肿瘤相关巨噬细胞的研究进展

肿瘤相关巨噬细胞(tumor associated macro-phage,TAM)作为肿瘤微环境的重要组成部分,在多种恶性肿瘤发生、进展、侵袭和转移过程中起着重要作用,能明显促进肿瘤血管和淋巴管的生成,与患者的不良预后明显相关。本文就TAM的来源、TAM在肿瘤发生、进展和转移中的作用及TAM相关肿瘤靶向治疗进行综述,相信通过对TAM作用机制的深入研究可以为肿瘤治疗提供新的思路。1TAM与肿瘤微环境肿瘤的生物学特性不仅是由癌基因和抑癌基因表达调控,还依赖于肿瘤间质等构成的肿瘤微     

肺转移瘤的转移前微环境与转移微环境

一个多世纪前Paget就肿瘤器官特异性转移现象提出了“种子与土壤”学说。时下研究热点集中在一些特殊因子介导的靶器官环境改造,肿瘤细胞归巢行为。有动物实验证实肺转移瘤形成前,肺部已发生大量炎症因子聚集。宿主靶器官的改变影响转移瘤形成的每一个步骤。BethanPsaila与DavidLyden针对这一土壤变化过程提出转移前微环境（pre-metastaticniche）及转移微环境（metastaticniche）假说,指出土壤的变化是转移瘤形成的保障。该假说提出后迅速引起肿瘤研究界轰动。研究这一系列细胞分子生物学的改变,有助于阐明肿瘤转移这一复杂的过程,为转移干预带来新的思路。     

肝细胞癌异质性的研究进展

肝癌细胞与肿瘤微环境相互作用, 同时肝癌展示出时间异质性和空间异质性。本文就肝细胞癌的肿瘤微环境异质性与肿瘤异质性, 从肝细胞癌异质性特点、异质性产生机制以及肝细胞癌异质性对诊断和治疗的影响几个方面进行阐述, 为肝细胞癌的诊断治疗提供新的思考方向。     

肿瘤相关中性粒细胞在胃癌发生发展和治疗中的研究进展

迄今为止,胃癌的发病机制尚未完全明了。研究表明,肿瘤微环境（TME）对于肿瘤的发生和发展至关重要。TME中的肿瘤相关中性粒细胞（TANs）参与肿瘤进展的所有阶段,包括肿瘤起始、转移和免疫抑制,其复杂的作用机制增加了治疗胃癌的困难。随着对TME的深入研究,特异的治疗措施有望成为胃癌治疗的新希望。本文通过近年来文献回顾,研究和总结TANs在胃癌发生和转移中所起的作用,并阐述未来免疫治疗的发展方向,以期为临床和科研提供参考。     

胰腺癌干细胞研究进展

胰腺癌干细胞（PCSC）在胰腺癌的发生、发展过程中起着重要作用,且与胰腺癌的耐药、转移机制关系密切。PCSC的表面标志物、分离、鉴定、信号通路、微环境、耐药、转移和靶向治疗等方面的研究,将为临床胰腺癌的治疗提供新的方向。     

肿瘤微环境中微生物的研究进展

大量研究已证明肠道微生物对肿瘤生物学有着多种影响, 已成为肿瘤发生和对癌症治疗反应的生物标志物和调节剂。然而, 目前对疾病相关微生物的了解很大程度上仅限于肠道微生物。近年来, 肿瘤组织中微生物的研究正处于快速发展阶段, 新的证据表明, 肿瘤内微生物群是肿瘤微环境的重要组成部分。肿瘤微环境中微生物群可能直接调节癌症的发生, 进展和对化学或免疫疗法的反应。这些发现不仅为肿瘤生物学提供了新的机制见解, 而且未来还可能成为肿瘤预防和治疗的新方向。本综述的目的主要是讨论肿瘤微环境中微生物在肿瘤发生发展、诊断和治疗中的作用。     

阴茎癌的免疫微环境及免疫治疗的研究进展

阴茎癌是一种较为罕见的肿瘤。早期患者预后较好,治疗方案多选择单纯的手术治疗。但发生盆腔转移及远处转移患者的5年生存率低于10%,对于这部分局部晚期及转移性患者需要联合治疗。随着多组学、免疫微环境和免疫治疗研究取得突破性进展,为阴茎癌的治疗提供了新的治疗思路。本文概述了阴茎癌的免疫微环境研究进展及目前免疫治疗策略的可行性。     

肿瘤干细胞微生景的耐药性及相关靶向治疗

肿瘤干细胞是近年来在许多肿瘤组织中发现的一类特殊干细胞,具有自我更新和分化的能力,可通过不断分化为肿瘤细胞,从而形成肿瘤原发灶和转移灶.肿瘤干细胞对化疗和放疗具有很强的不敏感性,这一特性主要与其微生景中的各种分子及其相互调控有关.目前一些新型的治疗策略是针对肿瘤干细胞及其微环境所研发的新的靶向治疗方法,如抑制新生血管形成、阻止细胞发生上皮一间质转化等.深入研究肿瘤干细胞及其微生景的耐药性,可为肿瘤治疗提供新途径.     

microRNA调控肿瘤微环境的研究进展

目的总结micro RNA对肿瘤微环境的调控机制。方法通过检索Pub Med获取近年来关于micro RNA对肿瘤细胞微环境调控机制的相关文献资料并进行综述。结果 micro RNA可以参与低氧诱导因子、肿瘤相关成纤维细胞、细胞外基质等肿瘤微环境因素在转录后水平表达的调控,微环境的变化会导致肿瘤细胞生物学行为的改变。结论 micro RNA参与调节肿瘤微环境的诸多因素,而微环境的改变对于肿瘤的发生、发展有着至关重要的作用,明确micro RNA对微环境调控的机制不仅有助于探索肿瘤细胞生物学行为,同样为肿瘤疾病的诊断和预后提供新的思路。     

肿瘤干细胞对恶性肿瘤诊治的意义

恶性肿瘤严重地威胁着人类的健康.多药耐药现象增加了其治疗难度,局部复发和远处转移最终导致了治疗失败,然而遗憾的是机制尚不清楚.研究发现在肿瘤组织中有一个具有自我更新及分化潜能的的细胞亚群,是复发及转移的根源.这部分细胞被称为肿瘤干细胞.随后,人们相继从血液系统肿瘤及多种实体瘤中分离、鉴定了肿瘤干细胞.随着肿瘤干细胞学说的提出及确认,人们对肿瘤的复发、转移及多药耐药现象有了新的认识,从而为恶性肿瘤的治疗及复发转移的预防提供了一个全新的线索.本文就此进行综述.     

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.     

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.     

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.