Construction of glycosylated myoglobin by reconstitutional method.
An artificial prosthetic group having beta-galactosyl moieties was synthesized and inserted into sperm whale apomyoglobin to successfully afford a glycosylated myoglobin.
Animals↗
Biomedical subjects
Hirokazu Nagai
Publications and source records attributed to Hirokazu Nagai.
Aberrant DNA demethylation in promoter region and aberrant expression of mRNA of PAX4 gene in hematologic malignancies.
The PAX4 gene, a member of the paired box (PAX) gene family, is thought to be involved in regulating the fate of beta-cells in the mammalian pancreas. We observed the aberrant expression of PAX4 mRNA in 10 of 15 hematologic cell lines analyzed by RT-PCR. The restoration of PAX4 gene expression after treatment with the demethylating agent 5-aza-2'-deoxycitidine, as well as bisulfite sequencing analysis, indicated that gene overexpression was caused by DNA demethylation at the promoter region. Such DNA demethylation also was observed in primary lymphoma (20 out of 45 patients) on combined bisulfite restriction assay (COBRA). Forced expression of the PAX4 gene in the HEK293 and SHSY/610 cell lines conferred positive effects on cell growth. This profile of PAX4 thus corresponds to that of a candidate oncogene in hematologic malignancies.
Azacitidine↗
Loss of O6-methylguanine-DNA methyltransferase protein expression is a favorable prognostic marker in diffuse large B-cell lymphoma.
Although aberrant promoter hypermethylation of O6-methylguanine-DNA methyltransferase (MGMT) is a favorable prognostic marker in patients with diffuse large B-cell lymphoma (DLBCL), MGMT protein expression has not been thoroughly examined. The aim of this study was to evaluate the clinical implication of MGMT protein expression and its correlation with promoter hypermethylation of the gene. We investigated MGMT protein expression by immunohistochemical analysis of 63 DLBCL patients who received cyclophosphamide as part of multidrug regimens. In addition, promoter methylation of the MGMT gene was analyzed by a methylation-specific polymerase chain reaction assay, and correlations with chemotherapeutic effect and prognosis were statistically evaluated. Immunohistochemical assay results for MGMT protein were negative in 30.2% of patients with newly diagnosed DLBCL. Immunostaining results were closely correlated with the methylation status of the promoter. Promoter DNA methylation of the gene was not detected in 34 (81.0%) of 42 tumor samples determined to be MGMT-positive DLBCL by immunostaining and was detected in 15 (88.2%) of 17 cases of MGMT-negative DLBCL. Overall survival (OS) and disease-free survival (DFS) rates were significantly higher in MGMT-negative patients than in MGMT-positive patients (5-year OS, 81.3% versus 56.6% [P = .0375]; 5-year DFS, 66.3% versus 39.9% [P = .0121]). The combined rate for complete response (CR) plus unconfirmed CR was significantly higher in MGMT-negative patients (15/19, 79.0%) than in MGMT-positive patients (25/44, 56.8%) (P = .0488). A multivariate analysis showed that absence of MGMT expression was an independent prognostic factor for OS (relative risk, 4.09; P = .0258). Lack of MGMT protein expression is associated with aberrant promoter DNA methylation and appears to be a useful marker for predicting the survival of DLBCL patients.
Adult↗
Transplantation of rat hepatic stem-like (HSL) cells with collagen matrices.
Organ restitution using somatic stem cells is of great clinical interest. Recent advances in the field of tissue engineering have demonstrated that the use of collagen matrices as scaffolds facilitates tissue reconstruction. Here, we examine the efficacy of transplantation of HSL cells, a previously established liver epithelial cell line with a potential for differentiation, using collagen scaffolds. To this end, HSL cells were transplanted into Nagase's analbuminemic rat with spongy or gelatinous type I collagen matrices. Consequently, immunohistochemical analyses and genomic PCR experiments revealed engraftment of the transplanted cells. Furthermore, the levels of serum albumin in recipient rats were found to increase up to 2.5-fold relative to controls after transplantation. These findings suggest that HSL cells are able to differentiate into functional hepatocytes in vivo, and that biodegradable collagen matrices enhance this phenomenon by providing an appropriate microenvironment for hepatocytic repopulation.
