睾丸特异性含溴结构域的蛋白作为潜在男性抗生育药物靶标的研究进展

哺乳动物的四种含溴结构域蛋白(BET)基因在精子发生不同阶段均有表达,其中睾丸特异表达的bromodomain-containing protein(BRDT)对精子发生必不可少。BRDT在核染色质重组中起关键作用,也参与基因转录和共转录调节。BRDT的第一个溴结构域缺失导致圆形精子细胞错误伸长、精子形态严重缺陷,而圆形精子细胞的错误伸长与减数分裂之后染色质结构异常相关。另外,BRDT是形成圆形精子细胞染色质核仁所必需的;精母细胞和精子细胞缺乏全长的BRDT将会导致转录和可变剪接过程发生改变。动物实验证实一种小分子的BRDT抑制剂(JQ1),具有良好的抗生育作用,这为进一步开发可逆的男性抗生育药物开辟了新思路。     

基于网络药理学及分子对接方法探讨当归补血汤治疗慢性肾脏病的作用机制

目的:基于网络药理学及分子对接方法分析当归补血汤治疗慢性肾脏病的作用机制,构建慢性肾衰竭大鼠模型进行实验验证。方法:利用数据库筛选当归补血汤活性成分及靶点、慢性肾脏病疾病靶点,取二者交集,构建蛋白互作(PPI)网络模型,对交集靶点进行GO与KEGG通路富集分析,构建药物-疾病靶点-通路网络图,得到当归补血汤治疗慢性肾脏病的关键靶点。对药物核心成分和疾病靶蛋白进行分子对接。构建慢性肾衰竭大鼠模型,运用免疫组化及Western Blotting方法对核心靶点进行验证。结果:(1)当归补血汤治疗慢性肾脏病的潜在靶点涉及氧化应激、细胞粘附、凋亡等生物学过程,涉及蛋白激酶复合物、细胞外基质等细胞组成,涉及蛋白激酶活性、DNA结合转录因子结合、细胞因子受体结合等分子功能,涉及NF-κB信号通路、FoxO信号通路等多种信号途径。(2)筛选关键基因SIRT1、TLR4、MCP-1与当归补血汤主要活性成分黄芪甲苷、毛蕊异黄酮、槲皮素进行分子对接,配体化合物均能良好的包埋在受体靶蛋白的活性口袋中。(3)构建慢性肾衰竭大鼠模型,给予当归补血汤结肠透析治疗,与正常组相比,CRF模型组肾组织SIRT1、Clau...     

利用cDNA微阵列技术筛选成年期与胚胎期睾丸差异表达基因——钙联接蛋白基因

目的 :用cDNA微阵列技术克隆和筛选成年期与胚胎期睾丸差异表达基因 ,以进行睾丸发育及精子发生的调控研究。　方法 :构建人睾丸cDNA芯片 ,分别用正常成人及胚胎睾丸的mRNA探针进行杂交 ,对成人和胚胎睾丸中差异表达的基因进行高流量的比较。　结果 :发现 1条成人睾丸高表达、胚胎低表达的基因———钙联接蛋白 (CLGN)基因。　结论 :运用cDNA微阵列方法可筛选到成年期与胚胎期睾丸差异表达基因     

