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Biomedical subjects

K Yagi

Publications and source records attributed to K Yagi.

At least 145 records · Page 8Linked to original sources
PubMed1999

Increase in thioredoxin activity of intestinal epithelial cells mediated by oxidative stress.

Hydrogen peroxide was cytotoxic to the small intestine epithelial cell line, IEC-6, as judged from an MTT assay and the release of lactate dehydrogenase. The glutathione S-transferase and thioredoxin reductase activities and SH content decreased dose-dependently with H2O2, but thioredoxin activity increased at low H2O2 concentrations. In addition, the increase in thioredoxin activity was time-dependent during the initial stages of oxidative stress. A reverse transcription-polymerase chain reaction (RT-PCR) amplification also showed that the mRNA content in IEC-6 cells increased time-dependently at 0.25 mM H2O2. These results indicate that cellular oxidative shock causes an increase in the activity of thioredoxin, which is involved in the defense mechanism against oxidative stress.

Animals↗
PubMed1999

Immobilization of tripeptide growth factor glycyl-L-histidyl-L-lysine on poly(vinylalcohol)-quarternized stilbazole (PVA-SbQ) and its use as a ligand for hepatocyte attachment.

A tripeptide growth factor, glycyl-L-histidyl-L-lysine (GHK), was immobilized on the surface of poly(vinylalcohol)-quarternized stilbazole (PVA-SbQ) gel. The photoreactive substance, 4-(3-trifluoromethylazirino)benzoyl-N-hydroxysuccinimide (TDBA-OSu), was employed to link the gel and ligand GHK. The density of immobilized GHK was 70 nmol/cm2. Isolated rat hepatocytes were inoculated on the GHK-immobilized PVA-SbQ gel and cultured for 5 d. About 24 h after inoculation, hepatocytes started to aggregate and formed multicellular spheroids while almost no cells attached to GHK-non-immobilized PVA-SbQ gel. The formed spheroids attached firmly to the surface of PVA-SbQ gel for 5 d. GHK was, thus, shown to be an effective ligand for hepatocyte attachment. Dodecamethylenediamine was used to extend the length between the gel surface and GHK. Extension of the length significantly increased the number of attached hepatocytes.

Animals↗
PubMed1999

Chemical control of Haematobia irritans with 0.5% topical ivermectin solution in cattle.

A field trial was conducted to evaluate the efficacy of a topical formulation of ivermectin administered at the dose of 500 micrograms/kg against horn flies (Haematobia irritans) in cattle. Eighty-eight cattle in four herds naturally exposed to horn flies were used in the trial. Replicates were formed of two herds. Within replicates, one herd was randomly allocated to the untreated control and the other to the ivermectin treatment group. Horn fly counts were taken on the treatment day (Day 0) and on Days 7, 14, 21, 28, and 35 post-treatment. There were no horn flies on any cattle in the treatment group, whereas all the control cattle were continuously infested by horn flies on each examination day.

Administration, Topical↗
PubMed1999

cDNA sequence of bovine thioredoxin.

In this paper, we report the cDNA sequence of bovine thioredoxin. We determined the full-length cDNA sequence of bovine thioredoxin by RT-PCR, 5'-RACE and 3'-RACE methods. Currently, the thioredoxin cDNA sequences of only five mammalian species (human, macaca, mouse, ovine and rat) are registered in the GenBank database. We performed sequence comparisons on the total cDNA sequence and the coding region, and produced a multialignment between the amino acid sequences of bovine and other mammalian thioredoxins. The amino acid sequences of thioredoxins are highly conserved among mammalian species, for example, only one difference exists between the amino acid sequences of bovine and ovine thioredoxin.

Animals↗
PubMed1999

cDNA sequence of bovine thioredoxin.

In this paper, we report the cDNA sequence of bovine thioredoxin. We determined the full-length cDNA sequence of bovine thioredoxin by RT-PCR, 5'-RACE and 3'-RACE methods. Currently, the thioredoxin cDNA sequences of only five mammalian species (human, macaca, mouse, ovine and rat) are registered in the GenBank database. We performed sequence comparisons on the total cDNA sequence and the coding region, and produced a multialignment between the amino acid sequences of bovine and other mammalian thioredoxins. The amino acid sequences of thioredoxins are highly conserved among mammalian species, for example, only one difference exists between the amino acid sequences of bovine and ovine thioredoxin.

Amino Acid Sequence↗
PubMed1999

[Analysis of outcome of free jejunal-autograft for head and neck reconstruction--postoperative complications and functional results of swallowing in 49 cases].

