Biomedical subjects

N Oku

Publications and source records attributed to N Oku.

At least 109 records · Page 6Linked to original sources

PubMed1994

Therapeutic effect of reticuloendothelial system (RES)-avoiding liposomes containing a phospholipid analogue of 5-fluorouracil, dipalmitoylphosphatidylfluorouridine, in Meth A sarcoma-bearing mice.

Reticuloendothelial system (RES)-avoiding liposomes are known to accumulate in tumor tissues due to passive targeting. Dipalmitoylphosphatidylfluorouridine (DPPF), a potent antitumor agent readily incorporated into the lipid bilayer, was embedded in RES-avoiding liposomes modified with a uronic acid derivative, palmityl-D-glucuronide (PGlcUA). The therapeutic effect of DPPF in PGlcUA-liposomes was examined in tumor-bearing mice. Free or liposomal DPPF was injected intravenously into BALB/c mice bearing subcutaneously implanted Meth A sarcomas. The RES-avoiding liposomal formulation using PGlcUA was effective in reducing tumors, and prolonging survival time compared with free DPPF and also DPPF in conventional liposomes. Therefore, PGlcUA-liposomes might be of practical use as drug carriers for anticancer agents, especially their derivatives for embedding in liposomal membranes.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1994

Tyrosine phosphorylation of beta-catenin and plakoglobin enhanced by hepatocyte growth factor and epidermal growth factor in human carcinoma cells.

The effect of hepatocyte growth factor/scatter factor (HGF/SF) and epidermal growth factor (EGF) on cadherin-mediated adhesion of human carcinoma cells was studied. HGF/SF induced scattering of colonic adenocarcinoma HT29 and gastric adenocarcinomas MKN7 and MKN74 cells. Likewise, EGF induced scattering of HT29 and MKN7 cells. These cells expressed E-cadherin, which was concentrated at cell-cell contact sites. When the scattering of these cells was induced by HGF/SF or EGF, the E-cadherin concentration at cell-cell boundaries tended to decrease. Immunoblotting analyses, however, demonstrated that these growth factor treatments did not alter the expression of E-cadherin and E-cadherin-associated proteins, alpha- and beta-catenin and plakoglobin. beta-Catenin, plakoglobin and an unidentified 115-kDa molecule associated with E-cadherin were found to be phosphorylated at tyrosine residues, and these phosphorylations were enhanced by the growth factor treatments. These results suggest that HGF/SF and EGF may modulate the function of the cadherin-catenin system via tyrosine phosphorylation of cadherin-associated proteins.

Cadherins↗

PubMed1994

Effect of granulocyte colony-stimulating factor on hematopoietic recovery after peripheral blood progenitor cell transplantation.

To examine the effect of granulocyte colony-stimulating factor (G-CSF) on hematopoietic recovery after high-dose chemotherapy and peripheral blood progenitor cell transplantation (PBPCT), 20 patients with hematologic malignancies were divided into two groups. One group was given G-CSF at a daily dose of 50 micrograms/m2 subcutaneously, the other received no G-CSF. Neutrophil recovery was accelerated in the G-CSF treated patients and exceeded 0.5 x 10(9)/l at a median of 10 days post-PBPCT compared with 14 days in the control group (p < 0.01). This reduction led to a decrease in antibiotic use and a trend toward fewer febrile days in the G-CSF treated group.

Adolescent↗

PubMed1994

Phenotypic differences of CD34-positive stem cells harvested from peripheral blood and bone marrow obtained before and after peripheral blood stem cell collection.

