Biomedical subjects

Y Komatsu

Publications and source records attributed to Y Komatsu.

At least 217 records · Page 12Linked to original sources

PubMed1996

[A study of serum protein fraction binding to indocyanine green (ICG) by combined method of immunoelectrophoresis and ICG fundus videosystem].

Binding characteristics of indocyanine green (ICG) to human serum were investigated, with a combination of immunoelectrophoresis and an ICG fundus video system. Serum samples were obtained from three healthy volunteers, 1 minute after intravenous administration of 50 mg/2 ml ICG, and then fractionated immunoelectrophoretically on agarose plates. Electrophoretic patterns on these plates could be observed with an ICG fundus video system as well as an immunoviewer. Using anti-human sera, only one infrared fluorescent line showing the ICG binding immunoprecipitate was recognized near the area of beta fraction, which was also identified by the use of anti-beta-lipoprotein (Lp) antibody. We also studied the affinity of ICG for apolipoproteins (Apo) AI, B, and CIII, which were the main protein components of serum Lps. Electrophoresis showed that ICG bound only to Apo-B, but not to the others. These results indicated that ICG mainly bound to beta-Lp in the blood, and that ICG angiographic patterns were directly reflecting the dynamics of serum Lps, especially for LDL. The high affinity of ICG for only Apo-B could explain the reason why ICG mainly bound to beta-Lp among several serum Lps, because large amounts of Apo-B are included in beta-Lp but a little in other serum Lps.

Apolipoproteins B↗

PubMed1996

Heat-shock treatment reduces in situ temperature in yeast at sub-lethal high temperature.

Cells from the yeast Schizosaccharomyces pombe IFO-0342, once heat shocked and then treated with ultra-centrifugation showed a significant increase in tolerance compared to non heat-shocked control cells as estimated by colony forming unit (CFU). Fluorescence microscopical observation of these treated cells when stained with DAPI revealed that in non heat-shocked cells the chromatin regions were dislocated to one end due to the acceleration force of gravity. However, prior heat-shocked cells or 2.0 M glycerol suspended cells showed normal localization. From these results, it has been postulated that the interior part of the heat-shocked cells becomes viscous, and that in situ the temperature of the cell interior part might be reduced under semi-lethal high temperature.

Hot Temperature↗

PubMed1995

Induction of heat-shock proteins and accumulation of trehalose by TPN in Saccharomyces cerevisiae.

TPN [Tetrachloroisophthalonitrile], a kind of disinfectant, affected growth in Saccharomyces cerevisiae. Exposed to TPN under no lethal conditions, 70-, 90-kDa protein and hsp104 were induced. Each of them was not uniformly induced; namely, the 70-kDa protein was more sensitive to TPN among other proteins. Trehalose was also accumulated depending on the concentration. The degree of thermotolerance in yeast cells pretreated with 1.0 mg/l TPN was about 100-fold greater than in the control. Under this condition, TPN-inducible proteins were synthesized but trehalose was not accumulated. Although TPN-inducible proteins and trehalose were definitely synthesized with 10.0 or 100.0mg/l TPN treatment, thermotolerance was not acquired.

Blotting, Western↗

PubMed1995

The amino acid sequence and interaction with the nucleosome core DNA of transition protein 4 from boar late spermatid nuclei.

The primary structure of transition protein 4 (TP4) from boar late spermatid nuclei was determined by automated Edman degradation of S-pyridylethylated protein and of peptides generated by cleavage with Staphylococcus aureus V8 protease, lysyl endopeptidase and CNBr. Boar TP4 is a basic protein consisting of a highly basic amino-terminal half (residues 1-73) and a less basic carboxy-terminal half (residues 74-138). The latter half includes a highly hydrophobic segment, a four-times tandemly repeated sequence, N(G)QNKR(K)X, and a carboxy-terminal segment containing Trp126. Ultraviolet absorption and CD spectra of TP4-rat-liver-nucleosome-core-DNA (double-stranded DNA) complexes suggest a TP4-induced local melting of DNA. Although at 1 mM NaCl TP4 brought about a slight stabilization of the DNA against thermal melting, a destabilization of the DNA was observed at 50 mM NaCl. From the results of quenching of tryptophan (Trp126) fluorescence of TP4 upon its binding to double-stranded and single-stranded boar liver nucleosome-core DNA at 50 mM NaCl, the apparent association constants for the binding of TP4 to double-stranded and single-stranded DNA were calculated to be 7.3 x 10(3) M-1 and 4.1 x 10(3) M-1, respectively. These results suggest that TP4, having different domain structures from TP1-3 and a higher affinity for double-stranded DNA, induces a local destabilization of DNA probably through the stacking of Trp126 with nucleic acid bases.

