次黄嘌呤核苷酸脱氢酶抑制剂N01WB-352A、B的研究

目的筛选次黄嘌呤核苷酸脱氢酶（IMPDH）的抑制剂,为新的抗癌药物和免疫抑制剂研发提供先导化合物。方法利用IMPDH抑制剂的高通量筛选方法,筛选放线菌次级代谢产物,发现阳性菌株;对阳性菌株的发酵提取物进行分离纯化获得活性化合物并通过综合波谱解析确定其结构;然后利用多种相关细胞对活性化合物进行活性评价。结果筛选得到两个活性化合物N01WB-352A、B;它们对IMPDH的IC₅₀分别为6.01μmol/L和1.40μmol/L。在细胞毒活性测定中,它们对多种相关细胞的增殖有抑制作用,IC₅₀值如下:对一系列人源癌细胞在11.6～556nmol/L之间;对人脐静脉内皮细胞ECV--304分别为185nmol/1L,和147nmol/L:对小鼠T淋巴细胞分别为546nmol/L和425nmol/L。另外,它们对人正常胎肝细胞L02在100μmol/L浓度下未显示出增殖抑制。结论 N01WB-352A、B为特异性的IMPDH抑制剂,国内外未见报道。在细胞水平上的活性评价显示它们具有一定的开发成抗癌药物和免疫抑制药物的潜力。     

次黄嘌呤核苷酸脱氢酶抑制剂产生菌的筛选及aquayamycin的结构鉴定

筛选次黄嘌呤核苷酸脱氢酶(IMPDH)抑制剂及其产生菌,为新的抗癌药物和免疫抑制药物的研发提供先导化合物。对菌株进行发酵培养,通过以IMPDH为靶点的高通量筛选模型获得微生物活性代谢产物及其阳性菌种,采用16s rDNA序列构建阳性菌株的系统发育进化树,综合波谱解析确定化合物结构,并利用相关细胞对化合物进行活性评价。结果鉴定N05WA-1324A产生菌菌株为链霉菌属菌株,m/z 486,分子式为C₂₅H₂₆O₁₀,为aquayamycin。该化合物具有较强的IMPDH抑制活性,IC50为18.1μmol/L;对T淋巴细胞有很强的抑制活性,在2.5μmol/L浓度下能抑制99.8%的细胞增殖;同时对人结肠癌细胞株SW-620和人乳腺癌细胞株MDA-MB-231具有较强的增殖抑制活性,IC50分别为8.6和23.3μmol/L。N05WA-1324A具有很强的IMPDH和免疫抑制活性为国内外首次报道,在细胞水平上的活性评价显示其具有抗癌药物和免疫抑制药物的开发潜力。     

次黄嘌呤核苷酸脱氢酶抑制剂NO1WB-352A、B的研究

目的 筛选次黄嘌呤核苷酸脱氢酶(IMPDH)的抑制剂,为新的抗癌药物和免疫抑制剂研发提供先导化合物.方法利用IMPDH抑制剂的高通量筛选方法,筛选放线菌次级代谢产物,发现阳性菌株;对阳性菌株的发酵提取物进行分离纯化获得活性化合物并通过综合波谱解析确定其结构;然后利用多种相关细胞对活性化合物进行活性评价.结果 筛选得到两个活性化合物NO1WB-352A、B;它们对IMPDH的IC50分别为6.01 μmol/L和1.40μmol/L.在细胞毒活性测定中,它们对多种相关细胞的增殖有抑制作用,IC50值如下:对一系列人源癌细胞在11.6～556nmol/L之间;对人脐静脉内皮细胞ECV-304分别为185nmol/L和147nmol/L ;对小鼠T淋巴细胞分别为546nmol/L和425nmol/L.另外,它们对人正常胎肝细胞L02在100 μmol/L浓度下未显示出增殖抑制.结论 N01WB-352A、B为特异性的IMPDH抑制剂,国内外未见报道.在细胞水平上的活性评价显示它们具有一定的开发成抗癌药物和免疫抑制药物的潜力.     

