Biomedical subjects

T Nonaka

Publications and source records attributed to T Nonaka.

At least 19 recordsLinked to original sources

PubMed2007

In vitro activation of the corticosteroid ciclesonide in animal nasal mucosal homogenates.

Ciclesonide, a new corticosteroid for allergic rhinitis, is administered as an inactive parent compound that is converted by esterases to the pharmacologically active metabolite, desisobutyryl-ciclesonide (des-CIC). This study investigated the in vitro activation of ciclesonide in nasal mucosa of multiple animal species. Nasal mucosal homogenates from rats, guinea-pigs, rabbits and dogs were incubated with ciclesonide 0.5 micromol/l (0.271 microg/ml) or 5 micromol/l (2.71 microg/ml) for up to 120 min. Concentrations of ciclesonide and des-CIC were measured by high-performance liquid chromatography with tandem mass spectrometry. Ciclesonide was metabolized to des-CIC in nasal mucosal homogenates of each species. The initial velocities of des-CIC formation ranged from 0.0038 to 0.0150 nmol/min/mg protein and 0.0319 to 0.0983 nmol/min/mg protein in nasal mucosal homogenates incubated with ciclesonide 0.5 micromol/l and 5 micromol/l, respectively. Furthermore, the initial velocities of ciclesonide metabolism ranged from 0.0032 to 0.0142 nmol/min/mg protein and 0.0445 to 0.1316 nmol/min/mg protein in nasal mucosal homogenates incubated with ciclesonide 0.5 micromol/l and 5 micromol/l, respectively. This study confirms that ciclesonide is converted to des-CIC in nasal mucosal homogenates without any marked differences among animal species.

Adrenal Cortex Hormones↗

PubMed2006

Efficient correction of Fabry mice and patient cells mediated by lentiviral transduction of hematopoietic stem/progenitor cells.

A deficiency in alpha-galactosidase A (alpha-gal A) activity causes Fabry disease. Virus-based delivery of genes can correct cells and establish a sustained supply of therapeutic proteins. Recombinant lentiviral vectors (LVs) show promise in this context. We first demonstrate LV-mediated marking of peripheral blood (PB) cells by transduction/transplantation of hematopoietic stem/progenitor cells. Stable enGFP expression was observed in PB for 37 weeks. Next, we transplanted Fabry mice with bone marrow mononuclear cells (BMMNCs) transduced a single time with a LV encoding the human alpha-gal A cDNA. Sustained expression of functional alpha-gal A in Fabry mice was observed over 24 weeks. Plasma alpha-gal A activity from treated Fabry mice was two-fold higher than wild-type controls. Increased alpha-gal A activity, often to supra-normal levels, and reduction of globotriaosylceramide, a glycolipid that accumulates in Fabry disease, was observed in all organs assessed. In secondary bone marrow transplantations, Fabry mice showed multilineage marking of PB, splenocytes and BMMNCs, along with therapeutic levels of alpha-gal A activity in plasma and organs over 20 weeks. Lastly, we transduced mobilized PB CD34(+) cells from a Fabry patient and observed corresponding enzymatic increases. Thus a single LV-mediated transduction of primitive hematopoietic cells can result in sustained correction for Fabry disease.

Animals↗

PubMed2006

Aspirin resistance detected with aggregometry cannot be explained by cyclooxygenase activity: involvement of other signaling pathway(s) in cardiovascular events of aspirin-treated patients.

