Topic
Citric acid
About: Citric acid is a research topic. Over the lifetime, 17745 publications have been published within this topic receiving 277125 citations. The topic is also known as: citrate & H3cit.
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TL;DR: It is concluded that citric acid-induced bronchoconstriction is caused by tachykinin release from sensory nerves, which, in part, is mediated by endogenously released bradykinin.
Abstract: Gastroesophageal acid reflux into the airways can trigger asthma attacks. Indeed, citric acid inhalation causes bronchoconstriction in guinea pigs, but the mechanism of this effect has not been fully clarified. We investigated the role of tachykinins, bradykinin, and nitric oxide (NO) on the citric acid‐ induced bronchoconstriction in anesthetized and artificially ventilated guinea pigs. Citric acid inhalation (2‐20 breaths) caused a dose-dependent increase in total pulmonary resistance (R L ). R L value obtained after 10 breaths of citric acid inhalation was not significantly different from the value obtained after 20 breaths (p 5 0.22). The effect produced by a half-submaximum dose of citric acid (5 breaths) was halved by the bradykinin B 2 receptor antagonist HOE 140 (0.1 m mol ? kg 2 1 , intravenous) and abolished by the tachykinin NK 2 receptor antagonist SR 48968 (0.3 m mol ? kg 2 1 , intravenous). Bronchoconstriction induced by a submaximum dose of citric acid (10 breaths) was partially reduced by the administration of HOE 140, SR 48968, or the NK 1 receptor antagonist CP-99,994 (8 m mol ? kg 2 1 , intravenous) alone and completely abolished by the combination of SR 48968 and CP-99,994. Pretreatment with the NO synthase inhibitor, L -NMMA (1 mM, 10 breaths every 5 min for 30 min) increased in an L -arginine‐dependent manner the effect of citric acid inhalation on R L . HOE 140 and CP99,994 markedly reduced the L -NMMA‐potentiated bronchoconstriction to inhaled citric acid. We conclude that citric acid‐induced bronchoconstriction is caused by tachykinin release from sensory nerves, which, in part, is mediated by endogenously released bradykinin. Simultaneous release of NO by citric acid inhalation counteracts tachykinin-mediated bronchoconstriction. Our study suggests a possible implication of these mechanisms in asthma associated with gastroesophageal acid reflux and a potential therapeutic role of tachykinin and bradykinin antagonists. Ricciardolo FLM, Rado V, Fabbri LM, Sterk PJ, Di Maria GU, Geppetti P. Bronchoconstriction induced by citric acid inhalation in guinea pigs: role of tachykinins, bradykinin, and nitric oxide. AM J RESPIR CRIT CARE MED 1999;159:557‐562. Gastroesophageal acid reflux is more common in patients with asthma than in the general population, with an estimated
126 citations
TL;DR: Lys68 demonstrates good (thermo)stability properties that combined with different outer membrane permeabilizers, could become useful to combat Gram-negative pathogens in agricultural, food and medical industry.
Abstract: Resistance rates are increasing among several problematic Gram-negative pathogens, a fact that has encouraged the development of new antimicrobial agents. This paper characterizes a Salmonella phage endolysin (Lys68) and demonstrates its potential antimicrobial effectiveness when combined with organic acids towards Gram-negative pathogens. Biochemical characterization reveals that Lys68 is more active at pH 7.0, maintaining 76.7% of its activity when stored at 4°C for two months. Thermostability tests showed that Lys68 is only completely inactivated upon exposure to 100°C for 30 min, and circular dichroism analysis demonstrated the ability to refold into its original conformation upon thermal denaturation. It was shown that Lys68 is able to lyse a wide panel of Gram-negative bacteria (13 different species) in combination with the outer membrane permeabilizers EDTA, citric and malic acid. While the EDTA/Lys68 combination only inactivated Pseudomonas strains, the use of citric or malic acid broadened Lys68 antibacterial effect to other Gram-negative pathogens (lytic activity against 9 and 11 species, respectively). Particularly against Salmonella Typhimurium LT2, the combinatory effect of malic or citric acid with Lys68 led to approximately 3 to 5 log reductions in bacterial load/CFUs after 2 hours, respectively, and was also able to reduce stationary-phase cells and bacterial biofilms by approximately 1 log. The broad killing capacity of malic/citric acid-Lys68 is explained by the destabilization and major disruptions of the cell outer membrane integrity due to the acidity caused by the organic acids and a relatively high muralytic activity of Lys68 at low pH. Lys68 demonstrates good (thermo)stability properties that combined with different outer membrane permeabilizers, could become useful to combat Gram-negative pathogens in agricultural, food and medical industry.
126 citations
TL;DR: Some of the organic acids secreted by roots could play an important role in root colonization of SQR-21, and contributes to the understanding of the interactions of bacteria and plants under natural conditions.
126 citations
TL;DR: In this article, a citric acid assisted sol-gel method is employed for synthesizing LiNi0.6Co0.2O2 for use as a cathode material in lithium-ion batteries.
126 citations
TL;DR: A pre-plasticization step was necessary when incorporating triethyl citrate (TEC) into the formulation in order to achieve uniform mixing of the polymer and plasticizer, effectively reduce the polymer glass transition temperature (T(g)), and to lower the processing temperatures.
125 citations