopy. One day after oral administration of 4-APP, the mouse pancreas removed and frozen with dry ice was cut at about 1 mm thickness. Pancreatic slices were reacted with anti-MT antibody, fixed with formaldehyde and glutaraldehyde, and embedded in hydrophilic Lowicryl K4M resin. Ultrathin sections were reacted with the secondary antibody labelled with colloidal gold, and stained both with uranyl acetate and with lead citrate. It was found that the MT site was shown simultaneously in the chromatin and in the rough endoplasmic reticulum of mouse pancreatic exocrine cells one day after administration of 4-APP. The structure of MT-binding chromatin was composed of supranucleosomal fibers, but not of nucleosomal fibers.

[Immunohistochemical study of PCNA, EGFR, c-erbB-2 and p53 in carcinomas of large intestine]

Immunohistochemical stainings for EGFR, c-erbB-2, p53 and PCNA were performed on 36 and 30 cases of intramucosal and advanced carcinomas of large intestine. Positive rate was 58.3%, 41.6%, 58.3% and 60.6% for EGFR, c-erbB-2, p53 and PCNA in the intramucosal cases, and 66.7%, 50%, 66.7% and 72.6% in the advanced ones, respectively. Relationship between EGFR and c-drbB-2 was more significant in the advanced carcinomas than that in the intramucosal ones. It seemed likely that relationship between p53 and c-erbB-2 was more significant than that between p53 and EGFR. Positive rate of PCNA was of intimate relationship among that of EGFR, c-erbB-2 and p53, and the positive rate increased in the advanced carcinomas.

[Study on mucosal carcinomas of the large intestine, polypectomized for the recent 5 years]

Intramucosal carcinomas of the large intestine, polypectomized from 1988 to 1992 were investigated. Out of 111 lesions of intramucosal carcinoma, 106 cases (95.5%) co-existed with adenoma. The incidence of co-existence with adenoma was 0%, 14.4%, 31.5%, 26.1%, 18.9% and 9.0% in the lesions within 4mm, 5-9mm, 10-14mm, 15-19mm, 20-29mm, and over 30mm in diameter, respectively. The incidence of gross findings in the co-existed cases of cancer and adenoma was 0.9%, 15.1%, 32.1%, and 51.9% for IIa, Is, Isp, and Ip types, respectively. Histological incidence of co-existed adenomas was 63.2%, 31.1% and 5.7% for tubular, tubulovillous and villous types. Occupation rate of cancer tissue was within half in the majority of co-existed lesions.

[Immunohistochemical study of growth factors and oncogenes in gastric carcinomas]

Immunohistochemical staining for EGF, EGFR, c-erbB-2, p53, K-ras and PCNA was performed on the formalin-fixed, paraffin embedded sections of resected gastric carcinomas. A relatively high positive rate was observed for EGFR and c-erbB-2 in the well-differentiated adenocarcinomas and p53 in the poorly-differentiated adenocarcinomas. The positive rate of these factor was higher in the advanced cases than in the early cases, and also in the deep invasive area than the superficial area. According to the PCNA staining, a relatively high positive rate was observed in the well-differentiated adenocarcinomas compared with the early cases of poorly-differentiated adenocarcinomas, but the positive rate was markedly higher in the advanced cases of the latter. Typical signet-ring cell carcinomas showed the lowest positivity rate compared with the other histological types of gastric carcinomas.

[Immunohistochemical study for growth factor and oncogene on atypical epithelium of the stomach]

Almost all atypical epithelial lesions of the stomach consist of atypical cells in the superficial part of the glands and nonatypical cells in the deeper portion of the glands. A transition zone was formed between the superficial atypical gland cells and the deeper nonatypical gland cells. Positive cells were widely demonstrated with immunohistochemical stains for PCNA in the superficial atypical glands and transition zone. The rate of PCNA positivity was 37.7%. However, a small number of positive cells for EGFR (8.5%), c-erbB-2(11.3%), p53(11.3%) and c-K-ras(1.7%) were found in ATP. The incidence of positivity for these factors was low compared with that for carcinomas. The percentages of positive cells for EGFR(1.5%) and c-erbB-2(4.5%) were very low in intestinal metaplasia.

