雄黄及含雄黄复方中砷含量、形态和晶形分析

目的 对雄黄及含雄黄复方制剂中的砷含量、砷形态和雄黄晶形进行分析.方法 采用微波消解-原子荧光法测定雄黄和复方制荆中的总砷含量,人工胃液提取.原子荧光法测定可溶性砷,离子树脂交换分离.原子荧光法测定可溶性三价砷(AⅢ)和五价砷(AsV),X衍射荧光法对雄黄粉末进行物相(晶形)分析,X荧光光谱法进行雄黄粉末的全元素分析.结果 受试雄黄含硫化砷97.3%,主成分是β-雄黄(As4S4)和α-雄黄(AsS)的混合物,同时含有少量二硫化二砷(As2S2)和雌黄(As2S3).As/S(摩尔数之比)为1.00001.还含有少量Al、Si、K、Ca、Ti、Fe、Sb、Ni、Cu、W等杂质.在雄黄及含雄黄复方制剂的人工胃液提取液中均检出了可溶性砷、AsⅢ和AsV;且不同来源的雄黄,可溶性砷以及两种价态的砷的比例也不同.雄黄中可溶性砷百分含量为0.62%,其中AsⅢ和AsV比例为2.30:1.结论 雄黄及含雄黄复方中混杂存在三价和五价无机砷.有必要加强对雄黄药材的质量监控.     

局方至宝丸中雄黄的含量测定

目的建立局方至宝丸中雄黄的含量测定方法。方法采用原子吸收分光光度法测定雄黄中砷的含量。结果原子吸收分光光度法测定砷的线性范围为0~16 ng·mL~(-1)(r=0.9973);平均回收率为99.1%~107.0%,RSD为0.87%~5.4%(n=3)。结论所建方法专属性强,重复性好,可用于局方至宝丸中雄黄的质量控制。     

安宫牛黄散中配伍药物对雄黄可溶性砷含量的影响

目的以安宫牛黄散为实例,研究中药复方中的配伍药物对雄黄中砷的溶解性的影响. 方法安宫牛黄散中几种单味药与雄黄混合用人工胃液处理,用原子荧光法测定可溶性砷的含量.结果安宫牛黄散中几种单味药分别与雄黄混合用人工胃液处理后,测得的可溶性砷含量均比雄黄在人工胃液中的可溶性砷的溶出量低,使可溶性砷含量溶出减少的单味药次序依次为黄芩、黄连、珍珠、栀子、郁金和牛黄,溶出的可溶性砷含量依次减少55.1%,49.3%,29.4%,25.2%,25.0%和11.4%(P<0.01).安宫牛黄散中的可溶性砷含量比雄黄的可溶性砷含量减少35.3%(P<0.01).结论安宫牛黄散中的几种单味药均有抑制雄黄中可溶性砷溶出的作用,推测是降低砷的毒性作用的可能途径之一.     

双黄清喷剂中雄黄的含量测定及可溶性砷盐检查

目的:研究双黄清喷剂中雄黄的含量测定及可溶性砷盐检查.方法:分光光度法对双黄清喷剂中雄黄的含量进行测定,采用砷盐检查法测定本品中含砷量.结果:含砷量在4～20μg范围线性关系良好(r=0.9994)回归方程为Y=0.0308X+0.0293,平均回收率为(99.30±1.33)%.结论:分光光度法测定双黄清喷剂中三氧化二砷(As2O3)简便、准确、重现性好,可作为该制剂质量检验的定量方法.     

