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Biomedical subjects

Y Niitsu

Publications and source records attributed to Y Niitsu.

At least 55 records · Page 3Linked to original sources
PubMed2000

p16(INK4a) expression begins early in human colon neoplasia and correlates inversely with markers of cell proliferation.

BACKGROUND & AIMS: p16(INK4a) is a cell cycle inhibitor and a major tumor-suppressor protein, but the regulation of p16(INK4a) is poorly understood and the physiologic settings in which it exerts its antiproliferative effects are unknown. A role for p16(INK4a) in intestinal neoplasia is suggested by the observation that the promoter region is methylated in a subset of human colon tumors. We examined the expression of the protein in specimens representing the full spectrum of neoplastic progression in the human colon and determined whether expressing cells showed evidence of cell cycle inhibition. METHODS: We studied p16(INK4a) expression by immunoprecipitation, immunoblotting, reverse-transcription polymerase chain reaction (RT-PCR), immunohistochemistry, and immunofluorescence in matched normal and neoplastic colonic tissue from 70 patients. RESULTS: p16(INK4a) expression was very low in normal mucosa, with staining observed in rare epithelial cells at the base of crypts. A distinctly higher expression was found in 4 of 7 aberrant crypt foci, 32 of 36 adenomas, 18 of 28 primary carcinomas, and 5 of 5 metastatic carcinomas. Within each neoplasm p16(INK4a) staining was heterogeneous, with higher expression commonly seen in areas bordering normal tissue. p16(INK4a) staining correlated inversely with that of Ki67, cyclin A, and the retinoblastoma protein, suggesting that cell cycle progression was inhibited. CONCLUSIONS: These results suggest that p16(INK4a) expression begins in the earliest detectable stages of neoplastic progression in the human colon and exerts a continuous, piecemeal constraint on tumor growth.

Blotting, Western↗
PubMed2000

A study of carboplatin-coated tube for the unresectable cholangiocarcinoma.

Most cases of cholangiocarcinoma have reached an unresectable stage by the time they are discovered despite significant progress of diagnostic modalities. Many of these patients with obstructive jaundice are often treated by biliary drainage using stents to relieve the jaundice. However, the stent patency period is as short as 3 to 9 months because of tumor ingrowth or overgrowth, and mean survival is at most 12 months. Therefore, both continuous relief of obstructive jaundice and local control of the tumor are required in the treatment for advanced cholangiocarcinoma. In this investigation, we developed a new percutaneous transhepatic biliary drainage tube coated with carboplatin (carboplatin-coated tube; CCT). CCT continuously released a fixed amount of carboplatin for 4 weeks and showed an antitumor effect on human cholangiocarcinoma cell line HuCC-T1 in vitro. When CCT was embedded in subcutaneous tumor inoculated in nude mice, a significant reduction of tumor size with no apparent damage to normal adjacent tissue was observed. On the basis of these studies, 5 patients with inoperable cholangiocarcinoma were treated with CCT for 4 weeks. Overall efficacy rate of 5 patients with cholangiocarcinoma was 60% (partial response in 3 and no change in 2). No apparent side effect was observed in these patients. Thus, CCT may provide a new treatment modality for this disease. Randomized controlled trials comparing CCT therapy with palliative stenting are required to confirm these results.

Aged↗
PubMed2000

In vivo gene delivery to tumor cells by transferrin-streptavidin-DNA conjugate.

To target disseminated tumors in vivo, transgenes [beta-galactosidase gene, green fluorescence protein (GFP) gene, herpes simplex virus thymidine kinase (HSV-TK)] were conjugated to transferrin (Tf) by a biotin-streptavidin bridging, which is stoichiometrically controllable, and Tf receptor (Tf-R) affinity chromatography, which selects Tf conjugates with intact receptor bindings sites from reacting with the linker. Tf-beta-galactosidase plasmid conjugate thus constructed was specifically transfected to human erythroleukemia cells (K562) via Tf-R without the aid of any lysosomotropic agents. The transfection efficiency of the conjugate was superior to those of lipofection (1% staining) and retroviral vector (5%) and slightly lower than that of adenovirus (70%). The high level of expression with our conjugate was confirmed using other tumor cells (M7609, TMK-1) whereas in normal diploid cells (HEL), which express low levels of Tf-R, expression was negligible. When GFP gene conjugates were systemically administered through the tail vein to nude mice subcutaneously inoculated with tumor, expression of GFP mRNA was found almost exclusively in tumors and to a much lesser extent in muscles, whereas GFP revealed by fluorescence microscopy was detected only in the former. To exploit a therapeutic applicability of this method, suicide gene therapy using Tf-HSV-TK gene conjugate for massively metastasized k562 tumors in severe combined immune-deficient mice was conducted, and a marked prolongation of survival and significant reduction of tumor burden were confirmed. Thus, this method could also be used for gene therapy to disseminated tumors.

