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Biomedical subjects

Y Niitsu

Publications and source records attributed to Y Niitsu.

At least 73 records · Page 4Linked to original sources
PubMed1999

Transforming growth factor-beta1 (TGF-beta1) induces thrombopoietin from bone marrow stromal cells, which stimulates the expression of TGF-beta receptor on megakaryocytes and, in turn, renders them susceptible to suppression by TGF-beta itself with high specificity.

The present study was designed to test the concept that platelets release a humoral factor that plays a regulatory role in megakaryopoiesis. The results showed that, among various hematoregulatory cytokines examined, transforming growth factor-beta1 (TGF-beta1) was by far the most potent enhancer of mRNA expression of bone marrow stromal thrombopoietin (TPO), a commitment of lineage specificity. The TPO, in turn, induced TGF-beta receptors I and II on megakaryoblasts at the midmegakaryopoietic stage; at this stage, TGF-beta1 was able to arrest the maturation of megakaryocyte colony-forming units (CFU-Meg). This effect was relatively specific when compared with its effect on burst-forming unit-erythroid (BFU-E) or colony-forming unit-granulocyte-macrophage (CFU-GM). In patients with idiopathic thrombocytopenic purpura (ITP), the levels of both TGF-beta1 and stromal TPO mRNA were correlatively increased and an arrest of megakaryocyte maturation was observed. These in vivo findings are in accord with the aforementioned in vitro results. Thus, the results of the present investigation suggest that TGF-beta1 is one of the pathophysiological feedback regulators of megakaryopoiesis.

Bone Marrow↗
PubMed1999

Rheologic analysis of gastric mucosal hemodynamics in patients with cirrhosis.

BACKGROUND: Portal hypertensive gastropathy causes some gastric mucosal microcirculatory disorders in cirrhotic patients, but the nature of the rheologic dysfunction in the gastric microcirculation remains to be clarified. METHODS: To examine the rheologic properties of the gastric microcirculation, we subjected 112 cirrhotic patients and 51 control subjects to endoscopic laser Doppler flowmetry and measured multiple variables of flow, red blood cell volume, and velocity. Furthermore, based on these results, we analyzed the shear rate which reflects the status of the microcirculatory system. To validate the laser Doppler flowmetry, we derived the relationship between red blood cell volume and cross-sectional areas of submucosal collecting venules; near-infrared endoscopy was used to evaluate this relationship. RESULTS: Analysis of shear rate according to the severity of portal hypertensive gastropathy showed that the mucosa was exposed to strong hemokinetic stress in severe cases, characterized by a higher shear rate than in control subjects or in mild cases. Nitroglycerin, administered by intravenous infusion (1.0 microg/kg/min), reduced blood flow and restored shear rate to control levels in patients with severe portal hypertensive gastropathy. CONCLUSION: This rheologic study of the gastric mucosa suggests that a disorder of the shear rate control mechanism in the microcirculation is associated with severe portal hypertensive gastropathy.

Endoscopy, Digestive System↗
PubMed1999

Enhanced inhibition of experimental metastasis by the combination chemotherapy of Cu-Zn SOD and adriamycin.

We previously reported that reactive oxygen species (ROS) enhance tumor cell metastasis, and by administration of recombinant human superoxide dismutase (rh SOD), an enzyme which scavenges O2- successfully reduced lung metastasis of mouse MethA sarcoma and Lewis lung carcinoma. These observations suggested that rh SOD suppressed tumor cell invasion by eliminating O2- the primary source of ROS. However, for the clinical application of the drug as an anti metastatic agent, rh SOD needs to be administered in combination with other cytotoxic agents, since SOD by itself has no cytotoxic activity. In this paper, we investigated the effectiveness of the combination chemotherapy of rh SOD and adriamycin (ADR), an anti-cancer agent against the experimental metastasis of highly metastatic clone, MH-02, which was derived from murine Meth A sarcoma. The present metastasis experiment clearly indicates that the administration of rh SOD enhances the antimetastatic effect of ADR. On the other hand, we found that the inhibition rate of metastasis exhibited by the combination chemotherapy of rh SOD and a certain dose (5 mg/ml) of ADR was inferior to that of rh SOD. This apparent paradoxical phenomenon was presumably explained by our finding that tumor cells themselves augment their invasive capacity and platelet aggregation, both of which are causative factors for metastasis formation, by generation of O2- when they were treated with ADR. Nevertheless, the combination chemotherapy of SOD with anticancer drugs such as ADR can be a practical anti-metastasis strategy.