Journal Article↗
CD56/NCAM-positive Langerhans cell sarcoma: a clinicopathologic study of 4 cases.
This report concerns the clinicopathologic features of 4 patients with CD56/neural cell adhesion molecule (NCAM)-positive Langerhans cell sarcoma (LCS). Three of the patients were elderly, between 59 and 62 years of age at presentation, and the other was 35 years old. The presenting symptoms included fever, bone pain, and weakness. The patients shared some clinical findings, such as multiorgan involvement of lymph nodes, skin, lung, bone marrow, and spleen. LCS carries a poor prognosis, and 3 of the patients died of the disease within several years of presentation despite multiagent chemotherapy and radiotherapy. Of special interest is that all of the cases showed CD56 expression on the tumor cells in addition to expression of CD1a, S100beta, and langerin, the presence of which suggests derivation from Langerhans cells. For control, CD56 was also examined in 8 cases of Langerhans cell histiocytosis (LCH), a single-system unifocal or multifocal disease, and the results of staining of the tumor cells were negative. Our findings indicated that CD56 may be a clinically relevant biologic marker for predicting an intractable course of Langerhans cell neoplasms, although it is often difficult to draw a definite morphologically-based distinction between LCS and LCH.
Adult↗
[Evaluation of a combination chemotherapy with docetaxel and nedaplatin for patients with oral squamous cell carcinomas].
The purpose of this study was to evaluate the effectiveness and safety of combination chemotherapy with docetaxel (TXT) and nedaplatin (CDGP) for patients with oral squamous cell carcinomas. Eight patients were enrolled in this study (4 men and 4 women, with a mean age of 61.7 years). TXT and CDGP were administered at a dose of 60 mg/m(2) and 70 mg/m(2) by drip infusion for 120 minutes, respectively. Three patients received one more administration 4 weeks after the first one. The locoregional response was evaluated 4 weeks after the final administration of TXT and CDGP. As a result, the locoregional response rate after 1 course was 62.5% including 25.0% of complete response (CR). The response rate after 2 courses was 100.0% with 66.7% of CR. According to Oboshi and Shimosato's classification, histological evaluation of surgical specimens revealed that four cases were Grade IIa, two cases Grade IIb, and two cases Grade IV. The severe adverse events were neutropenia and leukopenia, which were effectively managed with granulocyte colony-stimulating factor (G-CSF). No other severe side effects were recognized. The present study suggested that the combination chemotherapy with TXT and CDGP would be an effective and safe regimen in neo-adjuvant chemotherapy for oral squamous cell carcinomas.
Adult↗
Two-stage distraction osteogenesis for mandibular segmental defect.
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Ameloblastoma↗
Implant-supported edentulous maxillary obturators with milled bar attachments after maxillectomy.
PURPOSE: The purpose of this study was to evaluate the clinical results of implants and milled bar supported edentulous maxillary obturators following the surgical ablation of maxillary tumors. PATIENTS AND METHODS: Seven patients with malignant tumors of the maxilla were studied. All patients underwent partial or total maxillectomy. Implants were installed in the remaining maxilla and milled bar supported obturators were fabricated. Masticatory efficiency, biting abilities, speech function, and changes in the marginal bone level around the implants were evaluated without the prostheses, with the previous prostheses, and with the implant-supported prostheses. RESULTS: All implants were osseointegrated. All patients wore milled bar supported obturators and masticatory and speech functions markedly improved. There was no complication during the follow-up period. CONCLUSIONS: These results suggest that a maxillary obturator supported by milled bar attachments is useful for oral rehabilitation in patients with resected edentulous maxilla.
Aged↗
[Immunopharmacological approach in elucidating the mechanism responsible for allergic inflammation].
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Animals↗
Epimorphin is involved in differentiation of rat hepatic stem-like cells through cell-cell contact.
