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Biomedical subjects

T Nagano

Publications and source records attributed to T Nagano.

At least 109 records · Page 6Linked to original sources
PubMed1999

[Case of stage IVb gastric cancer in which favorable anti-tumor effect and good QOL were observed due to UFTP therapy after low-dose CDDP-tegafur therapy].

A patient with stage IVb advanced gastric cancer, who was Group 4 lymph node metastasis positive, underwent two postoperative courses of low-dose CDDP-tegafur therapy (800 mg/body/day of tegafur + 5 mg/body/5 administrations, 2 days of rest, of cisplatin). UFTP therapy (400 mg/body/day of UFT + 5 mg/body/twice weekly of cisplatin) was thereafter given on an outpatient basis. The patient has now been receiving this therapy for one year and six months. The anti-tumor effect has been maintained and the tumor has been reduced in size by 89% without any adverse reactions. A good QOL has been observed. The present therapy can be performed safely at home and appears to be a favorable treatment from the viewpoint of QOL.

Adenocarcinoma↗
PubMed1998

Direct evidence of NO production in rat hippocampus and cortex using a new fluorescent indicator: DAF-2 DA.

The biological functions of nitric oxide in the neuronal system remain controversial. Using a novel fluorescence indicator, DAF-2 DA, for direct detection of NO, we examined both acute rat brain slices and organotypic culture of brain slices to ascertain NO production sites. The fluorescence intensity in the CA1 region of the hippocampus was augmented, especially after stimulation with NMDA, in acute brain slices. This NO production in the CA1 region was also confirmed in cultured hippocampus. This is the first direct evidence of NO production in the CA1 region. There were also fluorescent cells in the cerebral cortex after stimulation with NMDA. Imaging techniques using DAF-2 DA should be very useful for the clarification of neuronal NO functions.

Animals↗
PubMed1998

Detection and imaging of nitric oxide with novel fluorescent indicators: diaminofluoresceins.

Nitric oxide is a gaseous, free radical which plays a role as an intracellular second messenger and a diffusable intercellular messenger. To obtain direct evidence for NO functions in vivo, we have designed and synthesized diaminofluoresceins (DAFs) as novel fluorescent indicators for NO. The fluorescent chemical transformation of DAFs is based on the reactivity of the aromatic vicinal diamines with NO in the presence of dioxygen. The N-nitrosation of DAFs, yielding the highly green-fluorescent triazole form, offers the advantages of specificity, sensitivity, and a simple protocol for the direct detection of NO (detection limit 5 nM). The fluorescence quantum efficiencies are increased more than 100 times after the transformation of DAFs by NO. Fluorescence detection with visible light excitation and high sensitivity enabled the practical assay of NO production in living cells. Membrane-permeable DAF-2 diacetate (DAF-2 DA) can be used for real-time bioimaging of NO with fine temporal and spatial resolution. The dye was loaded into activated rat aortic smooth muscle cells, where the ester bonds are hydrolyzed by intracellular esterase, generating DAF-2. The fluorescence in the cells increased in a NO concentration-dependent manner.

Animals↗
PubMed1998

Direct evidence of nitric oxide production from bovine aortic endothelial cells using new fluorescence indicators: diaminofluoresceins.

The measurement of nitric oxide (NO) is important for direct examination of the regulatory roles of NO in various biological systems. Diaminofluoresceins (DAFs), new fluorescence indicators for NO, were applied to detect the release of NO from bovine aortic endothelial cells (ECs). DAFs react with NO to yield the corresponding green-fluorescent triazolofluoresceins, which provide the advantages of specificity, sensitivity and a simple protocol for the direct detection of NO. Using these DAFs, we could detect the generation of NO not only from inducible NO synthase expressed in macrophages, but also from constitutive NO synthase expressed in ECs.

Animals↗
PubMed1998

Up-regulation of phosphorylation of focal adhesion kinase and paxillin by combination of substance P and IGF-1 in SV-40 transformed human corneal epithelial cells.

We previously reported that substance P (SP) and insulin-like growth factor-1 (IGF-1) synergistically facilitate corneal epithelial migration in vitro and in vivo. We wanted to determine whether proteins responsible for cellular attachment are activated in corneal epithelial cells. To do this, we examined changes in tyrosine phosphorylation in focal adhesion kinase (FAK) and paxillin in cultured SV-40 transformed human corneal epithelial cells (HCE cells). HCE cells were cultured in the absence or presence of either SP (2 x 10(-5) M) or IGF-1 (10 ng/ml) or both SP and IGF-1. Treatment of HCE cells by either SP or IGF-1 alone did not alter tyrosine phosphorylation in either FAK or paxillin. However, the combination of SP and IGF-1 significantly increased tyrosine phosphorylation in both FAK and paxillin. In contrast, the combination of SP and IGF-1 was not observed to produce synergistic effects on the activation of mitogen-activated protein kinase in HCE. These results show that the synergistic effects of SP and IGF-1 on corneal epithelial wound healing were expressed through activation of the integrin, FAK, and paxillin system.