Animals↗
PubMed1999

Induction of transformation and p53-dependent apoptosis by adenovirus type 5 E4orf6/7 cDNA.

Adenovirus (Ad) E4orf6/7, one of the early gene products of human Ads, forms a stable complex with the cellular transcription factor E2F to activate transcription from the Ad E2 promoter. E2F cDNAs have growth-promoting and apoptosis-inducing activities when overexpressed in cells. We cloned Ad5 E4orf6/7 cDNA in both simian virus 40- and human cytomegalovirus-based expression vectors to examine its transforming and apoptotic activities. The cloned E4orf6/7 collaborated with a retinoblastoma protein (RB)-nonbinding and therefore E2F-nonreleasing mutant of Ad5 E1A (dl922/947) to morphologically transform primary rat cells, suggesting that E2F is an important cellular protein functioning downstream of E1A for transformation. In a G418 colony formation assay, E4orf6/7 was shown to suppress growth of untransformed rat cells. Moreover, a recombinant Ad expressing Ad5 E4orf6/7 induced apoptosis in rat cells when coinfected with wild-type p53-expressing Ad. Mutational analysis of E4orf6/7 revealed that both of the domains required for growth inhibition and transformation by E4orf6/7 lay in the C-terminal region, which is essential for transactivation from the upstream sequence of an E2a promoter containing E2F-binding sites. However, the smallest mutant of E4orf6/7, encoding the C-terminal 59 amino acids, failed to complement the RB-nonbinding dl922/947 mutant despite showing growth inhibition and E2F transactivation activities. Thus, it is suggested that a subregion of E4orf6/7 which is required for growth inhibition and transformation in collaboration with dl922/947 overlaps the transactivation domain of E4orf6/7.

Adenovirus E1A Proteins↗
PubMed1999

Systemic lupus erythematosus with a giant rectal ulcer and perforation.

A 41-year-old man with systemic lupus erythematosus (SLE) who developed pelvic inflammation due to perforation of a giant rectal ulcer is described. The patient presented with persistent diarrhea, abdominal pain and fever without development of disease activity of SLE. Endoscopic and radiological examinations revealed a perforated giant ulcer on the posterior wall at the rectum below the peritoneal evagination. The ulcerated area was decreased after a colostomy was performed at the transverse colon to preserve anal function. The patient is currently being monitored on an outpatient basis. It should be noted that life-threatening complications such as perforated ulcer of the intestinal tract could occur without SLE disease activity.

Adult↗
PubMed1999

Use of PCR serum in diagnosing and monitoring cytomegalovirus reactivation in bone marrow transplant recipients.

We previously reported that the use of polymerase chain reaction (PCR) in detecting cytomegalovirus (CMV) DNA in serum (sPCR) enables the detection of CMV viremia, which has not been possible with other methods. In this study, the clinical usefulness of sPCR was investigated by comparison with the results of three other diagnostic methods, i.e., antigenemia assay (AG), shell vial culture test (shell vial), and complement-fixing (CF) antibody titer. The present study included 26 patients with hematological diseases who had undergone allogeneic bone marrow transplantation (BMT). A total of 347 samples were collected, and the results of the sPCR and AG methods were in agreement in 91.1% of the samples. When a subject was positive in both the sPCR and AG tests, and the other two tests (shell vial and CF) were also positive, CMV reactivation was surmised as definite. When only the result of the shell vial test or the CF test was positive, these results were taken as false-positives. The time at which the samples became positive in each of these four tests was 7.5 weeks post-BMT for sPCR, 7.0 weeks post-BMT for the AG test, 7.4 weeks post-BMT for the shell vial test, and 9.7 weeks post-BMT for the CF test. Thus, it was found that samples became positive at almost the same time for the sPCR, AG, and shell vial tests. Interstitial pneumonitis (IP) due to CMV developed in 3 subjects. These cases were positive in the sPCR, AG, and shell vial tests prior to the manifestation of symptoms of IP. The CF test did not become positive until after the onset of the disease. As the IP due to CMV was controlled with treatment, the sPCR and AG tests became negative. With the shell vial and CF tests, on the other hand, the test results continued to be positive even after the IP was cured. These findings demonstrate that the sPCR test method--like the AG test--yields few false-positive results. Therefore, the sPCR method is useful in early diagnosis of reactivation of CMV and for evaluation of the efficacy of therapy administered for IP. In addition, sPCR can be performed simultaneously on a large number of samples, and the evaluation of the test results is simple. We conclude that the sPCR test may be superior to the three other diagnostic methods for evaluation of serum samples from multiple institutions.

