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K Yoshida

Publications and source records attributed to K Yoshida.

At least 199 records · Page 11Linked to original sources
PubMed2001

Chirality organization of ferrocenes bearing podand dipeptide chains: synthesis and structural characterization.

A variety of ferrocenes bearing podand dipeptide chains have been synthesized to form an ordered structure in both solid and solution states and have been investigated by 1H NMR, FT-IR, CD, and X-ray crystallographic analyses. Conformational enantiomerization through chirality organization was achieved by the intramolecular hydrogen bondings between the podand dipeptide chains. The single-crystal X-ray structure determination of the ferrocene 2 bearing the podand dipeptide chains (-D-Ala-D-Pro-OEt) revealed two C2-symmetric intramolecular hydrogen bondings between CO (Ala) and NH (another Ala) of each podand dipeptide chain to induce the chirality-organized structure. The molecular structures of the ferrocene 1 composed of the podand L-dipeptide chains (-L-Ala-L-Pro-OEt) and 2 are in a good mirror image relationship, indicating that they are conformational enantiomers. An opposite helically ordered molecular arrangement was formed in the crystal packing of 2 as compared with 1. The ferrocene 2 exhibited induced circular dichroism (CD), which appeared at the absorbance of the ferrocene moiety. The mirror image of the CD signals between 1 and 2 was observed, suggesting that the chirality-organized structure via intramolecular hydrogen bondings is present even in solution. The ferrocene 4 bearing the podand dipeptide chains (-Gly-L-Leu-OEt) also showed an ordered structure in the crystal based on two intramolecular hydrogen bondings between CO (Gly) and NH (another Gly) of each podand dipeptide chain, together with intermolecular hydrogen bondings between CO adjacent to the ferrocene unit and NH (neighboring Leu) to create the highly organized self-assembly. A different self-assembly was observed in the crystal of the ferrocene 5 composed of the podand dipeptide chains (-Gly-L-Phe-OEt), wherein each molecule is bonded to two neighboring molecules through two pairs of symmetrical intermolecular hydrogen bonds to form a 14-membered intermolecularly hydrogen-bonded ring. These ordered structures based on the intramolecular hydrogen bondings in the solution state are also confirmed by 1H NMR and FT-IR.

Circular Dichroism↗
PubMed2001

DBTBS: a database of Bacillus subtilis promoters and transcription factors.

With the completion of the determination of its entire genome sequence, one of the next major targets of Bacillus subtilis genomics is to clarify the whole gene regulatory network. To this end, the results of systematic experiments should be compared with the rich source of individual experimental results accumulated so far. Thus, we constructed a database of the upstream regulatory information of B.subtilis (DBTBS). The current version was constructed by surveying 291 references and contains information on 90 binding factors and 403 promoters. For each promoter, all of its known cis-elements are listed according to their positions, while these cis-elements are aligned to illustrate their consensus sequence for each transcription factor. All probable transcription factors coded in the genome were classified with the Pfam motifs. Using this database, we compared the character of B.subtilis promoters with that of Escherichia coli promoters. Our database is accessible at http://elmo.ims.u-tokyo.ac.jp/dbtbs/.

Bacillus subtilis↗
PubMed2001

Increased T cell autoreactivity in the absence of CD40-CD40 ligand interactions: a role of CD40 in regulatory T cell development.

Mutations in the CD40 ligand (CD40L) gene lead to X-linked immunodeficiency with hyper-IgM, which is often associated with autoimmune diseases. To determine the contribution of defective CD40-CD40L interactions to T cell autoreactivity, we reconstituted CD40-CD40L interactions by transferring T cells from CD40-deficient mice to syngenic athymic nude mice and assessed autoimmunity. T cells from CD40-deficient mice triggered autoimmune diseases accompanied with elevations of various autoantibodies, while those from wild-type mice did not. In CD40-deficient mice, the CD25(+) CD45RB(low) CD4(+) subpopulation which regulates T cell autoreactivity was markedly reduced. CD40-deficient APCs failed to induce T regulatory cells 1 producing high levels of an inhibitory cytokine, IL-10 in vitro. Furthermore, autoimmune development was inhibited when T cells from CD40-deficient mice were cotransferred with CD45RB(low) CD4(+) T cells from wild-type mice or with T regulatory cells 1 induced on CD40-expressing APCs. Collectively, our results indicate that CD40-CD40L interactions contribute to negative regulation of T cell autoreactivity and that defective interactions can lead to autoimmunity.