Amino Acid Sequence↗

PubMed1995

Modification of primary structures of hairpin ribozymes for probing active conformations.

Hairpin ribozymes consist of two stem-loop domains, and these domains are assumed to interact with each other to produce the self-cleavage activity. We have studied the relationship of the tertiary structure of the hairpin ribozyme and the cleavage activity by dividing and re-joining the domains. A hairpin ribozyme (E50) was divided at the hinge region, and the main part was joined to a substrate (S1) using tri- or penta-cytidylates. These ribozymes retained the cleavage activity in the presence of the rest of the molecule, indicating that the active conformation could be maintained if the two domains interacted with each other. Based on the these results, we designed a new type of hairpin ribozyme by replacing one of the domains. To maintain the interaction of the domains, oligocytidylates were inserted at a junction. These reversely jointed ribozyme complexes showed cleavage activity that was dependent on the linker lengths. These modifications in the primary structure of the hairpin ribozyme confirm the structural requirement for the catalytic reaction and provide information for the correlation of the tertiary structure with the cleavage of the hairpin ribozyme.

Base Sequence↗

PubMed1995

Mouse and human chromosomal assignments of mortalin, a novel member of the murine hsp70 family of proteins.

Mortalin has been shown to exhibit differential distributions in cells with mortal and immortal phenotypes. In the present study, we report mot-2 cDNA cloning from RS-4 cells--an immortal clone from CD1-ICR mouse embryonic fibroblasts--and the chromosomal assignments of mortalin related genes to mouse chromosomes 18 and X by fluorescence in situ hybridization. Similar analysis assigned the gene to chromosome 5q31.1 in human.

Animals↗

PubMed1995

Effect of splenectomy on hepatic metastasis of colon carcinoma and natural killer activity in the liver.

We have previously demonstrated that administration of killed streptococcal preparation (OK432), a biological modifier, increased the number of asialo GM1-positive cells in the liver, enhanced NK activity of hepatic mononuclear cells, and reduced the number of hepatic metastases of colon 38 adenocarcinoma that were inoculated into the superior mesenteric vein of C57BL/6 strain mice. In the present study, to clarify the role of the spleen in immune surveillance of the liver, the effect of splenectomy on hepatic metastasis of colon carcinoma and on hepatic NK activity has been examined. The number of hepatic metastasis increased in the splenectomized mice, compared with that in sham-operated mice. Administration of OK432 increased the number of asialo GM1-positive cells in the liver and enhanced NK activity of hepatic mononuclear cells in both groups, but NK activity of hepatic mononuclear cells in the splenectomized mice was less than that of the sham-operated mice. An enhanced NK activity of these cells was abolished by treatment with anti-asialo-GM1 antibody plus complement in vitro. Interleukin-2 mRNA expression was increased in the spleen 2 hr after OK432 administration and persisted until 8 hr, but was scarcely noted in the liver. On the other hand, NK activity of hepatic mononuclear cells in the asialo GM1-positive cell-depleted (previous administration of antiserum against asialo GM1) mice was enhanced after OK432 administration in the sham operated and splenectomized mice, but an enhanced NK activity in these mice was only partially or not at all abolished by treatment with anti-asialo GM1 antibody plus complement in vitro, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Occurrence of antibody against rat hepatic sinusoidal endothelial cells in sera of patients with autoimmune hepatitis.

To determine whether an antibody against hepatic sinusoidal endothelial cells was present in sera of patients with autoimmune hepatitis (AIH) type 1, we measured the serum IgG bound to the glutaraldehyde-fixed cultured rat sinusoidal endothelial cells by enzyme-linked immunosorbent assay. IgG bound to the cells was detected significantly more in patients with autoimmune hepatitis type 1 (97.1%) than in those with primary biliary cirrhosis (13.0%), chronic hepatitis C (5.9%) or B (7.9%), or healthy controls (0%). IgG-F(ab')2 fragments from autoimmune hepatitis patients also bound to the cells, and this binding was observed after absorption of the fragments with rat hepatoma cells, but not after absorption with bovine carotid endothelial cells. Culture of sinusoidal endothelial cells in the presence of IgG from AIH patients significantly reduced the number of viable attached cells. In conclusion, anti-sinusoidal endothelial cell antibody occurred in the sera from patients with autoimmune hepatitis type 1.

