K Tanaka
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Pubmed
Journal: Biochemical and biophysical research communications
September/24/1996
Abstract
The Rho family small G proteins are implicated in various cell functions, such as cell morphological change, cell motility, and cytokinesis. However, their modes of action in regulating these cell functions remain to be clarified. In the present study, we have isolated a cDNA encoding a protein which interacts with the GTP-bound form, but not with the GDP-bound form, of the Rho family members, including RhoA, Racl, and Cdc42, by the yeast two-hybrid method. This protein is kinectin, known to be a vesicle membrane anchoring protein of kinesin, which is an ATPase motor transporting vesicles along microtubules.
Pubmed
Journal: Experimental brain research
June/5/1989
Abstract
Based on the fact that a great majority of cells in the middle temporal (MT) area of the macaque respond to movement of luminance contours with directional selectivity, this area has been thought to be concerned with the analysis of visual motion. However, objects can be discriminated from the background not only by differences in luminance but also by differences in color. It is possible that color signals are also used for motion analysis in MT. In the present study, we examined whether MT cells respond to movement of a pattern composed of pure color-contours. Using a color TV system, a moving color bar was displayed on a uniform background whose color was opponent with that of the bar. The main bar/background color combination we examined was magenta/cyan. Yellow/blue and cyan/magenta combinations were also examined for some cells. The response of MT cells to movements of opponent-color stimuli was recorded while the bar/background luminance ratio was changed from 1/10 to 10/1. In half of 89 cells tested in 3 monkeys, the response decreased considerably (disappeared completely in some cells) at a luminance ratio close to the human equiluminous condition. In the other half, a directional response persisted at any bar/background luminance ratio, though the response decreased to a varied extent (30-90% of the maximum response) near the ratio 1 (human equiluminous condition). The average magnitude of the equiluminous response to the magenta/cyan stimulus for the overall population was about 35% of the maximal response when the length of the bar (0.5 degrees in width) and the movement amplitude were set to be optimal for individual cells, i.e. smaller than 15 degrees and 10 degrees of visual angle, respectively. This fall to 23% when the bar length and movement amplitude were limited to 2 degrees. The same cell responded to pure color-contours of yellow/blue as well as of cyan/magenta combinations. Thus, MT can detect the direction of movement of pure color-contours, although the sensitivity is less than for luminance contours.
Pubmed
Journal: Transplantation
March/23/1998
Abstract
BACKGROUND
In order to clarify the risk of hepatitis B virus (HBV) transmission from hepatitis B core antibody-positive (HBcAb(+)) donors and to evolve a new strategy to counter such a risk, we undertook a retrospective (1990-1995) and prospective (1995-1996) analysis of our experience with living related liver transplantation involving HBcAb(+) donors.
METHODS
Between June 15, 1990, and June 30, 1995, HBcAb(+) individuals were not excluded as donor candidates at our institutions. For 171 liver transplants, 16 donors were HBcAb(+). Between July 1, 1995, and June 30, 1996, HBcAb(+) individuals were generally excluded as donor candidates; however, three recipients were given liver grafts from HBcAb(+) donors because other donor candidates presented even higher risks. In the latter period, recipients with transplants from HBcAb(+) donors underwent prophylactic passive immunization with hyperimmune hepatitis B immunoglobulin (HBIG). The serum of 10 HBcAb(+) donors was examined by nested polymerase chain reaction for the presence of HBV-DNA, but it was not detected in any of them. However, the same examination of the liver tissue of five such donors yielded positive results in all cases.
RESULTS
In the first 5-year period, out of 16 recipients with HBcAb(+) donors, 15 became hepatitis B surface antigen-positive after transplant. The three recipients with HBcAb(+) donors during the second 1-year period, who were treated by prophylactic passive immunization with HBIG, remained hepatitis B surface antigen-negative and negative for serum HBV-DNA after transplant.
CONCLUSIONS
HBV exists in the liver of healthy HBcAb(+) individuals, but not in the blood. Therefore, HBV is thought to be transmitted to recipients by liver grafts from the HBcAb(+) donors at a significantly high rate. The prevention of viral activation and clinical disease development by means of passive immunization with HBIG seems promising, although the follow-up period in our study may be too short for any definitive conclusions.
