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Biomedical subjects

T Okuno

Publications and source records attributed to T Okuno.

At least 19 recordsLinked to original sources
PubMed2006

An unusual renal vascular anomaly: common origin of arteries to the lower poles demonstrated by a computed tomography angiography using 16-slice multidetector computed tomography.

Arterial connection between the left and right kidneys is extremely rare. Only eight cases of such anomalous conditions have been reported in the world literature and all were confirmed by invasive angiography or dissection. We report a patient with this vascular anomaly clearly demonstrated by 16-slice multidetector computed tomography.

Angiography↗
PubMed2005

Ocular blood flow changes after dynamic exercise in humans.

PURPOSE: To investigate control mechanisms for ocular blood flow changes after dynamic exercise using two different methods. METHODS: Changes over time in the tissue blood flow in the retina and choroid-retina of healthy volunteers were determined after dynamic exercise (Master's double two-step test), using scanning laser Doppler flowmetry (SLDF) and laser speckle flowgraphy (LSFG). Changes in intraocular pressure (IOP), blood pressure, plasma CO(2) gas concentration (pCO(2)), and levels of nitric oxide (NO) metabolites were examined. RESULTS: Retinal blood flow measured by SLDF increased significantly only at 15 min after exercise. In contrast, normalized blur (NB) values in the choroid-retina, obtained by LSFG, increased significantly up to 60 min after exercise. Ocular perfusion pressure (OPP), calculated from IOP and blood pressure, increased significantly immediately and 15 min after exercise. The plasma NO metabolite levels increased significantly, although pCO(2) levels were unchanged. CONCLUSIONS: Dynamic exercise changes OPP and produces increased tissue blood flow in the retina in the immediate postexercise period, while blood flow increases more persistently in the choroid-retina. Difference in control of blood flow in these two regions may be related to stronger autoregulatory mechanism of blood flow in the retina. Nitric oxide may play a role in the regulation of blood flow.

Adult↗
PubMed2005

Synthesis of infectious in vitro transcripts from Cassia yellow blotch bromovirus cDNA clones and a reassortment analysis with other bromoviruses in protoplasts.

Cassia yellow blotch virus (CYBV), genus Bromovirus, was isolated from the Australian native legume, Cassia pleurocarpa, in western Queensland, and its host range was found to be distinct from other bromoviruses. In this study, CYBV was shown to infect systemically and efficiently a model plant species, Arabidopsis thaliana, as we recently reported for another bromovirus, Spring beauty latent virus (SBLV). We constructed full-length cDNA clones of CYBV genomic RNAs from which infectious in vitro transcripts can be transcribed, and determined their complete nucleotide sequences. CYBV RNA3 contains the box B motif in the intercistronic region, but lacks the subgenomic promoter-like sequence in the 5' noncoding region, as does Brome mosaic virus (BMV). To understand relationships among bromoviruses, we generated reassortants between CYBV and three other bromoviruses, BMV, SBLV and Cowpea chlorotic mottle virus. We found that all reassortants between BMV and CYBV accumulated viral RNAs to detectable levels in protoplasts of Nicotiana benthamiana, even when RNAs 1 and 2, which encode the replication proteins 1a and 2a, respectively, were heterologous. Sequence comparison and reassortment experiments of CYBV and other bromoviruses demonstrated that CYBV is closely related to BMV.

Bromovirus↗
PubMed2005

Coat protein-independent cell-to-cell movement of bromoviruses expressing brome mosaic virus movement protein with an adaptation-related amino acid change in the central region.

The movement protein (MP) of Brome mosaic virus (BMV) depends on the coat protein (CP) to mediate the cell-to-cell movement of BMV and CCMV(B3a), a recombinant Cowpea chlorotic mottle virus (CCMV) expressing BMV MP. Previous studies identified gain-of-function mutations in the central region of BMV MP that enable CCMV(B3a) to adapt to a resistant host. This study demonstrates that all adaptation-related MPs can partially or almost fully mediate the cell-to-cell movement of CCMV(B3a) and BMV without CP. Based on these results, we discuss adaptation mechanisms of CCMV(B3a) and the role of the central region of MP in the determination of virus movement mode.

Adaptation, Physiological↗
PubMed2004

Diurnal variation in microcirculation of ocular fundus and visual field change in normal-tension glaucoma.

