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Biomedical subjects

T Sakakura

Publications and source records attributed to T Sakakura.

At least 37 records · Page 2Linked to original sources
PubMed1999

Reconstruction of pleomorphic adenoma of the salivary glands in three-dimensional collagen gel matrix culture.

The morphogenesis of salivary gland pleomorphic adenoma was examined in vitro using three-dimensional (3-D) collagen gel culture. Pleomorphic adenoma cells were isolated from three parotid gland tumours and cultured as monolayers, after which they were subcultured in floating-collagen gel sandwiches. Cells cultured in both conditions were immunohistochemically characterized and compared using antibodies against various proteins representative of each histological component of salivary glands. Monolayers had myoepithelial characteristics, being positive for vimentin and alpha-smooth muscle actin. In collagen gels, however, the cells assembled in epithelial nests, showing an architecture similar to that of pleomorphic adenoma. The nests were composed of duct-lining epithelial cells that were positive for epithelial markers, surrounded by myoepithelial cells. Collagen gel culture induces multidirectional differentiation of adenoma cells, suggesting that pleomorphic adenomas originate from stem or reserve cells.

Actins↗
PubMed1999

Involvement of tenascin-C in proliferation and migration of laryngeal carcinoma cells.

Tenascin-C (TN-C) is an extracellular matrix glycoprotein upregulated in various pathological processes. In this study, we investigated its distribution in dysplasia and carcinoma of the human larynx using immunohistochemistry and in situ hybridization (ISH) techniques. In all cancer tissues, TN-C immunostaining was markedly increased in the stroma, especially around the cancer cell nests. In addition, cytoplasmic staining of cancer cells was also observed in 62.5% of the invasive cases, the cells being distributed in the periphery of the nests adjacent to the stroma. TN-C mRNA signals in cancer cells were detected in all six cases examined by ISH. Furthermore, in vitro evaluation of the roles of TN-C demonstrated an increase in the proliferating cell fraction in a dose-dependent manner. In a wound closure assay, the addition of TN-C promoted migration. We conclude that TN-C secreted by cancer cells may be involved in their proliferation and migration in an autocrine fashion.

Carcinoma in Situ↗
PubMed1999

Low cytoplasmic pH causes fragmentation and dispersal of the Golgi apparatus in human hepatoma cells.

The centrosomal localization of the Golgi apparatus in interphase cells is thought to be maintained by retrograde microtubule-based motility. It is well established that, when intracellular pH is lowered, lysosomes and endosomes, also showing pericentrosomal localization, translocate towards the plus ends of microtubules within 15 min. In this study, we found that prolonged incubation in low pH medium (pH 6.6) with 20 mM Na acetate induced the fragmentation and dispersal of the Golgi apparatus in the human hepatoma cell line PLC/PRF/5. The fraction of Golgi-dispersed cells increased in a time-dependent manner, and reached over 60% after the 16-h incubation. The cytoplasmic pH was dropped to approximately 7.10. Replacement with normal pH medium restored the structure and localization of the apparatus within 30 min. In the low pH condition, the microtubular network and endoplasmic reticulum appeared normal, and cytoplasmic dynein was still bound to the fragmented Golgi membranes. These findings suggest that low cytoplasmic pH suppresses the retrograde movement of the Golgi apparatus as well as that of lysosomes and endosomes.

Carcinoma, Hepatocellular↗
PubMed1999

The expression of transforming growth factor beta (TGF-beta) in the synovial membrane of human temporomandibular joint with internal derangement: a comparison with tenascin expression.

