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Biomedical subjects

T Taguchi

Publications and source records attributed to T Taguchi.

At least 343 records · Page 19Linked to original sources
PubMed1996

Molecular cloning of the cDNA and chromosome localization of the gene for human ubiquitin-conjugating enzyme 9.

We report a novel human gene whose product specifically associates with the negative regulatory domain of the Wilms' tumor gene product (WT1) in a yeast two-hybrid screen and with WT1 in immunoprecipitation and glutathione S-transferase (GST) capture assays. The gene encodes a 17-kDa protein that has 56% amino acid sequence identity with yeast ubiquitin-conjugating enzyme (yUBC) 9, a protein required for cell cycle progression in yeast, and significant identity with other subfamilies of ubiquitin-conjugating enzymes. The human gene fully complements yeast that have a temperature-sensitive yUBC9 gene mutation to fully restore normal growth, indicating that we have cloned a functionally conserved human (h) homolog of yUBC9. Transcripts of hUBC9 of 4.4 kilobases (kb), 2.8 kb, and 1.3 kb were found in all human tissues tested. A single copy of the hUBC9 gene was found and localized to human chromosome 16p13.3. We conclude that hUBC9 retains striking structural and functional conservation with yUBC9 and suggest a possible link of the ubiquitin/proteosome proteolytic pathway and the WT1 transcriptional repressor system.

Amino Acid Sequence↗
PubMed1996

Detection of aneuploidy in interphase nuclei from non-small cell lung carcinomas by fluorescence in situ hybridization using chromosome-specific repetitive DNA probes.

Interphase fluorescence in situ hybridization (FISH) is particularly useful for detecting chromosome changes in tumors exhibiting a low mitotic index, as is the case in many human non-small cell lung carcinomas (NSCLCs). A panel of centromeric DNA probes specific for the autosomes 6, 7, 8, 9, 12, 17, and 18 was used to analyze 17 primary NSCLCs. Evidence for aneuploidy was obtained in all specimens. Gain of part or all of chromosome 7 was especially prominent, occurring in a large population of cells in each of 14 tumors (82%). Extra centromeric copies of chromosomes 6, 12, and 17 were also common, being observed in 9 to 11 cases each. Gain of chromosome 9 was infrequent (three tumors). In two cases, most of the nuclei had only a single chromosome 9 fluorescent signal. Karyotypic findings were available for six cases and were generally consistent with the FISH data. Both methods revealed considerable heterogeneity within individual tumors. NSCLC specimens from 26 males were assayed with a Y-specific centromeric sequence; loss of the Y was observed in 13 cases (50%). These investigations demonstrate the feasibility of interphase FISH for the successful analysis of numerical chromosome changes in NSCLCs.

Aneuploidy↗
PubMed1996

Occurrence and structural analysis of highly sulfated multiantennary N-linked glycan chains derived from a fertilization-associated carbohydrate-rich glycoprotein in unfertilized eggs of Tribolodon hakonensis.

This study represents the first detailed investigation of the nature of highly sulfated (keratan-sulfate-like) complex-type asparagine-linked glycans having a tetraantennary core structure and shows the effectiveness of fast-atom-bombardment mass spectrometric (FAB-MS) methods incorporating derivatization and mild methanolysis for analyzing such complex types of sulfated glycans. The structure of the N-glycan chains was unambiguously established by a combination of compositional analysis, methylation analysis, mild methanolysis for desulfation, hydrazinolysis/nitrous acid deamination, enzymatic (endo-beta-galactosidase and peptide:N-glycosidase F) digestions, and instrumental analyses (1H-NMR spectroscopy and FAB-MS) which revealed the novel repeating sulfated carbohydrate sequences, +/- Gal beta 1-->4Gal beta 1[-->(HSO3-->6)GlcNAc beta 1-->3(+/- Gal beta 1-->4)Gal beta 1]n--> (see Structure I; p + q + r + s approximately 14). This sequence is unique in: (a) the skeletal structure is similar to that of keratan sulfate but is completely devoid of 6-O-sulfated Gal residues and (b) the presence of branched Gal residues in the sequence -->4GlcNAc beta 1-->3(Gal beta 1-->4)Gal beta 1-->. [formula: see text]

Animals↗
PubMed1996

Isolation of cDNA and genomic clones of a human Ras-related GTP-binding protein gene and its chromosomal localization to the long arm of chromosome 7, 7q36.