[Immunohistochemical study of the lymph-follicles and lymphocytes in the gastric mucosa]

Immunohistochemical stainings according to ABC method (UCHL-1,L-26,MT-1,MB-1,IgG,IgA,IgD,IgM, kappa, lambda, LN-1 and LN-2) for the lymphocytes in the germinal center, mantle zone and infiltrative lymphocytes in the gastric mucosa of 30 cases of chronic gastritis and 10 cases of reactive lymphoreticular hyperplasia (RLH) were performed. Lymphocytes in the germinal center and mantle zone consisted usually of B-cells positively stained by L-26 and MB-1. However, in the interstitially infiltrative cells,T-cells positively stained by UCHL-1 and MT-1 were not infrequently contained. Immunoglobulin stainings revealed marked positivity for IgG,IgA,IgD,IgM, kappa and lambda in the interstitial lymphocytes and plasma cells. As to the RLH, small number of T-cells scattered in the germinal center and surrounding area of lymph follicles, and large number of T-cells were found among the follicles, where B-cells were more infrequently found than in the interstitial area of propria mucosae. Confusion of enlarged germinal centers and monotonous proliferation of lymphocytes among the lymph follicles showing monotonous positivity for the stains of heavy and light chains in the cases of RLH were suggestive of malignant change.

[Immunohistochemical study of EGF and EGF-R on the esophageal carcinomas--from a standpoint of depth of invasion]

We performed immunohistochemical stainings for epidermal growth factor (EGF) and epidermal growth factor receptor (EGF-R) on 63 resected esophageal carcinomas without preoperative treatment and 12 cases with preoperative radiation to clarify a relationship between positivity and depth of invasion. EGF and EGF-R showed a similar positivity (75% of early cases and 88.9% of advanced ones invaded beyond submucosa). In advanced carcinomas, the positivity in each layer was 75% in the mucosa, 86.7% in the submucosa and muscle layer, and 93.3% in the adventitia. All lesions of nodal metastases were positive for these stainings. Sixty % of cases with preoperative radiation were positive. The degenerated cells showed weak positivity. However, the viable cells showed similar positivity to those of non-treated cases.

Heterotopic pancreas of the stomach. Histogenesis and immunohistochemistry

Ordinary histological investigation has suggested that heterotopic pancreas of the stomach may have two types of histogenesis; one is development from immigrated fetal pancreas tissue, and the other is development from primitive gastric mucosal epithelium following penetration into the submucosa with subsequent erroneous differentiation into pancreas tissue. It is suspected that type-I lesions include the majority of cases caused by immigration from fetal pancreas, and that some type-II cases arise through erroneous differentiation of primitive gastric mucosal epithelium. With regard to immunohistochemical findings, cells positive for pancreatic polypeptide and amylase were much more numerous in the acini of type-I cases compared with type-II cases. Positive cells were found not infrequently in the acini of type-II cases after staining for pancreatic polypeptide, insulin, glucagon, somatostatin, serotonin, and gastrin. On the other hand, a small number of cells in islets were not infrequently positive for alpha 1-antitrypsin, alpha 1-antichymotrypsin, and amylase. It is considered that in the heterotopic pancreas, ductal cells have the potential to differentiate into acinar cells and islet cells, as is the cases in the orthotopic pancreas.

[Histological study of heterotopic pancreas tissue of the stomach--histogenesis and immunohistochemical findings]

Forty resected cases of heterotopic pancreas (15 of Heinrich's type I and 25 of type II) in the stomach were investigated. Acinic cells were more remarkably positive by pancreatic polypeptide and amylase in the cases of type I consisting of acinic cells, ducts and islet cells compared with those in type II consisting of acinic cells and ducts. Staining behavior by insulin, gastrin, glucagon, somatostatin and serotonin was similar to that of normal pancreas. However, the intestinal epithelium containing goblet cells and pyloric gland-like glands consisting of the cells with clear cytoplasm were not infrequently produced from the ducts in the lesions of type II. Muscle fibers with transition to muscularis mucosae were more frequently intermingled in the lesions of type II compared with type I. Acinic cell-differentiation in the mucosa apart from the main lesion was found in several cases of type II. It was suspected that there are two types of histogenesis for the heterotopic pancreas in the stomach; one arises from the fetal immigration of pancreas tissue in the stomach and the other from the immature gastric mucosal penetration into the submucosa with secondary differentiation to the pancreas tissue.

