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Biomedical subjects

M Naito

Publications and source records attributed to M Naito.

At least 199 records · Page 11Linked to original sources
PubMed1998

Detection of circulating tumor cells in a patient with intravascular lymphomatosis: a case study examined by the cytology method.

Detection of circulating tumor cells in a patient with intravascular lymphomatosis (IVL) of the lung is reported. Peripheral blood cells were suspended in an isotonic sodium chloride solution, and red blood cells were lysed. The suspension was smeared on glass slides, fixed in 95% ethanol solution and stained using the Papanicolaou method. At the diagnosis of IVL, approximately 65 tumor cells were detected in one smear preparation, which contained about 8 x 10(5) nucleated cells. However, tumor cells disappeared from peripheral blood when those in the lung were eliminated by multiagent chemotherapy. Cytology examination of peripheral blood cells may be of assistance in the early diagnosis of IVL and in the assessment of therapeutic intervention.

Adult↗
PubMed1998

Proportion of blasts with a clear halo around nucleoli at the end of induction therapy of acute myeloid leukemia correlates with achievement of complete remission, remission duration and relapse.

Bone marrow aspirates from 60 patients with acute myeloid leukemia (AML) were investigated using 95% ethanol fixation Papanicolaou stained preparations. The blasts were grouped into those with a clear halo around nucleoli (BCHN) and those without a clear halo. The patients were classified into three groups according to the degree of persistent BCHN at the end of induction therapy: group 1, no BCHN; group 2, less than 1% BCHN; and group 3, 1% or more BCHN. All patients in groups 1 (17 cases) and 2 (12 cases), and 12 of 31 cases in group 3 achieved complete remission (CR). Of 17 patients in group 1, two underwent bone marrow transplantation and two died from infection. Of the 37 patients who achieved CR, relapse was observed in two of 13 patients in group 1, and in all patients in groups 2 and 3. As to the patients treated with N4-behenoyl-1-beta-D-arabinofuranosyl-cytosine + daunorubicin + 6-mercaptopurine + prednisolone (BHAC-DMP) protocol, the percentages and number of BCHN at the diagnosis of AML in group 1 were significantly lower than those of groups 2 and 3. The percentage and number of BCHN at the diagnosis of AML were significant factors for the achievement of CR and for the prediction of long-term outcome. The reduction of BCHN to less than 1% at the end of induction therapy is a good indicator for the achievement of CR, and the disappearance of BCHN is a useful target for a long-lasting first CR; conversely, the persistence of BCHN is a major adverse factor for relapse.

Acute Disease↗
PubMed1998

Efflux transport of tolbutamide across the blood-brain barrier.

In an attempt to determine the reason for the low brain distribution of tolbutamide, we have demonstrated the transport of tolbutamide from the brain to the blood via a non-P-glycoprotein efflux transport system which is inhibited by sulphonamides. We evaluated the directional transport of tolbutamide across the blood-brain barrier by means of an in-vivo brain-tissue distribution study and experiments on in-vitro transcellular transport and uptake in cultured mouse-brain capillary endothelial cells (MBEC4). The brain-to-unbound-plasma concentration ratio of [14C]tolbutamide increased in the presence of high concentrations of unlabelled tolbutamide or sulphonamide at steady-state in-vivo. The brain-to-blood concentration ratios of [14C]tolbutamide were very low compared with that of [3H]propranolol obtained by in-vivo integration plot analysis. From the in-vitro transcellular transport study using a monolayer of MBEC4 cells, we found that the abluminal-to-luminal flux of [14C]tolbutamide was higher than the reverse flux. Both luminal-to-abluminal and abluminal-to-luminal transport of tolbutamide were saturable. The maximum transport rate (Jmax), the half-saturation concentration (Kt), and the first-order rate constant (kd) were 65.9 +/- 29 pmol min(-1) (mg protein)(-1), 7.54 +/- 4.4 microM, and 4.89 +/- 0.34 microL min(-1) (mg protein)(-1), respectively, for luminal-to-abluminal transport, and 128 +/- 66 pmol min(-1) (mg protein)(-1), 5.59 +/- 4.2 microM, and 4.43 +/- 0.86 microL min(-1) (mg protein)(-1) , respectively, for abluminal-to-luminal transport. At therapeutic plasma concentrations of tolbutamide (1-16.9 microM), the efflux rate would be faster than the influx rate. The estimated net efflux was consistent with the very low in-vivo brain distribution of tolbutamide. The efflux process observed in MBEC4 cells was inhibited by sulphonamides such as sulphaphenazole, sulphamethoxazole and sulpha-dimethoxine whereas the steady-state uptake of [14C]tolbutamide was not affected by either cyclosporin or verapamil, specific inhibitors of P-glycoprotein. These findings suggest that tolbutamide is partly transported from the brain via the non-P-glycoprotein-efflux transport system, which is inhibited by sulphonamides.

