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Biomedical subjects

C Sato

Publications and source records attributed to C Sato.

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

Expression of tumor necrosis factor-alpha gene during allograft rejection following rat liver transplantation.

BACKGROUND/AIMS: Tumor necrosis factor-alpha (TNF-alpha) is believed to play a role in hepatic allograft rejection. However, the specific cellular population responsible for TNF-alpha production during hepatic allograft rejection is not known. Circulating monocyte-macrophage cells are the primary systemic sources of TNF-alpha. In the liver, Kupffer cells are the main producers of TNF-alpha. In this study, we determined which cells are involved in TNF-alpha production during allograft rejection after orthotopic liver transplantation. METHODS: In situ hybridization was used to identify cells with TNF-alpha mRNA in the liver. Immunohistochemical staining with ED2 and ED3 was used to differentiate between cellular types (Kupffer cells versus infiltrating monocytes). To detect DNA fragmentation in liver cells, TdT-mediated biotin-dUTP nick-end labeling (TUNEL) was done. Studies were performed in the rat liver transplant model using rejecting (ACI to LEW) and non-rejecting (ACI to ACI) donor/recipient combinations. RESULTS: In the control group, cells with TNF-alpha mRNA were rarely observed. In the rejection group, TNF-alpha mRNA was observed in mononuclear cells that were mainly within the vessels of the portal region and occasionally in the sinusoids. The cells with the signals for TNF-alpha mRNA were ED2-negative and ED3-positive. DNA fragmentation was observed in hepatocytes as well as infiltrating mononuclear cells. CONCLUSIONS: The main producer of TNF-alpha may be infiltrating mononuclear cells such as monocyte-macrophage cells rather than Kupffer cells during allograft rejection after liver transplantation. Circulating monocyte-macrophages may play a role in the control of allograft rejection.

Animals↗
PubMed1999

Efficacy of endoscopic clipping for bleeding gastroduodenal ulcer: comparison with topical ethanol injection.

OBJECTIVE: Although endoscopic clipping is used widely for the treatment of bleeding gastroduodenal ulcers, clinical trials on its efficacy are scarce. The aim of this study is to assess the efficacy and safety of endoscopic clipping for hemostasis from bleeding gastroduodenal ulcers. METHODS: The present study was designed as a retrospective study using historical controls. One hundred consecutive patients with bleeding gastroduodenal ulcers were treated by endoscopic clipping. The preceding 91 consecutive patients treated by endoscopic pure ethanol injection were regarded as controls. Forty-nine of the clipping group and 41 of the ethanol group had lesions at sites difficult to perform endoscopic manipulation. Hemostatic rates, rebleeding rates, amounts of blood transfusion, and durations of hospital stay were analyzed. RESULTS: The hemostatic rate was 96% in both clipping and ethanol groups, whereas the rebleeding rate was lower (15% vs 29%, p = 0.023) in the former than the latter. In technically difficult cases, the hemostatic rate was comparable (96 vs 90%). CONCLUSION: In patients with bleeding gastroduodenal ulcers, endoscopic clipping may be a choice of therapy because of a low rebleeding rate compared with pure ethanol injection.

Ethanol↗
PubMed1999

Development of a new analytical method for the electrocardiogram using short-time first Fourier transforms.

To detect the minute electric potential inside the QRS complex, a new frequency domain method was designed using short-time First Fourier Transforms (SFFT) and high-frequency sampling (oversampling). SFFT improved the frequency resolution by oversampling that was applied to this analysis. The electric potential data of 15,000 points received weighted, running average processing and was subtracted from the original waveform to reduce the low-frequency component. The data in a segment of 160 ms, including QRS, was processed by frequency analysis with the SFFT computation routine. The ECG of healthy individuals was analyzed by this method and its usefulness evaluated. The processing waves of the X-axis, Y-axis, and Z-axis of a representative normal subject were formed into 3 groups of peak electric potential. SFFT enabled the detection of the structure inside the QRS complex without signal averaging, and is considered capable of evaluating the process of excitement inside the QRS complex in the various heart diseases.