[Histopathological study of resected esophageal cancers between with and without preoperative radiation therapy]

A histopathological study was performed on 53 radiated and 123 non-radiated resected esophageal cancers. The preoperatively radiated (3,000 to 4,000 rads) lesions were usually smaller than the non-treated ones due to the reduction in tumor tissue, and the incidence of infiltrative ulcerated type lesions (Borrmann 3-like) was markedly higher in the former. Histologically, the incidence of moderately-differentiated squamous cell carcinoma (SCC) was lower and that of well-differentiated SCC was higher in the radiated cases, probably due to the high sensitivity of the former type compared with the latter. The incidence of vascular involvement was lower in the radiated cases than the non-treated cases because of the reduction in vessel size due to fibrosis and scar caused by the radiation. However, lymph-nodal metastasis was more frequent in the radiated cases in which the more deeply invaded lesions were included compared with the non-treated cases.

[Clinicopathological study of 65 cases of aberrant pancreas in the stomach]

Sixty-five cases of aberrant pancreas in the gastric wall in 9,650 resected stomach were investigated clinicopathologically. Average age was 44.5 and male to female ratio was 3.5 to 1. Eighty-eight per-cent of the lesions were found in the pylorus and antrum, and the lesions were frequently found in the posterior wall, anterior wall and greater curvature. The size of the lesions varied from 0.7 cm to 4.5 cm in diameter and 89.1% of them were within 3 cm in diameter. The protruded lesions were usually found in the space between submucosa and propria muscularis, and the flat-elevated ones were frequently found in the space between propria muscularis and subserosa. The histological incidence of Heinrich type I, II and III were 38.8%, 52.2% and 9.0%, respectively. There was no case of malignant change in the present series.

[The relation of stone and carcinoma of the gallbladder based on the mucosal findings]

Based on the mucosal findings in gallbladder patients, intestinal metaplasia was found in 18.4% of such cases without a stone or a carcinoma, in 30% of the with a bilirubin stone, in 37.7% of those with a cholesterin stone, in 69.1% of those with a carcinoma but without a stone and in 78.9% of those with both a carcinoma and a stone. In contrast the incidence of a well differentiated adenocarcinoma was more frequent in the cases with a stone (more often a cholesterin stone than a bilirubin stone) than in cases without a stone. Similarly, the incidence of intestinal metaplasia was more frequent in those with a cholesterin stone than in those with a bilirubin stone. Further, small size lesions were found to be more frequent in the cases of a cancer with a stone. Granular early carcinomas within the superficial muscle layer are usually resected under the diagnosis of gallstone, whereas early carcinoma that protrude are resected as a carcinoma.

[A resected case of mucin-secreting malignant papillomatosis (villous tumor) of ductus choledocus and left intrahepatic duct]

A resected case of remarkably mucin-secreting malignant papillomatosis (villous tumor) of the ductus choledocus and left intrahepatic duct in a 79 year-old female was reported. In this case, cholecystectomy and choledocho-duodenal anastomosis for the gallbladder stone were performed 14 years ago. Villous or papillary tumors arose in the ductus choledocus and spread into the left intrahepatic duct. Histological examination revealed villous proliferation similar to the villous tumor in the large intestine, in which cancerous and adenomatous changes intermingled showing remarkable mucin secretion. Tumor invasion was limited in the wall without extracanal dissemination, and nodal metastasis was absent. Interestingly, exceeding mucin-secretion was observed as the frog-egg like appearance in the ductus choledocus and as the regurgitation into the stomach by the endoscopic examination. This type carcinomas usually show favorable prognosis compared with the ordinary adenocarcinomas of the bile duct.

[A clinicopathological study of signet-ring cell carcinomas of the stomach]

Surgically resected signet-ring cell carcinomas of the stomach have been clinicopathologically investigated. Although this type of carcinoma was found to be widely spread in the propria mucosa, a deeper invasion beyond the submucosa appeared more slowly than in other types of carcinomas. For example, the larger the early carcinoma in which the invasion was restricted to within the submucosa, the greater the incidence of a signet-ring cell carcinoma increase, especially in cases involving the mucosa. The incidence of a nodal metastasis was found to be lower than in cases of a moderately and poorly-differentiated adenocarcinoma in the early stage. However, when the signet-ring cell carcinomas invaded beyond the submucosa, the tumor cells spread rapidly and widely in the wall with a subsequent abdominal implantation, causing ascites and peritonitis carcinomatosa. It seemed likely that this deep invasion was accelerated by cellular change, such as the enlargement of nucleus, cellular atypy, and a decreased mucin production. As signet-ring cell carcinoma arise from the neck of glands and infiltrate the propria mucosae under the superficial epithelium, diagnosis by the barium enema and an endoscopic examination is very difficult in the case of small-size lesions. In lesions greater than 1 cm in diameter, these carcinomas usually showed an erosive and/or ulcerated appearance.

