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Biomedical subjects

S Takano

Publications and source records attributed to S Takano.

At least 55 records · Page 3Linked to original sources
PubMed2000

Synthesis and antiinflammatory activity of 7-methanesulfonylamino-6-phenoxychromones. Antiarthritic effect of the 3-formylamino compound (T-614) in chronic inflammatory disease models.

A group of derivatives of 7-methanesulfonylamino-6-phenoxychromone (1) at the pyrone and phenoxy rings was synthesized starting with 4-chloro-3-nitroanisole and evaluated against acute and chronic inflammations in oral administration in animals. Significant potency in the rat models of carrageenin-induced edema (CPE) and adjuvant-induced arthritis (AA) was realized with 2'-fluoro and 2',4'-difluoro derivatives (9a and 9d), and 3-formylamino derivative (19a) and its 2'-fluoro and 2',4'-difluoro compounds (22a and 22d), displaying AA therapeutic effect of ED40 = 2.5-7.1 mg/kg/d for 7 d and AA prophylactic effect of 53-70% inhibition at the dosage of 3 mg/kg/d for 22 d. To identify a candidate for further pharmacological study, the five compounds were subjected to evaluation of their gastro-ulcerogenic liability, leading to selection of the fluorine-free compound 19a which did not cause acute ulceration at 300 mg/kg in oral administration in rats. Compound 19a (ED40 = 3.6 mg/kg in established AA) possessed good therapeutic efficacy against type II collagen-induced arthritis in DBA/1J mice with doses of 30 and 100 mg/kg, suggesting the development of 19a (designated T-614) as a prospective disease-modifying antirheumatic agent. In addition, a preparative-scale synthetic route to T-614 has been established.

Animals↗
PubMed2000

PF1163A and B, new antifungal antibiotics produced by Penicillium sp. II. Physico-chemical properties and structure elucidation.

The structures of new antifungal antibiotics, PF1163A and B, were elucidated by spectroscopic analyses of the degradation products and by X-ray crystallography of the de-2-hydroxyethyl derivative of PF1163B. Both antibiotics consist of a 13-membered macrocyclic structure containing a derivative of N-methyl tyrosine and a hydroxy fatty acid. PF1163A differs from PF 1163B by having an additional hydroxyl group on the side chain.

Antifungal Agents↗
PubMed2000

Complementation of an hMSH2 defect in human colorectal carcinoma cells by human chromosome 2 transfer.

The human colorectal tumor cell line LoVo has a homozygous deletion in the hMSH2 gene from exon 3 to exon 8, is deficient in mismatch repair (MMR) activity, and exhibits microsatellite instability. To determine whether the introduction of a wild type hMSH2 into LoVo restores MMR activity and stabilizes microsatellite loci, we transferred a chromosome 2 fragment containing hMSH2 into a homologous recombination-proficient chicken DT40/human hybrid (DT40 2C) and a human chromosome 2 in a mouse A9 hybrid to LoVo. Transfers of these chromosomes into LoVo resulted in LoVo both with and without a wild-type hMSH2. Complete correlation was found between the presence of the wild-type hMSH2 and hMSH2 expression, an increased stability in microsatellite loci, and competency in MMR. The hMSH2-positive LoVo hybrids also showed an increased sensitivity to N-methyl-N'-nitro-N-nitrosoguanidine. This enhanced toxicity is associated with G(2) cell-cycle arrest followed by premature mitosis and cell death. These results suggest that hMSH2 may be responsible for complementing mutator and drug-resistant phenotypes in chromosome 2-transferred LoVo cells. To test whether the hMSH2 in DT40 2C cells can be modified by homologous recombination, we transfected DT40 2C with a targeting vector containing an hMSH2 exon 4 disrupted by the zeocin-resistant gene. The results showed that the hMSH2 locus in DT40 2C was efficiently targeted by an exogeneously transfected homologous sequence, suggesting that transfer of a modified hMSH2 from DT40 2C to LoVo via chromosome transfer could be used to determine the function of hMSH2.

Animals↗
PubMed2000

[Ganglioglioma].

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Adolescent↗
PubMed1999

Induction of apoptosis in macrophages by cationic liposomes.

The effects of liposomes on apoptosis in macrophages were evaluated from DNA content and DNA fragmentation. Cationic liposomes composed of different kinds of cationic lipids induced apoptosis in mouse splenic macrophages and the macrophage-like cell line, RAW264.7 cells. Generation of reactive oxygen radicals from macrophages treated with cationic liposomes was detected using flow cytometry, and further apoptosis was inhibited by the addition of oxidant scavenger, N-acetylcysteine. From these findings, the production of reactive oxygen species may be important in the regulation of apoptosis induced by cationic liposomes.

Acetylcysteine↗
PubMed1999

CRTH2, an orphan receptor of T-helper-2-cells, is expressed on basophils and eosinophils and responds to mast cell-derived factor(s).