实验性精索静脉曲张对青春期大鼠睾丸、附睾中CRES蛋白表达的影响

目的:研究青春期大鼠实验性左侧精索静脉曲张(ELV)对睾丸和附睾中胱蛋白酶抑制剂相关的附睾精子发生(CRES)蛋白表达的影响,探索精索静脉曲张导致不育的机制。方法:建立青春期雄性SD大鼠ELV模型,采用免疫组化及蛋白印迹方法检测CRES蛋白在ELV 2周组(n=8)、4周组(n=8)及其相应的对照组(n均=5)大鼠睾丸和附睾头、体、尾中的表达变化。结果:免疫组化显示,CRES蛋白在ELV实验组和对照组大鼠睾丸和附睾中均有表达。在睾丸中,CRES蛋白主要定位于圆形和长形精子细胞的胞质、精子的顶体以及残余体中,其表达与生精周期密切相关,Ⅰ~Ⅲ和Ⅸ~ⅩⅣ期表达最强,Ⅶ~Ⅷ期表达次之,Ⅳ~Ⅵ期表达减弱。在附睾中,CRES蛋白主要表达于从附睾起始段到尾部的上皮主细胞的胞质中,且以体、尾部表达最强,头部次之,管腔分泌物也呈阳性表达。实验组比对照组CRES蛋白表达增强。W estern印迹显示:实验组和对照组大鼠睾丸和附睾在相对分子质量(Mr)为19 000和14 000处均可见CRES蛋白条带,其中以Mr19 000处表达更为明显。实验组CRES蛋白的表达比对照组明显增强。对免疫组化和W estern印迹结果进行灰度值和积分吸光度值(IA)测定,并经统计学分析显示:ELV 2周组和4周组比其相对应的对照组表达增强且差异有显著性(P<0.05或P<0.01),而ELV各组间未见CRES蛋白表达有明显差异(P>0.05)。结论:CRES蛋白在大鼠睾丸和附睾中均有表达,睾丸中表达呈现生精周期特异性和细胞特异性,附睾中表达呈现附睾上皮区段和细胞特异性;CRES蛋白在青春期ELV大鼠睾丸和附睾中的表达比对照组明显增强。这些结果提示CRES蛋白在精子发生和精子成熟过程中可能起着重要的作用,并且可能与ELV引起的不育或生育力低下有关。     

Nature:缺氧诱导因子-2α拮抗剂对临床前肾癌模型的疗效评价研究

正透明细胞型肾细胞癌(ccRCC)是一类最常见的肾癌,在其癌细胞中,肿瘤抑制蛋白pVHL通常表达失活,导致缺氧诱导因子-2α(HIF-2)累积。HIF-2α是一种细胞核转录因子,具备bHLH-PAS蛋白结构域,参与了与血管生成有关的多种肿瘤形成过程,长期以来被认为无法做为理想的药物靶标。但有学者不断研究发现了一种类似药物的小分子化合物PT2399,可与HIF-2α蛋白PAS-B结构域结合,发挥     

溴结构域蛋白4通过Noxa诱导骨肉瘤细胞凋亡的机制

目的:探讨溴结构域蛋白4(BRD4)通过Noxa诱导骨肉瘤细胞凋亡的机制。方法:采用小分子干扰RNA(siRNA)沉默骨肉瘤细胞中BRD4的表达,通过蛋白质印迹法(Western blot)和实时荧光定量聚合酶链反应(RT-qPCR)检测Noxa及凋亡相关分子表达;应用BRD4降解剂ARV-825处理骨肉瘤细胞,通过W...     

硫酸对甲酚的毒性及其清除措施研究进展

目前已证实的尿毒素有90多种,按分子量大小分为小分子毒素（分子量＜500 Da）、中分子毒素（分子量500~5 000 Da）和大分子毒素（分子量〉5 000 Da）.这些毒素,绝大部分游离于血浆和组织液中,不与蛋白和脂肪结合;晚近研究发现有部分毒素能与蛋白结合,称为蛋白结合毒素（protein-bound uremic toxins）,已报道的蛋白结合毒素多达32种[1].普通血液透析,对小分子水溶性毒素清除效果良好;通过采取高通透析器和透析滤过等方法,也能很好地清除游离的中分子毒素和大分子毒素（譬如β2微球蛋白）.     

大鼠精索静脉曲张睾丸组织的蛋白质组学研究

目的精索静脉曲张是男性不育的首要病因,本课题利用蛋白组学技术筛选精索静脉曲张大鼠睾丸中表达变化显著蛋白,探索精索静脉曲张引起不育的可能分子机制。方法雄性Wistar大鼠16只,随机分为对照组和精索静脉曲张实验组。实验组大鼠施行左肾静脉部分结扎术来诱导产生精索静脉曲张,对照组行假手术作为阴性对照。30d后,收集全部大鼠的左侧睾丸。采用原位末端脱氧核苷酸转移酶标记（Tunel）法检测两组大鼠生精细胞凋亡情况,进而比较两组生精细胞的凋亡指数。利用双向凝胶电泳技术（2-DE）寻找两组大鼠睾丸中表达有显著性差异的蛋白质点,然后进行基质辅助激光解析离子化飞行时间质谱鉴定（MALDI-TOFMS）。结果双向凝胶电泳结果显示21个蛋白质点在两组间存在显著性差异。在精索静脉曲张大鼠睾丸中有8个蛋白质点表达上升、13个下降,这些蛋白功能涉及蛋白质合成、加工、降解,基因表达调控,信号转导,能量代谢,凋亡,自由基代谢等。Tunel证实实验组大鼠睾丸中生精细胞凋亡指数显著高于对照组,且本实验筛选出14—3—3e、hnRNPF以及LZTFL1三种蛋白与凋亡相关。结论蛋白组学筛选出精索静脉曲张大鼠睾丸差异表达蛋白,并进一步证实精索静脉曲张促进睾丸生精细胞凋亡,其中相关凋亡蛋白对揭示精索静脉曲张引起男性不育的分子机制提供了可能。     

