AIM： This study evaluated colorectal mucosal histamine release in response to blinded food challenge-positive and-negative food antigens as a new diagnostic procedure. METHODS： 19 patients suffering from gastrointes...AIM： This study evaluated colorectal mucosal histamine release in response to blinded food challenge-positive and-negative food antigens as a new diagnostic procedure. METHODS： 19 patients suffering from gastrointestinally mediated allergy confirmed by blinded oral provocation were investigated on grounds of their case history, skin prick tests, serum IgE detection and colorectal mucosal histamine release by ex vivo mucosa oxygenation. Intact tissue particles were incubated/stimulated in an oxygenated culture with different food antigens for 30 min. Specimens challenged with anti-human immunoglobulin E and without any stimulus served as positive and negative controls, respectively. Mucosal histamine release （% of total biopsy histamine content） was considered successful （positive）, when the rate of histamine release from biopsies in response to antigens reached more than twice that of the spontaneous release. Histamine measurement was performed by radioimmunoassay. RESULTS： The median （range） of spontaneous histamine release from colorectal mucosa was found to be 3.2 （0.1%-25.8%） of the total biopsy histamine content. Food antigens tolerated by oral provocation did not elicit mast cell degranulation 3.4 （0.4%-20.7%, P=0.4）, while anti-IgE and causative food allergens induced a significant histamine release of 5.4 （1.1%-25.6%, P = 0.04） and 8.1 （1.5%-57.9%, P = 0.008）, respectively. 12 of 19 patients （63.1%） showed positive colorectal mucosal histamine release in accordance with the blinded oral challenge responding to the same antigen （s）, while the specificity of the functional histamine release to accurately recognise tolerated foodstuffs was found to be 78.6%. In comparison with the outcome of blinded food challenge tests, sensitivity and specificity of history （30.8% and 57.1%）, skin tests （47.4% and 78.6%） or antigen-specific serum IgE determinations （57.9% and 50%） were found to be of lower diagnostic accuracy in gastrointestinally mediated allergy. CONCLUSION： Functional testing of the reactivity of colorectal mucosa upon antigenic stimulation in patients with gastrointestinally mediated allergy is of higher diagnostic efficacy.展开更多
Carbon dioxide(CO_(2)) is the main greenhouse gas and also an ideal C1 feedstock in organic synthesis because it is abundant,nontoxic,nonflammable,and renewable.The synthesis of organic carbamates using CO_(2) as a ph...Carbon dioxide(CO_(2)) is the main greenhouse gas and also an ideal C1 feedstock in organic synthesis because it is abundant,nontoxic,nonflammable,and renewable.The synthesis of organic carbamates using CO_(2) as a phosgene alternative has attracted extensive attention because of the importance of carbamates in organic synthesis and in the pharmaceutical and agrochemical industries.In recent decades,many multicomponent reaction strategies have been designed for constructing different types of organic carbamate molecules.Most of these methods rely on the in situ generation of carbamate anions from CO_(2) and amines,followed by reactions with other coupling partners.Synthetic strategies for acyclic carbamates include nucleophile‐electrophile coupling,nucleo‐phile‐nucleophile oxidative coupling,difunctionalization of unsaturated hydrocarbons,and C–H bond functionalization.Strategies for the synthesizing cyclic carbamates include carboxylative cyclization of in situ‐generated unsaturated amines and difunctionalization of unsaturated amines with CO_(2) and other electrophilic reagents.This review summarizes the recent advances in the synthesis of organic carbamates from CO_(2) using different multicomponent reaction strategies.Future perspectives and challenges in the incorporation of CO_(2) into carbamates are also presented.展开更多
A new method was developed to diastereoselectively synthesize polysubstituted 1,2‐diamine compounds from the reaction of diazoesters with arylamines and diaryl imines by using the dioxazoline ligand L2‐ligated silve...A new method was developed to diastereoselectively synthesize polysubstituted 1,2‐diamine compounds from the reaction of diazoesters with arylamines and diaryl imines by using the dioxazoline ligand L2‐ligated silver catalyst.The Lewis acidity of the silver catalyst affected the different types of substrate diastereoselectivities;It also led to the formation of amine‐exchange side products.展开更多