Pubmed
Journal: The Review of scientific instruments
February/16/2009
Abstract
High k turbulence, up to 30 cm(-1), can be measured using the two dimensional CO2 laser phase contrast imaging system on LHD. Recent hardware improvements and experimental results are presented. Precise control over the lens positions in the detection system is necessary because of the short depth of focus for high k modes. Remote controllable motors to move optical elements were installed, which, combined with measurements of the response to ultrasound injection, allowed experimental verification and shot-to-shot adjustment of the object plane. Strong high k signals are observed within the first 100-200 ms after the initial electron cyclotron heating (ECH) breakdown, in agreement with gyrotron scattering. During later times in the discharge, the entire k spectrum shifts to lower values (although the total amplitude does not change significantly), and the weaker high k signals are obscured by leakage of low k components at low frequency, and detector noise, at high frequency.
Pubmed
Journal: The Journal of veterinary medical science
November/19/2000
Abstract
To determine drug-induced hyperfunction of marmoset thyroids due to inhibition of synthesis or enhancement of metabolic elimination of thyroid hormones, males were orally administered 10 and 30 mg/kg/day methimazole (MMI), 30 and 100 mg/kg/day spironolactone (SPL), or 50 mg/kg/day phenobarbital (PB) for 4 weeks. MMI caused marked hypertrophy of follicular epithelial cells in accordance with a significant decrease in the plasma thyroxin (T4) level. Hypertrophied epithelial cells were filled with dilated rough endoplasmic reticulum and reabsorbed intracellular colloids, and the luminal surface was covered with abundant microvilli. The colloid included vacuoles positive to anti T4 immuno-staining. SPL and PB also caused similar histomorphological changes, although they were less severe than those due to MMI and were not clearly associated with decrease in the plasma T4 levels. Hepatic T4 UDPGT activities tended to increase due to SPL and PB treatment, however, which were not so significant as increases in microsomal cytochrome P-450 contents. Some animals treated with SPL and PB showed marked increases in thyroid weights due to inactive dilated follicles. In conclusion, hyperactivity of thyroid follicles was induced in marmosets not only due to inhibition of T4 synthesis produced by MMI but also because of enhancement of hepatic T4 elimination produced by SPL and PB. However, hypertrophic effects of SPL and PB were less severe than MMI, because plasma T4 levels were maintained at almost pretreatment or control levels after SPL or PB treatment.
Pubmed
Journal: International journal of immunopharmacology
June/9/1999
Abstract
We previously have reported that the lactic acid bacterium, Lactobacillus casei strain Shirota (LcS), shows marked antitumor activities and an ability to modify immune responses. In this study, we examined whether LcS can induce the production of interleukin (IL)-12 and interferon-gamma (IFN-gamma), which are important cytokines for antitumor and antimicrobial immunity, from murine splenocytes in vitro in order to clarify the mechanisms of its immune modification. Stimulation by LcS induced a marked production of IL-12 by X-ray-irradiated splenocytes (X-irr-Spl). The production of IL-12 by X-irr-Spl was independent of the presence of nylon wool column-passed splenocytes (NW-Spl). IFN-gamma was produced by splenocytes by the stimulation with concanavalin A (Con A). LcS showed a synergistic stimulatory effect on the ConA-induced production of IFN-gamma. In addition, X-irr-Spl were required for the IFN-gamma; production by NW-Spl treated with LcS. The IFN-gamma production was reduced by anti-IL-12 antibody treatment. NW-Spl produced IFN-gamma following treatment with recombinant IL-12. Thus, we confirmed that IFN-gamma production by splenocytes was the result of the production of IL-12 from X-irr-Spl stimulated by LcS. Furthermore, in BALB/c mice, the oral administration of viable LcS augmented the production of IFN-gamma but not that of IL-4 or IL-5 by splenocytes. Thus, we suggested that LcS primarily activated X-irr-Spl, probably macrophages, and these cells secreted IL-12. The IL-12 induced by LcS stimulated the production of IFN-gamma.