Adolescent↗
PubMed1999

[The advances of gene therapy in this quarter century].

Progress of molecular biological technology has brought about great advances in gene therapy. The establishment of DNA recombination and transfection techniques in 1980s allowed us to utilize gene as therapeutics. Since the initial clinical trial of gene therapy in 1990, over 250 of clinical protocols have been undergone in United States and over two thousand patients have been enrolled in gene therapy in worldwide. First gene therapy protocol was carried out in 1995 and cancer gene therapy was just started last year in our country. The overview of gene therapy in this quarter century was described and also the development of gene therapy related technologies was mentioned in this review.

Animals↗
PubMed1999

A case of malignant lymphoma producing autoantibody against platelet glycoprotein Ib.

A 61-year-old woman was referred to our hospital for refractory thrombocytopenia (3 x 10(3)/microliter) and massive melena. Bone marrow aspiration revealed normal cellularity and increased megakaryocytes (250/microliter). An abdominal computerized axial tomography scan showed isodensity masses on both adrenal glands. 67 Ga-scintigraphy exhibited strong uptake into the bilateral adrenal tumor and mediastinal region. IgM-type antibody against platelet glycoprotein Ib (GpIb) was detected in the patient's serum. A needle biopsy of the right adrenal tumor was performed, and histology was non-Hodgkin's lymphoma (NHL), diffuse large B-cell type. Following the diagnosis of autoimmune thrombocytopenia associated with lymphoma, administration of corticosteroid (predonisolone 60 mg/day) and high-dose intravenous globulin (15 g/day x 4 days) was carried out, but neither was effective in normalizing the thrombocytopenia. Immunosuppressive therapy (cyclophosphamide 500 mg and 1 mg of vincristine) markedly restored the platelet counts to 7.2 x 10(4)/microliter and ceased the melena; furthermore, the size of adrenal tumors decreased by more than 60% after therapy. We cultured the lymphoma cells drawn by needle biopsy with IL-6 in vitro and found that the lymphoma cells produced IgM-type antiplatelet antibodies against platelet GpIb in the culture supernatant. Thus this is a rare case of NHL in which the production of antiplatelet antibody from lymphoma cells was confirmed in vitro.

Autoantibodies↗
PubMed1999

[Waldenström macroglobulinemia with diffuse large B-cell lymphoma that developed from a different B-cell clone].

A 62-year-old man was given a diagnosis of Waldenström macroglobulinemia (WM) in January 1995. He was treated with melphalan and corticosteroid until January 1996, when he experienced high fever and weight loss. The patient visited a nearby hospital, received a diagnosis of liver abscess, and was referred to our hospital on February 23, 1996. Computed axial tomographic scans demonstrated multiple isodensity masses in the liver, left adrenal region, and right kidney hilum. Needle biopsy specimens of a liver mass revealed infiltration of diffuse large B-cell lymphoma (REAL classification), suggesting that non-Hodgkin's lymphoma supervened WM. Despite multiple cycles of chemotherapy, the lymphoma responded poorly. The patient died of pneumonia and sepsis on May 10, 1996 and an autopsy disclosed broad involvement of liver and spleen with lymphoma. Southern blot analysis of DNA samples obtained from the patient's bone marrow at the time of the initial diagnosis of WM, and later from the needle biopsy specimen of liver mass, displayed different patterns of immunoglobulin heavy chain gene rearrangement. We therefore concluded that in this patient the lymphoma was not a progression of WM, but rather, an independent B-cell malignancy.

B-Lymphocytes↗
PubMed1998

Aberrant crypt foci of the colon as precursors of adenoma and cancer.

