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Biomedical subjects

K Itoh

Publications and source records attributed to K Itoh.

At least 595 records · Page 33Linked to original sources
PubMed1997

Transposon tagging in rice.

To develop an efficient gene isolation method for rice we introduced the maize Ac/Ds system into rice. Extensive analysis of their behavior in rice for several generations indicated that Ac and Ds in the presence of Ac transposase gene actively transpose in rice. A wide spectrum of mutations affecting growth, morphogenesis, flowering time and disease resistance have been obtained in the population carrying Ac/Ds and some of them were genetically analyzed. Main efforts are currently being made to isolate genes responsible these mutations. In addition, a number of Ac/Ds were mapped on chromosomes and mapped elements will be used in the future for directed tagging of genes with known chromosomal positions.

Cloning, Molecular↗
PubMed1997

[Clinical effect of alprazolam and trazodone on bronchial asthmatics with anxiety disorder].

Onset as well as many symptoms of asthma are said to be related to autonomic dysfunction which often appear as a result of actual daily stress of the patients. Minor tranquilizers and anti-depressants are often successful in treating such symptoms, though precise effect of these drugs on asthma is not yet available, while many still hesitate to use these drug for fear of the anticholinergic effect which may hinder the efficient expectoration of sputum which could be critical during severe asthma attacks. In this study, these drugs were evaluated by the asthma score, peak flow, acetylcholine provocation test and the suppressive effect on lymphocytes. They could be beneficial in increasing the quality of asthma therapy if employed with necessary care.

Adult↗
PubMed1997

Physical characteristics of a new synthetic fiber mattress in relation to pressure sores.

The purpose of the present investigation was to develop a mattress which was made of the new synthetic fibers called 'Shin-Gosen', and to determine its physical characteristics associated with pressure sores such as pressure distribution, temperature and humidity. The Shin-Gosen mattress consisted of three layers of elastic fibers made of polyester multifilaments, which were mediated by four layers of wave-like fabrics made of nylon monofilaments. The physical characteristics of the mattress were compared with (a) the conventional cotton hospital mattress and (b) the SORELESS MAT made of vacuole gel which effectively eliminated compression forces. The Shin-Gosen mattress was found to provide pressure relief effects similar to that of the SORELESS MAT the desired thermal insulation as well as that of the cotton mattress and a higher level of moisture vapor permeability. These excellent features will not only contribute to preventing pressure sores, but will also enable comfortable resting and sleeping.

Aged↗
PubMed1997

[A case of fluorouracil-induced pneumonitis].

A 73-year-old man with colon cancer had been treated elsewhere for pneumonia on June 12, 1994. He was admitted to our hospital on June 21 with progressive dyspnea and bilateral diffuse infiltrates on chest X-ray. On admission, plain chest radiographs and chest CT scans revealed bilateral interstitial shadows predominantly in the outer zone, of the lower lobes. After an operation for rectal cancer, he had begun taking orally 300 mg of fluorouracil daily for 64 days. A drug lymphocyte stimulation test (DLST) was positive for fluorouracil. Fluorouracil-induced pneumonitis was subsequently diagnosed. To the best of our knowledge, there have been no previous case reports of fluorouracil-induced pneumonitis, and it seems likely that this pneumonitis resulted from both toxic and allergic reactions to the drug.

Administration, Oral↗
PubMed1997

[Can 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) evaluate the renal function without blood sampling?: consensus report from multicenter study].

A multicenter study was undertaken in Japan to evaluate the correlation between the percentage of renal uptake of 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) estimated by the count-based gamma camera method and the blood clearance of 99mTc-MAG3. Twenty four centers were enrolled and 172 cases were finally analyzed in this study. The renal clearance of 99mTc-MAG3 (TER) was obtained by using a single blood sample taken at 44 min after injection. Comparison of TER and renal uptake provided a coefficient of correlation of 0.874; suggesting that sufficiently accurate quantification of renal function could be obtained from the renal uptake estimate by the gamma camera method. This study also showed that the comparison of renal function might be feasible among patients under the same protocols, although precise and careful consideration is required in each center.

Adolescent↗
PubMed1996

Mutant of insulin receptor substrate-1 incapable of activating phosphatidylinositol 3-kinase did not mediate insulin-stimulated maturation of Xenopus laevis oocytes.