牛黄解毒片中不同单味组分对雄黄可溶性砷含量影响的比较研究

目的研究牛黄解毒片中各单味组分对雄黄可溶性砷含量的影响。方法采用雄黄与牛黄解毒片中的7种单味药按牛黄解毒片处方比例分别组方分为9组供试品并经人工胃液处理后,用分光光度法分别测定可溶性砷的含量。结果与雄黄组相比,雄黄与处方中各组分单独组方后测得的可溶性砷含量均有不同程度降低。其中大黄+雄黄组和甘草+雄黄组使可溶性砷含量减少为84.9%和81.1%,而冰片+雄黄组等影响不显著。结论牛黄解毒片中的大黄、甘草等与雄黄配伍能较显著地抑制雄黄中可溶性砷的溶出,为进一步探讨雄黄复方中影响可溶性砷盐的主要物质提供参考依据。     

Plackett-Burman和Box-Behnken设计优化提取雄黄中的可溶性砷

目的利用Plackett-Burman和Box-Behnken设计优化雄黄中可溶性砷的提取工艺。方法采用Plackett-Burman设计实验,以雄黄中可溶性砷的提取率为指标,筛选出影响雄黄中可溶性砷提取率的3个显著影响因素:温度、时间、提取次数。在此基础上,通过Box-Behnken响应面法对筛选出的显著影响因素进一步优化,实验数据通过Minitab软件进行多元线性回归和二项式拟合,并应用响应优化器对实验结果进行优化和预测分析。结果以水作为提取溶剂,雄黄中可溶性砷的最佳提取工艺为雄黄15 mg,水10 m L,提取温度80℃,超声提取3次,每次60 min。结论采用Plackett-Burman和BoxBehnken设计及响应面法优化提取雄黄中可溶性砷的提取率,优选出的提取工艺稳定可靠,实验精度高,与模型预测值基本一致。     

安宫牛黄散中配伍药物对雄黄可溶性砷含量的影响

目的以安宫牛黄散为实例,研究中药复方中的配伍药物对雄黄中砷的溶解性的影响。方法安宫牛黄散中几种单味药与雄黄混合用人工胃液处理,用原子荧光法测定可溶性砷的含量。结果安宫牛黄散中几种单味药分别与雄黄混合用人工胃液处理后,测得的可溶性砷含量均比雄黄在人工胃液中的可溶性砷的溶出量低,使可溶性砷含量溶出减少的单味药次序依次为黄芩、黄连、珍珠、栀子、郁金和牛黄,溶出的可溶性砷含量依次减少55.1%,49.3%,29.4%,25.2%,25.0%和11.4%(P<0.01)。安宫牛黄散中的可溶性砷含量比雄黄的可溶性砷含量减少35.3%(P<0.01)。结论安宫牛黄散中的几种单味药均有抑制雄黄中可溶性砷溶出的作用,推测是降低砷的毒性作用的可能途径之一。     

雄黄和六神丸中可溶性砷的溶出度研究

目的建立高效液相色谱-电感耦合等离子体质谱联用技术(HPLC-ICP-MS)法测定单味雄黄和六神丸可溶性砷的含量方法;考察六神丸配伍对雄黄中可溶性砷溶出度的影响,探讨六神丸的配伍机制。方法分别建立了ICP-MS和HPLCICP-MS法测定雄黄及六神丸中总砷和可溶性砷含量的方法,采用人工胃液和人工肠液为溶出介质,考察雄黄和六神丸中可溶性砷的溶出情况,分析配伍使用对雄黄中可溶性砷溶出的影响。结果 5种不同形态砷标准物质在5~500μg·L-1内线性关系良好,精密度和重复性均良好,回收率89%~102%。可溶性砷从六神丸复方中的溶出量和溶出速率均明显低于从单味雄黄中的溶出。结论六神丸复方配伍可显著降低雄黄中可溶性砷的溶出,从而降低其毒性。     

石墨炉原子吸收分光光度法测定雄黄和牛黄解毒片中可溶性砷的含量

目的:建立测定雄黄和牛黄解毒片中可溶性砷的含量,完善中药中砷含量测定的方法。方法:采用稀盐酸和人工胃液2种溶剂分别提取雄黄、牛黄解毒片中的可溶性砷,加入基体改进剂,用石墨炉原子吸收分光光度法测定砷的含量。光源发射波长:光度呈良好的线性关系(r=0.999 0);平均回收率分别为99.20%、98.67%、100.77%,RSD=2.01%。结论:本方法简单、快速、准确,可作为中药中微量水溶性砷的含量测定方法。     