Animals↗
PubMed2000

Synergistic suppressive effect of double transfection of tumor necrosis factor-alpha and interleukin 12 genes on tumorigenicity of Meth-A cells.

Tumor necrosis factor-alpha (TNF-alpha) and interleukin 12 (IL-12), both potent antitumor cytokines, are known to be involved in the host's antitumor immune surveillance in tumor bearers, via different mechanisms. The former enhances the activities of dendritic cells, natural killer / lymphocyte-activated killer (NK / LAK) and cytotoxic T lymphocyte (CTL), while the latter induces Th1-type cellular immunity and enhances the activities of natural killer T (NKT), NK / LAK and CTL. In the present study, in the expectation of synergistic actions of these cytokines in stimulating the host's immune responses, we investigated the feasibility of a cancer vaccine involving double transfection with both genes in a murine model. The expression of major histocompatibility complex (MHC) class I, class II and B7.1 on the surface of the double transfectants was enhanced as revealed by FACS analysis. A significant decrease in tumorigenicity was observed in mice inoculated with the double transfectants. Cytotoxicity assay revealed that the activities of NK / LAK and CTL from spleens of mice bearing the double transfectants were enhanced. The induction of tumor-specific immunity was confirmed by rechallenge with parental Meth-A cells in mice that had rejected the double transfectants. Thus, double transfection of TNF-alpha and IL-12 genes was considered to bring about synergistic suppressive effects on the tumorigenicity of transfectants through the activation of killer cells by produced cytokines and the enhancement of expression of MHC class I, II and B7.1 molecules.

Adenocarcinoma↗
PubMed2000

Autoantibodies against the specific epitope of human tropomyosin(s) detected by a peptide based enzyme immunoassay in sera of patients with ulcerative colitis show antibody dependent cell mediated cytotoxicity against HLA-DPw9 transfected L cells.

BACKGROUND AND AIMS: Recent studies suggest that tropomyosin (TM) may act as a putative autoantigen in ulcerative colitis (UC). Recently, we identified, by computer homology analysis, a specific peptide (HIAEDADRK) in human TM that can bind to HLA-DPw9. The aim of this study was to investigate the presence of autoantibodies against this peptide in UC. METHODS: Antibodies were measured by ELISA with a synthetic peptide in 20 healthy volunteers, 48 patients with UC, 26 with Crohn's disease (CD), eight with primary sclerosing cholangitis (PSC), and six with primary biliary cirrhosis (PBC). The functional significance of antibodies was investigated by antibody dependent cell mediated cytotoxicity (ADCC) against DPw9 transfected L cells using a standard (51)Cr release assay. RESULTS: Optical density values (mean (SD)) of sera from patients with UC (1.40 (0. 52)) and PSC (1.65 (0.12)) were significantly higher than those from healthy volunteers (0.32 (0.28)) (p<0.05), CD (0.50 (0.34)) (p<0.05) and PBC (0.14 (0.09)) (p<0.05). Values in UC decreased with clinical improvement. The ADCC activity of UC sera correlated well with antibody titre against this synthetic peptide. CONCLUSIONS: Anti-TM antibody was detected in UC sera by a specific peptide based ELISA with high reproducibility. This peptide may be an antigenic epitope of TM involved in the immunopathogenesis of UC and, perhaps, PSC.

Adolescent↗
PubMed2000

Activation of cerebral function by CS-932, a functionally selective M1 partial agonist: neurochemical characterization and pharmacological studies.

