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T Asano

Publications and source records attributed to T Asano.

At least 505 records · Page 28Linked to original sources
PubMed1993

[Study of cell populations of bronchoalveolar lavage fluid in patients with pneumonia due to Chlamydia psittaci and Mycoplasma pneumoniae].

We have performed bronchoalveolar lavage (BAL) examination in 27 cases; 5 with Chlamydial pneumonia, 7 with Mycoplasmal pneumonia and 15 in the control group (5 non-smokers, 10 smokers), and the following results were obtained. 1. In Chlamydial pneumonia and Mycoplasmal pneumonia, the cell population of alveolar macrophages in BALF decreased (p < 0.01) and that of lymphocytes increased compared with control group (p < 0.01). 2. In all cases of Mycoplasmal pneumonia without peripheral eosinophilia, the cell population of eosinophils in BALF increased compared with cases of Chlamydial pneumonia (p < 0.05). These results indicate that lymphocytes played the main role in the immune host defense in Chlamydial pneumonia, whereas infiltration of lymphocytes and eosinophils into the pneumonic lesion occurred in Mycoplasma pneumoniae infection.

Adolescent↗
PubMed1993

[Analysis of antigen non-specific suppressor T cells factor (TsF) which suppresses the generation of cytotoxic T lymphocytes].

Anti-mouse melanoma suppressor T cells clone (F12) secreted a functional factor (TsF) which suppresses the generation of cytotoxic T lymphocytes (CTL). Ts clone F12 secreted TsF into culture supernatant by stimulating for more than 12 hours with anti-CD3 monoclonal Ab. In syngeneic CTL induction system, TsF suppresses the generation of both anti-melanoma and anti-lymphoma CTL. Moreover, TsF suppresses allogeneic CTL not only from C57BL/6 mice but also from C3H mice. Analysis of the biochemical and physiochemical character of TsF shows that TsF is stable for variance of pH and freeze and thawing, but unstable for heat in region of 100 degrees C. and in acetonitorile. It is also suggested that the molecular weight of TsF is in the vicinity of 12,000 daltons on the analysis in high performance liquid chromatography. F12 clone secretes other suppressive cytokine, TGF-beta and INF-gamma. However, TsF seems different from these suppressive cytokine, because anti-TGF-beta serum which blocks the suppressive function of TGF-beta 1 for CTL generation does not block TsF function. Moreover, recombinant INF-gamma does not suppress the generation of CTL.

Animals↗
PubMed1992

Identification and isolation of common and tissue-specific geranylgeranylated gamma subunits of guanine-nucleotide-binding regulatory proteins in various tissues.

Heterotrimeric guanine-nucleotide-binding regulatory proteins (G proteins) have been classified into several subtypes on the basis of the properties of their alpha subunits, though a notable multiplicity of gamma subunits has also been demonstrated. To investigate whether each subtype of alpha subunit is associated with a particular gamma subunit, various oligomeric G proteins, purified from bovine tissues, were subjected to gel electrophoresis in a Tricine buffer system. All G proteins examined were shown to have more than two kinds of gamma subunit. Of the brain G proteins, GoA, GoB, and Gi1 contain the same set of three gamma subunits, but Gi2 contains only two of these subunits. Lung Gi1 and Gi2 and spleen Gi2 and Gi3 had similar sets of two gamma subunits, one of which was distinct from the gamma subunits of brain G proteins. These observations indicate that each subtype of alpha subunit is associated with a variety of beta gamma subunits, and that the combinations differ among cells. For analyses of the structural diversity of the gamma subunits, beta gamma subunits were purified from the total G proteins of each tissue and subjected to reverse-phase HPLC under denaturing conditions, where none of the beta subunits were eluted from the column. Three distinct gamma subunits were isolated in this way from brain beta gamma subunits. In contrast, lung and spleen beta gamma subunits contained at least five gamma subunits, the elution positions and electrophoretic mobilities of which were indistinguishable between the two tissues. Among several gamma subunits, two subspecies appeared to be common to the three tissues. In fact, in each case, the partial amino acid sequence of the most abundant gamma subunit in each tissue was identical, and the sequences coincided exactly with that of 'gamma 6' [Robishaw, J. D., Kalman, V. K., Moomaw, C. R. & Slaughter, C. A. (1989) J. Biol. Chem. 264, 15758-15761]. Fast-atom-bombardment mass spectrometry analysis indicated that this abundant gamma subunit in lung and spleen was geranylgeranylated and carboxymethylated at the C-terminus, as was 'gamma 6' from brain. In addition to abundant gamma subunits, other tissue-specific gamma subunits were also shown to be geranylgeranylated by gas-chromatography-coupled mass spectrometry analysis of Raney nickel-treated gamma subunits. These results suggest that most gamma subunits associated with many different subtypes of alpha subunit are geranylgeranylated in a variety of tissues, with the single exception being the retina where the G protein transducin has a farnesylated gamma subunit.

