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Biomedical subjects

Y Taniguchi

Publications and source records attributed to Y Taniguchi.

At least 289 records · Page 16Linked to original sources
PubMed1995

Physical interaction between a novel domain of the receptor Notch and the transcription factor RBP-J kappa/Su(H).

BACKGROUND: The mammalian transcription factor RBP-J kappa binds to the DNA sequence motif CGTGGGAA and is involved in the regulation of gene expression; for example, it plays a part in the transactivation of viral and cellular genes by Epstein-Barr virus nuclear antigen-2. The Drosophila homologue of RBP-J kappa is the product of the Suppressor of Hairless (Su(H)) gene. Su(H) is a neurogenic gene that acts downstream of Notch, which encodes a cell-surface receptor. Furthermore, in the mouse, the phenotypes of homozygous mutant Notch1 embryos are very similar to those of homozygous mutant RBP-J kappa embryos. Recent studies, using the yeast two-hybrid system, have led to the suggestion that the CDC10/ankyrin-like repeats of the Drosophila Notch protein interact with the Su(H) protein. RESULTS: We searched for proteins that interact with mouse RBP-J kappa using the yeast two-hybrid system, and in this way identified a short intracellular region (mRAM23) of the mouse Notch1 protein that lacks any known sequence motif. In vitro interaction studies, using proteins fused to glutathione-S-transferase, showed that RBP-J kappa and Su(H) bind directly to the RAM23 regions of mouse Notch1 and Drosophila Notch, respectively. Immunoprecipitation analysis showed that RBP-J kappa and the mRAM23 region of mouse Notch1 also interact in vivo. Further studies, including site-directed mutagenesis experiments, narrowed down the region of mouse Notch1 that interacts with RBP-J kappa. The results indicate that this region is less than 50 amino-acid residues in length, and lies immediately downstream of the transmembrane region. CONCLUSIONS: We show that the transcription factor RBP-J kappa/Su(H) interacts directly with a novel intracellular domain of the cell-surface receptor Notch. RBP-J kappa/Su(H) does not appear to interact with Notch via the CDC10/ankyrin repeats implicated in previous studies.

Amino Acid Sequence↗
PubMed1995

Molecular cloning and expression of megakaryocyte potentiating factor cDNA.

The human megakaryocyte potentiating factor (hMPF) has been previously purified from a culture supernatant of human pancreatic cancer cells HPC-Y5 (Yamaguchi, N., Hattori, K., Oh-eda, M., Kojima, T., Imai, N., and Ochi, N. (1994) J. Biol. Chem. 269, 805-808). We have now isolated hMPF cDNA from a HPC-Y5 cDNA library using polymerase chain reaction and plaque hybridization methods. The hMPF cDNA encodes a polypeptide consisting of 622 amino acids, including a signal peptide of 33 amino acids, and with a deduced molecular mass of 68 kDa, although HPC-Y5 cells secrete a 33-kDa form of hMPF. Human MPF does not show any significant homology with other previously described sequences. The cDNA was expressed in COS-7 and Chinese hamster ovary (CHO) cells, and megakaryocyte potentiating activity was detected in their culture supernatant. The COS-7 cells secreted only a 33-kDa recombinant hMPF, whereas an additional 30-kDa form was detected in the culture medium of CHO cells. The 33-kDa rhMPF purified from CHO cells showed megakaryocyte potentiating activity, but not the purified 30-kDa rhMPF. The difference in structure and activity between the 33- and 30-kDa forms of hMPF was ascribed to the existence in the 33-kDa form of the C-terminal 25 amino acid residues.

Amino Acid Sequence↗
PubMed1995

Multiple metastases of mammary carcinoma cell lines isolated from feral mouse.

Two established cell lines (JYG-A and B) isolated from mammary carcinoma tissues of M. m. musculus Sub-Jyg (a chinese wild mouse) showed multiple metastasis in the lung (100%), liver (40-60%), kidney (40-80%), lymph node (20-60%) and other organs of the nude mice inoculated with these cells subcutaneously or intravenously. In addition, 100% brain metastasis or infiltration was observed only when inoculated with JYG-B cells intravenously.