BACKGROUND: Aberrant crypt foci of the colon are possible precursors of adenoma and cancer, but these lesions have been studied mainly in surgical specimens from patients who already had colon cancer. METHODS: Using magnifying endoscopy, we studied the prevalence, number, size, and dysplastic features of aberrant crypt foci and their distribution according to age in 171 normal subjects, 131 patients with adenoma, and 48 patients with colorectal cancer. We also prospectively examined the prevalence of aberrant crypt foci in 11 subjects (4 normal subjects, 6 with adenoma, and 1 with cancer) before and after the administration of 100 mg of sulindac three times a day for 8 to 12 months and compared the results with those in 9 untreated subjects (4 normal subjects and 5 with adenoma). All 20 subjects had aberrant crypt foci at base line. RESULTS: We identified 3155 aberrant crypt foci, 161 of which were dysplastic; the prevalence and number increased with age. There were significant (P<0.001) correlations between the number of aberrant crypt foci, the presence of dysplastic foci, the size of the foci, and the number of adenomas. After sulindac therapy, the number of foci decreased, disappearing in 7 of 11 subjects. In the untreated control group, the number of foci was unchanged in eight subjects and slightly increased in one (P<0.001 for the difference between the groups). CONCLUSIONS: Aberrant crypt foci, particularly those that are large and have dysplastic features, may be precursors of adenoma and cancer.

Adenoma↗
PubMed1998

Differentiation induction by a tumor-necrosis-factor mutant 471 in human myelogenous leukemic cells via tumor-necrosis-factor receptor-p55.

The present study examined differentiation-inducing activity by various tumor-necrosis-factor(TNF) mutants against the human leukemic cell lines HL-60 and U-937. Mutant TNF 471, from which 7 N-terminal amino acids of native TNF were deleted and Pro8, Ser9 and Asp10 were replaced by Arg, Lys and Arg, possessed the highest activity among the TNF mutants, and its activity was 120-fold that of native TNF. The various biological activities of TNF were signaled through 2 distinct receptors, p55 and p75. Although cytotoxicity was reported to involve mainly p55, this differentiation-inducing activity was not well understood. The fact that the affinity of TNF 471 was higher to p55 and lower to p75 than that of native TNF by a binding competition assay suggested that the differentiation-inducing activity was also signaled through p55. To verify this hypothesis, the human myelogenous leukemic cell line, KG-1, which scarcely expresses either receptor and does not differentiate with TNF, was transduced with the p55 or p75 gene. Subsequently p55 transfectants manifested a greater ability to differentiate; however, p75 transfectants did not differ from parental cells or from mock-transfectants. Further, the differentiation of p55 transfectants induced by TNF was reduced by the inhibitor of protein-kinase-C (PKC), staurosporine. These results indicate that the differentiation-inducing activity was signaled through the TNF receptor, p55, via PKC and that the excellent ability of TNF 471 to induce differentiation was related to its high affinity for p55.

Antigens, CD↗
PubMed1998

Concentrations of thrombopoietin in bone marrow in normal subjects and in patients with idiopathic thrombocytopenic purpura, aplastic anemia, and essential thrombocythemia correlate with its mRNA expression of bone marrow stromal cells.

The function of bone marrow (BM) stromal thrombopoietin (TPO) in megakaryopoiesis remains unknown. In the present study we attempted to clarify the pathophysiological implications of stromal TPO in normal subjects (NS) and in patients with idiopathic thrombocytopenic purpura (ITP), aplastic anemia (AA), and essential thrombocythemia (ET) by measuring TPO concentrations in BM and peripheral blood (PB) and by estimating the levels of stromal TPO mRNA with TaqMan fluorescence-based post-reverse transcription-polymerase chain reaction product detection system. The results showed that TPO concentrations in PB were significantly elevated in patients with ITP (34.9 +/- 11.7 pg/mL) and AA (364.1 +/- 153.5 pg/mL) but within normal range in patients with ET (each 20.0 and 22.1; NS, 22.1 +/- 8.2 pg/mL). In all subjects, the TPO concentrations in BM correlated well with the PB levels, and the former were consistently higher than the latter. The concentrations of TPO in BM also correlated with the levels of TPO mRNA in stromal cells. Furthermore, expression levels of TPO mRNA clearly correlated with megakaryocyte counts in NS and patients with ITP, indicating that stromal TPO actually enhances megakaryopoiesis. Thus, our results in the present study indicate that TPO from BM stromal cells is considered to play an essential role for megakaryopoiesis under various patho-physiological conditions.

Anemia, Aplastic↗
PubMed1998

Tumor efficacy and bone marrow-sparing properties of TER286, a cytotoxin activated by glutathione S-transferase.