Pubmed
Journal: The EMBO journal
August/5/1996
Abstract
We isolated mutants affected in the circadian expression of the psbAI gene in Synechococcus sp. strain PCC 7942 using a strategy that tags the genomic locus responsible for the mutant phenotype. The search identified one short period (22 h) mutant (M2) and two low amplitude mutants, one of which showed apparent arhythmia (M11) and one that was still clearly rhythmic (M16). We characterized the disrupted locus of the low amplitude but still rhythmic mutant (M16) as the rpoD2 gene, a member of a gene family that encodes sigma70-like transcription factors in Synechococcus. We also inactivated rpoD2 in a number of reporter strains and showed that the circadian expression of some genes is not modified by the loss of this sigma factor. Therefore, we conclude that rpoD2 is a component of an output pathway of the biological clock that affects the circadian expression of a subset of genes in Synechococcus. This work demonstrates a direct link between a transcription factor and the manifestation of circadian gene expression.
Pubmed
Journal: Biochemical and biophysical research communications
October/21/1996
Abstract
Presenilin 1 (PS-1) is the main causal gene of familial Alzheimer's disease. In this report, we describe the abnormal behavior of PS-1 in gel electrophoresis in the presence of SDS. Freshly in vitro synthesized PS-1 was identified as a single molecule with the molecular size of 43,000 on SDS gels but was found to disappear after incubation at 37 degrees C for 24 hr due to the formation of aggregates. Intermediate aggregates with M(r) 74,000 and 100,000 were formed before the final aggregate which was retained at the top of the gel. Thus the amount of 43,000-protein species of PS-1 was found to decrease on gels with a concomitant increase in the amount of 74,000/100,000 proteins. Similar abnormality was seen in PS-1 expressed in COS cells transfected with PS-1 cDNA. Moreover, cellular PS-1 was strongly suggested to be cleaved into the fragments with M(r) approximately 20,000 in COS and CHO cells. Fragmentation of cellular PS-1 was not affected by the missense point mutation of Ala260Val on PS-1 which was identified in a pedigree with familial Alzheimer's disease.
Pubmed
Journal: No shinkei geka. Neurological surgery
August/2/1993
Abstract
A case of fibromuscular dysplasia at the internal carotid origin is reported. A 45-year-old, right-handed woman who was in good health, experienced 5-6 second episodes of numbness and tingling in her right hand and lip. She had no history of medical illness or trauma. The patient suffered the same sort of attack almost seven years after her first episode. General examination was unremarkable. There was no sign of residual neurologic deficit. Cerebral angiography demonstrated a discrete filling defect at the internal carotid origin. There was no evidence of atherosclerosis in the intracranial or extracranial vessels. The lesion occluded approximately 58% of the lumen. A carotid endarterectomy was performed and a "web shaped" tissue was removed from the posterior aspect of the right internal carotid artery. Microscopic examination of the surgical specimen demonstrated intimal fibrosis, consistent with the diagnosis of fibromuscular dysplasia. In addition to our patients, eight other cases of cephalic fibromuscular dysplasia have been reported in the form of an internal carotid web. This type of lesion is unique because the changes involve only the intima of the vessels without involvement of the medial structure as is seen in the usual form of fibromuscular dysplasia. Moreover, 5 out of 9 patients reported had the repeated episodes of the ischemic symptom, suggesting patients with this particular lesion have higher risk for stroke than those with the usual "string of beads" lesion. In these patients, surgical treatment should be considered, especially if medical therapy is unsuccessful.
Pubmed
Journal: Transplantation proceedings
October/1/2003
Pubmed
Journal: Zeitschrift fur Lebensmittel-Untersuchung und -Forschung
July/8/1985
Abstract
A simple colorimetric method is described for the determination of ethylenediaminetetra-acetic acid (EDTA) in three kinds of foods. The samples were homogenized with 0.1 N-NaOH, then subjected to equilibrium dialysis against 0.02 N-NaOH. EDTA in the dialyzate was converted into a Cu-EDTA complex by the addition of CuSO4. Afterwards, this solution was subjected to the determination of both free and total (free plus complexed) copper ion. EDTA was calculated from the difference between the absorbances (477 nm) obtained with free and total copper ions. Analyses of mayonnaise, dressings and canned mushroom samples with EDTA added at the 1-mM level showed a recovery of greater than 98%.