Using two-color flow cytometry, we analyzed the subpopulations of CD34+ stem and progenitor cells in the blood and bone marrow from 10 patients with hematological malignancies. Peripheral blood mononuclear cells (PBMNC) harvested after chemotherapy (high-dose Ara C and VP-16) and rhG-CSF, and BM mononuclear cells, which were obtained before chemotherapy (BMMNCbefore) and after the stem cell collection (BMMNCafter) were isolated by Ficoll-Hypaque centrifugation. The purified cells were stained with FITC-conjugated anti-CD34 antibody and one of the following PE-conjugated antibodies: anti-CD7, CD10, CD11b, CD11c, CD13, CD19, CD33, CD38, CD45RO, CD56, and HLA-DR. CD34+ PBMNC harvested and the CD34+ BMMNCafter expressed CD13 and CD33 more frequently than CD34+ BMMNCbefore but expressed CD10 and CD19 less frequently than CD34+ BMMNCbefore. These data suggested that harvested PBMNC contain more myeloid lineage committed progenitors than BMMNCbefore, which might contribute to the rapid recovery of neutrophils after peripheral blood stem cell transplantation. No significant phenotypic differences of CD34+ cells between harvested PBMNC and BMMNCafter were observed except for the expression of CD11c. CD34+ PBMNC harvested coexpressed CD11c more frequently than both CD34+ BMMNCbefore and CD34+ BMMNCafter, which expression might be associated with commitment to the monocyte lineage.

Adolescent↗

PubMed1994

Long-circulating liposomes.

Liposomes have been investigated for use as drug carriers, and many previous studies have demonstrated enhanced efficacy of encapsulated drugs and the reduction of the side effects of drugs so entrapped. In many cases liposomal drugs are administered via the bloodstream. The stability in the bloodstream, clearance, and biodistribution are dependent on the composition, size, and charge of the liposomes. Rigid, small-size (100-200 nm) liposomes tend to be retained in the blood without degradation. Since the conventional liposomes are trapped in the reticuloendothelial system (RES), RES targeting by means of liposomes is easily achieved. This tendency of liposomes, however, is the most serious limitation when their target is not the RES. Many attempts have been made to avoid the RES-trapping and to prolong the circulation time of liposomes with monosialoganglioside GM1, polyethyleneglycol, glucuronide derivatives, and so on. When the targets are tumor tissues, these RES-avoiding, long-circulating liposomes passively accumulate in such tissues due to extravasation through the leaky vasculature in the tumor tissues. Therefore, long-circulating liposomes are useful tools, especially for tumor imaging and therapy. In this review, we show examples and discuss the mechanism of RES avoidance by these modifiers of liposomes, with special focus on the glucuronide as a modifier.

Animals↗

PubMed1994

Reconstitution of lymphocyte subsets after peripheral blood stem cell transplantation: two-color flow cytometric analysis.

The reconstitution of lymphocyte subsets after high-dose chemotherapy followed by peripheral blood stem cell transplantation (PBSCT) was studied using two-color flow cytometry in 14 patients with acute leukemia (four AML and two ALL) and malignant lymphoma (six NHL and two HD). The CD3+HLA-DR+ lymphocytes (activated T cells) and CD8+ lymphocytes increased markedly by 4 weeks after PBSCT. Most of the increased CD8+ lymphocytes were CD11b-, S6F1+ cells and CD8+CD11b+ cells remained low throughout the follow-up period. The CD4+ lymphocytes remained below the normal range up to 34 weeks after PBSCT. The ratio of CD4+ to CD8+ lymphocytes (CD4/CD8 ratio) transiently increased and then decreased below 1.0 at 2 weeks after PBSCT. The CD19+ lymphocytes and the CD3-CD16+CD56+ lymphocytes returned to normal levels in the early period. The CD4+CD45RA+ lymphocytes (suppressor-inducer) decreased to below the normal range, while the CD4+CD45RO+ lymphocytes (helper-inducer) increased more rapidly than the CD4+CD45RA+ lymphocytes. This study shows that an immunosuppressed state exists after PBSCT as is seen after bone marrow transplantation (BMT) and that B cell reconstitution is more rapid in PBSCT than in BMT.

Acute Disease↗

PubMed1994

Split dose iodine-123-IMP SPECT: sequential quantitative regional cerebral blood flow change with pharmacological intervention.