Animals↗
PubMed1995

Overexpression of the HOX4A (HOXD3) homeobox gene in human erythroleukemia HEL cells results in altered adhesive properties.

We previously isolated the human homeobox gene HOX4A (HOXD3) on chromosome 2 from a human genomic library and determined its nucleotide sequence. In the present study, expression of the HOX4A gene was investigated in human hematopoietic cell lines. Reverse transcriptase-mediated polymerase chain reaction analysis showed that the HOX4A gene was expressed in erythroleukemia HEL and K562 cells but not in promyelocytic leukemia HL-60 cells. To study the role of the HOX4A gene in erythropoiesis, expression vectors containing the HOX4A gene in the sense or antisense orientation were introduced into HEL cells. The sense transfectants overexpressing the HOX4A gene formed aggregates, which were composed of densely associated cells adhering to tissue-culture dishes, whereas the parental HEL cells and antisense transfectants adhered poorly to the dishes. Furthermore, the sense transfectants overexpressing the HOX4A gene attached more efficiently to fibronectin and collagen than did the antisense transfectants and parental HEL cells. Northern blot analysis showed that integrin beta 3 mRNA levels were significantly increased in the HEL cells overexpressing the HOX4A gene, whereas the integrin beta 1 and alpha IIb mRNA levels did not show a distinct correlation with HOX4A mRNA levels. Fluorescence-activated cell sorting analysis showed that the sense transfectants overexpressing the HOX4A gene expressed increased levels of integrin alpha IIb beta 3 (GP IIb-IIIa) complex as compared with the parental HEL cells and antisense transfectants. These results implicate the homeobox gene HOX4A in the regulation of cell adhesion processes.

Base Sequence↗
PubMed1995

Pressure- and thermally-induced reversible changes in the secondary structure of ribonuclease A studied by FT-IR spectroscopy.

Fourier transform infrared (FT-IR) spectroscopy combined with a resolution enhancement technique has been used to characterize pressure and thermal effects on the secondary structure of ribonuclease A. The experiments were performed at pD 7.0 with 50 mg/mL protein solution in D2O buffer. According to the observed changes in the amide I' band, secondary structure elements such as alpha-helices, beta-sheets, and turns are cooperatively disrupted by application of either pressures above 570 MPa at 30 degrees C or temperatures above 60 degrees C at 0.1 MPa. Pressure- and thermally-denatured ribonuclease A are fully unfolded and do not contain any residual secondary structures. Both the structural changes are intrinsically reversible, although the pressure-induced transition shows a hysteresis. It is found that nonnative turn structures are formed prior to the appearance of the native secondary structure in the folding from the pressure-unfolded state. The structural features upon the pressure-induced unfolding are additionally characterized by the interesting behavior of hydrogen-deuterium exchange at high pressure. Most of the backbone amide protons protected at atmospheric pressure, which are involved in the alpha-helices and beta-sheet, are exchanged with solvent deuterons in the pressure range where the two secondary structural elements are virtually identified as intact. There is a possibility that, for ribonuclease A, application of high pressure up to 570 MPa induces such a partially unfolded state as has native-like secondary structure but permits solvent to be highly accessible to the internal regions.

Animals↗
PubMed1995

Structure of the mouse thioredoxin-encoding gene and its processed pseudogene.

Thioredoxins (TXN) are small proteins with various biological functions, such as redox regulation, found in many species including bacteria, plants and animals. We previously reported the isolation of the TXN-encoding cDNAs from human and mouse. In order to elucidate the functions of the mammalian TXN system, we planned to generate Txn knockout mice, and cloned the genomic DNA fragments using the Txn cDNA as a probe. The Txn gene extends over 12 kb and consists of five exons separated by four introns. Detailed Southern analyses revealed that the mouse genome contains only one active Txn gene and one processed pseudogene (Txn-ps1), in contrast to some species which have families of active TXN-encoding genes. These findings should help to understand Txn itself, and provide a basis for transgenic experiments by gene targeting.

Amino Acid Sequence↗
PubMed1995

Lower-extremity venous stasis during laparoscopic cholecystectomy as assessed using color Doppler ultrasound.

