17 research outputs found

    Bioinertization of NanoLC/MS/MS Systems by Depleting Metal Ions From the Mobile Phases for Phosphoproteomics

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    We have successfully developed a bioinertized nanoflow liquid chromatography/tandem mass spectrometry (nanoLC/MS/MS) system for the highly sensitive analysis of phosphopeptides by depleting metal ions from the mobile phase. We found that not only direct contact of phosphopeptides with metal components, but also indirect contact with nanoLC pumps through the mobile phase causes significant losses during the recovery of phosphopeptides. Moreover, electrospray ionization was adversely affected by the mobile phase containing multiple metal ions as well as by the sample solvents contaminated with metal ions used in immobilized metal ion affinity chromatography for phosphopeptide enrichment. To solve these problems, metal ions were depleted by inserting an on-line metal ion removal device containing metal-chelating membranes between the gradient mixer and the autosampler. As a result, the peak areas of the identified phosphopeptides increased an average of 9.9-fold overall and 77-fold for multiply phosphorylated peptides with the insertion of the on-line metal ion removal system. This strategy would be applicable to highly sensitive analysis of other phosphorylated biomolecules by microscale-LC/MS/MS

    Gastrointestinal Endoscopy-Assisted Minimally Invasive Surgery for Superficial Cancer of the Uvula

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    Previous studies reported that endoscopic resection is effective for the treatment of superficial pharyngeal cancers, as for digestive tract cancers. However, the optimal treatment for superficial cancer of the uvula has not been established because of the rarity of this condition. We present two male patients in their 70s with superficial cancer of the uvula, detected with upper gastrointestinal endoscopy. Both patients underwent surgical resection of the uvula under general anesthesia. The extent of the lesions was determined by means of gastrointestinal endoscopy by using magnifying observation with narrow-band imaging, enabling the performance of minimally invasive surgery. Endoscopic submucosal dissection was performed to achieve en bloc resection of the intramucosal carcinoma that had infiltrated the area adjacent to the uvula. Gastrointestinal endoscopists should carefully examine the laryngopharynx to avoid missing superficial cancers. Our minimally invasive treatment for superficial cancer of the uvula had favorable postoperative outcomes, and prevented postoperative loss of breathing, swallowing, and articulation functions

    Transcription of the Geminin gene is regulated by a negative-feedback loop

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    Geminin performs a central function in regulating cellular proliferation and differentiation in development and also in stem cells. Of interest, down-regulation of Geminin induces gene transcription regulated by E2F, indicating that Geminin is involved in regulation of E2F-mediated transcriptional activity. Because transcription of the Geminin gene is reportedly regulated via an E2F-responsive region (E2F-R) located in the first intron, we first used a reporter vector to examine the effect of Geminin on E2F-mediated transcriptional regulation. We found that Geminin transfection suppressed E2F1- and E2F2-mediated transcriptional activation and also mildly suppressed such activity in synergy with E2F5, 6, and 7, suggesting that Geminin constitutes a negative-feedback loop for the Geminin promoter. Of interest, Geminin also suppressed nuclease accessibility, acetylation of histone H3, and trimethylation of histone H3 at lysine 4, which were induced by E2F1 overexpression, and enhanced tri­methylation of histone H3 at lysine 27 and monoubiquitination of histone H2A at lysine 119 in E2F-R. However, Geminin5EQ, which does not interact with Brahma or Brg1, did not suppress accessibility to nuclease digestion or transcription but had an overall dominant-negative effect. These findings suggest that E2F-mediated activation of Geminin transcription is negatively regulated by Geminin through the inhibition of chromatin remodeling
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