We examined the expression of the transforming growth factor beta (TGF-beta) in 28 human temporomandibular joint (TMJ) samples (internal derangement of TMJ and control specimens) by an immunohistological method using paraffin-embedded tissues and a polyclonal antibody specific to human TGF-beta. The resulting reaction of TGF-beta expression divided into three types as follows. The first type, around the fibrocyte and in the lacunae of chondrocytes in the disc. The second type, at the stroma of the mildly hypertrophic synovial membrane and severely hypertrophic synovial membrane. The first type was observed in all the cases including the control cases. The second type showed only in the internal derangement of TMJ, and its expression pattern resembled that of tenascin (TN) within the stroma of hypertrophic synovial membranes. In conclusion, TGF-beta and TN were distributed in the affected synovial membrane of TMJ with internal derangement. These findings suggested that TGF-beta and TN might have a close relationship with synovitis, followed by tissue repair.

Adult↗
PubMed1999

Expression of fibronectin isoforms in human breast tissue: production of extra domain A+/extra domain B+ by cancer cells and extra domain A+ by stromal cells.

The expression of fibronectin (FN) isoforms including extra domain A (EDA) and extra domain B (EDB) segments, was investigated in 36 invasive ductal carcinomas and 13 benign tumors of human breast tissues by in situ hybridization using probes specific to alternative splicing sites. Signals for the constant region of FN mRNA in cancer cells were found in 53% of the invasive ductal carcinomas. The EDA+ and EDB+ mRNA signals were found in 47% and 33%, respectively. Stromal cells expressing FN, EDA+ and EDB+ mRNA signals were present in 100%, 69% and 14% of cases, respectively. Expression of FN mRNAs by cancer cells was most frequent in intraductal lesions or large cancer nests, and that by stromal cells was associated with desmoplastic areas. In representative cases, proportions of FN mRNA-positive cancer cells expressing EDA and EDB segments were 45% and 39%, respectively, signals for both being frequently found in the same cells. EDA+ and EDB+ mRNA were labeled in 25% and 6% of the FN mRNA-positive stromal cells, a large proportion thus being EDA-/EDB- FN. In conclusion, the splicing pattern of FN pre-mRNA is dependent on the cell type and histology of breast cancer tissues. The observed lack of expression in fibroadenomas and other benign conditions suggests a link with tumor progression.

Alternative Splicing↗
PubMed1999

The localization of matrix metalloproteinase-3 and tenascin in synovial membrane of the temporomandibular joint with internal derangement.

OBJECTIVES: The aim of this investigation was to study the immunohistochemical localization of MMP-3 and tenascin in the temporomandibular joint and to compare it with control specimens. MATERIALS AND METHODS: Localizations of matrix metalloproteinase-3 (MMP-3) and tenascin in the temporomandibular joint disc and the synovial membrane in 26 human temporomandibular joint samples (internal derangement of TMJ; n = 16, and control; n = 10) by an immunohistological method with monoclonal antibodies specific to human MMP-3 and tenascin. RESULTS: MMP-3 was not distributed in control specimens while it was observed in the internal derangement cases. MMP-3 showed two staining profiles: (1) diffuse staining was observed within the stroma of severely deformed disc with osteophyte and/or disc displacement (three of 16 specimens); and (2) the localization was specifically detected on the surface of severely hypertrophic synovial membrane (six of 16 specimens). The latter localization pattern resembled that of the tenascin on the surface of the severely hypertrophic synovial membrane. CONCLUSION: Comparative localization of MMP-3 and tenascin revealed intense staining for both in the synovial membrane presenting inflammation, proliferation and hypertrophy. These findings suggest that tissue repair and remodeling in the temporomandibular joint disc and the inflammatory hypertrophic reaction in the synovial membrane might proceed at the same time.

Adult↗
PubMed1998

Expression and degeneration of tenascin-C in human lung cancers.

Tenascin-C is an extracellular matrix glycoprotein produced in response to epithelial-mesenchymal interactions during organogenesis and tissue remodelling. It has therefore been proposed as a stromal marker for epithelial malignancy. To test this hypothesis, 30 human lung cancers, presenting a variety of clinicopathological features, and six specimens of normal tissue were examined by Western and Northern blotting of tenascin-C protein and mRNA. The results obtained were: (1) elevated tenascin-C expression was detected in all 30 cases by Western blotting, with mRNA increase in 22 of them; (2) mRNA for a large isoform of tenascin-C, including an alternatively spliced sequence, was expressed in lung cancer tissues but not in normal lungs; and (3) metastasis to lymph nodes was frequently found in cases whose tenascin-C was degraded into small fragments. These results suggest that tenascin-C degradation can be used as a marker for metastatic potential of a tumour.