Animals↗
PubMed1998

P-glycoprotein-mediated transport of itraconazole across the blood-brain barrier.

The mechanism for the accumulation of itraconazole (ITZ) in its elimination from the brain was studied in rats and mice. The concentration of ITZ in liver tissue declined in parallel with the plasma ITZ concentration until 24 h after intravenous injection of the drug (half-life, 5 h); however, the ITZ in brain tissue rapidly disappeared (half-life, 0.4 h). The time profiles of the brain/plasma ITZ concentration ratio (Kp value) showed a marked overshooting, and the Kp value increased with increasing dose; these phenomena were not observed in the liver tissue. This finding indicates the occurrence of a nonlinear efflux of ITZ from the brain to the blood. Moreover, based on a pharmacokinetic model which hypothesized processes for both nonlinear and linear effluxes of ITZ from the brain to the blood, we found that the efflux rate constant in the saturable process was approximately sevenfold larger than that in the nonsaturable process. The Kp value for the brain tissue was significantly increased in the presence of ketoconazole or verapamil. The brain Kp value for mdr1a knockout mice was also significantly increased compared with that of control mice. Moreover, the uptake of vincristine or vinblastine, both of which are substrates of the P glycoprotein (P-gp), into mouse brain capillary endothelial cells was also significantly increased by ITZ or verapamil. In conclusion, P-gp in the brain capillary endothelial cells participates in a process of active efflux of ITZ from the brain to the blood at the blood-brain barrier, and ITZ can be an inhibitor of various substrates of P-gp.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Hypertrophic cardiomyopathy with type I CD36 deficiency.

CD36 is a multifunctional membrane-type receptor glycoprotein that reacts with oxidized low-density lipoprotein and long-chain fatty acid (LCFA). A patient presented with hereditary hypertrophic cardiomyopathy (HCM) and type I CD36 deficiency (neither platelets nor monocytes expressed CD36) but showed no myocardial LCFA accumulation. CD36 was expressed in the capillary endothelial cells of the cardiac muscle of a control subject, while the patient's myocardial capillary endothelial cells were completely CD36-negative. These results suggest that type I CD36 deficiency is closely related to hereditary HCM and lack of myocardial LCFA accumulation.

CD36 Antigens↗
PubMed1998

Expression of exogenous DNA in the gonads of chimaeric chicken embryos produced by transfer of primordial germ cell transfected in vitro and subsequent fate of the introduced DNA.

The expression and fate of exogenous DNA (lacZ gene), introduced into the gonads of chimaeric embryos and chickens that had been produced by transfer of primordial germ cells (PGCs) transfected in vitro, were examined. PGCs obtained from embryonic blood were transfected in vitro by lipofection and transferred to the partially sterilized recipient embryos. Expression of the lacZ gene was observed in the gonads of chimaeric embryos incubated for 3 days after the PGC injection (71.2%, 37/52). Introduction of the lacZ gene into the gonads of chimaeric embryos was confirmed by PCR analysis. The percentage of embryos with gonads positive for the lacZ gene was 95% (38/40) after 3 days of incubation after the PGC injection. The lacZ gene, however, appeared to persist episomally but was gradually lost during embryonic development. After 17 days of incubation after the PGC injection, the lacZ gene was detected in only 14.3% (3/21) of the embryos examined. Although the lacZ gene was detected in the gonads of two hatched chicks (11.1%), it was not detected in the gonads of chimaeric chickens at sexual maturity. Offspring derived from the lipofected PGCs were obtained from the chimaeric chickens at frequencies of 12.1-69.9% in males and 71.6-97.6% in females. The technique developed in the present work could be used to test the expression of exogenous DNA in the gonads of early chicken embryos and should facilitate the production of transgenic chickens.