Lower-extremity venous stasis during laparoscopic cholecystectomy was evaluated in 16 patients by monitoring the blood velocity in the femoral vein and the femoral vein size (cross-sectional area) using color Doppler ultrasonography. The blood velocity in the femoral vein decreased significantly after the start of 10-mmHg abdominal insufflation in the supine position. When the patients were placed in a reverse Trendelenburg position during 10-mmHg insufflation, blood velocity in the femoral vein further decreased. However, velocity returned to the baseline after deflation. The cross-sectional area of the femoral vein was significantly elevated after the start of 10 mm Hg insufflation in the supine position. When patients were placed in the reverse Trendelenburg position during 10-mmHg insufflation, this parameter was further elevated, but returned to the baseline soon after deflation. These results indicate that femoral vein stasis during laparoscopic cholecystectomy can be minimized by reducing the pressure of abdominal insufflation and avoiding elevation of the patient's head as much as possible.

Blood Flow Velocity↗
PubMed1995

Effects of Na(+)-H+ exchange blocker amiloride on left ventricular remodeling after anterior myocardial infarction in rats.

We investigated the effects of amiloride, a Na(+)-H+ exchange blocker, on ventricular remodeling in an infarcted rat model. In the amiloride group, the left descending coronary artery was ligated and rats were given amiloride (1 mg/kg/day, n = 11) in their drinking water for 4 weeks. In the control group, rats were given water for 4 weeks (n = 8) after myocardial infarction. The rats were killed on day 28. Both the ratio of heart weight to body weight and that of left ventricular weight to body weight were significantly less in the amiloride group (p < 0.05). The diameter of a myocardial fiber in the region adjacent to the operated area was significantly reduced in the amiloride group compared with the control group (p < 0.05). Left ventricular cavity dimension was significantly smaller in the amiloride group than that in control group (p < 0.05). Our findings suggest that amiloride prevents ventricular remodeling after myocardial infarction.

Amiloride↗
PubMed1995

Proliferation of pituitary corticotrophs following adrenalectomy as revealed by immunohistochemistry combined with bromodeoxyuridine-labeling.

Proliferation of corticotrophs following adrenalectomy (ADX) was studied by a combination of bromodeoxyuridine (BrdU)-labeling and immunohistochemistry. Rats were adrenalectomized, allowed to survive for 1, 3, 7, and 14 days and given 100 mg/kg body wt BrdU 3 h before sacrifice. BrdU and adrenocorticotropic hormone (ACTH) were detected in the same sections of the anterior pituitary using double-labeling immunohistochemistry. BrdU-labeled cells in the pituitary showed a tendency to increase until 1 week after ADX and slightly decreased at 2 weeks. Corticotrophs were increased to about 1.5 times of the control level 1-2 weeks after ADX. The number of cells double-labeled with both BrdU and ACTH increased markedly after ADX, suggesting active mitosis of existing corticotrophs. On the other hand, the ratios of these double-stained cells to all BrdU-labeled cells and to all corticotrophs were 5-7% and 0.9-1.3%, respectively, even after ADX, suggesting that the majority of corticotrophs which were increased after ADX were recruited from some other type of immature cells. The extent to which the two mechanisms are involved in hyperplasia of corticotrophs after ADX remains to be elucidated.

Adrenalectomy↗
PubMed1995

Influence of temperature and relative humidity on early bond strengths to dentine.

The effect of temperature and relative humidity (RH) on the early tensile bond strengths to bovine dentine of two bonding systems (Liner Bond System, and Scotchbond Multi-purpose), and an experimental system (KB-110) were tested. Two environmental conditions, room temperature (23 degrees C/50% RH) and oral temperature (30 degrees C/80% RH), were used in a controlled temperature and humidity chamber. Bond strengths were recorded immediately after, 10 min and 24 h following light curing. The tensile bond strengths did not vary between the two test conditions, but the mode of fracture was observed to change. The 30 degrees C/80% RH condition exhibited a slightly greater degree of adhesive type failures compared with the 23 degrees C/50% RH group. This was particularly so for the experimental system, indicating that different bonding systems may be more or less sensitive to changes in RH and temperature. Failures occurred partially or totally within the resin composite at the early test times, and it was concluded that the bond strengths of the systems tested tended to exceed the early cohesive strengths of the resin composite.

