Biomedical subjects

Tetsuo Yoshida

Publications and source records attributed to Tetsuo Yoshida.

7 recordsLinked to original sources

PubMed2004

Variants of the orexin2/hcrt2 receptor gene identified in patients with excessive daytime sleepiness and patients with Tourette's syndrome comorbidity.

The orexin-2/hypocretin-2 (OX2R) receptor gene is mutated in canine narcolepsy and disruption of the prepro-orexin/hypocretin ligand gene results in both an animal model of narcolepsy and sporadic cases of the human disease. This evidence suggests that the structure of the OX2R gene, and its homologue, the OX1R gene, both members of the G protein-coupled receptor (GPCR) family, and the gene encoding the peptide ligands, the prepro-orexin/hypocretin gene, may be variables in the etiology of sleep disorders. We report a single stranded conformational polymorphism (SSCP) analysis of the coding regions of these genes in idiopathic sleep disorder patients diagnosed with excessive daytime sleepiness (EDS) (n = 28), narcolepsy (n = 28), Tourette's syndrome/chronic vocal or motor tic disorder (n = 70), and control subjects (n = 110). Two EDS patients showed a Pro11Thr change. One Tourette's syndrome patient was found to have a Pro10Ser alteration. The Pro10Ser and Pro11Thr variants were not found in non-disease populations. Analysis of the ability of the mutant receptors to mobilize calcium compared to the wild-type receptor in response to orexin agonists indicated that they resulted in decreased potency at high (etaM) concentrations of orexin ligands. Further work is warranted to study the variability of the orexin/hypocretin system in a variety of disorders characterized by EDS.

Amino Acid Sequence↗

PubMed2004

Evaluation of dynamic studies of MR mammography for the diagnosis of intraductal lesions with nipple discharge.

OBJECTIVES: We assessed the utility of dynamic magnetic resonance imaging (MRI) in differentiating benign from malignant lesions of the breast and then applied MRI to diagnose intraductal breast tumors with nipple discharge. METHODS: Gadolinium (Gd)-enhanced MR mammography was performed on 74 patients with breast tumors and 8 patients with nipple discharge. RESULTS: The steepest slopes of the contrast medium uptake (S slope) s from time-intensity curves were significantly different between malignant and benign lesions. At S slope threshold of 0.95% /second, malignancy was predicted with a sensitivity and specificity of 75% . Six of 8 cases with nipple discharge were successfully identified by MR ductography by injecting Gd-DTPA into discharging ducts. Among them, 2 non-invasive ductal carcinomas were differentiated from benign lesions by the S slope value. CONCLUSIONS: Dynamic MR mammography is an useful modality for differentiating breast lesions and has potential for evaluating intraductal lesions with nipple discharge.

Adult↗

PubMed2003

Measurement of the two-photon correlation of synchrotron radiation in the VUV region by a delay-time modulation technique.

The two-photon correlation (second-order coherence) of synchrotron radiation in the VUV region (hnu = 55 eV) has been measured using a novel photon-counting method. A new technique has been developed to measure a small bunching effect by using a coincidence unit composed of a constant fraction discriminator, a time-to-amplitude converter (TAC), a single-channel analyzer (SCA) and two solid-state switches. The path of the circuit through which the stop signal for the TAC passes can be changed by a control voltage generated by a function generator, and the relative arrival time of two photons on condition that the output signal from the SCA appears is consequently changed. By modulating the arrival time and measuring the output rate from the SCA with a digital lock-in amplifier, an apparent bunching effect has been observed which is characteristic of the chaotic light. The electron-beam emittance in the horizontal direction was estimated as 39(-8)(+13) nm rad by this experiment, and the value was consistent with the designed value of 36 nm rad.

Journal Article↗

PubMed2003

Characterization of a family of endogenous neuropeptide ligands for the G protein-coupled receptors GPR7 and GPR8.