Animals↗
PubMed1998

Expression of macrophage colony-stimulating factor, scavenger receptors, and macrophage proliferation in the pregnant mouse uterus.

During pregnancy, mouse uterine epithelial cells produce and secrete a large amount of macrophage colony-stimulating factor (M-CSF/CSF-1). Macrophages accumulate and proliferate in the undecidualized endometrium of the pregnant uterus. Observations showed that macrophages expressed scavenger receptor class A (type I and type II) and class C (macrosialin). Scavenger receptors appeared to be involved in the removal of apoptotic cells in the degenerated decidual tissue. The expression of class A and class C scavenger receptor mRNAs in the uterus of pregnant mice was elevated but the expression of class B scavenger receptor (CD36) mRNA was similar to that of non-pregnant mice. The expression of various cytokines and chemokines, including M-CSF, monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein 1-alpha (MIP1-alpha), was enhanced in the uterus of pregnant mice, suggesting that these molecules regulate macrophage chemotaxis and immunological function in the uterus. These findings imply that the pregnant uterus provides a microenvironment for the recruitment, differentiation, and proliferation of macrophages and the regulation of scavenger receptor and cytokine expression for a successful pregnancy.

Animals↗
PubMed1998

Effects of granulocyte/macrophage colony-stimulating factor on the development and differentiation of CD5-positive macrophages and their potential derivation from a CD5-positive B-cell lineage in mice.

In co-cultures of either the murine pre-B cell line J13, fetal liver cells, or adult peritoneal or bone marrow cells with ST2 mouse bone marrow stromal cells in the presence of granulocyte/macrophage colony-stimulating factor (GM-CSF), the development of CD5+ macrophages was demonstrated by immunohistochemical staining and flow cytometry. Although CD5+ macrophages were not present in the peritoneal cavities of normal mice, approximately 30% of the peritoneal macrophages in viable motheaten (mev/mev) mice, deficient in SHP-1 protein tyrosine phosphatase, expressed cell surface CD5 and B220, markers for B cells. In the mev/mev mice, GM-CSF level in peritoneal fluid was increased significantly. At 5 days after daily intravenous injection with GM-CSF, many CD5+ macrophages appeared in the peritoneal cavity and in omental milky spots of normal mice but fewer in osteopetrosis (op) mutant mice, deficient in macrophage (M)-CSF. These results indicate that GM-CSF, in combination with M-CSF, induces the development and differentiation of CD5+ macrophages in the peritoneal cavity, particularly in the omental milky spots of mice. In the peritoneal cavity of GM-CSF-treated mice, the percentages of hematopoietic progenitor cells doubly positive for CD5 and CD34 or c-kit and of macrophage precursor cells doubly positive for CD5 and ER-MP58 or ER-MP20 were increased significantly during the development of CD5+ macrophages and CD5 B cells, suggesting that CD5+ macrophages and B cells may share a bipotential progenitor in vivo.

Animals↗
PubMed1998

Characterization of efflux transport of organic anions in a mouse brain capillary endothelial cell line.

Cumulative evidence suggests that several organic anions are actively effluxed from the brain to the blood across the blood-brain barrier (BBB). We examined the possibility of the presence of primary active transporters for organic anions (multidrug resistance associated protein (MRP) and canalicular multispecific organic anion transporter (cMOAT)) on the BBB by measuring the ATP-dependent uptake of 2,4-dinitrophenyl-S-glutathione (DNP-SG) and leukotriene C4 (LTC4) into membrane vesicles prepared from a cell line derived from mouse brain capillary endothelial cells (MBEC4). The ATP-dependent uptake of DNP-SG into the membrane vesicles was osmotically sensitive and was also supported by GTP, but not by AMP or ADP. An ATPase inhibitor, vanadate, blocked the ATP-dependent uptake of DNP-SG. The ATP-dependent uptake process was saturable, with Km values of 0.56 and 0.22 microM, and Vmax values of 5.5 and 27.5 pmol/min/mg protein for DNP-SG and LTC4, respectively. Northern and Western blot analyses showed the expression of murine MRP but not cMOAT in MBEC4 cells. Western blot analysis of the rat cerebral endothelial cells indicated the expression of protein(s) that is detectable with MRPr1, an antibody against MRP. These results, together with previous findings that both DNP-SG and LTC4 are good ligands for MRP, suggest that MRP is responsible for the unidirectional, energy-dependent efflux of organic anions from the brain into the circulating blood across the BBB.