We evaluated postoperative results in 49 patients (39 men, 10 women) who underwent pharyngoesophageal reconstruction with free-jejunal autograft following total pharyngolaryngoesophagectomy in the Department of Otolaryngology, Hokkaido University School of Medicine from 1989 to 1997. Evaluation was performed regarding the following points: 1) postoperative complications, 2) factors that determine the functional results of swallowing, 3) relation between forms of jejunal anastomosis and swallowing. The primary malignancy site was hypopharynx (39), cervical esophagus (4), larynx (3), thyroid (2) and trachea (1), Reconstructions were made with free jejunal autograft alone in 45 cases and with free jejunum in combination with gastric pull-up in 4. In patients who underwent reconstruction with jejunum alone, the anastomosis of the jejunum to the pharynx was performed in side-to-end fashion in 22, end-to-end in 18 and rho-shaped in 4. In the 1 remaining case, we used jejunal-patch graft. Postoperative complications including minor or nongraft related, occurred in 24 of 49 (49.0%) patients. Among these, graft-related complications were graft failure in 1 (2.0%), fistula formation in 3 (6.1%) and graft stricture in 2 (4.0%). Re-operations were required in one case of graft failure and 2 of fistula formation. Consequently, the overall graft-survival rate was 98.0% (48/49). Therefore, we considered the method of reconstruction to be a reliable procedure with a high-success rate. The swallowing function after reconstructive surgery was studied in 35 patients who underwent side-to-end (18) and end-to-end (17) anastomosis of the jejunum to the pharynx. We indicated that appropriate tension in the jejunum was the most important factor for adequate swallowing function. The end-to-end group had a higher rate of taking normal diet compared with the side-to-end group. The rate of swallowing dysfunction was only 5.9% (1/17) in the end-to-end group. On the other hand, 4 of 18 (22.2%) cases in the side-to-end group were regarded as having poor swallowing function. As a result we considered the end-to-end proximal jejunal anastomosis to be the more desirable form.

Adult↗
PubMed1999

A strange calmodulin of yeast.

Calmodulin of Saccharomyces cerevisiae has different Ca2+ binding properties from other calmodulins. We previously reported that the maximum number of Ca2+ binding was 3 mol/mol and the fourth binding site was defective, which was different from 4 mol/mol for others. Their macroscopic dissociation constants suggested the cooperative three Ca2+ bindings rather than a pair of cooperative two Ca2+ bindings of ordinary calmodulin. Here we present evidence for yeast calmodulin showing the intramolecular close interaction between the N-terminal half domain and the C-terminal half domain, while the two domains of ordinary calmodulin are independent of each other. We will discuss the relationship of the shape and the shape change caused by the Ca2+ binding to the enzyme activation in yeast. The functional feature of calmodulin in yeast will also be considered, which might be different from the one of vertebrate calmodulin.

Animals↗
PubMed1999

Prognostic significance of clinical parameters and biological markers in patients with squamous cell carcinoma of the head and neck treated with concurrent chemoradiotherapy.

Concurrent chemoradiotherapy is reported to have a fair clinical outcome with organ preservation for patients with squamous cell carcinoma of the head and neck (SCCHN). The aim of this study was to determine whether biological markers are related to proliferative activity or apoptosis of tumor cells and whether clinical factors are associated with a clinical outcome in SCCHN patients treated with concurrent chemoradiotherapy. Immunostaining with antibodies specific for p53, bcl-2, bax, and MIB-1 was performed to evaluate expression of these proteins in formalin-fixed, paraffin-embedded specimens of 111 SCCHN patients treated with concurrent chemoradiotherapy (carboplatin, 100 mg/m2, four to six times every week; total radiation therapy dose of 40-65 Gy over 4-6.5 weeks). Multivariate analysis indicated that nodal status was a significant indicator of overall survival (OS; P = 0.001) and locoregional control (LRC; P = 0.002). In a univariate analysis, patients with a low MIB-1-positive index (< 40%) had better OS than those with a high MIB-1-positive index (> or = 40%; P = 0.013), although the difference was not statistically significant in a multivariate analysis (P = 0.060). Patients with bcl-2-positive tumors had better LRC than those with bcl-2-negative tumors, based on a multivariate analysis (P = 0.017). No statistically significant association was found between p53 or bax expression and clinical outcome. These results indicate that nodal status is the major prognostic factor in SCCHN patients treated with concurrent chemoradiotherapy. In addition, our findings suggest that bcl-2 positivity is associated with better LRC and that the proliferative activity of tumor cells might be prognostic for OS.