Animals↗
PubMed2001

Development of fulminant hepatitis B (precore variant mutant type) after the discontinuation of low-dose methotrexate therapy in a rheumatoid arthritis patient.

A 75-year-old female rheumatoid arthritis patient who was positive for hepatitis B surface antigen and for antibodies to hepatitis Be antigen showed liver dysfunction, and therefore methotrexate (MTX) therapy was discontinued. Her drug lymphocyte stimulation test indicated positivity for MTX. Her liver dysfunction improved briefly, but she developed fulminant hepatitis with elevated levels of hepatitis B virus (HBV)/DNA polymerase and subsequently died. HBV/DNA analysis performed with polymerase chain reaction-mutation site-specific assay revealed that the fulminant hepatitis was caused by a precore mutant virus. Sudden reactivation of the immune system by discontinuation of MTX may have led to the attack on infected cells. Even when hepatitis Be antibodies are present, MTX should not be used in patients who have chronic infection with HBV.

Arthritis, Rheumatoid↗
PubMed2001

Expression of E1AF/PEA3, an Ets-related transcription factor in human non-small-cell lung cancers: its relevance in cell motility and invasion.

Cell invasion and metastasis characterize the malignant potential of non-small-cell lung cancers (NSCLCs). We have previously reported that E1AF, a member of the Ets-related transcription factor family, confers invasive phenotype on breast cancer and oral squamous-cell carcinoma cell lines. In our study, we analyzed the E1AF expression in cell lines and resected tumors of NSCLCs by Northern blot and in situ hybridization analyses and found that 15 of 17 cell lines and 12 of 19 tumors expressed E1AF mRNA while normal lung tissue and concomitant normal cells within tumors did not. To examine the biologic importance of E1AF in NSCLCs, we introduced the E1AF gene into VMRC-LCD and NCI-H226, NSCLC cell lines lacking E1AF expression, and examined cell motility and invasion activities. E1AF-transfected VMRC-LCD cells showed increased cell motility that was 2-fold that of parental and vector-transfected control cells (p < 0.01), and both cell motility and invasion were increased 1.6-fold in NCI-H226 (p < 0.01). Furthermore, hepatocyte growth factor (HGF), which is one of the most effective cell-scattering factors, stimulated the motile and invasive activities in E1AF-transfected VMRC-LCD and NCI-H226 cells but not in their parental or vector-transfected control cells. Ets-1 mRNA expression was found in E1AF-transfected VMRC-LCD cells but not in parental or vector-transfected cells. HGF further induced expression of the Ets-1 and urokinase-type plasminogen activator (uPA) genes specifically in E1AF-transfected cells. These findings suggest that E1AF plays a substantial role in the cell motility and invasion of NSCLCs.

Adenovirus E1A Proteins↗
PubMed2001

Effects of filler composition and surface treatment on the characteristics of opaque resin composites.

The effects of filler composition and surface treatment of titanium dioxide (TiO2) on the shear bond strength to noble metal and mechanical properties of opaque dental resin composites were assessed. A series of fillers for resin composites were prepared with untreated TiO2 or treated silica/alumina-coated TiO2 with silane coupling agent; these fillers were replaced with silanized SiO2 in increasing amounts. Each of various powder compositions were mixed with the liquid and applied to the surface of a silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy and light cured. A light-activated resin-veneering composite material was placed on top with the use of a brass ring mold and light cured. Specimens were stored at 37 degrees C in water for a period of 24 h. Additionally some specimens were thermocycled at 4 degrees C and 60 degrees C in water baths for 1 min each for 5000 cycles before shear mode testing was performed. Light-activated opaque resin composites containing filler with specific filler compositions of 50 wt% of untreated TiO2-50 wt% of silanized SiO2 (untreated TiO2(50)) and 40 wt% of untreated TiO2-60 wt% of silanized SiO2 (untreated TiO2(40)) showed higher shear bond strengths to the Ag-Pd-Cu-Au alloy than any other specific compositions when no thermocycling was involved. Surface treatment of TiO2 filler and TiO2(50)- and TiO2(40)-opaque resin composites prepared thereof showed significantly higher shear bond strengths than untreated TiO2(50)- and TiO2(40)-opaque resin composites when subjected to thermocycling. Surface-treated opaque resin composite had significantly higher compressive and flexural strength than untreated opaque resin composite after immersion in water for 1 month. Scanning electron microscopy of the fractured opaque resin composite surface showed an interface failure between TiO2 and the matrix resin for untreated composite, and cohesive failure within the resin for surface-treated composite. Surface-treated TiO2(50) and TiO2(40) may be clinically useful as the filler for light-activated opaque dental resin composites.

