179 research outputs found

    Fundamental Study on Electrical Discharge Machining

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    The generation mechanism of crater in electrical discharge machining is analyzed with a single pulse discharge device for alloy tool steel, black alumina ceramics, cermet and cemented carbide, investigating the gap voltage, the discharge current, the shape of crater, the wear of electrode and so on. The experimental analysis makes it clear that the shape of crater has a characteristic feature for the kind of workpiece. The shape of electrode, which changes with the wear by an electric spark, has a significant effect on the shape of crater. The diameter and the depth of crater have a close relation to the discharge energy for alloy tool steel, black alumina ceramics and cermet, while those for cemented carbide are related to the discharge current. The shape factor which is the ratio of the depth to the diameter of crater is different for the work material

    Gold Nanoparticles Functionalized with Peptides for Specific Affinity Aggregation Assays of Estrogen Receptors and Their Agonists

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    Nuclear receptors regulate the transcription of genes and various functions such as development, differentiation, homeostasis, and behavior by formation of complexes with ligand and co-activator. Recent findings have shown that agonists of a ligand may have a toxic effect on cellular/tissular function through improper activation of nuclear receptors. In this study, a simple assay system of hetero-complexes of three different molecules (estrogen receptor, ligand, and co-activator peptide) has been developed. This assay system employs functionalized gold nanoparticles (GNPs: 15 nm in diameter). The surfaces of the GNPs were modified by a 12- or 20-amino-acid peptide that contains the sequence of co-activator for activating nuclear receptor by an agonist ligand. Owing to the affinity of the peptide, the functionalized GNPs aggregate faster when the nuclear receptor and the agonist ligand are also present. The aggregation of GNPs can be identified by shifts in adsorption spectrum, which give information about the specificity of agonist ligands. Similarly, this spectrum shift can measure concentration of known agonist ligand. This simple agonist screening will be employed as high through-put analysis (HTA) in the discovery of drugs that act through nuclear receptors

    フローサイトメトリーによる酵母生菌数の迅速測定

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    東京水産大学食品生産学科東京水産大学食品生産学科東京水産大学食品生産学科東京水産大学食品生産学科東京水産大学食品生産学

    Prolapse of Intussusception through the Anus as a Result of Sigmoid Colon Cancer

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    Adult intussusception is rare and most often associated with cancer. We report a case of intussuscepted sigmoid colon into the rectum protruding from the anus of a 47-year-old woman. The cause of the intussusception was sigmoid colon cancer. We removed the intussuscepted part of the sigmoid colon as well as the rectum and regional lymph nodes. The patient recovered uneventfully and there has been no evidence of recurrence of the cancer

    Phase II study of S-1 on alternate days plus bevacizumab in patients aged ≥ 75 years with metastatic colorectal cancer (J-SAVER)

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    BackgroundAlternate-day administration of S-1 is thought to reduce toxicities. This phase II study evaluated S-1 on alternate days combined with bevacizumab as first-line treatment for elderly patients with metastatic colorectal cancer.Patients and methodsEligible patients had histologically proven colorectal adenocarcinoma, measurable metastatic lesions, age ≥ 75 years, Eastern Cooperative Oncology Group performance status ≤ 1, no previous chemotherapy, and refused oxaliplatin- or irinotecan-containing regimens. Patients received 40 mg, 50 mg, or 60 mg (body surface area ≤ 1.25 m2, > 1.25 to ≤ 1.50 m2, or > 1.50 m2, respectively) of S-1 twice orally on Sunday, Monday, Wednesday, and Friday every week. Bevacizumab (7.5 mg/kg) was administered every 3 weeks. The primary endpoint was progression-free survival.ResultsOf 54 enrolled patients, 50 patients were evaluated for efficacy and 53 for safety. The median age was 79 years (range 75–88 years). The median progression-free survival was 8.1 months (95% confidence interval (CI) 6.7–9.5 months). The median overall survival was 23.1 months (95% CI 17.4–28.8 months). The response rate was 44% (95% CI 30.2–57.8%), and the disease control rate was 88% (95% CI 79.0–97.0%). Grade 3 or higher hematologic, non-hematologic, and bevacizumab-related adverse events occurred in 9%, 11%, and 25% of patients, respectively. The most common grade 3 and 4 treatment-related adverse events were hypertension (11%), nausea (6%), fatigue (6%), anemia (6%), and proteinuria (6%). Only 6 patients discontinued treatment due to adverse events.ConclusionS-1 on alternate days combined with bevacizumab showed better tolerability and comparable survival compared with the results of similar studies

    Augmented antitumor activity of 5‐fluorouracil by double knockdown of MDM4 and MDM2 in colon and gastric cancer cells

