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Biomedical subjects

H Tsumura

Publications and source records attributed to H Tsumura.

At least 37 records · Page 2Linked to original sources
PubMed2000

Roles of ICAM-1 for abnormal leukocyte recruitment in the microcirculation of bleomycin-induced fibrotic lung injury.

To assess the importance of endothelial intercellular adhesion molecule-1 (ICAM-1) in microvascular leukocyte kinetics in diseased lungs, we investigated the transitional changes in ICAM-1 expression, vascular diameter, and leukocyte behavior in rat pulmonary microcirculation during the development of acute lung injury (ALI) and chronic fibrosis (FIB) evoked by bleomycin (BLM). Observations were made in the isolated perfused lung with a real-time confocal laser luminescence microscope. Microvascular cell kinetics were evaluated by measuring the behavior of fluorescence- labeled leukocytes and erythrocytes in the presence or absence of anti-ICAM-1 monoclonal antibody (1A29). Arteriolar ICAM-1 showed little change at any time after BLM treatment. Venular ICAM-1 was first enhanced at the initial phase of ALI followed by the second upregulation at the early phase of FIB. Capillary ICAM-1 showed a sustained increase at both ALI and FIB. Arteriolar and venular diameters were not altered but capillary diameter decreased during ALI and early FIB stages. Although firm adherence of leukocytes to arteriolar and venular walls was not observed, rolling leukocytes were increased in venules both at the initial phase of ALI and at the early phase of FIB. The leukocyte rolling in venules correlated well with transitional changes in ICAM-1 and was inhibited by 1A29. Sustained entrapment of leukocytes in capillaries was attributed to changes in vascular diameter as well as augmented ICAM-1. In conclusion, ICAM-1 plays an important role in microvascular leukocyte recruitment in both ALI and FIB in the BLM-injured lung.

Animals↗
PubMed2000

Generation of recombinant human large latent transforming growth factor-beta 1 and monoclonal antibodies to it.

Transforming growth factor beta 1 (TGF-beta 1) is a regulator of cell growth and differentiation. It is produced in various of cells and tissues as a biologically latent complex, whose significance is still unknown. We established a Chinese hamster ovary cells that produced recombinant human large latent TGF-beta 1. The growth factor was purified from serum-free conditioned medium of the cell line was purified to apparent homogeneity by four steps of column chromatography. The purified protein gave a single band with the apparent molecular weight of 210,000 on SDS-PAGE, and had four subunits, of 12.5, 40, 53, and 150-190 kDa. These components were identical to TGF-beta 1, the N-terminal remnant of pro-TGF-beta 1, pro-TGF-beta 1, and latent TGF-beta 1 binding protein, respectively. The purified growth factor had biological activity similar to that of the growth factor purified from human platelets. We prepared four monoclonal antibodies by immunization of mice with the recombinant protein. In western blotting, two of the antibodies bound to latent TGF-beta 1 binding protein. The two other antibodies reacted with the N-terminal remnant of pro-TGF-beta 1. Recombinant large latent TGF-beta 1 and its monoclonal antibodies could be used for detailed structural and functional studies of the large latent TGF-beta 1 complex.

Amino Acid Sequence↗
PubMed2000

Cell cycle-independent down-regulation of BCL-2 protein expression in differentiating HL-60 cells.

To understand the relationship between bcl-2 protein expression and the cell cycle during the processes of differentiation, we examined bcl-2 protein levels expressed during cell cycle phases in differentiating HL-60 human leukemia cells by using a two-color flow cytometric method. In exponentially proliferating HL-60 cells bcl-2 protein was constitutively expressed throughout the cell cycle phases, but a small population of G0/G1 cells expressed decreased levels of protein as compared with other cell cycle phases. HL-60 cells can be induced to differentiate to granulocytic pathway by retinoic acid or dimethylsulfoxide, and to monocytic/macrophagic pathway by 1, 25 dihydroxyvitamin D3 or 12-O-tetradecanoylphorbol -13-acetate. During treatment with any of these inducing agents, bcl-2 protein expression was time-dependently down-regulated after 24 h. A two-color flow cytometric analysis revealed that this down-regulation occurred throughout cell cycle phases, indicating that bcl-2 protein expression was down-regulated in cell cycle-independent manner during induction of differentiation in HL-60 cells. To our knowledge, this is the first demonstration suggesting that the regulation of bcl-2 protein expression is not related to the cell cycle during induction of differentiation in HL-60 cells.