基于网络药理学和分子对接探讨补肾活血汤“从虚从瘀”治疗骨质疏松症的分子机制

目的采用网络药理学和分子对接技术探索补肾活血汤"从虚从瘀"治疗骨质疏松症(osteoporosis,OP)的内在分子机制。方法将补肾活血汤中的药物在TCMSP、Batman-TCM、化学数据库、TCMID数据库和知网上收集相关化学成分及作用靶点,然后对靶点进行基因注释;对Gene Cards和OMIM数据库进行疾病相关靶点检索,获取其对应靶点;然后通过Cytoscape3.7.2软件将药物成分、疾病及靶点的对应关系构建"中药-成分-靶点-疾病"网络可视化,并从String数据库获取交集靶点数据,构建蛋白互作网络;利用R语言软件对基因进行GO和KEGG富集分析;最后对核心化合物及靶点进行分子对接。结果共获取补肾活血汤活性化合物171种,共筛选出11个核心成分,预测出对应靶点166个; OP相关靶点1 335个,两者的交集基因共54个;利用PPI蛋白网络共筛选到13个核心靶点蛋白; GO和KEGG富集分析分别得到279个、63个富集结果;分子对接结果显示补肾活血汤治疗骨质疏松过程中,其核心化合物豆甾醇与MAPK1、PPARG以及β-谷甾醇与PPARG具有良好的结合性能。结论补肾活血汤通过营养支持、免疫调节和抗炎、损伤修复等方面发挥其重要作用,通过网络药理学和分子对接阐释了其"从虚从瘀"治疗骨质疏松的内在分子机制。     

Ccdc70基因在小鼠睾丸精子发生过程中的表达特征

目的:探讨Ccdc70(Coiled-coil domain containing 70)基因在小鼠睾丸中的表达特征并分析其在生精过程中的潜在功能。方法:经表达谱芯片筛选出小鼠睾丸特异性基因Ccdc70,通过RT-PCR、real-time PCR、Western印迹及免疫组化检测Ccdc70基因在成年小鼠睾丸中表达特征,并对该蛋白做相关的生物信息学分析。结果:RT-PCR、real-time PCR和Western印迹结果表明Ccdc70基因在小鼠睾丸中高表达,在附睾中低表达;免疫组化结果表明Ccdc70蛋白在睾丸中主要表达于小鼠精母细胞和圆形精子胞质,在附睾中主要表达在附睾管上皮细胞。生物信息学分析显示该蛋白存在一个CCDC结构域,并在哺乳动物进化过程中高度保守。结论:Ccdc70为小鼠睾丸高表达基因,且主要表达于精母细胞、圆形精子及附睾管上皮细胞,提示其可能参与调控小鼠精子发生过程及附睾精子的进一步成熟。     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Dilemma of Membrane Biocompatibility and Reuse

Abstract: Numerous articles have been published on the multiple use of dialyzers and on the effect of different reprocessing chemicals and techniques on the dialyzer biocompatibility and performance. The results often appear contradictory, especially those comparing standard biocompatibility parameters. Despite this confusion, a discerning review of the published works allows certain limited conclusions to be drawn. Reprocessing of used hemodialyzers changes the biocompatibility profile of a dialyzer as defined by the parameters complement activation. leukopenia, and cytokine release. The effect of reprocessing depends on the chemicals and reprocessing technique applied and also on the type of membrane polymer being subjected to the reprocessing procedure. Reports of pyrogenic reactions indicate that the flux of the membrane also influences how suitable it is for safe reuse. An increased risk of allergic and pyrogenic reactions appears to be associated with dialyzer reuse. Furthermore, there has been a lack of investigations into the immunologic effect of the layer of adsorbed and chemically altered proteins that remains on the inner surface of reprocessed dialyzers. We conclude that the clinical benefit of dialyzer reuse cannot be generally accepted from a biocompatibility point of view.