UNLABELLED: At least two quantitative rCBF measurements are needed to evaluate rCBF changes with pharmacological intervention. We have developed the split dose 123I-IMP SPECT method, which enables measurement of rCBF to be repeated in a short time. METHODS: Thirty-one cerebrovascular disease patients were investigated to assess reproducibility and vasoreactivity to acetazolamide. During 44-min dynamic SPECT imaging, 123I-IMP injection and respective arterial sampling were performed twice at an interval of about 25 min. The rCBF values were calculated using a microsphere model in which the washout of 123I-IMP from the brain can be negligible in the first several minutes after injection. For the second rCBF measurement, the remaining activity due to the first 123I-IMP injection was estimated and subtracted from the total brain activity. RESULTS: In ten patients, two consecutive resting mean rCBF values in the MCA territory (CBF1 and CBF2) had good correlation (CBF1 = 47.4 +/- 4.0 (ml/min/100 ml: mean +/- s.d.), CBF2 = 45.2 +/- 8.2, CBF2 = 0.900*CBF1 + 2.9, r = 0.915). In 11 patients with occlusive lesions in the unilateral ICA system, mean rCBF in the MCA territory was increased by only 27.7% +/- 14.0% in the affected side by a 1-g intravenous acetazolamide injection, while 44.5% +/- 12.3% increase was found in the nonaffected side. In 10 patients without a major arterial lesion, a 49.7% +/- 17.0% increase of rCBF was demonstrated. CONCLUSIONS: This split dose method 123I-IMP SPECT can be useful to estimate vascular reserve.

Acetazolamide↗

PubMed1994

[Neoplastic angioendotheliosis presenting Tolosa-Hunt syndrome, intraspinal invasion and intraorbital tumor].

A 76-year-old woman with painful erythema on legs and right oculomotor disturbance was diagnosed as neoplastic angioendotheliosis (NAE, B cell type) by skin biopsy. Remission was obtained by 2 courses of VEPA regimen. But 3 months later, she relapsed with right oculomotor, optic, trochlear and trigeminal nerve disturbance which suggested that she had Tolosa-Hunt syndrome. Cerebrospinal fluid (CSF) revealed infiltration of lymphoma cells. She developed intraorbital tumor and died of respiratory failure due to tumor emboli. Autopsy revealed infiltration of tumor cells in the small vessels of systemic organs. This rare case presented intracerebrospinal and intraorbital tumor growth in addition to intravascular infiltration of tumor cells.

Aged↗

PubMed1994

[Aggressive myeloma with subcutaneous tumor and pericardial involvement].

A 67-year-old male was admitted to our hospital because of anemia, thrombocytopenia, and renal failure. On admission he showed splenomegaly and elevated serum LDH level. Bone marrow showed hypercellularity with massive infiltration of lymphoblastoid cells. He was diagnosed as having multiple myeloma (BJ-kappa, stage IIIB). He transiently responded to intensive chemotherapy (VAD, MP, IFN alpha) but relapsed with multiple subcutaneous tumors and pericardial effusion. This is a rare case that the myeloma cell invasion to pericardial space was diagnosed before his death. The level of interleukin 6 (IL-6) in pericardial effusion was 16382 pg/ml, and the myeloma cells obtained from the pericardial effusion responded to IL-6, which suggested that high level of IL-6 closely related to the proliferation of myeloma cells in this case.

Aged↗

PubMed1994

Carbon dioxide reactivity by consecutive technetium-99m-HMPAO SPECT in patients with a chronically obstructed major cerebral artery.

UNLABELLED: In the management of major cerebral artery obstruction, cerebral perfusion reserve is key to introducing cerebral revascularization surgery. The purpose of this study was to evaluate the feasibility of assessing cerebral perfusion reserve by consecutive 99mTc-hexamethyl-propyleneamine oxime (99mTc-HMPAO) SPECT with 5% carbon dioxide (CO2) inhalation. METHODS: The CO2 inhalation and consecutive 99mTc-HMPAO SPECT study was performed on 30 chronic ischemic cerebrovascular disease patients with unilateral major cerebral artery obstruction and on 27 patients without. CO2 reactivity was expressed as the percent increase of 99mTc-HMPAO accumulation from the baseline (%Change) and as a constant k' that was the ratio of 99mTc-HMPAO accumulation per 1 mmHg change of end-tidal CO2 tension by exponential curve fitting. RESULTS: The mean %Change and k' in the middle cerebral artery (MCA) territory on the side without an obstructive lesion or in the cerebellum ranged from 10.0% to 11.1% and from 0.98% to 1.13% per mmHg, respectively. In the MCA territory, an obstructive lesion was noted in 5.9% versus 0.54% per mmHg in the contralateral MCA territory (p < 0.01). Eleven of 30 patients with major cerebral artery obstruction revealed significant asymmetry in the k' value between bilateral MCA territories. CONCLUSION: The results showed compromised cerebral perfusion reserve in the obstructed major cerebral artery territory. The present method was proven clinically useful for evaluating cerebral perfusion reserve in patients with unilateral major cerebral artery obstruction.