OBJECTIVES: Although the concept of aspirin resistance is extensively reported in medical literature, its precise mechanisms and clinical outcomes are largely unknown. In this study, we examined individual thromboxane biosynthesis and platelet aggregation in aspirin-treated patients, and whether the results of a platelet aggregation test influenced clinical outcomes. RESULTS: Subjects taking 81 mg of aspirin (n = 50) and controls (n = 38) were evaluated for platelet aggregation and platelet cyclooxygenase-1 (COX-1) activity by measuring collagen-induced thromboxane B2 production. For aggregometry, both light transmission (LT) and laser-light scattering methods were employed to quantitatively evaluate aggregate sizes and numbers. Aspirin treatment resulted in the inhibition of collagen-induced platelet aggregation, particularly the transition from small to large platelet aggregates. Although platelet COX-1 activity seemed to be uniformly inhibited in all patients, platelet aggregation studies showed great inter-individual differences; variation in platelet COX-1 activity only accounted for 6-20% of the individual aggregations. Factor analysis revealed the existence of a common factor (other than platelet COX-1) that explained 48.4% of the variations in platelet aggregation induced by collagen, adenosine diphosphate (ADP), and collagen-related peptide. We then prospectively enrolled 136 aspirin-treated patients in our study, and we found that being in the upper quartile level of LT, or with large aggregate formation induced by collagen, was an independent risk factor for developing cardiovascular events within 12 months [hazard ratio (HR) = 7.98, P = 0.008 for LT; HR = 7.76, P = 0.007 for large aggregates]. On the other hand, the existence of diabetes mellitus was an independent risk factor for overall outcomes (HR 1.30-11.9, P = 0.015-0.033). CONCLUSIONS: Aspirin resistance expressed as unsuppressed platelet COX-1 activity is a rare condition in an out-patient population. Other factor(s) affecting collagen-induced platelet aggregation may influence early outcomes in aspirin-treated patients.

Aged↗

PubMed2005

Heat shock protein 90 (Hsp90) chaperone complex inhibitor, radicicol, potentiated radiation-induced cell killing in a hormone-sensitive prostate cancer cell line through degradation of the androgen receptor.

Until now, there has not been enough information on how androgens or androgen deprivation may influence the response of cancer cells to radiation. In this study, the effect of dihydrotestosterone (DHT) on cellular proliferative activity and radiosensitivity was examined in a hormone-sensitive human prostate cancer cell line, LNCaP. In addition, the study also examined how a heat shock protein 90 (Hsp90) chaperone complex inhibitor modified the effect of DHT on the radiosensitivity of the cells, because binding of the androgen receptor (AR) to Hsp90 is required to maintain the stability and functioning of AR. The hormone-sensitive human prostate cancer cell line, LNCaP, was used. Radicicol was used as one of the known Hsp90 chaperone complex inhibitors, and the cells were incubated in the presence of this compound at a concentration of 500 nM. Cellular radiosensitivity was determined by the clonogenic assay; the changes in the protein expression were examined by Western blotting or immunofluorescence. DHT at a concentration of 1 nM caused enhancement of the proliferative activity and reduction of the radiosensitivity of the cells. Radicicol at a concentration of 500 nM abolished the DHT-induced decrease in cellular radiosensitivity and potentiated the radiation-induced cell killing synergistically. Consistent with the changes in the cellular radiosensitivity, radicicol degraded AR, Raf-1 and HER2/neu via reduced binding of AR to Hsp90, although selective degradation of HER2/neu caused by Herceptin, a monoclonal antibody against HER2, did not affect the cellular radiosensitivity. The results suggest that the Hsp9O chaperone complex may be a potential molecular target for potentiation of radiation-induced cell killing in a hormone-sensitive prostate cancer cell line.

Androgens↗

PubMed2005

[Castleman disease of the inter-lobar lymph node origin].

We report a case of Castleman disease which originated from the inter-lobar lymph node, with a review of literatures. A 19-year-old woman complaining of cough was pointed out to have an abnormal shadow in the left lung field on chest X-ray. Chest computed tomography (CT) and magnetic resonance imaging (MRI) with enhancement revealed a homogeneous mass lesion at the left inter-lobar portion of the lung. Bronchoscopic findings demonstrated mucosal telangiectasis of the left lower bronchus. We performed the usual axillary thoracotomy and succeeded in extirpation of the tumor without large amount of bleeding. The tumor was elastic and hard, and 70 x 55 x 45 mm in size. Her postoperative course was uneventful and she was discharged on the 12th postoperative day.

Adult↗

PubMed2004

Frontotemporal dementia with Pick-type histology associated with Q336R mutation in the tau gene.