[Intestinal metaplasia of the stomach--the significance of single-layer and double-layer metaplasia]

Resected early gastric carcinomas (1,690 cases) and atypical epithelial proliferations (adenomatous lesions, 310 cases) were investigated by the 5 mm-wide step sections. There were two types of intestinal metaplasia; double-layer type, where intestinal metaplasia was in the superficial area with the remaining pyloric or pseudopyloric glands in the deep region of the propria mucosae, and single-layer type, where intestinal metaplasia was usually present in a single layer without remaining deep non-metaplastic glands. These two types of intestinal metaplasia were usually found in the same specimen, however, most of the atypical epithelial proliferations (adenomatous lesions) arose from the area of intestinal metaplasia showing a double-layer type. The mitotic activity was usually found in the transitional zone showing these double-layer intestinal metaplasia. Atypical epithelial cells arose in the transitional zone of the double-layer intestinal metaplasia and spread into the luminal side by budding or replacement of existing epithelial cells. However, the author suspected that the cells in the under area of the transitional zone reproduce non-atypical cells to supplement the cells in the existing pyloric or pseudopyloric glands. On the other hand, atypical epithelial proliferations of single-layer type were rarely found showing a concaved appearance. Some of them may arise from the intestinal metaplasia of single-layer type, where the mitotic region moved towards the lower 1/3 of the glands. It seemed likely that most of the well-differentiated adenocarcinomas arise with intimate relation to these two types of intestinal metaplasia, where the incidence of malignant change of each type has been unknown.

[Study of early gastric carcinoma from the standpoint of size]

1,112 cases of resected early gastric carcinoma without invasion beneath the propria muscularis were investigated for the location, gross findings and histological findings mainly from a standpoint of size. The incidence of intramucosal carcinomas was 92.7% in the size within 1 cm in diameter, 68.9% in 1 to 2.9 cm, 48.8% in 3 to 4.9 cm and 37.6% beyond 5 cm. Although the incidence of poorly-differentiated adenocarcinomas was 37.9% in the cases within 5 cm, the incidence in the cases beyond 5 cm was 50.8% (most of them consisted of signet-ring cell carcinoma). The larger the tumor size, the more the intestinal metaplastic type carcinomas decreased and the signet-ring cell carcinomas increased. It was suggested that the signet-ring cell carcinoma infiltrates in the propria mucosae for a long time compared with the other type carcinomas.

Mucosal dysplasia of gallbladder: isolated and adjacent lesions to carcinoma

Isolated dysplasia was found in 46 (54 lesions) of 2,027 gallbladders, which were histologically studied by serial step sectioning. Average age of patients was 63.8 with a male-to-female ratio of 1 to 3. These lesions, excluding polypoid lesions of adenoma, were located most frequently in the fundus and body, showing flat granular or irregular appearance. As to the size, 68.6% were smaller than 1 cm in diameter (89% were smaller than 2 cm). Most mild dysplasias were found in small lesions less than 0.5 cm in diameter and moderate ones in lesions of less than 1.5 cm, though severe dysplasias were found in various sizes. Gallstones were found in 86.9% of the cases with dysplasia, and intestinal metaplasia and pseudopyloric gland metaplasis were found in 80.4% and 100%. Dysplasia adjacent to carcinoma was found in 46 of 110 cases (41.8%), and this change was frequently found in lesions at the early stage and well-differentiated carcinoma. It seems that mucosal damage caused by a stone and subsequent inflammation may be important in the histogenesis of intestinal metaplasia and dysplasia.

