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Biomedical subjects

Y Niitsu

Publications and source records attributed to Y Niitsu.

At least 19 recordsLinked to original sources
PubMed1996

Hepatic iron deprivation prevents spontaneous development of fulminant hepatitis and liver cancer in Long-Evans Cinnamon rats.

Several clinical studies have suggested that excess hepatic iron accumulation is a progressive factor in some liver diseases including chronic viral hepatitis and hemochromatosis. However, it is not known whether iron-induced hepatotoxicity may be directly involved in hepatitis, cirrhosis, and liver cancer. The Long-Evans Cinnamon (LEC) rat, which accumulates excess copper in the liver as in patients with Wilson's disease, is of a mutant strain displaying spontaneous hemolysis, hepatitis, and liver cancer. We found previously that LEC rats harbored an additional abnormality: accumulation of as much iron as copper in the liver. In the present study, we compared the occurrence of hepatitis and liver cancer in LEC rats fed an iron-deficient diet (ID) with those in rats fed a regular diet (RD). The RD group showed rapid increments of hepatic iron concentrations as the result of hemolysis, characteristics of fulminant hepatitis showing apoptosis, and a 53% mortality rate. However, no rats in the ID group died of fulminant hepatitis. Hepatic iron, especially "free" iron concentration and the extent of hepatic fibrosis in the ID group were far less than those of the RD group. At week 65, all rats in the RD group developed liver cancer, whereas none did in the ID group. These results suggest that the accumulation of iron, possibly by virtue of synergistic radical formation with copper, plays an essential role in the development of fulminant hepatitis, hepatic fibrosis, and subsequent hepatocarcinogenesis in LEC rats.

Animals↗
PubMed1996

Transfection of glutathione S-transferase (GST)-pi antisense complementary DNA increases the sensitivity of a colon cancer cell line to adriamycin, cisplatin, melphalan, and etoposide.

The goal of this study was to demonstrate that glutathione S-transferase (GST)-pi is directly involved in the intrinsic and acquired resistance of cancer cells to anticancer drugs. To this end, GST-pi antisense cDNA was transfected into the cultured human colon cancer cell line M7609, which expresses an innately high level of GST-pi and shows intrinsic drug resistance, and into an M7609 strain with acquired resistance to Adriamycin (ADR;i.e., M7609/ADR cells). The changes in the sensitivity of these transfectants to various anticancer drugs were investigated. The intracellular concentrations of GST-pi in M7609/anti-1 cells and M7609/anti-2 cells, two clones that were established by transfection of GST-pi antisense cDNA into M7609 cells, were decreased to approximately half of those detected in the parent cells (M7609) and in the control cells transfected with vector alone (M7609/pLJ). The sensitivities of the antisense transfectants in relation to ADR, cisplatin, melphalan, and etoposide were increased -3.3-fold, 2.3-fold, 2.2-fold, and 2.1-fold, respectively, compared with those of M7609 and M7609/pLJ. On the other hand, the sensitivities of the antisense transfectants to Taxol, vincristine, 5-fluorouracil, and mitomycin C were not significantly changed. Similarly, the transfection of antisense cDNA into M7609/ADR cells resulted in the reduction of intracellular GST-pi concentration (by about half) and an increased sensitivity to ADR (4.4-fold), but no increase in 5-fluorouracil sensitivity. Thus, GST-pi is considered to be a multidrug resistance factor that is responsible for both the intrinsic and acquired resistance of cancer cells to anticancer drugs such as ADR, cisplatin, melphalan, and etoposide.

Antineoplastic Agents↗
PubMed1996

Glutathione S-transferase-pi is secreted as a monomer into human plasma by platelets and tumor cells.

