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Biomedical subjects

M Goto

Publications and source records attributed to M Goto.

At least 127 records · Page 7Linked to original sources
PubMed2001

Stenosis differentially affects subendocardial and subepicardial arterioles in vivo.

The presence of a coronary stenosis results primarily in subendocardial ischemia. Apart from the decrease in coronary perfusion pressure, a stenosis also decreases coronary flow pulsations. Applying a coronary perfusion system, we compared the autoregulatory response of subendocardial (n = 10) and subepicardial (n = 12) arterioles (<120 microm) after stepwise decreases in coronary arterial pressure from 100 to 70, 50, and 30 mmHg in vivo in dogs (n = 9). Pressure steps were performed with and without stenosis on the perfusion line. Maximal arteriolar diameter during the cardiac cycle was determined and normalized to its value at 100 mmHg. The initial decrease in diameter during reductions in pressure was significantly larger at the subendocardium. Diameters of subendocardial and subepicardial arterioles were similar 10--15 s after the decrease in pressure without stenosis. However, stenosis decreased the dilatory response of the subendocardial arterioles significantly. This decreased dilatory response was also evidenced by a lower coronary inflow at similar average pressure in the presence of a stenosis. Inhibition of nitric oxide production with N(G)-monomethyl-L-arginine abrogated the effect of the stenosis on flow. We conclude that the decrease in pressure caused by a stenosis in vivo results in a larger decrease in diameter of the subendocardial arterioles than in the subepicardial arterioles, and furthermore stenosis selectively decreases the dilatory response of subendocardial arterioles. These two findings expand our understanding of subendocardial vulnerability to ischemia.

Animals↗
PubMed2001

TNF-alpha increases sensitivity to LPS in chronically catheterized rats.

Patients with severe trauma injury are transiently exposed to increased serum concentrations of tumor necrosis factor-alpha (TNF-alpha). These patients are susceptible to the development of multisystem organ failure (MSOF) triggered by subsequent exposure to bacterial toxins either via infection or increased intestinal permeability. We simulated the cytokine response of trauma by infusing 0.8 or 8.0 microg/kg of TNF-alpha (priming dose) into chronically catheterized rats. After 48 h, rats were challenged with endotoxin [lipopolysaccharide (LPS); 10 or 1,000 microg/kg]. Animals primed with either dose of TNF-alpha and then challenged with 1,000 microg/kg of LPS demonstrated significantly increased mortality, mean peak serum concentrations of interferon-gamma (IFN-gamma), and blood lactate concentrations (P < 0.05) compared with nonprimed animals. Mean peak serum concentrations of IFN-gamma and blood lactate concentrations were increased after challenge with 10 microg/kg of LPS only in animals primed with 8.0 microg/kg of TNF-alpha. Priming with TNF-alpha did not increase mortality after challenge with 10 microg/kg of LPS. These data suggest that both TNF-alpha release and the subsequent exposure to bacterial toxins mediate the pathophysiological progression from trauma to subsequent MSOF.

Animals↗
PubMed2001

Hepatocyte attachment onto thermosensitive poly(N-isopropylacrylamide-co-N-p-vinylbenzyl-O-beta-D-galactopyranosyl-(1 --> 4)-D-gluconamide).

Temperature sensitive poly(N-isopropylacrylamide) (PIPAAM) was incorporated into hepatocyte-recognizable poly[N-p-vinylbenzyl-O-beta-D-galactopyranosyl-(1 --> 4)-D-gluconamide] (PVLA) for thermal modulating of hepatocyte attachment. The copolymer, poly(N-isopropylacrylamide-co-N-p-vinylbenzyl-O-beta-D-galactopyranosyl-(1 --> 4)-D-gluconamide) (abbreviated as [P(IPAAM-co-VLA)] (PIPAAM/PVLA = 9/1 in mol%) exhibited lower critical solution temperature (LCST) at 34 degrees C and also showed very good hepatocytes-recognizablility through the specific interaction between asialoglycoprotein receptors on the cell surfaces and galactose moiety of the copolymer. The cells attached on this copolymer were easily detached by lowering the temperature below the LCST of the copolymer. Morphological damage of the detached cell was not observed.

Acrylic Resins↗
PubMed2001

Incorporation of sulfonylurea into sugar-carrying polymers and their effects on insulin secretion from MIN6 cells in a solution state.

