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T Yoshioka

Publications and source records attributed to T Yoshioka.

At least 109 records · Page 6Linked to original sources
PubMed2000

A new method for quantitative analysis of the mouse T-cell receptor V region repertoires: comparison of repertoires among strains.

We developed an adaptor ligation PCR-based microplate hybridization assay (MHA) to analyze the repertoires of mouse T-cell receptor (TCR) alpha- and beta-chain variable regions (TCRAV and TCRBV). RNA is transcribed to cDNA and an adaptor is ligated to the 5' end of the cDNA, which is then used as a template for PCR with an adaptor-specific 3' primer and a constant region-specific 5' primer. After hybridization of PCR products with TCRAV-and TCRBV-specific probes on the microplate, quantitative ELISA was carried out. The entire TCRAV or TCRBV repertoires could be analyzed using a single 96-well plate in triplicate and completed in less than 4 h. The assay results demonstrated the high level of specificity and reproducibility of this method. Furthermore, MHA results correlated well with those of fluorescence-activated cell sorting. This method may provide important information about various T-cell-associated diseases including autoimmune disease. The influence of the MHC on mouse TCR repertoires was next studied using the newly developed mouse TCRAV and TCRBV repertoire assay. The analysis in six strains showed no significant correlation between MHC haplotypes and TCRAV and TCRBV repertoires. However, large differences among strains was observed in TCRBV, but not in TCRAV repertoires. There were also large differences within same strain in TCRBV, but not in TCRAV repertoires, indicating differences in individuals independent of genetic factors. These data suggest that TCRBV repertoires are more susceptible than TCRAV repertoires not only to genetic factors but also some environmental factors.

Animals↗
PubMed2000

A method for measuring endpoint stiffness during multi-joint arm movements.

Current methods for measuring stiffness during human arm movements are either limited to one-joint motions, or lead to systematic errors. The technique presented here enables a simple, accurate and unbiased measurement of endpoint stiffness during multi-joint movements. Using a computer-controlled mechanical interface, the hand is displaced relative to a prediction of the undisturbed trajectory. Stiffness is then computed as the ratio of restoring force to displacement amplitude. Because of the accuracy of the prediction (< 1 cm error after 200 ms) and the quality of the implementation, the movement is not disrupted by the perturbation. This technique requires only 13 as many trials to identify stiffness as the method of Gomi and Kawato (1997, Biological Cybernetics 76, 163-171) and may, therefore, be used to investigate the evolution of stiffness during motor adaptation.

Arm↗
PubMed2000

Mature solid teratoma of the fallopian tube: case report.

We report a mature solid teratoma arising in the fallopian tube. The mass was noted on CT scan prior to surgery for a mature cystic teratoma of the contra-lateral ovary. Neoplasms of the fallopian tube are very uncommon. Moreover, the incidence of a mature solid teratoma of the fallopian tube is extremely low.

Adult↗
PubMed2000

Three-dimensional characterization of interior structures of exocytotic apertures of nerve cells using atomic force microscopy.

We examined the interior structure of exocytotic apertures in synaptic vesicles of neuroblastoma x glioma hybrid cells using atomic force microscopy. The atomic force microscopy detected apertures of 50-100nm in diameter at various depths within the varicosities of these cells. We were also able to image a regular radial pattern on the wall and lump-like structures at the bottom of these apertures. In contrast, scanning electron microscopy could only detect the apertures but not the fine details of their interior. The cells examined here exhibited the same electrophysiological properties and expression of synaptophysin and syntaxin 1 as presynaptic terminals, as studied by various electrophysiological and imaging techniques. Our results indicate that atomic force microscopy allows three-dimensional viewing of the fine structures located inside exocytotic apertures in nerve cells.

Calcium↗
PubMed2000

Developmental change of GABA(A) receptor-mediated current in rat hippocampus.