In this report, we describe the clinical and neuropathological features of a case of familial frontotemporal dementia (FTD), with onset at 58 years of age and disease duration of 10 years, associated with a novel mutation, Q336R, in the tau gene (tau). In vitro studies concerning the properties of tau proteins bearing this mutation, with respect to microtubule assembly and tau filament aggregation, are reported. Clinically, the patient showed alterations in memory, language and executive functions and marked behavioural change consistent with FTD, although the extent of memory impairment was more than is characteristic of FTD. At autopsy, there was degeneration of the frontal and temporal lobes associated with the presence of hyperphosphorylated tau proteins in swollen (Pick) cells and intraneuronal inclusions (Pick bodies). By immunohistochemistry, the Pick bodies contained both 3-repeat and 4-repeat tau proteins although, because no fresh tissues were available for analysis, the exact isoform composition of the aggregated tau proteins could not be determined. Neurons within frontal cortex contained neurofibrillary tangle-like structures, comprising both straight and twisted tubules, or Pick bodies in which the filaments were short and randomly orientated. In vitro, and in common with other tau missense mutations, Q336R caused an increase in tau fibrillogenesis. However, in contrast to most other tau missense mutations, Q336R increased, not decreased, the ability of mutant tau to promote microtubule assembly. Nonetheless, this latter functional change may likewise be detrimental to neuronal function by inducing a compensatory phosphorylation that may yield increased intracellular hyperphosphorylated tau species that are also liable to fibrillize. We believe the mutation is indeed pathogenic and disease causing and not simply a coincidental rare and benign polymorphism. Since this mutation is segregating with the FTD clinical and neuropathological phenotype, it has not been found in unaffected individuals and it has novel functional properties in vitro which are likely to be detrimental to neuronal function in vivo.

Aged↗

PubMed2004

Studies on solution and solution-cast film of polyaniline colloids prepared in the absence and presence of ultrasonic irradiation.

Spectroscopic and voltammetric features for the solution and solution-cast film of polyaniline (PANI) colloids prepared in the absence and presence of ultrasonic irradiation were examined. Significant differences in the color and absorption spectra between the solution of colloids prepared in the absence and presence of irradiation were observed. Effects of ambient atmosphere on the solution of colloids were also studied. A gradual decay in the absorption at approximately 365 nm was occurred upon ageing the solution in air for the colloid prepared under ultrasonic irradiation. PANI film, cast from its colloidal solution, exhibited excellent electroactivity. The films thus cast were applied to electrode modification to control electrochemical reaction. Clear voltammetric response was observed on the electrode modified with the colloid prepared in the presence of ultrasonic irradiation.

Journal Article↗

PubMed2004

Radicicol potentiates heat-induced cell killing in a human oesophageal cancer cell line: the Hsp90 chaperone complex as a new molecular target for enhancement of thermosensitivity.

PURPOSE: To examine the ability of a heat shock protein 90 (Hsp90) chaperone complex inhibitor, radicicol, to modify thermal response and heat-induced cell killing, and to clarify the underlining mechanisms. MATERIALS AND METHODS: A human oesophageal cancer cell line (TE-1), with a mutant p53 gene, was used. To examine the effect of radicicol on heat-induced cell killing, radicicol at a concentration of 100 nM was incubated with the cells for 7 h during heat treatment. Changes in the expression of proteins were examined by Western blot and immunofluorescence analysis. RESULTS: Radicicol in combination with heat synergistically potentiated heat-induced cellular killing despite an increase in the expression of Hsp72 and Hsp27 caused by radicicol. Heat alone activated Raf-1 and p42/p44 extracellular signal-regulated kinase (Erk), and heat in combination with radicicol inhibited the activation of Raf-1 and p42/p44 Erk through reduced binding of Raf-1 to Hsp90. Phosphorylation of Akt was also decreased by radicicol. CONCLUSIONS: The Hsp90 chaperone complex inhibitor, radicicol, potentiated heat-induced cellular killing, and inhibition of p42/p44 Erk and Akt activation rather than modification of Hsp expression might be involved in enhancing cellular thermosensitivity. Results suggest that the Hsp90 chaperone complex could be a new molecular target for the modification of the cellular response to heat.