Cell Cycle↗
PubMed2000

MR appearance of paraganglioma of the cauda equina. Case reports.

PURPOSE: To investigate the value of MR imaging for preoperative diagnosis of paraganglioma of the cauda equina. MATERIAL AND METHODS: A retrospective review of 2 cases of paraganglioma of the cauda equina examined with MR imaging was undertaken. Features assessed included the homogeneity of the lesions, presence or absence of serpiginous flow void and thin hypointense margins. RESULTS: In case 1, the tumor was hyperintense on the postcontrast examination and serpiginous flow void suggested vessels in the upper pole of the tumor. In case 2, the tumor was encapsulated by a thin hypointense margin on both T1- and T2-weighted images, which suggested hemosiderin. CONCLUSION: The MR appearance may be of great value in the preoperative diagnosis of paraganglioma of the cauda equina.

Cauda Equina↗
PubMed1999

Evaluation by microdensitometry and dual energy X-ray absorptiometry of changes in bone metabolism after gastrectomy.

We used microdensitometry (MD) and dual energy X-ray absorptiometry (DXA) to evaluate impaired bone metabolism in 79 patients who had undergone gastrectomy. With MD, radiographs are simultaneously taken of the second metacarpal bone and an aluminum step-wedge, and the images were analyzed by computer. DXA was used to measure the bone mineral density of the second through fourth vertebrae and the estimated volumetric bone mineral density (EstVBMD) was assessed. Significant positive correlations were obtained between EstVBMD as determined by DXA and metacarpal index (MCI) (r = 0.413, P < 0.01), peak of the cortex (GSmax) (r = 0.362, P < 0.05), peak of the middle portion of the bone marrow (GSmin) (r = 0.412, P < 0.01), and metacarpal bone mineral density (mBMD) (r = 0.413, P < 0.01) as determined by MD. When EstVBMD was compared with MCI, GSmax, GSmin, and mBMD according to sex, age, type of operation, and interval after operation, generally similar trends were obtained. We conclude that the determination by MD of various indices of bone metabolism is useful in the diagnosis of osteopathy after gastrectomy.

Absorptiometry, Photon↗
PubMed1999

Changes in volumetric bone mineral density after gastrectomy as assessed by dual energy X-ray absorptiometry.

We used dual energy X-ray absorptiometry (DXA) to study changes in estimated volumetric bone mineral density (EstVBMD) of the lumbar spine after gastrectomy. The study group comprised 41 men and 32 women. When EstVBMD was compared according to sex among patients younger than 60 years of age, patients 60 to 69 years of age, and patients these three groups in men (0.185 g/cm3, 0.187 g/cm3, 0.187 g/cm3, respectively). In contrast, EstVBMD was significantly lower in women 60 to 69 years of age (0.157 g/cm3) and those 70 years of age or older (0.159 g/cm3) than in women younger than 60 years (0.200 g/cm3) (P < 0.01). When the relation between EstVBMD and the number of months after gastrectomy was studied according to sex in patients younger than 70 years, EstVBMD negatively correlated with the interval after operation in men (r = -0.365, P < 0.05), whereas there was no correlation between these variables in women. These results suggest that after gastrectomy bone mineral density decreases gradually in men younger than 70 years, but not in women. The lack of a consistent change in bone mineral density after gastrectomy in women is apparently caused by the marked effect on bone metabolism of decreased female hormone levels after menopause.

Absorptiometry, Photon↗
PubMed1999

Extraosseous calcified plasmacytoma causing thoracic myelopathy.

We report on a rare, calcified, plasma cell tumor of the spine causing progressive myelopathy. Other unusual features were the lack of an osseous lesion at the site of the mass, considerable calcified amyloid within the mass but no identifiable amyloid elsewhere, and normal serum immunoelectrophoresis.

Amyloid↗
PubMed1999

Asn-linked sugar chain structures of recombinant human thrombopoietin produced in Chinese hamster ovary cells.

Human thrombopoietin (TPO) that regulates the numbers of megakaryocytes and platelets is a heavily N- and O-glycosylated glycoprotein hormone with partial homology to human erythropoietin (EPO). We prepared recombinant human TPO produced in Chinese hamster ovary (CHO) cells and analyzed the sugar chain structures quantitatively using 2-aminobenzamide labeling, sequential glycosidase digestion and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS). We found bi-, tri- and tetraantennary complex-type sugar chains with one or two N-acetyllactosamine repeats, which are common to recombinant human EPO produced in CHO cells. On the other hand, there were triantennary sugar chains with one or two N-acetyllactosamine repeats that were specific to the recombinant human TPO, and their distributions of branch structures were also different. These results suggested that proximal protein structure should determine the branch structure of Asn-linked sugar chains in addition to the glycosyltransferases subset.

