二酰亚胺类G-四链体配体抑制白血病细胞增殖及其分子机制

为了解二酰亚胺类G一四链体配体对白血病细胞的增殖抑制作用及其分子机制,用不同浓度（0．1—10μmol／L）的二酰亚胺类G-四链体小分子配体处理体外培养的白血病细胞系K562,用台盼蓝染料排斥法了解小分子对K562细胞生长曲线的影响,脱氧核糖核苷酸末端转移酶介导的缺口末端标记法（TUNEL）检测细胞凋亡,端粒重复序列扩增法（TRAP）检测端粒酶活性变化,基因微阵列技术（Microarray）分析基因表达谱的变化,逆转录-聚合酶链反应（RT-PCR）验证基因表达谱的部分结果。结果表明,二酰亚胺类小分子能够抑制K562细胞的增殖并诱导其凋亡。二酰亚胺类小分子处理后白血病细胞中端粒酶活性降低,细胞凋亡相关基因、信号通路成员基因、原癌基因等重要生物学功能相关的基因转录水平发生显著变化。结论：二酰亚胺类G-四链体配体是一种能够抑制白血病细胞增殖、诱导其凋亡的小分子,这种抗肿瘤效应可能是通过抑制端粒酶活性和调节某些重要基因的表达而实现的。     

Fas/FasL信号转导通路在DADS诱导K562细胞凋亡中的作用机制研究

本研究旨在探讨二烯丙基二硫化合物(diallyl disulfide,DADS)诱导白血病K562细胞凋亡的作用及Fas/FasL信号转导通路在DADS诱导白血病K562细胞凋亡作用中机制。以K562细胞为研究外培养的细胞分为空白组(2组)及药物处理组(4组),共6小组。空白组包括细胞对照组及溶媒对照组,药物处理组加入不同浓度DADS,DADS终浓度为10、20、40、80mg/L。取对数生长期细胞进行实验。采用Hoechst33258染色法观察细胞凋亡形态学变化;流式细胞术分析不同浓度、不同时间DADS对K562细胞凋亡的诱导作用;RT-PCR法检测Fas、FasLmRNA表达变化。结果表明,DADS在浓度为10、20、40mg/L时,K562细胞以凋亡效应为主。K562细胞出现细胞核缩小,染色质凝集、核膜破裂等凋亡特征;同一时间组(作用细胞24小时),DADS浓度从10mg/L增至40mg/L,K562细胞的凋亡率由(2.10±0.25)%增至(37.94±0.87)%;同一浓度组(40mg/L),DADS作用时间从24小时增至72小时,K562细胞的凋亡率由(37.94±0.87)%增至(47.02±0.66)%,各实验组随时间、浓度增加凋亡率明显增高(p<0.01),呈现K562细胞的凋亡效用与药物浓度、时间明显依赖关系;作用48小时后,FasmRNA表达水平较对照组上调;FasLmRNA较对照组下调,差异具有统计学意义(p<0.05)。当DADS浓度为80mg/L时,K562细胞以坏死效应为主。结论 :DADS能够诱导K562细胞凋亡,其凋亡机制可能与上调Fas,下调FasL,激活Fas/FasL死亡受体通路有关。     

人前列腺凋亡反应因子4对K562细胞的促凋亡作用研究

前列腺凋亡反应因子4(prostate apoptosis response-4,Par-4)是Sells等[1]于1994年从前列腺肿瘤细胞中分离出来的一种促凋亡基因.国外学者发现Par-4能增强细胞对肿瘤坏死因子相关凋亡诱导剂(TRAIL)的敏感性,诱导细胞凋亡,提示Par-4在诱导白血病细胞凋亡中发挥重要作用.三氧化二砷(As2O3)不仅对急性早幼粒细胞白血病(APL)具有明显的疗效,对其他白血病细胞系HL-60、K562细胞以及某些实体瘤细胞也有明显的生长抑制和诱导凋亡作用[2].我们前期研究发现,Par-4不能直接诱导K562细胞凋亡,但是在As2O3诱导K562细胞凋亡的过程中,Par-4表达明显上调,提示Par-4参与K562细胞的凋亡调控.由于小剂量As2O3 对K562细胞的促凋亡作用较弱[3],因此我们在本实验中通过转染pIRES2-EGFP/Par-4真核表达载体,加用小剂量As2O3,进一步观察Par-4对K562细胞的促凋亡作用.     

