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Biomedical subjects

S Arai

Publications and source records attributed to S Arai.

At least 163 records · Page 9Linked to original sources
PubMed1997

[Open heart surgery without homologous blood transfusion in elderly patients].

Preoperative autologous blood donation has been widely accepted to perform surgery in orthopedics, gynecology and cardiac surgery. In elderly patients, however, it has been supposed that most of these patients have anemic tendency before predonation as well as poor response to erythropoietic stimuli, so that preoperative blood deposit is limited to apply them. In order to reduce homologous blood transfusion in open-heart surgery, preoperative blood deposit, combined with erythropoietin administration and intraoperative blood salvage, have been routinely used even for the elderly patients in our hospital since 1989. In present study, we verified above concepts and obtained the results that demonstrated little differences in the blood reproducing ability, the rate of predonation, and the recovery after the operation, between the elderly and the younger. We concluded that autologous blood transfusion combining preoperative deposit with intraoperative blood salvage was the efficient and safe method even in the elderly patients.

Adolescent↗
PubMed1997

[A successful retraining of the left ventricle with a left ventricular assist device (bio-medicus) after the arterial switch operation].

We experienced the case of a patient with d-TGA, small VSD who underwent arterial switch operation (ASO) at the age of 8 weeks. In pre-operative UCG, the LV posterior wall thickness was only 3.0 mm. LV systolic pressure had dropped to 29 mmHg at the time of operation. After arterial switch and VSD closure, myocardial contractility and coronary perfusion were good without any ST-T changes, however, the patient could not be weaned from cardiopulmonary bypass. Left ventricular assist device (LVAD) was then applied and LV training was performed with appropriate pre and after-load. On the 4th operative day, the patient was successfully weaned from LVAD. Training of the left ventricle with LVAD will be a useful life-saving method in the case of left ventricular failure after arterial switch operation.

Cardiac Surgical Procedures↗
PubMed1997

[Successful TSH suppression therapy with triiodothyronine in a patient with pulmonary metastases from differentiated thyroid carcinoma in the absence of 131I uptake].

A 28-year-old woman was referred to us to undergo 131I therapy who had multiple pulmonary metastases from papillary thyroid carcinoma after total thyroidectomy. There was no increased accumulation of a tracer in the pulmonary metastatic foci on whole-body scanning using a 111 MBq diagnostic dose of 131I. However, the pulmonary metastases were gradually decreased in size, and then clearly reduced 8 months after the start of TSH suppression therapy, which was maintained by T3 instead of T4 to bring down the serum TSH level below 0.1 microU/ml. Reduction rates of the foci were 33-76% on chest X-ray. The reduction was confirmed and no new lesions were found on the serial CT scans. Serum thyroglobulin level was lowered 80 to 25 ng/ml by this suppression therapy and progression of disease was not observed under a 54 months' T3 treatment. Thus, TSH suppression therapy might improve survival of patients with differentiated thyroid cancer.

Adult↗
PubMed1996

Inducible nitric oxide synthase following hypoxia in rat cultured glial cells.

Nitric oxide (NO) produced by inducible nitric oxide (iNOS) exerts inhibitory and cytotoxic effects on various cells including neuronal cells. In the present study, we examined the ability of rat glial cells to produce NO following hypoxia/reoxygenation in vitro by measuring nitrite. The levels of nitrite produced in the cultured media of glial cells significantly increased after 12-h hypoxia but not after 0- and 6-h hypoxia. The NOS inhibitor, NG-monomethyl-L-arginine, decreased hypoxia-induced nitrite formation. In glial cells after hypoxia/reoxygenation, the iNOS and mRNA and protein expressions were detected by reverse-transcription polymerase chain reaction and by immunocytochemical analysis, respectively. The present study provides the first evidence that hypoxia induces NO production from glial cells. This hypoxia-induced, glial cell-derived NO may play a critical role in the pathogenesis of cerebral ischemia in vivo.

Animals↗
PubMed1996

Soyacystatin, a novel cysteine proteinase inhibitor in soybean, is distinct in protein structure and gene organization from other cystatins of animal and plant origin.