Cell Line, Tumor↗

PubMed2004

[Evaluation of sternal deformity after pediatric minimally invasive cardiac surgery].

Sternal shape is one of the most important esthetic factors of the chest appearance after pediatric minimally invasive cardiac surgery (pMICS) as well as length of skin wound. We evaluated the grade of postoperative sternal deformity in 20 patients who underwent total repair of pediatric congenital heart disease [atrial septal defect (ASD): 17, ventricular septal defect (VSD): 2, partial anomalous pulmonary venous connection (PAPVC): 1] with minimal skin incision and lower partial median sternotomy. The sternum was closed with stainless wire in 3 patients, with absorbable polydioxanone (PDS) cord in 5 patients, with combined use of reabsorbable radiolucent poly (L-lactate) acid sternal pin and absorbable PDS cord in 12 patients. The evaluation of postoperative sternal deformity was made according to the vertebral index (VI) and frontosagittal index (FSI) in 3 groups with each sternal closure method. VI and FSI of the 3 groups showed no significant difference. Sternal deformity in the group with sternal closure with PDS cord group was more severe than that in other 2 groups. The combined use of sternal pin with PDS cord offered the most sufficient fixative strength for sternal closure.

Absorbable Implants↗

PubMed2003

Pharmacoepidemiologic investigation of a clonazepam-valproic acid interaction by mixed effect modeling using routine clinical pharmacokinetic data in Japanese patients.

Non-linear Mixed Effects Modeling (NONMEM) was used to estimate the effects of clonazepam-valproic acid interaction on clearance values using 576 serum levels collected from 317 pediatric and adult epileptic patients (age range, 0.3-32.6 years) during their clinical routine care. Patients received the administration of clonazepam and/or valproic acid. The final model describing clonazepam clearance was CL = 144.0 TBW-0.172 1.14VPA, where CL is total body clearance (mL/kg/h); TBW is total body weight (kg); VPA = 1 for concomitant administration of valproic acid and VPA = zero otherwise. The final model describing valproic acid clearance was CL (mL/kg/h) = 17.2 TBW-0.264 DOSE0.159 0.821CZP 0.896GEN, where DOSE is the daily dose of valproic acid (mg/kg/day); CZP = 1 for concomitant administration of clonazepam and CZP = zero otherwise; GEN = 1 for female and GEN = zero otherwise. Concomitant administration of clonazepam and valproic acid resulted in a 14% increase in clonazepam clearance, and a 17.9% decrease in valproic acid clearance.

Adolescent↗

PubMed2003

Clinical results of aortic arch replacement using a four branched prosthetic graft.

AIM: The aim of this study was to evaluate the operative techniques of total arch replacement, the clinical results and the survival curves of patients following this procedure. METHODS: Since December 2001, 92 patients have undergone surgical treatment for aortic dissection and aneurysm. The total aortic arch replacement was performed in 24 of these patients. There were 16 men and 8 women, and the age range was 42 to 81 years with a mean age of 59.4 years. As the operative technique for total arch replacement, we used the 4-branched prosthetic graft, selective cerebral perfusion (SCP), continuous cold blood cardioplegia (CCBC), and open distal anastomosis under circulatory arrest. The combined operations were coronary bypass grafting in 4 patients, aortic valve suspension in 1 patient and a Bentairs procedure in 1 patient. Eleven (73.3%) patients with acute dissection required emergency operation. RESULTS: The hospital mortality rate was 25% (6 of the 24 patients). The causes of death were multiple organ failure (MOF) due to renal and mesenteric ischemia in 3 patients, cerebral infarction in 2 patients, myonephropathic metabolic syndrome (MNMS) in 1 patient, respectively. The data concerning extracorporeal circulation was 204+/-53 min in total pump time, 136+/-43 min in aortic cross clamp time, 83+/-14 min in SCP time and 48+/-10 min in circulatory arrest time, respectively. The long-term result in actuarial survival rate was 76% for 5 years. CONCLUSION: We consider the technique of total arch replacement using 4-branched prosthetic graft, SCP, CCBC, and open distal anastomosis is a useful operative method in patients with aortic aneurysm.