靶向血管内皮生长因子siRNA对K562细胞凋亡及survivin表达的影响

目的 应用腺病毒介导的血管内皮生长因子(VEGF) siRNA沉默K562细胞中VEGF的表达,观察其对K562细胞凋亡及凋亡抑制基因survivin表达的影响.方法 应用成功构建的携带特异性VEGF siRNA的重组腺病毒(Ad5-VEGF siRNA)感染K562细胞,实验分为3组:实验组(K562/Ad5-VEGF siRNA组)、空载体组(K562/Ad5组)、对照组(K562组).通过RT-PCR法检测细胞内VEGF及survivin mRNA的表达,ELISA法检测细胞培养上清中VEGF蛋白表达,Western blot法检测细胞survivin蛋白表达,流式细胞术检测细胞凋亡.结果 实验组细胞VEGF及survivin mRNA表达水平较对照组均有明显降低(P＜0.01),且细胞培养上清中VEGF蛋白表达水平[(1121±15)pg/ml]低于空载体组[(1290±28)pg/ml]和对照组[(1303±28)pg/ml](P＜0.01).Western blot法检测结果显示,实验组survivin蛋白表达水平(0.26 ± 0.11)较对照组(0.74±0.10)也显著降低(P＜0.01).实验组细胞凋亡率与对照组比较明显增加(P＜0.01).结论 应用RNA干扰沉默K562细胞中VEGF基因表达后,survivin的表达也随之降低,同时细胞凋亡率相应增加.VEGF可诱导K562细胞中survivin基因表达,可能是survivin基因表达的上游调控因子.     

新型磷酸二酯酶4抑制剂ZL-n-91对白血病细胞增殖抑制作用的研究

目的:研究新型高选择性磷酸二酯酶4抑制剂ZL-n-91对白血病细胞L1210和K562增殖抑制的作用。方法:采用CCK-8法检测ZL-n-91对L1210和K562细胞增殖的影响,并计算增殖抑制率、半数抑制浓度(IC50); PE单染法检测ZL-n-91对L1210和K562细胞周期的影响;PE/7AA-D双染法检测ZL-n-91对L1210和K562细胞凋亡的影响;Western blot检测ZL-n-91对K562细胞凋亡相关蛋白表达水平的影响;构建急性淋巴细胞白血病L1210裸鼠皮下移植瘤模型,观察口服ZL-n-91对白血病L1210体内增殖抑制的效果。结果:ZL-n-91对白血病细胞L1210和K562具有显著的增殖抑制效果(P0.001),且抑制作用呈剂量依赖性。ZL-n-91处理后,白血病细胞L1210和K562细胞周期中S期的细胞减少,与对照组相比具有显著的统计学差异(P0.01)。ZL-n-91诱导L1210和K562白血病细胞发生凋亡(P0.001),凋亡相关蛋白BAX的表达显著增加。动物实验中,ZL-n-91可显著抑制白血病L1210皮下移植瘤的增殖(P0.05)。结论:新型磷酸二酯酶4抑制剂ZL-n-91能有效抑制白血病细胞L1210和K562的增殖,具有抗白血病药物开发的潜力。     