褪黑素对淋巴细胞功能的影响

本文采用~3H-TdR掺入法和ConA活化脾细胞检测IL-2的方法观察了松果腺褪黑素(MT)对ConA和LPS诱导小鼠脾T_1,B淋巴细胞增殖反应及ConA诱导大鼠脾淋巴细胞产生IL-2的影响。结果表明,MT0.01～1μmol/L和0.01～10μmol/L分别促进ConA和LPS诱导小鼠脾淋巴细胞增殖反应,ATl～10μmol/L对ConA诱导大鼠脾淋巴细胞产生IL-2亦有促进作用,但MT对未经ConA或LPS活化的淋巴细胞功能则无明显影响,提示丝裂原活化的淋巴细胞可能是MT作用的靶细胞之     

穿心莲内酯3,19-缩醛（酮）衍生物对小鼠脾淋巴细胞增殖活性的影响*

目的:评价穿心莲内酯及其衍生物对小鼠脾淋巴细胞增殖活性的影响,用于指导以穿心莲内酯为先导化合物的新型免疫调节剂的合成。方法:采用MTT法,在1.56~12.50μmol.L-1定量考察穿心莲内酯及其3,19-缩醛(酮)衍生物对小鼠脾淋巴细胞增殖反应的影响。结果:穿心莲内酯对丝裂原诱导的淋巴细胞增殖活性有显著的抑制作用。通过半合成改造得到的3,19-缩醛(酮)衍生物可使抑制活性显著提高,但是部分衍生物在1.56~6.25μmol.L-1内表现出促进T或/和B淋巴细胞增殖的作用。结论:穿心莲内酯3,19-缩醛(酮)衍生物对穿心莲内酯作为开发免疫调节剂的先导化合物有重要价值和潜力。     

褪黑素对不同月龄小鼠免疫反应的影响及其机制

目的:研究褪黑素对不同月龄小鼠免疫反应的影响及其作用机制。方法:淋巴细胞增殖采用MTT法;IL-2活性检测 采用激活小鼠脾淋巴细胞增殖法;cAMP测定用竞争蛋白结合法;甲硫氨酸脑啡肽的测定采用放免法。结果:6月龄和11月龄BALB/c小鼠胸腺淋巴细胞增殖能力和IL-2的产生均降低,褪黑素(5mg/kg或30mg/kg,ig×7d)对上述指标有不同程度的改善作用,在体外,11月龄小鼠胸腺淋巴细胞增殖反应明显降低,而其产生的cAMP则明显升高,褪黑素(0.1nmol/L和1μmol/L)对此有反向调节作用,弗司可林(10μmol/L)(腺苷酸环化酶选择性激活剂)能够增强2月龄和11月龄BALB/c小鼠胸腺淋巴细胞内的cAMP水平,褪黑素可部分拮抗此作用,褪黑素的这一作用可被百日咳毒素(1mg/L)完全取消,同时发现褪黑素(1μmol/L和0.1nmol/L)能够明显提高2月龄和11月龄BALB/c小鼠胸腺淋巴细胞的甲硫氨酸脑啡肽含量,这一作用能被硝苯地平(1μmol/L)所阻断,提示褪黑素促进淋巴细胞甲硫氨酸脑啡肽释放可能由Ca~(2+)通道介导。结论:褪黑素对不同月龄小鼠具有免疫调节作用;G蛋白偶联的AC-cAMP信号转导通路和淋巴细胞甲硫氨酸脑啡肽的释放可能是褪黑素发挥免疫调节作用的重要机制之一。     

一株海洋放线菌次级代谢产物抗真菌活性的研究

随着真菌感染的发病率及抗药性的逐年上升,筛选新的抗真菌活性物质已成为临床治疗系统性真菌感染的迫切需要。以双层琼脂扩散法测定抗真菌活性,研究10株海洋放线菌的发酵液及其菌体甲醇提取液对白色念珠菌的抑制作用。结果筛选到一株胞内含有抗真菌活性物质的海洋放线菌Actinomycete A9,经10 L发酵罐发酵,将菌体甲醇提取物及发酵液乙酸乙酯萃取液浓缩合并,利用硅胶柱层析、葡聚糖凝胶柱层析Sephadex LH-20等分离纯化手段,最终获得1 mg浅黄色针状晶体的单一化合物,纯度为99.9%。同时,以ConA、LPS诱导的小鼠脾淋巴细胞增殖为模型,发现Actinomycete A9经硅胶柱层析分离后的抗真菌组分(10μg/mL)能够抑制ConA、LPS诱导的小鼠脾淋巴细胞增殖,表明海洋放线菌Actinomycete A9的胞内活性物质具有抗真菌及免疫抑制活性,为后续研究奠定了基础。     