Amino Acid Sequence↗
PubMed1992

Blockade of nitric oxide formation by N omega-nitro-L-arginine mitigates ischemic brain edema and subsequent cerebral infarction in rats.

In order to investigate whether or not nitric oxide (NO) formation underlies the cellular mechanisms of ischemic brain damage, we examined the effects of N omega-nitro-L-arginine (L-NNA), a NO synthase inhibitor, on ischemic brain edema and subsequent infarction in rats with middle cerebral artery occlusion (MCAo). For this purpose, administrations of L-NNA (1 mg/kg, i.p.) to each animal were done at the time of 5 min, 3, 6 and 24 h after MCAo, respectively. It was shown from this study that L-NNA significantly mitigated ischemic cerebral edema, and histological examinations revealed that this compound markedly reduced infarction size that occurred following MCAo. These results strongly suggest that NO formation is at least partly involved in the pathogenetic mechanisms of ischemic brain edema and subsequent cerebral infarction.

Animals↗
PubMed1992

Nonsense mutation of glucokinase gene in late-onset non-insulin-dependent diabetes mellitus.

A nonsense mutation at codon 186 in exon 5 of the gene for glucokinase, an enzyme important for glucose-induced insulin secretion, was identified in a Japanese patient with late-onset non-insulin-dependent diabetes mellitus (NIDDM). All affected members of her family were heterozygous for the mutation and had late-onset NIDDM or impaired glucose tolerance, whereas unaffected members showed normal glucose tolerance. The early insulin response to oral glucose was impaired in affected relatives, but was normal in those unaffected. These findings suggest that the glucokinase mutation raises the set-point of pancreatic beta cells for glucose-induced insulin secretion, leading to abnormal glucose tolerance in some patients with late-onset NIDDM.

Adolescent↗
PubMed1992

Characterization of GLUT3 protein expressed in Chinese hamster ovary cells.

We have expressed GLUT3 protein, an isoform of a facilitative glucose transporter, in Chinese hamster ovary cells by transfection of its cDNA using an expression vector. The expressed GLUT3 protein was detected by Western-blot analysis as a broad band of 45-65 kDa, indicating intensive glycosylation of the protein. The expressed GLUT3 protein was observed, by immunofluorescence staining, to be located mainly at the plasma membrane, and its expression was associated with a marked increase in glucose-transport activity. Kinetic analysis revealed that the Km value of GLUT3 protein for 3-O-methylglucose uptake was approx. 35% of that of GLUT1 protein, whereas the Km value of GLUT3 protein for 2-deoxy-D-glucose uptake was very similar to that of GLUT1 protein. The Vmax. value of GLUT3 protein for 3-O-methylglucose and 2-deoxyglucose uptake was approx. 20-50% of that of GLUT1 protein. GLUT3 protein was well photolabelled with [3H]cytochalasin B or a mannose derivative, 2-N-4-[3H](1-azi-2,2,2-trifluoroethyl)benzoyl-1,3-bis-(D-mannos -4-yloxy)-2- propylamine. Thus GLUT3 protein has very similar characteristics to GLUT1 protein including its subcellular localization, but exhibits lower Km and Vmax. values for 3-O-methylglucose uptake.

3-O-Methylglucose↗
PubMed1992

Replacement of intracellular C-terminal domain of GLUT1 glucose transporter with that of GLUT2 increases Vmax and Km of transport activity.

The intracellular C-terminal domain is diverse in size and amino acid sequence among facilitative glucose transporter isoforms. The characteristics of glucose transport are also divergent, and GLUT2 has far higher Km and Vmax values compared with GLUT1. To investigate the role of the intracellular C-terminal domain in glucose transport, we expressed in Chinese hamster ovary cells the mutated GLUT1 protein whose intracellular C-terminal domain was replaced with that of GLUT2 by means of engineering the chimeric cDNA. Cytochalasin B, for which GLUT2 protein has much lower affinity, bound to this chimeric protein in a fashion similar to GLUT1. In contrast, greater transport activity was observed in this chimeric glucose transporter compared with the wild-type GLUT1 at 10 mM 2-deoxy-D-glucose concentration. The kinetic studies on 2-deoxy-D-glucose uptake revealed a 3.8-fold increase in Km and a 4.3-fold increase in Vmax in this chimeric glucose transporter compared with the wild-type GLUT1. Thus, replacement of the intracellular C-terminal domain confers the GLUT2-like property on the glucose transporter. These results strongly suggest that the diversity of intracellular C-terminal domain contributes to the diversity of glucose transport characteristics among isoforms.