Adhesiveness↗
PubMed1995

Femoral vein stasis during laparoscopic cholecystectomy: effects of graded elastic compression leg bandages in preventing thrombus formation.

Venous stasis of the legs during laparoscopic cholecystectomy was compared between patients without graded compression leg bandages (Group 1; n = 12) and patients with such bandages (Group 2; n = 12) by measuring mean blood flow velocity and cross-sectional area of the femoral vein using a color Doppler ultrasonography. In Group 1, when velocity and area were measured in the supine position, a significant decrease in velocity (p < .05) and a significant increase in area (p < .05) occurred after abdominal insufflation to 10 mm Hg. These changes were greater during abdominal insufflation in the reverse Trendelenburg position than during abdominal insufflation in the supine position. In Group 2, flow velocity was significantly higher (p < .05) before abdominal insufflation as compared with Group 1. After abdominal insufflation to 10 mm Hg and a postural change, velocity significantly decreased (p < .05) and area significantly increased (p < .05) in Group 2, similar to the results in Group 1. During abdominal insufflation at 5 mm Hg or lower, the use of the graded compression bandage was found to be useful for preventing femoral vein stasis. During abdominal insufflation at 10 mm Hg or in the reverse Trendelenburg position, the bandage did not prevent femoral vein stasis.

Bandages↗
PubMed1995

Carbohydrate structures of the glycoprotein allergen Cry j I from Japanese cedar (Cryptomeria japonica) pollen.

The glycoprotein allergen Cry j I from Japanese cedar (Cryptomeria japonica) pollen was treated with pepsin and glycopeptidase A to release asparagine-linked oligosaccharides. The reducing ends of the oligosaccharides were aminated with the fluorescent reagent 2-aminopyridine. The oligosaccharide derivatives were purified by gel permeation chromatography and reversed-phase HPLC. Their structures were determined by sequential exoglycosidase digestion and 500 MHz 1H-NMR spectroscopy. Four oligosaccharide structures, A, B, C, and D, were identified as the xylose-containing complex-type. They were present at a molar ratio of 8:1:6:1. By amino acid sequence analyses of the tryptic peptides, Asn-170 and Asn-333 of Cry j I were found to carry asparagine-linked oligosaccharides. [formula: see text]

Allergens↗
PubMed1995

Efficacy of lansoprazole in eradication of Helicobacter pylori.

Fifty-eight Helicobacter pylori-positive ulcer patients received omeprazole 20 mg (n = 15), or lansoprazole 30 mg (n = 23), lansoprazole 60 mg (n = 13), or E3810 20 mg (n = 7) q.d. Another 63 H. pylori-positive ulcer patients received lansoprazole and clarithromycin for 2 weeks. Patients received lansoprazole 30 mg and clarithromycin 400 mg (group 1, n = 22), lansoprazole 30 mg and clarithromycin 800 mg (group 2, n = 12), or lansoprazole 60 mg and clarithromycin 800 mg (group 3, n = 29). Neither proton pump inhibitor (PPI) was capable of eradication by monotherapy, but the clearance rates in the lansoprazole group were 60.9 and 69.2%, which were higher than those for omeprazole (p < 0.05). In the dual therapy, eradication rates were 50, 50, and 72.4% in groups 1, 2, and 3, respectively. Minor side effects were observed in one case each in groups 1 and 3. Lansoprazole monotherapy proved more efficacious than omeprazole monotherapy, but it was unable to eradicate H. pylori. Dual therapy with lansoprazole 60 mg and clarithromycin 800 mg was an efficacious and safe regimen for H. pylori eradication in this study.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Immunoglobulins specific to mosquito salivary gland proteins in the sera of persons with common or hypersensitive reactions to mosquito bites.