A hypoglycemic sulfonylurea (SU) was incorporated into non-reducing glucose-bearing polystyrene (PS) derivative for enhanced interaction with, and insulin secretion from an insulinoma cell line (MIN6). SU derivative was copolymerized with styrene having sugar moiety such as maltose or lactose. About an 80% increase in insulin secretion for poly(N-p-vinylbenzyl-D-maltonamide-co-SU) (p(VMA-co-SU)) was observed when the copolymer was added to the culture medium (SU: 25 mol%). whereas about 50% increase for poly(N-p-vinylbenzyl-D-lactonamide-co-SU) (p(VLA-co-SU)) was observed when compared with unstimulated cells. From the measurement of flow cytometry, the fluorescence intensity of MIN6 cells incubated in culture media containing FITC-labeled SU-incorporated copolymer increased remarkly owing to specific interaction between receptors in the cell membrane and SU ligands in the copolymer. When sugar and/or SU-incorporated copolymer were co-entrapped with the cells in agarose or collagen gel as an extracellular matrix for three-dimensional culture. p(VMA-co-SU) enhanced more insulin secretion from MIN6 cells than other polymers and it was found that collagen gel was more effective in insulin secretion than agarose

Animals↗
PubMed2001

Altered GalNAc-alpha-2,6-sialylation compartments for mucin-associated sialyl-Tn antigen in colorectal adenoma and adenocarcinoma.

Sialyl-Tn (STn), a mucin-associated disaccharide antigen carried by apomucins such as MUC2, plays an important role in tumor biology. However, little is known about the subcellular localization and compartments involved in STn synthesis. In this study we used immunoelectron microscopy to localize STn and MUC2 apomucin in human colorectal tissues. MUC2 apomucin was localized predominantly in the rough endoplasmic reticulum (RER) in normal colorectal mucosa (n=6), colorectal adenoma (n=8), and colorectal adenocarcinoma (n=10). STn, recognized by monoclonal antibody TKH2, was not readily detectable in normal colorectal mucosa but becomes manifest in both trans-Golgi apparatus and mucin droplets in colorectal adenoma. In colorectal adenocarcinoma, STn was localized not only in late but also in early Golgi compartments, and particularly in some RER lumens. Furthermore, electron microscopic in situ hybridization revealed that gold particles representing MUC2 mRNA are primarily localized over the RER. Our findings indicate that in colorectal adenoma STn sialylation takes place in the trans-Golgi apparatus, whereas in colorectal cancer STn sialylation occurs in all the Golgi compartments and in the RER.

Adenocarcinoma↗
PubMed2001

TNFalpha decreases gluconeogenesis in hepatocytes isolated from 10-day-old rats.

Gluconeogenesis decreases during septic shock, but its mechanism is not well known. Tumor necrosis factor alpha (TNF-alpha), which is a key cytokine in septic shock, can increase GLUT1 gene expression and glucose uptake in muscles and fatty tissues. TNF-alpha does not alter the metabolism of hepatocytes in which GLUT2 is the predominant glucose transporter. However, GLUT1 is the predominant glucose transporter in hepatocytes of 10-d-old rats. Thus, we hypothesized that TNF-alpha might increase glucose uptake and glycolysis in those cells, and decrease gluconeogenesis. In the present study, hepatocytes isolated from 10-d-old rats were incubated with TNF-alpha at the concentrations of 0, 0.98, 9.8, 98, and 980 ng/mL to evaluate TNF-alpha effects on gluconeogenesis and glucose uptake. TNF-alpha increased glucose uptake (41.1 +/- 8 to 114 +/- 21.4 micromol/10(6) cells at the concentration of 980 ng/mL of TNF-alpha) in a dose-dependent manner, and decreased gluconeogenesis (98.2 +/- 8.2 to 1.1 +/- 3.2 micromol/10(6) cells at the concentration of 980 ng/mL of TNF-alpha) in a dose-dependent manner. The decrease of glucokinase mRNA and GLUT1 mRNA abundance correlated with glucose uptake (r = 0.988 and 0.997, respectively), and the decrease of phosphoenolpyruvate carboxykinase mRNA abundance correlated with the decrease of gluconeogenesis (r = 0.972). The decrease of gluconeogenesis by TNF-alpha correlated with the increase of glucose uptake (r = -0.988). We concluded that TNF-alpha reciprocally suppressed gluconeogenesis in hepatocytes isolated from 10-d-old rats.