By employing an ELISA for detection of glutathione S-transferase-pi (GST-pi) established in our laboratory, gel filtration profiles of GST-pi in the plasma of normal subjects and patients with malignant tumors were investigated. The results showed that the plasma GST-pi for both of these groups was approximately half the molecular size of placental GST-pi used as a standard control. Similar analyses were performed on GST-pi of platelets and cultured cancer cells, which are considered to be the main sources of the GST-pi in the plasma of normal subjects and cancer patients, respectively. The results indicated that the GST-pi in both the centrifuged supernatants of aggregated platelets and in the culture medium of cancer cells was about half of the molecular size on intact GST-pi. Moreover, the GST-pi in the culture medium was shown to have an N-terminus and a C-terminus, by analysis with specific ELISA. Western blot analysis of the GST-pi in the culture medium detected a single band migrating at 23 kDa, confirming that the extracellular GST-pi was the monomer, not a cleaved form of intact GST-pi. The release of GST-pi from cancer cells was suppressed at 4 degrees C, or by sodium azide, but not suppressed by colchicine or cytochalasin B. These findings suggest that GST-pi may be released by an energy-dependent, active process, and not by a secretion mechanism.

Blood Platelets↗
PubMed1996

Establishment of high- and low-invasion clones derived for a human tongue squamous-cell carcinoma cell line SAS.

Distant-organ metastasis and regional lymph node metastasis are still the major cause of mortality of oral-cavity squamous-cell cancer (SCC). However, only a few studies have been undertaken to elucidate the mechanism of invasion and metastasis of oral SCC. In this study, we attempted to establish human oral SCC clones with different invasiveness, defined by endothelial cell monolayer assay, which can be used for the study of invasion and metastasis of oral SCC. We established five clones from the human oral SCC cell line SAS by a limiting-dilution method. Two distinct clones, SAS-L1 with very low invasive potential and SAS-H1 with very high invasive potential, were picked out by rat lung endothelial cell monolayer assay. The number of SAS-H1 that penetrated the rat lung endothelial cell monolayer was six fold higher than the number of SAS-L1. There were no differences of metalloproteinase production and cell adhesiveness to Matrigel of SAS-L1 and SAS-H1. However, SAS-H1 exhibited a higher migration ability than SAS-L1. This pair of clones would be a useful experimental model to help in the study of the invasiveness of human oral SCC.

Basement Membrane↗
PubMed1996

Determining depth of invasion of advanced colorectal cancer using MRI short inversion time inversion recovery sequences.

To examine the usefulness of magnetic resonance imaging (MRI) in the preoperative determination of cancerous invasion, we examined 39 patients with advanced colorectal cancer with 0.5T MRI. We employed short inversion time inversion recovery (STIR) sequences, in addition to ordinary spin echo sequences for T1- and T2-weighted images. Preoperatively, the estimated depth of tumor invasion was classified into three grades according to MRI findings, and confirmed on the basis of surgical and histopathologic results. The depth of tumor invasion estimated preoperatively using STIR sequences corresponded well with the surgical and histopathologic results in 85% of the cases. In contrast, assessments based on T1-weighted images corresponded well in only 62% of the cases and T2-weighted images corresponded well in only 64%.

Colon, Sigmoid↗
PubMed1996

Analysis of CA repeats in first intron of class I ADH gene in Long-Evans Cinnamon rats developing fatal intoxication after ethanol intake.

The Long-Evans Cinnamon (LEC) rat is a mutant strain established from Long-Evans rats that displays spontaneous hepatitis and liver cancer. We previously demonstrated that LEC rats died of acute ethanol intoxication after being fed a liquid diet containing 5% ethanol. Furthermore, we found that both alcohol dehydrogenase (ADH) and aldehyde dehydrogenase activities were remarkably suppressed in the liver of LEC rat, compared with Wistar rats. In the present study, we further investigated ethanol metabolism in the non-ADH pathway and what caused the decrease of liver ADH activity in LEC rats. Blood ethanol concentration 5 hr after intraperitoneal administration of ethanol in LEC rats was higher than in the Wistar rats, indicating that ethanol oxidation was impaired in LEC rats. The expression of liver cytochrome P-450IIE1 in the LEC rat was as much as that in Wistar rats. Regarding decreased ADH activity in the liver of LEC rats, we examined an alternating purine-pyrimidine (CA) repeat-length polymorphism in the first intron of a class I ADH gene that would play a role in altering ADH activity. A polymerase chain reaction method was used to amplify the CA repeat in the first intron of this class I ADH gene, a nine CA repeat insertion and a point mutation were detected in LEC rats. These results suggest that this alternating sequence would modify transcription of the class I ADH gene in LEC rats. Thus, LEC rats have abnormal ethanol metabolism in the ADH pathway.