Animals↗
PubMed1998

Bone remodeling and macrophage differentiation in osteopetrosis (op) mutant mice defective in the production of macrophage colony-stimulating factor.

Mice homozygous for the osteopetrosis (op) mutation are characterized by defective differentiation of osteoclasts, monocytes, and tissue macrophages due to a lack of functional macrophage colony-stimulating factor (M-CSF/CSF-1) activity. In young (4-6 week-old) op/op mice, the bone marrow cavities were filled with spongious bone. In aged (50-72 week-old) op/op mice, the bone marrow cavities were markedly reconstructed and marrow hematopoiesis was expanded. Numbers of osteoclasts and bone marrow macrophages in aged op/op mice were increased but most of the osteoclasts were mononuclear cells and showed poorly developed ruffled borders. Lysosomes of bone marrow macrophages were laden with abundant crystalloid materials in aged op/op mice and aged littermate mice. However, such macrophages were not observed in young op/op mice nor in young littermates. In contrast to the marked increase in numbers of osteoclasts and macrophages in the bone marrow, the number of Kupffer cells in the liver did not increase in aged op/op mice. Kupffer cells in aged op/op mice did not show ultrastructural maturation with aging and contained a few crystalloid structures. M-CSF administration to aged op/op mice induced numerical increases in Kupffer cells and lysosomes in Kupffer cells, disappearance of crystalloid structures in lysosomes of Kupffer cells, and the development of ruffled border in osteoclasts. These findings indicate that M-CSF-independent mechanisms for macrophage and osteoclast development in aged op/op mice are restricted to bone marrow. M-CSF plays important roles in the differentiation of macrophage and osteoclast and the production and function of lysosomes.

Aging↗
PubMed1998

Two-dimensional electrophoretic analysis of humoral responses to culture filtrate of Mycobacterium bovis BCG in patients with leprosy and tuberculosis.

Sera from 3 lepromatous (LL), 3 borderline lepromatous (BL), 3 mid-borderline (BB), 3 borderline tuberculoid (BT), 2 tuberculoid (TT) and 4 tuberculosis (TB) patients and 3 healthy individuals were examined for their reactivities against the proteins in the culture filtrate of BCG separated by two-dimensional electrophoresis (2-DE). The sera were obtained from patients who were untreated. Sera from LL and BL patients reacted strongly with the antigen 85 (Ag85) complex and MPB51. Sera from LL and BL patients also weakly reacted with the newly identified 29-, 24- and 23-kDa spots. Sera from the other patients reacted similarly, but the levels of reaction were remarkably lower than those form LL and BL patients. Mycobacterium leprae antigens that are analogous to BCG AG85 and MPB51 are suggested as the main targets for the humoral immunity of untreated patients. The reactivities of sera with newly identified antigens may provide the potential for predicting the severity and prognosis of diseases.

Antibodies, Bacterial↗
PubMed1998

Serological analysis of C-terminal region of alpha antigen from Mycobacterium avium-intracellulare complex and Mycobacterium tuberculosis.

