Notch信号通路和Notch相关疾病

Notch信号通路是一条进化上十分保守的信号转导系统。Notch受体通过与配体的相互作用转导细胞信号。从而在细胞增殖、分化、凋亡中发挥重要的调控作用。Notch信号通路中某些分子的基因突变与多种疾病的发生发展有关。如肿瘤、遗传性疾病、自身免疫性疾病等。另外,Notch信号通路在同一疾病的不同类型载不同发展阶段起的作用也不尽相同。     

Notch信号通路调控缺血性疾病过程的研究进展

心、肾及脑等组织的缺血可引起体内血管受损等一系列病理生理过程,缺血损伤后的血管修复与功能重建一直是缺血性疾病治疗上尚末解决的难题.Notch信号通路是进化中高度保守的信号转导通路,其调控细胞增殖、分化和凋亡的功能几乎涉及所有组织和器官.近年来研究表明Notch信号通路与血管新生以及缺血性疾病的调控有着密切的联系,且有报...     

Notch信号通路对成年哺乳动物中枢神经系统的调控

生理情况下Notch通路不仅对成年神经干细胞数量的维持和自我更新发挥着决定性的作用,而且还可以抑制其向神经元分化,促进其向神经胶质细胞分化.脑缺血发生后,Notch信号通路被激活以调控缺血后脑损害区域的结构和功能重建.此文将主要综述Notch信号通路及其在生理和病理情况下对成年哺乳动物中枢神经系统的调控.     

Notch信号通路调控Tip内皮细胞及血管新生过程研究进展

正Notch受体基因由遗传学家Morgan等首次在果蝇中发现并命名。1983年Notch基因被成功克隆,发现其编码两千多个氨基酸残基组成的一类大的跨膜受体[1]即Notch受体,后续研究中,研究者把与之相关表达的信号通路称为Notch信号通路。Notch信号通路被激活后,引发一系列分子反应,通过细胞间信号通路相互作用调控细胞的表型、增殖、分化、迁移及凋亡等一系列细胞生理、病理     

Notch信号通路与重要器官损伤研究进展

背景 Notch信号通路高度保守,但在细胞分化增殖和器官个体发育中发挥重要的调控作用,并会对细胞的各种应急事件作出反应,参与各器官损伤的调节机制. 目的 综述Notch信号通路在重要器官损伤机制中的研究进展. 内容 介绍Notch信号通路基本组成及调节,及其在脑、心肌、肺、肝及肾等重要器官损伤中的作用及相关机制. 趋向 Notch信号通路在不同器官损伤机制中的作用不同,对Notch信号通路的进一步深入研究,可能为器官损伤的预防和保护提供新的思路和手段.     

Notch和TGF信号通路对话在肾间质纤维化的研究

肾间质纤维化是许多慢性肾脏疾病发展过程中的必经阶段,信号通路调控多种功能基因的转录和参与许多重要的生理病理过程,信号通路在肾间质纤维化发生、发展过程中发挥着重要作用,其中TGF和Notch信号通路均参与肾纤维化的发生、发展,通过干预TGF和Notch信号通路可延缓肾间质纤维化的进展。研究表明,TGF信号通路与Notch信号通路既独立发挥作用,又存在对话间相互作用。既调控各信号通路组分的活性,又调控共同下游靶基因和表达产物,由此调节肾间质纤维化的发生、发展。因此,进一步研究两条通路的关系可能为抗肾纤维化研究提供新切入点。     

Notch信号通路与肝癌细胞凋亡关系的研究进展

肝癌细胞中Notch信号通路异常传导,因肝癌细胞异质性,Notch信号通路既可抑制肝癌细胞凋亡,又可促进肝癌细胞凋亡。Notch信号通路通过与其他细胞信号通路的“串扰”,或直接影响内外细胞凋亡途径,调控肝癌细胞凋亡。本文综述了上调或下调Notch信号通路促进肝癌细胞凋亡的最新研究结果,回顾了Notch信号通路在肝癌细胞凋亡途径中的不同作用机制,为肝癌的Notch信号通路靶向治疗提供理论支持。     

Notch信号通路在消化系肿瘤中的研究进展△

目的探讨Notch信号通路的结构特点、功能以及在消化系肿瘤中的研究进展。方法采用文献复习的方法,对研究Notch信号通路在消化系肿瘤分子机理的相关文献加以综述。结果Notch信号通路不仅在细胞正常发育、分化增殖和凋亡中起着重要的作用,而且与多种肿瘤的发生和发展具有相关性。结论对Notch信号通路进行合理的调控有可能为肿瘤的治疗开辟新的途径。     

中药调控Notch信号通路治疗骨质疏松症的研究

骨质疏松症（osteoporosis,OP）作为临床骨科方面常见的骨代谢性疾病，其发病原因主要是由于成骨细胞与破骨细胞共同介导的骨形成与骨吸收失去动态平衡关系所致，造成机体单位体积内的骨量减少、骨密度下降以及骨微结构改变，从而导致OP的发生和发展。机体内的骨代谢过程受多条信号传导通路的调控，神经源性位点缺口同源蛋白（Notch）信号通路作为重要的骨重建通路在调控与维持骨代谢稳定方面发挥着至关重要的作用，通过影响其通路蛋白的表达量，可以直接或间接地调控相关骨细胞的增殖、分化和凋亡，从而维持“骨平衡”的动态关系。近年来，运用中医药手段防治OP在临床上取得了良好的疗效，海内外学者对中药调控Notch信号通路防治OP的作用机制进行了多层次、多维度的探究，发现中药、Notch信号通路和OP三者之间存在明显的相关性。基于此，本文通过对中药单体及复方调控Notch信号通路防治OP的相关研究文献进行收集，整理、分析并总结目前的研究现状，以期为中药防治OP提供参考，为新药的研发和中医药特色诊疗方法的应用提供新的思路。     

Notch信号通路在脂肪源性间充质干细胞向血管内皮细胞分化中的作用研究进展

脂肪源性间充质干细胞(Adipose derived mesenchymal stem cells,ADMSC)具有干细胞的特性,能在体内及体外分化成血管内皮细胞并参与血管形成,在内皮细胞形成血管的过程中,血管内皮生长因子(vascular endothelial growth factor,VEGF)通过VEGF信号通路起着重要的调控作用,Notch信号通路是VEGF信号通路的下游通路,研究显示Notch信号通路在血管形成过程中发挥着至关重要的调控作用。本文对Notch信号通路在ADMSC向血管内皮细胞分化中的研究做一综述。     

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 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.     

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.     

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.     

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.     

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.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.