Adenocarcinoma↗
PubMed1998

Morphogenic activity of fibroblast growth factor-2 on primary neural precursor cells in three-dimensional culture.

Mouse neural precursor cells (NPC) were dissociated from fetal heads at the 10th day of gestation. When clumps of NPC were cultured in collagen gel, they grew and reorganized neural tube-like structures in medium containing fetal calf serum at 10% and supplemented with insulin, transferrin, cholera toxin and selenite. However, dissociated NPC died when they were cultured in collagen gel at low density in the same medium. Addition of fibroblast growth factor-2 (FGF-2) to this culture stimulated growth of NPC and formation of neural tube-like structures. The requirement for FGF-2 disappeared in high seeding density culture: they grew and formed neural tube-like structures without FGF-2. The structures formed in collagen gel were immunohistochemically positive against anti-FGF-2 antibody. The results show that the three-dimensional culture system provides a useful tool to study the roles of FGF-2 in morphogenesis of the central nervous system.

Animals↗
PubMed1998

Overexpression of caltractin gene in tumor-infiltrating lymphocytes.

Differential display is a technique which relies on the polymerase chain reaction to identify messenger RNA differences between related tissue samples. We have employed an improved differential display technique, called fluorescent differential display (FDD), to identify the genes that are differentially expressed in normal and malignant mammary tissues. From FDD fingerprints, we identified changes in intensity of approximately 3% (185 bands) of a total of 5, 837 bands. Each of these 185 bands represented a differentially expressed gene, and we focused our attention on the expression of the gene for caltractin, a member of the calcium-binding EF-hand protein superfamily. Northern blot analysis revealed that the level of mRNA for caltractin was higher in breast carcinoma than in corresponding normal tissue in all cases tested (5/5). Moreover, high-level expression of the gene for caltractin was also recognized in other malignant tumors, such as hepatocellular carcinoma (HCC), gastric cancer and leiomyosarcoma. The results of in situ hybridization showed strong stainings for caltractin mRNA in tumor-infiltrating lymphocytes (TIL), but not in malignant tumor cells. Our data suggests that the caltractin gene might be associated with the function of TIL.

Adult↗
PubMed1998

[A case of successful hypospadias repair without infection using recombinant human granulocyte-colony stimulating factor (rhG-CSF) for idiopathic neutropenia].

A boy aged 1 year 8 months, who was referred to our hospital because of hypospadias, was followed for 17 months under a diagnosis of idiopathic neutropenia. He was given recombinant human granulocyte colony-stimulating factor (rhG-CSF) at a dosage of 37.5 micrograms/day for 2 days preoperatively. His absolute neutrophil count in peripheral blood increased to more than 500/microliter, and hypospadias repair (free graft method) was performed. RhG-CSF was administered on the first, sixth, and eleventh days after the operation, and the postoperative course was uneventful. During pediatric surgery in patients with neutropenia, appropriate administration of rhG-CSF may be useful for preventing infection.

Granulocyte Colony-Stimulating Factor↗
PubMed1998

[Composite pheochromocytoma with ganglioneuroma in the adrenal gland: a case report].

A 67-year-old male demonstrated a right adrenal tumor at another hospital, and consulted our hospital for surgical treatment. Abdominal computed tomography revealed a 13 x 12 cm mass in the right adrenal region. Serum and urinary adrenaline levels were high, and the catecholamine levels in the blood sample of the selective adrenal vein were also high. The tumor was 1,325 g in weight and 13 x 9 x 18 cm in diameter. Pathological diagnosis was a mixed neuroendocrine-neural tumor. It was composed of pheochromocytoma and ganglioneuroma. This combination in the adrenal gland is rare. We reviewed 3 previously reported cases of composite pheochromocytoma with gangloineuroma in the adrenal gland in the Japanese literature, and this is considered to be the fourth case.

