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Biomedical subjects

A Kawamura

Publications and source records attributed to A Kawamura.

At least 145 records · Page 8Linked to original sources
PubMed1991

Expression and distribution of atrial natriuretic peptide in human hypertrophic ventricle of hypertensive hearts and hearts with hypertrophic cardiomyopathy.

To investigate the ventricular expression of atrial natriuretic peptide (ANP) in human hypertrophic hearts, we conducted an immunohistochemical study of 130 endomyocardial biopsy specimens obtained from the right side of the ventricular septum (RVB), left ventricular free wall (LVB), or both from a total of 80 patients: 44 patients with hypertrophic cardiomyopathy (HCM), 14 with apical hypertrophic cardiomyopathy (APH), 13 with hypertensive hearts (HHD), and nine without hypertrophy (controls). No patients had apparent congestive heart failure. ANP was not seen in ventricular myocytes in controls but was identified in biopsy specimens of hypertrophic hearts, and its distribution was characteristic in each hypertrophic group: 15 RVB (37%) and two LVB (7%) of the HCM group, one RVB (7%) and two LVB (18%) of the APH group, and zero RVB (0%) and five LVB (46%) of the HHD group. Clinical data (including echocardiographic, hemodynamic, and angiographic data) were not directly related to ventricular ANP expression in HCM, APH, or HHD with one exception. In HHD patients, LVB specimens with ANP showed greater ventricular wall thickness than LVB specimens without ANP. According to histological data, however, the ANP-present RVB specimens of HCM or ANP-present LVB specimens of HHD had greater myocyte size than did the ANP-absent specimens. In addition, in HCM patients, the ANP-present RVB specimens showed more severe fibrosis and myofiber disarray than did the ANP-absent specimens. We conclude that a failing state and hemodynamic overload are not likely to be indispensable for ANP expression in human hypertrophic ventricles and that ventricular ANP expression occurs as a response to disease-specific changes: hemodynamic overload in HHD and histological changes such as myocardial fiber disarray, hypertrophy of myocytes, and fibrosis in HCM, which may reflect the characteristic distribution of intraventricular ANP.

Adult↗
PubMed1991

Relation between myoglobin and cardiac dysfunction in myocarditis--immunohistochemical study of endomyocardial biopsy specimens.

To investigate the mechanism of cardiac dysfunction in myocarditis, myoglobin, an intracellular oxygen-transport, was immunohistochemically examined in biopsy specimens obtained from the right side of the ventricular septum and left ventricular free wall in 58 patients with myocarditis and 19 controls. Sections 4 microns thick were stained by the indirect immunoperoxidase method using a polyclonal antibody to human myoglobin as the primary antibody. Under light microscopy, the intensity of myoglobin immunoreactivity in the tissue section was semiquantitatively classified from grade 0 to grade 3. Then, the grade of myoglobin staining was compared with clinical, hemodynamic and histopathologic parameters. In right and left ventricular specimens, the grade of myoglobin staining was positively correlated with ejection fraction, but inversely with left ventricular end-diastolic and end-systolic volume indices. The percentage of myocytes with grade 0 was correlated with the number of mononuclear cells in the specimens. In addition, the grade of myoglobin staining in right ventricular specimens was positively correlated with the duration of illness but inversely correlated with the number of mononuclear cells. In 4 patients who had serial biopsies, the ejection fraction was improved and the grade of myoglobin staining was increased in the convalescent stage. These results indicate that myoglobin staining reflects the intensity of myocarditis and a decrease of myoglobin may be important as one of the pathogenetic factors of cardiac dysfunction in myocarditis.

Adolescent↗
PubMed1991

Effects of recombinant human granulocyte colony-stimulating factor on neutrophil function in normal rats.

We studied the effects of recombinant human granulocyte colony-stimulating factor (rG-CSF) on neutrophil functions in vitro using neutrophils isolated from the venous blood of normal rats. FMLP-induced superoxide anion (O2-) release, phagocytosis, and FMLP-induced chemotaxis were evaluated. These functions were significantly enhanced by rG-CSF treatment. In addition to performing neutrophil function assays, we evaluated FMLP binding to rat neutrophils after rG-CSF treatment. FMLP specific binding was not changed by rG-CSF treatment. In addition, we intravenously injected rG-CSF (10 micrograms/kg) or control vehicle into rats for 7 consecutive days, and evaluated the functions of neutrophils isolated from venous blood at 6 h after the final injection. The neutrophil count in the peripheral blood of rG-CSF-treated rats was increased significantly compared with that in control rats. FMLP-induced O2- release, phagocytosis, FMLP-induced chemotaxis and spontaneous migration of rG-CSF-treated neutrophils were significantly enhanced in comparison with those in control rats. These findings demonstrate that rG-CSF not only increases neutrophil counts in peripheral blood, but that it also enhances neutrophil functions, both in vitro and in vivo.

