共查询到20条相似文献,搜索用时 93 毫秒
1.
氟喹诺酮类抗生素属于喹诺酮类抗生素,是一类人畜通用的抗生素。近年来,被广泛应用于人类和畜牧、水产等养殖业领域,然而其大量使用,造成在环境中的不断残留和累积,给自然环境和人类健康造成了较大威胁。现有研究表明,微生物降解是有效去除氟喹诺酮类抗生素残留污染的有效方法之一。本文总结和介绍了近年来氟喹诺酮类抗生素微生物降解单株菌和混合菌群、微生物降解酶、降解途径以及微生物降解氟喹诺酮类抗生素的实际应用,并对目前氟喹诺酮类抗生素微生物降解研究中存在的问题进行了分析,以及对未来氟喹诺酮类抗生素微生物降解研究的重点进行了探讨,以期为后续的研究提供参考。 相似文献
2.
3.
4.
结核病是由结核分枝杆菌(Mycobacterium tuberculosis)通过空气传播引起人类感染的慢性传染病,耐药结核分枝杆菌的流行是目前结核病防治的世界难题。氟喹诺酮类药物是人工合成药物,应用于耐药结核的临床治疗中,在治疗中起着核心的作用。但近年来,氟喹诺酮类药物的抗性菌株不断出现,愈发增加了结核病治疗的困难与治疗失败风险。在临床中氟喹诺酮药物的靶点比较清楚,是结核分枝杆菌的DNA旋转酶。目前发现结核分枝杆菌耐氟喹诺酮类药物的机制主要包括药物靶点DNA旋转酶的关键氨基酸改变、药物外排泵系统、细菌细胞壁厚度的增加以及喹诺酮抗性蛋白MfpA介导的DNA旋转酶活性调控。其中在氟喹诺酮靶标DNA旋转酶功能活性改变的耐药机制方面,编码DNA旋转酶基因突变一直是研究的热点,但近年来发现DNA旋转酶的调控蛋白MfpA以及DNA旋转酶的修饰在细菌耐药性中起着重要的作用,相关机制还亟待发现。本文综述了当前结核分枝杆菌耐氟喹诺酮类药物的作用机制,旨在为研发精准诊断技术和药物发掘提供科学理论基础和参考。 相似文献
5.
目的研究肺炎克雷伯杆菌对氟喹诺酮类药物(FQNs)的耐药机制。方法筛选临床分离的对环丙沙星耐药的肺炎克雷伯杆菌共10株,采用微量肉汤稀释法检测菌株对5种氟喹诺酮类药物的MIC值;采用PCR方法检测菌株染色体和质粒携带的喹诺酮耐药基因(gyrA基因、parC基因和qnr基因)并测序;质粒接合试验验证qnr基因的转移性。结果 10株肺炎克雷伯杆菌对5种氟喹诺酮类药物均产生耐药性。扩增产物经测序发现10株肺炎克雷伯杆菌染色体的gyrA基因和parC基因均有突变;有2株菌株(K79和K107)携带qnrA基因,这2株菌的接合菌对喹诺酮抗菌药的MIC值上升了5~30倍;未检测到qnrB阳性的菌株。结论 gyrA和parC基因突变是肺炎克雷菌对氟喹诺酮类产生耐药机制的主要原因,质粒上qnrA基因的存在,也是产生喹诺酮耐药的一个重要因素。 相似文献
6.
7.
目的了解玉溪市1999年至2008年甲型副伤寒患者肠沙门菌甲型副伤寒血清型(SPA)分离株的萘啶酸抗性和克隆扩散。方法采用有对照的K-B纸片扩散技术对4060株SPA进行抗微生物药物敏感性试验;对随机选择的166个萘啶酸抗性(NAR)株和20个萘啶酸敏感(NAS)株进行SpeI消化染色体DNA脉冲场凝胶电泳(PFGE)分型、聚类分析以及氟喹诺酮最小抑菌浓度(MIC)测定。结果分离株的NAR率由1999年的12.5%、2000年82.2%、2001年93%上升到2008年的100%;NAS株在1999年占优势,但在2000年以后被NAR株替代;166个NAR株都降低了对氟喹诺酮类药物的敏感性,其MIC值比20个NAS株的高得多。186个菌株SpeI消化产物得出以SpeI01、SpeI02型占优势的9种PFGE型。结论萘啶酸筛检实验可用于检测SPA降低氟喹诺酮敏感性,SpeI01和SpeI02是玉溪流行的主要克隆,建议制定并实施氟喹诺酮药物抗性株引起爆发流行的处理方案。 相似文献
8.