PURPOSE: Diurnal variations in microcirculation of the ocular fundus in normal-tension glaucoma (NTG) were examined to compare with the normal control eyes. The correlation between progression of visual field impairment and diurnal variations in ocular circulation was also studied. METHODS: The subjects were 12 patients with NTG and 12 normal controls. Blood pressure (BP), intraocular pressure (IOP), ocular perfusion pressure (OPP), and square blur rate (SBR), an index of microcirculation acquired by the laser speckle method, were measured at 9 a.m. (morning), 3 p.m. (afternoon), and 9 p.m. (night). Diurnal variations in SBR were tested using the Friedman test and Wilcoxon signed ranks test. On the other hand, diurnal variations in BP, IOP, and OPP were tested by the analysis of variance. The visual field was evaluated at the same time as determining diurnal variation and again about 9 months later to calculate the change. The correlation between variation ratio in SBR and the change in visual field was examined by simple regression. RESULTS: A significant decrease (P=0.04) was found in SBR at night, as compared with the morning value, in the optic nerve head (ONH) of NTG, although no significant diurnal variations were found in SBR either in the choroid-retina or in normal control eyes. Other parameters showed no significant diurnal variations. The larger diurnal variation was in SBR of the ONH, and the more exacerbated visual field impairment was (r=0.59, P=0.04). CONCLUSION: These findings suggest that diurnal variations in the microcirculation of the ONH may play a role in the progression of NTG.

Aged↗
PubMed2004

Chromoendoscopy using indigo carmine dye spraying with magnifying observation is the most reliable method for differential diagnosis between non-neoplastic and neoplastic colorectal lesions: a prospective study.

BACKGROUND AND AIMS: Differential diagnosis between non-neoplastic and neoplastic lesions is very important at colonoscopy, since removal or biopsy of non-neoplastic polyps wastes time and resources. We therefore conducted a prospective study to examine whether indigo carmine dye spraying with and without magnification is more reliable than the conventional method for differential diagnosis. PATIENTS AND METHODS: 122 patients with 206 lesions of 10 mm or smaller were recruited into this study. All lesions detected on colonoscopy were first diagnosed using the conventional view, then at chromoendoscopy using 0.2 % indigo carmine, and finally at chromoendoscopy with magnification. The diagnosis at each step were recorded consecutively. All lesions were finally categorized as neoplastic or non-neoplastic according to pit pattern; non-neoplastic lesions were biopsied for histological evaluation, and all the neoplastic ones were removed endoscopically. The accuracy rate of each type of endoscopic diagnosis was evaluated, using histological findings as reference. RESULTS: Histologically, 46 lesions (22 %) were non-neoplastic and 160 (78 %) were neoplastic. The overall diagnostic accuracies by conventional view, chromoendoscopy, and chromoendoscopy with magnification were 84.0 % (173/206), 89.3 % (184/206) and 95.6 % (197/206), respectively. CONCLUSION: Chromoendoscopy with magnification is the most reliable method for determining whether a colorectal lesion is non-neoplastic or neoplastic.

Adult↗
PubMed2003

Complete nucleotide sequence of spring beauty latent virus, a bromovirus infectious to Arabidopsis thaliana.

Spring beauty latent virus (SBLV), a bromovirus, systemically and efficiently infected Arabidopsis thaliana, whereas the well-studied bromoviruses brome mosaic virus (BMV) and cowpea chlorotic mottle virus (CCMV) did not infect and poorly infected A. thaliana, respectively. We constructed biologically active cDNA clones of SBLV genomic RNAs and determined their complete nucleotide sequences. Interestingly, SBLV RNA3 contains both the box B motif in the intercistronic region, as does BMV, and the subgenomic promoter-like sequence in the 5' noncoding region, as does CCMV. Sequence comparisons of SBLV, BMV, CCMV, and broad bean mottle virus demonstrated that SBLV is closely related to BMV and CCMV.

Arabidopsis↗
PubMed2003

The movement protein gene is involved in the virus-specific requirement of the coat protein in cell-to-cell movement of bromoviruses.