Using the immunoblot technique, we analyzed the quality and quantity of IgG, IgG4, and IgE specific to mosquito salivary gland (hereafter abbreviate as SG) components of Aedes albopictus in the sera of volunteers with common reactions and of 3 patients with severe reactions. In the volunteers with delayed reactions only or with both delayed and immediate reactions, IgG against SG components of A. albopictus formed several faint or moderately stained bands. Those with immediate reactions showed several intense bands and many other weak bands. In volunteers, who had been bitten by Aedes sp. frequently but had no skin reaction, and in severe cases, many intense IgG bands were observed. IgG4 bound to SG components were found in the sera of the common reaction group at the levels of 24 and 48 kD, but, in one severe case, no bands were observed, although the total IgG was very high. IgE levels specific to SG components were much higher in severe cases than in the volunteers. These results indicate that high titers of specific IgG and IgE and lack of IgG4 for particular components of SG may lead to severe allergic reactions in severe cases. Immunoblotting analysis of the antibodies also verified the possibility of developing in vitro tests to identify causative species of the mosquito for severe cases.

Adult↗
PubMed1995

Sensitivity to two major allergens (Cry j I and Cry j II) in patients with Japanese cedar (Cryptomeria japonica) pollinosis.

BACKGROUND: Japanese cedar (Cryptmeria japonica: CJ) pollinosis is one of the most important allergic diseases in Japan. Recently, the second major allergen (Cry j II) was isolated from CJ pollen. There have been no prevalence studies of sensitivity to Cry j I and Cry j II among a large number of patients with pollinosis. OBJECTIVE: This study was conducted to evaluate the prevalence of sensitivity to Cry j I and Cry j II. We measured specific IgE antibodies to these allergens in the sera of 145 patients. Furthermore, comparison of the sensitivity to Cry j I and Cry j II was examined by the histamine release assay. METHODS: Specific IgE antibodies to Cry j I and Cry j II were assayed by a fluorometric ELISA. Allergen-specific histamine release was measured by a radioimmunoassay kit. RESULTS: More than 90% of 145 patients had specific IgE antibodies to both allergens, the remainder had specific IgE to either one or the other. There were seasonal changes in the level of specific IgE. The changes in the levels of anti-Cry j II IgE antibodies were parallel to those of anti-Cry j I IgE. The histamine release assay with leucocytes from the patients demonstrated that the allergenic potency of the two allergens is almost the same. CONCLUSION: Cry j II is an as important a major allergen as Cry j I.

Adult↗
PubMed1995

Cry j 2, a major allergen of Japanese cedar pollen, shows polymethylgalacturonase activity.

We examined Cry j 2, a major allergen of Japanese cedar (Cryptomeria japonica) pollen, for polygalacturonase enzyme activity, since a nucleotide sequence of cDNA of Cry j 2 showed a significant homology with that of tomato polygalacturonase. Polygalacturonase is well known to depolymerize preferentially polygalacturonic acid (PGA) by hydrolysis. However, Cry j 2 did not act on PGA, but was found to depolymerize pectin and methylesterified PGA in a dose-dependent manner. The substrate specificity of Cry j 2 was different from that of polygalacturonase derived from Aspergillus niger. The depolymerizing activity of Cry j 2 reached a maximum at 50%-60% of methylesterification of PGA. In contrast, polygalacturonase showed its maximum activity of PGA, and the activity decreased as the degree of methylesterification increased. Interestingly, the pectin-depolymerizing activity of Cry j 2 was due to a hydrolysis, but not a lyase, activity which splits the glycosidic bonds by beta-elimination, since no unsaturated uronides were found by measurement of absorbance at 235 nm in the reaction mixture. The enzyme activity was markedly inhibited by anti-Cry j 2 antibodies. These results indicate that Cry j 2 probably has polymethylgalacturonase enzyme activity, as postulated by von Neukom in 1963, although existence of this activity has not yet been proven.

Allergens↗
PubMed1995

Cry j I, a major allergen of Japanese cedar pollen, has pectate lyase enzyme activity.

In the course of analyzing the partial amino acid sequences of Cry j I, a major allergen of Japanese cedar (Cryptomeria japonica) pollen, we found a peptide fragment which has a significant homology to some pectate lyase isozymes secreted by plant pathogenic bacteria. Therefore, we investigated whether Cry j I has pectate lyase activity. Cry j I reacted with polygalacturonic acid, resulting in the release of unsaturated uronide products. The optimum temperature and pH for the reaction were 60-70 degrees C and pH 10. The enzymatic reaction had an absolute Ca2+ ion requirement. These characteristics were very compatible with the character of the pectate lyase isozymes reported previously. These results clearly show that Cry j I has pectate lyase activity.

Allergens↗