Biomedical subjects

Yuichi Ito

Publications and source records attributed to Yuichi Ito.

9 recordsLinked to original sources

PubMed2006

In vitro chemosensitivity test to predict chemosensitivity for paclitaxel, using human gastric carcinoma tissues.

BACKGROUND: Therapy guided by chemotherapy sensitivity and resistance assays may lead to rational treatment decisions. Paclitaxel, one of several new drugs for gastric carcinoma, has not been extensively evaluated by in vitro chemosensitivity tests. METHODS: Chemosensitivity testing by histoculture drug response assay (HDRA) was performed with fresh specimens of primary tumor from 113 patients with gastric carcinoma. The test was performed in medium containing paclitaxel at three different concentrations for the initial 45 samples. Correlations between the results of chemosensitivity testing, determined at the optimal concentration, and the patients' clinicopathologic factors and outcome were then assessed for all patients. RESULTS: By analyzing the initial 45 samples, 10 microg/ml was considered the optimal concentration of paclitaxel for this test. HDRA was successfully performed for 100 of 113 samples and chemosensitivity, calculated as the percentage of optical density of a tumor treated with anticancer drugs in relation to the optical density of the tumor cultured in the medium only, was distributed widely at this concentration. No significant correlation was observed between chemosensitivity and age, sex, clinical stage, histopathologic type, and outcome of patients with gastric carcinoma. CONCLUSION: A histoculture drug response assay can now be performed to predict the chemosensitivity of paclitaxel at the concentration found in the current study. The accuracy of the assay to actually predict survival needs to be validated by a prospective clinical trial involving patients who have received paclitaxel in the postoperative adjuvant setting.

Adult↗

PubMed2006

Prediction of preservative sensitization potential using surface marker CD86 and/or CD54 expression on human cell line, THP-1.

Preservatives are important components in many products, but have a history of purported allergy. Several assays [e.g., guinea pig maximization test (GPMT), local lymph node assay (LLNA)] are used to evaluate allergy potential of preservatives. We recently developed the human Cell Line Activation Test (h-CLAT), an in vitro skin sensitization test using human THP-1 cells. This test evaluates the augmentation of CD86 and CD54 expression, which are key events in the sensitization process, as an indicator of allergy following treatment with test chemical. Earlier, we found that a sub-toxic concentration was needed for the up-regulation of surface marker expression. In this study, we further evaluate the capability of h-CLAT to predict allergy potential using eight preservatives. Cytotoxicity was determined using propidium iodide with flow cytometry analysis and five doses that produce a 95, 85, 75, 65, and 50% cell viability were selected. If a material did not have any cytotoxicity at the highest technical dose (HTD), five doses are set using serial 1.3 dilutions of the HTD. The test materials used were six known allergic preservatives (e.g., methylchloroisothiazolinone/methylisothiazolinone, formaldehyde), and two non-allergic preservatives (methylparaben and 4-hydroxybenzoic acid). All allergic preservatives augmented CD86 and/or CD54 expression, indicating h-CLAT correctly identified the allergens. No augmentation was observed with the non-allergic preservatives; also correctly identified by h-CLAT. In addition, we report two threshold concentrations that may be used to categorize skin sensitization potency like the LLNA estimated concentration that yield a three-fold stimulation (EC3) value. These corresponding values are the estimated concentration which gives a relative fluorescence intensity (RFI) = 150 for CD86 and an RFI = 200 for CD54. These data suggest that h-CLAT, using THP-1 cells, may be able to predict the allergy potential of preservatives and possibility classify the potency of an allergen.

Allergens↗

PubMed2006

Phenotypic alterations and cytokine production in THP-1 cells in response to allergens.