Alcohol Dehydrogenase↗
PubMed1996

Detection of activity in the conditioned medium of ethanol-treated HepG2 cells which stimulates collagen synthesis in IMR-90 cells.

Hepatic fibrosis often occurs in alcoholic liver diseases without accompanying tissue necrosis or inflammation. However, the precise mechanism of this fibrosis has not been fully clarified. In the present study, using the hepatoblastoma cell line HepG2 as a model for hepatocytes, we identified a factor that stimulates collagen synthesis of fibroblasts in a conditioned medium of HepG2 cells after treatment with ethanol. Type 1 procollagen peptide (PIC) in a culture of human fibroblast IMR-90 markedly increased after incubation with the conditioned medium of ethanol-treated HepG2 cells. The stimulating activity on the production of PIC by IMR-90 remained after the dialysis and evaporation of the conditioned medium of HepG2 cells, indicating this factor was not as volatile from low molecular substances such as acetaldehyde, acetate, or lactate. The activity of this factor diminished with heat or trypsin treatment. A gel chromatographic analysis disclosed that the molecular weight of this factor was approximately 8000 Da. These results suggest that a polypeptide factor secreted from HepG2 cells by treatment with ethanol stimulates collagen synthesis of fibroblasts.

Carcinoma, Hepatocellular↗
PubMed1996

Tumor necrosis factor and interferon-gamma augment anticolon antibody- dependent cellular cytotoxicity in ulcerative colitis.

The effect of tumor necrosis factor (TNF) and interferon (IFN)-gamma on antibody-dependent cellular cytotoxicity (ADCC) in patients with ulcerative colitis (UC) was investigated. ADCC activity was measured by the 51Cr release assay, using peripheral blood mononuclear cells of healthy subjects as effector cells and RPMI 4788 cells derived from human colon cancer as target cells. ADCC activity under sera from healty subjects remained low whether or not the effector cells were pretreated with TNF (100 U/ml, 16h). Under sera from UC patients, ADCC activity of 13.9%, compared to 9.6% when pretreatment was deleted. The effect of IFN pretreatment (100 U/ml, 16h) was also examined under sera from UC patients; in that experiment activity rose to 26.8%, in comparison to a 10.7% when IFN-gamma pretreatment was deleted. Finally, when the effector cells were pretreated with both TNF and IFN-gamma (100 U/ml of each, 16h) the ADCC activity under sera from UC patients was higher than when either TNF or IFN-gamma were used alone. These results suggest that TNF and IFN-gamma, by increasing ADCC activity in UC lesions, are involved in cell injury in the colonic epithelium. IFN-gamma appears to increase ADCC activity by increasing the number of high affinity monocyte Fc gamma RI receptors, while TNF increases ADCC activity by a different mechanism.

Adjuvants, Immunologic↗
PubMed1996

[Gene therapy for cancer].

The strategies of gene therapy for cancer can be classified as: 1. regulation of oncogenes and anti-oncogenes, 2. immunogenetherapy, 3. support of chemotherapy, 4. suicide gene therapy, and 5. gene marking. The first one is the strategy to inhibit the expression of oncogenes by their antisenses or rhybozymes, or to introduce anti-oncogenes into those tumor cells with the inactivate effector cells (lymphocytes) by transducing cytokine genes, etc., followed by retransfering the gene-modified effector cells to patients (adoptive immunotherapy). The other one is to augment antigenicity of tumor cells. The immunogenetherapy method has been widely used for 70% of gene therapy of human cancer, because cells can be transduced ex vivo. The anti-tumor effects of human gene therapy using a GM-CSF gene by Muligan et al. or an IL-2 gene by Tahara and Lotze are expected. The third is the strategy to protect bone marrows from large dose of anti-cancer drug by transducing a multidrug resistance gene into those bone marrow cells or periphen blood stem cells, overcoming dose limiting of the drug. The fourth strategy is to transduce the herpes simplex virus thymidine kinase (KSV-TK) gene for activating the cytocydal prodrug (ganciclovir: GCV) into tumor cells in order to kill the tumor cells themselves following administration of GCV. At present, vectors most widely used for gene transduction are retroviruses and adenoviruses. However, the transduction using these vectors are primarily conducted ex vivo. The direct in vivo gene delivery method to target tumor cells are required.