Insulin receptor substrate-1 (IRS-1) is rapidly phosphorylated on multiple tyrosine residues in response to insulin and binds several Src homology 2 domain-containing proteins, thereby initiating downstream signaling. To assess the tyrosine phosphorylation sites that mediate relevant downstream signaling and biological effects, we created site-directed mutants of IRS-1 and overexpressed them in the Xenopus laevis oocyte. In oocytes overexpressing IRS-1 or IRS-1-895F (Tyr-895 replaced with phenylalanine), insulin activated phosphatidylinositol (PI) 3-kinase, p70 S6 kinase, and mitogen-activated protein kinase and induced oocyte maturation. In contrast, in oocytes overexpressing IRS-1-4F (Tyr-460, Tyr-608, Tyr-939, and Tyr-987 of IRS-1 replaced with phenylalanine), insulin did not activate PI 3-kinase, p70 S6 kinase, and mitogen-activated protein kinase and failed to induce oocyte maturation. These observations indicate that in X. laevis oocytes overexpressing IRS-1, the association of PI 3-kinase rather than Grb2 (growth factor-bound protein 2) with IRS-1 plays a major role in insulin-induced oocyte maturation. Activation of PI 3-kinase may lie upstream of mitogen-activated protein kinase activation and p70 S6 kinase activation in response to insulin.

Adaptor Proteins, Signal Transducing↗
PubMed1996

Only sphingolipid activator protein B (SAP-B or saposin B) stimulates the degradation of globotriaosylceramide by recombinant human lysosomal alpha-galactosidase in a detergent-free liposomal system.

The degradation of globotriaosylceramide (GbO-se3Cer) by insect-cell derived recombinant human alpha-galactosidase (EC 3.2.1.22) was carried out in a detergent-free liposomal system in order to mimic intralysosomal conditions. GbOse3Cer incorporated into unilamellar liposomes was used as the substrate, and naturally occurring sphingolipid activator proteins, rather than detergents, were used to stimulate the enzyme reaction. The degradation of GbOse3Cer was dependent on the presence of both alpha-galactosidase and sphingolipid activator protein B (SAP-B or saposin B). It proceeded optimally at pH 4.6, and was enhanced by increasing amounts of both alpha-galactosidase (0.24-24 mU/50 microliters assay) and SAP-B (0-5 micrograms/50 microliters assay). The enzyme reaction was not affected by SAP-A, SAP-C, or SAP-D. Therefore, our results indicate that only SAP-B is essential for the degradation of GbOse3Cer by alpha-galactosidase.

Animals↗
PubMed1996

The burst firing in the layer III and V pyramidal neurons of the cat sensorimotor cortex in vitro.

We identified the burst and single-spiking cells, and the repetitive bursting cells in layers III and V of the cat sensorimotor cortex with intracellular recording and staining techniques. Both types of the bursting cells were found in 22.7% of the recorded layer V neurons and in 23.1% of the recorded neurons in layer III. The bursting cells were characterized by the prominent afterdepolarization (ADP) which was usually reaching the threshold depolarization. Intracellular staining revealed that the morphology of the bursting cells was not so different from that of the regular-spiking cells in the cat.

Adenosine Diphosphate↗
PubMed1996

Determinants of polyreactivity in a large panel of recombinant human antibodies from HIV-1 infection.

A considerable part of the Ab repertoire is given over to polyreactive Abs capable of interacting with multiple antigenic species. Neither the function of these Abs nor the molecular basis for their activity is known. To address the latter problem, we have compared the amino acid sequences of a large panel (n = 70) of polyreactive human monoclonal Fab fragments and conducted a series of engineering experiments on a prototype polyreactive Fab. The Fab fragments were retrieved from combinatorial IgG libraries prepared from the bone marrow of long term asymptomatic HIV-1 seropositive donors. The general features displayed by the panel of IgG polyreactive Abs include 1) skewed VH family usage with a predominance of VH1 and VH4 clones and a paucity of the normally prevalent VH3 family; 2) use of a variety of different VH germ-line genes within the context of the family usage and no restriction in D or JH gene usage; 3) skewed VL gene usage: 75% of Fabs used one of two germ lines; and 4) extensive somatic modification of both heavy and light chains. The importance of the heavy chain, in particular the heavy chain CDR3 (HCDR3), in dictating the polyreactive phenotype was demonstrated for the prototype Fab by chain shuffling and CDR transplantation experiments. in addition, and most strikingly, a constrained peptide based on the HCDR3 sequence was shown to be polyreactive and to inhibit binding of the parent Ab to a panel of Ags. A role for conformational flexibility in polyreactivity was suggested by a marked temperature dependence of Ab recognition of Ag. One Ab was shown to be polyreactive at 37 degrees C, but was apparently monoreactive at 4 degrees C. We hypothesize that Ab polyreactivity is associated with conformationally flexible HCDR3 regions in the context of certain favorable framework configurations.

Amino Acid Sequence↗
PubMed1996

Effect of intranasal administration of thyrotropin-releasing hormone on ataxic gait in staggerer mice.