Animals↗

PubMed1995

Macrophages in childhood IgA nephropathy.

The role of glomerular macrophages in IgA nephropathy in children was investigated using a new monoclonal antibody (KP1) as a probe. The average number of glomerular macrophages per patient (ANM/P) was closely correlated with the degree of hematuria (P < 0.01) as well as with the degree of leukocyturia (P < 0.01) in the absence of any correlation with proteinuria, serum IgA levels or the interval between the detection of urine abnormalities and renal biopsy. ANM/P was significantly higher in patients diagnosed pathologically as having focal and diffuse proliferative glomerulonephritis than in patients with minor glomerular abnormalities or advanced sclerosis (P < 0.05). Among various types of glomerular morphology in individual patients, macrophages predominantly infiltrated glomeruli with cell-proliferative lesions despite an absence of any increase in glomeruli with minor abnormalities or with sclerosis. Macrophages were mainly localized within the capillary lumen in association with endocapillary proliferative lesions (tuft necrosis), they accumulated in areas of mesangial proliferation, and they were attached to Bowman's capsule in segmental lesions. Macrophages were less evident in sclerosis. Furthermore, ultrastructural analysis revealed macrophages in the paramesangial areas in close proximity to lytic changes in the glomerular basement membrane and effacement of epithelial foot processes. In addition, some cases in repeat biopsy shows prolonged or increased values of ANM/P after several years of interval in association with progression of proliferative lesions. These results suggest that macrophages infiltrate glomeruli during acute glomerular inflammation, and that they are involved in mesangial proliferation or the development of extracapillary lesions in the absence of apparent clinical symptoms. Furthermore, recurrence or prolonged infiltration may promote progression of IgA nephropathy.

Antibodies, Monoclonal↗

PubMed1995

Effect of oral administration of a pectic polysaccharide fraction from a kampo (Japanese herbal) medicine "juzen-taiho-to" on antibody response of mice.

A dried decoction of a kampo (Japanese herbal) medicine, Juzen-Taiho-To (TJ-48), has been fractionated into five fractions and tested for their effects on antibody response of mice. An intraperitoneal injection (300 mg/kg) of TJ-48 stimulated anti-sheep red blood cell (SRBC) antibody response of normal Balb/c mice, but only the polysaccharide fraction (F-5, 300 mg/kg) enhanced the antibody response among the fractions from TJ-48. When F-5 (0.5 or 1.0 g/kg/day) was orally administered to normal Balb/c mice (7-weeks-old) from 7 days before to 4 days after immunization with SRBC, the number of anti-SRBC-IgM-PFC in spleen and the titer of anti-SRBC-IgM in plasma were increased significantly. However, a lower dose (0.1 g/kg/day) of F-5 did not show a significant stimulative activity on the anti-SRBC-response. Although aged Balb/c mice (6-months-old) produced a lower level of anti-SRBC-IgG in comparison with young Balb/c mice (8-weeks-old), the anti-SRBC-IgG response of the aged mice was stimulated significantly when F-5 (0.13 g/kg/day) or TJ-48 (1.0 g/kg/day) was orally administered to the aged mice from 6 days before immunization. Intraperitoneal injections of i-carrageenan (2.5 mg/kg/day) at 3 and 1 days before the immunization with SRBC increased the level of anti-SRBC antibody response compared with normal mice. Oral administrations of TJ-48 (1.0 g/kg/day) or F-5 (0.5 g/kg/day) to the i-carageenan-treated mice reduced the level of the anti-SRBC-antibody response near to that of normal mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗

PubMed1995

Protective effect of oral administration of a pectic polysaccharide fraction from a Kampo (Japanese herbal) medicine "Juzen-Taiho-To" on adverse effects of cis-diaminedichloroplatinum.