DLL4基因对白血病细胞株K562细胞中YY1和c-Myc蛋白表达及细胞增殖的影响

本研究旨在探讨Notch的配体DLL4基因在白血病细胞株K562中对转录因子YY1和原癌基因c-Myc蛋白表达及细胞生长的影响。实验分正常对照组、阴性对照组(转染质粒pBudCE4.1)和实验组(转染质粒pBudCE4.1-DLL4)。转染后48小时,用免疫印迹法和免疫细胞化学法检测外源性DLL4瞬时转染表达水平及YY1和c-Myc蛋白的表达水平;用细胞计数试剂盒-8法检测各组细胞的增殖;转染后48小时用流式细胞仪检测各组细胞的周期分布和凋亡。结果表明,在各组K562细胞中均检测到DLL4、YY1和c-Myc蛋白的表达,实验组的DLL4、YY1和c-Myc蛋白表达量比两个对照组显著增多(p<0.05);实验组K562细胞的生长速度明显低于对照组;实验组较对照组G0/G1期细胞增多(p<0.001),凋亡率增加(p<0.001)。结论:DLL4基因能增加细胞转录因子YY1和原癌基因c-Myc蛋白的表达,诱导细胞生长速度减慢、细胞周期停滞于G0/G1期,并能增高凋亡率增加。     

蛇六谷石油醚提取物对K562细胞生物学特性的影响及其机制

目的:探讨蛇六谷石油醚提取物(SLG)抑制白血病K562细胞增殖、促进凋亡和诱导分化的作用。方法:SLG处理K562细胞,同时加入ERK信号通路阻滞剂PD98059。采用MTT检测细胞活力,采用流式细胞术检测细胞凋亡率及分化相关抗原表达阳性的细胞比例,采用Western blot检测ERK1/2和p-ERK1/2的蛋白表达水平。结果:SLG 50、100、200 mg/L能够降低K562细胞的增殖活力,其抑制作用呈剂量依赖性(r=0.9997)。SLG能够提高细胞凋亡率及分化相关抗原CD11b、CD14和CD42b表达阳性的细胞比例,同时能够上调p-ERK1/2的表达。PD98059可部分逆转SLG促凋亡和分化的作用。结论:SLG通过ERK信号通路抑制K562细胞增殖、促进凋亡和诱导分化。     

赤芍总苷诱导K562细胞凋亡及对线粒体膜电位和Ca2+的影响

目的:赤芍总苷能诱导鼠HepA和S180细胞凋亡,但赤芍总苷能否抑制K562细胞增殖及其诱导K562细胞凋亡的机制尚不明确.观察赤芍总苷诱导人红白血病细胞株K562细胞凋亡及线粒体膜电位与Ca2 水平的变化,以探讨凋亡机制.方法:实验于2007-03-02/2007-10-20在北京中医药大学细胞生化实验室,国家重点实验完成.①实验材料:赤芍总苷由西安奥晶科技发展有限公司提供,批号:060417,纯度>95%.人红白血病K562细胞株购自上海中科院细胞库.②实验方法:取对数生长期的K562细胞,培养24 h后加入50 mg/L赤芍总苷进行干预,光镜下观察细胞形态.MTT显色法检测25,50,75,100,150,200,400 mg/L赤芍总苷对K562细胞增殖的抑制作用,以仅加入无血清培养基培养的为对照.③实验评估:采用Annexin V/PI双标记法检测凋亡效应,罗丹明123(Rh123)染色流式检测线粒体膜电位和荧光染料Fluo-3AM流式检测K562细胞内游离Ca2 浓度.结果:①50 mg/L 赤芍总苷作用K562细胞24 h后,出现核固缩、核碎裂和凋亡小体等形态学改变.②与对照组相比,不同质量浓度赤芍总苷能明显抑制K562细胞的增殖(P < 0.01),并具有量效关系,呈时间和剂量依赖性.③细胞线粒体经Rh123染色呈现明亮绿,不同质量浓度赤芍总苷干预组荧光强度均较对照组明显减弱,膜电位水平较高.④赤芍总苷可引起细胞线粒体膜电位下降.不同质量浓度赤芍总苷组细胞内游离Ca2 浓度均升高, 线粒体膜电位下降,与对照组比较差异显著(P < 0.01).结论:赤芍总苷诱导K562细胞凋亡的可能机制是通过减低细胞内线粒体膜电位及提高游离Ca2 水平,从而导致细胞凋亡.     