Developmental change of GABA(A)ergic inhibitory postsynaptic current in rat hippocampal CA3 region was examined using patch-clamp recording method. Spontaneous and evoked inhibitory postsynaptic currents were recorded from acute hippocampal slices of neonates (postnatal days 2-4) and adults (days 18-38). Decay kinetics of the spontaneous inhibitory postsynaptic current was slower in neonates than in adults. Application of 500 nM zolpidem increased decay time-constants of the inhibitory postsynaptic currents in both groups with a stronger effect on adults. Zinc (50 microM) inhibited the neonatal inhibitory postsynaptic currents but the inhibition was weaker in adults. Modification of the GABA(A)ergic inhibitory postsynaptic currents by furosemide (0.6 mM) or diazepam (100 nM) did not cause marked differences between the neonate and adult groups. These results demonstrate that GABA(A)ergic inhibitory postsynaptic currents in hippocampal CA3 pyramidal cells change developmentally and indicate that different receptor isoforms are functionally expressed between neonates and adults.

Aging↗
PubMed2000

Effects of a magnetic fields on the various functions of subcellular organelles and cells.

Magnetic fields (MF) are widely distributed in environment and their effects are increasing by the development of electrical machines. Several investigators reported that the MF might affect various functions of cells. However, an acceptable hypothesis has not yet been proposed. Thus, we studied the effects of weak MFs on various biological functions of cells, such as mitochondrial functions, stimulation dependent signal transduction of neutrophils, cell growth and transformation of HL-60 cells, H(2)O(2)-induced apoptosis and the expression of apoptotic genes in HL-60 cells. As a result of the study, a weak MF has scarcely any effects on various biological functions of cells. We also studied the direct effect of a static strong MF (SSMF, 600-2000 G) on the functions of cells or on Fe(2+)-induced lipid peroxidation and on reactive oxygen species (ROS) generation in oral polymorphonuclear leukocytes (OPMN) without stimulation using Ferrite magnets. The generation of ROS from OPMN was slightly inhibited but Fe(2+)-induced lipid peroxidation of biological membrane was slightly stimulated by exposure to the SSMF. At present, however, conclusive results have been neither obtained experimentally nor any acceptable idea proposed.

Journal Article↗
PubMed2000

Anti-metastatic efficacy and safety of MMI-166, a selective matrix metalloproteinase inhibitor.

The anti-metastatic efficacy and safety of a newly-developed matrix metalloproteinase (MMP) inhibitor were examined. MMI-166, a N-sulfonylamino acid derivative, inhibited the enzyme activity of MMP-2, 9, and 14 but not MMP-1, 3 or 7. Daily oral administration of MMI-166 resulted in potent inhibition of metastatic lung colonization of Lewis lung carcinoma injected via the tail vein and liver metastasis of C-1H human colon cancer implanted into the spleen at inhibition levels of 43% and 63%, respectively. Daily administration of MMI-166 also resulted in prolonged survival of mice given intraperitoneal implantation of Ma44 human lung cancer cells. The anti-metastatic activity of MMI-166 was as effective as that of other MMP inhibitors with broad inhibitory spectrum. MMI-166 did not affect in vitro tumor cell growth. Neither body weight losses nor hematotoxicity was observed during long-term treatment, indicating the safety of MMI-166 in mice. These results indicate that the selective MMP inhibitor MMI-166 has therapeutic potential as an anti-metastasis agent.

Animals↗
PubMed2000

Anti-NO action of carvedilol in cell-free system and in vascular endothelial cells.