Biological Transport↗
PubMed1998

Differentially expressed olfactomedin-related glycoproteins (Pancortins) in the brain.

Messenger RNA differential display is conducted to search for genes that are expressed in a region-specific pattern in the rodent brain. Eleven novel gene fragments are isolated. One of these genes which we call pancortin, based on its predominant mRNA expression in the cerebral cortex of the adult, is studied. These pancortin cDNA clones are grouped into four different types of cDNA, designated as pancortin-1 to -4. All pancortin cDNAs share a common sequence in the middle of their structure, having two alternative sequences at both 5'- and 3'-ends, respectively. Deduced amino acid sequence shows that all pancortins have sequences of hydrophobic amino acids at N-terminus and no obvious membrane spanning regions. In situ hybridization histochemistry using oligonucleotide probes specific for 5'- and 3'-end variable parts has revealed that these four pancortin mRNAs are expressed differentially in the adult rodent brain. Robust expression of pancortin-1 and -2 mRNA is observed in the cerebral cortex (including the hippocampus and the olfactory bulb). However, little of pancortin-3 and -4 mRNA is observed there. In the cortex, some neurons are stained by an antibody raised against Pancortin. Immuno-electron microscopic study has revealed that Pancortin-like immunoreactive products are localized mainly in the endoplasmic reticulum and not in the Golgi apparatus indicating that Pancortins are the endoplasmic reticulum-anchored proteins. Our results suggest that each Pancortin is differentially regulated and may perform different functions in the brain.

Amino Acid Sequence↗
PubMed1998

Distribution of mRNA encoding Tat-binding protein-1 (TBP-1), a component of 26S proteasome, in the rat brain.

Cellular localization of Tat-binding protein-1 (TBP-1) mRNA is studied in the rat central nervous system (CNS) by in situ hybridization histochemistry. TBP-1 is one of the molecules which interact with HIV Tat and influence HIV amplification. Also, TBP-1 is recognized as a component of a 19S regulatory subunit of the 26S proteasome which degrades ubiquitinated proteins and is essential for a remarkably wide range of cellular processes, including vesicle fusion, proteolysis, peroxisomal and mitochondrial biogenesis and transcription. A detectable amount of TBP-1 mRNA exists widely in neurons but with high heterogeneity in the CNS. Many motor neurons, e.g. those in the oculomotor nucleus, trochlear nucleus, motor trigeminal nucleus, facial nucleus and hypoglossal nucleus, are TBP-1 mRNA positive. In addition, neurons in the sensory nuclei, such as the mesencephalic trigeminal nucleus and the nucleus ambiguus, and many cortical neurons are TBP-1 mRNA positive. These results suggest that TBP-1 is one of the basic molecules in the brain and that the expression of TBP-1 mRNA is differentially regulated at the cellular level, probably reflecting the rate of protein turnover as a whole.

ATPases Associated with Diverse Cellular Activitie↗
PubMed1998

Analysis of the superantigen-producing ability of Yersinia pseudotuberculosis strains of various serotypes isolated from patients with systemic or gastroenteric infections, wildlife animals and natural environments.

Yersinia pseudotuberculosis is a pathogen causing gastroenteritis as well as acute and systemic infections. This organism produces a superantigenic exotoxin, designated Y. pseudotuberculosis-derived mitogen (YPM). We consider this exotoxin to be the primary pathogen of the systemic type infection. In this study, we examined 101 Y. pseudotuberculosis strains isolated from various sources, patients with the systemic or the gastroenteric type of infections, wildlife animals and natural environments for the presence of the YPM gene and the production of YPM or other related superantigens. We found that all of the strains isolated from patients with systemic type infection carried the YPM gene and produced YPM. A certain proportion of the organisms isolated from patients with the gastroenteric type infection, wildlife animals or natural environments did not carry the YPM gene nor produced superantigens. These results suggest that YPM is involved in the pathogenesis of the systemic type of Y. pseudotuberculosis infection.

Animals↗
PubMed1998

Lactoferrin suppresses loss of corneal epithelial integrity in a rabbit short-term dry eye model.

