Cellular and Molecular Mechanisms of Action of Transcranial Direct Current Stimulation: Evidence from In Vitro and In Vivo Models

Transcranial direct current stimulation is a noninvasive technique that has been experimentally tested for a number of psychiatric and neurological conditions. Preliminary observations suggest that this approach can indeed influence a number of cellular and molecular pathways that may be disease relevant. However, the mechanisms of action underlying its beneficial effects are largely unknown and need to be better understood to allow this therapy to be used optimally. In this review, we summarize the physiological responses observed in vitro and in vivo, with a particular emphasis on cellular and molecular cascades associated with inflammation, angiogenesis, neurogenesis, and neuroplasticity recruited by direct current stimulation, a topic that has been largely neglected in the literature. A better understanding of the neural responses to transcranial direct current stimulation is critical if this therapy is to be used in large-scale clinical trials with a view of being routinely offered to patients suffering from various conditions affecting the central nervous system.     

清喉口含片动物体内、外抑菌实验研究

目的研究清喉口含片的体内、外抑菌作用。方法采用标准试管二倍稀释法测定清喉口含片的最低抑菌浓度(MIC)和最低杀菌浓度(MBC),并观察清喉口含片在小鼠体内对金黄色葡萄球菌的抑菌作用。结果清喉口含片对金黄色葡萄球菌、甲型溶血性链球菌、乙型溶血性链球菌、肺炎链球菌、流感嗜血杆菌均有明显的体外抑制作用,其MIC、MBC分别为0.0625~0.50、0.125~1.0g/ml,对腹腔注射金黄色葡萄球菌的小鼠具有抑菌作用。结论清喉口含片具有体内、外抑菌作用。     

Lack of In Vivo/In Vitro Correlations for 50 mg and 250 mg Primidone Tablets

Purpose. To determine if large differences in the in vitro dissolution profiles for primidone tablets would result in significant bioavailability differences. Methods. Two separate bioavailability studies were conducted. The first study used 18 healthy subjects and compared the bioavailability of an old 50 mg tablet formulation, a new 50 mg tablet formulation, and a suspension containing 50 mg/ml of primidone. The second study enrolled 24 subjects who were to receive a new 250 mg tablet formulation, two lots of an old 250 mg tablet formulation and a 250 mg tablet from a second manufacturer. In vitro dissolution was conducted over 90 minutes, using USP 23 Apparatus 2 at 50 rpm, with 900 ml of water. Results. Dissolution at 90 minutes for the old and new 50 mg tablets was approximately 20% and 100%, respectively. The dissolution of the four 250 mg tablets ranged from approximately 30% to 100%. The 50 mg tablet that dissolved slower had a longer Tmax and a 14% lower Cmax than the more rapidly dissolving tablet, but the AUC(0–) values differed by only 3%. Only nine subjects completed the 250 mg study because of side effects. The differences in Cmax and AUC(0–) among the four 250 mg tablets were less than 7%. Conclusions. Even though there were large differences in the in vitro dissolution of the 50 mg and the 250 mg primidone tablets, the two 50 mg tablets were shown to be bioequivalent, as were the four 250 mg tablets.     

Comparison of the AMPA Antagonist Action of New 2,3-Benzodiazepines in Vitro and Their Neuroprotective Effects in Vivo