The ataxia ameliorating effect of an intranasal administration of thyrotropin-releasing hormone (TRH) was examined using normal and ataxic staggerer mutant mice. In the normal mice, the blood TRH level reached the maximum level 5 min after administration and was gradually eliminated during the following 60 min. The antiataxic effects of TRH in the staggerer mice was examined using an open field method. At lower doses, the intranasal administration of TRH in the staggerer mice was examined using an open field method. At lower doses, the intranasal administration of TRH did not exert any evident effect. However, at 3 mg or 4 mg, the fall index (the ratio of the number of falls to the movement score) was significantly decreased for 20 min after the administration. These results show that an intranasal administration of TRH can ameliorate the ataxia in staggerer mice, and may be promising for clinical use in patients with spinocerebellar degeneration.

Animals↗
PubMed1996

Flow Cytometric Assay of c-erbB-2 Protein in Fine Needle Aspirates of Fresh and Frozen Human Breast Cancer Tissues.

Using FCM (flow cytometry), we analyzed the ErbB-2 (c-erbB-2 protein) status of 61 breast cancer tissue samples obtained by FNAB (fine-needle aspiration biopsy). The number of cancer cells collected by FNAB from fresh samples was 1.7+/-0.7 x10&sup5;, 2.5 +/-0.6 x10&sup5;, and 4.0+/- 0.8x10 &sup5;, by single, double and triple aspirations, respectively. A mean of 3.0+/-0.6 x10&sup5;cells was collected on three aspirations from frozen samples. The number of cells collected on three aspirations was sufficient for the measurement of ErbB-2. Cells with higher ErbB-2 levels than those of normal human lymphocytes were designated ErbB-2 positive cells. The mean overall for ErbB-2 positive cell rates was 20.5 +/- 27.9 % (mean+/-SD). The rates were 27.9 +/- 31.6 % in patients with recurrence and 15.9 +/- 24.4% in patients without recurrence. When the cut-off value was set at 20% of the positive cell rate (P =0.008, generalized Wilcoxon test), patients with ErbB-2 negative tumors showed highly significantly longer survival without recurrence (P=0.008, generalized Wilcoxontest) and better overall survival rates (P=0.013) than patients with ErbB-2 positive tumors. Among 61 specimens, 16 (26.2%) scored positive for ErbB-2 by FCM. These finding indicated that the analysis of ErbB-2 status using FCM of samples obtained by FNAB should be useful for preoperatively evaluating the prognosis of patients with breast cancer.

Journal Article↗
PubMed1996

Pathway for Ca2+ influx into cells by trichosporin-B-VIa, an alpha-aminoisobutyric acid-containing peptide, from the fungus Trichoderma polysporum.

Trichosporin (TS) -B-VIa, a fungal alpha-aminoisobutyric acid (Aib) -containing peptide consisting of 19 amino acid residues and a phenylalaninol, produced both 45Ca2+ influx into bovine adrenal chromaffin cells and catecholamine secretion from the cells. The secretion induced by TS-B-VIa at lower concentrations (2-5 microM) was completely dependent on the external Ca2+, while that induced by TS-B-VIa at higher concentrations (10-30 microM) was partly independent of the Ca2+. The concentration-response curves (2-5 microM) for the TS-B-VIa-induced Ca2+ influx and secretion correlated well. The TS-B-VIa (at 5 microM) -induced secretion was not antagonized by diltiazem, a blocker of L-type voltage-sensitive Ca2+ channels. The treatment of fura-2-loaded C6 glioma cells with TS-B-VIa (2-5 microM) led to an increase in the intracellular free Ca2+ concentration ([Ca2+]i) in a concentration-dependent manner but the stimulatory effects of TS-B-VIa on [Ca2+]i were only slightly observed in Ca(2+)-free medium, indicating that TS-B-VIa causes Ca2+ influx from the external medium into the C6 cells. The TS-B-VIa-induced increase in [Ca2+]i in the C6 cells was not antagonized by diltiazem and by SK&F 96365, a novel blocker of receptor-mediated Ca2+ entry. High K+ increased neither [Ca2+]1 in the C6 cells nor Mn2+ influx into the cells, while TS-B-VIa increased Mn2+ influx. Also in other non-excitable cells, bovine platelets, similar results were obtained. These results strongly suggest that the mechanism of Ca2+ influx by TS-B-VIa at the lower concentrations is distinct from the event of Ca2+ influx through receptor-operated or L-type voltage-sensitive Ca2+ channels in both excitable cells (the chrornaffin cells) and non-excitable cells (the C6 cells and the platelets) and that TS-B-VIa per se may form Ca(2+)-permeable ion channels in biological membranes. On the other hand, the peptide at the higher concentrations seems to damage cell membranes.

Adrenal Glands↗