Aging↗
PubMed2001

Anti-inflammatory effects of 5-aminosalicylic acid conjugates with chenodeoxycholic acid and ursodeoxycholic acid on carrageenan-induced colitis in guinea-pigs.

Two epimeric bile acid conjugates, 5-aminosalicylic acid-chenodeoxycholic acid (5-ASA-CDCA) and 5-aminosalicylic acid-ursodeoxycholic acid (5-ASA-UDCA), were synthesized to deliver 5-ASA to the large intestine by oral administration. The movement of the conjugates down the gastrointestinal tract and the anti-inflammatory effects on ulcerative colitis were investigated by administering the conjugates to guinea-pigs with an inflammatory bowel disease induced by 2% degraded carrageenan solution. The conjugates were protected from deconjugation in stomach and small intestine and reached the caecum and the colon, where 5-ASA was more easily liberated from 5-ASA-CDCA than from 5-ASA-UDCA. The conjugates at doses equivalent to 50 or 150 mg kg(-1) 5-ASA were orally administered once a day for 4 weeks from the 15th day after starting carrageenan treatment. The body weights and the bleeding scores of occult blood in faeces were measured during the experiment. The number of ulcers in the caecum and the colon were counted after killing the guinea-pigs at the end of the experiment. Rapid onset of efficacy was shown by a significant reduction in bleeding scores within a week after administration of the conjugates. Treatment with the lower dose of 5-ASA-CDCA showed a recovery of body weight and a significantly decreased number of ulcers in the caecum, and the ulcers in the colon had completely disappeared bythe end of the experiment. There was a good correlation found between the number of ulcers in the caecum and the bleeding scores of occult blood in faeces. The findings indicate that both conjugates were sufficiently delivered to the large intestine without deconjugation and that the lower dose of 5-ASA-CDCA is enough for treatment of ulcerative colitis in colonic inflammatory bowel diseases.

Animals↗
PubMed2001

Practical production of (S)-1,2-propanediol and its derivative through baker's yeast-mediated reduction.

The enantiomeric excess (ee) of (S)-1,2-propanediol produced by baker's yeast-mediated reduction of 1-acetoxy-2-propanone was improved to 96% ee by a fed-batch operation of the substrate. A similar reduction of 1-benzoyloxy-2-propanone stopped because of the inhibition toward the enzymes for NADPH regeneration by the reduction product. The inhibition was prevented using resin that adsorbs the product from the reaction mixture, and 70 g/l substrate was reduced yielding (S)-1-benzoyloxy-2-propanol at > 99% ee.

Journal Article↗
PubMed2001

Catalytic activity of laccase hosted in reversed micelles.

Nanostructured reversed micelles induce a high laccase activity in organic solvents, because enzymes can maintain their highly dimensional structure in water pools of reversed micelles [RMs]. Laccase attracts considerable attention as a novel industrial enzyme due to its high capability to catalyze the oxidation of aromatic compounds. The catalytic activities of lyophilized laccase and laccase entrapped in RMs were compared using an oxidative reaction. Laccase hosted in an anionic RM effectively catalyzed the oxidative reaction in various organic solvents, while lyophilized laccase exhibited no such catalytic activity. To optimize the preparation and reaction conditions for laccase in RMs, we examined the effects of pH of water pools of RMs, the concentrations of both enzyme and surfactant for the preparation of RMs, the hydration ratio (Wo), and the reaction temperature on laccase catalytic activity in organic media. Laccase entrapped in RMs exhibited the highest catalytic activity in isooctane under the following conditions: bis-2-ethylhexyl sulfosuccinate sodium salt (AOT) of 100 mM, pH 6.0, Wo=40, and reaction temperature of 60 degrees C. Under the optimum conditions, environmental pollutants such as bisphenol A, 2,4-dichlorophenol and 2,4,6-trichlorophenol were effectively degraded in 3 h.

Journal Article↗
PubMed2001

Importance of the carbohydrate-binding module of Clostridium stercorarium Xyn10B to xylan hydrolysis.