Brome mosaic virus (BMV) requires the coat protein (CP) for cell-to-cell movement whereas Cowpea chlorotic mottle virus (CCMV), from the same genus, does not. Chimeric viruses created by exchanging the movement protein (MP) gene between the viruses can move from cell to cell. We show that interference in CP expression impaired the movement of the chimeric CCMV with the BMV MP gene but not of the chimeric BMV with the CCMV MP gene. We thus conclude that the MP gene plays a crucial role in determination of the virus-specific CP requirement in bromovirus cell-to-cell movement.

Amino Acid Sequence↗
PubMed2003

[Surgically treated mucoepidermoid carcinoma in a 6-year-old boy; report of a case].

A 6-year-old boy was admitted to our hospital with a history of recurrent obstructive pneumonia and hemoptysis. A chest computed tomography (CT) showed atelectasis in the left lower lobe. Angiograpy, which was performed for the suspicion of pulmonary sequestration, showed no feeding artery and revealed bleeding from the bronchial artery in the left lower lobe. As hemoptysis would not stop, an emergency left lower lobectomy was performed. Macroscopic examination of the resected specimen revealed a mass measuring 20 x 15 x 17 mm in the S8 proximal lung parenchyma, bronchiectasis, and an abscess in the distal lung parenchyma. Histopathologic examination determined the tumor was a mucoepidermoid carcinoma. Immunohistochemical staining revealed some tumor cells were positive for CA 19-9. The child has not had a recurrence 3 years postoperatively.

Bronchial Neoplasms↗
PubMed2002

Low-dose ACTH therapy for West syndrome: initial effects and long-term outcome.

BACKGROUND: Most Japanese pediatric neurologists attempt other treatments before using adrenocorticotropic hormone (ACTH) therapy for West syndrome (WS), and even then, they use only a low-dose synthetic ACTH to avoid serious adverse effects. In this multi-institutional study, the authors analyzed the initial effects, adverse effects, and long-term outcome in patients treated with low-dose synthetic ACTH in Japan. METHODS: The medical records of 138 patients with WS, who were treated with low-dose synthetic ACTH therapy for the first time at the authors' institutions between 1989 and 1998, were analyzed. RESULTS: At the end of ACTH therapy, excellent effect on seizures was noted in 106 of 138 (76%) patients, good effect in 23 (17%), and poor effect in 9 (7%). Initial effects on EEG were excellent in 53 of 138 (38%) patients, good in 76 (55%), and poor in 9 (7%). As for seizure prognosis at the time of follow-up, 51 of 99 (52%) patients were seizure-free, whereas 48 (48%) patients had seizures. Mental outcome was normal in 6 of 98 (6%) patients, mild mental retardation in 16 (16%), moderate mental retardation in 26 (27%), and severe mental retardation in 50 (51%). The initial effects of ACTH on seizures and long-term outcome were not dose dependent (daily dosage 0.005 to 0.032 mg/kg, 0.2 to 1.28 IU/kg; total dosage 0.1 to 0.87 mg/kg, 4 to 34.8 IU/kg). The severity of adverse effects correlated with total dosage of ACTH, and the severity of brain volume loss due to ACTH correlated well with the daily dosage and total dosage of ACTH. CONCLUSION: Low-dose synthetic ACTH therapy is as effective for the treatment of WS as the higher doses used in previous studies. The dosage of synthetic ACTH used in the treatment of WS can be decreased as much as possible to avoid serious adverse effects.

Brain↗
PubMed2002

Interleukin-1beta and tumor necrosis factor-alpha induce chemokine and matrix metalloproteinase gene expression in human colonic subepithelial myofibroblasts.