3-Iodobenzylguanidine↗
PubMed1997

Expression of fibronectin and tenascin-C mRNA by myofibroblasts, vascular cells and epithelial cells in human colon adenomas and carcinomas.

To understand the mechanisms of tissue remodeling during cancer progression, it is important to know the type of cells that actively express extracellular matrix (ECM) proteins. Twenty-nine adenocarcinomas, 5 adenomas and non-neoplastic mucosa samples were therefore investigated to determine their fibronectin (FN) and tenascin-C (TN-C) expression using in situ hybridization (ISH) and immunohistochemical staining. In the non-neoplastic mucosa, no mRNA signals were found. Two of the adenomas demonstrated positive signals in peri-cryptal cells and the vessels. In the cancers, TN-C and FN mRNAs were found in 86% and 96% of the total cases, respectively. The signals were mainly detected in myofibroblasts, labeled with alpha-smooth muscle actin, in the cancer stroma. TN-C mRNA-positive cells were often observed in localized areas, such as in cancer stroma associated with invading edges and/or in host tissues surrounding the invading cancer front, but rarely in the center of the tumors. FN mRNA-positive cells were more widely spread throughout the cancer stroma, although they were also frequently observed at invading edges. Vascular cells in cancer tissues were also labeled. In 10 specimens, cancer cells themselves expressed FN and/or TN-C mRNA. Comparison with histo-pathological findings revealed positive relationships between the degree of mRNA expression of FN and TN-C and the depth of invasion as well as the frequency of metastasis to lymph nodes. The expression of FN and TN-C by myofibroblasts, vascular cells and cancer cells could be important for the remodeling process of neoplastic tissues during cancer development and progression.

Adenocarcinoma↗
PubMed1997

Co-expression of tenascin and fibronectin in epithelial and stromal cells of benign lesions and ductal carcinomas in the human breast.

Tenascin (TN)-C and fibronectin (FN), which are glycoproteins of the extracellular matrix (ECM), are up-regulated in cancer tissues, including breast cancer. For assessment of their involvement in cancer invasion, it is important to know which cells are responsible for their production and secretion. The distribution of cells expressing TN and FN mRNAs in benign and malignant human breast tissues was therefore analysed by in situ hybridization, using digoxigenin-labelled cRNA probes, in addition to demonstrating the proteins immunohistochemically. Both mRNAs were expressed in epithelial cancer as well as in stromal cells in a large fraction of the tumours, with co-expression in individual cells. In cancers with intraductal components and/or those consisting of large nests, the mRNAs were more often expressed in the cancer than in the stromal cells. In scirrhous carcinomas, in contrast, the stromal cells were almost always positive for TN and FN mRNAs, while the cancer cells only rarely exhibited TN or FN expression. In benign lesions including adenosis, fibroadenoma and intraductal papilloma, the expression patterns also varied. These findings indicate that TN and FN co-expressed by cancer cells and stromal cells are probably involved in the intraductal extension and early invasion of cancer cells and in the remodelling of cancer stroma.

Adenocarcinoma, Scirrhous↗
PubMed1997

The change in tenascin expression in mouse uterus during early pregnancy.

PURPOSE: Our aim was to examine the changes in spatiotemporal tenascin (TN) expression in mouse uterus during early pregnancy, when the uterine tissue undergoes a tremendous restructuring. METHODS: Using immunohistochemistry and in situ hybridization, the changes in distribution of TN protein in mouse uterine tissues in pregnancy Day 0 through Day 5 were analyzed. RESULTS: Immunoreactive TN and TN mRNA were expressed in the basement membrane of the epithelium as well as in the smooth muscle layer, and their distribution shifted from the subbasement region on Day 0-3 to the smooth muscle layer on Days 4 and 5. CONCLUSIONS: These results indicate that TN expression in the uterus during early pregnancy is spatiotemporally different and may be regulated by a different mechanism.