Pubmed
Journal: Digestive diseases and sciences
November/9/1994
Abstract
Response to interferon (IFN) therapy for chronic hepatitis C has been determined by the alteration of serum alanine aminotransferase (ALT) values. However, eradication of hepatitis C virus (HCV) could be another aim of the therapy. Thus, we serially measured serum HCV RNA levels during therapy and for at least 12 months after cessation of therapy in 65 patients with chronic hepatitis C who received IFN-alpha (49 cases) or -beta (16 cases). The presence of HCV and its amount were measured by the combination of nested and competitive PCR. Twenty-seven patients, who were categorized as complete responders, showed sustained normalization of ALT values for more than six months posttreatment. The viral RNA titers at pretreatment were significantly lower in complete responders (logarithmic copy numbers/ml: 5.4 +/- 1.3, P < 0.001) than in partial and nonresponders. Complete response rate was significantly higher in patients with HCV genotype III (68.4%, P < 0.01) than those with type II (23.6%). Among 27 complete responders, HCV RNA became undetectable in only 13 patients six months after completion of therapy, and 11 still had low levels of viremia; however, none experienced relapse of the disease during follow-up of 12-24 months. Three complete responders showed lasting high-titered viremia, and their ALT values rose again during follow-up. Our data suggest that IFN treatment of chronic hepatitis C is often ineffective in eradicating HCV infection even in responders, and long-term follow-up study is necessary to determine the sustained beneficial effect of IFN.
Pubmed
Journal: Applied optics
October/1/2012
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Pubmed
Journal: FEBS letters
October/1/2000
Abstract
Three new nuclear genes (sigD, sigE and sigF) of Arabidopsis thaliana, encoding putative plastid RNA polymerase sigma factors, were identified and analyzed. Phylogenetic analysis revealed that higher plant sigma factors fell into at least four distinct subgroups within a diverse protein family. In addition, Arabidopsis sig genes contained conserved chromosomal intron sites, indicating that these genes arose by DNA duplication events during plant evolution. Transcript analyses revealed two alternatively spliced transcripts generated from the sigD region, one of which is predicted to encode a sigma protein lacking the carboxy-terminal regions 3 and 4. Finally, the amino-terminal sequence of the sigF gene product was shown to function as a plastid-targeting signal using green fluorescent protein fusions.
Pubmed
Journal: Acta medica Okayama
March/7/2001
Abstract
We examined the effects of FK506 and its non-immunosuppressive derivative, GPI1046, on H2O2-induced reduction of cell viability and apoptotic cell death in Neuro 2A cells. Our results suggest that the protective properties of GPI1046 against H2O2-induced reduction of cell viability are equipotent with those of FK506 and may be mediated by increased intracellular concentrations of glutathione (GSH). In addition, both FK506 and GPI1046 prevented apoptotic cell death in Neuro 2A cells, although the antiapoptotic effect of FK506 was somewhat stronger than that of GPI1046. These findings suggest that non-immunosuppressive immunophilin ligands such as GPI1046 might be potentially useful in treatment of neurodegenerative diseases without serious side effects such as immune deficiency.
Pubmed
Journal: Journal of ultrastructure research
December/26/1985
Abstract
Electron microscopic studies have been carried out on human platelets in the clot retraction. In the early stage of clot formation, platelets send out filopodia, in which thin filaments run longitudinally. The thin filaments are often observed to attach to the cell membrane where fibrin strands bind from the extracellular surface. In the later stage of clot formation, thick filaments become observable, mainly in the cell body of the platelets. These thick filaments are arranged to form an ordered array, and thin filaments run parallel to them. The thin filaments often attach to the end of the thick filaments. However, thin filaments are not seen between the arrays of thick filaments. Similar structures are also observed in the cytoskeleton of the contracted platelet. These filaments closely resemble the purified myosin aggregates formed under low ionic strength. Thus, during clot retraction, both actin and myosin in platelets are reorganized into thin and thick filaments, respectively.
