C3,C4和CAM植物的光呼吸及有关酶活性的比较研究

对4种C_3植物和4种C_4植物,6种CAM植物的光呼吸的研究表明:C_4和CAM植物象C_3植物一样表现出断光后CO_2的猝发;它们的乙醇酸氧化酶活性远低于C_3植物,而过氧化氢酶活性略低于C_3植物;光下有乙醇酸的合成。我们认为在C_4和CAM植物中也存在光呼吸乙醇酸循环。C_4植物表观光呼吸的大小可能与其叶的解剖特征有关,而CAM植物的表观光呼吸可能与其代谢的昼夜节律变化有关。我们还研究了CAM植物的乙醇酸循环在早晨和傍晚的变化规律,发现绝大多数CAM植物的乙醇酸氧化酶活性、过氧化氢酶活性和乙醇酸的合成量都一致表现为傍晚高于早晨。我们认为CAM植物体内乙醇酸循环的运转傍晚较早晨快。     

氯化钠对小麦幼苗乙醇酸氧化酶活性和叶绿素含量的影响

本文报告氯化钠对小麦幼苗乙醇酸氧化酶的促进作用。试验结果表明,用氯化钠喷施小麦幼苗20小时后,乙醇酸氧化酶活性升高21％,体内蛋白质含量升高24.2％。用0.1、0.2、0.5mol/L的氯化钠培养幼苗,乙醇酸氧化酶活性分别比对照增加23％、61.1％和28.6％;蛋白质含量分别比对照增加12.8％、29.4％和18.1％;叶绿素含量分别下降2.8％、2.8％和22.2％。本文讨论了氯化钠影响乙醇酸氧化酶活性的机理。     

几种有机酸和氨基酸对乙醇酸氧化酶活性的影响

本文研究苹果酸、甘油酸、丝氨酸、谷氨酸对菜心(Brassica parachinensis Bailey)叶片乙醇酸氧化酶活性的影响。结果表明,苹果酸、丝氨酸和谷氨酸均对乙醇酸氧化酶起竞争性抑制作用,其中以苹果酸和丝氨酸的抑制作用较强而谷氨酸的抑制作用较弱;测定菜心乙醇酸氧化酶对乙醇酸的Km值为0.36m mol/L,丝氨酸、苹果酸、谷氨酸对乙醇酸氧化酶的Ki值分别为5.5,7.0,13.5m mol/L,甘油酸对乙醇酸氧化酶活性没有明显的影响,讨论了上述几种有机酸和氨基酸在乙醇酸途径代谢调节中的作用。     

在乙醇引起的血尿酸过高症中人参皂甙对黄嘌呤氧化酶活性的效应

现在已经广泛地认为人参活性成分如许多化学和药理学研究所揭示,是属于皂甙类化合物。在作者的试验中观察到人参皂甙能增加乙醇处理过的小鼠和大鼠肝的乙醇和乙醛氧化酶的活性,也观察了人参对酒精引起的血尿酸过高症的影响。用人参治疗酒精中毒的方法研究了血中尿酸水平的变化和肝的黄嘌呤氧化酶的活性。曾发现人参皂甙一次剂量4毫克/公斤腹腔给药时,明显地抑制肝的黄嘌呤氧化酶活性并降低因乙醇引起的血尿酸过多症的血中尿酸的水平。     

光对高等植物乙醇酸氧化酶的诱导

本文阐述了光对高等植物乙醇酸氧化酶活性的影响,分析了白光、光强度、光质等对酶的诱导作用,讨论了前人解释光的作用机制的几种学说,在此基础上提出了另一个光对乙醇酸氧化酶诱导机理的假说,认为光对该酶的诱导有两方面的作用,一是进行光合作用产生乙醇酸,乙醇酸诱导酶蛋白合成;二是光促进体内FMN的生物合成与还原。所合成的酶蛋白再与FMN结合成全酶而表现出催化活性。     

染料木素、芹菜素、槲皮素、芦丁和落新妇苷对高尿酸血症小鼠黄嘌呤氧化酶活性及血清尿酸水平的影响

目的探讨黄酮类化合物染料木素、芹菜素、槲皮素、芦丁和落新妇苷体外对黄嘌呤氧化酶活性的影响,对高尿酸血症小鼠血清和肝脏黄嘌呤氧化酶活性的影响,同时评价对小鼠血清尿酸水平的作用。方法采用改良的紫外分光光度法测定染料木素、芹菜素、槲皮素、芦丁和落新妇苷体外对黄嘌呤氧化酶的抑制作用;采用尿酸酶抑制剂氧嗪酸钾诱导小鼠高尿酸血症模型,以分光光度法研究对小鼠血清和肝脏黄嘌呤氧化酶活性的影响,以磷钨酸法测定对小鼠血清尿酸水平的作用。结果体外实验表明这些黄酮类化合物对黄嘌呤氧化酶活性无明显影响。然而,体内实验观察到能够明显升高或降低黄嘌呤氧化酶的活性,而且,血清尿酸水平与血清黄嘌呤氧化酶活性密切相关,与肝脏黄嘌呤氧化酶活性无明显关联。该研究表明用这些黄酮类化合物给药的小鼠血清尿酸水平都高于正常对照组。结论这5种黄酮类化合物不能够作为替代别嘌醇的药物用来降低血清尿酸水平。     

