Search PubMed⌕ Search

Biomedical subjects

Y Asada

Publications and source records attributed to Y Asada.

At least 91 records · Page 5Linked to original sources
PubMed1999

Nitric oxide is the predominant mediator for neurogenic vasodilation in porcine pial veins.

The innervation pattern and the vasomotor response of the potential transmitters in the porcine pial veins were investigated morphologically and pharmacologically. The porcine pial veins were more densely innervated by vasoactive intestinal polypeptide (VIP)- and neuropeptide Y-immunoreactive (I) fibers than were calcitonin gene-related peptide (CGRP)-I, choline acetyltransferase-I, Substance P (SP)-I, and NADPH diaphorase fibers. Serotonin (5-HT)-I fibers, which were not detected in normal control pial veins, were observed in isolated pial veins after incubation with 5-HT (1 microM). 5-HT-I fibers, however, were not observed when incubation with 5-HT was performed in the presence of guanethidine (1 microM), suggesting that 5-HT was taken up into the sympathetic nerves. In vitro tissue bath studies demonstrated that porcine pial veins in the presence of active muscle tone relaxed on applications of exogenous 5-HT, CGRP, SP, VIP, and sodium nitroprusside, whereas exogenous norepinephrine and neuropeptide Y induced only constrictions. Transmural nerve stimulation (TNS) did not elicit any response in pial veins in the absence of active muscle tone. However, in the presence of active muscle tone, pial veins relaxed exclusively on TNS. This tetrodotoxin-sensitive relaxation was not affected by receptor antagonists for VIP, CGRP, 5-HT, or SP but was blocked by L-glutamine (1 mM) and abolished by Nomega-nitro-L-arginine (10 microM) and Nomega-nitro-L-arginine methyl ester (10 microM). The inhibition by L-glutamine, Nomega-nitro-L-arginine, and Nomega-nitro-L-arginine methyl ester was reversed by L-arginine and L-citrulline but not by their D-enantiomers. These results demonstrate that the vasomotor effect of all potential transmitters except 5-HT in the pial veins examined resembles that in cerebral arteries. Although porcine pial veins receive vasodilator and constrictor nerves, a lack of constriction on TNS suggests that the dilator nerves that release nitric oxide may play a predominant role in regulating porcine pial venous tone.

Animals↗
PubMed1999

[Histopathology of thrombotic vascular diseases].

Three principal factors predispose to thrombus formation (Virchow's triad): (1) endothelial injury, (2) stasis or turbulence of blood flow, and (3) blood hypercoagulability. Endothelial denudation is the most important factor, especially in the development of arterial thrombus. Arterial thrombi are frequently occlusive, and the most common sites are coronary, cerebral, and femoral arteries. The thrombi induce severe ischemia or infarction of the heart, brain, and lower extremities. The thrombi are usually superimposed on an atherosclerotic plaque. Plaque rupture or erosion is considered to be the trigger of acute thrombus formation. While venous thrombi are invariably occlusive, and commonly affect the lower extremities. Static blood flow, phlebitis, and genetic and acquired hypercoagulability often contribute to venous thrombosis.

Endothelium, Vascular↗
PubMed1999

[Smooth muscle myosin of SM1 and SM2 isoforms expressing human neuroblastoma cell line of MP-N-MS].

Human neuroblastoma (NB) cell lines have at least three morphological appearance of neuroblastic (N-type), substrate-adhessive (S-type) and intermediate(I) cells. Our previous study revealed S-type cells expressed alpha-smooth muscle actin, desmin and/or basic-calponin, indicating the plausible smooth muscle cell characteristics of S-type cells. In this study, a new human NB cell line, MP-N-MS, was established from bone marrow metastasis of a one year and six-month old girl with advanced NB, originating from right adrenal gland. Morphology of this cell line is composed of S-type cells. MP-N-MS was identified as a NB cell line by surface membrane antigen analysis and MYCN gene amplification. EWS-FLI1 and EWS-ERG chimeric products, observed in Ewing family tumors, were not detected by RT-PCR (reverse transcriptase-polymerase chain reaction). In cytoskeletal protein analysis, alpha-smooth muscle actin and basic calponin of smooth muscle cell markers were detected. Furthermore, smooth myosin of SM1 isoform was identified in MP-N-MS cell line by immunofluorescence, Western blot and RT-PCR, whereas smooth myosin of SM2 was detected by RT-PCR. MP-N-MS is the first cell line, showing SM1 and SM2 isoforms. The presence of smooth muscle myosin of SM1 and SM2 isoforms in MP-N-MS demonstrated the mature smooth muscle phenotype of this NB cell line, and the ability of NB cells to differentiate into smooth muscle cell.