Adult↗

PubMed1993

Stimulation of prostaglandin production by hepatocyte growth factor in human gastric carcinoma cells.

Hepatocyte growth factor (HGF), a protein with pleiotropic biological activity affecting cell growth and motility, was found to markedly activate prostaglandin production in human gastric carcinoma TMK-1 cells. HPLC analysis revealed that HGF stimulated the production of prostaglandin E2 (PGE2), which is the major prostaglandin produced in these cells. HGF maximally stimulated PGE2 production at a concentration of 10 ng/ml, and it was a more potent stimulator of PGE2 production than epidermal growth factor (EGF), which is known to stimulate prostaglandin production in various cell lines. The simultaneous addition of HGF and EGF caused no further stimulation of the PGE2 production observed in HGF-treated cells. We showed also that HGF increased the arachidonate release from TMK-1 cells, which release was completely suppressed by the addition of phospholipase A2 (PLA2) inhibitors. Further studies in vitro showed that HGF enhanced cellular activities of cytosolic PLA2 and cyclooxygenase 1.5-fold each. These results indicate that HGF stimulates prostaglandin production through increases in both cytosolic PLA2 and cyclooxygenase activities.

Chromatography, High Pressure Liquid↗

PubMed1993

Arachidonic acid-selective cytosolic phospholipase A2 is crucial in the cytotoxic action of tumor necrosis factor.

The role of phospholipase A2 (PLA2) in the cytotoxic action of tumor necrosis factor (TNF) was examined. Recently, we described the characterization of TNF-resistant sublines isolated from TNF-sensitive cell line L929 (Hayakawa, M., Oku, N., Takagi, T., Hori, T., Shibamoto, S., Yamanaka, Y., Takeuchi, K., Tsujimoto, M., and Ito, F. (1991) Cell Struct. Funct. 16, 333-340). The most remarkable features of these TNF-resistant sublines were the defects in TNF-stimulated arachidonate metabolism. In this study, we characterized the PLA2 activities of these sublines and found a significant decrease in the activity in one of the TNF-resistant sublines, C12 cells. The enzymological features, such as Ca2+ requirement and substrate specificity, suggested that the high molecular weight arachidonoyl-selective cytosolic PLA2 (cPLA2) was involved in the TNF action. Northern hybridization analysis demonstrated the reduced expression of high molecular weight cPLA2 in C12 cells. Furthermore, expression of a cloned cPLA2 cDNA in C12 cells increased the sensitivity of cells to the TNF cytotoxicity. These results indicate the crucial role of the high molecular weight cPLA2 in the TNF-induced cytolysis.

Animals↗

PubMed1993

Inversion of chromosome 16 and eosinophilia in refractory anemia with ring sideroblasts: report of a case.

A 72-year-old male who was admitted to our hospital with severe anemia was diagnosed as refractory anemia with ring sideroblasts (RARS), according to the French-American-British (FAB) classification of myelodysplastic syndromes (MDS). The patient showed persistent eosinophilia with no definite signs of either allergy or a parasitic infection. Chromosomal analysis of bone marrow cells revealed inv(16)(p13q22), a known characteristic of M4Eo acute myeloid leukemia (AML) in the FAB classification. This patient didn't exhibit leukemic transformation during his 20-month clinical course, nor was any found at autopsy. Therefore, this is the first case of RARS to speculate that the chromosomal characteristic inv(16)(p13q22) might be specific for eosinophilia rather than AML.

Aged↗

PubMed1993

Tumor imaging with technetium-99m-DTPA encapsulated in RES-avoiding liposomes.