Adult↗
PubMed1999

Cross desensitizations on contractions by P2-agonists of guinea pig ileum.

The present study was designed to clarify the characteristics of contractions of guinea pig ileal longitudinal muscles evoked by alpha,beta-methylene ATP as compared with those by other P2-agonists. alpha,beta-Methylene ATP, ADP-beta-S and 2-methylthio ATP as P2-agonists produced remarkable phasic contractions of the segment in a suramin-sensitive- and reactive blue-2-insensitive manner. However, ADP-beta-S and 2-methylthio ATP, unlike alpha,beta-methylene ATP, showed a biphasic contraction accompanied by a second sustained phase. Their second sustained contractions were notably suppressed by 30 microM reactive blue-2, probably being a component mediated by P2Y-purinoceptor. The phasic contractile response to alpha,beta-methylene ATP, but not ADP-beta-S and 2-methylthio ATP, was largely reduced by tetrodotoxin and atropine, indicating that the contraction is due to acetylcholine released from the cholinergic nerves. At 100 microM, alpha,beta-methylene ATP inhibited the phasic contractions caused by a low concentration of itself, but not those induced by ADP-beta-S and 2-methylthio ATP, presumably serving as a desensitizer of the P2-receptor. Although beta,gamma-methylene ATP per se showed little contraction, it prevented the contraction evoked by alpha,beta-methylene ATP, but not those by ADP-beta-S and 2-methylthio ATP. The contraction evoked by 100 microM 2-methylthio ATP was attenuated in the presence of ADP-beta-S at 10 and 30 microM. From separate cross-interactions between two groups of P2-agonists, there seems to be different subtypes of P2X-purinoceptors in the pre- and postsynapse in producing phasic contractions, but not sustained contractions that are mediated by, presumably, the P2Y-purinoceptor of the ileum.

Adenosine Diphosphate↗
PubMed1999

Bcl-2 protein expression and gut neurohormonal polypeptide/amine production in colorectal carcinomas and tumor-neighboring mucosa, which closely correlate to the occurrence of tumor.

To clarify whether advanced colorectal carcinomas and tumor-neighboring mucosa simultaneously produce both Bcl-2 protein and gut neurohormonal polypeptides and/or amines, and the interrelationship of these phenomenon, we studied retrospective analysis of Bcl-2 protein production and neuroendocrine characteristics in 52 cases of advanced colorectal carcinoma and surrounding mucosa. All of the tumor-neighboring mucosa presented hyperplasia. The rates of enhanced immunoreactivity of the tumor-neighboring mucosa and of positive immunoreactivity of the carcinomas against human Bcl-2 protein and against human vasoactive intestinal polypeptide, pancreatic polypeptide and somatostatin were 78.8% and 94.2%, 82.7% and 59.6%, 78.8% and 67.3%, and 88.5% and 84.6% respectively. Double immunostaining for Bcl-2 protein and each peptide hormone revealed simultaneous expression. In contrast, that of tumor-neighboring mucosa and carcinomas to serotonin and chromogranin-A and to argyrophilia were 11.5% and 1.9%, 32.7% and 17.3%, and 26.9% and 21.2%, respectively. We concluded that tumor-neighboring crypt cells displayed not only hyperplasia but also neuroendocrine characteristics and that enhanced Bcl-2 protein immunoreactivity correlated with tumor occurrence in the wall of the colorectum. The production of Bcl-2 protein by tumor cells and tumor-neighboring crypt cells indicates that the bcl-2 protooncogene may act not only as an inhibitor of apoptosis but also as an inducer of neuroendocrine differentiation from the latent characteristics of the endodermal stem cell.

Adult↗
PubMed1999

An aged male patient with autoimmune hepatitis complicated by hepatocellular carcinoma.