Adhesiveness↗
PubMed2001

7Li 2D CSI of human brain on a clinical scanner.

Lithium salts have been widely used in the treatment of mood disorders, but the mechanism of action is still not clear. In this work, a methodology for two-dimensional Lithium-7 imaging on clinical systems is presented. The data were acquired using a phosphorus volume head coil that was re-tuned for the Lithium-7 frequency. A spectroscopic sequence was used to acquire the free induction decay (FID) after volume excitation using a hard pulse. The results obtained on the head of patients undergoing lithium treatment (n = 7, 0.6 mEq/l average serum level) demonstrate that images of adequate signal to noise ratio (100:1) can be obtained in acceptable imaging times (55 min) using the proposed methodology. The distribution of 7Li appears uniform in the brains of the patients studied.

Brain↗
PubMed2001

An insulator element from the sea urchin Hemicentrotus pulcherrimus suppresses variation in transgene expression in cultured tobacco cells.

Specialized DNA sequences known as insulators protect genes from both the positive and negative influences of nearby chromatin. Many insulators have been identified in various species; however, few function in multiple species. We have shown that an insulator from the Ars (arylsulfatase) gene of the sea urchin Hemicentrotus pulcherrimus functions in plant cells. Normally, expression of an introduced chimeric GUS gene is inactivated in approximately 30% of transformed tobacco BY2 clones. Transgenes containing the Ars insulator, however, were expressed in all transformed tobacco BY2 cells. The insulator did not affect the copy number, the chromosomal position of transgene integration or maximum expression levels. These results suggest that the insulator functions to suppress the variation normally associated with transgene expression in tobacco BY2 cells.

Animals↗
PubMed2001

Establishment and characterization of tartrate-resistant acid phosphatase and alkaline phosphatase double positive cell lines.

Morphologically macrophage-like cells were cloned from hamster bone marrow cells by coculturing bone marrow cells with hamster chondrocytes. One of the clones (CCP-2) was characterized in the present study. CCP-2 cells were positive in an osteoclast marker enzyme, tartrate-resistant acid phosphatase (TRAP), alkaline phosphatase (ALP) and non-specific esterase (NSE). We showed CCP-2 cells degraded cartilage matrix and hydroxyapatite coated on Osteologic disks. A gelatinase secreted from CCP-2 cells was observed and purified from serum-free conditioned medium of the cells. N-terminal amino acid sequencing of the purified enzyme revealed it was matrix metalloproteinase-9. However, CCP-2 cells failed to express calcitonin receptors, a mature osteoclast marker, even after coculture with osteoblast ST2 cells in the presence of 1alpha, 25-dihydroxyvitamin D3 [1alpha, 25-(OH)2D3]. The cells showed high affinity to types X and I but not to type II collagen. In addition, histochemical studies have shown the presence of tartrate-resistant acid phosphatase and alkaline phosphatase double positive cells at the secondary ossification site of the hamster humerus. From these observations, we concluded that CCP-2 cells are similar to osteoclast but not the same. CCP-2 cells are therefore important tools for investigating chondroclastogenesis/osteoclastogenesis and endochondral ossification.

Acid Phosphatase↗
PubMed2001

Cause of death in renal transplant patients: a comparison between azathioprine and ciclosporin.

The results of renal transplantation have improved due to advances in immunosuppression techniques of preservation, and pre- and postoperative treatments; however, both morbidity and mortality remain serious problems. To decrease the morbidity and mortality rates we analyzed the causes of death after renal transplantation in our hospital. Between 1972 and 1999, we performed 364 renal transplantations, 257 of which were living-related and 107, cadaveric. There were 178 patients given azathioprine and 186 given ciclosporin. The survival rate of the patients on ciclosporin therapy was much better than that of those on azathioprine therapy. Of the total 364 renal transplant patients, 59 (16.2%) died, and 28 (47.5%) of these 59 deaths occurred within 1 year after renal transplantation. The causes of death were infection in 19 (32.2%) patients, gastrointestinal diseases in 16 (27.1%), cardiovascular diseases in 11 (18.6%), cerebrovascular diseases in 6 (10.2%), suicide in 3 (5.1%), and other causes in 4 (6.8%). These findings reinforce that early diagnosis and treatment are essential to decrease the morbidity and mortality rates assoiated with renal transplantation.