Human tear fluid contains lactoferrin at the highest concentration. In patients with dry eye such as Sjogren's syndrome, the concentration of lactoferrin in the tears is approximately half the normal value. The present study utilizes a short-term rabbit dry eye model to evaluate if lactoferrin containing eye drops can reverse any of the damage produced by blockage of blinking with an ocular speculum. Damage was evaluated based on the extent of methylene blue staining in histological sections. After 3 h of desiccation, the amount of extractable dye recovered following sacrifice increased by more than 4-fold in the vehicle-treated eyes. However, in those rabbits treated with 1% lactoferrin, dye recovery was only 40% of the value in the vehicle-treated eyes. Between 1-3 h and over a concentration range from 0.01 to 1% lactoferrin, the decreases in staining were both time and concentration dependent. Alternatively, if 1% lactoferrin was applied during the desiccation period, there was partial restoration of corneal epithelial integrity. These results suggest that lactoferrin may be of therapeutic value in decreasing the loss of corneal epithelial integrity in dry eye.

Animals↗
PubMed1998

Emerging roles of Dlg-like PDZ proteins in the organization of the NMDA-type glutamatergic synapse.

A group of proteins found at cell-cell junctions have a common structural domain, called PDZ-a stretch of 80-90 amino acid residues initially identified in the three proteins PSD-95, Dlg, and ZO-1. This domain is found in various proteins from bacteria to mammals and is involved in protein-protein interaction. Recently, many proteins containing this domain were identified in the nervous system by molecular cloning and shown to interact with other synaptic proteins, including various transmitter receptors, ion channels, and signal transducers. These PDZ-containing proteins are mostly located near the synaptic membrane and are, therefore, speculated to transport associated proteins to the synapse and/or anchor them at the synaptic sites. Alternatively, as a single molecule often contains multiple PDZ domains that can interact with each other, it may cluster all these synaptic molecules and facilitate their signaling at synaptic sites. This review focuses on the best characterized PDZ-containing proteins that interact with N-methyl-D-aspartate (NMDA)-type glutamate receptors and discusses their functions in synaptic organization.

Amino Acid Sequence↗
PubMed1998

Sebaceous carcinoma of the submandibular gland with high-grade malignancy: report of a case.

A case of sebaceous carcinoma arising in the left submandibular gland of a 66-year-old man is reported. The clinical and pathological examinations revealed a carcinoma, which was to salivary gland in origin, with regional lymph nodal metastases. Pathological findings showed features of high-grade sebaceous carcinoma with spindle myoepitheliomatous differentiation. Neither squamous cell nor duct epithelial-like cell differentiation was noted. Immunohistochemically, tumor cells were positive for cytokeratin, S-100 protein and vimentin. Lipid was demonstrated in the cytoplasm of the tumor cells. Ultrastructurally, tumor cells contained numerous intracytoplasmic lipid droplets. Myoepitheliomatous differentiation is rare in sebaceous carcinoma of the salivary gland. Presented is the second reported case of sebaceous carcinoma arising in the submandibular gland.

Aged↗
PubMed1998

Improved nitric oxide detection using 2,3-diaminonaphthalene and its application to the evaluation of novel nitric oxide synthase inhibitors.

A specific and sensitive detection method for nitric oxide (NO) in living cells and tissue culture systems is required in the search for novel NO synthase (NOS) inhibitors. We have improved a fluorometric determination with 2,3-diaminonaphthalene (DAN) by the addition of 2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl (PTIO) as an oxidant to form NO2 from NO. This method is 3 times more sensitive than that without PTIO, and is suitable for examining the NOS-inhibitory activity of large numbers of test compounds using a 96-well microplate reader. The improved method was applied to N-monomethyl-L-arginine (L-NMMA) as a known inhibitor and the derivatives of 2-phenyl-1,2-benzisoselenazol-3(2H)-one as teat compounds in order to investigate the effect of these compounds on NO production from activated rat aortic smooth muscle cells. The results obtained indicate that this method is suitable for the rapid assay of large numbers of test compounds.

2-Naphthylamine↗
PubMed1998

Real time measurement of nitric oxide released from cultured endothelial cells.

Direct detection of nitric oxide (NO) is essential for understanding the precise mechanism of its production from endothelial cells. Previously, we developed an NO detection system based on the chemiluminescence reaction between NO and luminol-H2O2. Here, we have applied this system to cultured endothelial cells for the direct and on-time measurement of NO. The perfusate from cultured endothelial cells was continuously mixed with luminol-H2O2. N(G)-monomethyl-L-arginine (L-NMMA) (10(-4) M) decreased the chemiluminescence signal of NO, suggesting the existence of basal NO release. Bradykinin (10(-8) M-10(-6) M) increased the NO signal (10(-6) M; 5.1+/-0.4 fmol/min, corresponding to 1.7 pM in the perfusate), and this was inhibited by 10(-4) M L-NMMA (1.8+/-0.3 fmol/min). These results corresponded to the changes in cGMP levels in RFL-6 cells, which provide an NO bioassay system. We conclude that the luminol-H2O2 system is useful for the direct and continuous measurement of NO from cultured endothelial cells.

