叶酸抑制同型半胱氨酸诱导大鼠血管平滑肌细胞增殖的研究

目的探讨叶酸抑制同型半胱氨酸致大鼠血管平滑肌细胞增殖的研究。方法培养大鼠胸主动脉血管平滑肌细胞(VSMC),流式细胞仪检测VSMC周期,[3H]TdR参入测定VSMC的DNA合成。结果同型半胱氨酸以剂量依赖关系使VSMC周期中的G0/G1期细胞比例明显减少,S期细胞比例显著增多,增加VSMC的[3H]TdR参入。叶酸可明显抑制同型半胱氨酸诱导的作用。结论同型半胱氨酸能诱导VSMC增殖,叶酸能抑制同型半胱氨酸诱导的VSMC增殖。     

叶酸抑制同型半胱氨酸诱导大鼠血管平滑肌细胞增殖的研究

目的探讨叶酸抑制同型半胱氨酸致大鼠血管平滑肌细胞增殖的研究。方法培养大鼠胸主动脉血管平滑肌细胞(VSMC),流式细胞仪检测VSMC周期,[³H]TdR参入测定VSMC的DNA合成。结果同型半胱氨酸以剂量依赖关系使VSMC周期中的G₀/G₁期细胞比例明显减少,S期细胞比例显著增多,增加VSMC的[³H]TdR参入。叶酸可明显抑制同型半胱氨酸诱导的作用。结论同型半胱氨酸能诱导VSMC增殖,叶酸能抑制同型半胱氨酸诱导的VSMC增殖。     

虎杖苷对VSMC内钙信号的调节机制初探

目的　观察虎杖苷对大鼠主动脉平滑肌细胞(VSMC)内游离钙浓度的变化 ,以探讨虎杖苷对血管平滑肌细胞的调节机制。方法　用荧光染料Fluo 3 AM标记细胞 ,在粘附式细胞仪上测定细胞内游离钙的变化。结果　给予虎杖苷 5min后 ,VSMC内游离钙浓度升高。当虎杖苷加入前 10min用河豚毒素和优降糖分别预处理后 ,其VSMC内游离钙都不再明显升高 ;而给予普萘洛尔、甲氰咪胍及亚甲蓝分别预处理时 ,细胞内钙浓度反而升得更高 ,与单纯虎杖苷作用相比差异都有显著性。结论　虎杖苷可增加细胞内游离钙浓度 ,其作用可能与钠、钾通道开放有关 ,并且受 β肾上腺素能受体、H2 受体系统及鸟苷酸环化酶系统的反向调节。     

大黄酸抑制转化生长因子β1诱导的肾小管上皮细胞肥大及细胞外基质积聚

目的：观察大黄酸对TGFβ1诱导的肾近端小管上皮细胞肥大及细胞外基质的影响。方法：在体外以TGFβ1（2μg/L）刺激LLC－PK1细胞,诱导细胞肥大和细胞外基质合成的增加。同时,以不同浓度的大黄酸处理细胞,检测细胞体积、蛋白质含量以及[^3H]亮氨酸掺入以观察细胞肥大的变化。此外,检测细胞培养上清液中的纤维素增生（FN）含量。[^3H]脯氨酸掺入以及细胞胶原IV及FN mRNA的表达以观察大黄酸对细胞外基质的影响。结果：TGFβ1（2μg/L）刺激可以导致LLC－PK1细胞出现细胞肥大,表现为细胞体积、细胞内蛋白量及[^3H]亮氨酸掺入量明显增加,大黄酸治疗后细胞体积及细胞内蛋白量降低。TGFβ1也能明显增加LLC－PK1细胞[^3H]脯氨酸掺入量,培养上清液中FN含量,以及细胞内胶原IV和FN mRNA的表达。大黄酸则能抑制上述细胞外基质合成的影响,明显降低细胞内胶原IV和FN mRNA表达水平。结论：大黄酸可以逆转TGFβ1诱导的近端肾小管上皮细胞肥大,抑制TGFβ1刺激的细胞外基质合成,这可能是大黄酸预防或改善糖尿病肾脏病变、延缓糖尿病肾病进展的作用机制之一。     

血小板源生生长因子刺激血管平滑肌细胞增殖及其分子机制

目的：探讨血小板源生生长因子（PDGF－BB）刺激血管平滑肌细胞（VSMC）增殖及其分子机制。方法：用Western Blot法测定p44/p42 CCDPK活性。[^3H]脱氧胸腺嘧啶核苷酸掺入测定VSMC DNA合成。原位杂交检测c-myc mRNA的表达。结果：PDGFBB诱导的磷酸化CCDPK蛋白表达和[^3H]脱氧胸腺嘧啶核苷酸掺入呈浓度依赖性,此作用可被PTK抑制剂Genistein,外钙络合剂依他酸和MEK抑制剂PD 98059抑制。PDGF－BB刺激可引起c-myc mRNA的明显表达,此作用可被PD 98059抑制。结论：PDGF－BB通过激活p44/p42 CCDPK,上调c-myc mRNA的表达从而促进VSMC增殖,其作用是由PTK和Ca^2 介导的。     