Antigens, Nuclear↗
PubMed1999

Recent epidemiologic trends in alveolar echinococcosis prevalence in humans and animals in Hokkaido.

We investigated chronological and geographical changes of alveolar echinococcosis (AE) prevalence in 14 administrative districts of Hokkaido based on the data of our epizootiologic and seroepidemiologic surveys. The results suggest that the chronological transitions of the enzootic state of AE in Hokkaido markedly reflect those of human AE prevalence, and that new prevalence of human AE has been emerging from central and western Hokkaido.

Animals↗
PubMed1999

Distribution of Helicobacter pylori in a Mongolian gerbil gastric ulcer model.

BACKGROUND AND PURPOSE: To the authors' knowledge, histopathologic changes associated with early H. pylori infection and ulceration have not been established. We examined presence of H. pylori infection in an acetic acid-induced gastric ulcer (AAU) model in Mongolian gerbils. METHODS: Sixty Mongolian gerbils were used as an AAU model, and another 60 gerbils were studied as a control (non-AAU) group. All animals were orally administered H. pylori, then were evaluated by use of histologic and bacteriologic examinations. RESULTS: Helicobacter pylori were scattered on the surface mucous gel layer and in the pyloric gland gastric were pits; inflammation seen at the early stages later extended to the mucosa of the fundic gland area. The organisms were predominantly observed in the AAU model, but findings were comparable to those in controls at 1, 3, 7, 14, 28, or 56 days. Evaluation with regard to viable bacterial numbers reflected the histologic aspects, that the pyloric gland area had more viable counts than did the fundic gland area. Carbohydrate composition of mucin differed between pyloric and fundic gland areas. These findings shed light on L-fucose related to the H. pylori adhesive factor abundant in mucin of the pyloric gland area. CONCLUSIONS: Findings for this ulcer model of Helicobacter pylori infection make it useful for the study of onset of infection and screening of anti-ulcer agents.

Acetic Acid↗
PubMed1999

[Effect of ondansetron hydrochloride injection and tablet against nausea and vomiting in lung cancer patients receiving carboplatin].

We investigated the efficacy of combination of ondansetron hydrochloride injection and tablet against nausea and vomiting in 22 lung cancer patients (total number of chemotherapy courses: 23) receiving chemotherapy of single-dose carboplatin (CBDCA) at a dose of 302.2 +/- 31.9 mg/m2. For suppressing emesis, the patients were given 4 mg of ondansetron injection on the day of CBDCA injection (Day 1), and 4 mg/day of ondansetron tablet for Days 2 to 5. The following results were obtained 5 days after the administration of carboplatin. 1) Control of nausea graded 'Good' or better counted for 95% or higher of all cases for each day of the chemotherapy. A complete nausea suppression rate was seen in 91.3%, 81.0%, 71.4%, 63.6% and 71.4% from Day 1 to Day 5, respectively. 2) Control of vomiting graded 'Major' control or better was achieved in 95% or more of all cases, for each day. The complete vomiting suppression rate observed from Day 1 to Day 5 was 91.3%, 78.3%, 65.2%, 69.6% and 91.3%, respectively. 3) Inhibitory effect on nausea and vomiting for each day of Days 1 to 5 graded as 'Effective' or better was shown in 90% or higher of all cases; based on overall judgement for Days 1 to 5, all cases were graded as 'Effective' or better. 4) The proportion of cases which was evaluated as 'Can eat most of the meal' was 88.0%, 73.9%, 50.7%, 50.7% and 65.2% from Days 1 to 5, respectively, against 95.7% prior to the start of chemotherapy. 5) No adverse drug reaction or abnormal clinical laboratory values were seen along with ondansetron. 6) In conclusion, combined treatment with ondansetron injection and tablet was considered clinically useful in control of nausea and vomiting during administration of carboplatin, and may also be useful for out-patient chemotherapy.

Adult↗
PubMed1998

Distinct effects of fatty acids on translocation of gamma- and epsilon-subspecies of protein kinase C.