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    Inactivation of the TP53 tumor suppressor gene is essential during cancer development and progression. Mutations of TP53 are often missense and occur in various human cancers. In some fraction of wild‐type (wt) TP53 tumors, p53 is inactivated by upregulated murine double minute homolog 2 (MDM2) and MDM4. We previously reported that simultaneous knockdown of MDM4 and MDM2 using synthetic DNA‐modified siRNAs revived p53 activity and synergistically inhibited in vitro cell growth in cancer cells with wt TP53 and high MDM4 expression (wtTP53/highMDM4). In the present study, MDM4/MDM2 double knockdown with the siRNAs enhanced 5‐fluorouracil (5‐FU)‐induced p53 activation, arrested the cell cycle at G1 phase, and potentiated the antitumor effect of 5‐FU in wtTP53/highMDM4 human colon (HCT116 and LoVo) and gastric (SNU‐1 and NUGC‐4) cancer cells. Exposure to 5‐FU alone induced MDM2 as well as p21 and PUMA by p53 activation. As p53‐MDM2 forms a negative feedback loop, enhancement of the antitumor effect of 5‐FU by MDM4/MDM2 double knockdown could be attributed to blocking of the feedback mechanism in addition to direct suppression of these p53 antagonists. Intratumor injection of the MDM4/MDM2 siRNAs suppressed in vivo tumor growth and boosted the antitumor effect of 5‐FU in an athymic mouse xenograft model using HCT116 cells. These results suggest that a combination of MDM4/MDM2 knockdown and conventional cytotoxic drugs could be a promising treatment strategy for wtTP53/highMDM4 gastrointestinal cancers

    Correlations of survival with progression-free survival, response rate, and disease control rate in advanced biliary tract cancer: a meta-analysis of randomised trials of first-line chemotherapy

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    Background: The need to promote novel drug development for advanced biliary tract cancer (ABTC) has emphasised the importance of determining whether various efficacy end points can act as surrogates for overall survival (OS).Methods: We conducted a literature search of randomised trials of first-line chemotherapy for ABTC and investigated correlations between efficacy end points and OS using weighted linear regression analysis. The ratios of the median OS, median progression-free survival (PFS), response rate, and disease control rate in each trial were used to summarise treatment effects. The surrogate threshold effect (STE), which was the minimum treatment effect on PFS required to predict a non-zero treatment effect on OS, was calculated.Results: Seventeen randomised trials with 36 treatment arms were identified, and a sample size of 2148 patients with 19 paired arms was analysed. The strongest correlation between all evaluated efficacy end points was observed between median OS and median PFS ratios (r2=0.66). In trials with gemcitabine-containing therapies and targeted agents, the r2-values were 0.78. The STE was estimated at 0.83 for all trials and 0.81 for trials with gemcitabine-containing therapies, and was not calculated for trials with targeted agents.Conclusions: The median PFS ratio correlated well with the median OS ratio, and may be useful for planning a clinical trial for novel drug development

    Malignant transformation arising from mature cystic teratoma of the ovary presenting as ovarian torsion: a case report and literature review

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    Objective: Ovarian torsion is an acute gynecological condition. Torsion is more likely to occur with benign rather than malignant tumors. Mature cystic teratoma of the ovary (MCTO) is frequent in women of reproductive age; however, the incidence of malignant transformation is approximately 2%. We report a case of malignant transformation of MCTO presenting as ovarian tumor torsion. Case report: A 51-year-old premenopausal woman was diagnosed with mature cystic teratoma in the left ovary 7 years ago. The patient visited our hospital because she had been experiencing of pain in left lower abdomen for the past two days. She was diagnosed with ovarian tumor torsion and underwent emergency surgery. The left ovarian tumor was twisted, and left salpingo-oophorectomy was performed. Histopathological examination revealed squamous cell carcinoma arising from the MCTO. We carefully followed the patients without performing staging laparotomy. On postoperative day 112, multiple lymph node metastases in the pelvic and para-aortic areas were found by positron-emission tomography and computed tomography. After referral to a university hospital, total hysterectomy, right salpingo-oophorectomy, partial omentectomy, and pelvic and paraaortic lymphadenectomy were performed. Metastases of squamous cell carcinoma were confirmed in the pelvic and para-aortic lymph nodes. Six courses of adjuvant chemotherapy with paclitaxel and carboplatin were given following radical surgery to prevent the recurrence of malignant transformation of MCTO. No recurrence of the disease has been observed during 2 years of follow-up. Conclusio: When physicians diagnose large ovarian tumor torsion cases, preoperative examinations should be performed, with the possibility of malignancy in mind
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