从蚕砂中制备脱镁叶绿酸的工艺研究

目的 :优化以蚕砂为原料制备脱镁叶绿酸工艺条件 ,提高产出率。方法 :以叶绿素提取率为指标 ,对脱镁叶绿酸制备的乙醇法和丙酮法工艺进行比较 ,用正交试验法对丙酮法的工艺条件进行优化。结果 :脱镁叶绿酸的最佳制备条件为蚕砂粉碎度60目 ,加1/10倍药材量的水软化5h以上 ,加3倍药材量的溶媒 ,提取温度70℃ ,回流时间60min ,提取次数2次 ,酸化时 pH调至2 5。结论 :软化水用量、丙酮量对叶绿素提取率影响较大 ,经优化后可提高丙酮法制备脱镁叶绿酸的产出率4 6倍     

蚕沙叶绿素提取及合成脱镁叶绿酸工艺改进研究

目的探讨不同提取工艺对蚕沙中提取叶绿素及制取叶绿素衍生物脱镁叶绿酸的影响,以提高蚕沙叶绿素及叶绿素衍生物的制备量。方法单因素实验设计,以蚕沙软化时间(含水量)、不同提取溶剂为考察条件,优化蚕沙叶绿素提取工艺,并探讨浓盐酸脱镁时间对叶绿素合成脱镁叶绿酸制备率的影响。结果蚕沙软化时间2 h(含水量26%)、丙酮∶乙醇体积比1∶1做溶剂为提取叶绿素的最佳条件,提取率提高到1.43%。以蚕沙叶绿素粗品合成叶绿素衍生物脱镁叶绿酸,浓盐酸脱镁搅拌反应72 h制备率达670 mg.g 1。结论通过改良工艺,提高了蚕沙叶绿素及其衍生物脱镁叶绿酸的提取制备率。     

双反浮选工艺在胶磷矿选别中的应用

根据云南某磷矿的性质,采用双反浮选工艺处理胶磷矿,在酸性条件下先用阴离子捕收剂反浮选脱镁,脱镁精矿再用阳离子捕收剂反浮选脱除硅酸盐杂质.结果表明:经过双反浮选可得到精矿W(P2O5)>30%、w(MgO)<0.4%,磷回收率大于72%的选别指标.     

镁肥的施用

1　我国土壤缺镁状况地壳中镁的平均含量为 2 3 5 % ,而土壤中镁的平均含量只有0 6% ,这是由于镁易被淋溶的结果 ,我国北方土壤平均含镁量 1% ,南方土壤平均含镁量为 0 5 % ,所以南方土壤比北方土壤更加缺镁。全国土壤普查结果表明 ,我国土壤缺镁严重 ,缺镁土壤面积达5 5 3 3万hm2 ,占全国耕地总面积约 6%。2　镁肥的需求全国缺镁土壤每公顷施用镁肥 15 0kg ,则年需求量为 80 0kt,其它喜镁作物需镁肥 5 0 0kt,则年需镁肥 13 0 0kt。3　镁肥资源及品种( 1)　我国镁资源情况我国镁资源十分丰富 ,菱镁矿储量 10亿t,白云石储量几十亿吨 ,水…     

正交实验设计优化二氢卟吩f的制备反应条件

用正交设计法优化了二氢卟吩 f的合成。实验表明 ,将 6 .0 g未经分离纯化的脱镁叶绿酸 a粗品 ( HPL C检测纯度为5 5 % ,5 .5 7mmol)和 2 40 ml 30 %氢氧化钾甲醇液在 0℃下通 O2 氧化反应 1h后再于通 N2 条件下迅速煮沸回流脱羧反应 0 .5 h得 5 .4g二氢卟吩 f粗品 ( HPLC检测纯度为 5 8.7% ) ,经硅胶 H柱色谱分离得 1.1g纯品 ( HPLC检测纯度为 98% ) ,产率达 36 .7%。     

脱镁叶绿环类衍生物的分离,制备及鉴定

自蚕砂糊状叶绿素分得的叶绿素 a(1),于不同条件下经酸降解、脱羧焦化、甲酯化、氧化,在各步中可得脱镁叶绿素 a(2)、脱镁叶绿酸 a(3),焦脱镁叶绿酸 a(4)、甲基脱镁叶绿酸 a(5)、甲基焦脱镁叶绿酸a(6)、10-羟基甲基脱镁叶绿酸 a(7)和红紫素7-内酯二甲酯(8)。7和8的 ~1HNMR 和 MS 数据为首次报道。     

沉淀法净化湿法磷酸反应机理的研究

探讨用湿法磷酸制饲料级磷酸氢钙时，采用沉淀法净化湿法磷酸的反应机理。着重介绍镁对产品质量的影响，脱镁过程的控制和脱镁反应动力学；氟在湿法磷酸中的赋存状态，脱氟反应过程和脱氟反应机理。     

晕宁颗粒的提取工艺研究

目的：优选晕宁颗粒提取工艺。方法：用正交设计试验优选水和醇提工艺条件。结果：乙醇提取的最佳条件：8倍量70％乙醇提取3次，每次2h；水提取的最佳条件：加10倍量水，浸泡0．5h，提取2次，每次1．5h。结论：本工艺稳定可行，为晕宁颗粒提取工艺的优选提供了依据。     

微波消解-火焰原子吸收分光光度法测定三层共挤输液用袋中镁残留量及迁移量

目的 建立三层共挤输液用袋材料中镁残留量及输液袋中镁迁移量的微波消解-火焰原子吸收分光光度法。方法 采用微波消解对样品进行消解处理,以火焰原子吸收光谱法测定样品中镁含量。结果 镁在0~0.30 μg·mL^-1内呈良好的线性关系(r=0.995 2);镁含量测定的平均回收率为95.95%(RSD=2.27%)。结论 该方法准确、灵敏、简便,适用于对三层共挤输液用袋材料中镁残留量及镁向输液中迁移量的测定。     

水杨酸镁对胎鼠脑细胞内钙的影响

目的　观察水杨酸镁对脑细胞内钙的影响 ,探讨其中枢神经系统的钙拮抗作用。方法　应用新一代钙离子指示剂Fura 2 /AM技术 ,用双波长荧光分光光度计测定细胞内钙浓度。结果　在不同外钙条件下 (外钙 0 ,0 0 1,0 1,1 0 ,1 3mmol·L-1)细胞内静息钙浓度分别 41± 5 ,5 9± 6 ,84 7± 2 5 ,10 4± 7,(12 6± 5 )nmol·L-1(各组n =8)。水杨酸镁0 2mmol·L-1对静息细胞内钙无显著影响 (P >0 0 5 )。但水杨酸镁 (0 0 5～ 0 4mmol·L-1)可以剂量依赖性抑制高钾及L 谷氨酸诱发的细胞内钙增高。其IC50 分别为 0 32 3mmol·L-1(95 %CI为 0 12 2～ 0 85 4mmol·L-1)和 0 12 4mmol·L-1(95 %CI为 0 0 73～ 0 2 10mmol·L-1)。结论　水杨酸镁通过抑制电压依从性及受体操纵型的钙通道 ,对中枢神经系统具有较强的钙拮抗作用。     

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.

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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.     

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.     

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.     

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.     

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.