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Biomedical subjects

N Shibuya

Publications and source records attributed to N Shibuya.

At least 19 recordsLinked to original sources
PubMed2006

Apocrine adenocarcinoma of possible sweat gland origin in a male rabbit.

A five-year-old, male crossbreed rabbit was referred for acute caudal abdominal swelling. On physical examination, the rabbit was slightly depressed and showed an enlarged subcutaneous cyst in the caudal abdomen and an adjacent small, ulcerated solid mass. A drainage tube was placed in the cystic area, and surgical resection of the solid mass was performed. The histopathological diagnosis of the mass was apocrine adenocarcinoma. To the authors' knowledge, this report describes the first case of spontaneous apocrine adenocarcinoma of possible sweat gland origin in a male rabbit.

Adenocarcinoma↗
PubMed2001

t(10;11)-acute leukemias with MLL-AF10 and MLL-ABI1 chimeric transcripts: specific expression patterns of ABI1 gene in leukemia and solid tumor cell lines.

The recurrent translocation t(10;11) is associated with acute myeloid leukemia (AML). The AF10 gene on chromosome 10 at band p12 and MLL at 11q23 fuse in the t(10;11)(p12;q23). Recently, we have identified ABI1 as a new partner gene for MLL in an AML patient with a t(10;11)(p11.2;q23). The ABI1 is a human homologue of the mouse Abl-interactor 1 (Abi1), encoding an Abl-binding protein. The ABI1 protein exhibits sequence similarity to homeotic genes, and contains several polyproline stretches and a src homology 3 (SH3) domain. To clarify the clinical features of t(10;11)-leukemias, we investigated 6 samples from acute leukemia patients with t(10;11) and MLL rearrangement and detected MLL-AF10 chimeric transcripts in 5 samples and MLL-ABI1 in one. The patient with MLL-ABI1 chimeric transcript is the second case described, thus confirming that the fusion of the MLL and ABI1 genes is a recurring abnormality. Both of the patients with MLL-ABI1 chimeric transcript are surviving, suggesting that these patients have a better prognosis than the patients with MLL-AF10. To investigate the roles of AF10 and ABI1 further, we examined the expression of these genes in various cell lines and fresh tumor samples using the reverse transcriptase-polymerase chain reaction method. Although AF10 was expressed in almost all cell lines similarly, the expression patterns of ABI1 were different between leukemia and solid tumor cell lines, suggesting the distinctive role of each isoform of ABI1 in these cell lines. We also determined the complete mouse Abi1 sequence and found that the sequence matched with human ABI1 better than the originally reported Abi1 sequence. Further functional analysis of the MLL-AF10 and MLL-ABI1 fusion proteins will provide new insights into the leukemogenesis of t(10;11)-AML.

Acute Disease↗
PubMed2001

Effects of ketamine on voltage-dependent calcium currents and membrane potentials in single bullfrog atrial cells.

PURPOSE: This study was undertaken to assess the effect of ketamine on L-type calcium channel current (I(Ca)) and membrane action potential in the bullfrog single atrial myocyte. METHODS: Bullfrog single atrial myocytes were prepared by enzymatic dispersion. Whole-cell voltage-clamp technique and current clamp technique were used to monitor I(Ca), membrane resting potential, and action potential. RESULTS: Ketamine (10(-5)-10(-3) M) showed dose-dependent inhibition of I(Ca) in a reversible manner. The 50% inhibitory concentration (IC(50)) of ketamine on I(Ca) was estimated to be 0.92 x 10(-5) M. Use-dependent block of I(Ca) was not observed. The resting membrane potential was depolarized at a high concentration (10(-4) M) of ketamine. Reduction of the plateau phase and prolonged duration of the action potential were observed in the presence of a high concentration of ketamine (10(-4) M). CONCLUSION: Ketamine has an inhibitory effect on I(Ca) in the bullfrog single atrial myocyte, and a high dose (10(-4) M) of ketamine prolonges the duration of the action potential. The mechanism of inhibition of I(Ca) seems to be a direct effect on the L-type calcium channel, not like an open channel blocker.

Journal Article↗
PubMed2001

Isolation and analysis of expression mechanisms of a rice gene, EL5, which shows structural similarity to ATL family from Arabidopsis, in response to N-acetylchitooligosaccharide elicitor.