三氧化二砷抑制K562/ADM细胞 P-糖蛋白表达并提高化疗药物的敏感性

目的 研究三氧化二砷（As2O3)对人多药耐药白血病细胞K562/ADM的诱导凋亡作用和对P-糖蛋白（P-gp)表达及功能的影响。以及As2O3与常规化疗药物对耐药细胞的联合效应。方法 以白血病多药耐药细胞系K562/ADM为As2O3作用的靶细胞，用MTT比色法检测细胞增殖活性。光镜，激光共聚焦显微镜和电镜观察形态学变化，流式细胞术进行细胞周期分析和P-gp表达的检测，激光共聚焦显微镜检测P-gp功能。结果 K562/ADM细胞对阿霉素（ADM）高度耐受，并与柔红霉素（DNR）和足叶乙甙（Vp16)交叉耐药，0.5-20.0μmol/LAs2O3抑制K562/ADM细胞增殖。抑制活性高于K562细胞。经As2O3诱导后K562/ADM细胞出现典型的凋亡形态学变化和亚G1期细胞比例增高等凋亡特征性改变。As2O3下调K562/ADM细胞P-gp的表达并抑制其功能，增加K562/ADM细胞对ADM，DNR和Vp16的敏感性。结论 As2O3能够诱导白血病多药耐药细胞凋亡。并通过抑制耐药细胞P-gp的表达和功能提高耐药白血病细胞对常规化疗药物的敏感性。     

三氧化二砷对K562/ADM耐药细胞凋亡抑制的逆转作用

目的:研究三氧化二砷(As2O3)诱导白血病K562/ADM耐药细胞凋亡的分子机制。方法:采用MTT比色法检测K562/ADM耐药细胞增殖活性,细胞形态学和annexinV /PI双染色检测细胞凋亡,RT-PCR检测mdr1、bcl-2和caspase-3基因mRNA的表达水平,流式细胞法(FCM)测定P-糖蛋白(P -glycoprotein,P-gp)和bcl-2蛋白表达及caspase-3活性。结果:As2O3显著抑制K562/ADM耐药细胞的增殖;经 As2O3处理后细胞形态上出现典型的凋亡改变,annexinV /PI双染显示凋亡细胞明显增加;mdr1mRNA表达和P-gp合成明显降低,凋亡抑制基因bcl-2mRNA及其蛋白bcl-2表达下调, caspase-3mRNA表达和caspase-3活性显著增强。结论:As2O3诱导K562/ADM耐药细胞凋亡,其主要机制可能为As2O3抑制 mdr1和bcl-2基因表达,逆转耐药白血病细胞因bcl-2和P-gp高表达所介导的凋亡抑制。     

Inhalation delivery of Telmisartan enhances intratumoral distribution of nanoparticles in lung cancer models