BACKGROUND: Colonic subepithelial myofibroblasts may play a role in the inflammatory responses and in extracellular matrix (ECM) metabolism. In this study, we investigated the effects of interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha on chemokine (IL-8 and monocyte chemoattractant protein (MCP)-1) and ECM turnover (proliferation of subepithelial myofibroblasts, and secretion of ECM and matrix metalloproteinases (MMPs)) in colonic subepithelial myofibroblasts. METHODS: Human colonic subepithelial myofibroblasts were isolated using the method described by Mahida et al. Chemokine and MMP expressions were determined by ELISA and Northern blotting. Nuclear factor (NF)-kappaB and NF-IL6 DNA binding activities were evaluated by electrophoretic gel mobility shift assays (EMSA). RESULTS: IL-1beta and TNF-alpha did not affect the proliferation of subepithelial myofibroblasts, but stimulated the secretion of types I and IV collagens weakly. Unstimulated subepithelial myofibroblasts secreted a large amount of MMP-2, but a small amount of IL-8, MCP-1 and MMP-1. IL-1beta and TNF-alpha both induced a dose- and time-dependent increase in IL-8, MCP-1 and MMP-1 secretion, and weakly stimulated MMP-2 secretion. IL-1beta and TNF-alpha both rapidly evoked NF-kappaB DNA-binding activity. The inhibition of NF-kappaB activation markedly blocked both IL-1beta- and TNF-alpha-induced IL-8 and MCP-1 mRNA expression, but did not affect MMP-1 mRNA expression. CONCLUSIONS: These observations indicate that chemokine secretion and ECM metabolism are collectively regulated by the proinflammatory cytokines, IL-1beta and TNF-alpha, in colonic subepithelial myofibroblasts. Thus, colonic subepithelial myofibroblasts may play an important role in the pathophysiology of inflammation in the colon.

Base Sequence↗
PubMed2001

Rational design, discovery, and synthesis of a novel series of potent growth hormone secretagogues.

In the joint experimental and computational efforts reported here to obtain novel chemical entities as growth hormone secretagogues (GHSs), a small database of peptides and non-peptides known to have GHS activity was used to generate and assess a 3D pharmacophore for this activity. This pharmacophore was obtained using a systematic and efficient procedure, "DistComp", developed in our laboratory. The 3D pharmacophore identified was then used to search 3D databases to explore chemical structures that could be novel GHSs. A number of these were chosen for synthesis and assessment of their ability to release growth hormone (GH) from rat pituitary cells. Among the compounds tested, those with a benzothiazepin scaffold were discovered with micromolar activity. To facilitate lead optimization, a second program, a site-dependent fragment QSAR procedure was developed. This program calculates a library of chemical and physical properties of "fragments" or chemical components in a known pharmacophore and determines which, if any, of these properties are important for the observed activity. The combined use of the 3D pharmacophore and the results of the site-dependent fragment QSAR analysis led to the discovery and synthesis of a novel series of potent GHSs, a number of which had nanomolar in vitro activity.

Animals↗
PubMed2001

Contribution of enzymic alpha, gamma-elimination reaction in detoxification pathway of selenomethionine in mouse liver.

The objective of this study was to clarify the detoxification pathways of selenomethionine (SeMet) in mouse liver. It has been postulated that SeMet may be metabolized to selenocysteine (SeCyH) via a pathway similar to methionine (Met). CySeH may be decomposed to H(2)Se, which is consequently methylated to CH(3)SeH, (CH(3))(2)Se, and (CH(3))(3)Se(+). In this study, we estimated that the median lethal single oral dose (LD(50)) was 67.0 mg/kg. We also found that (CH(3))(3)Se(+) was quickly produced in mouse liver after single oral administration of SeMet. This result suggested the existence of a quick alpha,gamma-elimination pathway. We measured the amounts of alpha-ketobutyrate, NH(3), and CH(3)SeH produced by enzymic alpha,gamma-elimination reaction of SeMet in the liver of periodate-oxidized adenosine (PAD) or D,L-propargylglycine (PPG)-treated mice in order to verify the existence of alpha,gamma-elimination enzyme. PAD is an inhibitor of S-adenosylhomocysteinase (EC 3.3.1.1), which is necessary for conversion of SeMet to SeCyH. PPG is an effective inhibitor of the pyridoxal 5'-phosphate (PLP)-containing enzyme bacterial L-methionine gamma-lyase (EC 4.4.1.11) contributing to the alpha,gamma-elimination reaction of SeMet and cystathionine gamma-lyase (EC 4.4.1.1) relating to conversion of SeMet to SeCyH. When SeMet was incubated with the S9 fraction from liver of PAD-treated mice, the formation of alpha-ketobutyrate was much the same as that from nontreated mouse liver. However, the amount of alpha-ketobutyrate formed significantly decreased in the reaction of SeMet with S9 fraction from the liver of PPG-treated mice. In an in vivo experiment using mice treated with PAD before a toxic dosage of SeMet, the amount of SeMet in the liver decreased and the amount of acid-volatile Se derived from CH(3)SeH increased gradually. This phenomenon was not observed in the PPG-pretreated group. Furthermore, the protein fraction that had the alpha,gamma-elimination enzyme activity was found in mouse liver cytosol by gel chromatographic technique. The results of this study indicated that SeMet was directly metabolized to CH(3)SeH by an alpha,gamma-elimination enzyme analogous to bacterial L-methionine gamma-lyase, in addition to the generally acceptable pathway via SeCyH.