Animals↗
PubMed1998

Hepatoprotective effect of Fe-TPEN on carbon tetrachloride induced liver injury in rats.

Fe(II)-tetrakis-N,N,N',N'(2-pyridylmethyl) ethylenediamine (Fe-TPEN) catalyzes the dismutation of superoxide, and blocks the toxic effect of paraquat on Escherichia coli growth and survival. We examined antioxidative effects of Fe-TPEN on lipid peroxidation and t-butyl hydroperoxide induced cell damage. Fe-TPEN inhibited the FeSO4/H2O2 induced lipid peroxidation in the rat liver homogenates with an IC50 value of 30.2 microM, and protected Ac2F cell damage by t-butyl hydroperoxide in a dose-dependent manner (EC50 value is 2.6 microM). Also, hepatoprotective effect of Fe-TPEN (5 mg/kg, i.p.) was investigated using CCl4 induced liver injury in rats. This complex inhibited the elevation of serum alanine aminotransferase (AST) and aspartate aminotransferase (ALT) levels in CCl4 induced liver injuries, and improved submassive necrosis and fatty degeneration of the hepatocytes. Fe-TPEN also prevented the loss of total and nonprotein SH contents, glutathione peroxidase and glutathione-S-transferase activity in cytosol of rat liver. Although the exact mechanism of action is not clear, antioxidative properties as well as attenuation of hepatocellular defense systems by Fe-TPEN seem to be important on its potent hepatoprotective effect in CCl4-intoxicated rat.

Animals↗
PubMed1998

Development of a fluorescent indicator for nitric oxide based on the fluorescein chromophore.

Endogenous nitric oxide (NO) appears to modulate many physiological and pathophysiological processes. In order to obtain direct evidence for NO functions in vivo, we have developed 4,5-diaminofluorescein (DAF-2) as a novel fluorescent indicator for NO. Green-fluorescent triazolofluorescein formed by the reaction of NO and DAF-2 affords high sensitivity for NO (detection limit: 5 nM). Membrane-permeable DAF-2 diacetate (DAF-2 DA) was loaded into activated rat aortic smooth muscle cells, where the ester bonds are hydrolyzed by intracellular esterase, generating DAF-2. The fluorescence in the cells increased in a NO concentration-dependent manner. This imaging method should be useful for studies of the dynamic biological actions of NO at the molecular level with fine temporal and spatial resolution.

Animals↗
PubMed1998

Cytotoxic actions of FTY720, a novel immunosuppressant, on thymocytes and brain neurons dissociated from the rat.

Effects of FTY720 (2-amino-2-(2-[4-octylphenyl]ethyl)-1,3-propanediol HCl), a novel immunosuppressant, were examined on neurons and thymocytes respectively dissociated from rat brains and thymus glands using a flow cytometer to see if FTY720 exerts cytotoxic actions not only on spleen cells as previously reported but also on the other cells. FTY720 at a concentration of 10 microM deteriorated almost all of the thymocytes, while it was not the case for brain neurons. FTY720 increased the intracellular concentration of Ca2+ ([Ca2+]i) of thymocytes in both the presence and absence of external Ca2+, although the [Ca2+]i increased by FTY720 in the presence of external Ca2+ was much greater than that in the absence of external Ca2+. Thus, FTY720 may increase the membrane permeability of Ca2+ and release Ca2+ from intracellular Ca2+ stores in thymocytes. Furthermore, the number of thymocytes stained with ethidium, a dye impermeant to intact membranes, time-dependently increased after drug application. Therefore, FTY720 at concentrations of 3 - 10 microM non-specifically increases the membrane permeability of thymocytes, resulting in necrotic cell death, although FTY720 at micromolar concentrations was reported to induce apoptosis of spleen cells.

Animals↗
PubMed1998

RpoS-dependent expression of the second lysine decarboxylase gene in Escherichia coli.

The second lysine decarboxylase gene (ldc) is at 4.7 min on the Escherichia coli chromosome [Kikuchi et al., J. Baceriol. 179, 4486-4492 (1997)]. This report showes that the expression of ldc as well as cadA was induced at stationary phase in the wild type of E. coli. The ldc was not expressed in a rpoS deletion mutant of E. coli at any growing stage. In contrast, cadA was expressed in the rpoS mutant. Thus, we conclude that the expression of ldc but not cadA at stationary phase is regulated by a RpoS-dependent mechanism (s) in E. coli.

Adenosine Triphosphatases↗