Cytokines↗
PubMed1996

[CD7, HLA-DR, CD38 positive acute undifferentiated leukemia with subcutaneous tumor and thymoma].

A case of acute undifferentiated leukemia (AUL), accompanied by subcutaneous tumor and thymoma is reported. The analysis of immunophenotype showed that the leukemic blasts were positive for CD7, HLA-DR, CD38 and CD34 in 17.5% but negative results were obtained for other lymphoid and myeloid antigens. The leukemic blasts had a rearranged immunoglobulin heavy chain (IgH) gene and T cell receptor delta (TCR-delta) chain gene chromosomal abnormality, 47, XY, +8, t(13; 17) (q12; q21), -17, +M was observed. In general, the CR rate is low and prognosis is poor in patients with AUL. In our case, CR was not achieved by the therapy with JALSG-ALL87 protocol, but was achieved by subsequent treatment with high dose ara-C therapy and combination chemotherapy including intermediate-dose ara-C, mitoxantrone, etoposide and prednisolone.

ADP-ribosyl Cyclase↗
PubMed1995

Superoxide dismutase in SAS human tongue carcinoma cell line is a factor defining invasiveness and cell motility.

This article describes an apparent inverse relationship between cell motility and intracellular Cu-Zn superoxide dismutase (SOD) activity of two human squamous carcinoma-derived clones, SAS-H1 with high invasiveness and SAS-L1 with low invasiveness. Clone SAS-H1 exhibited significantly greater motility than SAS-L1 but had significantly lower levels of intracellular Cu-ZnSOD than SAS-L1 cells. We then transfected Cu-ZnSOD antisense cDNA into SAS-L1 to reduce the intracellular Cu-ZnSOD activity. Antisense cDNA transfected SAS-L-AS clones had lower Cu-ZnSOD activity than control vector-transfected SAS-L-Neo clones, and this was associated with increased motility. Invasiveness of SAS-H1 and SAS-L-AS1 was enhanced by superoxide treatment, while the invasiveness of SAS-L1 was unaffected. These findings indicate that intracellular SOD is involved in cell motility by virtue of its action in scavenging superoxide in the cells.

Base Sequence↗
PubMed1995

Regulation of synapse density by 5-HT2A receptor agonist and antagonist in the spinal cord of chicken embryo.

Identification of mechanisms that regulate the number of synapses in the brain has been a key issue for understanding the mechanism of plasticity. Here, we report that the density of synapses can be changed using an antagonist and/or an agonist of serotonin (5-HT) type 2A receptors in the chicken spinal cord. Because of the widespread distribution pattern of 5-HT fibers and 5-HT2A receptors in the central nervous system, 5-HT is thought to play a role in the formation and maintenance of synapses that are involved in normal brain function and mechanism of plasticity.

Amphetamines↗
PubMed1995

Combination therapy with recombinant human granulocyte colony-stimulating factor and erythropoietin in aplastic anemia.

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) and erythropoietin (rhEPO) were used to treat patients with aplastic anemia (AA). In terms of effects on erythrocyte recovery, the combined use of rhG-CSF and rhEPO showed a favorable response in 6 of 14 (42.9%) patients with moderate AA following 10 weeks treatment and in 3 of 14 (21.4%) patients thereafter. However, the response was poor in patients with severe AA (3/13). A favorable response in severe AA was observed in 1 of 13 (7.7%) patients following 10 weeks treatment and in 2 of 13 (15.4%) patients thereafter. The overall effect on erythrocytes was observed in 44.4% patients. A dose of 400 micrograms/m2 G-CSF was sufficient to cause an increase in neutrophil count and 100 IU/kg rhEPO appeared to be sufficient to cause an increase in erythrocyte count. In 6 of 27 (22.2%) patients, a trilineage response was observed. Interestingly, a delayed and long-lasting effect was obtained in 5 of 27 (18.5%) patients. These results suggest that rhG-CSF can synergize with rhEPO in erythrocyte response, especially in patients with moderate AA.