The alpha antigen, which is a 30 kDa protein secreted by mycobacterial species, is an immunodominant antigen. The C-terminal regions of alpha antigens are highly divergent, though there are regions where the amino acid sequence of alpha antigen is conserved. We investigated whether the C-terminal regions of the Mycobacterium avium alpha antigen, M. intracellulare alpha antigen and M. tuberculosis alpha antigen contain sequence-specific B-cell epitopes. The C-terminal regions of M. avium alpha antigen and M. intracelluare alpha antigen reacted to anti-M. avium alpha antigen but not to anti-M. tuberculosis alpha antigen derived from rabbits. Thus, M. avium and M. intracellulare have an antigenic determinant in common with rabbit. The C-terminal region of M. tuberculosis alpha antigen did not react to anti-M. avium alpha antigen or anti-M. tuberculosis alpha antigen. An enzyme-linked immunosorbent assay revealed that only the C-terminal region of M. avium alpha antigen reacted to the sera of two of six patients with M. avium-intracellulare (MAC) but not to the sera of patients with M. tuberculosis. In contrast, the C-terminal regions of M. intracellulare alpha antigen and M. tuberculosis alpha antigen were not recognized by the sera from patients with MAC or M. tuberculosis. This region of M. avium alpha antigen can produce a sequence-specific B-cell epitope in humans.

Amino Acid Sequence↗
PubMed1997

Development, differentiation, and maturation of Kupffer cells.

Primitive macrophages first develop in the murine and human yolk sac and then differentiate into fetal macrophages. Primitive or fetal macrophages enter the blood stream and migrate into the fetal liver. Fetal macrophages possess a high proliferative capacity and express antigens and peroxidase activity of resident macrophages with the progress of gestation; they become mature and then transform into Kupffer cells. In contrast, myelopoiesis and monocytopoiesis are not active in yolk sac hematopoiesis and in the early stages of hepatic hematopoiesis. Precursor cells of primitive or fetal macrophages exist and granulocyte/macrophage colony-forming cells develop in the yolk sac and in the early stages of fetal liver development, whereas macrophage colony-forming cells emerge and increase later in fetal liver development. In vitro, similar colonies were formed from each fetal hematopoietic cell in the presence of different macrophage growth factors. During culturing of the yolk sac cells and hepatic hematopoietic cells on a monolayer of mouse stromal cell line, ST2, primitive or fetal macrophage colonies developed before the formation of monocyte colonies, suggesting the existence of a direct pathway of differentiation from primitive macrophages into fetal macrophages during ontogeny. In severely monocytopenic mice induced by the administration of strontium-89, Kupffer cells have a proliferative capacity and are maintained by self-renewal. In macrophage colony-stimulating factor (M-CSF)-deficient (op/op) mice, the number of Kupffer cells is reduced, and they are characterized by immature morphology and a proliferative potential similar to that of primitive or fetal macrophages during ontogeny. Immediately after the administration of M-CSF to op/op mice, Kupffer cells start proliferating and become mature. This finding indicates that M-CSF plays an important role in the differentiation and proliferation of Kupffer cells.

Adult↗
PubMed1997

Requirement of the caspase-3/CPP32 protease cascade for apoptotic death following cytokine deprivation in hematopoietic cells.

Hematopoietic cytokines transduce cell survival signals, which are distinct from the signals necessary for the stimulation of DNA synthesis. Recently, the Ras and phosphatidylinositol 3-kinase pathways have been shown to play important roles in preventing apoptosis in various cell types, e.g. hematopoietic cells and neuronal cells. Withdrawal of cytokine(s), in turn, results in rapid inactivation of these survival pathways and eventually leads to cell death accompanied by the hallmarks of apoptosis. However, the mechanism of cell death caused by cytokine deprivation has not been fully elucidated. In this study, we demonstrate that caspase-3/CPP32, a member of the caspase/interleukin-1beta-converting enzyme family, is activated upon interleukin (IL)-3 deprivation in IL-3-dependent cells as well as IL-2 deprivation in IL-2-dependent cells. In addition, poly(ADP-ribose) polymerase, a cellular substrate for the caspase family proteases, was degraded into apoptotic fragments in both cell lines after cytokine removal. Furthermore, inhibition of a caspase family protease by synthetic peptides suppressed apoptotic death. These results indicate that the activation of a caspase-like protease(s) is required for the progression of apoptosis following cytokine deprivation. However, readdition of IL-3 did not restore the proliferative potential of the cells that survived in the presence of the peptide inhibitor after IL-3 depletion. Therefore, cellular commitment to apoptosis appears to precede the activation of a caspase-like protease(s).