1. Carvedilol, an adrenoceptor blocker with antioxidant activity, was studied for its ability to interact with NO in a cell-free condition and in an endothelial cell line (ECV304). 2. In a cell-free system, carvedilol attenuated NO-dependent reduction of carboxy-2-phenyl-4,4, 5,5-tetramethyl-imidazoline-1-oxyl-3-oxide induced by a NO donor, 1-hydroxy-2-oxo-3-(aminopropyl)-3-isopropyl-1-triazene (NOC5), which was determined by electron paramagnetic resonance (EPR) spectrometry. The EPR study also showed that nitrosylhaemoglobin formation in rat red blood cells by the addition of NO-saturated solution was attenuated by prior incubation with 0.1 - 10 microM carvedilol. 3. NO-induced fluorescence in 4,5-diaminofluorescein-2 diacethyl (DAF-2DA)-loaded ECV304 cells was attenuated by carvedilol but not by labetalol. The IC(50) of carvedilol for NOC5 or sodium nitroprusside-induced fluorescence of DAF-2DA in ECV304 cells was 1. 0x10(-7) M, which was similar to the reported IC(50) of carvedilol for the antioxidant effect. 4. Cell toxicity induced by a NO donor determined by the number of viable cells after 24 h treatment with 2-2'(hydroxynitrosohydrazino)bis-ethanamine was significantly attenuated by pretreatment with 1 microM carvedilol. 5. Both free and cell-associated carvedilol quenched NO. Because NO mediates both physiological and pathophysiological processes, NO quenching by the drug may have diverse clinical implications depending upon specific functions of local NO in tissues where carvedilol is distributed.

Animals↗
PubMed2000

Evaluation of iNOS-dependent and independent mechanisms of the microvascular permeability change induced by lipopolysaccharide.

1. Subcutaneous injection of lipopolysaccharide (LPS) increases plasma leakage in mouse skin. Pretreatment with LPS conditions mice tolerant to the LPS-induced plasma leakage. Nitric oxide (NO) has been suggested to be involved in these LPS effects. A specific role of inducible NO synthase (iNOS) was investigated in the LPS-induced plasma leakage using iNOS deficient mice. 2. Plasma leakage in mouse skin was measured by the local accumulation of Pontamine sky blue at the site of subcutaneous injection of LPS (Sal. typhimurium). LPS (100 - 400 microg site(-1)) produced a dose-related increase in dye leakage in both iNOS deficient and wild-type mice with about 40% less dye leakage in iNOS deficient mice. 3. Indomethacin (5 mg kg(-1)), N-[-2-cyclohexyloxy]-4-nitrophenyl methanesulphonamide (NS-398) (1 mg kg(-1)), diphenhydramine (10 mg kg(-1)) and anti-TNF-alpha antibody (dilution 1 : 400, 10 ml kg(-1)) inhibited the LPS-induced dye leakage in both iNOS deficient and wild-type mice, whereas N(G)-nitro-L-arginine methyl ester (L-NAME) (10 mg kg(-1)) or aminoguanidine (10 mg kg(-1)) inhibited that in wild-type but not in iNOS deficient mice. 4. Pretreatment with LPS (0.15 mg kg(-1) i.p.) 4 h before decreased the LPS-induced dye leakage in wild-type but not in iNOS deficient mice. LPS pretreatment increased serum corticosterone levels in both mice, while it increased the serum nitrate/nitrite levels in wild-type but not in iNOS deficient mice. 5. These studies indicate that an increase in vascular permeability induced by LPS is mediated by NO produced by iNOS, eicosanoids, histamine and TNF-alpha. The tolerance against LPS-induced vascular permeability change may be mediated by iNOS induction but not by an increased release of endogenous corticosteroids.

Animals↗
PubMed2000

Role of inflammatory mediators in lipid A analogue (ONO-4007)-induced vascular permeability change in mouse skin.