目的了解临床分离铜绿假单胞菌对喹诺酮类等抗菌药物的耐药性。方法琼脂稀释法测定86株铜绿假单胞菌对5种氟喹诺酮类抗菌药物以及头孢吡肟、美罗培南的耐药性。结果铜绿假单胞菌对诺氟沙星、氧氟沙星、左氧氟沙星、环丙沙星、加替沙星的耐药率分别为50%、61.6%、51.2%、48.8%、51.2%;对头孢吡肟和美罗培南的耐药率分别为30.2%、23.2%。结论铜绿假单胞菌对氟喹诺酮类抗菌药物耐药显著,临床应加强检测和监测。 相似文献
9.
10.
11.
We used a combined biochemical and histocytochemical approach to study ecto-ATPase in the rat cardiac muscle. The reaction medium employed for histocytochemical detection was optimized in biochemical assays to achieve the highest enzyme activity and lowest inhibition by the capture agent used for visualization of the reaction product. Approximately 70% of the enzyme activity was retained in samples after the fixation procedure. Divalent cations stimulated ecto-ATPase. High activity was detectable within a wide pH range. Histocytochemical reaction was observed at sites at which extracellular ATP can potentially exert its actions on the cardiac muscle: nerve endings, plasma membranes of cardiac myocytes and capillary endothelial cells, and T-tubules. Product of the reaction was found exclusively at the outer surface of the cells. In controls, enzyme activity was abolished by diethyl pyrocarbonate and slightly stimulated by digitonin and concanavalin A, whereas sodium orthovanadate, N-ethylmaleimide, and sodium azide yielded no effect. Our results support the view that cardiac ecto-ATPase is involved in important physiological functions and suggest that its activity may be regulated by the release of ATP from nerve endings. 相似文献
12.
Walter E. Garrey 《The Journal of general physiology》1920,3(1):49-56
1. It is possible to determine by the colorimetric method the rate of production of carbon dioxide by the cardiac ganglion of Limulus. 2. Carbon dioxide formation in the cardiac ganglion was found to run parallel to the rate of heart beat for different temperatures. 3. The conclusion seems justified that the rate of cardiac rhythm of Limulus depends upon a chemical reaction in the nerve cells of the cardiac ganglion and that this reaction is associated with the production of carbon dioxide since the rate of beat and the rate of CO2 production are similarly affected by changes in temperature. 相似文献
13.
Yihai Liu Jiamin Xu Mingyue Wu Lina Kang Biao Xu 《Journal of cellular physiology》2020,235(12):8996-9004
The cardiac repair after myocardial infarction (MI) involves two phases, namely, inflammatory response and proliferative response. The former is an inflammatory reaction, evoked by different kinds of pro-inflammatory leukocytes and molecules stimulated by myocardial necrosis, while the latter is a repair process, predominated by a magnitude of anti-inflammatory cells and cytokines, as well as fibroblasts. Cardiac remodeling post-MI is dependent on the balance of individualized intensity of the post-MI inflammation and subsequent cardiac fibrosis. During the past 30 years, enormous studies have focused on investigating immune cells and mediators involved in cardiac inflammation and fibrosis, which are two interacting processes of post-MI cardiac repair. These results contribute to revealing the mechanism of adverse cardiac remodeling after MI and alleviating the impairment of cardiac function. In this study, we will broadly discuss the role of immune cell subpopulation and the involved cytokines and chemokines during cardiac repair post-MI, particular in cardiac inflammation and fibrosis. 相似文献
14.
Reaction rates of creatine kinase and ATP synthesis in the isolated rat heart. A 31P NMR magnetization transfer study 总被引:8,自引:0,他引:8
The NMR technique of magnetization transfer can be used to define intracellular reaction kinetics. In order to determine the relationship between ATP synthesis and flux through the creatine kinase reaction in the intact heart, we used this technique to measure flux through the creatine kinase reaction in the isolated, isovolumic rat heart at five levels of cardiac performance and oxygen consumption. The unidirectional reaction rate constants (s-1) calculated from a two-site exchange model for both the forward and reverse creatine kinase reactions increased with cardiac performance and oxygen consumption. As the rate-pressure product varied from 0 to 44.7 X 10(3) mm Hg/min and oxygen consumption rose from 5.9 to 45.8 mumol of O2/g dry weight/min, kforward increased from 0.27 to 1.30 and kreverse increased from 0.31 to 1.14. The relationship between creatine kinase flux and oxygen consumption, and thus ATP synthesis, took the form of the Michaelis-Menten equation. Rates of ATP synthesis estimated from magnetization transfer were similar to values calculated from oxygen consumption. The longitudinal relaxation time of creatine phosphate (2.06 s), the gamma-phosphorus atom of ATP (0.75 s), and inorganic phosphate (0.81 s) did not change with cardiac performance. These results show that myocardial energy transfer via the creatine kinase reaction is closely coupled to energy production. 相似文献
15.