In the induction phase of allergic contact hypersensitivity, dendritic cells (DCs), including Langerhans cells (LCs) present in epidermis, can trigger an efficient T cell response once they have matured in response to an allergen. Upon maturation, DCs have been shown to induce expression of several surface molecules and the up-regulation of cytokine production. We have previously shown that THP-1 cells, human acute monocytic leukemia cell line, can discriminate between allergens and irritants by measuring expression of surface markers, CD86 and CD54, following chemical exposure. At the same time, we have also reported that augmented expression of HLA and CD80, and production of IL-1beta were up-regulated in THP-1 cells when treated with an allergen, 2,4-dinitrochlorobenzene (DNCB). In the present study, we first evaluated whether THP-1 cells induced the phenotypic changes and the production of cytokines, which are observed in the process of DC maturation, when treated with two known allergens, DNCB and nickel sulfate (NiSO(4)), and one irritant (sodium lauryl sulfate (SLS)). Exposure to DNCB and NiSO(4) induced significant augmentation of CD40 and CD83 expression as well as CD86 and CD54. Also, TNF-alpha and IL-8 secretion were markedly induced by DNCB and NiSO(4) in a dose-dependent manner. In addition, DNCB and NiSO(4) augmented CD1a expression and production of IL-6, respectively. On the contrary, SLS did not change any of these markers. We then evaluated a series of chemicals, including six known allergens (e.g., hydroquinone (HQ)) and two non-allergens (e.g., methyl paraben (MP)), in order to investigate the potential increase of CD86, CD54, CD40, and CD83 expression on THP-1 cells, and production of TNF-alpha and IL-8. Indeed, all tested allergens, except eugenol (EU), caused significant increased changes in at least four of the analyzed six markers, while non-allergens did not induce any changes. EU significantly augmented CD86, CD54 and CD40 expression. These results revealed that the wide variety of responses to allergens in THP-1 cells may emulate allergen-induced maturation processes of DCs. It is suggested that THP-1 cells, which could develop several DC-like properties, are suitable for identifying sensitizing potential of chemicals.

Allergens↗

PubMed2006

Biological significance of isolated tumor cells and micrometastasis in lymph nodes evaluated using a green fluorescent protein-tagged human gastric cancer cell line.

PURPOSE: The biological significance of isolated tumor cells and micrometastasis in lymph node defined by the International Union against Cancer remains essentially unknown because of the lack of appropriate animal models. In the present study, we developed a lymph node micrometastasis model featuring a human gastric cancer cell line tagged with green fluorescent protein gene (GCIY-EGFP), which allows visualization of even isolated tumor cells in the development of metastasis without histologic procedure. Using this model, we investigated the effect of surgery and chemotherapy on the growth of early-phase metastasis formation in the lymph nodes. EXPERIMENTAL DESIGN: The time course of spontaneous inguinal lymph node metastasis after s.c. inoculation of GCIY-EGFP cells into nude mice was examined with fluorescence dissecting microscopy. Then, the effects of surgical removal of the primary tumor with or without anti-asialo GM1 treatment or postoperative chemotherapy on the growth of isolated tumor cells and micrometastasis in the lymph nodes were examined. RESULTS: GCIY-EGFP cells were found to metastasize spontaneously to the inguinal lymph nodes to form isolated tumor cells, micrometastasis, and, finally, develop macroscopic metastasis at 1 to 2, 3 to 5, and 5 weeks postinjection, respectively. When the primary tumors were removed within 2 weeks of inoculation, isolated tumor cells, but not micrometastasis, in the lymph nodes regressed by 4 weeks after surgery in all the mice examined (five of five). This spontaneous regression of isolated tumor cells was completely reversed by anti-asialo GM1 treatment, which could deplete natural killer cells effectively in nude mice. Chemotherapy following resection of the primary tumor at an early stage partially eliminated the remaining micrometastasis in the lymph nodes. CONCLUSIONS: These results suggest that isolated tumor cells in the regional lymph nodes regressed by removal of the primary tumor mainly via natural killer cell-mediated antitumor activity and that micrometastasis in the lymph nodes could be effectively eliminated by the postoperative chemotherapy.

Animals↗

PubMed2006

A case of TURBT after penile prosthesis implantation.

The patient was a 66-year-old man who had undergone implantation of a penile prosthesis for organic erectile dysfunction 7 years prior to consulting our hospital with a complaint of gross hematuria. Since a pedunculated, superficial tumor 1 cm in diameter was noted lateral to the left ureteral orifice, transurethral resection of the bladder tumor (TURBT) was performed. In this patient, we were able to insert the sheath with no difficulty, and the surgical procedure was done smoothly, resulting in complete resection of the tumor. However, the location of the tumor in the anterior or posterior wall of the bladder predicted difficulty of the tumor resection. Therefore, we consider it important to sufficiently evaluate the feasibility of complete TURBT before surgery and to thoroughly examine the patient for benign prostatic hyperplasia and bladder cancer, which can cause difficulty with post-implantation ransurethral procedures, and to perform transurethral surgery before implantation, if prosthesis implantation is planned.

Aged↗

PubMed2005

Rice Annotation Database (RAD): a contig-oriented database for map-based rice genomics.