Two rice cDNAs, EL5 and RRF1, were isolated and characterized. EL5 was responsive to N-acetylchitooligosaccharide, a biotic elicitor active in suspension-cultured rice cells. The structural specificity of the elicitor required for the expression of EL5 was consistent with other defense reactions observed in the experimental system, indicating that the elicitor signal to EL5 is transmitted through a single class of receptor-mediated recognition events. However, the intracellular signaling pathway to EL5 was distinct from those to other elicitor-responsive genes. Sequence analysis and alignment showed that a genomic sequence stored in rice genome databases in addition to EL5 and RRF1 belongs to the ATL family of RING-H2 finger motif proteins first isolated from Arabidopsis.

Journal Article↗
PubMed2001

Plasmapheresis affects T helper type-1/T helper type-2 balance of circulating peripheral lymphocytes.

Plasmapheresis not only removes humoral factors, but may also modulate cellular immunity. We investigated whether plasmapheresis influenced T helper type-1/T helper type-2 (Th1/Th2) cytokine-producing-cell balance in 3 patients with neuroimmunological disease. The production of interferon-gamma (IFN-gamma), interleukin-2 (IL-2), and IL-4 in the culture supernatant of peripheral blood mononuclear cells stimulated by anti-CD3 and anti-CD28 was assayed. In 2 of 3 patients, plasmapheresis (immunoadsorption or plasma exchange) reduced Th1/Th2 cytokine ratio. The results may suggest that plasmapheresis induces a shift of Th1/Th2 balance in peripheral blood.

Humans↗
PubMed2001

Binding site for chitin oligosaccharides in the soybean plasma membrane.

Affinity cross-linking of the plasma membrane fraction to an (125)I-labeled chitin oligosaccharide led to the identification and characterization of an 85-kD, chitin binding protein in plasma membrane-enriched fractions from both suspension-cultured soybean cells and root tissue. Inhibition analysis indicated a binding preference for larger (i.e. degrees of polymerization = 8) N-acetylated chitin molecules with a 50% inhibition of initial activity value of approximately 50 nM. N-Acetyl-glucosamine and chitobiose showed no inhibitory effects at concentrations as high as 250 microM. It is noteworthy that the major lipo-chitin oligosaccharide Nod signal produced by Bradyrhizobium japonicum was also shown to be a competitive inhibitor of ligand binding. However, the binding site appeared to recognize the chitin portion of the Nod signal, and it is unlikely that this binding activity represents a specific Nod signal receptor. Chitooligosaccharide specificity for induction of medium alkalinization and the generation of reactive oxygen in suspension-cultured cells paralleled the binding activity. Taken together, the presence of the chitin binding protein in the plasma membrane fraction and the specificity and induction of a biological response upon ligand binding suggest a role for the protein as an initial response mechanism for chitin perception in soybean (Glycine max).

Binding Sites↗
PubMed2001

[Memory function in patients with Parkinson's disease: in relation to neuropsychological tests and cerebral blood flow].

We conducted a neuropsychological comparison between Parkinson's disease (PD; n = 24) and healthy control subjects (n = 12) using Rey's auditory-verbal learning test (RAVLT) and the Rey-Osterrieth complex figure test (RCFT) assessing memory function. In addition, to determine the function of cortical and subcortical areas, we measured the regional cerebral blood flow (rCBF) using N-isopropyl-p[123I]-iodoamhetamine (123I-IMP) and single photon emission computed tomography (SPECT) and analyzed the relationships between brain regions and memory function. On the RAVLT, significant group differences in recall words were found on all learning trials between patients with PD and control subjects, whereas recognition, learning rate and forgetting rate were basically the same. In addition, the primacy/recency effect was statistically equal for both groups. Results suggest faulty retrieval mechanisms in PD, whereas encoding and retention procesess did not prove to be affected. There were significant correlations between perfusion of the prefrontal and parietal cortices and total number of free recall in five trials. On the RCFT, recalls after 30 sec and 30 min were impaired in patients with PD although no significant difference in accuracy scores obtained in copy was noted. A percent recall score calculated using the formula 100 x [1 - (copy-recall)/copy] was also decreased in patients with PD. There were significant correlations between perfusion of the occipital and parietal cortices and percent recall score. Our data suggest that auditory memory deficits based on the RAVLT in PD may be mainly related to frontal and parietal cortical dysfunction, while visual recall deficits based on the RCFT may be related to the parieto-occipital cortical dysfunction.