海洋来源链霉菌FIM090041产生的神经氨酸酶抑制剂

目的筛选神经氨酸酶抑制剂,发现潜在的抗流感药物先导化合物。方法利用神经氨酸酶抑制剂高通量筛选方法,从海洋微生物菌库中筛选产生神经氨酸酶抑制剂的菌株,采用多种色谱技术分离纯化获得活性化合物,通过紫外、质谱、核磁共振等现代波谱学方法鉴定其结构。结果分离到两个吲哚生物碱类活性化合物1和化合物2,结构解析确定它们分别与SF2583 A和SF2583 B同质,对神经氨酸酶的IC50为67.8μmol/L和122.8μmol/L,Ki为13.5μmol/L和21.6μmol/L。结论本文首次报道该化学结构类型化合物对神经氨酸酶具有一定的抑制作用。     

辛伐他汀联合顺铂对人非小细胞肺癌A549细胞增殖的抑制作用

目的研究辛伐他汀联合顺铂对人非小细胞肺癌A549细胞的抑制作用,并探讨其作用机制。方法采用MTT法检测0.625、1.25、2.5、5、10μmol/L顺铂和3.125、6.25、12.5、25、50μmol/L辛伐他汀对A549细胞增殖抑制率的影响;考察2.5μmol/L顺铂与3.125、6.25、12.5、25、50μmol/L辛伐他汀联用对A549细胞增殖抑制作用的协同效果;Annexin V-FITC/PI双染后流式细胞术检测5μmol/L顺铂与25μmol/L辛伐他汀联合应用对对A549细胞凋亡率的影响;分光光度法检测辛伐他汀(25μmol/L)联合顺铂(2.5μmol/L)对A549细胞caspase-3活性的影响。结果辛伐他汀或顺铂对A549细胞的增殖有显著的抑制作用,随着浓度的增加、时间的延长,呈时间、剂量相关性,其抑制作用增强(P0.01)。顺铂(2.5μmol/L)与不同浓度(3.125、6.25、12.5、25、50μmol/L)辛伐他汀联用对A549细胞的增殖有抑制作用,随着时间的延长,辛伐他汀剂量的增加,两者联用抑制作用呈增强的趋势(P0.01),2.5μmol/L顺铂联用辛伐他汀25μmol/L的抑制作用具有协同效果。25μmol/L辛伐他汀和2.5μmol/L顺铂能有效地诱导A549细胞的凋亡,而且两者联合使用可以显著增加A549细胞的凋亡率。25μmol/L辛伐他汀联合2.5μmol/L顺铂应可以显著增加A549细胞的caspase-3酶活性。结论辛伐他汀能够显著增强顺铂对A549细胞增殖抑制、诱导凋亡的作用,可能通过上调caspase-3活性诱导A549细胞凋亡。     

白芷提取物对大鼠脾淋巴细胞免疫抑制作用初探

目的探讨白芷提取物对地塞米松致大鼠脾淋巴细胞免疫抑制作用的影响。方法建立地塞米松致大鼠免疫抑制模型,考察白芷提取物对大鼠脾淋巴细胞的增殖活性、自然杀伤细胞（NK细胞）活性的影响。结果白芷提取物（5．0g/kg）对刀豆蛋白A（ConA）诱导脾淋巴T细胞增殖能力有升高作用,但对脂多糖（LPS）诱导脾淋巴B细胞增殖能力未见明显影响,对脾淋巴细胞的NK细胞活性也有增强作用。结论白芷提取物（5．0g／kg）曲能提高大鼠脾淋巴T细胞和NK细胞的增殖活性。     

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.