A Ras-related GTP-binding protein cDNA has been isolated from a human skin fibroblast cDNA library using a genomic subclone derived from a YAC clone as a probe. The polypeptide, consisting of 184 amino acids deduced from nucleotide sequences, contains five repeats of the Ras-related GTP-binding region and is highly homologous to the rat RHEB (Ras homologue enriched in brain) gene, which encodes a Ras-related growth factor- and synaptic activity-regulated protein, with 98.9% amino acid identity. Therefore, it is suggested to be a human homologue of the rat RHEB protein, and we have designated it human RHEB. Using fluorescence in situ hybridization, we concluded that this human RHEB gene was localized to band q36 on chromosome 7. Considering the chromosomal localization as well as the potential function of this protein, it will be very important to investigate whether it may play a role in the etiopathogenesis of holoprosencephaly type 3 or hereditary sacral agenesis, in which the disease susceptible locus is linked to the microsatellite marker, D7S22, in this chromosomal region, 7q36.

Amino Acid Sequence↗
PubMed1996

Cloning of a putative ligand for the T1/ST2 receptor.

T1/ST2 is a receptor-like molecule homologous to the type I interleukin-1 receptor. Despite this sequence similarity, we have been unable to demonstrate binding of T1/ST2 to any of the three interleukin-1 species. In searching for a ligand for T1/ST2, we have cloned a cell surface protein to which it binds. This protein is unable to initiate signal transduction by the T1/ST2 receptor in several in vitro assays.

3T3 Cells↗
PubMed1996

Two modes of activity-dependent synaptogenesis of cerebral neurons in vitro.

Effects of transduction activity and transmission activity on synaptogenesis of chick cerebral neurones in dissociated cell culture were studied electrophysiologically using two blockers for these activities, tetrodotoxin (TTX) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), respectively. CNQX inhibited the increase of evoked EPSCs more effectively than TTX, whereas both blockers similarly reduced the increase of miniature EPSCs (Minis). These data indicated that not only transduction-dependent transmission activity but also transduction-independent spontaneous activity regulate the synaptic efficiency. These two activities are suggested to change the quantal amplitude and the number of synaptic sites, respectively.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1996

Neuronal and muscular functions as parameters of graft viability in small bowel transplantation.

The physiological properties of neurons and smooth muscles were studied after cold preservation of a rat small intestinal graft, in order to evaluate the graft viability before reperfusion. A 25-cm jejunal graft was harvested from a Lewis rat and stored in University of Wisconsin solution for 0, 12, 24, 48, and 72 hr at 4 degrees C (n = 8, each group). The intestinal samples were physiologically studied at the end of cold preservation. The positive rates of the specimens showing both biphasic nervous activities and spontaneous rhythmic activities were 100, 100, 88, 25, and 0% in 0-, 12-, 48-, and 72-hr preservation groups, respectively. The maximal contractions produced by acethylcholine chloride were 1.12 +/- 0.32, 0.63 +/- 0.22, 0.43 +/- 0.15, 0.52 +/- 0.32, and 0.27 +/- 0.13g for the 0-, 12-, 24-, 48-, and 72-hr preservation groups, respectively. The graft survivals after syngeneic transplantation (n = 6, each group) were 6 out of 6 (100%), 5 out of 6 (83%), 5 out of 6 (83%), 1 out of 6 (17%), and 0 out of 6 (0%) for the 0-, 12-, 24-, 48-, and 72-hr preservation groups, respectively. The graft survival correlated closely with the positive sample rates of the specimens, showing both biphasic nervous activities and spontaneous rhythmic activities. It only took about 1 hr and 20 min to complete the physiological examination of the graft, and thus, such an examination of the graft is considered to be both a simple and a reliable method for predicting graft viability before transplantation.

Animals↗
PubMed1996

Okadaic acid gives concentration-dependent reciprocal effects on the fluid phase endocytosis activated by Ca2+ and phorbol 12-myristate 13-acetate.

Incubation of a human fibrosarcoma cell line HT-1080 in increasing concentration of Ca2+ was found to enhance endocytic internalization of a fluid phase marker, horseradish peroxidase. At 16.8 mM Ca2+, generation of the effect required incubation for more than 45 min. The effect was reversed by removal of the excess ion for 30 min. Monitoring the intracellular concentration showed that the incubation induced a transient large Ca2+ influx followed by a recovery to 230 +/- 50 nM instead of the normal level of 83 +/- 5 nM. The activation was not inhibited by inhibitors of protein kinases nor a cAMP antagonist. In contrast, the effect was prevented by okadaic acid (OKA) at 100 nM without detectable effect on the basal activity. Fluid phase uptake by HT-1080 cells was also enhanced by phorbol 12-myristate 13-acetate (PMA). In contrast to the case with Ca2+, OKA at 100 nM did not prevent the PMA effect but further enhanced the endocytosis. The effect of OKA was concentration-dependent, as the reagent at 1 microM inhibited not only both the activation but also the basal activity. In Ca(2+)- or PMA-stimulated cells, FITC-dextran was delivered to endosomes that had been labeled with TRITC-transferrin. In contrast, following treatment with a combination of PMA and 100 mM OKA, fluid phase was internalized in vesicular compartments devoid of transferrin labeling. These results suggest that, through differential modifications of protein phosphorylation, endocytosis can be enhanced distinctively either by employing conventional receptor-bearing compartments or generating a new endosomal population.