[Dysplasia of the gallbladder]

Out of 2,027 resected gallbladders that were examined, 46 (2.2%) manifested dysplasia and, to study this further, step sections, 5 mm apart, were performed. The average age of these dysplastic cases was 63.8 years, with a male to female ratio of 1:3. The most frequent dysplastic sites in the gallbladder were in the fundus and the body. Excluding adenomas, polypoid lesions, the dysplasia appeared flat, granular, or irregular. As to diameter, 68.6% were within 1 cm, and 89% were no more than 2 cm. The majority of cases manifesting mild dysplasia had lesions of up to 5 mm in size while the lesions seen in moderate cases were within 2 cm. Stones were found in 80.4% of the cases, and incidences of intestinal metaplasia and pseudopyloric gland metaplasia were found in 80.4% and 100% of these cases, respectively. Incidences of dysplasia adjacent to the carcinoma was seen in 41.8% of the cases, and frequently found in early-stage lesions and well-differentiated carcinomas. Our findings have led us to believe that recognition of the intestinal metaplasia-dysplasia-carcinoma sequence is important.

[Hypothesis for the histogenesis of atypical epithelial proliferation in the stomach]

Atypical epithelial proliferation has been described in various ways, such as ATP, and IIa-subtype, an adenoma, and as dysplasia in the stomach. Although the gross findings are variable, showing a protruded and/or concave appearance, these lesions have an intimate relationship with the intestinal metaplasia. Atypical epithelial proliferation lesions develop in 2 fashions. The first type, of proliferation is a superficial type with the capability of transition to the deep non-atypical glands, and may arise in association with a superficial type of intestinal metaplasia. The second type of proliferation may arise from an area affected by complete intestinal metaplasia, in the mitotic region in the bottom of the gland. The majority of the protruded types may arise from the first lesion described, and the majority of the concave types from the second.

Protruded variants in solitary ulcer syndrome of the rectum

A review of 21 patients with protruded lesions in solitary ulcer syndrome of the rectum confirmed by resection is presented. Symptoms were usually the passage of blood and mucus per rectum, alteration of bowel habit, anorectal pain and rectal prolapse. Solitary or multiple polypoid lesions were found within 15 cm of the anal margin and were usually sited anteriorly. Fifteen of the patients were men and 8 were women with a mean age of 37.1 years. The diagnosis was made on the basis of histopathology; 1) fibrous obliteration of muscle fibers, 2) reactive hyperplasia of the mucous membrane with villous configuration or mild pseudoinvasion. These changes have been observed in complete rectal prolapse, colonic intussusception, and localized colitis cystica profunda, suggesting a common pathogenesis. The histological findings were almost the same as in the ulcerative lesions of this syndrome except for remarkable regenerative hyperplastic changes such as a relatively high incidence of mucous cell proliferation, dilatation of glands and serrate change in the cases showing protrusion. In the pathogenesis, the occult mucosal prolapse in association with excessive straining may be of particular importance, so that the lesions might be termed mucosal prolapse syndrome of the rectum.

[Squamous metaplasia of the gastric mucosa associated with an aberrant pancreas]

A squamous metaplasia was found in the superficial regenerative epithelium on the aberrant pancreas tissue (Heinrich type II), situated in the posterior wall of the antrum. The squamous epithelium was positively stained by keratin, according to the PAP method, and intestinal metaplasia also was found surrounding the squamous metaplasia. In this case, it was decided that the squamous metaplasia development was associated with the regenerative change of the superficial ulceration. Squamous metaplasia is extremely rare in the stomach, and thus it was difficult to consider that the adenosquamous cell carcinoma of the stomach had developed from the antecedent squamous metaplasia.

Dysplasia of gallbladder. Its pathological significance

Twenty-three cases of dysplasia of the gallbladder and 38 cases of carcinoma with surrounding dysplasia were investigated. The dysplasia did not show any remarkable lesion and consisted of atypical basophilic cells with oval or round nuclei. The ratio of nucleus to cytoplasm (N/C) ratio was usually larger than the normal epithelial cells. For the combined dysplasia, it has been considered that 1) the dysplasia arose as well-differentiated carcinoma, 2) appeared synchronously, 3) arose secondarily, and 4) appeared as a precancerous lesion. Intestinal metaplasia, dysplasia, and carcinoma showed similar characteristics as to location and mucin-chemistry. According to CEA stain by PAP method, the dysplasia and carcinoma showed similar characteristics. It may be considered that the sequence of intestinal metaplasia-dysplasia-carcinoma is important.