Adult↗
PubMed1995

Characterization of tumor-necrosis-factor-gene-transduced tumor-infiltrating lymphocytes from ascitic fluid of cancer patients: analysis of cytolytic activity, growth rate, adhesion molecule expression and cytokine production.

We characterized tumor-infiltrating lymphocytes (TIL) from ascites of patients with ovarian or pancreatic cancer in which the human tumor necrosis factor (TNF) gene was successfully transduced with retrovirus vector. The TNF-gene-transduced TIL (TNF-TIL) from these patients showed a higher level of TNF production and higher cytotoxic activity against K562 and Daudi cells than did neomycin-phosphotransferase-gene-transduced TIL (neo-TIL). Of these TIL preparations, only that from pancreatic cancer was further characterized since it was collected in a relatively large amount. In spite of the fact that the autologous tumor cells showed resistance to soluble TNF, the TNF-TIL clearly demonstrated enhanced cytotoxicity against them as compared with neo-TIL. The enhanced cytotoxicity was ascribed to autocrine effects of secreted TNF on TIL, which included augmentation of adhesion molecule (CD2 and CD11a) and interleukin-2 receptor expression, and elevation of production of interferon gamma, lymphotoxin and granulocyte/macrophage-colony-stimulating factor and its paracrine effect on target cells to facilitate them to be more susceptible to TIL.

Ascites↗
PubMed1995

Co-administration of IL3 with G-CSF increases the CFU-S mobilization into peripheral blood.

In an attempt to establish an efficient method of collecting peripheral blood stem cells and to utilize them for allogeneic peripheral blood stem cell transplantation, the effect of a combined administration of recombinant murine interleukin-3 (IL3) and recombinant human granulocyte colony-stimulating factor (G-CSF) to mobilize bone marrow stem cells into the circulation was examined in C57BL/6 mice. Some appreciable numbers (796 +/- 112/ml) of CFU-GM were recovered 6 days after G-CSF administration (500 micrograms/kg per day), while by IL3 administration (100,000 units/kg per day), the CFU-GM count was much lower (61 +/- 9/ml) with a small peak at day 4. By a combined administration of IL3 (100,000 units/kg per day) and G-CSF (500 micrograms/kg per day), the CFU-GM count at the peak of day 5 was significantly augmented (1178 +/- 277/ml) as compared to that of G-CSF or IL3 alone (P < 0.05). The CFU-S counts at day 5 (168 +/- 12/ml) and at day 6 (172 +/- 27) were also significantly higher than those of IL3 alone (day 5, 30 +/- 15/ml; day 6, 20 +/- 10/ml) or G-CSF alone (day 5, 114 +/- 14/ml; day 6, 112 +/- 19/ml). Thus the combined administration of IL3 and G-CSF appears to be promising for high yield collection of peripheral blood stem cells.

Animals↗
PubMed1995

T-cell mediated polyclonal B-cell activation in a case of B-cell lymphoma associated with polyclonal hypergammaglobulinemia.

The mechanism of abnormal immunoglobulin production in non-Hodgkin's lymphoma is still poorly understood. We report a case of B-cell type non-Hodgkin's lymphoma associated with marked elevated polyclonal hyper-gammaglobulinemia (serum IgG was 7598 mg/dl; IgM, 455 mg/dl). We conducted a mixed lymphocyte culture test using peripheral lymphocytes obtained from the patient and a healthy volunteer. After co-culture with the patient's CD3+ cells, not only the patient's CD3- cells but also control CD3- cells produced greater amounts of IgG and IgM. Elevated IL-6 was also detected from the patient's CD3+ cells. This strongly suggests that B-lymphoma cells stimulate CD3+ cells to produce IL-6 and hence activate normal CD3- cells.

B-Lymphocytes↗