A newly synthesized agonist for muscarinic acetylcholine (ACh) receptors CS-932, (R)-3-(3-iso-xazoloxy)-1-azabicyclo-[2.2.2]octane hydrochloride, showed a relatively higher affinity for M1 than M2 receptors expressed in Chinese hamster ovary (CHO)-cells in comparison with ACh. CS-932 elevated the intracellular Ca2+ level only in M1-CHO cells, although ACh increased the level in both M1- and M3-CHO cells. CS-932 and ACh reduced forskolin-stimulated accumulation of cAMP in M2-CHO cells by 20% and 80%, respectively. This neurochemical profile of CS-932 indicates that the compound can activate M1-receptor-mediated functions selectively. CS-932 increased firing of cholinoceptive neurons in rat hippocampal slices, and this excitation was antagonized by pirenzepine, but not by AF-DX 116. CS-932 increased awake and decreased slow wave sleep episodes of daytime EEG in free-moving rats. It counteracted scopolamine-induced slow waves in rat cortical EEG. CS-932 also increased the power of alpha- and beta-waves, but decreased delta-wave of the cortical EEG in anesthetized monkeys. It ameliorated scopolamine-induced impairment of working memory in rats. Orally administered CS-932 had the best penetration into the brain among the muscarinic agonists tested and caused the least salivary secretion among the cholinomimetics examined. These results indicate that CS-932 has potential as a cognitive enhancer with fewer side effects in therapy for Alzheimer disease.

Animals↗
PubMed2000

[Future prospect of gene therapy for hereditary tumor].

Gene therapy for hereditary tumor was discussed in two aspects: preventive and therapeutic approaches. A practical approach to prevention is the transfection of a wild type gene into presymptomatic lesions or normal tissue which may potentially give rise to malignant tumor. Preliminary trials of this approach have already been reported by several investigators. Therapeutic approach is much more difficult since metastasis generally occurs simultaneously at multiple sites and no appropriate delivery system for transgenes to target multiple lesions has been so far developed. We have most recently established a method by which transgenes can be specifically delivered to multiple-metastasized tumors via transferrin receptor and found this method to have successful therapeutic effects. The future direction of gene therapy for hereditary tumor was also addressed.

Genetic Therapy↗
PubMed2000

[Pure red cell aplasia induced by clomipramine hydrochloride in a patient with SLE].

A 48-year-old woman, who had been suffering from systemic lupus erythematosus (SLE), developed normochromic normocytic anemia after receiving clomipramine hydrochloride. Her reticulocyte count was low, and a bone marrow aspirate revealed erythroid hypoplasia without involvement of other cell lines. Thus a diagnosis of pure red cell aplasia (PRCA) was made. The anemia gradually resolved following withdrawal of the drug. Although several drugs are known to cause PRCA, this is the first time that clomipramine hydrochloride has been reported to have such an effect. The underlying SLE in this case suggested the possible immunological pathogenesis of drug-induced PRCA.

Antidepressive Agents, Tricyclic↗
PubMed2000

[Sézary syndrome showing a stable clinical course for more than four years after oral administration of etoposide and methotrexate].

A 62-year-old woman was admitted because of leukocytosis, systemic lymph node swelling and erythroderma. Laboratory data disclosed a WBC count of 15,600/microliter (CD4-positive cells: 91%). CD25 and HTLV-1 were negative. A skin biopsy revealed the involvement of T cells. These data and findings were consistent with a diagnosis of Sézary syndrome. Although the patient was treated with 2 courses of CHOP, the leukocyte count did not decrease. We then treated the patient orally with etoposide (25 mg/day) and methotrexate (10 mg/week), and this resulted in reduction of the leukocyte count and lymph node swelling, and amelioration of the erythroderma. As Sézary syndrome is an extremely rare disease, it is worthwhile reporting cases like the present one, where therapy was successful.

Administration, Oral↗
PubMed2000

A case of diffuse large B-cell lymphoma transformed from immunoglobulin A-producing marginal zone B-cell lymphoma.

We present a rare case of diffuse large B-cell lymphoma transformed from immunoglobulin (Ig) A-secreting marginal zone B-cell lymphoma. A 62-year-old woman was admitted to our hospital for examination of a disseminated pulmonary shadow. Gradual swelling of bilateral axilla and right inguinal lymph nodes were noted after admission. Histological examination of the lymph node biopsy specimen revealed the appearance of marginal zone B-cell lymphoma. The surface Ig of lymphoma cells was IgA-kappa, which coincided with the class of monoclonal Ig found in the patient's serum. The lymph node swelling and pulmonary shadow subsided, and the serum IgA level was normalized by 3 courses of systemic chemotherapy. However, after 4 courses of treatment, new tumor lesions at the right chest wall and left arm progressively became apparent. The biopsy specimen of the tumor showed a feature of diffuse large B-cell lymphoma. Despite intensive chemotherapy, the patient died of spreading tumor burden into the central nervous system.