Aged↗
PubMed2000

Elicitor action via cell membrane of a cultured rice cell demonstrated by the single-cell transient assay.

In order to analyze intracellular signal transduction, we investigated the mechanism of chemical elicitor action by single-cell transient assay using green fluorescent protein (GFP) as a reporter gene. When the elicitor was applied from outside the cell into which the chitinase promoter and GFP reporter were introduced beforehand, fluorescence emission of GFP was observed. In contrast, when the elicitor was introduced in the cell to let the elicitor act from inside, no emission was observed. Addition of further elicitor from outside, however, did cause GFP emission. Therefore, it is clear that the elicitor does not act after entering the cell but that its signal is transduced into the cell via the cell membrane.

Cells, Cultured↗
PubMed2000

Saccharide production from methanol by transposon 5 mutants derived from the extracellular polysaccharide-producing bacterium Methylobacillus sp. strain 12S.

A CH3OH-utilizing bacterium that has the ability to produce extracellular polysaccharide (EPS) was isolated from a soil sample, and was identified as the obligate methylotroph Methylobacillus sp. strain 12S on the basis of its 16S rDNA sequence and growth-substrate specificity. The EPS produced by strain 12S was purified and the sugar composition was analysed by GC-MS and HPLC to reveal that the EPS was a heteropolymer composed of glucosyl, galactosyl, and mannosyl residues in the molar ratio 3:1:1. In order to produce mono- and/or oligosaccharides by single-step fermentation from CH3OH, stain 12S was mutagenized by transposon 5. Among eleven EPS-deficient mutants, three strains were found to accumulate significant amounts of reducing sugars in the media. The amounts of the reducing sugars produced by the mutants ( > ca. 700 mg glucose equivalent/l) were > 11-22 times higher than those produced by the wild-type strain (<ca. 60 mg glucose equivalent/l). The GC-MS analysis showed that all the mutants accumulated glucose, erythrose, threose and a disaccharide-like compound in the media.

Chromatography, High Pressure Liquid↗
PubMed2000

Differences in the recognition of glucan elicitor signals between rice and soybean: beta-glucan fragments from the rice blast disease fungus Pyricularia oryzae that elicit phytoalexin biosynthesis in suspension-cultured rice cells.

Partial acid/enzymatic hydrolysis of the beta-(1-->3, 1-->6)-glucan from the cell walls of the rice blast disease fungus Pyricularia oryzae (Magnaporthe grisea) released elicitor-active fragments that induced phytoalexin biosynthesis in suspension-cultured rice cells. From the digestion of the glucan by an endo-beta-(1-->3)-glucanase, one highly elicitor-active glucopentaose was purified as a reduced compound, tetraglucosyl glucitol. The structure of this tetraglucosyl glucitol as well as two other related tetraglucosyl glucitols was elucidated as follows: (1) Glcbeta(1-->3)Glcbeta(1-->3)(Glcbeta(1-->6)) Glcbeta(1-->3)Glucitol (most active fragment); (2) Glcbeta(1-->3)(Glcbeta(1-->6))Glcbeta(1-->3)Glcbeta (1-->3)Glucitol; and (3) Glcbeta(1-->6) Glcbeta(1-->3)Glcbeta(1-->3)Glcbeta(1-->3)Glucitol. However, a synthetic hexa-beta-glucoside, known as a minimal structural element for the phytoalexin elicitor for soybean cotyledon cells, did not induce phytoalexin biosynthesis in the rice cells. Conversely, the beta-glucan fragment from P. oryzae did not induce phytoalexin biosynthesis in the soybean cotyledon cells, indicating differences in the recognition of glucooligosaccharide elicitor signals in these two plants. Because rice cells have been shown to recognize chitin fragments larger than pentamers as potent elicitors, these results also indicate that the rice cells can recognize at least two types of oligosaccharides from fungal cell walls as signal molecules to initiate defense response.

Carbohydrate Sequence↗
PubMed2000

Short-term effects of prednisolone on neuromuscular transmission in the isolated mdx mouse diaphragm.