Pubmed
Journal: Journal of electrocardiology
October/19/1986
Abstract
A patient with Wolff-Parkinson-White syndrome and variant angina developed progressive ST-segment elevation in the inferior leads after hyperventilation-induced right coronary artery spasm. At the same time, increasing pre-excitation ("concertina effect") developed with gradual prolongation of the AH interval on His bundle ECG. The ECG changes promptly disappeared after sublingual nitroglycerin, with termination of the chest pain. Transient ischemia induced by coronary artery spasm can be an etiology of increasing pre-excitation.
Pubmed
Journal: Journal of immunology (Baltimore, Md. : 1950)
May/27/1998
Abstract
The proteasome is a multisubunit protease responsible for the generation of peptides loaded onto MHC class I molecules. Recent evidence indicates that binding of an IFN-gamma-inducible PA28 activator complex to the 20S proteasome enhances the generation of class I binding peptides. The alpha- and beta-subunits, which constitute the PA28 activator complex in the form of an (alphabeta)3 heterohexamer, show significant amino acid sequence similarity to a protein, designated Ki or the gamma-subunit, that is capable of binding to the 20S proteasome. In this study, we describe the complete nucleotide sequences of the mouse genes, Psme1, Psme2, and Psme3, coding for the alpha-, beta-, and gamma-subunits, respectively. The overall exon-intron organizations of the three Psme genes are virtually identical, thus providing evidence that they are descended from a single ancestral gene. The promoter regions of the Psme1 and Psme2 genes contain sequence motifs that qualify as IFN-stimulated response elements, consistent with the observation that their expression is induced strongly by IFN-gamma. The Psme1 and Psme2 genes are located approximately 6 kb apart with their 3'-ends pointing toward each other on bands C2 to D1 of mouse chromosome 14, supporting the idea that they emerged by tandem duplication.
Pubmed
Journal: Endocrine journal
November/28/1994
Abstract
To investigate the efficacy of intravenous methylprednisolone pulse therapy on Graves' ophthalmopathy (GO), fifteen patients with severe GO were treated with large dose intravenous methylprednisolone (at a daily dosage of 1 g for 3 successive days). This treatment was repeated 3-5 times for 3-5 weeks. They were monitored before, 2 weeks after and 6 months after therapy by ophthalmological assessment, orbital magnetic resonance imaging (MRI), and by measuring serum antibodies to rat eye muscle (EMAB) in an enzyme linked immunosorbent assay and peripheral blood lymphocyte subsets by flow cytometry. Diplopia and periorbital edema markedly improved after treatment in 9 patients. Mean proptosis values and intraocular pressure measurements significantly decreased after pulse therapy. In 12 patients enlarged eye muscles significantly reduced in size after treatment, as determined by MRI. The overall ophthalmopathy index was improved from 4.8 +/- 2.4 to 2.5 +/- 1.6 at the end of pulse therapy (P < 0.01) and 2.4 +/- 1.5 six months after therapy (P < 0.01). Serum EMAB were detected in 8 out of 10 patients tested and their level significantly decreased after pulse therapy (from 3.3 +/- 1.4 to 2.5 +/- 1.2, P < 0.01). A significant increase in peripheral blood CD4+CD45RA+ cells was observed after pulse therapy. Increased numbers of CD11-CD8+ cells and decreased numbers of CD11+CD8++ cells were found prior to treatment and were normalized after pulse therapy. Our study indicates that methylprednisolone pulse therapy can be considered as a choice for the treatment of GO. The improvement in eye muscle involvement in these patients may be due to the effects of infused methylprednisolone on both humoral and cellular immune functions.
Pubmed
Journal: Nephron
September/2/1998
Abstract
OBJECTIVE
Pregnancy in hemodialysis (HD) patients tends to be diagnosed late because of its infrequency and the lack of validity of urine pregnancy tests, and because these patients tend to have menstrual irregularities. The outcome is influenced by pregnancy-related anemia. We investigated the characteristics of pregnancy-related anemia and whether it is a useful diagnostic clue to pregnancy in HD patients.