Adult↗

PubMed2001

Roles of the exposed aromatic residues in crystalline chitin hydrolysis by chitinase A from Serratia marcescens 2170.

Four exposed aromatic residues, two in the N-terminal domain (Trp-69 and Trp-33) and two in the catalytic domain (Trp-245 and Phe-232) of Serratia marcescens chitinase A, are linearly aligned with the deep catalytic cleft. To investigate the importance of these residues in the binding activity and hydrolyzing activity against insoluble chitin, site-directed mutagenesis to alanine was carried out. The substitution of Trp-69, Trp-33, or Trp-245 significantly reduced the binding activity to both highly crystalline beta-chitin and colloidal chitin. The substitution of Phe-232, which is located closest to the catalytic cleft, did not affect the binding activity. On the other hand, the hydrolyzing activity against beta-chitin microfibrils was significantly reduced by the substitution of any one of the four aromatic residues including Phe-232. None of the mutations reduced the hydrolyzing activity against soluble substrates. These results clearly demonstrate that the four exposed aromatic residues are essential determinants for crystalline chitin hydrolysis. Three of them, two in the N-terminal domain and one in the catalytic domain, play vital roles in the chitin binding. Phe-232 appeared to be important for guiding the chitin chain into the catalytic cleft. Based on these observations, a model for processive hydrolysis of crystalline chitin by chitinase A is proposed.

Base Sequence↗

PubMed2001

Enolase, a cellular glycolytic enzyme, is required for efficient transcription of Sendai virus genome.

Cellular proteins (host factors) may play key roles in transcription of Sendai virus (SeV) genome. We have previously shown that the host factor activity, which stimulates in vitro mRNA synthesis of SeV, from bovine brain comprises at least three complementary factors, and two of them were identified as tubulin and phosphoglycerate kinase (PGK). Here the third host factor activity was further resolved into two complementary factors, and one of them was purified to an almost single polypeptide chain with an apparent M(r) of 52,000 (p52) and was identified as a glycolytic enzyme, enolase. Recombinant human alpha-enolase, as did p52, acted synergistically with other three host factors to stimulate SeV mRNA synthesis. West-Western blot analysis demonstrated that tubulin specifically binds enolase as well as PGK, suggesting that these two glycolytic enzymes regulate SeV transcription through their interactions with tubulin.

Alcaligenes↗

PubMed2001

Shigella protein IpaH(9.8) is secreted from bacteria within mammalian cells and transported to the nucleus.

Various pathogenic bacteria such as Shigella deliver effector proteins into mammalian cells via the type III secretion system. The delivered Shigella effectors have been shown to variously affect host functions required for efficient bacterial internalization into the cells. In the present study, we investigated the IpaH proteins for their ability to be secreted via the type III secretion system and their fate in mammalian cells. Upon incubation in a medium containing Congo red, the bacteria secrete IpaH into the medium, but secretion of IpaH occurs later than that of IpaBCD. Immunofluorescence microscopy indicated that IpaH(9.8) is secreted from intracellular bacteria and transported into the nucleus. On microinjection of the protein, intracellular IpaH(9.8) is accumulated at one place around the nucleus and transported into the nucleus. This movement seems to be dependent on the microtubule network, since nuclear accumulation of IpaH(9.8) is inhibited in cells treated with microtubule-destabilizing agents. In nuclear import assay, IpaH(9.8) was efficiently transported into the nucleus, which was completely blocked by treatment with wheat germ agglutinin. The nuclear transport of IpaH(9.8) does not depend on host cytosolic factors but is partially dependent on ATP/GTP, suggesting that, like beta-catenin, IpaH(9.8) secreted from intracellular Shigella can be transported into the nucleus.