Cell Differentiation↗
PubMed1999

Rotatory motion of a cemented acetabular component caused by aseptic loosening and dissociation of the polyethylene liner: a case report.

A 63-year-old woman without rheumatoid arthritis who had undergone cemented total hip arthroplasty developed coxalgia 1 year later. Radiography showed a clear zone at the cement-implant interface and rotatory motion of the acetabular component, so revision surgery was performed 4.5 years after the first operation. Aseptic loosening was noted and 7 spacers outside the acetabular component were broken and buried under the cement mantle. We consider that the rotatory motion may be caused by circumferential loosening of the acetabular component stemming from incomplete implant fixation and also dissociation of the ultra-high-molecular weight polyethylene (UHMWPE) liner from the metal base plate.

Acetabulum↗
PubMed1998

Redox properties of an H-subunit-depleted photosynthetic reaction center from Rhodopseudomonas viridis.

Recently, we reported that a H-subunit-depleted photosynthetic reaction center (RC-H) was purified from purple nonsulfer photosynthetic bacterium Rhodopseudomonas viridis (Rps. viridis) using a strong detergent sodium alkyl ether sulfate. We compared the redox properties of a native photosynthetic reaction center (RC) and RC-H of Rps. viridis. In RC-H prepared by our method, secondary quinone (QB) was removed while primary quinone (QA) was retained. Absorption spectrum of RC-H was similar to that of RC. After reconstitution of ubiquinone 10 into QB sites, RC-H showed electron transfer activity that was the same as that for native RC. This is the first report about the redox properties of RC-H of Rps. viridis.

Electron Transport↗
PubMed1998

Sodium alkyl ether sulfate preparative electrophoresis for the preparation of reaction centers without H-subunit from Rhodopseudomonas viridis.

Sodium alkyl ether sulfate (AES), an analog of sodium dodecyl sulfate (SDS) was used in polyacrylamide gel electrophoresis (PAGE) for the partial decomposition of the photosynthetic reaction center (RC) of Rhodopseudomonas viridis. Unlike SDS, AES did not completely dissociate RC into its subunits but selectively detached H-subunit from RC to give RC(-H) without losing the spectroscopic nature of RC. For the denaturation of RC(-H), AES was found to be as mild as 3-[3-cholamidopropyl)dimethylammonio]-l-propanesulfonate (CHAPS).

Electrophoresis, Polyacrylamide Gel↗
PubMed1998

Molecular breeding of the basidiomycete Coprinus cinereus strains with high lignin-decolorization and -degradation activities using novel heterologous protein expression vectors.

Two chromosome-integrating vectors, pLC1 and pLC2, were used. The former is the pUC19-based vector carrying the Lentinus edodes ras gene promoter and priA gene terminator, and the latter is the pBR322-based vector carrying the promoter and terminator of the priA gene. The manganese (II) peroxidase (MnP) cDNA (mnpc) derived from Pleurotus ostreatus was fused between the promoter and terminator of pLC1 and pLC2, yielding the recombinant plasmids pLC1-mnp and pLC2-mnp. These plasmids were introduced into protoplasts of the Coprinus cinereus trp1 strain with the C. cinereus TRP1-containing plasmid pCc1001 by co-transformation. Two Trp+ transformants for each plasmid, showing clearly higher lignin-decolorization activities, were obtained through introduction of pLC1-mnp and pLC2-mnp. Southern-blot analysis revealed that the four transformants all possess the mnpc sequence on their chromosomes. One Trp+ MnP+ transformant (named TF2-7), which was derived from the introduction of pLC2-mnp and carried the highest number of copies (approx. 10) of mnpc, showed remarkably high lignin-decolorization and -degradation activities; at the time of cultivation when only 35%-40% of the lignin was decolored and degraded by the control Trp+ transformant obtained by the introduction of pCc1001 alone, almost all of the lignin was decolored and degraded by TF2-7.

