Efficacy of a new immunosuppressant, CAM, on small bowel transplantation in rats.
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Animals↗
Biomedical subjects
H Sawada
Publications and source records attributed to H Sawada.
[Nonrheumatic calcification of the mitral valve in patients with stenotic calcified bicuspid aortic valve].
The pathogenesis of nonrheumatic calcification of the mitral valve was investigated by analyzing the clinical and echocardiographic characteristics of patients with mitral valvular calcification without any findings suggestive of rheumatic heart disease or infective endocarditis. Calcification of the mitral valve was observed in nine patients, who all had calcified stenotic (aortic valve area < 1 cm2) bicuspid aortic valve. Calcification of the mitral valve was localized to the basal portion of ventricular aspect of the anterior mitral leaflet and contiguous to that of the aortic valve. Mobility and thickness of the mitral leaflet was normal except for the calcified portion. Calcification of the mitral valve was not contiguous to posterior mitral annular calcification nor was related to direction of aortic regurgitant flow. In patients with calcified stenotic bicuspid aortic valve, calcification of the mitral valve was not associated with location of the two aortic cusps, aortic valve area, aortic valvular peak pressure gradient, direction of the left ventricular outflow, end-diastolic left ventricular outflow tract dimension, end-diastolic dimension of the aortic annulus, incidence of aortic regurgitation, calcification of the aortic arch, or risk factors of atherosclerosis. Six patients with mitral valvular calcification had aortic valve replacement. Preoperative coronary angiogram of these patients was normal. Calcification of the aortic valve was on the ventricular and aortic aspects. The calcification of the aortic valve, anterior mitral ring, or anterior mitral leaflet was not rheumatic in these six patients. Rheumatic disease, risk factors of atherosclerosis, mechanical stress by left ventricular outflow or aortic regurgitant flow, or mitral annular calcification did not appear to be related to mitral valvular calcification. The distribution of aortic and mitral valvular calcification suggested that the calcification of the mitral valve was due to progression of calcification of the bicuspid aortic valve.
Aged↗
[Preliminary screening for antiviral AIDS drugs. VI. Report for fiscal year 1993].
Preliminary screening of antiviral AIDS drugs has been carried out using three different in vitro assay systems. Among 138 samples tested, two were found to inhibit the growth of HIV in vitro. Neither of the positive samples has hopeful signs, as the ranges of effective doses of the samples are very narrow.
Anti-HIV Agents↗
[Preliminary screening for antiviral AIDS drugs. VII. Report for fiscal year 1994].
Preliminary screening of antiviral AIDS drugs has been carried out using three different in vitro assay systems. Among 246 samples of different origin tested, six were shown to inhibit the growth of HIV in vitro. Two of the positive samples have hopeful signs, as the ranges of effective doses are wider than those of most of positive samples which had been found by us.
Anti-HIV Agents↗
Regulatory subunit complex dissociated from 26S proteasome: isolation and characterization.
A ubiquitin (Ub)/ATP-dependent proteolytic complex (26S proteasome) purified from rabbit skeletal muscle was dissociated into two subcomplexes, a 20S proteasome and a regulatory subunit complex, by preparative non-denaturing polyacrylamide gel electrophoresis (PAGE). The isolated regulatory subunit complex preparation gave a single broad band on analytical non-denaturing PAGE, and several bands ranging between 33 and 110 kDa on SDS-PAGE. This complex was found to consist of about 20 subunits on the basis of two-dimensional PAGE, the pattern of which appeared identical or very similar to that of the 33-110 kDa 26S proteasome subunits. The apparent molecular mass of the complex was estimated to be 1100 kDa by Ferguson plot analysis and also by Superose 6 gel filtration. Unlike the 26S proteasome, neither ATPase activity nor protease activities toward Suc-Leu-Leu-Val-Tyr-MCA, Boc-Phe-Ser-Arg-MCA, Z-Leu-Leu-Glu-beta NA, [14C]-casein, [125I]-lysozyme and Ub-[125I]-lysozyme were significantly detectable in the regulatory subunit complex. This complex was found to be capable of associating with itself in MgATP-dependent manner. These results suggest that a regulatory subunit complex dissociated from the 26S proteasome comprises all the higher molecular mass subunits of the 26S proteasome, and has no detectable ATPase and protease activities, although the homo-oligomerization occurs in an ATP-dependent fashion.
Amino Acid Sequence↗
Targeted disruption of the tyrosine hydroxylase locus results in severe catecholamine depletion and perinatal lethality in mice.
