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1.
间硝苯地平(m-Nif,ig20mg·kg-1·d1持续给药9周)可显著降低老龄肾性高血压大鼠(RVHR)血压和左室重量(P<0.01),增高心、脑微粒体Na+,K+-ATP酶和Ca2+-ATP酶活性(P<0.01),降低Mg2+-ATP酶活性,体外量效关系研究发现,m-Nif在较高剂量(10~1000μmol·L-1)时可增高RVHR心脑微粒体Na+,K+-ATP酶和Ca2+-ATP酶活性,且随剂量增加而增高。上述结果表明,m-Nif可改善老龄RVHR心脑微粒体Na+,K+泵和Ca2+泵功能。  相似文献   

2.
大鼠蛛网膜下腔注射强啡肽A(1-17),观察其所引起的行为变化及对脊髓组织AC-cAMP系统的影响。强啡肽A(1-17)5、10、20nmol可引起大鼠双后肢弛缓性瘫痪,并在给药10min强啡肽A(1-17)10、20nmol显著抑制脊髓组织cAMP含量和AC活性,呈量效关系,2h后均有不同程度的恢复。选择性k型阿片受体拮抗剂nor-BNI30nmol可明显对抗强啡肽A(1-17)20nmol所致的后肢瘫痪并完全阻断其对AC、cAMP的抑制作用;L型Ca2+通道阻断剂异搏定100nmol亦可部分阻断强啡肽A(1-17)对脊髓的影响;而兴奋性氨基酸NMDA受体特异性拮抗剂APV10nmol则无效。提示k型阿片受体和L型Ca2+通道参与了强啡肽A(1-17)所引起的大鼠运动障碍及对脊髓组织AC、cAMP水平的调控。  相似文献   

3.
用氚胸腺嘧啶核苷(3HTdR)掺入法,电镜,免疫组化,原位杂交方法,在自发性高血压大鼠(SHR)观察了1(2,6二甲基苯氧基)2(3,4二甲氧基苯乙胺基)丙烷盐酸盐(DDPH)对血管平滑肌细胞(VSMC)增殖的作用及对生长因子PDGFB,bFGF及其相关癌基因csis与cmyc表达的影响。结果发现:DDPH在降低SHR血压同时,能减少肾动脉VSMC的线粒体,粗面内质网和3HTdR掺入量,并能逆转VSMC增殖时PDGFB,bFGF抗原及csis与cmycmRNA的表达增强。提示:DDPH能抑制SHR的VSMC增殖,与生长因子及癌基因调控的分子生物学机制有关。  相似文献   

4.
目的:研究精氨加压素(4-8)(AVP(4-8)对大鼠脑内促细胞分裂素活化的蛋白激酶(MAPK)活性变化的影响,方法:大鼠皮下注射AVP(4-8)后,通过柱分离后测定脑组织匀浆液中,MAPK对其特异性底物髓脂碱性蛋白(MBP)的磷酸化活性。结果:AVP(4-8)刺激的大鼠海马和大脑皮层中的44kDaMAPK活性显著增高,这种活性增高被AVP(4-8)的拮抗剂ZDC(C)PR降低80%,MAPK蛋白  相似文献   

5.
观察强啡肽A(1-17)经大鼠蛛网膜下腔注射后对胞内Ca2+受体钙调蛋白(CaM)含量及其依赖于Ca2+/CaM的磷酸二酯酶(PDE)活性的影响。结果表明:强啡肽A(1-17)10、20nmol给药10min可使脊髓组织CaM含量和PDE活性明显下降,呈量效依赖关系,2h后均有不同程度的恢复。选择性k型阿片受体拮抗剂nor-BNI30nmol、兴奋性氨基酸NMDA受体特异性拮抗剂APV10nmol可显著对抗强啡肽A(1-17)20nmol降低脊髓组织CaM含量的作用并完全阻断强啡肽A(1-17)对PDE活性的抑制;L型Ca2+通道阻断剂异搏定100nmol亦可部分阻断强啡肽A(1-17)20nmol对脊髓组织CaM含量和PDE活性的影响。  相似文献   