Cell Transformation, Neoplastic↗
PubMed2000

[Retardation of platelet recovery after autologous stem cell transplantation in a patient with acute lymphoblastic leukemia: possible role of decreased thrombopoietin production by bone marrow stromal cells].

A 16-year-old boy was diagnosed as having acute lymphoblastic leukemia and underwent autologous stem cell transplantation at the time of his second complete remission. Retardation of platelet recovery was evident at day 90 (< 5 x 10(4)/microliter), and at day 660 after transplantation the platelet count was 8.5 x 10(4)/microliter. Neutrophils and RBCs showed only slightly retarded recovery. Bone marrow stromal cells, which are thought to play an integral role in megakaryopoiesis, were examined. Although TPO mRNA expression per cell was normal, CFU-F was significantly decreased, resulting in a decrease of total TPO mRNA expression. In contrast, expression of G-CSF mRNA per cell was increased. It was thought that chemotherapy before bone marrow transplantation may have reduced the number of stromal cells, leading to retardation of platelet recovery because of low TPO expression.

Adolescent↗
PubMed2000

[Severe hemolysis and SIADH-like symptoms induced by vincristine in an ALL patient with liver cirrhosis].

An 11-year-old boy was diagnosed as having acute lymphoblastic leukemia (ALL, L1) in 1987 and underwent treatment with an ALL high-risk protocol (prednisolone, vincristine (VCR), daunorubicin, 1-asparaginase), which resulted in complete remission. In 1990 he developed chronic hepatitis C and received interferon therapy. In December 1994, ALL recurred, and the patient was treated with VCR. He subsequently developed severe hemolysis (Hb 12.5 g/dl-->6.8 g/dl) with increases of indirect bilirubin, AST, and LDH. Furthermore, symptoms resembling a syndrome of inappropriate secretion of ADH (SIADH) and DIC developed. Upon incubation of the patient's red blood cells with VCR in vitro, extreme deformity of the cells was observed. These findings suggested that splenomegaly, due to liver cirrhosis which had developed rapidly from chronic hepatitis C while the patient was in an immunosuppressed state induced by anticancer drugs, had trapped the deformed red blood cells and resulted in severe hemolysis. The patient died on the 165th day after admission due to liver failure.

Adolescent↗
PubMed1999

Exposure of cultured primary rat astrocytes to hypoxia results in intracellular glucose depletion and induction of glycolytic enzymes.

Based on the neurotrophic properties of astrocytes in response to ischemia, the current work focuses on the mechanism for cultured astrocytes to adapt to a hypoxic environment. Intracellular glucose levels in primary cultured rat astrocytes exposed to hypoxia fell by 30% within 24 h, in parallel with a decrease in glycogen stores. Glycolytic metabolism was crucial for cell survival during hypoxia, as 2-deoxyglucose resulted in rapid ATP depletion and cell death. The mechanism for maintaining glucose levels under these conditions appeared to be mobilization of glycogen stores, rather than increased extracellular uptake of glucose, as gluconolactone (an inhibitor of beta1-4 amyloglucosidase) induced a rapid fall in cellular ATP in cultures subjected to hypoxia, whereas cytochalasin B was without affect. Addition of cycloheximide diminished the viability of astrocytes in hypoxia, suggesting an obligatory role of de-novo gene expression to respond to hypoxia. Consistently, the results of differential display suggested the induction of glycolytic enzymes, including aldolase A (EC 4.1.2.13), hexokinase II (ATP: D-hexose 6-phosphotransferase, EC 2.7.1.1), and triosephosphate isomerase (EC 5.3.1.1) in the hypoxic culture. Marked induction of these glycolytic enzymes in hypoxic astrocytes was confirmed by Northern blot analysis. These data provide a theoretical basis to understand the ability of astrocytes to tolerate ischemic condition.

Animals↗