Effects of fatty acids on translocation of the gamma- and epsilon-subspecies of protein kinase C (PKC) in living cells were investigated using their proteins fused with green fluorescent protein (GFP). gamma-PKC-GFP and epsilon-PKC-GFP predominated in the cytoplasm, but only a small amount of gamma-PKC-GFP was found in the nucleus. Except at a high concentration of linoleic acid, all the fatty acids examined induced the translocation of gamma-PKC-GFP from the cytoplasm to the plasma membrane within 30 s with a return to the cytoplasm in 3 min, but they had no effect on gamma-PKC-GFP in the nucleus. Arachidonic and linoleic acids induced slow translocation of epsilon-PKC-GFP from the cytoplasm to the perinuclear region, whereas the other fatty acids (except for palmitic acid) induced rapid translocation to the plasma membrane. The target site of the slower translocation of epsilon-PKC-GFP by arachidonic acid was identified as the Golgi network. The critical concentration of fatty acid that induced translocation varied among the 11 fatty acids tested. In general, a higher concentration was required to induce the translocation of epsilon-PKC-GFP than that of gamma-PKC-GFP, the exceptions being tridecanoic acid, linoleic acid, and arachidonic acid. Furthermore, arachidonic acid and the diacylglycerol analogue (DiC8) had synergistic effects on the translocation of gamma-PKC-GFP. Simultaneous application of arachidonic acid (25 MicroM) and DiC8 (10 microM) elicited a slow, irreversible translocation of gamma-PKC- GFP from the cytoplasm to the plasma membrane after rapid, reversible translocation, but a single application of arachidonic acid or DiC8 at the same concentration induced no translocation. These findings confirm the involvement of fatty acids in the translocation of gamma- and epsilon-PKC, and they also indicate that each subspecies has a specific targeting mechanism that depends on the extracellular signals and that a combination of intracellular activators alters the target site of PKCs.

Animals↗
PubMed1998

Antisense oligodeoxyribonucleotide against the MLL-LTG19 chimeric transcript inhibits cell growth and induces apoptosis in cells of an infantile leukemia cell line carrying the t(11;19) chromosomal translocation.

To clarify the role of the multiple lineage leukemia gene-leukemia translocation gene of chromosome 19 (MLL-LTG19) protein in leukemogenesis, we synthesized antisense oligodeoxyribonucleotide (ODN) against the fused region of the MLL-LTG19 chimeric transcript and treated KOCL33 cells carrying the t(11;19) translocation with antisense ODN. The antisense ODN inhibited cell growth and induced apoptosis in KOCL33 cells but not in Daudi cells, which have no t(11;19). The levels of MLL-LTG19 mRNA and MLL-LTG19 protein in KOCL33 cells treated with antisense ODN were shown to decrease with time by reverse transcription-PCR and Western blot analysis. These results suggest that the MLL-LTG19 fusion protein contributes to cell proliferation and malignant transformation in infantile acute leukemia cells carrying the t(11;19) translocation.

Apoptosis↗
PubMed1998

A single missense mutant of Smad3 inhibits activation of both Smad2 and Smad3, and has a dominant negative effect on TGF-beta signals.

A missense mutation of Smad2 identified in cancer cells was reconstructed on the corresponding residue of Smad3. This mutant, Smad3D407E, was not phosphorylated by the constitutively active form of type I receptor for transforming growth factor-beta (TGF-beta), and inhibited the phosphorylation of co-expressed wild-type Smad2 and Smad3. This mutant also had a dominant negative effect on the growth inhibition of HaCaT cells and on the expression of p3TP-lux reporter gene induced by TGF-beta. However, it did not alter the phosphorylation of Smad1 induced by the constitutively active form of the bone morphogenetic protein type IA receptor. These findings showed that a single missense mutation in Smad3 could specifically block TGF-beta signals by preventing activation of both Smad2 and Smad3.

Amino Acid Sequence↗
PubMed1998

Low-density lipoprotein receptor genotype-dependent response to cholesterol lowering by combined pravastatin and cholestyramine in familial hypercholesterolemia.

We compared the effects of cholesterol-lowering therapy on 2 patient groups genetically defined as heterozygous for familial hypercholesterolemia (FH), 5 with a deletion of exon 15 (FH(Tonami-1)), and 7 with a point mutation at codon 664 (FH(Kanazawa-2)). There were significant differences in both serum and low-density lipoprotein cholesterol reductions between the 2 groups after combination therapy with pravastatin and cholestyramine, and the overall effect of genotype on serial changes in both was significant.

Adult↗
PubMed1998

Growth inhibition by overexpression of human DEAD box protein rck/p54 in cells of a guinea pig cell line.

We transfected cells of a guinea pig cell line with RCK cDNA inserted in a pIRES1neo expression vector. The overexpression of rck/p54 was confirmed by Western blot and RT-PCR analysis. In two clones expressing rck/p54, the cell growth was highly inhibited; and their anchorage-independent growth, which is an important character of malignant transformation, was not found. These findings are the first evidence that the overexpression of a DEAD box protein/RNA helicase could inhibit substantially cell growth at the translational level.

Animals↗