1. Endotoxin shock is accompanied by an increase in peripheral vascular permeability. It has been postulated that most biological activities of LPS are derived from lipid A moiety. Here we examined the effect of lipid A analogue ONO-4007 in increasing vascular permeability and the possible mediators in mouse skin by a dye leakage method. 2. Subcutaneous injection of ONO-4007 (1 - 2 mg site(-1)) induced a dose-dependent increase in vascular permeability which was evident after 120 min. 3. ONO-4007-induced dye leakage was significantly attenuated by pretreatments with anti-tumour necrosis factor-alpha (TNF-alpha) and anti-interleukin-1alpha (IL-1alpha) antibodies, but not with indomethacin (5 mg kg(-1)) or diphenhydramine (10 mg kg(-1)). ONO-4007-induced dye leakage was significantly inhibited by a pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME) (10 mg kg(-1)) but not with aminoguanidine (50 mg kg(-1)). In inducible nitric oxide synthase (iNOS)-deficient mice, ONO-4007 significantly increased the dye leakage, while ONO-4007 dilated rat thoracic aortic rings pre-contracted with phenylephrine, and the L-NAME pretreatment inhibited the dilation. 4. Thus, TNF-alpha, IL-1alpha and constitutive NOSs-derived nitric oxide but not prostaglandins or histamine play a role in ONO-4007-induced increase in vascular permeability. Although ONO-4007 mimics LPS in increasing vascular permeability, mechanisms of permeability change elicited by ONO-4007 were not identical to those of LPS.

Animals↗
PubMed2000

The impact of a catastrophic earthquake on morbidity rates for various illnesses.

It has been reported that some natural catastrophes increase morbidity rates for illness. In this study, we investigated the impact of the 1995 Hanshin-Awaji earthquake on morbidity rates for various illnesses by analysis for correlations between the extent of damage due to the earthquake and occurrences of various illnesses. We searched the medical records of 1948 patients hospitalized due to illness in 48 hospitals during the first 15 days after the earthquake. In each of 14 affected areas, the hospital admission rate and estimated morbidity ratio for each illness were calculated. Destruction ratios were determined based upon the number of dwellings completely destroyed in each area. For total illnesses and each major illness, linear regression analyses were performed comparing hospital admission rates, estimated morbidity ratios, and destruction ratios. Hospital admission rates and estimated morbidity ratios among the 1948 patients were significantly correlated to destruction ratios. With pneumonia, dehydration, acute heart failure, asthmatic attack, and peptic ulcer, hospital admission rates and estimated morbidity ratios were significantly related to destruction ratios, while no significant correlations between estimated morbidity ratios and destruction ratios existed for cerebral vascular disease or ischemic heart disease. Peptic ulcer and pneumonia showed especially high correlation values (age- and sex-adjusted R2>0.7). The present study revealed a strong link between the extent of damage due to the catastrophic earthquake and an increase in morbidity rates for acute illnesses, especially peptic ulcer and pneumonia.

Adolescent↗
PubMed2000

Restricted usage of T-cell receptor alpha-chain variable region (TCRAV) and T-cell receptor beta-chain variable region (TCRBV) repertoires after human allogeneic haematopoietic transplantation.

We analysed T-cell receptor alpha-chain variable region (TCRAV) and T-cell receptor beta-chain variable region (TCRBV) repertoires in peripheral blood mononuclear cells (PBMCs) from 34 recipients of allogeneic bone marrow transplantation (allo-BMT), seven of allogeneic peripheral blood stem cell transplantation and 19 of autologous peripheral blood stem cell transplantation using the quantitative microplate hybridization assay. TCR usage skewed at an early period (6-7 weeks) after BMT. The change was more apparent in allogeneic recipients than in autologous recipients. In particular, a predominant increase was detected in the frequency of VA1-4 (26%, 11 of 41 recipients), VA3-1 (32%) and VB24-1 (28%). Interestingly, acidic amino acid residues frequently followed the arginine residue in complementarity-determining region 3 of BV24S1. We further examined the extent of skew using samples obtained at serial time points after transplantation. The normalization of skewed repertoires occurred over a long period of time (> 8 years). There was a significant difference in the rate of normalization of skewed TCR repertoires between adult and child recipients (P < 0.05). The results suggest that these T cells may have expanded in response to allogeneic antigens, such as miHA (minor histocompatibility antigen), and that altered repertoires are eventually normalized by T-cell regeneration via a thymic-dependent pathway in children.

Adolescent↗
PubMed2000

Close linkage between calcium/calmodulin kinase II alpha/beta and NMDA-2A receptors in the lateral amygdala and significance for retrieval of auditory fear conditioning.

