离子对色谱法测定复方叶酸片中维生素B6、B12及叶酸的含量

目的:建立同时测定复方叶酸片中维生素B_6、B_(12)和叶酸含量的离子对色谱法。方法:色谱柱为日本TOSHO公司的ODS-80TS色谱柱(4.6 mm×150 mm,5 μm);流动相为乙腈-0.05 mol·L~(-1)磷酸二氢钾缓冲液(12:88,含3.88 mmol·L~(-1)四甲基溴化铵,pH 7.2),流速0.8 mL·min~(-1);检测波长为360 nm;进样量为20μL。结果:维生素B_6、B_(12)和叶酸分别在30.4～274.3 μg·mL~(-1)、0.87～2.6 μg·ml~(-1)和4.87～19.4μg·mL~(-1)范围内呈线性关系;相关系数分别为0.999 4,0.999 4,1.00O。平均回收率分别为99.6％(RSD=0.45％),99.7％(RSD=0.84％),99.5％(RSD=0.46％)。结论:本法可同时测定复方叶酸片中维生素B_6、B_(12)和叶酸的含量,方法简便、准确。     

石墨炉原子吸收法测定叶酸维生素B12注射液中的微量B12

使用石墨炉原子吸收法直接测定叶酸维生素B_(12)注射液中微量B_(12)的方法,其机理是维生素B_(12)中含有钴元素。该方法操作简便,不需分离,灵敏、快速而无干扰。实验中维生素B_(12)的平均回收率达100.9％,RSD为1.6％。     

高速液相层析法在天然有机化合物方面的应用

维生素(1)维生素A,D_2:填充剂:Corasil Ⅱ,移动相:氯仿;检测器:紫外。(2)维生素A,B_1,B_2,B_6,B_12:CorasilⅡ,1％异丙醇-异辛烷,紫外。(3)维生素A,E,A的异构体,未知成份:CorasilⅡ,1％异丙醇-异辛烷。     

封闭疗法治疗肌筋膜炎

1993年1月～1994年12月我所试用维生素B_1维生素B_(12)和普鲁卡因混合液(简称三联针),治疗肌筋膜炎,取得良好效果。本组196例,男80例,女116例,病程数小时～10年。治愈率95％。经注射1次治愈143例.占73％,其余病例经2～10次治疗而愈。 具体方法 局部常规消毒,用5毫升注射器抽取三联针液3～5毫升,按2％普鲁卡固2毫升,维生素B_1注射液2毫升(含B_1 100毫克),维生素B_(12)     

维生素B_1选择性电极的研究

本文研制以四间甲苯硼酸硫胺为活性物质的维生素B_1液膜电极。在pH2～4水溶液中的线性响应范围为10~(-1)～10~(-6)M。用柠檬酸复合底液可使维生素B_1的稳定范围扩展至pH8,电极灵敏度提高一倍(线性响应区斜率54mV/△pC)。由电极的线性响应斜率与pH的关系测出质子化硫胺在柠檬酸复合底液(I=0.5)中的pK_(a1)=5.04。电极响应快,稳定性好,适用于维生素B_1药物的快速分析     

让合理、安全用药知识(三十二) 走进千家万户

<正>(接上期)②震颤麻痹或肝昏迷患者在使用左旋多巴时禁止合用维生素B_6,因为维生素B_6可影响左旋多巴转化为多巴胺向血脑屏障的转移和利用,降低左旋多巴的疗效,故在使用左旋多巴治疗震颤麻痹或肝昏迷患者时,禁止合用维生素B_6。2.4维生素B_(12)的作用及其正确应用维生素B_(12)又叫钻胺素,是唯一含金属元素的维生素。自然界中的维生素B_(12)是由微生物合成的,高等动植物体内不能合成维生素B_(12)。维生素B_(12)也是唯一的一种需要肠道分泌物(内源因子)帮助才能被吸收的维生素。     

甲钴胺的药理及临床作用

甲钴胺为周围神经病变的治疗药物,属于维生素B_(12)类,别名为甲基维生素B_(12)。它通过促进神经细胞内核酸和蛋白质以及神经髓鞘的合成,从而修复受损伤的周围神经,目前已广泛应用于临床。从1948年Spies等人把维生素B_(12)作为药物研究以来,维生素B_(12)的研究取得飞速的发展,到目前为止,作为药物的维生素B_(12)主要有:氰钴胺、羟钴胺、腺苷钴胺和甲钴胺。前两种维生素B_(12)在人体内没有生物活性;后两种辅酶型维生素B_(12)已经实现人工合成,     

同型半胱氨酸和维生素B_(12)对急性脑梗死患者功能恢复的影响

<正>脑梗死是临床上常见的脑血管疾病。除了以往报道的因素外,高同型半胱氨酸血症、维生素B_(12)缺乏,以及甲状腺功能紊乱也是脑梗死危险因素~([1])。高同型半胱氨酸血症主要影响叶酸(维生素B_9)、维生素B_(12)和维生素B_6血清水平,从而增加脑梗死发生~([2])。人群中维生素B_(12)缺乏症检出率为10%～40%,可能有助于脑卒中和认知衰退~([3])。以往研究主要关注同型半胱氨酸和维生素B_(12)在脑卒中预     

小鼠口服维生素B_1,B_6,B_(12)的止痛作用

B族维生素在机体内有重要的生物功能, 临床研究已肯定,硫胺(维生素B_1)、吡多辛(维生素B_6)和氰钴铵(维生素B_(12))能缓解外周神经疾病和脊椎疾病引起的疼痛;人口服维生素B还能增强非类固醇类抗炎药物的止痛作用。在多种动物模型上已观察到,静脉、皮下或腹腔内注射维生素B_1,B_6或B_(12)具有止痛作用,但口服给药只有炎性止痛作     

维生素B_(12)与盐酸硫胺肌肉注射的配伍

据国內外文献报导,维生素的稳定性可因温度、pH值、原料纯度、助溶剂、各种维生素浓度间配比关系等因素可以改变。我们从临床需要出发,初步了解到维生素B_(12)和盐酸硫胺在临床上使用较多,且往往两者同时使用。医务人员为了避免患者分次注射的痛苦和操作上的方便,常将两种维生素混合进行注射。因此维生素B_(12)和盐酸硫胺肌肉注射配伍禁忌的探讨,成为临床需要解决的问题。本文首先通过盐酸硫胺对维生素B_(12)光密度值影响的测定,从实验结果表明维生素     

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.     

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.