Biological Transport↗
PubMed1996

A randomized trial comparing ftorafur alone with ftorafur plus tamoxifen in postoperative adjuvant therapy for breast cancer. Kinki Area Research Group for Postoperative Adjuvant Therapy for Breast Cancer.

A randomized study was performed in 35 centers in the Kinki area of Japan to determine the effectiveness of ftrorafur (FT) plus tamoxifen (TAM) compared with FT monotherapy in postoperative adjuvant therapy for breast cancer. Patients were randomized by the envelope method to receive either FT 600 mg/day or FT 600 mg/day plus TAM 20 mg/day orally for 1 year, starting on day 7 after mastectomy. Between April 1982 and January 1985, 628 patients were assigned to treatment with FT alone and 626 to treatment with FT + TAM. Of these, 571 (90.9%) and 539 (86.1%) patients, respectively, met the eligibility requirements for this study. There were no significant differences in major background factors between the two groups of eligible patients. Five-year survival rates were 91.4% for FT alone and 91.1% for FT+TAM (not significantly different). Five-year disease-free survival rates showed a tendency towards a better prognosis (P = 0.090) in the FT + TAM group, with observed rates of 83.0% for FT alone and 86.7% for FT + TAM. Stratified analysis showed that disease-free survival with FT + TAM is better than with FT alone for patients aged 50 years or more ( P = 0.048) and for patients with from one to three positive nodes (P = 0.064).

Adult↗
PubMed1996

Hepatocyte growth factor in nephronophthisis-medullary cystic disease complex.

A 13-year-old Japanese girl presented with severe anemia and renal dysfunction. The nephronophthisis-medullary cystic disease complex was diagnosed from the results of renal biopsy and a family study. Immunohistochemical detection of hepatocyte growth factor in the epithelial cells of dilated renal tubules suggested that it may have a role in the development of the tubular cystic changes which are characteristic of this disease.

Adolescent↗
PubMed1996

GTP-binding protein activation underlies LTP induction by mast cell degranulating peptide.

Mast cell degranulating peptide (MCD) induces long-term potentiation (LTP) in the CA1 region of the hippocampus. MCD has been shown to bind to a voltage-dependent A-type potassium channel with high-affinity (less than 1 nM). However, the concentration necessary to induce LTP is more than 500 nM, suggesting that some other functions of MCD are also fundamental to LTP induction. The concentration of MCD required for LTP induction was greatly reduced by preactivating G proteins. This fact suggests that G protein activation by MCD also plays an important role in LTP induction. MCD-binding proteins were purified from rat brain. G proteins were found to exist in a non-denatured state in this affinity-purified fraction. When reconstituted into a planar lipid bilayer membrane, a potassium-selective and voltage-dependent current could be observed. This channel was blocked by MCD at a high concentration equal to the effective concentration for G protein activation. Addition of GTP-gamma-S significantly blocked the reconstituted current. Thus, we identified a pathway for LTP induction by MCD in which high concentrations of MCD activate G protein which in turns leads to blocking of a potassium channel.

Adenosine Diphosphate Ribose↗
PubMed1996

Trapidil modifies mesangial cell proliferation and collagen accumulation in anti-thymocyte serum (ATS)-induced glomerulonephritis.

This study was designed to assess whether the glomerular mesangial-cell proliferation and the increased extracellular matrix (ECM) accumulation that occur in anti-thymocyte serum (ATS)-induced glomerulonephritis (GN) are affected by Trapidil, a potent antagonist for platelet-derived growth factor (PDGF). Fifteen male Wistar rats were divided into three groups. In group I, GN was induced by injecting a single dose of ATS. In group II, rats were given a single dose of ATS followed by daily treatment with Trapidil. In group III, the rats (controls) were treated with a single dose of phosphate buffered saline. All the rats were killed on the 10th day of the experiment. ATS induced marked mesangial cell proliferation (P < 0.01) in group I rats and Trapidil treatment (group II) significantly suppressed such proliferation (P < 0.01). Increased type III and IV collagen immunolabelling was observed in the expanded mesangial matrix in group I rats. In group II, immunolabelling for type III and IV collagen was much less than in group I. The study suggests that Trapidil therapy is effective in suppressing both mesangial cell proliferation and mesangial matrix expansion by reducing collagen accumulation.