Animals↗
PubMed1990

Physicochemical and biological characterization of asialoerythropoietin. Suppressive effects of sialic acid in the expression of biological activity of human erythropoietin in vitro.

Various partially or fully desialylated human erythropoietins were obtained by neuraminidase digestion of the hormone, without non-specific proteolysis and degradation of carbohydrates. Asialoerythropoietin showed a specific activity of 220-IU/mg protein in vivo, although that of the intact erythropoietin was 2.2 x 10(5) IU/mg. A linear relationship was found between the logarithm of the specific activity in vivo and the number of sialic acids. The asialoerythropoietin showed a four-times-higher specific activity in vitro compared with intact erythropoietin using mouse bone marrow cells. It also showed an approximately six-times-higher specific activity in a colony-forming assay for the erythroid colony-forming unit and the erythroid burst-forming unit. Partially or fully de-N-glycosylated erythropoietin derivatives also showed lower in vivo activity but higher in vitro activity than the intact erythropoietin, dependent on the number of sialic acids. To clarify the reason for the enhanced biological activity of asialoerythropoietin in vitro, the binding of intact 125I-erythropoietin or 125I-asialoerythropoietin to cells containing specific receptors for the hormone was analyzed. 125I-asialoerythropoietin bound to spleen cells from anemic mice approximately five times faster than did intact 125I-erythropoietin. The amount of 125I-asialoerythropoietin internalized by target cells, measured in the absence of NaN3, was four times higher than that of intact erythropoietin. These results demonstrate that asialoerythropoietin binds to its receptor faster than the intact form. This may be the main reason for the increased activity of asialoerythropoietin in vitro.

Animals↗
PubMed1990

Secretion of killer toxin encoded on the linear DNA plasmid pGKL1 from Saccharomyces cerevisiae.

By the kar1-mediated cytoduction, linear double-stranded DNA plasmids pGKL1 and pGKL2, encoding killer toxin complex, have been successfully transferred to the recipient strains with about 30% frequency. The killer toxin was found to be secreted through the normal yeast secretory pathway by introducing pGKL plasmids into the several Saccharomyces cerevisiae sec mutants and examining the secretion of killer toxin. S. cerevisiae cells, harboring newly isolated deletion plasmid pGKL1D, expressed only the 28K protein among three killer subunits, and secreted the 28K subunit at a level of zero to 20% efficiency of the cells containing intact pGKL1 plasmid. These data indicated that subunit interaction (cosecretion) of killer proteins is required for the efficient secretion of 28K subunit. The 28K precursor protein was found to translocate across the canine pancreatic endoplasmic reticulum membrane under the direction of its own signal peptide in vitro without any other subunits. From kex2 mutant cells harboring pGKL1 plasmid, the 97K subunit, and its precursor 128K protein were not secreted, however, the 28K subunit was secreted in the same amount as that secreted from KEX2 cells. These lines of evidence suggest that the final assembly of killer toxin complex after KEX2 site of Golgi apparatus is not essential for the secretion of 28K subunit, and therefore, that putative interaction between 128K protein and 28K subunit for the transport between endoplasmic reticulum and Golgi apparatus may be required for the efficient secretion of 28K subunit.

Animals↗
PubMed1990

A monoclonal antibody to free N-acetylneuraminic acid.

A monoclonal antibody (70-A) to free N-acetylneuraminic acid was obtained by immunizing mice with its synthetic beta-glycoside, sodium O-[(5-acetamido-3,5-dideoxy-D-glycero-beta-D-galacto-2- nonulopyranosyl)onate]-(2----3)-1,2-di-O-tetradecyl-sn-glyce rol, followed by fusing the isolated spleen cells with mouse myeloma cells and cloning positive fusions. 70-A reacted with various synthetic beta-glycosides of N-acetylneuraminic acid and also with cytidine-5'-monophosphate-N- acetylneuraminic acid, known as its sole naturally occurring beta-glycoside. The inhibition assay showed that N-glycolylneuraminic acid had slightly lower reactivity than N-acetylneuraminic acid, but other monosaccharides tested, such as N-acetylglucosamine, N-acetylgalactosamine or N-acetylmannosamine, had no reactivity toward 70-A. Reactivity of 70-A with free N-acetylneuraminic acid was confirmed by measuring the specific binding of N-[14C]acetylneuraminic acid to the antibody. The association constant of 70-A with N-acetylneuraminic acid was determined to be 5.96.10(4) M-1 by equilibrium dialysis.

