This study was conducted to investigate the initial tissue damage, morphogenesis, and reversibility of nasal lesions induced by the inhalation of dibasic esters. Young male rats were exposed, nose-only, to an aerosol/vapor mixture of dibasic esters at a concentration of 5,900 mg/cu m for 4 hr and subsequently killed at 1, 4, 7, 14, 21, and 42 days after exposure. Nasal lesions were distributed along major inspiratory airflow routes. Widespread epithelial denudation occurred in the anterior nasal cavity, but the lesions were confined to the dorsal meatus, adjacent the nasal septum, and the lateral middle meatus in the mid-anterior nasal cavity. The lesions were markedly less severe in the posterior nasal cavity and sharply confined to the tips of dorsal ethmoturbinates and adjacent nasal septum. The damaged cuboidal/nonciliated and respiratory epithelium in the anterior nasal cavity regained a normal structure by 4 and 7 days postexposure, respectively. The regeneration of damaged olfactory epithelium was related to the severity of initial tissue damage. Slightly damaged epithelium regained a normal appearance within 1-2 weeks, but the extensively denuded epithelium of the dorsal meatus in the anterior nasal cavity failed to regain a normal structure by 6 weeks. The sustentacular cells of the olfactory epithelium appeared to be the initial site of DBE nasal injury. In the early stages of regeneration, the epithelium was repaired by proliferating stem cells derived from basal cells. Numerous mitotic figures and bromodeoxyuridine labeling were found in the regenerating basal cells, stem cells, and sustentacular cells at 4 and 7 days. As repair processes advanced, the numbers of olfactory neurons and vesicles were increased with a proportional decrease in stem cells.
Dibasic esters are a solvent mixture of dimethyl adipate, dimethyl glutarate and dimethyl succinate which causes a selective degeneration of the nasal olfactory epithelium in rats following a 90-day inhalation exposure. In short-term cultures of rat nasal explants, it has been demonstrated that dibasic esters cytotoxicity is due to a carboxylesterase-mediated activation. In the present study, the putative toxic metabolites of dibasic esters, the monomethyl esters and the dicarboxylic acids, were evaluated in the explant system at concentrations ranging from 10 to 50 mM. Mononethyl adipate, monomethyl glutarate, and monomethyl succinate induced increases in nasal explant acid phosphatase release, a biochemical index of cytotoxicity. The nasal explant-mediated metabolism of Mononethyl adipate and monomethyl glutarate to their corresponding diacids paralleled the increases in acid phosphatase release. A carboxylesterase inhibitor, bis(p-nitrophenyl)phosphate, inhibited both the cytotoxicity and the hydrolysis of and monomethyl glutarate in the nasal explant system. The metabolism and cytotoxicity of monomethyl succinate was not attenuated as effectively by bis(p-nitrophenyl)phosphate pretreatment. Adipate, glutarate, and succinate induced concentration-related increases in cytotoxicity in the nasal explant system. These dicarboxylic acids were neither metabolized nor utilized significantly by the nasal explants. Diacid-induced cytotoxicity was not attenuated by bis(p-nitrophenyl)phosphate pretreatment. This study further established the utility of the nasal explant system for evaluating cytotoxicity of organic esters in vitro. It was established that both the monomethyl ester and diacid metabolites are cytotoxic in rat nasal explants. Finally, it was concluded that although both the monomethyl esters and the diacids contribute to the cytotoxic potential of dibasic esters in vitro, it is critical to establish if one or both of these are formed in vivo in order to identify the ultimate toxic metabolite of dibasic esters.
A Direct, Versatile, and Chemoselective Synthesis of Vinylogous Bis- and Monourethanes/amides and β-Keto Esters by Aza-Knoevenagel-Type Reactions of Tertiary Amides with Enolates
作者:Pei-Qiang Huang、Wei Ou
DOI:10.1002/ejoc.201601326
日期:2017.1.18
carbanions generated from methyl ketones, malonic acid monoester, 2-phenylacetate, or (benzylsulfonyl)benzene. Moreover, when higher homologous of acetate was used, beta-keto esters were obtained directly from amides. The method has been applied to the one-step synthesis of several known key intermediates in the total synthesis of alkaloids and quinoline antibiotics. An efficient and mild intramolecular Friedel-Crafts
[EN] DERIVATIVES OF AMANITA TOXINS AND THEIR CONJUGATION TO A CELL BINDING MOLECULE<br/>[FR] DÉRIVÉS DE TOXINES D'AMANITES ET LEUR CONJUGAISON À UNE MOLÉCULE DE LIAISON CELLULAIRE
申请人:HANGZHOU DAC BIOTECH CO LTD
公开号:WO2017046658A1
公开(公告)日:2017-03-23
Derivatives of Amernita toxins of Formula (I), wherein, formula (a) R 1, R 2, R 3, R 4, R 5, R 6, R 7, R 8, R 9, R 10, X, L, m, n and Q are defined herein. The preparation of the derivatives. The therapeutic use of the derivatives in the targeted treatment of cancers, autoimmune disorders, and infectious diseases.
[EN] A CONJUGATE OF A CYTOTOXIC AGENT TO A CELL BINDING MOLECULE WITH BRANCHED LINKERS<br/>[FR] CONJUGUÉ D'UN AGENT CYTOTOXIQUE À UNE MOLÉCULE DE LIAISON CELLULAIRE AVEC DES LIEURS RAMIFIÉS
申请人:HANGZHOU DAC BIOTECH CO LTD
公开号:WO2020257998A1
公开(公告)日:2020-12-30
Provided is a conjugation of cytotoxic drug to a cell-binding molecule with a side-chain linker. It provides side-chain linkage methods of making a conjugate of a cytotoxic molecule to a cell-binding ligand, as well as methods of using the conjugate in targeted treatment of cancer, infection and immunological disorders.
[EN] SUBSTITUTED BRIDGED UREA ANALOGS AS SIRTUIN MODULATORS<br/>[FR] ANALOGUES D'URÉE PONTÉS SUBSTITUÉS EN TANT QUE MODULATEURS DE SIRTUINE
申请人:GLAXOSMITHKLINE IP NO 2 LTD
公开号:WO2016079709A1
公开(公告)日:2016-05-26
The present invention relates to novel substituted bridged urea analog compounds of Formula (I) or pharmaceutically acceptable salts thereof, corresponding pharmaceutical compositions, processes for making and use of such compounds, alone or in combination with other therapeutic agents, as Sirtuin Modulators useful for increasing lifespan of a cell, and for use in treating and/or preventing a wide variety of diseases and disorders, which include, but are not limited to, for example, diseases or disorders related to aging or stress, diabetes, obesity, neurodegenerative diseases, cardiovascular disease, blood clotting disorders, inflammation, cancer, and/or flushing as well as diseases or disorders that would benefit from increased mitochondrial activity.
[EN] PROCESS FOR PREPARING BENZOTHIOPHEN-2YL BORONATE<br/>[FR] PROCÉDÉ DE PRÉPARATION DE BENZOTHIOPHÈN-2YL BORONATE
申请人:BAYER PHARMA AG
公开号:WO2019081346A1
公开(公告)日:2019-05-02
A process for preparing the benzothiophen-2-yl boronate of formula (VI) which serves as an intermediate for production of medicaments and for production of medicaments for treatment and/or prophylaxis of proliferative disorders, such as cancer and tumor diseases.