Amino Acid Sequence↗
PubMed1992

High levels of nervous system-specific proteins in cerebrospinal fluid in patients with early stage Creutzfeldt-Jakob disease.

Concentrations of several proteins that are characteristic of the nervous system were time-sequentially analyzed by radio- and enzyme-immunoassay in the cerebrospinal fluid (CSF) of patients with Creutzfeldt-Jakob disease (CJD). We found abnormally high levels of several proteins, such as neuron-specific enolase (NSE), S-100b protein, brain-type isozyme of creatine kinase (CK-BB) and alpha subunit of GTP binding protein G0 (G0 alpha) in the early stage of the disease. Generally, these protein levels were far higher in CJD patients than in normal controls and other neurological patients in the early stage before the typical clinical manifestations were evident. These levels increased to maxima when the disease activity was most prominent and returned to normal or mildly elevated levels in the terminal stage. The results imply that these protein levels can serve as biochemical markers for the presence of an active destructive process in CJD brain and provide us with a useful indicator for early diagnosis of CJD.

Brain↗
PubMed1992

Domains responsible for the differential targeting of glucose transporter isoforms.

Facilitative glucose transporter isoforms, GLUT1 and GLUT4, have different intracellular distributions despite their very similar structure. In insulin-responsive tissues such as adipose tissues and muscle, GLUT4 protein resides mainly in the intracellular region in a basal condition and is translocated to the plasma membrane upon stimulation of insulin. In contrast, GLUT1 protein was distributed about equally between plasma membranes and low density microsomal membranes in 3T3-L1 adipocytes. Furthermore, GLUT1 and GLUT4 were reported to be differentially targeted to the plasma membrane and intracellular region, respectively, when expressed in Chinese hamster ovary cells and HepG2 cells. To elucidate the differential intracellular targeting mechanisms, several chimeric glucose transporters in which portions of GLUT4 are replaced with corresponding portions of GLUT1 have been stably expressed in Chinese hamster ovary cells. Immunofluorescence and immunoelectron microscopy as well as measurement of glucose transport activity revealed that two domains of GLUT4, which are not the NH2- or COOH-terminal domain, determine its targeting to the intracellular vesicles. The first domain contains the consensus sequence of the leucine zipper structure, suggesting that a dimer-forming structure of the glucose transporter might be required for its proper targeting. The other domain contains 28 amino acids, nine of which are different between GLUT1 and GLUT4. Immunoelectron microscopy revealed that the chimeric transporters containing both of these two domains of GLUT1, only the first domain of GLUT1, and none of the domains, exhibited a different cellular distribution with approximately 65, 30, and 15% of the transporters apparently on the plasma membrane, respectively. The addition of insulin did not alter the apparent cellular distributions of these chimeric transporters. These domains would be specifically recognized by intracellular targeting mechanisms in Chinese hamster ovary cells.

Animals↗
PubMed1992

Possible prophylactic potential of HA1077, a Ca2+ channel antagonist and vasodilator, on chronic cerebral vasospasm.

We examined the possible prophylactic potential of HA1077, a calcium antagonist and vasodilator, on chronic cerebral vasospasm induced in a two-hemorrhage canine model, and also its effects on cerebral hemodynamics. The intravenous infusion of HA1077 3 mg/kg over 30 min twice daily (day 1-day 7) after the first intracisternal injection of 5 ml autologous blood significantly prevented the occurrence of chronic cerebral vasospasm. The mean diameter of the basilar arteries on day 7 was 66.1 +/- 1.6% (n = 7) of the baseline before the intracisternal injection of blood, compared to 54.2 +/- 1.6% (n = 9) of the baseline in the untreated group (P less than 0.01). Bolus intravenous administration of HA1077 (0.1 and 0.3 mg/kg) dose dependently increased local cerebral blood flow. Since HA1077 prevents the development of chronic cerebral vasospasm after subarachnoid hemorrhage and improves hemodynamic functions, as manifested by increases in local cerebral blood flow, further study is warranted regarding the possible clinical use of this drug.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Molecular cloning and characterization of the gene encoding mouse melanoma antigen by cDNA library transfection.