Cystatins, cysteine proteinase inhibitors, deserve note because of their regulatory and protective functions in plant tissues. We isolated both genomic DNA and cDNA clones from soybean that encode a cystatin consisting of 245 amino acid residues (soyacystatin). It is, while basically similar in sequence to known cystatins that are generally in the range of 12-15 kDa, characterized by having extremely large extension sequences in both its amino and carboxyl termini. The genomic DNA encoding soyacystatin is also unique in that it consists of four exons with three introns in its coding regions. The mRNA for soyacystatin is distinctly expressed in soybean seeds 2 weeks after flowering. Soyacystatin purified from mature soybean seeds had a molecular mass of about 26 kDa on SDS/PAGE which suggests that it contains the extension sequences. Papain-inhibition experiments demonstrate that this endogenous soyacystatin has almost the same inhibitory activity as that of its deletion mutant (102 amino acid residues) recombinantly produced by truncation of the amino and carboxyl terminal extensions, indicating that the occurrence of the extensions does not affect the cystatin activity. Immunohistochemical experiments reveal that soyacystatin is expressed nearly uniformly in the cotyledons. These results also suggest the possible occurrence of a cysteine proteinase as the target enzyme of soyacystatin.

Amino Acid Sequence↗
PubMed1996

Identification of Bruton's tyrosine kinase (Btk) gene mutations and characterization of the derived proteins in 35 X-linked agammaglobulinemia families: a nationwide study of Btk deficiency in Japan.

Deficiencies of Bruton's tyrosine kinase (Btk) have been implicated in the pathogenesis of human X-linked agammaglobulinemia (XLA). The distinctive phenotype observed in B-cell deficiency indicates the crucial role of Btk in B-cell development. This report describes a nationwide study of Btk deficiency in Japan, covering 51 XLA patients (35 independent families). Along with the identification of mutations, the resulting protein products were characterized by an in vitro kinase assay and a Western blot analysis. Thirty-one of the families were found to have mutations in the coding region of Btk. Although mutations were not found in the cDNA of 4 families, the Btk transcripts of these patients were greatly reduced. The identification of several novel missense mutations, in combination with the result of other studies, clarified the presence of two (missense) mutation hot spots, one in the SH1 and the other in the PH domain. The absence of kinase activity seen in 32 of the families underscored the importance of Btk protein analysis as a diagnostic indicator of XLA. The protein analysis also clarified the different effects of missense mutations on kinase activity and protein stability.

Adolescent↗
PubMed1996

Inhibition of basophil histamine release by a haptenic peptide mixture prepared by chymotryptic hydrolysis of wheat flour.

For application to the treatment of wheat-sensitive allergy, we developed a practical method for producing a haptenic peptide mixture, and evaluated its haptenic properties. Wheat flour was hydrolyzed with chymotrypsin to obtain a hydrolysate, and the diffusible fraction from the hydrolysate was subjected to gel-filtration. The resulting oligopeptide fraction could bind to wheat-specific IgE antibodies in the serum of patients allergic to wheat. Since this peptide mixture did not induce histamine release from basophils in these patients, it was concluded that the peptide mixture was composed of monovalent haptens. Histamine release from antigenstimulated basophils was almost completely inhibited when the basophils were preincubated with the haptenic peptide mixture. These results suggest that this haptenic peptide mixture can regulate the allergenic reaction in an epitope-specific manner.

Basophils↗
PubMed1996

Induction of brain-derived neurotrophic factor (BDNF) and the receptor trk B mRNA following middle cerebral artery occlusion in rat.

Middle cerebral artery (MCA) occlusion in halothane-anesthetized rats induced brain-derived neurotrophic factor (BDNF) and the receptor, trk B mRNA, in brain. In situ hybridization studies showed that BDNF and trk B mRNAs were induced in a widespread region of the ipsilateral cortex outside the infarct at 4 h following MCA occlusion. They were also induced in the bilateral hippocampi which are remote from the ischemic MCA region. These data show that changes in neurotrophic factor and receptor gene expressions can occur in the areas outside the infarct which could survive.

Animals↗
PubMed1996

Radioresistant DNA synthesis in fibroblast cell lines derived from LEC strain rats.

Immortalized cell lines from LEC strain (LEC) rats by SV40 large T antigen were more sensitive to X-irradiation than the cell lines from WKAH strain (WKAH) rats. The dose-response curves for inhibition of DNA synthesis in WKAH-derived cells showed a steep decline at low doses and a shallow decline at high doses. On the contrary, the dose-response curves for LEC-derived cell lines showed no steep component; they were almost identical to the shallow component of the curves for WKAH-derived cells.