The purpose of the present study was to evaluate the effect of Telmisartan (Tel) and Losartan (Los) on nanoparticle intratumoral distribution and anticancer effects in lung cancer. A549 lung tumor cells were orthotopically and metastatically administered to Nu/nu mice. Fluorescent polystyrene nanoparticles (FPNPs, size ~ 200 nm) beads were used to study their intratumoral distribution after Tel and Los treatments. Animals were administered with FPNPs and after 2 h, FPNPs intratumoral distribution was studied by fluorescent microscopy. Tel (~ 1.12 mg/kg) and Los (~ 4.5 mg/kg) were administered by inhalation delivery at alternative days for 4 weeks to tumor bearing animals. Collagen-1, transforming growth factor beta 1 (TGF-β1), cleaved caspase-3, Vimentin and E-Cadherin expressions were studied by western blotting. To correlate the AT₁ receptor blockage to anticancer effects, VEGF levels and microvessel densities (MVD) were quantified. Los and Tel treated group resulted in the 5.33 and 14.33 fold increase respectively in the FPNPs intratumoral distribution as compared to the controls. Tel treatment attenuated 2.23 and 1.70 fold Collagen 1 expression compared to untreated control and Los groups, respectively. Further, in Tel and Los treated groups, the TGF-β1 active levels were significantly (p < 0.05) decreased. Tel (at four times less dose) was 1.89 and 1.92 fold superior in anticancer activity to Los respectively in A549 orthotopic and metastatic tumor models (p < 0.05) when given by inhalation route. Tel, by virtue of its dual pharmacophoric nature could be an ideal candidate for combination therapy to improve the nanoparticle intratumoral distribution and anticancer effects.     

Telmisartan at 80 mg/Day Increases High-Molecular-Weight Adiponectin Levels and Improves Insulin Resistance in Diabetic Patients

Introduction

The clinical dose of telmisartan necessary for activation of peroxisome proliferator-activated receptor gamma (PPAR-gamma) has not been established. The authors investigated the effect of high-dose telmisartan on serum levels of the high-molecular-weight (HMW) adiponectin in patients with diabetes and hypertension.

Methods

In this open-label, prospective, randomized study, patients with type 2 diabetes and hypertension with poor control of blood pressure by 40 mg/day telmisartan were randomly assigned into the telmisartan 80 mg/day (Tel80) group (dose increase from 40 to 80 mg/day) or the telmisartan 40 mg + amlodipine 5 mg (Tel40 + Aml5) group. Serum levels of HMW adiponectin and parameters of glucose and lipid metabolism were measured at baseline and end of 3-months of treatment.

Results

Although the antihypertensive effects of the two doses of telmisartan were similar, a significant increase in HMW adiponectin levels was noted only in the Tel80 group. The increase was evident particularly in a group of patients whose HMW adiponectin levels were less than 4.0 ??g/dL. A significant improvement in homeostasis model assessment of insulin resistance (HOMA-IR), a measure of insulin resistance, was also observed in the Tel80 group only.

Conclusions

In diabetic patients with hypertension, high-dose telmisartan increased HMW adiponectin levels and improved insulin resistance through activation of PPAR-gamma.     

Muscarinic cholinergic modulation of prepulse inhibition of the acoustic startle reflex

The purpose of the present study was to determine the effects of muscarinic cholinergic receptor antagonists and agonists on prepulse inhibition (PPI) of the acoustic startle reflex in rats. The muscarinic receptor antagonist scopolamine (0.03-1.0 mg/kg) produced a significant dose-dependent decrease in PPI without affecting startle amplitude. In contrast, N-methyl scopolamine, the quaternary analog of scopolamine, had no effect on PPI, indicating that scopolamine disrupted PPI through a central cholinergic mechanism. Two other muscarinic receptor antagonists, trihexyphenidyl (0.3-10 mg/kg) and benztropine (0.03-10 mg/kg), produced significant decreases in PPI similar to scopolamine. On the other hand, the muscarinic receptor antagonists dicyclomine (0.03-10 mg/kg) and biperiden (0.03-10 mg/kg) had no effect on PPI but significantly decreased startle amplitude. Mecamylamine (0.1-10 mg/kg), a nicotinic receptor antagonist, also had no effect on PPI. Administered alone, the muscarinic receptor agonists pilocarpine (0. 03-10 mg/kg), oxotremorine (0.01-0.3 mg/kg), RS-86 (0.1-3.0 mg/kg), and arecoline (0.3-10 mg/kg), as well as the cholinesterase inhibitors physostigmine (0.01-0.3 mg/kg) and tacrine (0.03-10 mg/kg), had no effect on PPI, but each produced significant decreases in startle amplitude at the highest doses tested. In addition, the disruption of PPI by scopolamine was reversed in a dose-dependent manner by the muscarinic receptor agonist oxotremorine. The present findings demonstrate that the muscarinic cholinergic system plays an important role in the normal mechanisms of PPI.     