Azathioprine↗
PubMed2001

Treatment of unruptured intracranial aneurysms--a clinicopathological correlation.

OBJECT: Brain check-up is very important for detecting the incidence and prevalence of aneurysms in the population and to get the definite strategy for the treatment of intracranial aneurysms. METHODS: This is a retrospective study of 116 aneurysms detected by brain check-up between 1998-1999 which were treated either by clipping or endovascular coiling. In some cases the aneurysmal wall was resected for histopathological examination and compared with five normal autopsy cases. CONCLUSIONS: Direct surgery is the primary option for a patient with an aneurysm in the anterior circulation especially in young patients. Intravascular therapy is suitable for aneurysms in the posterior circulation and in intracavernous site.

Aged↗
PubMed2001

Monitoring of facial evoked EMG for hemifacial spasm: a critical analysis of its prognostic value.

Microvascular decompression (MVD) has come to stay as an effective way of treating hemifacial spasm. But it remains to be seen how much each of the electrophysiological monitoring techniques (intra-operative) are contributing to its increased efficacy. Their role as indicators for re-exploration or recurrence is to be evaluated with more studies. We have used the lateral spread response in those patients who had distinctly abnormal recording on the ipsilateral side, studied the intra-operative changes during MVD and correlated with the outcome of surgery. 38 patients operated for HFS, were selected for intra-operative monitoring of abnormal muscle responses. In 17 patients, there was persistence of abnormal muscle responses in the immediate postoperative period and only 6 of them had mild HFS. Two of 21 patients who had disappearance of abnormal responses had persistent mild HFS; but in all cases, the HFS disappeared within 3 months. So we found that the intra-operative recording was really not reliable in predicting the immediate postoperative outcome. However the outcome at 3 months suggested that waiting for some time before re-exploration is a better option, especially if the HFS had become mild.

Adult↗
PubMed2001

Establishment and characterization of macrophage-like cell lines expressing osteoclast-specific markers.

Osteoclasts differentiate from hematopoietic precursors of the monocyte/macrophage lineage to mononuclear preosteoclasts and multinuclear mature osteoclasts. In the present study, we report on the establishment of macrophage like cell lines from mouse bone marrow by coculturing bone marrow cells with mouse chondrocytes. Isolated clones (MLC-6 and MLC-7 cells) expressed fully differentiated osteoclast markers, such as calcitonin receptors, vitronectin receptors, tartrate-resistant acid phosphatase and vacuolar H+ -ATPase, in the absence of osteoclast differentiation factor/osteoprotegerin ligand/RANKL/TRANCE, which was essential for osteoclast differentiation. Most clones also maintained expression of a macrophage-associated protein, namely non-specific esterase. Both MLC-6 and MLC-7 cells released cathepsin K into the culture medium. Both clones resolved dentine slices when cocultured with the osteoblast cell line ST2. The cloned cell lines are considered to be useful tools in the study of osteoclast differentiation.

Animals↗
PubMed2001

Frequency and clinical features of patients with sensorineural hearing loss associated with the A3243G mutation of the mitochondrial DNA in otorhinolaryngic clinics.

The A3243G mutation of the mitochondrial gene is a cause of maternally inherited diabetes and deafness. The aim of this study was to evaluate the frequency and clinical features of this mutation in patients with sensorineural hearing loss (SNHL) in otorhinolaryngic clinics. The frequency of the A3243G mutation in 230 patients with SNHL was 1.74% (4/230). Three of the four patients had diabetes mellitus (DM) and were already aware that they had the mutation. The other had cardiomyopathy but not DM, and proved to have the mutation in this study. The frequency of the mutation was 12.9% (4/31) in patients with a family history of possible maternal inheritance of SNHL, 10.3% (3/29) in patients with DM, and 50% (3/6) in patients with both. The age of onset of SNHL in these patients and their families was between their teens and their forties. The chance of diagnosing the A3243G mutation in patients with SNHL in otorhinolaryngic clinics is probably less than 1%. Association of DM, cardiomyopathy, a family history of possible maternal inheritance of SNHL, and an onset of SNHL between the teens and the forties are signs suggesting the mutation. These signs provide us with a reason for genetic testing for the mutation.