Animals↗
PubMed1999

Isolation and characterization of monoclonal antibodies directed against murine FRP-1/CD98/4F2 heavy chain: murine FRP-1 is an alloantigen and amino acid change at 129 (P<-->R) is related to the alloantigenicity.

Nineteen mAb directed against murine fusion regulatory protein-1 (mFRP-1)/4F2/CD98 were isolated and their biological properties were analysed. Intriguingly, mFRP-1 was found to be an alloantigen, namely, FRP-1.1 (DBA/2 and CBA mice type) and FRP-1.2 (BALB/c, C57BL/6 and C3H/He mice type). The nucleotide sequences of FRP-1.1 and FRP-1.2 were determined, demonstrating that amino acid change at 129 (P<-->R) is related to the alloantigenicity. mFRP-1 is expressed on thymocytes, on spleen cells, on peripheral lymphocytes and on blood monocytes, suggesting that the physiological role in vivo of murine FRP-1 is different from that of human FRP-1. The biological activities of antimFRP-1 mAbs showed by the present study are: (i) enhancement of Newcastle disease virus-induced cell fusion; (ii) suppression of HIVgp160-mediated cell fusion; and (iii) induction of aggregation and multinucleated giant cells of monocytes/macrophages.

Amino Acid Sequence↗
PubMed1999

Nitric oxide differentially attenuates microvessel response to hypoxia and hypercapnia in injured lungs.

The issue of whether the acinar microvessel response to alveolar hypoxia and hypercapnia is impaired in injured lungs has not been vigorously addressed, despite the importance of knowing whether it is or not when treating patients with serious lung injury in terms of permissive hypercapnia. Applying a real-time laser confocal luminescence microscope, we studied hypoxia- and hypercapnia-induced changes in the diameter of the intra-acinar arterioles, venules, and capillaries of isolated rat lungs harvested from animals exposed for 48 h to 21% O(2) (group N) or 90% O(2) (group H). Measurements were made with and without inhibition of nitric oxide (NO) synthase (NOS) by N(omega)-nitro-L-arginine methyl ester or of cyclooxygenase (COX) by indomethacin at different basal vascular tones evoked by thromboxane A(2) (TXA(2)) analog. Hypoxia in the absence of TXA(2) contracted arterioles in group N but not in group H. Attenuated hypoxia-induced arteriole constriction was restored almost fully by inhibiting NOS and partially by inhibiting COX. Hypercapnia induced venule dilation in group N, but did not dilate venules in group H, irrespective of TXA(2). NOS inhibition in hypercapnia unexpectedly enhanced venule and arteriole dilation in group H. These responses no longer occurred when NOS and COX were inhibited simultaneously. In conclusion, microvessel reactions to hypoxia and hypercapnia are abnormal in hyperoxia-injured acini, in which NO directly attenuates hypoxia-induced arteriole constriction, whereas COX inhibited by excessive NO impedes hypercapnia-induced microvessel dilation.

Animals↗
PubMed1998

Response of intra-acinar pulmonary microvessels to hypoxia, hypercapnic acidosis, and isocapnic acidosis.

To elucidate the differential reactivity of pulmonary microvessels in the acini to hypoxia, excessive CO2, and increased H+, we investigated changes in the diameter of precapillary arterioles, postcapillary venules, and capillaries in isolated rat lungs on exposure to normocapnic hypoxia (2% O2), normoxic hypercapnia (15% CO2), and isocapnic acidosis (0.01 mol/L HCl). Microvascular diameters were precisely examined using a real-time confocal laser scanning luminescence microscope coupled to a high-sensitivity camera with an image intensifier. Measurements were made under conditions with and without indomethacin or N(omega)-nitro-L-arginine methyl ester to assess the importance of vasoactive substances produced by cyclooxygenase (COX) or NO synthase (NOS) as it relates to the reactivity of pulmonary microvessels to physiological stimuli. We found that acute hypoxia contracted precapillary arterioles that had diameters of 20 to 30 microm but did not constrict postcapillary venules of similar size. COX- and NOS-related vasoactive substances did not modulate hypoxia-elicited arteriolar constriction. Hypercapnia induced a distinct venular dilatation closely associated with vasodilators produced by COX but not by NOS. Arterioles were appreciably constricted in isocapnic acidosis when NOS, but not COX, was suppressed, whereas venules showed no constrictive response even when both enzymes were inhibited. Capillaries were neither constricted nor dilated under any experimental conditions. These findings suggest that reactivity to hypoxia, CO2, and H+ is not qualitatively similar among intra-acinar microvessels, in which COX- and NOS-associated vasoactive substances function differently.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

Mouse alloantigen Ly10 is identical to murine fusion regulatory protein-1 (mFRP-1)/4F2/CD98: aberrant expression of mFRP-1/Ly10 allotypes in cells derived from CDF1 mice due to the gene deletion.