The Clostridium stercorarium xylanase Xyn10B is a modular enzyme comprising two thermostabilizing domains, a family 10 catalytic domain of glycosyl hydrolases, a family 9 carbohydrate-binding module (CBM), and two S-layer homologous (SLH) domains [Biosci. Biotechnol. Biochem., 63, 1596-1604 (1999)]. To investigate the role of this CBM, we constructed two derivatives of Xyn10B and compared their hydrolytic activity toward xylan and some preparations of plant cell walls; Xyn10BdeltaCBM consists of a catalytic domain only, and Xyn10B-CBM comprises a catalytic domain and a CBM. Xyn10B-CBM bound to various insoluble polysaccharides including Avicel, acid-swollen cellulose, ball-milled chitin, Sephadex G-25, and amylose-resin. A cellulose binding assay in the presence of soluble saccharides suggested that the CBM of Xyn10B had an affinity for even monosaccharides such as glucose, galactose, xylose, mannose and ribose. Removal of the CBM from the enzyme negated its cellulose- and xylan-binding abilities and severely reduced its enzyme activity toward insoluble xylan and plant cell walls but not soluble xylan. These findings clearly indicated that the CBM of Xyn10B is important in the hydrolysis of insoluble xylan. This is the first report of a family 9 CBM with an affinity for insoluble xylan in addition to crystalline cellulose and the ability to increase hydrolytic activity toward insoluble xylan.

Catalysis↗
PubMed2001

A handy detection cell for end-column electrochemical detection in capillary electrophoresis.

A handy and simple detection cell was constructed using a mixing joint for end-column electrochemical detection in capillary electrophoresis (CE). The cell allows for positioning of the working electrode at the end of the separation capillary without the aid of micropositioners. The design facilitates the exchange of electrodes and capillaries without the need to refabricate the entire capillary-electrode setup. The cell can be assembled in a short period of time. Alignment with the joint screw proved to be reproducible for working electrodes of copper and gold. The advantages of reduced time and low cost make the device very attractive for the routine analysis of electroactive species, such as carbohydrates and their derivatives, purine bases and nucleosides, amino acids, and catecholamines etc. by CE with electrochemical detection.

Journal Article↗
PubMed2001

Non-aqueous capillary electrophoresis of p-quinone anion radicals.

The electrophoretic detection of two kinds of p-quinone anion radicals arising from the electrolysis of benzoquinone and chloranil was achieved by employing an acetonitrile medium. Sufficient dehydration of a running solution was necessary for the detection of the benzoquinone anion radical. Oxygen in the running solution also caused a serious decrease in the amount of the benzoquinone anion radical during electrophoresis. The addition of methanol as a hydrogen-donor decreased the electrophoretic mobility of the benzoquinone anion radical significantly, while that of the chloranil anion radical was little changed. This result is interpreted in terms of hydrogen-bonding interaction between the p-quinone anion radicals and methanol, reflecting the magnitude of their proton-accepting ability (benzoquinone anion radical > chloranil anion radical).

Anions↗
PubMed2001

Outbreak of Chinese herb nephropathy in Japan: are there any differences from Belgium?

OBJECTIVE: The purpose of this article was to study and clarify the features of Chinese herb nephropathy (CHN) in Japan. PATIENTS AND METHODS: The subjects consisted of patients diagnosed as having CHN in Saiseikai Nakatsu Hospital and of those reported in the literature in Japan. We investigated the clinical and histological features of CHN patients in Japan and compared them with the Belgian cases. RESULTS: The remarkable differences were as follows: (1) high prevalence in males compared with Belgian cases, (2) Fanconi syndrome was found in most cases, (3) no patients had malignant tumors in the urinary tract. In addition, the ascribed Chinese medicines in Japan were divided into three groups: 'Tenshin-toki-shigyaku-ka-gosyuyu-syokyo-to', 'Boui-ougi-to', and others. CONCLUSION: CHN in Japan has some characteristics distinguished from Belgian nephropathy. One hypothesis is a susceptibility to aristolochic acids (AAs), which is considered to be a causative agent, may be different among races. Another is that there could be some other toxic substances affecting the clinical findings although they are not identified at present. Further studies must be undertaken to clarify these differences.

Aristolochic Acids↗
PubMed2001

[Chemotherapy of leprosy: theoretical basis of new guideline in Japan].

For the effective treatment of leprosy, we should consider that (1) more time is needed for the elimination of bacilli than ordinary bacterial infection, (2) bactericidal therapy often induces host immunity called reactions, (3) rapid treatment is needed for the reactions. Last year, ad hoc committee of Japanese Leprosy Association recommends standard treatment protocol of leprosy in Japan, which is a modification of World Health Organization's multidrug therapy. For multibacillary(MB) with bacterial index (BI > or = 3) before treatment, 2 years treatment by rifampicin, dapsone and clofazimine (MDT/MB) is necessary. When BI decrease is not satisfactory(BI value decrease < 2 steps, or final BI > or = 3) after 2 years, MDT/MB should be continued until BI negativity and loss of active lesions. Theoretical background of our proposal is described.