PURPOSE: AMPA receptor-mediated excitotoxicity is thought to be a critical process in diseases accompanied by neuronal cell loss following a hypoxic/anoxic state of the central nervous system. It has been suggested that blockade of AMPA receptors might result in significant protection of neurons against cellular damage. For testing the hypothesis, in vitro efficacy and in vivo neuroprotective action of new 2,3-benzodiazepine (2,3BDZ) AMPA antagonists have been compared. METHODS: 2.3BDZs were tested on kainate-evoked whole-cell currents in cultured neurons as well as on population spikes (PS) in rat hippocampal slices. Data were correlated with those obtained from the spreading depression (SD) experiments in chicken retina. Compounds were also examined in the gerbil bilateral carotid occlusion model (BCO), where percentage decrease of ischemia-related hypermotility (HM), impaired spatial memory (SA), and hypoxia-induced hippocampal CA1 neuronal cell death (CA1) were evaluated. RESULTS: Certain structural modifications of classical 2,3BDZs resulted in increased in vitro activity and improved in vivo efficacy. In particular, the halogen-substituted compounds EGIS-9879 and EGIS-9883 showed the highest neuroprotective efficacy (84% and 47% protection in CA1, 71% and 82% decrease in HM, respectively; 4 x 5 mg/kg i.p.) in BCO. PS and SD were correlated to the decrease of neuronal loss in the CA1 area. Lack of significant correlation was found between PS and CA1 (r = 0.437, p = 0.079) or SD and CA1 (r = 0.380, p = 0.146). CONCLUSIONS: Several new 2.3BDZ AMPA receptor antagonists have been synthesized at EGIS Pharmaceuticals characterized by remarkable in vitro and corresponding in vivo neuroprotective properties.     

Immunotoxicological Study of One of the Most Common Over-The-Counter Pyrethroid Insecticide Products in Egypt

A commonly available aerosolized pyrethroid insecticide containing deltamethrin and imiprothrin is widely used for hygienic control in Egypt. The immunotoxic effects after inhalation exposures to the preparation of each for 2, 10, and 30 days were investigated in rats. For each exposure, the insecticide (containing 0.2% imiprothrin and 2.5% deltamethrin) was sprayed in all directions in a room (using a special attachment located in the ceiling in the center of the room) for 30 s each minute for 15 min; the room was then kept closed for 15 min. After each spray interval, the rats were introduced for 30 min and then removed to a clean room. The exposure process was repeated a total of three times on each day of the respective regimens. The interval between the 15-min spray/15-min pause/30-min rat exposure cycles was 120 min. Twenty-four hours after the final exposure in each particular regimen, the cohort rats in the regimen (air and exposed) were weighed, sacrificed, and their tissues were removed for analyses. Immunological tests performed included assessments of potential changes in immunopathology (determined from body and splenic weights), humoral-mediated immunity (based on plaque-forming activity of spleen cells), cell-mediated immunity (determined from splenic lymphocyte responsiveness to stimulation with phytohemagglutinin and immune cell (sub)type profile analyses), and nonspecific immunity (based on phagocytic activity of peritoneal macrophages). The results indicated that of all the endpoints examined, among the rats exposed over a 2-day period to the imiprothrin- and deltamethrin-containing insecticide aerosol, the only significant change noted (relative to values from time-matched controls) was in the levels of splenic CD4⁺CD8^? and CD4⁺ CD8⁺ cells. In contrast, exposures on each day of a 10-day period led to significant decreases in several endpoints; exceptions to this were values for body and spleen weight (unaffected), splenic OX12^?OX19⁺ levels (significant increase), and CD4⁺CD8^? levels (unaffected, relative to control). Rats exposed for 30 days displayed significant decreases in each test applied, except for increases in both splenic OX12^?OX19⁺ and CD4⁺CD8^? cell levels relative to corresponding control rat values. The present study findings indicate that repeated noncontinuous inhalation of a commonly utilized insecticide that contains imiprothrin and deltamethrin can cause a variety of immunotoxic effects in sites distal to the lungs.     