Murine FRP-1 (mFRP-1) and Ly10 antigens are alloantigens. Anti-Ly10.1, monoclonal antibody (mAb) reacts to HeLa cells stably expressing mFRP-1.1 (HeLa cells/mFRP-1.1), but does not react to HeLa cells/ mFRP-1.2. On the other hand, anti-Ly10.2 mAb reacts to HeLa/mFRP-1.2 cells, but does not react to HeLa cells/mFRP-1.1. These findings indicate that Ly10.1 and Ly10.2 antigens are identical to the heavy chains of mFRP-1.1 and mFRP-1.2 molecules, respectively. Thymocytes and fibroblast cells obtained from CDF1 and BDF1 mice showed reactivity to both anti-Ly10.1 and anti-Ly10.2/FRP-2 antibodies, indicating that mFRP-1/Ly10 alloantigens are codominantly expressed in the F1 mice. Intriguingly, IMC carcinoma cells, derived from CDF1 mice, express mFRP-1.2, but do not express mFRP-1.1. Surprisingly, DBT cells, derived from CDF1 mice, consist of two different cell populations: one expresses both mFRP-1.1 and mFRP-1.2 antigens and the other expresses only mFRP-1.1 antigen. Consequently, we tried to isolate cloned DBT cell lines by limiting dilution. Finally, six cloned DBT cell lines were obtained, and three clones of these cloned DBT cells expressed both mFRP-1.1 and mFRP-1.2, and another three clones of these cloned DBT cells expressed both mFRP-1.1 and mFRP-1.2, and another three clones including clone 5 cells expressed only mFRP-1.1 antigen. No induction of mFRP-1.2/Ly10.2 by 5-azacytidine and sodium n-butyrate could be detected in DBT clone 5 cells. Neither mFRP-1.2 mRNA nor the genomic cDNA clone encoding mFRP-1.2 could be detected in DBT clone 5 cells, nor could the genomic cDNA encoding mFRP-1.1 be detected in IMC cells, indicating that aberrant expression of mFRP-1/Ly10 allotypes in CDF1 mice-derived cells is due to the gene deletion.

Animals↗
PubMed1998

Differential contribution of various adhesion molecules to leukocyte kinetics in pulmonary microvessels of hyperoxia-exposed rat lungs.

To elucidate the differential role of various adhesion molecules in distorting leukocyte behavior in the microvasculature of hyperoxia-exposed rat lungs, we investigated fluorescein-labeled leukocyte and erythrocyte kinetics in isolated lungs taken from the animals exposed to 90% O2 for 48 h under conditions in which endothelial intercellular adhesion molecule-1 (ICAM-1) and P-selectin were inhibited by appropriate monoclonal antibodies (1A29 for ICAM-1 and ARP2-4 for P-selectin), while leukocyte L-selectin was restrained with fucoidin. Measurements of blood cell kinetics were made by a confocal laser luminescence microscope coupled with a high-speed video camera. In addition, we histologically examined leukocyte accumulation within the alveolar septa and ICAM-1 as well as P-selectin expressions in the lung. We found that P-selectin expression was sparsely enhanced only in arterioles, whereas ICAM-1 was significantly induced in both venules and capillaries. Firm adhesion of leukocytes was not identified in arterioles and venules, whereas leukocyte rolling was evident in both the vessels. Arteriolar rolling was regulated via a P-selectin- and ICAM-1-independent but L-selectin-dependent mechanism, whereas venular rolling was mediated via a P-selectin-independent but ICAM-1- and L-selectin-dependent pathway. Leukocyte sequestration within capillaries was augmented by an ICAM-1-related mechanism. These findings may suggest that, in hyperoxia-exposed lungs, induction of adhesion molecules and their obstacles to leukocyte behavior are qualitatively different among arterioles, venules, and capillaries.

Animals↗
PubMed1998

Impaired hypoxic vasoconstriction in intraacinar microvasculature in hyperoxia-exposed rat lungs.