Blotting, Southern↗
PubMed1998

Adrenomedullin in the gastrointestinal tract. Distribution and gene expression in rat and augmented gastric adrenomedullin after fasting.

The aim of this study was to investigate the regional distribution, molecular forms, and gene expression of adrenomedullin in the rat gastrointestinal tract and to examine physiological changes in gastric adrenomedullin after 24-h fasting. The tissue concentration was measured by radioimmunoassay. The molecular forms were analyzed by high performance liquid chromatography. mRNA levels were quantified by Northern blotting and cells positive for adrenomedullin immunoreactivity were localized by immunohistochemistry. A high concentration of adrenomedullin was found in stomach, cecum, and colon (450-520 fmol/g wet tissue). Adrenomedullin immunoreactivity was also detected in duodenum, jejunum, and ileum (200-250 fmol/g wet tissue). Transcripts of the adrenomedullin gene were widely expressed throughout the gastrointestinal tract. The major form of adrenomedullin immunoreactivity in stomach and colon corresponded precisely with authentic adrenomedullin peptide. Adrenomedullin immunoreactive cells were present in the gastrointestinal endocrine system. The concentration and mRNA level of gastric adrenomedullin after fasting were significantly increased compared with findings in controls. Adrenomedullin is ubiquitous in the gastrointestinal tract, and may be produced by endocrine cells. The results suggest that adrenomedullin, through its potent vasodilating activity, may play some role, in the stomach including the regulation of the mucosal blood flow.

Adrenomedullin↗
PubMed1998

Expression of tissue factor in the rabbit aorta after balloon injury.

Tissue factor (TF) is a primary initiator of the extrinsic pathway of blood coagulation. Recently TF has been shown to be overexpressed in atherosclerotic lesions and it is thought to contribute to the thrombogenicity of the plaques. We studied TF expression in the media and the neointima of rabbit aortas at various intervals after balloon injury. TF protein was immunohistochemically detected in smooth muscle cells (SMCs) of the inner layer of the media at 2 h after injury and was subsequently detected in SMCs in the neointima, whereas no TF expression was detected in the uninjured aortas except for the adventitia. Immunohistochemical and immunoelectron microscopic studies revealed that TF-positive SMCs were of an immature or synthetic phenotype and TF protein was detected in the rough endoplasmic reticulum in SMCs. TF mRNA in the intima and media increased at 2 h after injury and returned to near baseline levels at 12-24 h, whereas TF activity also increased at 2 h and continued at similar levels over the next 72 h. TF mRNA and activity increased markedly at 2-8 weeks after injury. These data suggest that TF is rapidly induced in the medial SMCs and hereafter is constitutively expressed in the neointima. TF expressed in the neointima may contribute to hypercoagulable properties of injured arteries.

Animals↗
PubMed1998

Neural repair of the injured spinal cord by grafting: comparison between peripheral nerve segments and embryonic homologous structures as a conduit of CNS axons.

To study the differences between peripheral nerve (PN) and embryonic homologous CNS structures as a conduit for CNS axons, spinal cord segments in neonatal rats were removed at the mid-thoracic level and PN or embryonic spinal cord (ESC) segments were grafted into the vacancy. Neural connections across the graft were examined by the anterograde and retrograde tracing methods. Anterogradely labeled pyramidal tract fibers entered the PN segment meanderingly and were dispersed; most stopped at the caudal end of the graft. Although a small fraction of fibers re-entered the host spinal cord, they terminated near the graft-host interface without further extension. By contrast, similarly labeled fibers entering the ESC segments crossed the graft and extended further to reach the lumbar segments. The fibers were defasciculated in the graft but became fasciculated and oriented dorsally near the caudal end of the graft, and descended in the normal path. Consistent with these findings, the retrograde tracing study revealed that in animals with ESC segment grafts but not in those with PN segment grafts, many neurons in the upper brain structures were labeled with Fast Blue that was injected into the lumbar enlargement. The difference between the two kinds of graft as a conduit for CNS axons is likely to be due to differences in matching growing axons and their guidance cues through the graft-host interface.

Animals↗
PubMed1998

Antimicrobial flavonoids from Glycyrrhiza glabra hairy root cultures.