The general mechanism underlying memory and learning is an area under intense investigation and debate, yet this mechanism still remains elusive. Auditory fear conditioning (when a tone is paired with a foot shock) is a simple associative form of learning for which many mechanistic details are known. Lesions of the lateral/basolateral nuclei of the amygdala result in the selective impairment of fear conditioning, indicating that this is a key region for this type of learning. Fear conditioning induces a lasting synaptic potentiation in the lateral nuclei of the amygdala. In addition, recent results from several laboratories suggest that N-methyl-D-aspartate (NMDA) receptor activation in the amygdala is required for the acquisition and expression of cue-conditioned fear responses using several kinds of antagonists. Little is known, however, about the signal transduction pathway and molecular substrate underlying fear conditioning. Here we use NMDA receptor-deficient mice to demonstrate that calmodulin-dependent kinase II, CaMKIIbeta, and CaMKIIalpha activation involves the NR2A subunit in the lateral/basolateral amygdala during memory retrieval following auditory fear conditioning. These results suggest that auditory fear conditioning involves a close linkage between NMDA2A receptors and the CaMKII cascade.

Acoustic Stimulation↗
PubMed2000

A comparative study of terazosin and tamsulosin for symptomatic benign prostatic hyperplasia in Japanese patients.

OBJECTIVE: To compare the efficacy and safety of an incremental-dose regimen of terazosin (1-2 mg daily) and a fixed-dose regimen of tamsulosin (0.2 mg daily), on Japanese patients with symptomatic benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: This multicentre, single-blind, randomized trial compared terazosin and tamsulosin over 4 weeks, in 61 patients with symptomatic BPH randomly assigned to terazosin (n = 31) or tamsulosin (n = 30). Terazosin 0.5 mg twice daily was administered for 2 weeks, followed by 1 mg twice daily for 2 weeks. Tamsulosin (0.2 mg) was administered once daily for 4 weeks. Symptoms were evaluated using the International Prostate Symptom Score (IPSS), and quality of life (QOL) was assessed subjectively before treatment, and again after 2 and 4 weeks of treatment. Objective measurements taken before and after the treatment period were the maximum (Qmax) and average (Qave) urinary flow rates, and the percentage residual urine volume. Improvement was defined as a 25% decrease from baseline in IPSS, > 1 point increase in QOL score, and > 2.5 mL/s increase in Qmax. Adverse reactions potentially related to the study drugs were recorded throughout the treatment period. RESULTS: Both terazosin and tamsulosin produced statistically significant improvements in subjective and objective variables. Neither treatment affected systolic or diastolic blood pressure or pulse rate. Adverse reactions were noted in four patients (three in the terazosin group and one in the tamsulosin group). However, there was no statistically significant difference in the incidence of adverse effects between the groups. CONCLUSIONS: Despite the limitations of small sample size and relatively short treatment periods, terazosin and tamsulosin were equally effective in the treatment of symptomatic BPH in Japanese patients, using relatively lower doses than those used in Western countries.

Adrenergic alpha-Antagonists↗
PubMed2000

Changes in contused lung volume and oxygenation in patients with pulmonary parenchymal injury after blunt chest trauma.

Although it is well known that pulmonary parenchymal injury impairs oxygenation, the relationship between hypoxemia and volume of the contused lung after blunt chest trauma remains unknown. We studied 23 blunt chest trauma patients who underwent thoracic computed tomography (CT) within 24 hours after admission and also underwent follow-up CT at 1-week intervals until abnormal lung findings disappeared. Contused lung volume was determined quantitatively by CT. CT findings of parenchymal injury were either a diffuse lesion that disappeared within 1 week (n = 9 patients, group 1), or a solitary lesion that remained a few weeks after resolution of the diffuse lesion (n = 14 patients, group 2). PaO2/FiO2 was positively correlated with the volume of contused lung during the first 24 hours in both groups, however, there was no significant correlation after 1 week after injury. Degree of impaired oxygenation is related to the volume of the diffuse lesion that is recognized soon after injury.

Adolescent↗