15-HETE对肺动脉平滑肌细胞钙离子浓度的影响

目的　通过阻断细胞外钙离子 (Ca2+ )内流,观察 15 羟化二十烷四烯酸 ( 15 HETE)对兔肺动脉环收缩张力和肺动脉平滑肌细胞内游离钙浓度 ( [Ca2+ ]i)的影响,探讨缺氧时 15 HETE引起细胞钙动员的机制。方法　采用组织浴槽血管环方法观察L 型钙通道阻断剂硝苯地平和无钙液对15 HETE诱导的兔肺动脉环收缩力的影响;酶法分离培养兔肺动脉平滑肌细胞,激光扫描共聚焦显微镜测定 15 HETE对细胞内 [Ca2+ ]i的作用。结果　在正常组和缺氧组, 10μmol·L-1硝苯地平和无钙液对 1μmol·L-1 15 HETE引起的肺动脉环收缩均没有影响;培养的 15 HETE组细胞 (正常培养的细胞暴露于 1 μmol·L-1 15 HETE下继续孵育 8min)与正常对照组相比,细胞内 [Ca2+ ]i明显增加 (P<0 05)。结论　15 HETE可引起肺动脉平滑肌细胞 [Ca2+ ]i增加,且此钙来源于细胞内贮钙库的释放。     

黄芪抑制血管平滑肌细胞增殖及其作用机制

目的 观察黄芪(AS)对血管平滑肌细胞(VSMC)增殖的抑制作用，了解黄芪是否通过刺激VSMC产生一氧化氮(nitric oxide，NO)，使细胞周期停滞于G0／G1期，从而抑制平滑肌细胞增殖。方法 [3H]-胸腺嘧啶核苷酸([3H]-TdR)掺入测定VSMCDNA合成，流式细胞仪检测细胞周期情况，硝酸还原酶法测定细胞培养上清中NO水平。结果 黄芪以剂量依赖关系抑制血清诱导的VSMC[3H]-胸腺嘧啶核苷酸掺入，使G0／G1期细胞比例明显增多，S期细胞比例显著减少，黄芪刺激VSMC后，细胞培养上清中NO水平呈剂量依赖上升。结论黄芪能抑制VSMC增殖，使细胞周期停滞于G0／G1期，这一过程可能与黄芪刺激VSMC产生NO有关。     

SB_(224289)对5-HT诱导的肺动脉平滑肌细胞增殖的影响

目的研究 5 HT1B受体拮抗剂SB2 2 42 89对 5 HT诱导的肺动脉平滑肌细胞增殖的影响 ,探讨肺血管构型重建的 5 HT1B受体机制。方法分离培养大鼠肺动脉平滑肌细胞 ,用MTT法和3 H TdR掺入法检测细胞增殖和DNA合成。结果SB2 2 42 89能剂量依赖地抑制 5 HT诱导的肺动脉平滑肌细胞增殖。SB2 2 42 89能剂量依赖地抑制 5 HT诱导的肺动脉平滑肌细胞的DNA合成 ,SB2 2 42 89能阻断 5 HT对肺动脉平滑肌细胞的促有丝分裂作用。结论SB2 2 42 89能抑制 5 HT引起的肺动脉平滑肌细胞的增殖。5 HT1B受体在 5 HT诱导的肺动脉平滑肌细胞增殖中有重要作用。     

血管紧张素转化酶和血管紧张素Ⅱ对低氧促培养的肺内小动脉平滑肌细胞增殖作用的影响

目的：研究局部血管紧张素转化酶及血管紧张素Ⅱ和低氧促进肺动脉平滑肌细胞增殖作用之间的关系。方法：分离培养肺内小动脉平滑肌细胞,测定[^3H]thymidine掺入和细胞计数作为细胞增殖的指标。结果：低氧显著促进培养的肺内小动脉平滑肌细胞增殖,其[^3H]thymidine掺入和细胞计数分别增加166．6％（P＜0．01）和52．0％（P＜0．01）。captopril和losartan预处理可显著抑制低氧对肺内小动脉平滑肌细胞增殖的促进作用,[^3H]thymidine掺入分别被抑制51．3％（P＜0．01）和49．8％（P＜0．01）,细胞计数分别被抑制22．2％（P＜0．01）和17．％（P＜0．01）。而PD－123319基本无明显作用。结论：肺内小动脉平滑肌细胞局部血管紧张素转化酶的过度表达及血管紧张素Ⅱ在低氧促平滑肌细胞增殖中发挥重要作用。     

粉防己碱抑制血管平滑肌细胞胶原合成

目的　观察粉防己碱(Tet)对血管壁胶原沉积和血管平滑肌细胞胶原蛋白合成的影响。方法　用羟脯氨酸含量反映主动脉胶原沉积状况,用[³H]-脯氨酸参入反映细胞胶原蛋白合成。结果　与伪手术组相比,肾血管性高血压大鼠主动脉壁羟脯氨酸含量明显增加;粉防己碱可有效降低主动脉壁胶原含量,并呈浓度依赖性抑制[³H]-脯氨酸参入AngII或NE诱导的血管平滑肌细胞。结论　粉防己碱抑制血管平滑肌细胞胶原合成和动脉壁胶原沉积是其逆转血管重构作用的重要机制之一     

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.     

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.