Amino Acid Sequence↗

PubMed2001

Suppression of inflammatory and neuropathic pain symptoms in mice lacking the N-type Ca2+ channel.

The importance of voltage-dependent Ca2+ channels (VDCCs) in pain transmission has been noticed gradually, as several VDCC blockers have been shown to be effective in inhibiting this process. In particular, the N-type VDCC has attracted attention, because inhibitors of this channel are effective in various aspects of pain-related phenomena. To understand the genuine contribution of the N-type VDCC to the pain transmission system, we generated mice deficient in this channel by gene targeting. We report here that mice lacking N-type VDCCs show suppressed responses to a painful stimulus that induces inflammation and show markedly reduced symptoms of neuropathic pain, which is caused by nerve injury and is known to be difficult to treat by currently available therapeutic methods. This finding clearly demonstrates that the N-type VDCC is essential for development of neuropathic pain and, therefore, controlling the activity of this channel can be of great importance for the management of neuropathic pain.

Acetic Acid↗

PubMed2001

Genistein, a tyrosine kinase inhibitor, enhanced radiosensitivity in human esophageal cancer cell lines in vitro: possible involvement of inhibition of survival signal transduction pathways.

PURPOSE: The effect of genistein, a tyrosine kinase inhibitor, on radiosensitivity was examined, especially focusing on "survival signal transduction pathways." METHODS AND MATERIALS: Two human esophageal squamous cell cancer cell lines, TE-1 (p53, mutant) and TE-2 (p53, wild), were used. Radiosensitivity was determined by clonogenic assay, and activation of survival signals was examined by Western blot. RESULTS: Genistein (30 microM) greatly enhanced radiosensitivity in these cell lines by suppressing radiation-induced activation of survival signals, p42/p44 extracellular signal-regulated kinase and AKT/PKB. Significant increase in the percentage of apoptotic cells and increased poly[ADP-ribose] polymerase cleavage were observed in TE-2, but not in TE-1 even after combination of genistein with irradiation. In terms of changes in expression of p53-related proteins, increase in expression of Bax and decrease in that of Bcl-2 were observed in TE-2 but not in TE-1, suggesting that the main mode of cell death induced by genistein in a cell line with wild type p53 differed from that with mutant p53. CONCLUSIONS: This study suggested that survival signals, including p42/p44 ERK and AKT/PKB, may be involved in determining radiosensitivity, and genistein would be a potent therapeutic agent that has an enhancing effect on radiation.

Apoptosis↗

PubMed2001

Crystallization and preliminary X-ray diffraction studies of a novel alkaline serine protease (KP-43) from alkaliphilic Bacillus sp. strain KSM-KP43.

A novel alkaline serine protease (KP-43) which belongs to a new class of the subtilisin superfamily was crystallized by the sitting-drop vapour-diffusion method with ammonium sulfate as a precipitant. The crystals belong to the orthorhombic space group C222(1), with unit-cell parameters a = 43.50 (2), b = 110.4 (1), c = 168.9 (1) A. The crystals diffract X-rays beyond 1.9 A resolution using Cu Kalpha radiation from a rotating-anode generator and are suitable for high-resolution crystal structure analysis.

Bacillus↗

PubMed2001

Trp122 and Trp134 on the surface of the catalytic domain are essential for crystalline chitin hydrolysis by Bacillus circulans chitinase A1.

From the 3D-structural analysis of the catalytic domain of chitinase A1, two exposed tryptophan residues (W122 and W134) are proposed to play an important role in guiding a chitin chain into the catalytic cleft during the crystalline chitin hydrolysis. Mutation of either W122 or W134 to alanine significantly reduced the hydrolyzing activity against highly crystalline beta-chitin microfibrils. Double mutation almost completely abolished the hydrolyzing activity. On the other hand, the hydrolyzing activity against either soluble or amorphous substrate was not reduced. These mutations slightly impaired the binding activity of this enzyme. These results clearly demonstrated that the two exposed aromatic residues play a critical role in hydrolyzing the chitin chain in crystalline chitin.

Bacillus↗