Tyrosine 3-hydroxylase (TH, EC 1.14.16.2) catalyzes the first and rate-limiting step of the catecholamine biosynthetic pathway in the nervous and endocrine systems. The TH locus was disrupted in mouse embryonic stem cells by homologous recombination. Mice heterozygous for the TH mutation were apparently normal. In these mice, TH activity in the embryos and adult tissues was less than 50% of the wild-type values, but the catecholamine level was decreased only moderately in the developing animals and was maintained normally at adulthood, suggesting the presence of a regulatory mechanism for ensuring the proper catecholamine level during animal development. In contrast, the homozygous mutant mice died at a late stage of embryonic development or shortly after birth. Both TH mRNA and enzyme activity were lacking in the homozygous mutants, which thus explained the severe depletion of catecholamines. These changes, however, did not affect gross morphological development of the cells that normally express high catecholamine levels. Analysis of electrocardiograms of surviving newborn mutants showed bradycardia, suggesting an alteration of cardiac functions in the homozygous mice that may lead to the lethality of this mutation. In addition, transfer of a human TH transgene into the homozygous mice corrected the mutant phenotype, showing recovery of TH activity by expression of the human enzyme. These results indicate that TH is essential for survival of the animals during the late gestational development and after birth.
Animals↗
Requirement of AP-1 for ceramide-induced apoptosis in human leukemia HL-60 cells.
Ceramide has emerged as a novel lipid mediator in cell proliferation, differentiation, and apoptosis. In this work, we demonstrate that the levels of c-jun mRNA, c-Jun protein, and DNA binding activity of a nuclear transcription factor AP-1 to 12-o-tetradecanoylphorbol 13-acetate responsive elements all increased following treatment with the cell-permeable ceramide, N-acetylsphingosine in human leukemia HL-60 cells. N-Acetylsphingosine (1-10 microM) increased the levels of c-jun mRNA in a dose-dependent manner, and maximal expression was achieved 1 h after treatment. Increase of c-jun expression treated with 5 microM N-acetyldihydrosphingosine, which could not induce apoptosis, was one third of that with 5 microM N-acetylsphingosine. Ceramide-induced growth inhibition and DNA fragmentation were both prevented by treatment with curcumin, 1,7-bis[4-hydroxy-3-methoxy-phenyl]-1,6-heptadiene-3,5-dione (an inhibitor of AP-1 activation), or antisense oligonucleotides for c-jun. These results suggest that the transcription factor AP-1 is critical for apoptosis in HL-60 cells and that an intracellular sphingolipid mediator, ceramide, modulates a signal transduction inducing apoptosis through AP-1 activation.
Apoptosis↗
Immunoassay for the quantification of intracellular multi-ubiquitin chains.
A sandwich ELISA has been developed to measure intracellular levels of multi-ubiquitin chains. The mixture of multi-ubiquitin chains, prepared in vitro by incubation of ubiquitin (plus 125I-ubiquitin) and lysozyme with ubiquitin-ligating enzymes and ATP, was partially purified and established as a standard named the multi-ubiquitin-chain reference preparation 1 (MUCRP1). The concentration of MUCRP1 was calculated from the recovered radioactivity of 125I-ubiquitin. All measurements by the ELISA were expressed in terms of MUCRP1. The ELISA showed good sensitivity (98 pg/ml), precision (intra-assays < 6%) and reproducibility (interassay < 9%). In addition, there was no substantial cross-reaction with mono-, di- and tri-ubiquitin, or mono-ubiquitinated and di-ubiquitinated lysozyme in the ELISA, and large multi-ubiquitin chains (n > approximately 6) may be fully reactive. These results combined with excellent results in the recovery and dilution tests guarantee accurate measurement of multi-ubiquitin chains in cell extracts prepared with a lysis buffer (water soluble) or the buffer supplemented 8 M urea (urea soluble). The level of the water-soluble multi-ubiquitin chains in reticulocytes was lower than that of erythrocytes, but the urea-soluble chain level was higher in the reticulocytes. Heat-shock treatment of HeLa cells increased the urea-soluble multi-ubiquitin chains. These data indicate that this ELISA provides a useful and reliable approach to the study of intracellular multi-ubiquitin-conjugate turnover.
Animals↗
Structural studies on a cell wall polysaccharide from Bifidobacterium longum YIT4028.
The major fraction of rhamnogalactan was isolated from the cell wall of Bifidobacterium longum YIT4028 by treatment with N-acetylmuramidase. This polysaccharide was composed of rhamnose and galactose in a molar ratio of about 2:3. The 13C NMR spectrum indicated that it contained a pentasaccharides repeating unit. This observation, and the results of Smith degradation, partial acid hydrolysis and methylation analysis led to the conclusion that its structure is [formula: see text]
Bifidobacterium↗
Band theory for ground-state properties and excitation spectra of perovskite LaMO3 (M=Mn, Fe, Co, Ni).