盐酸环丙沙星缓释片的体外释放与体内吸收的相关性

目的对盐酸环丙沙星缓释片体外释放与体内吸收的相关性进行研究。方法体外释放采用中国药典2000年版二部的转篮法,体内血药浓度以RP-HPLC法测定,以DAS软件计算药动学参数。结果在12h平均累积释放99%,20例男性健康志愿者口服单剂量500mg盐酸环丙沙星缓释片的体内过程符合开放一室模型。结论将体外释放百分率即释放度(F)对体内吸收分数(f)回归得回归方程为:f=-0.51853 1.14322F,对相关系数进行检验,两者之间存在显著相关性(P<0.05)。     

Lack of Correlation between para-Aminophenol Toxicity in Vivo and in Vitro in Female Sprague--Dawley Rats

The present study was designed to test the hypothesis that para-aminophenol(PAP) nephrotoxicity is due to autooxidation. We compared renalfunctional responses following PAP administration to femaleSprague-Dawley rats and following incubation of renal proximaltubules with PAP. The concentrations of PAP selected for invitro incubations produced cytotoxicity (for example, a decreasein oxygen consumption or adenine nucleotide concentration) inrat renal epithelial cells or rabbit proximal tubule suspensions.In rats, PAP (300 mg/kg ip) caused proximal tubular necrosiswithin 24 hr. Changes in renal function 24 hr following PAPadministration included increased kidney weight and blood ureanitrogen concentration and decreased renal glutathione (GSH)content and adenine nucleotide concentrations. PAP did not causehepatic damage. Within 2–4 hr following PAP administration,renal GSH content and adenine nucleotide concentrations weresignificantly decreased. In renal cortical slices prepared fromPAP-treated rats, oxygen consumption and accumulation of organicions (para-aminohippurate and tetraethylammonium) were significantlydecreased compared with renal cortical slices prepared fromcontrol rats. In liver, GSH content was significantly decreasedfrom 1 to 4 hr following PAP administration. In contrast tothe effects of PAP in vivo, renal proximal tubules showed littleevidence of injury when incubated with 0.1 or 0.5 mM PAP forup to 4 hr in the presence or absence of amino acids in theincubation medium. When tubules were incubated with 1 mM PAPfor 4 hr in the presence of amino acids, GSH content, AMP concentration,and TEA uptake were significantly decreased. When amino acidswere removed from the incubation medium, 1 mM PAP caused decreasesin oxygen consumption and ATP concentration after 4 hr of incubation.Functional changes observed during incubation with PAP in vitrowere not consistent with functional changes observed in vivo.The discrepancy between PAP toxicity in vivo and in vitro suggeststhat autooxidation is unlikely to be responsible for PAP nephrotoxicityand that nephrotoxicity in vivo is primarily mediated by extrarenalbioactivation. Further, depletion of hepatic GSH content priorto changes in renal function suggests that PAP or a PAP metabolitemay conjugate with hepatic GSH. These observations suggest thatPAP nephrotoxicity may be mediated by PAP-GSH conjugates ratherthan autooxidation of PAP in the kidney.     

爱宁的致突变作用研究

目的检测爱宁的致突变性,以提供有关致突变的遗传毒性安全评价数据。方法设1.6,8,40,200和1000μg/皿5个剂量组,进行Am es试验;设0.3,1,3和9μg.mL-14个剂量组,进行仓鼠肺成纤维细胞染色体畸变试验;设15,100和250 mg.kg-13个剂量组,观察其对小鼠骨髓细胞微核的影响。结果Am es试验表明,爱宁在加和不加S9的条件下,对TA97,TA98,TA100和TA102菌株回复突变菌落结果为阴性。仓鼠肺成纤维细胞染色体畸变试验表明,爱宁对中国仓鼠肺成纤维细胞体外培养染色体无畸变作用。小鼠骨髓细胞微核试验表明,爱宁三个剂量组的微核出现率与阴性对照组比较无显著性差异。结论在本实验条件下,爱宁无致突变性。     

石杉碱甲缓释微球的体外释放度及其体内外相关性研究

目的建立体内外相关性良好的石杉碱甲缓释微球的体外释放度测定方法。方法采用直接释药法和透析释药法测定石杉碱甲缓释微球的体外释放度，考察加入吐温的量和透析袋内递质的体积对释药速度的影响;采用高效液相色谱法测定石杉碱甲缓释微球在大鼠注射部位的残留量，计算微球在体内的释药速度。通过相关性评价确定最佳的体外释放度测定方法。结果透析释药法可获得良好的体内外相关性(r＝0.990 2)。结论透析释药法可用于测定石杉碱甲缓释微球的体外释放度。     