To determine the mechanism of the beneficial effects of prednisolone on Duchenne muscular dystrophy (DMD), we examined the short-term effects of prednisolone on neuromuscular transmission by using conventional microelectrode methods in the mdx mice. High (56 micromol/liter) and low (2.8 micromol/liter) concentrations of prednisolone were applied to a bath containing phrenic nerve-diaphragm preparations from mdx mice, and several parameters related to neuromuscular transmission were recorded. The high dose of prednisolone significantly decreased parameter n on quantal release by nerve impulse and decay time-constant of end-plate potentials, which showed adverse effect on neuromuscular transmission. The low dose of prednisolone did not significantly increase quantal content, but could assist the compensatory reaction to maintain the safety margin of neuromuscular transmission in the mdx mice. Our results suggest that the latter effect represents one of the possible mechanisms of the therapeutic effects of prednisolone on DMD.

Animals↗
PubMed2000

[A case of common variable immunodeficiency with intractable diarrhea and the functional disorder of renal tubules].

We report a case of a 31-year-old woman with common variable immunodeficiency (CVID) complicated with intractable diarrhea and the functional disorder of renal tubules. The patient became hypogammaglobulinemic after she suffered from measles at 6 years of age. She also suffered from lupus-like syndrome at 7 years of age. The complete remission was obtained by glucocorticosteroid treatment. An intravenous immunoglobulin replacement therapy was introduced at 11 years of age, since then her general condition was stable for more than 20 years. When she was 29 years old, she suffered from generalized malaise, anorexia with body weight loss, and numbness of face. The intractable diarrhea as protein loosing syndrome, and the severe abnormality of electrolyte balance with metabolic acidosis as the functional disorder of renal tubules were found. Her condition was not improved by the electrolytes or alkali replacement therapy. She was admitted for further evaluation and treatment. The intractable diarrhea and the functional disorder of renal tubules were dramatically improved after absolute restriction of food intake under hyperalimentation. When she began to take food, the symptom and sign became worse again. The interstitial nephritis and nonspecific inflammation of intestine were found by the tissue biopsy. The most characteristic finding was the infiltration of lymphocytes (predominantly CD 8 + T lymphocytes) in both intestinal mucosa and renal interstitium. The introduction of glucocorticosteroids improved her general condition and biochemical findings. This CVID case is complicated with intractable diarrhea and the functional disorder of renal tubules which is associated with the infiltration of CD 8 + lymphocytes in intestine and kidney. We consider that such case is very rare and valuable to report.

Adult↗
PubMed2000

[Neuropsychological comparison between corticobasal degeneration and progressive supranuclear palsy].

We conducted a neuropsychological comparison among cases with corticobasal degeneration (CBD; n = 8), those with progressive supranuclear palsy (PSP; n = 5) and healthy control subjects (n = 12) using an extensive neuropsychological battery assessing memory and executive functions. There were no significant differences among three groups for age, education, scores on the Mini-Mental State Examination and Zung's self-rating depression scale. Both patient groups showed retrieval impairment without recognition difficulties, and a dysexecutive syndrome. Along with those similarities, we observed some differences between CBD and PSP patients. Memory impairments in CBD patients were more marked than PSP patients in Rey's complex figure test, while they were less prominent in Rey's auditory verbal learning test. Perseverative errors of Nelson in Wisconsin card sorting test (Keio version) were more marked in CBD patients than in PSP patients. These two diseases showed memory and executive dysfunctions probably due to subcortico-frontal dysfunction. Some neuropsychological differences may help to distinguish CBD clinically from PSP.

Aged↗
PubMed2000

[Clinical courses of 18 cases with food-dependent exercise-induced anaphylaxis].

Eighteen cases (7 males and 11 females) of food-dependent exercise-induced anaphylaxis were observed for several years. The age of the patients at the first visit to our hospital ranged from 9 to 43 years (average 24.3 years). The offending foods were wheat in 9 cases, shrimp in 2 cases, shellfish in 1 case, fish in 1 case, and unknown foods in 5 cases. The inducing exercises were ball play games, running, riding a bicycle, swimming, kendo (Japanese fencing), walking, and so on. We advised these patients to avoid eating offending foods or taking exercises, or to take antiallergic medicine such as DSCG, and repirinast. We observed their clinical courses and laboratory data for 2 to 10 years. Only a few cases relapsed anaphylactoid reactions, but all cases have improved until now. In some cases, IgE RAST scores for wheat decreased. In other cases, the rate of histamine release on anti-IgE stimulation decreased after taking DSCG.

Adolescent↗