A contig-oriented database for annotation of the rice genome has been constructed to facilitate map-based rice genomics. The Rice Annotation Database has the following functional features: (i) extensive effort of manual annotations of P1-derived artificial chromosome/bacterial artificial chromosome clones can be merged at chromosome and contig-level; (ii) concise visualization of the annotation information such as the predicted genes, results of various prediction programs (RiceHMM, Genscan, Genscan+, Fgenesh, GeneMark, etc.), homology to expressed sequence tag, full-length cDNA and protein; (iii) user-friendly clone / gene query system; (iv) download functions for nucleotide, amino acid and coding sequences; (v) analysis of various features of the genome (GC-content, average value, etc.); and (vi) genome-wide homology search (BLAST) of contig- and chromosome-level genome sequence to allow comparative analysis with the genome sequence of other organisms. As of October 2004, the database contains a total of 215 Mb sequence with relevant annotation results including 30 000 manually curated genes. The database can provide the latest information on manual annotation as well as a comprehensive structural analysis of various features of the rice genome. The database can be accessed at http://rad.dna.affrc.go.jp/.

Chromosomes, Plant↗

PubMed2002

The genome sequence and structure of rice chromosome 1.

The rice species Oryza sativa is considered to be a model plant because of its small genome size, extensive genetic map, relative ease of transformation and synteny with other cereal crops. Here we report the essentially complete sequence of chromosome 1, the longest chromosome in the rice genome. We summarize characteristics of the chromosome structure and the biological insight gained from the sequence. The analysis of 43.3 megabases (Mb) of non-overlapping sequence reveals 6,756 protein coding genes, of which 3,161 show homology to proteins of Arabidopsis thaliana, another model plant. About 30% (2,073) of the genes have been functionally categorized. Rice chromosome 1 is (G + C)-rich, especially in its coding regions, and is characterized by several gene families that are dispersed or arranged in tandem repeats. Comparison with a draft sequence indicates the importance of a high-quality finished sequence.

Arabidopsis↗

PubMed2002

Frictional torque and wear of retrieved hip prostheses: a comparison between alumina/PE and Co-Cr/PE prostheses.

Frictional torque and wear were measured in 67 retrieved cups with internal diameters of 32 mm. Thirty cups were combined with alumina heads and 37 were combined with metal heads. A lower prevalence of cup loosening was observed in alumina-polyethylene implants than in metal-polyethylene implants. No relation between frictional torque and stability of implants was detected for either type, whereas retrieved cups of alumina-polyethylene implants showed lower frictional torque than those of metal-polyethylene implants. Less wear was observed in the cups of alumina-polyethylene implants (0.13 mm/y) than in those of metal-polyethylene implants (0.19 mm/y). Less wear was observed in cups without loosening than in those with loosening in both types. These results suggest that wear has a greater influence on the stability of cups than frictional torque.

Adult↗

PubMedDate not supplied

Combination of oral fluoropyrimidine and docetaxel: reappraisal of synergistic effect against gastric carcinoma xenografts.

BACKGROUND: The synergistic antitumor effect of a combination of docetaxel and capecitabine is reported to be attributable to docetaxel-mediated up-regulation of thymidine phosphorylase (dThdPase). MATERIALS AND METHODS: Intravenous docetaxel (15 mg/kg) was given to nude mice bearing xenografts of the gastric cancer cell lines MKN45 and MKN28. Mice were sacrificed on days 7, 10 and 22 and tumor samples were taken to measure the activities of thymidylate synthase, dihydropyrimidine dehydrogenase, dThdPase and orotate phosphoribosyltransferase. The efficacy of capecitabine or S-1, alone and in combination with docetaxel, was then evaluated in vivo. Docetaxel was administered intravenously on days 8 and 22 at 15 mg/kg, while capecitabine (269 mg/kg) or S-1 (7.5 mg/kg) were administered orally 5 times a week for 4 weeks. RESULTS: Tumor regression was observed only for a combination of capecitabine and docetaxel against MKN28, while additive growth inhibition was obtained by the combination of docetaxel and both S-1 and capecitabine on MKN45 tumor xenografts. Induction of dThdPase activity was observed only for MKN45. The activity of no other enzyme was significantly affected following administration of docetaxel. CONCLUSION: The combination of oral fluoropyrimidine and docetaxel showed augmented antitumor activity, but this may be attributed to mechanisms other than changes in 5-fluorouracil-metabolizing enzymes.

Administration, Oral↗