清开灵注射液抗内毒素作用的实验研究

目的探讨清开灵注射液抗大肠埃希菌O111B4内毒素作用。方法采用细菌内毒素检查法(体外)和兔热原检查法(体内)，对清开灵     

黄连解毒汤体内外抗肿瘤作用的实验研究

目的：观察黄连解毒汤的体内、体外抗肿瘤作用。 方法：采用小鼠肉瘤S180和小鼠前胃癌MFC等移植性肿瘤模型进行体内实验,通过检测抑瘤率、胸腺指数、脾脏指数等指标观察黄连解毒汤的体内抑瘤作用及对免疫器官的影响。并用MTT方法检测黄连解毒汤对小鼠S180、小鼠MFC、人胃癌SGC-7901、人肝癌SMMC-7721等4种瘤株的抑制作用。结果：黄连解毒汤大、中剂量组中对S180荷瘤小鼠有抑制作用,大剂量组对MFC荷瘤小鼠有抑制作用,抑瘤率分别为48.38%、33.77%、30.74%;对S180、MFC、SGC-7901和SMMC-7721细胞均有一定的细胞毒作用, IC50分别为99.73 mg?L-1、84.47 mg?L-1、153.32 mg?L-1和102.87 mg?L-1。结论：黄连解毒汤体内对S180、MFC小鼠移植瘤有一定的抗肿瘤活性,体外对4种肿瘤细胞也具有抑制作用。     

丹红注射液溶血机制的初步试验研究

目的 对丹红注射液体内外溶血及可能的机制进行试验研究.方法 按《中国药典》方法进行体外溶血试验;大鼠给药后取血测定FHb、LDH、红细胞数以及红细胞渗透脆性变化;家兔给药后,取血进行羊抗兔IgG凝集试验.结果 体外试验可见轻微溶血,显微镜下红细胞形状改变;大鼠给药后5h,血液LDH降低,红细胞渗透脆性升高,FHb含量未见明显变化;家兔连续给药8d,红细胞加羊抗兔IgG未见凝集反应.结论 药物体内外溶血试验未见明显溶血;未发现免疫性溶血.     

头孢地嗪钠体内、外抗菌活性研究

目的:评价国产及进口头孢地嗪钠(CDZ)体内、外抗菌活性。方法:采用琼脂平皿稀释法及试管稀释法测定国产CDZ及其进口制剂、头孢氨噻肟钠对300株临床分离致病菌的最低抑菌浓度( MIC) ;采用小鼠腹腔感染模型,观察CDZ对大肠杆菌、克雷伯氏肺炎杆菌及金黄色葡萄球菌感染小鼠的体内抗菌作用,按Bliss法计算半数有效剂量(ED50)值。结果:国产和进口CDZ对大部分革兰阴性菌,革兰阳性菌中的肺炎球菌、乙型链球菌等具有显著的抗菌活性,MIC90大多为0.012～1.0μg·mL-1。对阴沟杆菌、产气杆菌和沙雷氏菌具有中度抗菌活性,对甲氧西林敏感金黄色葡萄球菌、表皮葡萄球菌抗菌活性较差,MIC50为4μg·mL-1。对本实验所试绿脓杆菌、不动杆菌、肠球菌、甲氧西林耐药金黄色葡萄球菌耐药。对敏感大肠杆菌、克雷伯氏肺炎杆菌及金黄色葡萄球菌感染模型小鼠均具有较好保护作用,两者疗效相近。结论:国产与进口CDZ具有较强和相同的抗菌活性。     

In Vitro and In Vivo Study of Poly(ethylene glycol) Conjugated Ibuprofen to Extend the Duration of Action