Animals↗
PubMed1990

Effect of purified recombinant human erythropoietin on anemia in rats with experimental renal failure induced by five-sixth nephrectomy.

Recombinant human erythropoietin (rHuEPO) was purified from the conditioned media of Chinese hamster ovary cells with a transfected human erythropoietin gene. We investigated the effects of the rHuEPO in rats with renal anemia induced by partial nephrectomy. Five-sixth nephrectomy resulted in renal failure with anemia. Twenty-five days after the operation plasma urea nitrogen was increased about 2.5 times, and the red blood cell count, hematocrit, and hemoglobin concentration fell to 85% of normal. The reticulocyte count and plasma erythropoietin level did not change such as they do in patients with anemia due to chronic renal failure. Both total red blood cell volume and the plasma iron turnover rate were depressed in five-sixth nephrectomized rats compared with normal rats. The five-sixth nephrectomized rats were injected with rHuEPO (60 IU/kg) intravenously every second day for a total of six injections. After three injections of rHuEPO, circulation volume of total red blood cells was increased from 9.9 ml to 14.6 ml, and the plasma iron turnover rate was increased from 1.03 mg/kg/day to 2.12 mg/kg/day, and the reticulocyte count was also increased. After six injections, a marked increase of the red blood cell count, hematocrit, and hemoglobin concentration were observed. Plasma urea nitrogen and the creatinine levels as indications for renal function did not change after rHuEPO administration in both normal and five-sixth nephrectomized rats. In conclusion rHuEPO has a potent erythropoietic action and it is possible to cure the anemia caused by renal failure.

Anemia↗
PubMed1990

Clinicopathological study of myocardial infarction with normal or nearly normal extracardiac coronary arteries. Quantitative analysis of contraction band necrosis, coagulation necrosis, hemorrhage, and infarct size.

In order to clarify the pathogenesis of acute myocardial infarction (MI) in hearts with normal coronary arteries, infarct size, and the extent of contraction band necrosis (CBN), coagulation necrosis, and hemorrhage were quantitatively examined using an image analyzer in 5 autopsy cases of MI with normal or nearly normal extracardiac coronary arteries. One patient died 40 h after acute MI. A second patient with acute MI due to severe spasm of segment 6, confirmed by cineangiography, died three days later. The third patient had already suffered a subarachnoid hemorrhage, and died 10 h after the onset of acute MI. The fourth patient had aortic stenosis and regurgitation. She developed acute MI due to total occlusion of segment 6, confirmed by cineangiography 4 h after the onset, and died 61 days later. Autopsy revealed old anteroseptal MI with normal coronary arteries and valvular thrombi. The fifth patient had a malignancy, and died one day after the onset of acute MI. Autopsy revealed multiple occlusive thrombi in the small intramural coronary arteries of the left ventricular wall supplied by segment 14, without any stenosis in the feeding vessel. Most infarcts were localized in the territory supplied by 1 or 2 of the 3 epicardial coronary arteries, and coincided with the clinically diagnosed infarct site. The infarct size ranged from 3%-26% of the left ventricular wall, and infarcts were generally localized to the inner third of the wall (67 +/- 20%). Histological examination of the four patients with acute MI revealed diffuse CBN (86 +/- 14% of the infarcted area) and/or hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Protective effects of nipradilol, isosorbide dinitrate, and bunazosin on coronary artery constriction induced by intracoronary injection of acetylcholine in pigs.