Animals↗
PubMed1996

Involvement of two distinct killing mechanisms in bystander target cell lysis induced by a cytotoxic T lymphocyte clone.

Cytotoxic T lymphocyte (CTL) can lyse target cells by mainly two different mechanisms including granule exocytosis- and Fas-based cytotoxicity. In addition, CTL also lyse bystander target cells. In this study, we examined whether these two different killing mechanisms also cause bystander target cell lysis. EL-4 cells, representing bystander target cells, were incubated with CD8+ CTL clone B7B7 and antigen-treated P815 cells. EGTA-MgCl2 inhibited bystander lysis and reduced the release of BLT esterase. In addition, lysis of Fas-negative bystander cells (thymocytes from C57BL/6J-lpr/lpr not expressing Fas antigen) was also detected. CTL preactivated with antigen-treated P815 cells maintained a killing activity on bystander cells in the presence of cycloheximide (CHX). Furthermore, the presence of anti-Fas mAb inhibited the lysis of EL-4 cells by CTL stimulated with anti-TCR mAb. Thus, our results suggest that granule exocytosis- and Fas-mediated signal pathways cause the lysis of bystander target cells.

Animals↗
PubMed1996

A water channel closely related to rat brain aquaporin 4 is expressed in acid- and pepsinogen-secretory cells of human stomach.

We isolated a cDNA clone encoding a water channel protein, aquaporin ( AQP), from human stomach. The encoded protein consisted of 323 amino acid residues, containing six putative transmembrane domains. The protein was designated human aquaporin 4 (hAQP4) because of its 94% sequence similarity to rat brain AQP4. Expression of hAQP4 cRNA in Xenopus oocytes resulted in a significant increase in osmotic water permeability, indicating that this protein functions as a water channel. Northern blot analysis demonstrated a strong signal of hAQP4 mRNA in brain, lung, and skeletal muscle as well as in stomach. Immunohistochemical experiments with human stomach tissues showed that hAQP4 as a protein is expressed mainly in cells located in the glandular portion of the fundic mucosa. These include chief cells which secrete pepsinogen and parietal cells which secrete hydrochloric acid. These results strongly indicate that hAQP4 is a principal factor involved in the osmotic regulation of pepsinogen and acid secretion in the stomach.

Amino Acid Sequence↗
PubMed1996

A major wheat allergen has a Gln-Gln-Gln-Pro-Pro motif identified as an IgE-binding epitope.

The minimum primary structure of the IgE-binding epitope in wheat gluten was determined as Gln-Gln-Gln-Pro-Pro. The N-terminal glutamine and the two proline residues were essential for epitopic function. The occurrence of the second glutamine residue and acetylation of the N-terminal amino group were found to exert some auxiliary functions, whereas only a lesser contribution was expected for the third glutamine residue. It has also been confirmed that acetyl-Gln-Gln-Gln-Pro-Pro bound to wheat-specific IgE antibodies in the sera of patients allergic to wheat, although it did not induce histamine release from the basophils of these patients. Taken together, we concluded that the Gln-Gln-Gln-Pro-Pro motif constituted an IgE-binding rather than immunogenic epitope and also that acetyl-Gln-Gln-Gln-Pro-Pro might act as a hapten capable of binding to specific IgE molecules. The possibility exists that this peptide will have practical application to therapy for or prevention of wheat-sensitive allergy.

Allergens↗
PubMed1996

Isolation of a genomic DNA fragment having negative vitamin D response element.

The vitamin D receptor (VDR) binds to the vitamin D response element (VDRE) in the promoter region of target genes and acts as a ligand-dependent transcriptional regulator. In order to identify novel VDREs and new genes that are regulated by the active form of vitamin D [1,25-(OH)2D3], rat genomic DNA fragments bound by VDR were isolated. One of these fragments, designated as VBF5 was transcribed and the transcript was down-regulated by 1,25-(OH)2D3. These data strongly indicate that VBF5 may contain a VDRE regulating negatively an unidentified gene expression.

Animals↗
PubMed1996

Molecular cloning and functional expression of the alpha1A-adrenoceptor of Medaka fish, Oryzias latipes.