An 82-year-old male patient was admitted for liver dysfunction. Laboratory test showed the following data; aspartate aminotransferase (AST) 79 IU/l, alanine aminotransferase (ALT) 28 IU/l, total bilirubin (T. Bil) 0.9 U, zinc sulfate turbidity test (ZTT) 48.9 U, gamma-globulin 4.9 g/dl, immunoglobulin G (IgG) 5,046 mg/dl, anti-nuclear antibodies x 320, anti-mitochondrial antibodies (-), hepatitis B virus surface antigen (HBsAg) (-), HBcAb (-), anti-hepatitis C virus (anti-HCV) (-), hepatitis C virus (HCV-RNA) (-), anti-hepatitis G virus (anti-HGV) (-), alpha-fetoprotein 306.8 ng/ml, carcinoembryonic antigen (CEA) 2.3 ng/ml, carbohydrate antigen (CA) 19-9 77.2 U/ml. Abdominal ultrasonography and computed tomography showed a large mass occupying most of the right lobe and portal thrombosis in the liver. Liver biopsy revealed cirrhosis with inactive hepatitis in the nontumorous lesion and well-differentiated hepatocellular carcinoma in the tumorous lesion. We report a rare case of an aged male patient with autoimmune hepatitis complicated by hepatocellular carcinoma.

Aged↗
PubMed1999

Recent epidemiologic trends in alveolar echinococcosis prevalence in humans and animals in Hokkaido.

We investigated chronological and geographical changes of alveolar echinococcosis (AE) prevalence in 14 administrative districts of Hokkaido based on the data of our epizootiologic and seroepidemiologic surveys. The results suggest that the chronological transitions of the enzootic state of AE in Hokkaido markedly reflect those of human AE prevalence, and that new prevalence of human AE has been emerging from central and western Hokkaido.

Animals↗
PubMed1999

[Investigation of factors affecting psychological depression in child-rearing mothers].

Child-rearing mothers (n = 1,459) were surveyed by questionnaire in regard to their feeling psychologically depressed and for prevalence of some conditions in their life frequently referred to as affecting factors that may be rated to the depression. A working scale of depression for this research was developed through a Multi Dimensional Scaling Procedure. Crobach's alpha of this scale was as large as 0.77 and correlational coefficients of this scale between each question were greater than 0.46 and less than 0.70. This scale was considered sufficient for the purpose of this research to obtain depressive scores. Coefficients in multiple regression analysis predictive for depressive score were obtained. Correlations were also calculated between depressive score and the factors stratifying by mothers' demographic factors. Out of a total 21.6 coefficients only 14 were greater than 0.30 and no factor showed coefficients greater than 0.80 through all the stratifications. None of the factors analyzed in this study appear to satisfactorily explain psychological depression. Therefore further search for real factors that affect the psychological depression in child-rearing mothers is required.

Adult↗
PubMed1999

Monoclonal antibodies specific to carbohydrates of Echinococcus multilocularis.

To investigate the complexity of epitopes presented on Echinococcus multilocularis (E.m.) metacestode carbohydrates, a panel of monoclonal antibodies (MoAbs) was generated and characterized. Thirty of the clones were obtained and classified into three types (types I to III) based on Western blotting (WB) and dot-ELISA. One MoAb (type I) appeared to react with one of the carbohydrate antigens (C-antigens) located at 30-35 kDa, and was the most effective diagnostic antigen for human alveolar hydatid disease (AHD) in Hokkaido, Japan. The second group (15 clones) of MoAb (type II) reacted with another C-antigen; one which also induced antibody response in AHD patients. The third group (14 clones) of MoAb (type III) reacted with other C-antigens both in ELISA and dot-ELISA, but did not react in WB. Cross-reaction to the antigens of Echinococcus granulosus was faintly observed in only the type I-MoAb by dot-ELISA. In the immunohistological studies, all of the MoAbs reacted strongly with the laminated layer though not with protoscoleces in metacestode tissue prepared from experimentally infected cotton rats. Tissue sections treated with sodium periodate lost their immunoreactivity, suggesting that these MoAbs recognized carbohydrate epitopes of the E.m. metacestode.