To assess the effects of exposure of the lung to hyperoxic conditions on reactivity of pulmonary microcirculation to hypoxic stimulation, we measured hypoxia-elicited overall pulmonary pressor changes (HPV) and microvascular diameter changes in intraacinar arterioles, venules, and capillaries in isolated perfused rat lungs exposed to a hyperoxic environment (90% O2). To estimate the importance of vasoactive prostaglandins and nitric oxide (NO) for HPV modification, we examined the roles of constitutive and inducible forms of cyclooxygenase (COX-1 and COX-2) and those of NO synthase (eNOS and iNOS). Indomethacin was used for inhibiting both COX-1 and COX-2, while NS-398 was used as a selective inhibitor of COX-2. Both eNOS and iNOS were suppressed by L-NAME, whereas iNOS alone was inhibited by aminoguanidine. Microvascular diameter was measured with a real-time confocal laser scanning luminescence microscope. We found that (1) exposure to hyperoxia caused overall HPV and arteriolar constriction to be attenuated; (2) the blunted HPV was restored by L-NAME but not by aminoguanidine, indomethacin, or NS-398; and (3) arteriolar constriction was improved by either L-NAME, aminoguanidine, or indomethacin but only slightly by NS-398. In conclusion, attenuation of overall HPV in hyperoxia-exposed lungs is explicable mainly by excessive NO generated via eNOS, while impaired arteriolar constriction is caused by NO yielded by eNOS and iNOS as well as by vasodilating prostaglandin(s) produced by COX-1.

Animals↗
PubMed1998

Detection of endogenous retrovirus antigens in NOD mouse pancreatic beta-cells.

We characterized C-type retroviruses expressed in the pancreatic beta-cells of non-obese diabetic (NOD) mice by immunohistochemical techniques and by inhibiting the production of viral particles using antisense oligonucleotides. Some cells in the pancreatic islets from both NOD and diabetes-resistant NOD-related mice (NON) reacted with a monoclonal antibody directed against the envelope protein(s) of polytropic viruses. On the other hand, NOD islet cells also showed strong immunoreactivity with an anti-gag protein monoclonal antibody and another anti-envelope protein(s) monoclonal antibody that is specific for xenotropic viruses. In antisense oligodeoxynucleotide inhibition assays, a xenotropic virus-specific phosphorothionate-particles antisense oligodeoxynucleotide significantly inhibited the occurrence of C-type virus particles in NOD mouse islet beta-cells. Therefore, C-type retrovirus-like particles expressed in NOD mouse pancreatic beta-cells were considered to be endogenous xenotropic virus. The expression of the xenotropic viral genome may be involved in the pathogenesis of the diabetic syndrome in NOD mice.

Animals↗
PubMed1998

Effects of spin labeled derivatives of podophyllotoxin on cell cycle and macromolecular synthesis in human lymphoid leukemia Molt 4B cells.

AIM: To examine the effect of the spin labeled derivatives of podophyllotoxin, N-podophyllic acid-N"-[4-(2,2,6,6-tetramethyl-1-piperidinyloxy)] thiosemicarbazide (GP4) and 4-[4"-(2",2",6",6"-tetramethyl-1"-piperidinyloxy) amino]-4'-demethylepipodophyllotoxin (GP7) on the cell cycle and macromolecular synthesis of human lymphoid leukemia Molt 4B cells in vitro. METHODS: MTT assay, 3H incorporation, and flow cytometer were used. RESULTS: GP4, GP7, and etoposide 0.02-100 mmol.L-1 cultured for 48 h inhibited the proliferation of human lymphoid leukemia Molt 4B cells. IC50 values of GP4, GP7, and etoposide were 0.11, 4.7, and 1.6 mmol.L-1, respectively. DNA and protein syntheses were obviously suppressed by GP4, GP7, and etoposide 10 mmol.L-1 for 48 h. After Molt 4B cells were treated with GP4, GP7, and etoposide 10 mmol.L-1 for 6 and 12 h, the mitotic index was increased by GP4 and reduced by GP7 and etoposide. According to flow cytometric BrdU/DNA analysis, GP4 slightly retarded S phase and mainly arrested cell cycle progression in G2/M phase, whereas GP7 similar to etoposide induced cells accumulated at S phase and retarded the cells in G2 phase. CONCLUSION: GP4 and GP7 inhibit the proliferation of Molt 4B cells, but the mechanisms are different.

Antineoplastic Agents, Phytogenic↗