A genomic DNA encoding a subtype adrenoceptor (AR) was cloned from Medaka fish, Oryzias latipes, using an oligonucleotide probe corresponding to the consensus sequence of mammalian alpha-AR and beta-AR. The gene spans at least 9kbp, and the coding region consists of two exons split by an intron of 7.2 kbp located at the same position as those of mammalian alpha1B-AR genes. The gene encodes 470 amino acid residues, the sequence of which shows the highest similarity to that of mammalian alpha1A-AR (61%) and significant but lower similarities to other alpha-AR and beta-AR proteins (31-45%), indicating that the gene encodes a Medaka homolog of alpha1A-AR. To characterize the encoded protein, the mRNA was synthesized in vitro and injected into Xenopus oocytes. As a result, the oocytes responded to 100 nM epinephrine evoking a Ca2 + -dependent C1- current in the order of microamperes, which was not observed for oocytes injected with water alone. The response was reversibly inhibited by an alpha1-selective antagonist, WB4101 (2-[2,6-dimethoxphenoxyethyl]aminomethyl)-1,4-benzodioxane). Similar experiments using several adrenergic agonists revealed that Medaka alpha1A-AR responds to the following agonists in the order: epinephrine > or = (-)norepinephrine > oxymetazoline > or = methoxamine, which is similar to the responses of rat alpha1A receptor expressed in COS cells. The results indicate that fish contains adrenoceptor systems similar to those of mammals in terms of primary structure and pharmacological properties.

Amino Acid Sequence↗
PubMed1996

Transgenic rice established to express corn cystatin exhibits strong inhibitory activity against insect gut proteinases.

Corn cystatin (CC), a phytocystatin, shows a wide inhibitory spectrum against various cysteine proteinases. We produced transgenic rice plants by introducing CC cDNA under CaMV 35S promoter as a first step to obtain a rice plant with insecticidal activity. This attempt was based on the observation that many insect pests, especially Coleoptera, have cysteine proteinases, probably digestive enzymes, and also that oryzacystatin, an intrinsic rice cystatin, shows a narrow inhibition spectrum and is present in ordinary rice seeds in insufficient amounts to inhibit the cysteine proteinases of rice insect pests. The transgenic rice plants generated contained high levels of CC mRNA and CC protein in both seeds and leaves, the CC protein content of the seed reaching ca. 2% of the total heat soluble protein. We also recovered CC activity from seeds and found that the CC fraction efficiently inhibited both papain and cathepsin H, whereas the corresponding fraction from non-transformed rice seeds showed much lower or undetectable inhibitory activities against these cysteine proteinases. Furthermore, CC prepared from transgenic rice plants showed potent inhibitory activity against proteinases that occur in the gut of the insect pest, Sitophilus zeamais.

Animals↗
PubMed1996

A mouse model for cerebral babesiosis.

Clinical symptoms and pathology observed in the cattle infected with Babesia bovis are quite similar to those of human cerebral malaria. Mechanisms involved in the pathogenesis of cerebral babesiosis, however, are still poorly understood because of the lack of a suitable experimental animal model. In this report, Masayoshi Tsuji and his colleagues describe B. bovis infection in severe combined immunodeficiency (SCID) mice, whose circulating red blood cells (RBCs) have been substituted with bovine RBCs (Bo-RBC-SCID mice). The infected mice not only develop a substantial level of parasitemia, but also show nerve symptoms and pathology similar to those observed in infected cattle.

Journal Article↗
PubMed1996

GUST27 and closely related G-protein-coupled receptors are localized in taste buds together with Gi-protein alpha-subunit.

Gustatory, like olfactory signalling is probably mediated by seven-transmembrane receptors and coupling GTP-binding proteins (G proteins). We investigated the expression of a subset of these receptors and the Gi protein alpha-subunit by using their specific antibodies. Based on our previous finding that the mRNA for GUST27, one of these receptors, is expressed in rat lingual epithelia, we first prepared an antibody to the synthetic nonapeptide, H-Ser-Tyr-Ser-Gln-Ile-Ala-Ser-Ser-Leu-OH, which corresponds to the third intracellular domain of GUST27 and also to those of a subset of related receptors whose occurrence can be predicted by PCR. Immunohistochemical studies with rat circumvallate papillae indicated that the anti-GUST27 antibody reacted with many of the taste buds examined, with strong signals appearing in particular taste cells. We then carried out a similar immunohistochemical experiment with an antibody to the Gi protein alpha-subunit and found that this subunit is also expressed in taste buds as demonstrated in the case of gustducin and transducin. Taken together, these results strongly suggest that GUST27 and closely related receptors, as well as Gi alpha proteins, are involved in intracellular taste signal transduction.

Amino Acid Sequence↗