We have isolated a cDNA (H52) of 2.8-kb-long encoding an 80-kDa mouse melanoma Ag that is defined by a syngeneic anti-B16 melanoma mAb with an ability to block anti-melanoma cytotoxic T cell responses. H52 transfectants were brightly stained with the antibody, and the 80-kDa molecule was immunoprecipitated from the transfectants. Northern blot analysis showed that this transcript was detected in mouse melanoma cells of C57BL/6 and DBA/2 origin, C1300 A/J neuroblastoma, L cell (C3H) and EL-4 T lymphoma (C57BL/6), faintly in BW5147 (AKR) T lymphoma, but not in other tumors, such as S913 fibrosarcoma (C57BL/10), NIH3T3, 70 Z/3 pre-B lymphoma, and P3U1 plasmacytoma (BALB/c). Since the transcripts were not found in normal C57BL/6 tissues of fetus, newborn, and adult origin, the H52 expression is associated with transforming phenotypes. However, no tissue- or cell type-specific expression was observed. Nucleotide sequence analysis has clearly demonstrated that H52 cDNA encodes the full length of the env gene and long terminal repeat region of endogenous ecotropic murine leukemia provirus of AKV-type, which is defective in C57BL/6. The H52 envelope protein has several amino acid changes compared to those of AKV, one of which is in the env 14 peptide region preferentially associated with MHC molecule, suggesting the possible reason for the difference of antibody reactivity even in H52-positive tumors. We also demonstrate that CTL against H52 transfectant kills B16 melanoma. Thus, the above results are direct evidence that even the endogenous self molecule, when constitutively expressed, does act as a tumor Ag.

Amino Acid Sequence↗
PubMed1992

Effect of oligomers of ethylene glycol on thermotropic phase transition of dipalmitoylphosphatidylcholine multilamellar vesicles.

The effect of oligomers of ethylene glycol (EG) on thermotropic phase transitions of dipalmitoylglycerophosphatidylcholine multilamellar vesicles (DPPC-MLV) were investigated. Diethylene glycol (di-EG) had a biphasic effect on transition temperature, reducing pre-transition temperature (Tp) at low concentrations but increasing main transition temperature (Tm) and extinguishing pre-transition at high concentration. Results of the X-ray diffraction method and the excimer method indicated that di-EG induced interdigitated gel phase (L beta 1 phase) in the DPPC membranes at high concentration. Phase diagram of temperature-di-EG concentration for DPPC-MLV was determined by use of X-ray diffraction and differential scanning calorimetry, which was similar to that of temperature-EG concentration. The minimum concentration of di-EG where L beta 1 phase was induced was 42%(w/v), which was larger than that of EG (30%(w/v)). On the other hand, in the presence of triethylene glycol (tri-EG), Tm and Tp increased with an increased in tri-EG concentration, as well as poly(ethylene glycol). These differences, between the effects of di-EG and those of tri-EG, might be due to the differences of their sizes.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1992

Identification of 7 alpha-hydroxy-3-oxo-4-cholestenoic acid in chronic subdural hematoma.

We detected a novel kind of bile acid in the content of chronic subdural hematoma. This substance was specifically found in chronic subdural hematoma, and not in subdural hygroma, which is pathologically similar except for the lack of capsular membrane. The compound was identified as 7 alpha-hydroxy-3-oxo-4-cholestenoic acid by high performance liquid chromatography, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectrometry. The structure was confirmed by the comparison with the chemically synthesized compound. The average contents in chronic subdural hematoma were 658.09 +/- 137.53 ng/ml, while those in normal human plasma were 126.27 +/- 17.73 ng/ml. It was not detected in normal cerebrospinal fluid. The higher level in chronic subdural hematoma than human plasma strongly suggests the local, extrahepatic production of this type of C27 bile acids.

Bile Acids and Salts↗
PubMed1992

The oligosaccharides in a recombinant hepatitis B virus surface antigen (HBsAg) carrying the pre-S2 region derived from yeast.

The N- and O-linked oligosaccharides in a yeast-derived HBsAg M protein (pre-S2 + S) were analyzed. Two major structures of the N-linked oligosaccharides bound to residue Asn4 were determined to be high-mannose type oligosaccharides, Man7GlcNAc2 and Man8GlcNAc2, by two-dimensional sugar mapping of the corresponding pyridylamino oligosaccharides. Peptide mapping of the M protein, sequence analysis of the glycopeptides after beta-elimination under reducing conditions and sugar-composition analysis revealed that the O-linked oligosaccharides were composed solely of mannose and bound to residue Ser5, Thr6, Thr7, Ser27, Ser28, Ser29 and Thr31 in the pre-S2 region.

Amino Acid Sequence↗