《Journal of liposome research》2013,23(1-2):3-14
Intravenous administration of liposomes, including Doxil, can cause severe life-threatening hemodynamic changes in pigs. The reaction is due to complement activation, and it is characterized by massive pulmonary hypertension, systemic hypotension, and severe cardiac abnormalities including falling cardiac output, tachy-or bradycardia with arrhythmia. There were no data suggesting the involvement of cerebrovascular changes in this reaction; however, clinical observations allowed this hypothesis. Here we measured the accompanying changes during liposome infusion by monitoring pulsatile electrical impedance (rheoencephalogram- REG) on the skull (n = 24 pigs, 57 trials, 19 types of liposomes). A transient but significant decrease of REG pulse amplitudes followed the injection of liposomes (78.43% in the total sample, and 91.66% in the Doxil subgroup; P = 0.003, n = 12), indicating the involvement of cerebrovascular reaction during liposome infusion. 相似文献
16.
《Indian pacing and electrophysiology journal》2023,23(1):21-22
Contact allergy to implantable cardiac defibrillators (ICD) is an uncommon and underdiagnosed complication. We report a case of a 20-years-old man patient that was resuscitated from sudden cardiac death. Workup imaging study was unremarkable, but genetic testing identified a mutation in the KCNH2 gene of uncertain significance. The patient underwent a subcutaneous implantable cardiac defibrillator (S-ICD) implantation, with no complications. The patient suffered two hospital re-admissions due to a device-related inflammatory reaction, leading to two device re-implantations. At the first time, it was considered a bacterial infection and the S-ICD was replaced by an endovascular device. At the second time, a tissue-device interaction, with hypersensitivity reaction and device rejection was suspected. The skin patch-tests were inconclusive, but it was decided to implant a custom-made gold-coated endovascular ICD. Indeed, the tendency is an initial misdiagnosis as an infection and a high clinical suspicion is essential to an early diagnosis. 相似文献
17.
It has been established that in lesion of the myocardium accumulation of huge amount of algesic compounds may cause limitation of the level of cardiac afferentation. Use of naloxone, buterfanol tartrate and D-ala-2-lei-enkephalin prevent the development of the reaction. The possibility of participation of the endogenic cardiac opioids in anti-nociceptive reactions of heart during its lesion is considered. 相似文献
18.
Bodo M Szebeni J Baranyi L Savay S Pearce FJ Alving CR Bünger R 《Journal of liposome research》2005,15(1-2):3-14
Intravenous administration of liposomes, including Doxil, can cause severe life-threatening hemodynamic changes in pigs. The reaction is due to complement activation, and it is characterized by massive pulmonary hypertension, systemic hypotension, and severe cardiac abnormalities including falling cardiac output, tachy-or bradycardia with arrhythmia. There were no data suggesting the involvement of cerebrovascular changes in this reaction; however, clinical observations allowed this hypothesis. Here we measured the accompanying changes during liposome infusion by monitoring pulsatile electrical impedance (rheoencephalogram- REG) on the skull (n=24 pigs, 57 trials, 19 types of liposomes). A transient but significant decrease of REG pulse amplitudes followed the injection of liposomes (78.43% in the total sample, and 91.66% in the Doxil subgroup; P=0.003, n=12), indicating the involvement of cerebrovascular reaction during liposome infusion. 相似文献
19.
20.
Distribution of isomyosin in cultured cardiac myocytes as determined by monoclonal antibodies and adenosine triphosphatase activity 总被引:1,自引:0,他引:1
The distribution of isomyosin in cardiac muscle cells in culture has been investigated with monoclonal antibodies and Ca2+-activated myosin ATPase cytochemical staining. With immunofluorescent studies using monoclonal antibodies to isomyosins V1 and V3, the cardiac myocytes grown in a serum-free and thyroxine (T4)-free medium for 7 days contained a predominant population of cells which were strongly reactive to anti-V3 antibody. A small population of myocytes in this culture exhibited weak or no reaction to anti-V3 antibody. When cultures were exposed to anti-V1 antibody, the predominant cardiac myocyte population showed little or no reactivity to this antibody, whereas a small population of the myocytes were strongly reactive. The myosin ATPase staining reaction of the positive myocyte population was significantly less pronounced than that of the V3-negative population which showed a strong reaction. The staining pattern changed dramatically after exposure of cultured myocytes to thyroid hormone for 7 days. Most of the cells were found to react strongly with anti-V1 antibody, while some cells showed little reactivity and some were not stained at all. A small number of cardiac myocytes in this culture showed little or no reactivity to anti-V1 antibody but were strongly reactive to anti-V3 antibody. The predominant anti-V1-positive myocyte population exhibited strong myosin ATPase staining as compared to a smaller V3-positive myocyte population which showed very weak staining. The cytochemical results of ATPase staining in cardiac myocytes agreed well with ATPase activity as determined on pyrophosphate gels containing isomyosin derived from cultured cardiac myocytes with or without T4. This study has demonstrated that cultured myocytes contain a small population of muscle cells which is not responsive to thyroid hormone or to the lack of it. 相似文献