TER286 is a latent drug activated by human glutathione S-transferase (GST) isoforms P1-1 and A1-1 to produce a nitrogen mustard alkylating agent. M7609 human colon carcinoma, selected for resistance to doxorubicin, and MCF-7 human breast carcinoma, selected for resistance to cyclophosphamide, both showed increased sensitivity to TER286 over their parental lines in parallel with increased expression of GST P1-1. In primary human tumor clonogenic assays, the spectrum of cytotoxic activity observed for TER286 was both broad and unusual when compared to a variety of current drugs. In murine xenografts of M7609 engineered to have high, medium, or low GST P1-1, responses to TER286 were positively correlated with the level of P1-1. Cytotoxicity was also observed in several other cell culture and xenograft models. In xenografts of the MX-1 human breast carcinoma, tumor growth inhibition or regression was observed in nearly all of the animals treated with an aggressive regimen of five daily doses. This schedule resulted in a 24-h posttreatment decline in bone marrow progenitors to 60% of control and was no worse than for a single dose of TER286. These studies have motivated election of TER286 as a clinical candidate.

Animals↗
PubMed1998

Suppression of intracellular resistance factors by adriamycin augments heat-induced apoptosis via interleukin-1beta-converting enzyme activation in pancreatic carcinoma cells.

Combination of heat and various anticancer drugs can exert a synergistic antitumor effect in vitro and in vivo, though the mechanism is not clear. We have previously shown that endogenous tumor necrosis factor (enTNF) acts as an intracellular resistance factor to inhibit the cytotoxic effect of heat by scavenging oxygen-free radicals via the induction of manganous superoxide dismutase (MnSOD). Consequently, we examined whether the suppression of these resistance factors by combining anticancer drugs and heat causes an augmentation of heat-induced cytotoxicity. The human pancreatic carcinoma cell line, PANC-1, constitutively expresses appreciable amounts of enTNF and also demonstrates heat resistance. After treatment of these cells for 15 hr with adriamycin (ADM), the expression of enTNF was decreased by 43%, and MnSOD activity was suppressed by 55%. The cytotoxic effects of the treatment of PANC-1 cells with ADM followed by heat were greater than the sum of those observed with the agents administrated individually. Heat-induced apoptosis was also augmented by pretreatment with ADM. Furthermore, the interleukin-1beta-converting enzyme inhibitor, Ac-YVAD-CMK, reversed the augmented cytotoxicity. Our results indicate that suppression of intracellular resistance factors such as enTNF and MnSOD plays an important role in apoptosis seen after heat and ADM combined therapy.

Apoptosis↗
PubMed1998

Orthotopic growth and metastasis of human non-small cell lung carcinoma cell injected into the pleural cavity of nude mice.

We have constructed a metastatic model of human non-small cell lung cancer (NSCLC) by injection of NSCLC cell lines directly into the left pleural cavity of BALB/c nude mice. All of seven NSCLC cell lines, which are tumorigenic after subcutaneous injection, were successfully transplanted in the pleural cavity, while only three of the seven cell lines produced lung metastatic colonies after intravenous injection. Tumors grew extensively in the pleural cavity and infiltrated into the lung parenchyma directly. Furthermore, tumors metastasized to the mediastinum and contralateral pleural cavity through lymphatic routes. Since this model is easy to perform and the result is reproducible, it would be useful for studies on the biological behavior and treatment of human NSCLC in vivo.

Animals↗
PubMed1998

A proof of glutathione S-transferase-pi-related multidrug resistance by transfer of antisense gene to cancer cells and sense gene to bone marrow stem cell.

In order to directly prove the involvement of GST-pi in drug resistance, it's antisense gene was transduced into human colorectal cancer cell line which has been shown to express high level of GST-pi and the sensitivity of this cell line to anticancer drugs were assessed. The transfectant showed higher sensitivity to adriamycin (3.3-fold), Cisplatnum (2.3-fold), Melphalan (2.2-fold), Etoposode (2.2-fold) than the parental cell, while the sensitivity to vincristine, mitomicin C, 5-fluorouracil was unchanged by transfection. When the transfectant and parental cells were innoculated in nude mice and treated with adriamycin, a significant suppression of tumor growth was observed with the transfectant as compared to the parental cell. On the basis of this observation, we then transduced sense GST-pi gene into human bone marrow stem cells (CD34+ cells) to protect them from toxicity of anticancer drug. The gene transduced CD34+ cells formed more CFU-GM than nontransduced CD34+ cell in the presence of adriamycin (30 ng/ml). Thus, the autotransplantation of GST-pi gene transduced cell into cancer patients to protect the bone marrow from subsequent highdose chemotherapy is considered to be a new strategy for cancer gene therapy.

Animals↗