Adolescent↗
PubMed2001

Validation of modeling approach to evaluate congener-specific concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans in air and soil near a solid waste incinerator.

A concise modeling approach using long-term averaged meteorological data was developed to estimate site-specific concentrations of congeners of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) near a solid waste incinerator. This approach consists of calculation of atmospheric dispersion, dry and wet deposition of gaseous and particle-bound congeners, and non-steady-state concentrations in soil. The predictability of this approach was evaluated by comparison of calculated concentrations of congeners in soil with those measured at eight locations near a municipal solid waste incinerator (MSWI). The variation of these concentrations due to variability of meteorological parameters is small. A considerable number of mean values show good agreement with measured concentrations within a factor of three. The reasonable agreement between calculated and measured concentrations indicates that algorithms for the calculation of vapor-phase deposition and non-steady-state concentrations in soil must be included in the modeling approach for an accurate estimation of the concentrations of congeners of PCDD/Fs emitted from MSWIs to the atmosphere. For a detailed estimation of site-specific concentrations, it is important to specify the bulk density of soil in the evaluated area, together with meteorological parameters.

Air Movements↗
PubMed2001

A giant internal carotid-posterior communicating artery aneurysm presenting with atypical trigeminal neuralgia and facial nerve palsy in a patient with autosomal dominant polycystic kidney disease: a case report.

BACKGROUND: In cases of internal carotid-posterior communicating artery (IC-PC) aneurysm, involvement of the trigeminal nerve at its root is rare, and facial nerve palsy is even more unusual. CASE REPORT: A large, unruptured IC-PC aneurysm was detected in a 56-year-old man with autosomal dominant polycystic kidney disease (ADPKD), but surgery was not performed because of mild renal dysfunction. Two months later, a sudden, severe headache suggested a subarachnoid hemorrhage, which was ruled out by computed tomography and lumbar puncture. Neurological examination revealed complete oculomotor palsy, atypical trigeminal neuralgia, and facial palsy with gustatory disturbance. Magnetic resonance (MR) imaging revealed a partially thrombosed giant aneurysm that directly compressed the trigeminal nerve root, reached the internal auditory canal, and was adjacent to the facial nerve. The neck of the aneurysm was successfully clipped via a subtemporal transtentorial approach. The postoperative course was uneventful, and all neurological symptoms had resolved within 3 months. CONCLUSIONS: We believe that the prosopalgia in this case was atypical trigeminal neuralgia due to direct compression of the trigeminal nerve root by the aneurysmal sac. A contributory cause was stretching of the oculomotor nerve, which contains sensory afferent inhibitory fibers derived from the ophthalmic branch of the trigeminal nerve. The facial palsy was of peripheral type and was accompanied by gustatory disturbance. This is the first reported case of facial palsy caused by an IC-PC aneurysm and also a very rare case of an IC-PC aneurysm clipped by a subtemporal transtentorial approach.

Carotid Artery Diseases↗
PubMed2001

Cerebral blood flow imaging in arteriovenous malformation complicated by normal perfusion pressure breakthrough.

BACKGROUND: A patient with normal perfusion pressure breakthrough (NPPB) after surgical removal of an arteriovenous malformation (AVM) was evaluated using single photon emission computed tomography cerebral blood flow (CBF) imaging. CASE DESCRIPTION: A 48-year-old man suffered consciousness disturbance because of an intraventricular hemorrhage and underwent ventricular drainage. Cerebral angiography showed a medium-sized AVM in the left parietal lobe. Three months after the ictus, a left parietal craniotomy was performed and total removal of the AVM was achieved. A brain region adjacent to the AVM with preoperative decreased vasoreactivity to acetazolamide showed marked hyperperfusion after AVM excision. Hemorrhage subsequently occurred in this area. CONCLUSION: CBF mapping seems to offer a noninvasive method for the preoperative identification of AVM patients at risk for NPPB, and to allow for early postoperative diagnosis of NPPB.

Blood Flow Velocity↗