Animals↗
PubMed1997

c-Myc plays a role in cellular susceptibility to death receptor-mediated and chemotherapy-induced apoptosis in human monocytic leukemia U937 cells.

Human monocytic leukemia U937 cells readily undergo apoptosis when they are treated with TNF-alpha, anti-Fas antibody and anticancer drugs such as etoposide and Ara-C. To study the mechanism of apoptosis, we developed a novel apoptosis-resistant variant, UC, from U937 cells. The UC cells showed resistance to apoptosis induced by TNF-alpha, anti-Fas antibody, etoposide and Ara-C. Somatic cell hybridization between U937 and UC showed that apoptosis-resistance to TNF-alpha in UC was genetically recessive and resistance to etoposide was dominant, suggesting that UC has at least two different mutations functionally involved in apoptosis. Mechanistic analysis revealed that UC cells expressed reduced amounts of c-Myc. Transfection of the c-myc gene into UC cells restored the sensitivity of the cells to undergo apoptosis induced by TNF-alpha and anti-Fas, which attributes apoptosis-resistance in this circumstance to the reduced expression of c-Myc. On the other hand, c-myc transfection into UC cells could not restore their sensitivity to etoposide- and Ara-C-induced apoptosis, arguing against the role of c-myc in chemotherapy-induced apoptosis. However, treating the parental U937 cells with antisense oligonucleotides designed to reduce c-Myc expression rendered the cells resistant to etoposide-induced as well as to TNF-alpha-induced apoptosis. These results indicate that the reduced expression of c-Myc in UC is strongly associated with the resistance to etoposide-induced apoptosis. Our finding that c-myc transfection into UC could not restore the sensitivity to etoposide-induced apoptosis, suggests UC could have a second mutation that confers resistance to etoposide-induced apoptosis in a genetically dominant manner. Taken together, our present results indicate that c-Myc plays a role in cellular susceptibility to death receptor-mediated and chemotherapy-induced apoptosis.

Antibodies↗
PubMed1997

Overcoming of multidrug resistance by VA-033, a novel derivative of apovincaminic acid ester.

We have studied the effects of a novel derivative of apovincaminic acid ester, VA-033, on the resistance of tumors to chemotherapeutic agents. VA-033 increased the sensitivity of drug-resistant cell lines (P388/VCR, P388/ADM, AD10, and K562/ADM) to adriamycin or vincristine. The potency of VA-033 was stronger than verapamil. The drug lengthened the survival time of the P388/VCR-implanted mice treated with vincristine. VA-033 increased the intracellular accumulation of vincristine in the tumor cells, and the photolabeling of P-glycoprotein by [3H]azidopine was inhibited by VA-033. VA-033 showed a slight inhibitory effect on the L-type Ca2+ current in the ventricular myocytes, and had less effect on the cardiovascular parameters such as blood pressure, contractile force and atrio-ventricular conduction time than verapamil when administered systemically in the dog. These results suggest that VA-033 may become a beneficial compound as a modifier to the neoplastic cell resistant to multidrugs.

Animals↗
PubMed1997

Apoxin I, a novel apoptosis-inducing factor with L-amino acid oxidase activity purified from Western diamondback rattlesnake venom.

Venom of the western diamondback rattlesnake (Crotalus atrox) induces apoptosis in human umbilical vein endothelial cells, which could result in hemorrhage in tissues bitten by the snake. To identify the hemorrhagic factor, we purified a novel protein, apoxin I, from rattlesnake venom. Apoxin I induced apoptosis in human umbilical vein endothelial, human promyelocytic leukemia HL-60, human ovarian carcinoma A2780, and mouse endothelial KN-3 cells. Amino acid sequence analysis of the apoxin I showed close similarity to L-amino acid oxidase from the Malayan pit viper (Calloselasma rhodostoma). The purified apoxin I oxidized L-leucine but not D-leucine to produce H2O2. The apoxin I-induced apoptosis was inhibited by catalase, a H2O2 scavenger. These results indicate that the H2O2 produced by L-amino acid oxidation by apoxin I is involved in the apoxin I-induced apoptosis and in hemorrhage caused by rattlesnake venom.

Amino Acid Oxidoreductases↗