For passive targeting of liposomes to tumor tissues, we earlier developed reticuloendothelial system (RES)-avoiding liposomes modified with a uronic acid derivative, palmityl-D-glucuronide (PGlcUA). In the present study, we encapsulated technetium-99m (99mTc)-diethylenetriaminepentaacetic acid (DTPA) in PGlcUA-liposomes (dipalmitoylphosphatidylcholine:cholesterol:PGlcUA = 40:40:20 as a molar ratio) and studied the biodistribution of the liposomes in tumor-bearing mice. 99mTc-DTPA encapsulated in liposomes effectively accumulated in tumor tissues after intravenous administration. Corresponding to these results, tumor was strongly imaged by a gamma-camera when 99mTc-DTPA-encapsulated PGlcUA-liposomes were used.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1993

Trilineage response in severe aplastic anemia following long-term therapy with recombinant human granulocyte colony-stimulating factor.

We investigated the effects of long-term therapy with recombinant human granulocyte colony-stimulating factor (rhG-CSF) in a 69-year-old man with severe aplastic anemia (SAA). The patient was too old to receive a bone marrow transplantation, and high-dose methylprednisolone and antilymphocyte globulin were ineffective. We administered rhG-CSF in combination with metenolone acetate. Trilineage blood cell components were recovered 6 months later. These findings suggest that long-term G-CSF therapy may be beneficial in patients with SAA who are not candidates for bone marrow transplantation.

Aged↗

PubMed1993

Recombinant human granulocyte colony-stimulating factor in combination with continuous infusion of cytosine arabinoside for the treatment of refractory acute myelogenous leukemia.

Because recombinant human granulocyte colony-stimulating factor (G-CSF) has been reported to increase the sensitivity of acute myelogenous leukemia (AML) blast cells to cytosine arabinoside (Ara-C) in vitro, we treated a patient with refractory AML with an Ara-C-based regimen in combination with G-CSF (G-CSF/Ara-C therapy). G-CSF (50 micrograms/m2/day, subcutaneous injection) was administered simultaneously with a continuous intravenous infusion of Ara-C (70 mg/m2/day). Complete remission was achieved, however, severe neutropenia, documented infection, stomatitis, and diarrhea were observed. In vitro studies using 3H-thymidine uptake and dual parameter flow-cytometric analysis of DNA and proliferating cell nuclear antigen showed that leukemic blast cells in S phase were increased after incubation with G-CSF. G-CSF also enhanced expression of the transferrin receptor (CD71) on blast cells in vitro. These observations suggest that G-CSF/Ara-C therapy may be useful in the treatment of high-risk AML.

Bone Marrow↗

PubMed1993

The synthesis and in vitro and in vivo stability of 5-fluorouracil prodrugs which possess serum albumin binding potency.

For a new drug delivery system of 5-fluorouracil, we prepared prodrugs possessing certain desired properties. The prodrugs, 1-(N-4-chlorophenyl-N-methylcarbamoyl)-5-fluorouracil and 1-(N-2,4-dichlorophenyl-N-methylcarbamoyl)-5-fluorouracil, contain high serum albumin binding potency and a comparably long half life in the bloodstream in vivo to Tegafur. These two prodrugs are expected to be retained in the bloodstream as a polymeric complex with albumin and to circulate in the body for a long time, like a polymeric prodrug.

Animals↗

PubMed1993

[Acute basophilic leukemia: a case report].

A 56-year-old woman was admitted to our hospital in January, 1990 because of fever and petechiae. Leukocyte count of peripheral blood showed 41,000/microliters with 89% immature cells, and bone marrow was normocellular with 96.2% immature cells. They were medium to large in size, positive for peroxidase staining, CD-13 and CD-33. Half of them contained azurophilic granules. They showed metachromasia by toluidine blue, contained basophilic granules in electron microscopic examination and reacted to G-CSF, G-CSF and IL-3. She was diagnosed as acute basophilic leukemia and treated with BHAC-DMP and B triple-V regimen, but remission was not attained. She died of peritonitis due to gastrointestinal tract perforation and pneumonia in March, 1990. This is the fifteenth case of acute basophilic leukemia reported in Japan, and the hematological examinations performed in this patient were demonstrated.

Bone Marrow↗