Epimorphin, a mesenchymal cell surface-associated molecule, is detected on hepatic stellate cells (HSCs) in the liver. Here, we show the involvement of epimorphin in differentiation of rat hepatic stem-like cells (HSLCs) through contact with HSCs. HSLCs, isolated from adult rats, cultured in stellate cell-conditioned medium had no phenotypic and morphological changes, whereas HSLCs co-cultured with HSCs expressed albumin, transferrin, and tyrosine aminotransferase. An anti-epimorphin antibody inhibited hepatocytic differentiation of HSLCs in co-culture. Furthermore, epimorphin induced mRNA expression of albumin, transferrin, tyrosine aminotransferase, and gamma-glutamyl transpeptidase with decrease of c-kit and musashi-1. Morphologically, HSLCs piled up when co-cultured with HSCs, which was dramatically inhibited by an anti-epimorphin antibody. HSLCs contact with epimorphin started piling up, changed their shape from flat to cuboidal, and subsequently developed bile-canaliculi-like structures. In conclusion, epimorphin is a factor that induces differentiation of hepatic stem-like cells through epithelial-mesenchymal cell contact.
Animals↗
Establishment and characterization of a spontaneously immortalized mouse ameloblast-lineage cell line.
Tooth development was cooperatively regulated by the epithelial ameloblasts and mesenchymal odontoblasts. Ameloblasts secrete enamel matrix, critical for enamel formation. While there are several reports about establishment of immortalized ameloblast-like cells by introducing viral oncogene, we tried to establish a spontaneously immortalized ameloblast-lineage cell line, maintaining the cell type specific character, including the ability to induce in vitro bio-mineralization. The established cell line (ameloblast-lineage cell; ALC) maintained the expression of several ameloblast specific genes (Amelogenin, Tuftelin, and Enamelin) in long-term culture. They formed calcified nodules after the induction by medium switching from SMEM to DMEM, having high-level alkaline-phosphatase activity. The size and number of calcified nodule formation were enhanced by TGF-beta treatment. Six weeks after sub-cutaneous implantation of ALC to athymic nude mice, we ectopically observed enamel epithelium like structure formation, chondrogenesis, and calcification. These data indicate that ALC is a useful experimental tool to analyze ameloblast character.
Alkaline Phosphatase↗
Mutations and aberrant DNA methylation of the PROX1 gene in hematologic malignancies.
The homeobox gene PROX1 is related to the Drosophila prospero gene, which is expressed in the developing central nervous system and lens-secreting cone cells. We found that the PROX1 gene had missense and nonsense mutations in 4 of 29 hematologic cell lines analyzed. Decreased mRNA expression was also observed in half of these cell lines by RT-PCR. The restoration of PROX1 gene expression after treatment with the demethylating agent 5-aza-2'-deoxycytidine, as well as bisulfite sequencing analysis, indicated that gene silencing is caused by DNA hypermethylation at intron 1. Such hypermethylation was also seen in primary lymphomas (56.3%, 18/32) in a tumor-specific manner. These findings indicate that the profile of the PROX1 gene corresponds to that of a candidate tumor-suppressor gene.
Azacitidine↗
Vertical alveolar distraction osteogenesis with complications in a reconstructed mandible.
We report here a case of vertical alveolar distraction osteogenesis with many complications that required further surgical interventions. A 54-year-old man underwent mandibular resection followed by iliac bone grafting as the result of large mandibular odontogenic keratocyst. Eleven months later, alveolar vertical distraction osteogenesis was applied to the patient for prosthetic rehabilitation. Fracture of the basal bone occurred in the consolidation period, and the fracture was fixed by the titanium miniplate system. Radiographic examination after completion of distraction osteogenesis confirmed a radiolucent area in half of the distracted area between the basal bone and the transport segment, and when the distractor was removed the radiolucent area was filled with fibrous granulation tissue. The granulation tissue was removed and endosteal implants were inserted together with a bone graft. Ultimately, all implants were osseointegrated, and adequate esthetics and function of the implant-supported prosthesis were achieved.
Alveolar Bone Loss↗
[Combination chemotherapy with nedaplatin and 5-fluorouracil for oral squamous cell carcinomas].
We used a new combination chemotherapy with nedaplatin (CDGP) and 5-fluorouracil (5-FU) in eleven fresh patients with oral squamous cell carcinomas. 5-FU was administered at a dose of 1,000 mg/body by continuous infusion for 24 hours on days 1 to 5. CDGP was administered at a dose of 80 or 100 mg/m2 by drip infusion for 120 minutes on day 5. The response rates of total (1- or 2-course) and 2-course group were 54. 5% and 83.3%, respectively. Adverse drug reactions were limited to two cases of grade 3 toxicity with anorexia. The combination chemotherapy with 5-FU and CDGP in place of cisplatin and 5-FU seemed to play an important role as neo-adjuvant chemotherapy for oral squamous cell carcinomas.