A dried decoction of a kampo (Japanese herbal) medicine, Juzen-Taiho-To (TJ-48) has been fractionated into five fractions, which have each been tested for their protective effects on the lethal and renal toxicities of cis-diaminedichloroplatinum (CDDP) in mice. The survival rate of CDDP-treated ICR mice was increased by oral administration of the pectic polysaccharide fraction (F-5), whereas the mortality of the CDDP-treated mice was not changed by the oral administration of methanol-soluble fraction (F-1). When methanol-soluble substances were removed from TJ-48, it showed a similar protective activity on the lethal toxicity of CDDP. Oral administrations of F-5 (130 mg/kg/day) as well as TJ-48 (1 g/kg/day) decreased the level of blood urea nitrogen (BUN) in plasma of CDDP-treated Balb/c mice. All other fractions of TJ-48 also decreased the level of BUN. Although F-5 has been fractionated into the acidic (F-5-2) and neutral polysaccharide fractions (F-5-5), oral administration of only F-5-2 (at dose of 100 mg/kg/day) decreased the level of BUN in the CDDP-treated mice.

Administration, Oral↗

PubMed1995

Structural composition of hammerhead ribozymes.

Eleven kinds of hammerhead ribozymes were designed and synthesized to investigate the structural composition of the complexes and to find suitable crystallization conditions, the substrate chains having been modified to prevent hydrolysis. Electrophoresis patterns indicated that the two strands except for the substrate chain form a binary complex and that they form a ternary complex when mixed with the substrate chain. Both complexes were crystallized. The crystal of the binary complex belongs to a Laue symmetry of 32 (space group of P321, P3(1)21, or P3(2)21) with cell dimensions of a = b = 53.4 and c = 59.4 A. The volume per one nucleotide allows the asymmetric unit to contain one binary complex. Our results suggest that the catalytic part forms a rigid ribozyme structure which induces a scissile reaction when the substrate is bound, in a similar manner to an enzyme protein.

Base Sequence↗

PubMed1995

Gene regulation of brain natriuretic peptide in cardiocyte hypertrophy by alpha1-adrenergic stimulation.

1. We previously demonstrated that brain natriuretic peptide (BNP) is a cardiac hormone mainly produced in the ventricle, while the major production site of atrial natriuretic peptide (ANP) is the atrium. The production and secretion of BNP and ANP in the hypertrophied ventricles were markedly augmented, serving as a compensation mechanism against ventricular overload by their natriuretic, diuretic and vasodilatory actions. 2. In the present study, we prepared an in vitro model of cardiocyte hypertrophy using cultured neonatal rat ventricular cardiocytes and alpha1-adrenergic stimulation, and examined the gene expressions of BNP and ANP during the process of cardiocyte hypertrophy. 3. The treatment of cultured ventricular cardiocytes with phenylephrine evoked cardiocyte hypertrophy around 24 h after the treatment, which was characterized by augmented expression of the myosin light chain-2 gene and increase in cell size. 4. In this model of cardiocyte hypertrophy, the steady-state level of BNP mRNA rapidly increased to the maximal level within 1 h after the treatment. In contrast, ANP mRNA began to increase at 3 h, and accumulated during the course of cardiocyte hypertrophy. The secretion of BNP from ventricular cardiocytes was also stimulated more rapidly than the ANP secretion. 5. These results indicate that the gene expression of BNP is distinctly regulated from that of ANP in cardiocyte hypertrophy, and suggest a discrete pathophysiological role of BNP as an 'emergency' cardiac hormone against ventricular overload.

Adrenergic alpha-1 Receptor Agonists↗

PubMed1995

Endothelin-induced activation of mitogen-activated protein kinases in glomerular mesangial cells from normotensive and stroke-prone spontaneously hypertensive rats.

1. Kinase assay in myelin basic protein (MBP) containing polyacrylamide gels revealed that endothelin-1 (ET-1) and ET-3 increased MBP kinase activities in glomerular mesangial cells (MC) from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rat (SHRSP). ET-1 stimulated MBP kinase activities more potently than ET-3. 2. Immunoprecipitation with anti-41-kDa MAPK antiserum showed that the MBP kinases activated by ET-1 correspond to 43- and 41-kDa MAPK. 3. Since Phorbol 12-myristate 13-acetate, a direct activator of protein kinase C, also activated MAPK, protein kinase C was suggested to mediate ET-induced activation of MAPK. 4. These results suggest that MAPK may mediate the ET actions in glomerular mesangial cells from normotensive rats as well as spontaneously hypertensive rats. Since ET is produced by vascular endothelial cells of the kidney and glomerular mesangial cells, the ET signalling pathway may have some physiological and pathophysiological significance in vivo glomerulus.