Beneficial effects of a 5-lipoxygenase inhibitor in endotoxic shock in the rat

The effects of a highly selective 5-lipoxygenase inhibitor, CGS8515 [methyl 2-[(3,4-dihydro-3,4-dioxo-1-naphthalenyl) amino]benzoate], on endotoxic shock sequelae and eicosanoid synthesis by peritoneal macrophages were evaluated in the rat. Pretreatment of peritoneal macrophages in vitro with CGS8515 significantly inhibited the synthesis (P less than .01) of immunoreactive leukotriene C4/leukotriene D4 stimulated by the calcium ionophore (A23187). Inhibition of 5-lipoxygenase produced significant shunting to immunoreactive thromboxane B2 formation (P less than .05). In rats sedated with ketamine.HCl (82.5 mg/kg) and xylazine. HCl (27.5 mg/kg), i.v. injection of Salmonella enteritidis endotoxin (25 mg/kg i.v.) produced significant decreases at 30 min in mean arterial pressure (from 89 +/- 4 to 44 +/- 8 mm Hg, N = 5, P less than .001); in white blood cell count (from 10.8 +/- 0.6 to 6.5 +/- 0.8 x 10(3)/mm3, N = 5, P less than .01); in platelet count (from 687 +/- 66 to 392 +/- 65 x 10(3)/mm3, N = 5, P less than .01); and produced an increase of hematocrit (from 46 +/- 1.2 to 57.4 +/- 1.8%, N = 5, P less than .03). CGS8515 (5 mg/kg i.v. 30 min before endotoxin injection, N = 6) blunted the endotoxin-induced hypotension by 35% (P less than .001), the leukopenia by 24% (P less than .03), the thrombocytopenia by 45% (P less than .006) and the hemoconcentration by 16% (P less than .03), compared to the shocked control rats 30 min after endotoxin injection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Analgesic and toxic effects of ABT-594 resemble epibatidine and nicotine in rats

The present study directly compared the antinociceptive and toxic effects of the neuronal nicotinic receptor agonist ABT-594 ((R)-5-(2-azetidinylmethoxy)-2-chloropyridine) with (-)-nicotine and (+)-epibatidine. Like (-)-nicotine (0.8 and 1.6 mg/kg s.c.) and (+)-epibatidine (0.005 and 0.01 mg/kg s.c.), ABT-594 (0.05 and 0.1 mg/kg s.c.) increased response latencies in the hot-plate test in rats, indicating that it has antinociceptive activity. In contrast to (-)-nicotine and (+)-epibatidine, ABT-594 did not cause rotarod impairment at antinociceptive doses but did cause hypothermia and life-threatening adverse effects including seizures. ABT-594 (0.01 and 0.1 mg/kg i.v.) also produced a dose-dependent increase in blood pressure resembling that observed with (-)-nicotine (0.03, 0.1 and 0. 03 mg/kg i.v.) and (+)-epibatidine (0.001 and 0.003 mg/kg i.v.). Both the antinociceptive and toxic effects (convulsions and hypertension) were abolished by pretreatment with the brain penetrant neuronal nAChR antagonist mecamylamine (1 mg/kg s.c.; i.v. for cardiovascular studies), demonstrating that these actions of ABT-594 were mediated via activation of neuronal nicotinic receptors. Continuous infusion of ABT-594 (0.2 mg/kg per day s.c.) to rats for 7 days followed by challenge with mecamylamine (1 mg/kg i.p.) induced a nicotine-like abstinence syndrome suggesting that ABT-594 has nicotine-like dependence liability. These findings indicate that the acute safety profile of ABT-594 is not significantly improved over other nicotinic analgesics.     