Animals↗
PubMed1998

Development of a highly sensitive chemical method for detecting alpha2-->8-linked oligo/polysialic acid residues in glycoproteins blotted on the membrane.

A highly sensitive chemical method for detecting alpha2-->8-linked oligo/polysialic acid (oligo/polySia) chains was developed, including (i) periodate oxidation, reduction with sodium borohydride, and subsequent acid hydrolysis, giving rise to C7 analogues and intact C9 compounds from nonreducing terminal and internal sialic acid residues, respectively; (ii) fluorescent labeling of these C7 and C9 compounds with 1,2-diamino-4,5-methylenedioxybenzene (DMB); and (iii) quantitation of theseDMB derivatives on fluorometric high-performance liquid chromatography. As little as 1 ng of internal sialic acid residues of oligo/polySia chains, the existence of which indicates the presence of oligo/polySia structure, was detectable by this method. This fluorometric C7/C9 analysis was successfully applied to glycoproteins blotted onto a slit of polyvinylidene fluoride membranes and suggested the presence of some novel oligoSia-containing glycoproteins in pig embryonic brains.

Animals↗
PubMed1998

Identification of oligo-N-glycolylneuraminic acid residues in mammal-derived glycoproteins by a newly developed immunochemical reagent and biochemical methods.

The occurrence of the alpha2-->8-linked oligomeric form of N-glycolylneuraminic acid (oligo-Neu5Gc) residues in mammalian glycoproteins was unequivocally demonstrated using a newly developed anti-oligo/poly-Neu5Gc monoclonal antibody as well as by chemical and biochemical methods. First, the antibody, designated mAb.2-4B, which specifically recognized oligo/poly-Neu5Gc with a degree of polymerization of >2, was developed by establishing a hybridoma cell line from P3U1 myeloma cells fused with splenocytes from an MRL autoimmune mouse immunized with dipalmitoylphosphatidylethanolamine-conjugated oligo/poly-Neu5Gc. Second, oligo-Neu5Gc was shown to occur in glycoproteins derived from pig spleen by Western blot analysis using mAb.2-4B, which was also confirmed by fluorometric high performance liquid chromatographic analysis of the product of periodate oxidation/reduction/acid hydrolysis of the purified glycopeptide fractions and by TLC and 600-MHz 1H NMR spectroscopic analysis of their mild acid hydrolysates. Finally, the ubiquitous occurrence of oligo-Neu5Gc chains as glycoproteinaceous components in Wistar rat tissue was immunochemically indicated. This is the first example demonstrating the diversity in oligo/poly-Sia structure in mammalian glycoproteins, where only poly-N-acetylneuraminic acid is known to occur. Such diversity in oligo/poly-Sia structure also implicates a diverged array of biological functions of this glycan unit in glycoproteins.

Animals↗
PubMed1998

Mutations in the interferon-sensitivity determining region of hepatitis C virus and transcriptional activity of the nonstructural region 5A protein.

Amino acid (aa) mutations in the interferon-sensitivity determining region (ISDR) (aa position 237-276 of the nonstructural region 5A [NS5A] protein consisting of 447 amino acids) of hepatitis C virus (HCV) are related to increased interferon sensitivity and low viral load, but its mechanism has not been clarified. Recently, the NS5A protein has been reported to have a transcriptional activation function, like other viral transactivator proteins known to repress interferon-induced gene expression, and the ISDR overlaps one of the acidic amino acid regions, putative domains conferring this activity. In the present study, we investigated the transcriptional activation function of the ISDR itself and the effect of amino acid mutations in the ISDR on this activity. The full-length or truncated NS5A cDNA with different ISDR sequences was cloned into a yeast or mammalian expression vector to form a fusion protein consisting of the GAL4 DNA-binding domain (GAL4-DBD) and NS5A protein. Following transfection, the transcriptional activities of these constructs were determined using beta-galactosidase (yeast) or chloramphenicol acetyltransferase (CAT) (mammalian cell) reporter gene expression under the control of GAL4 binding sites. In yeast, both the full-length sequence of NS5A-R (a clone with one aa mutation in the ISDR) and NS5A-S (a derivative of NS5A-R with six aa mutations in the ISDR) had no distinguishable transcriptional activity, whereas an amino-terminal deletion construct of NS5A-R (aa position 228-447) lacking 227 aa, showed remarkable activity with the relative value of 117.0 over that of the backbone vector. The same deletion mutant of NS5A-S produced five times higher activity with the relative value of 575.0, indicating that aa mutations in the ISDR profoundly affect this transcriptional activity. In a hepatoma cell line, HuH-7, the transcriptional activity was more prominent with a construct consisting of only the ISDR and short flanking sequences (aa 228-284) than larger deletion constructs of NS5A-R. Analysis using six different ISDR clones revealed that different mutations enhanced this activity to various extent compared with the wild-type ISDR. In particular, site-directed mutagenesis targeted to the aa position 252 showed that this aa residue had profound influence on the activity. These results suggest that the ISDR has a transcriptional activity, and it is enhanced by aa mutations that are also related to decreased viral load and increased interferon sensitivity. The possible association between transcriptional activation and interferon sensitivity or viral replication should be studied further.