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Journal Article↗
Phosphorylation of proteasome substrate by a protein kinase associated with the 26 S proteasome is linked to the ATP-dependent proteolysis of the 26 S proteasome.
A protein kinase phosphorylating the 45-kDa proteasome subunit was co-purified with the 26 S proteasome from the porcine heart. This kinase appears to be associated with the 26 S proteasome, since the kinase activity was co-eluted with the 26 S proteasome on Superose 6 FPLC and immunoprecipitated with anti-20 S proteasome antibody. This kinase also phosphorylated the casein. Furthermore, the phosphorylated casein was more efficiently hydrolyzed by the 26 S proteasome than the dephosphorylated casein without ATP. Inhibition patterns of kinase inhibitors against the 45 kDa subunit and casein were well in accord with the inhibition pattern against the ATP-dependent proteolysis of the 26 S proteasome, suggesting that the phosphorylation of casein by a protein kinase associated with the 26 S proteasome is linked to the ATP-dependent proteolysis of the 26 S proteasome.
Adenosine Triphosphate↗
N-acetylglucosaminidase inhibitor isolated from the vitelline coat of ascidian eggs is a candidate sperm receptor.
An inhibitor against the egg beta-D-N-acetylglucosaminidase (GlcNAcase) was purified from the vitelline coat of eggs of the ascidian, Halocynthia roretzi. The purified inhibitor gave a single band with an apparent molecular mass of 70 kDa on SDS-PAGE under non-reducing conditions. The GlcNAcase inhibitor potently inhibited the ascidian egg GlcNAcase activity, and also substantially inhibited the GlcNAcase activity in the ascidian sperm extract, although to lesser extent. In contrast, it showed little inhibitory effect on the activity of GlcNAcase from Jack beans. This inhibitor was found to block the binding of sperm to the vitelline coat of the eggs in a concentration-dependent manner. These results strongly suggest that the GlcNAcase inhibitor isolated from the vitelline coat functions in the binding of sperm to the egg coat, as a possible sperm receptor.
Acetylglucosaminidase↗
High expression of c-kit in K562YO cells due to the prolonged half-life of its mRNA: the effects of modification with serine/threonine kinase signals.
We previously reported that the K562 cell line K562YO expressed a high level of the c-kit gene. In this study, we analyzed the mechanism of this expression and investigated the effects of the serine/threonine kinases such as protein kinase C (PKC) and cyclic adenosine 3',5'-monophosphate (cAMP)-dependent kinase (PKA) on it. The half-life of the c-kit mRNA in K562YO cells was greater than 10 hours, compared with 2 hours in the original K562 cells, which expressed a very low level of c-kit mRNA. This prolonged half-life can contribute to the high level of c-kit expression in K562YO cells. Cycloheximide (CHX), a protein synthesis inhibitor, caused increases in c-kit mRNA levels in K562YO cells. 12-O-tetradecanoylphorbol-13-acetate (TPA), by which PKC was activated at first and downregulated in a late phase, gradually decreased c-kit mRNA in K562YO cells until 9 hours and then returned to the control level 24 hours after treatment. TPA also rapidly decreased c-kit protein level on the membranes. In whole cells, c-kit protein was also decreased 6 hours after incubation with TPA. Calphostin C, a light-dependent PKC inhibitor, decreased c-kit mRNA levels within 30 minutes in a light-dependent manner. It also decreased c-kit protein in whole cells 2 hours after the addition. However, it increased the amount of c-kit protein on the cell surfaces. Dibutyryl cyclic AMP (dbc-AMP) increased c-kit mRNA as well as c-kit protein on membranes and in whole cells. Run-on transcriptional assay suggested that the agent (dbc-AMP) enhanced the transcription rate of the gene. These results suggest that c-kit protein on the membranes is downregulated by PKC activation and upregulated by PKC inhibition. In the whole cell lysate, c-kit proteins are decreased by PKC inhibition through downregulation of mRNA. On the other hand, the elevation of an intracellular cAMP level causes upregulation of both the mRNA and c-kit protein on membranes and in whole cells through enhanced transcription. Thus, c-kit gene expression is apparently modulated by PKC and PKA.
Bucladesine↗
Immunotoxin-mediated conditional disruption of specific neurons in transgenic mice.