组织多普勒Tei指数评价妊娠高血压疾病胎儿右心整体功能的价值

目的通过检测胎儿右心组织多普勒Tei指数,了解妊娠高血压疾病(PIH)对胎儿右心整体功能的影响。方法 92例PIH孕妇,其中重度子痫前期组14例,轻度子痫前期组26例,妊娠高血压组52例,60例与其孕龄匹配且血压正常孕妇为对照组,应用组织多普勒检测胎儿右心室的等容收缩时间、等容舒张时间及射血时间,并计算Tei指数;于治疗后24 h和72 h监测重度子痫前期组胎儿Tei指数。结果对照组、妊娠高血压组及轻度子痫前期组的Tei指数分别为0.43±0.03、0.44±0.04、0.48±0.04,组间比较差异均无统计学意义(P0.05);重度子痫前期组Tei指数为0.59±0.05,高于对照组、妊娠高血压组及轻度子痫前期组(P0.05);重度子痫前期组胎儿治疗后24 h,Tei指数为0.54±0.05,与治疗前比较差异无统计学意义(P0.05);治疗后72 h Tei指数为0.46±0.04,较治疗前减低(P0.05)。结论检测胎儿右心组织多普勒Tei指数可以定量判断其右心整体功能的改变,为临床提供治疗及预后依据。     

Comparison of a New Triazole Antifungal Agent, Schering 56592, with Itraconazole and Amphotericin B for Treatment of Histoplasmosis in Immunocompetent Mice

A murine model of intratracheally induced histoplasmosis was used to evaluate a new triazole antifungal agent, Schering (SCH) 56592, for treatment of histoplasmosis. MICs were determined for SCH 56592, amphotericin B, and itraconazole by testing yeast-phase isolates from 20 patients by a macrobroth dilution method. The MICs at which 90% of the isolates are inhibited were for 0.019 μg/ml for SCH 56592, 0.5 μg/ml for amphotericin B, and ≤0.019 μg/ml for itraconazole. Survival studies were done on groups of 10 B6C3F₁ mice with a lethal inoculum of 10⁵. All mice receiving 5, 1, or 0.25 mg of SCH 56592 per kg of body weight per day, 2.5 mg of amphotericin B per kg every other day (qod), or 75 mg of itraconazole per kg per day survived to day 29. Only 44% of mice receiving 5 mg of itraconazole/kg/day survived to day 29. Fungal burden studies done in similar groups of mice with a sublethal inoculum of 10⁴ showed a reduction in CFUs and Histoplasma antigen levels in lung and spleen tissue in animals treated with 2 mg of amphotericin B/kg qod, 1 mg of SCH 56592/kg/day, and 75 mg of itraconazole/kg/day, but not in those treated with lower doses of the study drugs (0.2 mg of amphotericin B/kg qod, 0.1 mg of SCH 56592/kg/day, or 10 mg of itraconazole/kg/day). Serum drug concentrations were measured 3 and 24 h after the last dose in mice (groups of five to seven mice), each treated for 7 days with SCH 56592 (10 and 1 mg/kg/day) and itraconazole (75 and 10 mg/kg/day). Mean levels measured by bioassay were as follows: SCH 56592, 10 mg/kg/day (2.15 μg/ml at 3 h and 0.35 μg/ml at 24 h); SCH 56592, 1 mg/kg/day (0.54 μg/ml at 3 h and none detected at 24 h); itraconazole, 75 mg/kg/day (22.53 μg/ml at 3 h and none detected at 24 h); itraconazole, 10 mg/kg/day (1.33 μg/ml at 3 h and none detected at 24 h). Confirmatory results were obtained by high-pressure liquid chromatography assay. These studies show SCH 56592 to be a promising candidate for studies of treatment of histoplasmosis in humans.     

