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Biomedical subjects

M Imamura

Publications and source records attributed to M Imamura.

At least 613 records · Page 34Linked to original sources
PubMed1991

Establishment and characterization of a plasma cell leukaemia cell line dependent for growth on IL-6 and a bi-phenotypic subclone dependent upon both IL-3 and IL-6.

A human plasma cell leukaemia cell line (HSM-2) and a subclone (HSM-2.3) have been established from the bone marrow of a patient with bi-phenotypic leukaemia. Proliferation assays using a variety of cytokines demonstrated that HSM-2 proliferated in response to recombinant interleukin-6 (rIL-6), but did not respond to rIL-1, rIL-2, rIL-3, rIL-4, rIL-5, recombinant granulocyte-colony stimulating factor (rG-CSF), or recombinant granulocyte-macrophage-colony stimulating factor (rGM-CSF), and that HSM-2.3 responded to rIL-3 and rIL-6. HSM-2 expressed the CD38 (OKT10), PCA-1, cytoplasmic-IgM, and surface kappa light chain. HSM-2.3 expressed the CD14 (My4), CD33 (My9), CD38 (OKT10), CD19 (B4), CD24 (OKB2), CD10 (J5), PCA-1. HSM-2 and HSM-2.3 are useful tools for analysing the possible role of IL-3 and IL-6 in the oncogenesis of plasma cell leukaemia.

Aged↗
PubMed1991

Alimentary tract reconstruction following pancreatoduodenectomy: a new method with improvements in the nutritional state and gastrointestinal hormone release in dogs.

Experiments were performed on adult beagle dogs to investigate the nutritional state and the release of gastrointestinal hormones after pancreatoduodenectomy. A new variation of reconstruction of the alimentary tract was devised and compared with the classical Child's method. In our method, the remaining stomach was anastomosed to the oral stump of the jejunum in an end-to-end fashion. A short mid-intestinal segment was interposed between the pancreatic and bile ducts and the upper jejunum. During the observation period of six months after surgery, the loss of body weight was significantly smaller in the new method, and the frequency of both morbidity and mortality was lower. Although perforated stomal ulcer was observed in one dog after the Child's method, no peptic ulcer was detectable after our method. The integrated increase of plasma triglyceride in response to ingested butter was slightly greater in our method than in the Child's. At six weeks after surgery, plasma concentrations of both cholecystokinin and secretin, not only during fasting but after intake of butter, were augmented in both groups, particularly in the group receiving the new method. These results indicate that retaining the remaining upper small intestine as the food pathway is effective in maintaining good nutritional state, and in facilitating the release of gastrointestinal hormones.

Animals↗
PubMed1991

[Protein-free culture of esophageal cancer cell lines].

We have established 13 esophageal cancer cell lines capable of growing in a protein-free environment. The growth of these cells was not affected by conditioned medium, but the growth of NIH3T3 cells and human fibroblasts was stimulated by conditioned medium. On the other hand, conditioned medium inhibited the growth of human endothelial cells. Amplified int-2 oncogene correlated well with the growth of cells in a protein-free environment but the number of EGF receptors and growth effect of EGF did not relate to such growth. Esophageal cancer cells grow automatically, possibly involving mesenchymal cells via the paracrine system. This results in a poor prognosis in patients.

Cell Division↗
PubMed1991

[Therapeutic effect of ranimustine(MCNU) on myeloproliferative disorder and chronic myelomonocytic leukemia].

Seventeen patients with myeloproliferative disorders and one patient with chronic myelomonocytic leukemia (CMMoL) were treated with ranimustine++ (MCNU), and the efficacy was evaluated. MCNU was given intravenously by drip infusion at an usual dose of 100 approximately 150 mg with intervals arranged according to the counts of peripheral blood cells. A complete remission was achieved in all 10 patients with chronic myelogenous leukemia (CML) in chronic phase. In three of patients with polycythemia vera (PV) the excellent effects were obtained, and the other 2 cases showed moderate effect. An excellent effect was obtained in both 2 patients with essential thrombocythemia (ET). A patient with CMMoL revealed partial remission. The overall efficacy rate was 100%. The cases with CML needed more long term and much more dose of the drug in order to get remission compared with PV and ET. After remission in both PV and ET, well controlled states were maintained for a relatively long period with no additional administration. In CMMoL, MCNU combined with 6-mercaptopurine also showed remarkable anti-tumor effects. It suggests that MCNU may be one of the useful drugs for the treatment of CMMoL. The side effects observed with MCNU were a slight degree of nausea and vomiting (28%), however they showed no trouble on carrying out the therapy.