雄黄及含雄黄中成药中砷的形态分析

目的:建立一种中药中砷的形态分析方法,分离并测定雄黄及含雄黄中成药中4种形态的砷化合物:无机 As(Ⅲ)、As(V)和有机单甲基胂酸(MMA)、二甲基胂酸(DMA)。方法:以稀盐酸溶液(pH 2)浸提雄黄及含雄黄中成药中的可溶性砷,用阴、阳离子固相萃取小柱进行分离,氢化物发生-原子荧光光谱法测定4种形态砷含量。结果:4种形态砷能实现完全分离,测定精密度、准确度良好。结论:本方法较为简便,准确、可靠,适用于分离测定雄黄及含雄黄的中成药中4种形态砷含量。     

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.

     

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.     

2-(Acetoxyphenyl)-(Z)-styryl sulfides as cyclooxygenase inhibitors

2-(Acetoxyphenyl)-(Z)-styryl sulfides are described as selective cyclooxygenase-2 (COX-2) inhibitors, useful for treating inflammation and COX-2-mediated disorders including neoplasia. 2-(Acetoxyphenyl)-(Z)-styryl sulfide is claimed to be the most potent COX inhibitor in the series with a COX-2 selectivity ratio of 33. This compound is also claimed to be superior to celecoxib (Celebrex^®, Pfizer) in inhibiting cell growth of colorectal carcinoma cells. In this evaluation, the COX inhibitory activity of this compound is compared to that previously disclosed for diarylheterocycles and 2-(acetoxyphenyl)alkyl sulfides. The validity of the DLD-1 cell line in the growth inhibition studies is questioned based on recent literature reports indicating the lack of COX-2 expression in this cell line.     

Sleep-disordered breathing with chronic opioid use

Chronic opioid use for pain relief or as substitution therapy for illicit drug abuse is prevalent in our societies. In the US, retail distribution of methadone and oxycodone has increased by 824 and 660%, respectively, between 1997 and 2003. μ-Opioids depress respiration and deaths related to illicit and non illicit chronic opioid use are not uncommon. Since 2001 there has been an emerging literature that suggests that chronic opioid use is related to central sleep apnoea of both periodic and non-periodic breathing types, and occurs in ～ 30% of these subjects. The clinical significance of these sleep-related abnormalities are unknown. This review addresses the present knowledge of control of ventilation mechanisms during wakefulness and sleep, the effects of opioids on ventilatory control mechanisms, the sleep-disordered breathing found with chronic opioid use and a discussion regarding the future research directions in this area.     

Drug targets for cognitive enhancement in neuropsychiatric disorders

The investigation of novel drug targets for treating cognitive impairments associated with neurological and psychiatric disorders remains a primary focus of study in central nervous system (CNS) research. Many promising new therapies are progressing through preclinical and clinical development, and offer the potential of improved treatment options for neurodegenerative diseases such as Alzheimer's disease (AD) as well as other disorders that have not been particularly well treated to date like the cognitive impairments associated with schizophrenia (CIAS). Among targets under investigation, cholinergic receptors have received much attention with several nicotinic agonists (α7 and α4β2) actively in clinical trials for the treatment of AD, CIAS and attention deficit hyperactivity disorder (ADHD). Both glutamatergic and serotonergic (5-HT) agonists and antagonists have profound effects on neurotransmission and improve cognitive function in preclinical experiments with animals; some of these compounds are now in proof-of-concept studies in humans. Several histamine H3 receptor antagonists are in clinical development not only for cognitive enhancement, but also for the treatment of narcolepsy and cognitive deficits due to sleep deprivation because of their expression in brain sleep centers. Compounds that dampen inhibitory tone (e.g., GABA_A α5 inverse agonists) or elevate excitatory tone (e.g., glycine transporter inhibitors) offer novel approaches for treating diseases such as schizophrenia, AD and Down syndrome. In addition to cell surface receptors, intracellular drug targets such as the phosphodiesterases (PDEs) are known to impact signaling pathways that affect long-term memory formation and working memory. Overall, there is a genuine need to treat cognitive deficits associated with many neuropsychiatric conditions as well as an increasingly aging population.