Animals↗
PubMed1996

Energy metabolism and tissue blood flow as parameters for the assessment of graft viability in rat small bowel transplantation.

The assessment of small bowel graft viability by means of energy metabolism and tissue blood flow was investigated and compared with pathological findings. Syngeneic heterotopic small bowel transplantations were performed using male Lewis rats, which were divided into four groups according to the duration of cold preservation in University of Wisconsin (UW) solution; 6-, 12-, 24-, and 48-hour groups. The adenine nucleotide metabolism, the tissue blood flow, and the pathological profiles of the grafts were all compared among the groups. The adenosine triphosphate (ATP) levels at the end of cold storage and at 30 minutes after reperfusion, as well as the total adenine nucleotide (TAN) levels at the end of cold storage, before reperfusion, and at 30 minutes after reperfusion were significantly lower in the 48-hour group than those in the other groups, and the blood flow level at reperfusion was significantly lower in the 48-hour group than that in the others. Histological damage after reperfusion extended deep into the crypt layer in the 48-hour group but was confined to within villi in the other groups. These results suggest that the tissue ATP, TAN, and the blood flow levels are considered useful parameters for the assessment of small bowel graft viability.

Adenine Nucleotides↗
PubMed1996

The relationship between the adenine nucleotide metabolism and the conversion of the xanthine oxidase enzyme system in ischemia-reperfusion of the rat small intestine.

The time course of the energy metabolism after reperfusion, the relationship between the conversion of xanthine dehydrogenase to xanthine oxidase (D-to-O conversion) during ischemia, and the changes of the energy metabolism after reperfusion were studied using an ischemia-reperfusion model in the small intestine of the rat. The rat jejunum underwent an occlusion of the superior mesenteric artery and vein for either 30 minutes (group 1, n = 6) or 90 minutes (group 2, n = 6) with collateral interruption, and then it was reperfused. The contents of the adenine nucleotides in the small intestine of the rat were measured by high-performance liquid chromatography (HPLC) before ischemia, and 30, 60, and 90 minutes of ischemia, as well as 30, 60, 120, and 180 minutes after reperfusion. The recovery level of adenosine triphosphate (ATP) in group 1 (6.05 +/- 0.80 mumol/g dry weight) 30 minutes after reperfusion was significantly higher than that in group 2 (2.28 +/- 1.12 mumol/g dry weight) (P < .001). In addition, the ATP content after reperfusion in group 2 did not change from 30 to 180 minutes after reperfusion. The D-to-O conversion during ischemia in group 1 was not significantly greater than that before ischemia; however, that of group 2 did increase significantly during ischemia (P < .005). These results suggest that the tissue damage from ischemia-reperfusion injury after reperfusion under 90 minutes' ischemia is accomplished within the first 30 minutes after reperfusion. Therefore, the ATP level at 30 minutes after reperfusion may be useful for the evaluation of intestinal viability. Thus, the conversion of the xanthine oxidase enzyme system might play an important role in the expression of ischemia-reperfusion injury.

Adenine Nucleotides↗
PubMed1996

Long-term results of short segmental syngeneic small intestinal transplantation: comparison of jejunal and ileal grafts.

A short-segment intestinal graft is favorable to reduce the rate of rejection and the incidence of graft-versus-host disease in recipients of small intestine transplantation. To determine whether a jejunal or an ileal graft is preferable with respect to intestinal morphology and function, syngeneic two-step small intestinal transplantations were performed using male Lewis rats (RT1(1)). They were divided into two groups according to the small intestine donor site (group 1 received 10 cm of jejunum; group 2 received 10 cm of ileum). There was no significant difference in the survival rate or weight gain between the two groups. Nearly all the hematologic findings, serum nutritional parameters, and results of liver function tests were normal for both groups. The only difference was that the serum total bile acid level was significantly higher in group 2. Fifty weeks after transplantation, the graft mucosa showed normal architecture, with adaptive hyperplasia of villi and crypt noted through histological study. The villus height of group 1 was 595 +/- 64 microns (control, 452 +/- 67 microns); that of group 2 was 732 +/- 53 microns (control, 217 +/- 20 microns). The crypt depth of group 1 was 228 +/- 35 microns (control, 165 +/- 24 microns); that of group 2 was 320 +/- 19 microns (control, 102 +/- 19 microns). These compensatory changes were more pronounced in group 2. The authors conclude that, on the basis of long-term functional capacity, there was no significant difference between jejunal and ileal grafts, and that both segments were suitable for transplantation. However, the ileal graft was considered to be better with respect to morphological adaptation.

Animal Nutritional Physiological Phenomena↗