Adult↗
PubMed1991

[The control of GVHD and immunodeficiency].

Graft-versus-host disease (GVHD) is caused by the disorder of self-tolerance mechanisms in the thymus and of peripheral tolerance mechanisms. Several cytokines also modulate GVHD, thus inducing complicated clinical features; therefore, it is important to determine which cytokines are mainly involved in the induction of GVHD in order to suppress the production of such cytokines for controlling GVHD. GVHD is closely related to immunodeficiency through T cell and B cell dysfunction. Although cytokines can potentiate these immunological dysfunction, GVHD may be simultaneously augmented by exogenous administration of cytokines. On the contrary, cytokines regulate hematopoiesis as well. Therefore, we should analyze the kinetics of cytokines and their receptor expressions as well as the influences of these factors on immune system and hematopoiesis to control GVHD and immunodeficiency.

Bone Marrow Transplantation↗
PubMed1990

[Comparison of endoscopic ultrasonography and computed tomography in detecting mediastinal and hilar lymph nodes from bronchogenic carcinoma].

We investigated and compared the ability to diagnose metastasis of lung cancer to the mediastinum and hilar lymph nodes using CT and EUS (endoscopic ultrasonography by radial scanning method) in 27 patients undergoing resection of primary lung cancer and 6 autopsy cases. We also determined the relationship between the presence or absence of metastasis and the size of each lymph node based on the lymph node size measured at the time of resection and its histopathological findings, and we then set up a standard value that was the most accurate in evaluating the presence or absence of metastasis using a receiver operating characteristic (ROC) curve. When lymph node sizes appearing as images were compared with their actual sizes measured on resected specimens before formalin fixation, the short axis measured by either method was found to generally agree with the actual values, while the long axis was slightly smaller than the actual values, although EUS gave more accurate values. When the ability to diagnose metastasis was compared between CT and EUS using the standard value obtained from the ROC curve (a more than 8 mm short axis was defined as positive for metastasis), there were no differences in the ability to delineate the entire area of the mediastinum, including hilar lymph nodes. With respect to individual sites, although there was some difficulty delineating some regions in the mediastinum (pretracheal lymph node) with EUS, more lymph nodes in the mediastinum that were delineated by EUS histopathologically had metastatic lesions than those delineated by CT. However, both methods often failed to delineate hilar lymph nodes, with no difference shown between these two methods.

Adult↗
PubMed1990

Transcriptional down-regulation of the rearranged C-myc expression in murine cell hybrids between a plasmacytoma and a T-cell lymphoma.

Regulation of the rearranged and non-rearranged c-myc expression was studied in murine cell hybrids (SBWI and SBWII) between plasmacytoma (S194) and T-cell lymphoma (BW5147) cells. Expression of the rearranged c-myc of heterogeneous mRNA sizes (1.8 approximately 2.4 kb) was markedly down-regulated in these hybrids regardless of retention of the gene. On the other hand, expression of the non-rearranged c-myc (2.4 kb) was not significantly affected in these hybrids. Treatment of SBWI hybrid cells with cycloheximide enhanced the non-rearranged c-myc 2- to 4-fold but did not release the down-regulation of the rearranged c-myc at all, suggesting that the down-regulation of the rearranged c-myc in the hybrid cells was mainly at a transcriptional rather than a post-transcriptional level. This was supported by the results of nuclear run-on assay: the high level of run-on transcripts in S194 cells declined in SBWI hybrid cells comparable to the level in BW5147 cells. The rearranged c-myc was hemi-methylated in S194 cells and the pattern was the same in SBWI hybrid cells. Furthermore, down-regulation of the rearranged c-myc in the hybrid was also not restored by treatment with 5-azacytidine (5-AzaC), 12-O-tetradecanoylphorbol-13-acetate (TPA) or forskolin, suggesting no causative involvement of DNA methylation or protein phosphorylation in down-regulation. Higher DNase I sensitivity of the rearranged c-myc in S194 cells decreased to a similar extent to that of the non-rearranged c-myc after cell fusion with BW5147 cells. These results suggest that expression of the rearranged c-myc is down-regulated at the level of transcription in murine cell hybrids between a plasmacytoma and a T-cell lymphoma, probably by changing chromatin configuration around the gene from the open to the closed state.