6.
目的:研究K+去极化对大鼠纹状体突触体酪氨酸3单加氧酶(TM)激活的机制及SPD对此激活的影响.方法:应用HPLCECD法测定DOPA为TM的活性,并应用同位素法测定PKⅡ和PKC的活性.结果:SPD1,10和100μmol·L-1增强K+去极化对突触体TM的活性,PKC抑制剂PMB10μmol·L-1能完全逆转K+去极化的激活效应,而选择性D2受体激动剂QP,CaM拮抗剂W7和去除反应液中的Ca2+均不影响K+去极化对TM的激活.K+去极化使突触体PKC的活性增加53%,而对PKⅡ的活性无影响.SPD和QP均不影响K+去极化对PKC的激活.结论:K+去极化对突触体TM的激活作用是由PKC介导的,不受突触前DA自身受体的调控,但被SPD增强.  相似文献   

7.
(Sp)-8-氯腺苷-3',5'-环磷酸辛酯(Sp-octyl8-chloroadenosine3',5'-cyclophosphate,OCC)对人白血病HL-60细胞有生长抑制和分化诱导作用,该作用与OCC浓度和处理时间呈正相关,为不可逆性。流式细胞光度术发现,OCC阻断HL-60细胞周期于G1期。参入实验证实,OCC对HL-60细胞DNA合成有显著抑制作用,但不影响RNA和蛋白质合成。OCC能直接激活HL-60细胞浆中提取的蛋白激酶A(PKA),并抑制它与cAMP的结合。经OCC处理的HL-60细胞浆中PKA活性明显升高,说明OCC能与cAMP竞争PKA的结合并激活PKA。  相似文献   

8.
用[3H]胸腺嘧啶核苷([3H]TdR)参入法,电镜,免疫组化,原位杂交方法,在自发性高血压大鼠(SHR)观察了粉防己碱(Tet,0.03μmol·kg-1·d-1×8周ig)对血管平滑肌细胞(VSMC)增殖的作用及对生长因子PDGF-B,bFGF的抗原表达及其相关癌基因c-sis,c-mycmRNA表达的影响.结果发现:Tet在降低SHR血压(P<0.01)同时,能减少VSMC的线粒体,粗面内质网和[3H]TdR参入量(P<0.01),并能逆转VSMC增殖时PDGF-B,bFGF抗原(P<0.05)及c-sis,c-mycmRNA的表达增强.提示:Tet抑制SHR的VSMC增殖与生长因子及癌基因调控的分子生物学机制有关  相似文献   

9.
研究测定慢性肾功能衰竭家兔肾组织中ATP,ADP,AMP的含量。方法:用高效液相色谱法(HPLC),ULTRASPHERE(TM)C18柱(4.6mm×25cm),流动相为甲醇磷酸缓冲液(pH5.9,30mmol·L-1)(3∶97),检测波长254nm,在6min内检测完毕。结果:家兔肾组织中磷酸腺苷ATP,ADP,AMP)的含量分别为89.6±10.2,112.4±8.9,78.4±6.2μg·g-1(湿组织),平均回收率分别为100.9%,99.9%,101.0%。结论:此方法简便,快速,准确,可用于药物监测及基础研究。  相似文献   

10.
目的:检测过氧化氢(H2O2)、甲磺酸乙酯(EMS)、丝裂霉素C(MMC)、二甲基亚硝胺(DMNA)、苯并(a)芘(BaP)、2氨基芴(2AF)和环磷酰胺(CP)诱发小鼠、大鼠及人外周血淋巴细胞DNA单链断裂.方法:体外单细胞微量凝胶碱性电泳试验(慧星试验).结果:除EMS097mmol·L-1在小鼠淋巴细胞,MMC30μmol·L-1在小鼠、人淋巴细胞中呈阴性外,其余均为阳性.最低可检测浓度分别为H2O21μmol·L-1,EMS048mmol·L-1,BaP50μmol·L-1,CP20mmol·L-1,MMC10μmol·L-1,DMNA273mmol·L-1,2AF625μmol·L-1.CP、BaP、2AF需经S9Mix代谢活化才显示毒性.结论:彗星试验检测出MMC诱导大鼠,EMS诱导大鼠和人,以及H2O2、DMNA、BaP、CP和2AF诱导小鼠、大鼠和人外周血淋巴细胞DNA单链断裂损伤.  相似文献   

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12.
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.
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.
  相似文献   

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14.
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.  相似文献   

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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.  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

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