文摘AIM： This study evaluated colorectal mucosal histamine release in response to blinded food challenge-positive and-negative food antigens as a new diagnostic procedure. METHODS： 19 patients suffering from gastrointestinally mediated allergy confirmed by blinded oral provocation were investigated on grounds of their case history, skin prick tests, serum IgE detection and colorectal mucosal histamine release by ex vivo mucosa oxygenation. Intact tissue particles were incubated/stimulated in an oxygenated culture with different food antigens for 30 min. Specimens challenged with anti-human immunoglobulin E and without any stimulus served as positive and negative controls, respectively. Mucosal histamine release （% of total biopsy histamine content） was considered successful （positive）, when the rate of histamine release from biopsies in response to antigens reached more than twice that of the spontaneous release. Histamine measurement was performed by radioimmunoassay. RESULTS： The median （range） of spontaneous histamine release from colorectal mucosa was found to be 3.2 （0.1%-25.8%） of the total biopsy histamine content. Food antigens tolerated by oral provocation did not elicit mast cell degranulation 3.4 （0.4%-20.7%, P=0.4）, while anti-IgE and causative food allergens induced a significant histamine release of 5.4 （1.1%-25.6%, P = 0.04） and 8.1 （1.5%-57.9%, P = 0.008）, respectively. 12 of 19 patients （63.1%） showed positive colorectal mucosal histamine release in accordance with the blinded oral challenge responding to the same antigen （s）, while the specificity of the functional histamine release to accurately recognise tolerated foodstuffs was found to be 78.6%. In comparison with the outcome of blinded food challenge tests, sensitivity and specificity of history （30.8% and 57.1%）, skin tests （47.4% and 78.6%） or antigen-specific serum IgE determinations （57.9% and 50%） were found to be of lower diagnostic accuracy in gastrointestinally mediated allergy. CONCLUSION： Functional testing of the reactivity of colorectal mucosa upon antigenic stimulation in patients with gastrointestinally mediated allergy is of higher diagnostic efficacy.
文摘Carbon dioxide(CO_(2)) is the main greenhouse gas and also an ideal C1 feedstock in organic synthesis because it is abundant,nontoxic,nonflammable,and renewable.The synthesis of organic carbamates using CO_(2) as a phosgene alternative has attracted extensive attention because of the importance of carbamates in organic synthesis and in the pharmaceutical and agrochemical industries.In recent decades,many multicomponent reaction strategies have been designed for constructing different types of organic carbamate molecules.Most of these methods rely on the in situ generation of carbamate anions from CO_(2) and amines,followed by reactions with other coupling partners.Synthetic strategies for acyclic carbamates include nucleophile‐electrophile coupling,nucleo‐phile‐nucleophile oxidative coupling,difunctionalization of unsaturated hydrocarbons,and C–H bond functionalization.Strategies for the synthesizing cyclic carbamates include carboxylative cyclization of in situ‐generated unsaturated amines and difunctionalization of unsaturated amines with CO_(2) and other electrophilic reagents.This review summarizes the recent advances in the synthesis of organic carbamates from CO_(2) using different multicomponent reaction strategies.Future perspectives and challenges in the incorporation of CO_(2) into carbamates are also presented.
基金the National Natural Science Foundation of China(21472237)~~
文摘A new method was developed to diastereoselectively synthesize polysubstituted 1,2‐diamine compounds from the reaction of diazoesters with arylamines and diaryl imines by using the dioxazoline ligand L2‐ligated silver catalyst.The Lewis acidity of the silver catalyst affected the different types of substrate diastereoselectivities;It also led to the formation of amine‐exchange side products.