Animals↗
PubMed1997

Differential expression of tenascin-C and tenascin-X in human astrocytomas.

Tenascins (TNs) are a family of extracellular matrix glycoproteins. The first member of this family to be recognized, tenascin-C (TN-C), is known to be expressed in various tumors including human astrocytomas. Tenascin-X (TN-X) is the latest member of the TN family to be reported, and its expression in tumor tissues has not yet been examined. In this study, we found expression of TN-X in glioma cell lines and human astrocytomas by immunoblot analysis using anti-mouse TN-X antibodies. We also examined the expression of TN-C and TN-X immunohistochemically in a series of 32 human astrocytomas and tissue from 5 normal brains. Expression of TN-X was up-regulated to a higher degree in low-grade astrocytomas than in high-grade astrocytomas. TN-X was mainly localized in the perivascular stroma around tumor vessels, and weakly expressed in the intercellular spaces among tumor cells. In contrast, TN-C was more strongly expressed in the intercellular spaces and in tumor vessels in high-grade astrocytomas (anaplastic astrocytomas and glioblastomas) than in low-grade astrocytomas. In the tissues expressing both TNs, the distribution of TN-X was often reciprocal to that of TN-C. These findings indicate that the expression of TN-C and TN-X in astrocytomas is different, and that these glycoproteins could be involved in neovascularization in different manners.

Animals↗
PubMed1997

The specific expression of tenascin in the synovial membrane of the temporomandibular joint with internal derangement: an immunohistochemical study.

The expression of tenascin (TN) in the tempormandibular joint (TMJ) disc and synovial membrane was examined in 18 human TMJ samples from patients with internal derangement of the TMJ and ten control specimens by an immunohistological technique using paraffin-embedded tissue and specific anti-human TN monoclonal antibody (RCB-1). The expression of TN was observed in all 28 samples, but it was limited to the walls of blood vessels, the perineurium, and the surface of the TMJ disc. The expression of TN was diffuse in the stroma of mildly hypertrophic synovial membranes and focal in the surface of severely hypertrophic synovial membranes. The clinical symptoms of internal derangement of the TMJ are thought to be related to the degree of synovitis. The present study demonstrates that TN is expressed specifically in the portion of the TMJ synovial membrane affected with internal derangement.

Adult↗
PubMed1997

Analysis of tenascin mRNA expression in the murine mammary gland from embryogenesis to carcinogenesis: an in situ hybridization study.

The expression of tenascin gene during murine mammary gland development was analyzed by in situ hybridization with non-radioactive cRNA probes. The aim was to identify whether cells that synthesize tenascin are mesenchymal or epithelial. During embryogenesis, tenascin mRNAs were demonstrated in the epithelial cells of the mammary bud on the 14th and 15th day of gestation, and in the mesenchymal cells from the 14th day to the 17th day, at the epithelial-mesenchymal border of the growing bud. However, cells displaying tenascin mRNAs were not found beyond the bifurcation of the mammary sprout at the beginning of the branching morphogenesis. In post-natal development, tenascin mRNAs were demonstrated in mesenchymal cells surrounding end buds in juvenile mice, in mesenchymal cells surrounding the epithelial cells of plaques, in epithelial cells of the lactating mammary gland, in malignant epithelial cells and in the mesenchymal cells surrounding cancer nests. By immunohistochemistry, tenascin immunoreactivity was shown to have the same spatiotemporal distribution as that of tenascin mRNAs, but was observed to be restricted to the stroma, except in the lactating mammary gland where tenascin was demonstrated in the milk by Western blot. The present study thus showed that both epithelial and mesenchymal cells are sources of tenascin at different stages of murine mammary gland development.

Animals↗