西红花酸体内外抗氧化作用的研究

目的研究西红花酸体内外抗氧化作用,以探讨其抗AS作用机制。方法采用次黄嘌呤/黄嘌呤氧化酶反应体系产生O2-,观察西红花酸对O2-的清除作用;分离LDL,观察西红花酸对铜离子诱导的LDL氧化的影响;大鼠灌胃给予西红花酸,观察其对血清TAC及SOD、GPX等抗氧化酶活性、血清氧化易感性的影响。结果西红花酸能有效清除次黄嘌呤/黄嘌呤氧化酶反应体系产生的O2-,抑制铜离子诱导的LDL氧化修饰。西红花酸能明显提高大鼠血清SOD、GPX等抗氧化酶活性,提高血清抗氧化能力。结论西红花酸具有良好的体内外抗氧化活性,能明显提高血清及LDL抗氧化能力,这可能是其抑制AS主要机制之一。     

染料木素等5种黄酮类物质对小鼠血清尿酸水平及黄嘌呤氧化酶活性的影响

目的探讨黄酮类化合物染料木素、芹菜素、槲皮素、芦丁和落新妇苷体外对黄嘌呤氧化酶活性的影响,对正常小鼠血清和肝脏黄嘌呤氧化酶活性的影响,同时评价对小鼠血清尿酸水平的作用。方法采用改良的紫外分光光度法测定染料木素、芹菜素、槲皮素、芦丁和落新妇苷体外对黄嘌呤氧化酶的抑制作用,采用分光光度法研究对小鼠血清和肝脏黄嘌呤氧化酶活性的影响,以磷钨酸法测定对小鼠血清尿酸水平的作用。结果体外实验表明黄酮类化合物染料木素、芹菜素、槲皮素、芦丁和落新妇苷体外对黄嘌呤氧化酶活性无明显影响。体内实验观察到这5种黄酮类化合物能够显著升高或降低黄嘌呤氧化酶的活性;而且,血清尿酸水平与血清黄嘌呤氧化酶活性密切相关,与肝脏黄嘌呤氧化酶活性无明显关联。用这些黄酮类化合物给药的小鼠血清尿酸水平都高于正常对照组。结论这5种黄酮类化合物不能够作为替代别嘌醇的药物用来降低血清尿酸水平。     

木香70%乙醇提取物对缺氧小鼠肝保护作用

目的正常的线粒体膜电位是维持线粒体氧化磷酸化、产生三磷酸腺苷的先决条件,研究木香70%乙醇提取物对模拟高原低氧小肝脏线粒线粒体膜电位、三羧酸循环和糖酵解关键酶的影响,从线粒体功能角度探讨其对肝保护作用机制。方法雄性BALB/c小鼠随机分成6组:空白对照组、低氧模型组、阳性组(ACZ,300 mg·kg~(-1),ip)、木香70%乙醇提取物低剂量组(125 mg·kg~(-1))、中剂量组(250 mg·kg~(-1))、高剂量组(375 mg·kg~(-1)),连续给药5 d,末次给药1 h后缺氧72 h,麻醉处死,提取肝脏线粒体,测定线粒体膜电位;肝组织匀浆,测定线粒体复合物Ⅰ、Ⅱ和苹果酸脱氢酶、顺乌头酸酶、α-酮戊二酸脱氢酶活性。结果与正常对照组比较,模型组线粒体膜电位、顺乌头酸酶活性、ɑ-酮戊二酸脱氢酶活性、呼吸链复合体Ⅰ活性、呼吸链复合体Ⅱ活性显著降低(P<0.05);与模型组比较,木香乙醇提取物低、中、高剂量组线粒体膜电位、顺乌头酸酶活性、ɑ-酮戊二酸脱氢酶活性、呼吸链复合体Ⅰ活性、呼吸链复合体Ⅱ活性升高,高剂量组均显著升高(P<0.05)。与正常对照组比较,模型组线粒体苹果酸脱氢酶活性升高;与模型组比较,木香乙醇提取物高剂量组线粒体苹果酸脱氢酶活性显著降低(P<0.05)。结论木香70%乙醇提取物能够保护线粒体膜电位,提高顺乌头酸酶、ɑ-酮戊二酸脱氢酶、苹果酸脱氢酶和线粒体复合物Ⅰ、Ⅱ的活性,具有保护低氧小鼠肝线粒体功能的活性。     

痛风颗粒各部位对高尿酸血症大鼠尿酸和黄嘌呤氧化酶活性的影响

目的 通过观察痛风颗粒各部位对高尿酸血症大鼠血尿酸、尿尿酸、血黄嘌呤氧化酶活性和肝脏黄嘌呤氧化酶活性的影响,探讨其治疗痛风的物质基础和机制.方法 以腺嘌呤合乙胺丁醇法诱导大鼠高尿酸血症模型,分别用磷钨酸法和酶比色法检测尿酸和黄嘌呤氧化酶的含量.结果 黄酮类成分在降尿酸和抑制黄嘌呤氧化酶活性上均起主要作用;生物碱类成分对尿中尿酸的排泄和血清黄嘌呤氧化酶活性的抑制起较重要作用,有机酸类成分均未表现出明显作用;全方和有效部位组合有明显的降尿酸和抑制黄嘌呤氧化酶活性的作用.结论 黄酮类、生物碱和有机酸类有效部位组合后的药效与处方药一致,是该处方的有效部位群,对高尿酸血症模型大鼠表现出的降尿酸和抑制黄嘌呤氧化酶活性的作用最为显著.     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

---

Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.