Animals↗
PubMed1990

Production of monoclonal antibody to human esophageal cancer cell line.

The immunization of Balb/C mice with esophageal cell line KYSE-50 established from poorly-differentiated esophageal squamous cell carcinoma, resulted in obtaining the monoclonal antibody KYMN-28-5. This monoclonal antibody is of the IgM class and recognizes a carbohydrate antigen contained in glycoproteins with molecular weights of 53 and 56K, and in neutral glycolipids extracted from teratomas. Tissue staining revealed that this monoclonal antibody reacts strongly with malignant tumors but only weakly, or not at all, with normal tissues, apart from squamous epithelial tissue. KYMN-28-5 is thus a useful tumor marker which will improved the accuracy of serological diagnosing squamous cell carcinoma when combined with the measurement of SCC antigen.

Animals↗
PubMed1990

In vivo administration of cytokine in allogeneic bone marrow chimeras.

When we analyzed the in vivo efficacy of cytokine administration in murine allogeneic bone marrow chimeras, mitogen-induced responses to ConA, PHA, LPS, or PWM were increased by the in vivo administration of human recombinant granulocyte colony-stimulating factor (rG-CSF), human recombinant interleukin 2 (rIL-2), or WEHI-3B conditioned medium (CM). Furthermore, we found increased alloreactive mixed lymphocyte reactions (MLRs) against donor and/or host type alloantigens in spleen cells from (BALB/c----C3H/He) chimeras, although cytotoxic activity against BALB/c or C3H/He target cells was not detected in spleen cells from these chimeras. Since no significant increase of T cells or Ia positive cells was observed, some functional activation, rather than changes in the cell count, appeared to relate to increase immunoreactivity. An increased IL-2 production in spleen cells from chimeras injected with cytokine was observed shortly after the cessation of cytokine administration. Thereafter, an IL-2 production in these chimeras decreased around 45 days after bone marrow transplantation and then recovered nearly to the control level. An increased IL-2 responsiveness was also observed in spleen cells from these chimeras. These findings suggest that the in vivo administration of rG-CSF as well as rIL-2 or WEHI-3B CM (IL-3) can modulate the immunoreactivity in chimeras via the network of immune systems.

Animals↗
PubMed1990

Differential distribution of subsets of myofibrillar proteins in cardiac nonstriated and striated myofibrils.