A new compound named licoagrodione was isolated from the hairy root cultures of Glycyrrhiza glabra (Fabaceae) together with five known prenylated flavonoids. The structure of licoagrodione has been elucidated on the basis of spectral evidence and it was found to have antimicrobial activity indicated by disc diffusion method.

Anti-Bacterial Agents↗
PubMed1998

Inhibitory effect of shofu-san, a Japanese kampo medicine, on neutrophil functions in vitro.

The effect of Shofu-san (TJ-22), an oral Japanese kampo medicine, on several inflammatory parameters of human neutrophils, including reactive oxygen species (ROS) generation, chemotaxis, and calcium concentration, [Ca2+]i in neutrophils was examined in vitro. In addition, ROS generated in a cell-free, xanthine-xanthine oxidase system was also assessed. The species investigated were superoxide radical anion (O2-), hydrogen peroxide (H2O2), and hydroxyl radical (OH.). TJ-22 significantly decreased neutrophil-generated O2-, H2O2 and OH. in a dose-dependent manner. The medicine also markedly inhibited neutrophil chemotaxis and [Ca2+]i in neutrophils. In addition, three kinds of ROS generated in the cell-free system was reduced in the presence of TJ-22. Our results indicate that TJ-22 may exert an anti-inflammatory action by inhibiting the neutrophil functions and scavenging ROS, leading to a reduction in oxidative tissue injury.

Calcium↗
PubMed1998

Distribution and expression of adrenomedullin in human gastrointestinal tissue.

Adrenomedullin (AM) is a biologically active peptide recently isolated from phaeochromocytoma. We report here the distribution and characterization of immunoreactive AM and gene expression of AM in human gastrointestinal tissue. Using a sensitive radioimmunoassay system for the peptide, immunoreactive human AM was detected in the stomach, duodenum, jejunum, ileum and colon. The AM concentration of these tissues was about 0.4-0.8 pmol/g wet tissue. Reverse phase and gel filtration high-performance liquid chromatographies showed that most of the immunoreactive AM in stomach and jejunum was identical to authentic human AM. By northern blot analysis, human AM mRNA was found to be expressed ubiquitously in the human gastrointestinal tissues. Furthermore, an immunohistochemical study revealed that immunoreactive AM cells were present in the gastrointestinal glands. These results suggest that AM may play some role as a gastrointestinal hormone.

Adrenomedullin↗
PubMed1998

The characterization of two Dictyostelium discoideum genes encoding ribosomal proteins with sequence similarity to rat L27a and L37a.

Two Dictyostelium discoideum ribosomal protein genes, denoted DdL27a and DdL37a, were isolated and sequenced. The DdL27a gene contained an open reading frame of 148 amino acids coding for a putative 16,407 Da protein, which was similar to rat L27a (82.6% similarity) and to ribosomal proteins from other species. The gene contained a 311-bp intron downstream from the ATG initiation codon with an A+T content of 75%. The DdL37a gene encoded a 9,999 Da protein consisting of 91 amino acids, which had high sequence similarity to rat, human, and chicken ribosomal protein L37a, and was interrupted by two introns of 254 bp and 75 bp in length. The DdL37a protein contained a typical zinc finger motif (Cys-X2-Cys-X14-Cys-X2-Cys), which may be involved in the interaction of proteins with nucleic acids. Genomic DNA blot analysis indicated that the DdL27a and DdL37a genes are present in single copies in the Dictyostelium haploid genome. The DdL27a and DdL37a mRNA were expressed maximally in growing amoebae, and their levels decreased during multicellular development, coordinately with the observed decrease in ribosome accumulation during later development.

Amino Acid Sequence↗
PubMed1998

Malignant mesothelioma of the pleura with a large tumor embolus in the left atrium: an autopsy case.

Malignant mesothelioma of the pleura often involves the heart but seldom invades the intracardiac cavity. We report a 78-year-old woman with right pleural mesothelioma who died of heart failure. An autopsy revealed that the tumor was present at the right pleura and invaded the right upper lobe of the lung and the mediastinum. The tumor also extended to the left atrium via the right pulmonary vein and filled the atrial cavity. Repeated transthoracic echocardiography failed to detect the tumor, but magnetic resonance imaging was useful for diagnosis.

Aged↗