气体信号分子硫化氢在热性惊厥脑损伤形成机制中的作用

目的:探讨硫化氢(H2S)对反复热性惊厥(febrile seizures,FS)脑损伤的影响。方法:大鼠随机分为对照组、FS组、FS+NaHS组、FS+HA(hydroxylamine)组。采用热水浴诱导大鼠FS,隔日诱导1次,共10次。记录大鼠惊厥潜伏期、持续时间及强度;分光光度计法测定大鼠血浆中H~2|S含量;电镜观察海马神经元超微结构的改变;Timm染色观察海马发芽情况;原位杂交和免疫组化分别观察c-fos基因和Fos蛋白表达情况。结果:FS+NaHS组和FS+HA组大鼠惊厥潜伏期、持续时间及强度的改变与FS组相比无明显差异;FS+NaHS组大鼠海马神经元超微结构损伤性改变较FS组明显减轻,而FS+HA组则明显加重;NaHS干预后海马苔藓纤维发芽减轻,而HA干预后海马发芽加重;NaHS的干预使c-fos基因和Fos蛋白表达降低,而HA的干预使其表达增强。结论:应用H~2|S外源性供体NaHS和胱硫醚-β-合成酶抑制剂HA的干预研究表明,气体信号分子硫化氢参与了热性惊厥脑损伤的发生与发展过程。     

核因子κB抑制剂PDTC对颈椎病大鼠椎间盘炎症反应的抑制作用

目的探讨核因子κB(NF-κB)抑制剂吡咯烷二硫基甲酸盐(PDTC)对颈椎病大鼠椎间盘炎症反应的抑制作用。方法构建动静力失衡性颈椎病大鼠模型,将造模成功大鼠分为模型组,PDTC低、中、高剂量组,另外设立假手术组(仅切开颈部皮肤),每组大鼠10只,PDTC低、中、高剂量组大鼠每天分别腹腔注射50 mg/kg、100 mg/kg、200 mg/kg PDTC,假手术组及模型组腹腔注射等量生理盐水,连续28 d。酶联免疫吸附试验(ELISA)检测各组大鼠椎间盘组织中肿瘤坏死因子-α(TNF-α),白介素-1β(IL-1β)及IL-6含量,Realtime PCR检测TNF-α,IL-1β及IL-6 mRNA表达,Western blot检测各组大鼠椎间盘组织中NF-κB p65、NF-κB抑制蛋白(IκBα)表达。结果与假手术组比较,模型组中大鼠椎间盘组织中TNF-α,IL-1β及IL-6 mRNA及蛋白含量提高(P <0. 05),p-NF-κB p65、p-IκBα表达量上调(P <0. 05)。与模型组比较,PDTC低、中、高剂量组大鼠椎间盘组织中TNF-α,IL-1β及IL-6 mRNA及蛋白含量降低(P <0. 05),p-NF-κB p65、p-IκBα表达量下调(P <0. 05),并呈剂量依赖性。结论 PDTC能显著地抑制颈椎病大鼠椎间盘炎症反应,并其作用呈剂量依赖性。     

Comparative cochlear toxicities of streptomycin,gentamicin, amikacin and netilmicin in guinea-pigs

All the aminoglycoside antibiotics now in clinical use are ototoxic. This study was designed to compare the toxic effects of four aminoglycoside antibiotics, streptomycin, gentamicin, amikacin and netilmicin, administered to guinea-pigs systemically (at respective doses of 125 mg/kg, 50 mg/kg, 150 mg/kg or 37.5 mg/kg, twice daily for 1 week) or topically via the transtympanic route (0.25 ml/kg in 4% saline, twice daily for 1 week). Chosen doses were 10-20 times higher than the recommended human dosage. Cochlear damage was observed in all animals that were given systemic and local aminoglycosides. The severity of the cochlear damage was in the order gentamicin, amikacin, streptomycin, netilmicin, with gentamicin being the most toxic. No statistically significant difference between the severity of cochlear damage resulting from the systemic and topical applications was detected.