We have recently cloned a putative chemoattractant receptor, named CRTH2, which is preferentially expressed on human T-helper- (Th) 2 but not Th1 cells. In this study, we demonstrated that CRTH2 is also highly expressed on peripheral blood basophils and eosinophils. Our search for a CRTH2 ligand identified mast cells as the possible producers of a ligand. When stimulated with an anti-FcepsilonR1 antibody, cord blood-derived mast cells secreted factor(s) that induced Ca(2+) mobilization in CRTH2-expressing K562 cells but not in mock transfected cells. These findings implied the involvement of CRTH2 in mast cell-mediated immune responses such as allergic reactions.

Basophils↗
PubMed1999

No requirement of P2X1 purinoceptors for platelet aggregation.

ADP produces a series of responses in rabbit platelets such as shape changes, aggregation and intracellular Ca2+ mobilization. In human platelets, the P2X1 receptor mediates a rapid increase in intracellular Ca2+ concentration ([Ca2+]i) upon stimulation with ADP. We investigated whether this phenomenon is also present in rabbit platelets. We found that the P2X1 receptor-mediated response was absent because there was (1) no elevation of [Ca2+]i in response to alpha,beta-methylene-ATP, a selective P2X1 receptor agonist, in fura-2-loaded platelets; (2) no change in the ADP-induced [Ca2+]i increase and platelet aggregation after P2X1 receptor desensitization with alpha,beta-methylene-ATP; (3) complete inhibition of the ADP-induced [Ca2+]i elevation by the P2Y1 receptor specific antagonist, A3'P5'PS, with a similar ID50 value both in the presence and absence of external Ca2+. These results indicate that ADP-induced [Ca2+]i elevation is mainly mediated by P2Y1 receptors in rabbit platelets. We conclude that the P2X1 receptor does not play a significant role in the ADP-induced platelet shape changes and aggregation.

Adenosine Diphosphate↗
PubMed1999

Selective expression of a novel surface molecule by human Th2 cells in vivo.

The search for reliable marker molecules discriminating between human Th1 and Th2 cells identified a gene encoding a novel member of the G protein-coupled leukocyte chemoattractant receptor family, which is selectively expressed in Th2 but not Th1 lineage cells, thereby named CRTH2 (chemoattractant receptor-homologous molecule expressed on Th2 cells). Studies with anti-CRTH2 mAbs demonstrated that CRTH2 was expressed in a small population (0.4-6.5%) of CD4+ T cells in fresh PBMCs of healthy adults, but no remarkable expression was seen in B cells and NK cells. In some cases, CD8+ T cells ( approximately 3.5%) expressed CRTH2. Phenotypes of CD4+ T cells expressing CRTH2 were CD45RA-, CD45RO+, and CD25+, similar to those of Ag-activated effector/memory T cells. Freshly isolated CRTH2+ CD4+ T cells produced Th2- but little or no Th1-type cytokines upon stimulation with PMA and ionomycin. In addition, an allergen-induced proliferative response in fresh PBMCs was significantly and selectively reduced by subtracting CRTH2+ cells. Together, these results indicate that CRTH2 is selectively expressed in vivo in an activated state of Th2 cells including allergen-responsive Th2 cells, suggesting its pivotal roles in ongoing Th2-type immune reactions.

Adult↗
PubMed1999

Prospective study of interferon therapy for compensated cirrhotic patients with chronic hepatitis C by monitoring serum hepatitis C RNA.

Because interferon therapy exhibits low efficacy for cirrhotic patients infected with hepatitis C virus, this prospective study was conducted to determine effective interferon regimens tailored to treatment response by monitoring HCV RNA status. A total of 157 cirrhotic patients were enrolled to receive 9 million units (MU) of interferon three times a week. The HCV RNA values were drawn 8 weeks apart and the patients were randomized to a further 16 or 32 weeks of treatment after two sequential findings of negativity for HCV RNA. A total of 73 out of 157 patients (46%) proceeded to randomization to different durations of treatment, 37 short-course and 36 long-course (duration: 38 +/- 8 and 49 +/- 13 weeks; total amount of interferon: 940 +/- 240 and 1130 +/- 390 MU, respectively). The remaining 84 patients without two sequential negative serum HCV RNA determinations received 44.8 +/- 27.4 weeks of interferon (IFN) therapy with total amount of 993 +/- 633 MU. Of these 157 patients, sustained virological and biochemical response was shown in 32 (20%) and 37 patients (24%), respectively. Sustained virological and biochemical response rate in the randomized patients was significantly higher than in nonrandomized patients (41% vs. 2%, and 38% vs. 11%; each P <.01). Of the 73 randomized patients, the rate of sustained virological response in patients with long-course treatment (50%) was significantly higher than that of patients with short-course treatment (32%) (P =.026: log-rank test), and in patients with early disappearance of HCV RNA especially within 8 weeks, in patients with low virus load (</=10(6.3) copies/mL) and with HCV 2a. Multivariate analysis revealed that HCV RNA level and subtypes were the most important factors contributing to sustained virological response. Interferon is effective even in cirrhotic patients with low viral load and HCV 2a, but requires a longer course of administration.