Animals↗

PubMed1995

Endotoxin induced cellular communication in the liver: murine models for clarification of the role of LPS-responsive macrophages in the pathogenesis of liver diseases.

In several experimental models, lipopolysaccharide (LPS) plays an important role in the pathogenesis of liver diseases. Murine models of C3H/HeN and C3H/HeJ mice have been used to elucidate the role of LPS and its responsive-macrophages in vivo, as C3H/HeN strain mice are known to be LPS-responsive, while C3H/HeJ strain mice are LPS-resistant. Furthermore, release of several kinds of biologically active mediators such as interleukin-1, tumour necrosis factor-alpha, colony stimulating factor and reactive oxygen radical is not enhanced in C3H/HeJ mice even after stimulation with LPS. Thus, these murine models could be suitable for clarification of endotoxin induced cellular communication in the liver.

Animals↗

PubMed1995

Mitosis and the presence of binucleate cells among glomerular podocytes in diseased human kidneys.

Podocytes are highly differentiated cells that appear to be postmitotic. However, it is unclear whether cell division or the proliferation of podocytes takes place in the setting of glomerular injury. In this study, we analyzed the presence of mitotic figures and of binucleate or multinucleate podocytes in diseased human kidneys by light and electron microscopy. Among the 164 cases analyzed, mitotic figures in podocytes were found in only one cell, in a case of focal and segmental glomerulosclerosis, and 6 cases provided evidence of two or more nuclei in a single podocyte. Serial sections by light microscopy confirmed that the nuclei in multinucleate cells were separate and of approximately the same size. Electron-microscopic analysis of the binucleate podocytes revealed hypertrophy and effacement of foot processes. These findings indicate that, in human podocytes, mitosis without cytokinesis (cell division) results in binucleate cells in cases of glomerular injury.

Biopsy↗

PubMed1995

Rapid transcriptional activation and early mRNA turnover of brain natriuretic peptide in cardiocyte hypertrophy. Evidence for brain natriuretic peptide as an "emergency" cardiac hormone against ventricular overload.

We previously demonstrated that brain natriuretic peptide (BNP) is a cardiac hormone mainly produced in the ventricle, while the major production site of atrial natriuretic peptide (ANP) is the atrium. To assess the pathophysiological role of BNP in ventricular overload, we have examined the gene expression of BNP, In comparison with that of ANP, in a model of cardiac hypertrophy using cultured neonatal rat ventricular cardiocytes. During cardiocyte hypertrophy evoked by endothelin-1, Phenylephrine, or PMA, the steady state level of BNP mRNA increased as rapidly as the "immediate-early" induction of the c-fos gene expression, and reached a maximal level within 1 h. Actinomycin D, a transcriptional inhibitor, completely diminished the response, while the translational blocked with cycloheximide did not inhibit it. In contrast, ANP mRNA began to increase 3 h after the stimulation, and accumulated during cardiocyte hypertrophy. The BNP secretion from ventricular cardiocytes was also stimulated, more rapidly than the ANP secretion. Furthermore, the turnover of BNP mRNA was significantly faster than that of ANP mRNA, being consistent with the existence of AUUUA motif in the 3'-untranslated region of BNP mRNA. These results demonstrate that the gene expression of BNP is distinctly regulated from that of ANP at transcriptional and posttranscriptional levels, and indicate that the characteristics of the BNP gene expression are suitable for its possible role as an " emergency" cardiac hormone against ventricular overload.

Animals↗

PubMed1995

Synthesis of a novel dual inhibitor of thromboxane A2 synthetase and 5-lipoxygenase (E3040) via the direct coupling reaction of hydroquinone with 3-pyridinecarboxaldehyde.

Synthesis of a novel dual inhibitor of thromboxane A2 synthetase and 5-lipoxygenase, 5,7-dimethyl-6-hydroxy-2-methylamino-4-(3- pyridylmethyl)benzothiazole (E3040), was accomplished via a new coupling reaction, in which a key intermediate, (3,6-dihydroxy-2,4-dimethylphenyl)-(3-pyridyl)methanol, was easily synthesized in a high yield from 2,6-dimethyl-1,4-benzohydroquinone and 3-pyridinecarboxaldehyde in 6 N hydrochloric acid. The regio isomers of 3-pyridinecarboxaldehyde also gave the corresponding coupling products in high yields.

Benzothiazoles↗