Aged↗
Aberrant DNA methylation of p57(KIP2) gene in the promoter region in lymphoid malignancies of B-cell phenotype.
The cyclin-dependent kinase inhibitor p57(KIP2) is thought to be a potential tumor suppressor gene (TSG). The present study examines this possibility. We found that the expression of p57(KIP2) gene is absent in various hematological cell lines. Exposing cell lines to the DNA demethylating agent 5-aza-2'-deoxycytidine restored p57(KIP2) gene expression. Bisulfite sequencing analysis of its promoter region showed that p57(KIP2) DNA was completely methylated in cell lines that did not express the p57(KIP2) gene. Thus, DNA methylation of its promoter might lead to inactivation of the p57(KIP2) gene. DNA methylation of this region is thought to be an aberrant alteration, since DNA was not methylated in normal peripheral blood mononuclear cells or in reactive lymphadenitis. Methylation-specific polymerase chain reaction analysis found frequent DNA methylation of the p57(KIP2) gene in primary diffuse large B-cell lymphoma (54.9%) and in follicular lymphoma (44.0%), but methylation was infrequent in myelodysplastic syndrome and adult T-cell leukemia (3.0% and 2.0%, respectively). These findings directly indicate that the profile of the p57(KIP2) gene corresponds to that of a TSG.
Cyclin-Dependent Kinase Inhibitor p57↗
Differentiation of liver epithelial (stem-like) cells into hepatocytes induced by coculture with hepatic stellate cells.
The liver is believed to contain stem cells that can differentiate into either hepatocytes or biliary epithelial cells. In the present study, we established a nonhepatocytic epithelial cell line from the normal livers of adult rats. The established cells, designated HSL cells, were immunoreactive against alpha-fetoprotein, but neither albumin nor cytokeratin 19. To demonstrate the differentiation potential of HSL cells in vitro, the cells were cocultured with hepatic stellate cells as a mixture or separately using insert wells. Consequently, although coculture with hepatic stellate cells rendered HSL cells able to produce albumin, the mixed coculture system mimicking the hepatic environment elicited this phenomenon more effectively than the separated coculture system. In conclusion, HSL cells have immature properties and the potential to differentiate into mature cells. Not only the extracellular matrices but also soluble factors, which are produced by hepatic stellate cells, induce this maturation, demonstrating the importance of the hepatic environment for hepatocyte differentiation.
Albumins↗
The MAGE-A1 gene expression is not determined solely by methylation status of the promoter region in hematological malignancies.
Tumor antigens such as MAGE-A1 are aberrantly expressed in many human tumors and could be recognized by CTL. Thus, they could be targets for cancer immunotherapy. It is presently considered that the expression of the MAGE-A1 gene is regulated by methylation of its promoter region. To estimate the possibility of activating the MAGE-A1 gene with demethylating agents with a view toward clinical use, we assessed the methylation status of its CpG-rich promoter by sodium bisulfite mapping both of samples that express the gene and those that do not. Cell lines and samples from patients with hematological malignancies were examined. Surprisingly, the methylation status of the MAGE-A1 gene did not clearly correlate with the expression of the gene. Our results indicate that the MAGE-A1 gene expression is not determined solely by the methylation status of the promoter region in hematological malignancies.
Antigens, Neoplasm↗
Aplastic anaemia with 13q-: a benign subset of bone marrow failure responsive to immunosuppressive therapy.
In an attempt to determine the pathological significance of a long arm deletion of chromosome 13 (13q-) in bone marrow failure syndrome, we reviewed the clinical records of nine patients who were initially diagnosed with aplastic anaemia due to bone marrow hypoplasia without dysplasia. Six patients responded to immunosuppressive therapy and the other three improved with steroids. None of the patients developed acute leukaemia (follow up: 54-129 months) and the estimated 5-year survival was 78%. These findings indicate that pancytopenia with 13q- represents bone marrow failure of a benign nature, similar to aplastic anaemia without karyotypic abnormalities, rather than preleukaemia.
Adult↗