Amino Acid Sequence↗
PubMed1998

The sodium channel has four domains surrounding a central pore.

The voltage-gated sodium channel generates the action potential. This 300-kDa protein has four homologous regions, which are also homologous to the voltage-sensitive tetrameric potassium channel. We isolated sodium channels from Electrophorus electricus electroplax by detergent solubilization and immunoaffinity chromatography and studied their structure by electron microscopy of negatively stained specimens. Different projections were aligned, classified, and averaged. In side view, the channel protein exhibits the shape of a truncated cone, 14 nm in height. One end has a diameter of 12 nm and is asymmetric, while the other is more symmetric and has a diameter of 7-10 nm. In top views, the sodium channel appears to consist of four domains of different size and to have a stain-filled pore in the center.

Animals↗
PubMed1998

ATP release caused by bradykinin, substance P and histamine from intact and cultured smooth muscles of guinea-pig vas deferens.

Histamine (60 microM) produced ATP release from segments of guinea-pig vas deferens which was blocked by pyrilamine and triprolidine, H1-blockers, but not by ranitidine, an H2-blocker. The evoked-release was inhibited by the mitochondrial inhibitors, carbonyl cyanide-m-chlorophenylhydrazone (CCCP) and oligomycin. Bradykinin (BK) and substance P (SP) also caused substantial and moderate release of ATP, respectively. The BK-evoked release of ATP was inhibited by HOE140, a B2-antagonist, but not by [Des-Arg10] HOE140, a B1-antagonist. On the other hand, VIP, angiotensin II (AII) and cholecystokinin-octapeptide (CCK-8) failed to elicit a measurable release of ATP. Histamine and BK also enhanced the release of ATP from superfused cultured smooth muscle cells. These results suggest that ATP may be released as an autacoid from the smooth muscles in the presence of these chemical mediators.

Adenosine Triphosphate↗
PubMed1998

Flow cytometric method to detect lymphocyte transformation in drug-allergic hepatic injury.

Flow cytometric methods for the analysis of incorporated bromodeoxyuridine are extremely rapid and simple. We investigated whether these methods were useful for detecting drug-allergic hepatic injury in 18 patients with drug-allergic hepatic injury, 18 healthy controls, and 9 nonallergic patients receiving drugs. Peripheral blood mononuclear cells were stimulated with drug solutions. Incorporation of bromodeoxyuridine was detected after labeling with FITC, and S-phase cells were counted by flow cytometry. Percentages of S-phase cells in drug-stimulated culture minus those in spontaneous cultures were less than 1% in both healthy controls and nonallergic patients receiving drugs. Taking 1% as the upper limit, 13 patients (72%) were judged as positive. After the in vitro addition of interleukin-2, two patients among five who had been judged as negative were judged as positive. Lymphocyte transformation test by flow cytometry may be useful in the diagnosis of drug-allergic hepatic injury.

Case-Control Studies↗