Cultured cardiac myocytes were stained with antibodies to sarcomeric alpha-actinin, troponin-I, alpha-actin, myosin heavy chain (MHC), titin, myomesin, C-protein, and vinculin. Attention was focused on the distribution of these proteins with respect to nonstriated myofibrils (NSMFs) and striated myofibrils (SMFs). In NSMFs, alpha-actinin is found as longitudinally aligned, irregular approximately 0.3-microns aggregates. Such aggregates are associated with alpha-actin, troponin-I, and titin. These I-Z-I-like complexes are also found as ectopic patches outside the domain of myofibrils in close apposition to the ventral surface of the cell. MHC is found outside of SMFs in the form of discrete fibrils. The temporal-spatial distribution and accumulation of the MHC-fibrils with respect to the I-Z-I-like complexes varies greatly along the length of the NSMFs. There are numerous instances of I-Z-I-like complexes without associated MHC-fibrils, and also cases of MHC-fibrils located many microns from I-Z-I-like complexes. The transition between the terminal approximately 1.7-microns sarcomere of any given SMF and its distal NSMF-tip is abrupt and is marked by a characteristic narrow alpha-actinin Z-band and vinculin positive adhesion plaque. A titin antibody T20, which localizes to an epitope at the Z-band in SMFs, precisely costains the 0.3-microns alpha-actinin aggregates in ectopic patches and NSMFs. Another titin antibody T1, which in SMFs localizes to an epitope at the A-I junction, typically does not stain ectopic patches and NSMFs. Where detectable, the T1-positive material is adjacent to rather than part of the 0.3-microns alpha-actinin aggregates. Myomesin and C-protein are found only in their characteristic sarcomeric locations (even in just perceptible SMFs). These A-band-associated proteins appear to be absent in ectopic patches and NSMFs.

Actinin↗
PubMed1990

Remodelling of left ventricular after banding of ascending aorta in the rat.

STUDY OBJECTIVE: The aim was to study sequential changes of cardiac performance and structure after banding of ascending aorta. DESIGN: Cardiac performance and structure were examined at days 1 and 3, and weeks 1, 2, and 4 postoperatively (aortic banding or sham). Cardiac function indices were measured before and during volume overload. Passive pressure-volume relationship and cardiac morphology were examined at the end of the experiment. EXPERIMENTAL MATERIAL: 30 aortic banded and 33 age matched, sham operated rats were used for the studies. The animals were anaesthetised, then instrumented for haemodynamic measurements. MEASUREMENTS AND RESULTS: The left ventricular weight and calculated left ventricular wall thickness of banded rats increased significantly as early as one day postoperation, compared with the age matched shams. This increase persisted throughout the follow up period, except at day 3, when the increase in left ventricular weight did not reach statistical significance. Left ventricular wall mass/cavitary volume ratio increased significantly in banded rats at all follow up periods except at day 3. Cardiac index of banded rats at rest was not different from that of shams but showed a transient significant reduction at 3 d postoperative. However, maximum cardiac index produced by acute volume overload was not different between the two groups throughout the follow up period. Simultaneous end diastolic pressure was significantly higher in banded rats on the first postoperative day but not in later follow up. The passive pressure-volume curve at 1 d postoperative revealed that left ventricular volumes were significantly smaller in banded rats than in shams, whereas chamber stiffness constant and volume elasticity (chamber stiffness constant normalised for left ventricular volume) were not different between the two groups throughout the follow up period. CONCLUSIONS: Taken together, these findings suggest that structural change of the left ventricle may play a role in maintaining left ventricular function by shifting the pressure-volume curve leftward in the early period of aortic banding.

Animals↗
PubMed1990

Unresponsiveness of insulinoma cells to secretin: significance of the secretin test in patients with insulinoma.

It is well known that B cells in the pancreas release insulin when stimulated by secretin, but there have been few reports on the response of insulinoma cells to secretin. In five patients with insulinoma, changes in serum immunoreactive insulin (IRI) concentration were measured after the intravenous injection of secretin into the peripheral vein before and after extirpation of the insulinoma. The extirpated insulinomas were cultured and tested for their response to secretin. The rise in serum IRI in response to secretin in patients with insulinoma was significantly slower and smaller than in normal volunteers. After removal of the insulinoma, the response to secretin became prompt and increased with time. Cultured insulinoma cells did not release insulin when stimulated by secretin. Therefore, it is concluded that the response of insulinoma cells to secretin is quite different from that of normal beta cells, and that the function of beta cells in the insulinoma-bearing pancreas is suppressed by the autonomous hypersecretion of insulin by the insulinoma. The extent of the decrease in function of the beta cells in patients with insulinoma can be estimated by the intravenous secretin test. Thus, the secretin test is sometimes useful in the differentiation of hypoglycemia due to insulinoma from that due to beta cell hyperplasia or alimentary hyperinsulinemia.

Adenoma, Islet Cell↗