STUDY OBJECTIVE: Protective effects of nipradilol, a newly synthesised vasodilating beta adrenoceptor antagonist, isosorbide dinitrate, and bunazosin on coronary artery constriction induced by intracoronary injection of acetylcholine were determined by coronary arteriography and compared in vivo in pigs. DESIGN: Acetylcholine (12.5, 25, 50, 100 and 200 micrograms) was given into the right coronary artery under left ventricular pacing to maintain constant systemic haemodynamics. Percentage narrowing of the major epicardial coronary artery was used as an indicator of constriction of the large coronary arteries, and the time required for the contrast medium to reach the posterior descending coronary artery from the ostium of the right coronary artery (blood flow delay) was used as an indicator of constriction of the small coronary arteries. SUBJECTS: 15 farm pigs weighing 80 to 90 kg were used. MEASUREMENTS AND MAIN RESULTS: A marked blood flow delay of over 7.0 s (control: less than or equal to 1.8 s) with less than 34% narrowing of the epicardial major coronary artery was observed in 13 of 15 pigs with 12.5-50 micrograms of acetylcholine, and in the other two pigs with 100 micrograms of acetylcholine. When marked blood flow delay occurred, the perfused right ventricular myocardium became macroscopically anaemic (ischaemic). Over 75% narrowing of the major epicardial coronary artery was induced in six of the 15 pigs, and over 50% narrowing in 12, with marked blood flow delay with 100 to 200 micrograms of acetylcholine. However, after intracoronary infusion of 10 micrograms of nipradilol, acetylcholine induced narrowing in the epicardial major coronary artery was significantly reduced from 44-79% in control to 19-37% despite 200 micrograms of acetylcholine, though the time delay in coronary blood flow did not change significantly. By pretreatment with intracoronary isosorbide dinitrate (2.5 mg), the percent narrowing of the large coronary artery and the time delay in coronary blood flow were significantly reduced (narrowing from 32-84% to 10-27%; time delay from 7.6-41.6 s to 2.7-22.7 s). Pretreatment with intracoronary bunazosin, an alpha 1 adrenoceptor antagonist (100 micrograms), showed no protective effect on narrowing of the epicardial major coronary artery or blood flow delay. CONCLUSIONS: Isosorbide dinitrate prevents coronary artery constriction induced by acetylcholine in swine. Nipradilol prevents large, but not small, coronary artery constriction, probably through a direct nitrate like vasodilating action.

Acetylcholine↗
PubMed1990

Physicochemical and biological comparison of recombinant human erythropoietin with human urinary erythropoietin.

Physicochemical and biological properties of recombinant human erythropoietin (rhEPO) were compared with human urinary erythropoietin (uEPO). uEPO and rhEPO were purified to apparent homogeneity from the urine of patients with aplastic anemia and from the conditioned medium of Chinese hamster ovary (CHO) cells transfected with a cDNA clone for human EPO, respectively. The microheterogeneous nature of both factors, observed on isoelectric focusing, is derived from the difference of the number of terminal sialic acid residues bound to the carbohydrate chains of the EPO molecule. The primary structure of rhEPO, consisting of 165 amino acid residues, was determined, and the C-terminal arginine predicted from the cDNA sequence was confirmed to be missing, as described previously (Recny et al. (1987) J. Biol. Chem. 262, 17156). Three N-glycosylation and one O-glycosylation sites of both factors were determined as Asn24, Asn38, and Asn83 and Ser126, respectively. Two disulfide linkages are located between Cys7 and Cys161, and between Cys29 and Cys33, in both EPOs. Hematogenic potencies of rhEPO and uEPO compared in normal and in partially nephrectomized rats were approximately the same. Both factors also stimulated the colony formation of CFU-E, BFU-E, and CFU-Meg in a dose-dependent manner. From these results, it is concluded that rhEPO produced in CHO cells transfected with cDNA clone for human EPO is indistinguishable from uEPO physicochemically and biologically, and is valuable for further research and for clinical use.

Amino Acid Sequence↗
PubMed1990

[Relationship between the total IgE levels and specific IgE antibodies].

In this study, nine allergens were selected; i.e. 1289 cases of d1, 1277 cases of e1, 1547 cases of f1, 1063 cases of t17 and others, for investigating the relationship between the total IgE level and RAST score. The results showed that the total IgE level was high in high d1 score, and 29 cases of low IgE level were observed in high f1 score groups. On the other hand, the comparison of the CAP system and the total IgE level showed. The result shows that one case of low total IgE value was found in highest d1 score group.

Allergens↗
PubMed1990

Transmission of Rickettsia tsutsugamushi from Apodemus speciosus, a wild rodent, to larval trombiculid mites during the feeding process.

Transmission of Rickettsia tsutsugamushi (Rt) from a rodent to trombiculid mites was studied. Wild rodents, Apodemus speciosus, were subcutaneously inoculated with Karp strain of Rt, and larval trombiculid mites were released on the ear lobes for feeding, 10 and 20 days after infection. Isolation of Rt was performed from individual mites or pools of 2 to 7 mites by the mouse passage method. From Apodemus 10 days after Rt infection, possibly at the time of high rickettsiaemia, the infection rates among mites were 4/44 (9.1%) or higher in Leptotrombidium fuji, 1/20 (5%) in L. pallidum and 0/41 in L. deliense. From Apodemus 20 days after infection, no mite was infected in 50 L. fuji or 7 L. pallidum possibly due to reduced rickettsiaemia. Transmission of Rt from rodent to mite was proven to occur at low probability on appropriate conditions but not by the incidental chance.

Animals↗