Adult↗
PubMed1999

Novel polymorphism of the 5-lipoxygenase activating protein (FLAP) promoter gene associated with asthma.

The human 5-lipoxygenase activating protein (FLAP) gene is one of the key genes involved in the production of the cysteinyl-leukotrienes. We studied novel polymorphism of the FLAP promoter gene and attempted to clarify the relationship between this polymorphism and asthma. We sequenced the FLAP promoter region, containing the -170 to +46-bp sequence from the translational start codon, and found two homozygotes of novel alleles in the polyadenyl region which showed 21 A repeats and 18 A repeats, respectively. The frequency of the 21 A repeats was 52/71 (73.2%) in asthmatics and 39/71 (54.9%) in control subjects. The difference between these frequencies was statistically significant (P = 0.035). This is the first report of FLAP promoter gene polymorphism associated with asthma. Our data suggest that FLAP promoter gene polymorphism might play a crucial role in the pathogenesis of asthma.

5-Lipoxygenase-Activating Proteins↗
PubMed1999

Elevated adrenomedullin in the vitreous of patients with proliferative vitreoretinopathy.

PURPOSE: To explore the possible involvement of adrenomedullin in the pathophysiology of proliferative vitreoretinopathy. METHODS: The radioimmunoassay technique was used to determine immunoreactive adrenomedullin concentrations in the vitreous fluid from 41 eyes of 41 patients undergoing vitrectomy for a variety of retinal conditions, including proliferative vitreoretinopathy, proliferative diabetic retinopathy, age-related macular degeneration, and macular hole. RESULTS: Immunoreactive adrenomedullin levels in the vitreous of patients with proliferative vitreoretinopathy were significantly higher than those of patients with proliferative diabetic retinopathy (P < .005), age-related macular degeneration (P < .001), and macular hole (P < .0001). CONCLUSION: Adrenomedullin may be involved in the pathophysiology of proliferative vitreoretinopathy.

Adrenomedullin↗
PubMed1999

NIH 3T3 cells malignantly transformed by mot-2 show inactivation and cytoplasmic sequestration of the p53 protein.

In previous studies we have reported that a high level of expression of mot-2 protein results in malignant transformation of NIH 3T3 cells as analyzed by anchorage independent growth and nude mice assays [Kaul et al., Oncogene, 17, 907-11, 1998]. Mot-2 was found to interact with tumor suppressor protein p53. The transient overexpression of mot-2 was inhibitory to transcriptional activation function of p53 [Wadhwa et al., J. Biol. Chem., 273, 29586-91, 1998]. We demonstrate here that mot-2 transfected stable clone of NIH 3T3 that showed malignant properties indeed show inactivation of p53 function as assayed by exogenous p53 dependent reporter. The expression level of p53 in response to UV-irradiation was lower in NIH 3T3/mot-2 as compared to NIH 3T3 cells and also exhibited delay in reaching peak. Furthermore, upon serum starvation p53 was seen to translocate to the nucleus in NIH 3T3, but not in its mot-2 derivative. The data suggests that mot-2 mediated cytoplasmic sequestration and inactivation of p53 may operate, at least in part, for malignant phenotype of NIH 3T3/mot-2 cells. NIH 3T3/mot-2 cells show inactivation of p53 protein.

3T3 Cells↗
PubMed1999

Radical surgery for Budd-Chiari syndrome. Direct excision and repair for obstruction of the vena cava (Budd-Chiari syndrome) under hepatic vascular exclusion using a centrifugal pump.

OBJECTIVE: To attempt to reduce the incidence of hepatic and cardiac failure after radical surgery for the Budd-Chiari syndrome. DESIGN: Retrospective case study. SETTING: University hospital, Japan SUBJECTS: Three patients with obstruction of the vena cava (Budd-Chiari syndrome) by a thick membrane, thrombus, and a long stenosis, respectively. INTERVENTION: Direct excision and repair by patch dilatation under hepatic vascular exclusion using a Biomedicus centrifugal pump. RESULTS: Hepatic vascular exclusion provides good visibility and enables accurate assessment of the obstruction, proper treatment, and relatively little blood loss. There were no complications, particularly liver failure or heart failure, and the inferior vena cava stayed patent in all cases. Liver function was improved in all three patients. CONCLUSION: This technique is safe and reliable for removal of obstruction of the inferior vena cava (Budd-Chiari syndrome).

Animals↗