Ibuprofen-polyethylene glycol (PEG) conjugates (PEG-Ibu) were prepared and their potential as a prolonged release system was investigated. Two PEG-Ibu conjugates were synthesized from Ibuprofen and PEG with two different molecular weights by esterification in the presence of DCC and DMAP. The PEG-Ibu conjugates were characterized by FT-IR, (1)H NMR, Mass spectroscopy and DSC analysis. The solubility study in aqueous system showed an increase in solubility of conjugates. The dissolution / hydrolysis studies showed a specific acid-base catalysis pattern dependent on the pH of the medium. This indicated a good chemical stability in aqueous buffer solution of acidic medium and the extended release behavior was found in both prodrugs after 9 hour. The results demonstrate that, in the same condition, the rate of hydrolysis for PEG(4000)-Ibu is slower than other. The Writhing induced by acetic acid experiment and paw edema test after oral administration showed that both conjugates had extended analgesic and anti-inflammatory effects compared with Ibuprofen. These results suggest that PEG-Ibu could be a promising NSAID prodrug with an extended pharmacological effect owing to delayed-release of parent drug.     

地非三唑抑制血管新生作用的研究

OBJECTIVE To investigate the effects of antiangiogenesis of DL111-IT in vivo and in vitro.METHODS To detect the inhibition ratio of DL111-IT on endothelial cells with the method of MTT.The different concentrations of DL111-IT were injected onto the 6th da     

Mechanisms of Action of Ribotoxins

Abstract

The ribotoxins α-sarcin and ricin and their homologs catalyze covalent modifications in adjacent nucleotides in the large RNA of ribosomes. α-Sarcin is a ribonuclease that cleaves the phosphodiester bond on the 3’ side of G4325 in a universal, 14-nucleotide, purine-rich sequence in 28SrRNA. The A-chain of ricin and of other related toxins such as Shiga toxin and Vero toxin is a RNA N-glycosidase that catalyses the depurination of the 5’ adjacent A4324. There are nearly 7000 nucleotides in mammalian ribosomes. The toxins, however, catalyze only a single covalent modification that inactivates the ribosomes and is entirely responsible for the toxicity.     

地非三唑抑制血管新生作用的研究

目的从细胞、器官、整体三个水平观察地非三唑抑制血管的新生作用。方法细胞水平用MTT法测定地非三唑对人脐静脉内皮细胞的增殖抑制作用;器官水平上利用鸡胚绒毛尿囊膜(CAM)血管新生模型,观察地非三唑抑制CAM血管新生的情况;并在整体水平上采用家兔角膜血管新生模型,于缝线后第3d用地非三唑于结膜囊注射给药,每天观察角膜血管新生情况。结果地非三唑能有效抑制人脐静脉EVC304细胞的增殖,其IC50根据药物作用时间的不同,维持在9~15μg.mL-1;并能使CAM新生血管明显减少甚至消失,对家兔角膜新生血管也有同样抑制作用。结论地非三唑能抑制血管新生作用。     

Actions of Fenfluramine on Glucose Uptake in Vitro and in Vivo

Abstract Fenfluramine stimulates the glucose uptake of the isolated hemi-diaphragm from normal and streptozotocin diabetic rats in the presence of insulin. The drug does not cause an increased storage of glycogen. During hind leg perfusion of the dog fenfluramine stimulated peripheral glucose uptake. No increase in lactate or in free fatty acids release was observed during prolonged infusions of the drug. Fenfluramine caused an improvement of glucose tolerance in normal glucose-primed rats. A single dose of fenfluramine significantly lowered the blood glucose levels in streptozotocin diabetic rats and in diabetic dogs treated with insulin. Prolonged treatment with fenfluramine of streptozotocin diabetic rats had no significant effect on blood glucose levels. Additional treatment for one week of insulin dependent diabetic dogs with small non-anorexic doses of fenfluramine resulted in slightly decreased blood glucose levels. The dogs could not be maintained on fenfluramine alone (without insulin).