METHODS
We retrospectively investigated six pregnancies of 5 HD patients (mean age 30 years), including 4 patients treated with recombinant human erythropoietin (rHuEpo) and a transfusion-dependent patient with two pregnancies in the pre-rHuEpo era.
RESULTS
The mean duration of HD was 6 years, the mean duration of the patients' marriages at the time of pregnancy was 6 years, and the mean gestational age at diagnosis was 11 weeks and 4 days. The progression of anemia (an 8% decrease in the hematocrit) was detected by 8 weeks of gestation in all patients. The prepregnancy hematocrit was stable in 5 pregnancies, facilitating the detection of changes, but during one of the pregnancies of the transfusion-dependent patient the hematocrit was low and was influenced by the transfusions. The amount of rHuEpo required to attain a target hematocrit of 30% increased gradually or rapidly until delivery.
CONCLUSIONS
The progression of anemia or hyporesponsiveness to rHuEpo was a useful early diagnostic clue to pregnancy in HD patients. However, the prepregnancy hematocrit should be stabilized with rHuEpo, so that decreases can be easily detected. The precise mechanisms of hyporesponsiveness to rHuEpo, which progressed during pregnancy and subsided after delivery, remain to be clarified.
Pubmed
Journal: Journal of the neurological sciences
August/17/1998
Abstract
Effect of amino acid ergot alkaloids on glutamate transport via the human glutamate transporter (hGluT-1) was investigated using hGluT-HeLaS3 cells, which stably expressed high levels of hGluT-1. Ergotamine enhanced the glutamate uptake of hGluT-HeLaS3 cells in a concentration-dependent manner, increasing the initial velocity of glutamate uptake by 1.45 times at 10 microM. Other amino acid alkaloids, bromocriptine and dihydroergotamine, also augmented glutamate uptake, whereas amine alkaloids, ergonovine or lisuride did not influence glutamate uptake. The accelerating effect required a preincubation longer than 5 min. Kinetic studies on hGluT-1 revealed that ergot alkaloids decreased a Michaelis constant (Km) for glutamate with unchanged maximum velocity. The effect of bromocriptine was not mediated by dopamine D1 or D2 receptors, and was independent of its antioxidant action. Amino acid ergot alkaloids may serve as a prototype for agents that regulate glutamate transporters. These results may be useful in exploring new agents for neurological diseases associated with glutamatergic neurotoxicity.
Pubmed
Journal: Transplantation
December/5/1995
Pubmed
Journal: The Review of scientific instruments
February/10/2011
Abstract
Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power electron cyclotron resonance heating (ECRH) system in Large Helical Device (LHD). The necessary features for CTS, high power probing beams and receiving beams, both with well defined Gaussian profile and with the fine controllability, are endowed in the ECRH system. The 32 channel radiometer with sharp notch filter at the front end is attached to the ECRH system transmission line as a CTS receiver. The validation of the CTS signal is performed by scanning the scattering volume. A new method to separate the CTS signal from background electron cyclotron emission is developed and applied to derive the bulk and high energy ion components for several combinations of neutral beam heated plasmas.
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Pubmed
Journal: Cancer research
December/15/1982
Abstract
The dose response of tumor induction after single s.c. injections of 3-methylcholanthrene (MC) into the groin of mice and the growth rates of the tumors formed were examined. The dose-response curve of tumor induction appeared to be linear at low doses of MC. Analysis of 182 sarcomas produced between 50 and 400 days after MC injection into WB and C3H/He mice, together with previous data on ICR/JCL mice, showed that there was no correlation between the volume-doubling time of tumors and the length of time before tumor appearance or the dose of carcinogen applied. The overall average volume-doubling time of sarcomas in the three strains of mice was 2.6 days. Assuming that a tumor originates from a single cell and that its growth rate before its appearance is constant, individual growth curves were extrapolated to the time of origin of each tumor. Histograms of the distribution of times of origin of tumors showed peaks at about 50 days after application of carcinogen. A one-hit and possibly two-stage type of tumor induction with MC is proposed.
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