We have developed a transgenic approach, termed immunotoxin-mediated cell targeting (IMCT), to ablate conditionally selective neurons in the brain with the cytotoxic activity of immunotoxins. Transgenic mice were created that express the human interleukin 2 receptor alpha subunit (IL-2R alpha) under the control of the dopamine beta-hydroxylase (DBH) gene promoter. The animals were treated intracerebroventricularly with a recombinant immunotoxin, anti-Tac(Fv)-PE40, which selectively kills animal cells bearing human IL-2R alpha. The immunotoxin caused a characteristic behavioral abnormality only in the transgenic mice. This was accompanied by a dramatic loss of DBH-containing neurons and a significant decrease in DBH activity and norepinephrine levels in various regions of the brain. IMCT should provide a general technique to create animal models of human neurodegenerative disorders by targeting neurons or other cell types.
ADP Ribose Transferases↗
Efficient production of anti-(hepatitis B virus) antibodies and their neutralizing activity in chimpanzees.
For industrial production of human monoclonal antibodies (hmAb) against hepatitis B virus surface antigen (HBsAg), we scaled-up a short-term perfusion culture in serum-free medium, which was chosen as the most suitable culture method, to a 50-1 fermentor equipped with a rotating shear filter. Using hydrophobic chromatography as the initial step of hmAb purification, the mAb HBW4, HBW6 and W471 were isolated in good quality from the respective culture broths in yields of approximately 75%. Each of the three purified hmAb alone, and a cocktail of the three, protected chimpanzees against HB virus, when injected intravenously 3 h after viral challenge, as long as the serum antibody levels were significant. A pharmacokinetic study using cynomolgus monkeys demonstrated that the hmAb have a long plasma half-life and bioavailability of approximately 76% upon intramuscular injection in primates. Thus, anti-HBsAg hmAb produced by an industrial process are expected to be successfully used in clinical fields.
Animals↗
Distribution of galanin-immunoreactive nerve fibers in the carotid labyrinth of the bullfrog, Rana catesbeiana: Comparison with substance P-immunoreactive fibers.
Immunoreactivity of galanin (GAL) was detected in the nerve fibers distributed within the intervascular stroma of the bullfrog carotid labyrinth. GAL-immunoreactive fibers are numerous, and some are close to the sinusoidal plexus. Most GAL fibers appear as thin processes with some varicosities. A combination of indirect double immunofluorescence labelling and image processing clearly demonstrated that the distribution pattern of GAL fibers is different from that of SP fibers. This indicates that GAL and SP do not coexist in the same nerve fibers. The role of GAL fibers may be different from that of previously reported neuropeptides (substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide, neuropeptide Y, and others) as a neuromodulator in controlling vascular tone of the labyrinth.
Animals↗
Dysphagia caused by an anterior cervical osteophyte: case report.
Cervical spondylosis and ankylosing hyperostosis of the cervical vertebrae are commonly asymptomatic. Dysphagia caused by cervical osteophyte formation is rare. We report a case of spondylotic dysphagia with striking radiographic findings. A massive anterior cervical hyperostosis was resected via the anterior cervical approach with excellent relief of dysphagia.
Cervical Vertebrae↗
Erythroid differentiation and growth inhibition of K562 cells by 2',5'-dideoxyadenosine: synergism with interferon-alpha.
We found that 2',5'-dideoxyadenosine (DDA), a P-site specific adenylate cyclase inhibitor, inhibited the growth of K562 cells and caused them to become benzidine positive. The continuous exposure of cells to DDA was needed to recruit cells for growth inhibition and differentiation. Fetal calf or human sera were also necessary for DDA to induce differentiation. DDA at a concentration of 1.5 mM with serum induced 98% of the cells to produce hemoglobin and inhibited their growth to 15% of that of the control. An increase of epsilon-globin mRNA and a decrease of c-myc and c-myb mRNA occurred only during differentiation in the presence of fetal calf serum (FCS). An incubation with DDA and interferon-alpha (IFN-alpha) or hemin synergistically induced more benzidine-positive cells than in the presence of DDA alone, although IFN-alpha did not trigger differentiation by itself. The erythroid differentiation and growth inhibition were, however, not related to a decreased intracellular cyclic AMP (cAMP) concentration induced by DDA. The simultaneous incubation with dibutyryl cyclic AMP (dbc-AMP) and DDA enhanced the effects of DDA. Adenine, a possible metabolite of DDA digestion by purine nucleoside phosphorylase (PNP), also induced erythroid differentiation in K562 cells. However, it did not act synergistically with IFN-alpha.
Adenine↗