Ammonia↗
PubMed2001

Crystallization and preliminary X-ray study of endopolygalacturonase from the pathogenic fungus Stereum purpureum.

Crystals of endopolygalacturonase I from Stereum purpureum have been obtained by the vapour-diffusion method. Prior to crystallization work, endopolygalacturonase I was deglycosylated with endo-beta-N-acetylglucosaminidase H. The crystal diffracts to ultrahigh (0.96 A) resolution using synchrotron radiation and belongs to space group P1, with unit-cell parameters a = 37.26, b = 46.34, c = 52.05 A, alpha = 67.17, beta = 72.44, gamma = 68.90 degrees.

Basidiomycota↗
PubMed2001

Application of 2-aminopyridine fluorescence labeling in the analysis of in vivo and in vitro metabolism of dextran sulfate sodium by size-exclusion high-performance liquid chromatography.

The present study describes a size-exclusion high-performance liquid chromatographic method for the separation and quantification of sulfated polysaccharides, such as dextran sulfate sodium (DSS). Pyridylamination of DSS was achieved without difficulty using 2-aminopyridine as a fluorometric label. In addition, 0.1-0.2 M phosphate buffer (pH 3.0) was found to be the mobile phase which produced the best separation. In vitro enzymatic degradation of the pyridylamino-DSS (PA-DSS5000, Mr 5000) using alpha-amylase and the in vivo metabolism in the rat feces after oral administration of PA-DSS5000 were then evaluated. Two small peaks of approximately Mr 380 and 600 appeared after co-incubation with alpha-amylase, indicating PA-DSS5000 may be considerably depolymerized. In vivo, however, PA-DSS5000 excreted in the feces was mainly of PA-DSS5000 polymer. No peaks of less than Mr 5000 were not clearly detectable in the feces because of background fluorescence attributable to gut lumen contents. This method of fluorometric analysis allows fairly selective detection of sulfated polysaccharides in biological materials.

Aminopyridines↗
PubMed2001

Activation of latent Kaposi's sarcoma-associated herpesvirus by demethylation of the promoter of the lytic transactivator.

Kaposi's sarcoma-associated herpesvirus (KSHV) is strongly linked to Kaposi's sarcoma, primary effusion lymphomas, and a subset of multicentric Castleman's disease. The mechanism by which this virus establishes latency and reactivation is unknown. KSHV Lyta (lytic transactivator, also named KSHV/Rta), mainly encoded by the ORF 50 gene, is a lytic switch gene for viral reactivation from latency, inasmuch as it is both essential and sufficient to drive the entire viral lytic cycle. Here we show that the Lyta promoter region was heavily methylated in latently infected cells. Treatment of primary effusion lymphoma-delivered cell lines with tetradecanoylphorbol acetate caused demethylation of the Lyta promoter and induced KSHV lytic phase in vitro. Methylation cassette assay shows demethylation of the Lyta promoter region was essential for the expression of Lyta. In vivo, biopsy samples obtained from patients with KSHV-related diseases show the most demethylation in the Lyta promoter region, whereas samples from a latently infected KSHV carrier remained in a methylated status. These results suggest a relationship among a demethylation status in the Lyta promoter, the reactivation of KSHV, and the development of KSHV-associated diseases.

DNA Methylation↗
PubMed2001

Pyrrolidine inhibitors of human cytosolic phospholipase A2. Part 2: synthesis of potent and crystallized 4-triphenylmethylthio derivative 'pyrrophenone'.

We synthesized a potent and crystallized human cytosolic phospholipase A2alpha inhibitor, pyrrophenone (6) which inhibits the isolated enzyme with an IC50 value of 4.2 nM. Pyrrophenone shows potent inhibition of arachidonic acid release, prostaglandin E2, thromboxane B2, and leukotriene B4 formation in human whole blood. The magnitudes of prostaglandin E2 and thromboxane B2 inhibition are the same as those of indomethacin.

Arachidonic Acid↗