GPR7 and GPR8 are orphan G protein-coupled receptors that are highly similar to each other. These receptors are expressed predominantly in brain, suggesting roles in central nervous system function. We have purified an endogenous peptide ligand for GPR7 from bovine hypothalamus extracts. This peptide, termed neuropeptide B (NPB), has a C-6-brominated tryptophan residue at the N terminus. It binds and activates human GPR7 or GPR8 with median effective concentrations (EC(50)) of 0.23 nM and 15.8 nM, respectively. In situ hybridization shows distinct localizations of the prepro-NPB mRNA in mouse brain, i.e., in paraventricular hypothalamic nucleus, hippocampus, and several nuclei in midbrain and brainstem. Intracerebroventricular (i.c.v.) injection of NPB in mice induces hyperphagia during the first 2 h, followed by hypophagia. Intracerebroventricular injection of NPB produces analgesia to s.c. formalin injection in rats. Through EST database searches, we identified a putative paralogous peptide. This peptide, termed neuropeptide W (NPW), also has an N-terminal tryptophan residue. Synthetic human NPW binds and activates human GPR7 or GPR8 with EC(50) values of 0.56 nM and 0.51 nM, respectively. The expression of NPW mRNA in mouse brain is confined to specific nuclei in midbrain and brainstem. These findings suggest diverse physiological functions of NPB and NPW in the central nervous system, acting as endogenous ligands on GPR7 andor GPR8.

Amino Acid Sequence↗

PubMed2003

Computed tomography-guided transarterial chemoembolization as the initial therapy for hepatocellular carcinoma: experience of 75 cases in a single institute.

We present the survival rates of 75 nonruptured hepatocellular carcinoma cases initially treated with computed tomography-guided transarterial chemoembolization in a single institute. The 1-, 3-, and 5-year survival rates were 93.9%, 74.7%, and 47.4% in 50 Child's A cases; 75.0%, 43.6%, and 6.8% in 20 Child's B cases; and 60.0%, 40.0%, 0.0% in 5 Child's C cases, respectively. The 1-, 3-, and 5-year survival rates of the 38 estimated resectable hepatocellular carcinoma cases (Child's A, tumors limited in a single lobe) were 94.7%, 82.0%, and 44.6%, respectively. The 1-, 3-, and 5-year survival rates of the 41 cases with estimated indication for percutaneous ethanol injection therapy (tumors less than 3 cm in diameter and three or fewer in number) were 96.8%, 84.6%, and 55.5% in 31 Child's A cases; and 90.0%, 46.7%, and 0% in 10 Child's B cases, respectively. In conclusion, computed tomography-guided transarterial chemoembolization is an excellent primary therapy for hepatocellular carcinoma.

Adult↗

PubMed2002

GEX1 compounds, novel antitumor antibiotics related to herboxidiene, produced by Streptomyces sp. I. Taxonomy, production, isolation, physicochemical properties and biological activities.

Six structurally related antitumor antibiotics named GEX1 compounds were isolated from a culture broth of Streptomyces sp. GEX1A was identified as a known herbicide, herboxidiene, structurally interested by the tetrahydropyran moiety and the side chain including a conjugated diene. GEX1Q1 to approximately Q5 were determined as novel compounds related to herboxidiene. All GEX1 compounds showed cytotoxicity with IC50 values of 0.0037 to approximately 0.99 microM against human tumor cell lines in vitro, but were not active against both gram-positive and -negative bacteria. Though GEX1A/herboxidiene exhibited antitumor activity in murine tumor-planted mouse models, both GEX1Q3 and GEX1Q5 did not.

Animals↗

PubMed2002

GEX1 compounds, novel antitumor antibiotics related to herboxidiene, produced by Streptomyces sp. II. The effects on cell cycle progression and gene expression.

Six GEX1 compounds, GEX1A/herboxidiene and its related 5 novel compounds, were isolated from a culture broth of Streptomyces sp. GEX1 compounds induced both G1 and G2/M arrest in a human normal fibroblast cell line, WI-38. All six compounds up-regulated luciferase reporter gene expression directed by enhancer/promoter of various genes, such as cdc2, IL-2 and SV40 early genes. All GEX1 compounds showed cytotoxic activities in the same order of the up-regulating activities on gene expression, suggesting that these two activities are related. Despite the up-regulating activities on the reporter gene expression, GEX1A/herboxidiene did not enhance the expression of any endogenous genes involved in the cell cycle, proliferation and apoptosis. Although the unique effects of GEX1 compounds on cell cycle and the reporter gene expression were similar to those of trichostatin A (TSA), an inhibitor of histone deacetylase (HDAC), GEX1A/herboxidiene did not affect histone acetylation in cells. In addition, GEX1A/herboxidiene treatment gave rise to the shorter sized transcripts of the cdc25A and cdc2 genes as well as the normal sized ones. These results suggest that GEX1 compounds modulate gene expression by an unknown mechanism.

Antibiotics, Antineoplastic↗