Drug Therapy, Combination↗
PubMed2001

Atomic resolution structure analysis of beta' polymorph crystal of a triacylglycerol: 1,2-dipalmitoyl-3-myristoyl-sn-glycerol.

The crystal structure of the beta'-2 form of a mixed chain triacylglycerol (TAG), 1,2-dipalmitoyl-3-myristoyl-sn-glycerol (PPM), was determined to a final reliability factor of 0.074. This work is the first to resolve the atomic-level structure of the beta' polymorph, which is of the highest functionality among multiple polymorphs in asymmetric TAG. In particular, fat crystals present in food emulsions are in beta', whose transformation into beta causes deterioration in their physical properties. beta'-2, one of the two beta' forms of PPM, forms a monoclinic unit cell with a space group of C2; Z = 8, a = 16.534(5) A, b = 7.537(2) A, c = 81.626(9) A; beta = 90.28(2) degrees, V = 10171(3) A(3), density = 1.018 g/cm(3), and mu = 4.96 cm(-1). The following characteristics were obtained: 1) two asymmetric units, named A and B, form a hybrid-type orthorhombic perpendicular subcell; 2) the two asymmetric units reveal different glycerol conformations: trans for sn-1 palmitic acid and sn-2 palmitic acid, but gauche for sn-3 myristic acid in A; and trans for sn-2 palmitic acid and sn-3 myristic acid, but gauche for sn-1 palmitic acid in B; 3) a unit lamellae reveals a four-chain-length structure consisting of two double-layer leaflets; 4) the two double-layer leaflets are combined end-by-end in a unit lamellae; and 5) the chain axes are alternatively inclined against the lamellar interface. -- Sato, K., M. Goto, J. Yano, K. Honda, D. R. Kodali, and D. M. Small. Atomic resolution structure analysis of beta' polymorph crystal of a triacylglycerol: 1,2-dipalmitoyl-3-myristoyl-sn-glycerol. J. Lipid Res. 2001. 42: 338--345.

Calorimetry, Differential Scanning↗
PubMed2001

Study on endocrine disrupting chemicals in wastewater treatment plants.

From July 1998 to March 1999, a study was made of a total of 27 treatment plants for the principal purpose of understanding the actual condition of endocrine disrupting chemicals (EDCs) in sewage, and the behavior of EDCs in wastewater treatment plants. The results showed actual levels of influent and effluent concentrations of EDCs in sewage. Substances detected above the minimum limit of determination were 15 for wastewater influent and 6 for effluent. Similarly, nonyl phenol ethoxylate and 17 beta-estradiol, which are highlighted as pertinent substances, were detected. It was confirmed that the reduction ratio of EDCs in treatment plants was 90% or more for almost all substances. The behavior of EDCs in general in treatment plants was also studied. As a result, the EDCs reduction effect was recognized in both the primary setting tank and biological reaction tank, though the trend varies among substances.

Endocrine System↗
PubMed2000

Epstein-Barr virus-encoded poly(A)(-) RNA supports Burkitt's lymphoma growth through interleukin-10 induction.

Akata and Mutu cell lines are derived from Burkitt's lymphoma (BL) and retain the in vivo phenotype of Epstein-Barr virus (EBV) expression that is characterized by expression of EBV-determined nuclear antigen 1 (EBNA1), EBV-encoded RNAs (EBERs) and transcripts from the BAM:HI A region (BARF0). We found that EBV-positive Akata and Mutu cell clones expressed higher levels of interleukin (IL)-10 than their EBV-negative subclones at the transcriptional level. Transfection of an individual EBV latent gene into EBV-negative Akata cells revealed that EBERs were responsible for IL-10 induction. Recombinant IL-10 enabled EBV-negative Akata cells to grow in low (0.1%) serum conditions. On the other hand, growth of EBV-positive Akata cells was blocked by treatment either with an anti-IL-10 antibody or antisense oligonucleotide against IL-10. EBV-positive BL biopsies consistently expressed IL-10, but EBV-negative BL biopsies did not. These results suggest that IL-10 induced by EBERs acts as an autocrine growth factor for BL. EBERs, EBER1 and EBER2, are non-polyadenylated RNAs and are 166 and 172 nucleotides long, respectively. The present findings indicate that RNA molecules could regulate cell growth.

Burkitt Lymphoma↗