肿瘤干细胞与骨肉瘤相关研究进展

肿瘤研究中发现极少数有分化潜能,可无限增殖的亚细胞群具有干细胞特性,肿瘤的发生、生长、转移与之密切相关.肿瘤干细胞主要来源于成体干细胞,也可来源于祖细胞、分化细胞或骨髓细胞.白血病、乳腺癌、恶性脑瘤存在肿瘤干细胞已经明确,在前列腺癌、肺腺癌、肝癌、恶性黑色素瘤等多种肿瘤中也已初步分离出相应的肿瘤干细胞.骨肉瘤是常见的骨组织恶性肿瘤,肿瘤干细胞学说可更好地解释骨肉瘤恶性程度高、转移早、抗化疗等特性.应用无血清悬浮培养方法,干细胞样骨肉瘤细胞已初步得以分离、分析.该文就肿瘤干细胞及干细胞样骨肉瘤细胞的相关研究进展作一综述.     

肝干细胞与肝癌干细胞相关研究进展

肿瘤是一种干细胞疾病,这一理论目前得到广泛认可,越来越多的研究也显示了干细胞与肝癌发生间的密切关系。肝癌恶性程度高,疗效差,研究干细胞在肝癌中的作用有望从根本上改变肝癌的诊疗方法和疗效。本文就干细胞在肝癌中的相关研究进展作一综述。     

骨髓间充质干细胞对肝癌影响作用的研究进展

肝癌术后患者常因肝脏组织代偿和恢复功能受限,术后急性肝衰竭的发病率及病死率较高.骨髓间充质干细胞可以在肝脏微环境下直接分化为新的肝细胞,通过分泌营养因子促进组织修复、参与免疫调节、抗纤维化和抑制肝星状细胞和肝原细胞的活性等,对肝损伤及肝功能不全具有较好的疗效.然而骨髓间充质干细胞同时具有致瘤性和促进肿瘤生长的作用.利用骨髓间充质干细胞预防和治疗肝癌术后肝衰竭的发生是否安全可靠,这是目前研究的热点问题.本文就骨髓间充质干细胞对于原发性肝癌影响作用的研究进展进行综述,以期为干细胞的临床应用提供理论基础.     

肿瘤干细胞和肿瘤

肿瘤干细胞(cancer stem cell,CSC)近几年来成为肿瘤研究的新的热点,尽管越来越多的肿瘤干细胞亚群被鉴定出来,但是肿瘤干细胞的细胞表面标记物并不唯一,这町能是因为肿瘤干细胞的来源不一造成的.肿瘤干细胞在肿瘤迁移中扮演着重要角色.肿瘤干细胞发生上皮细胞间质转化(epithelial-mesenchymal-transition,EMT)后获取较强的迁移能力,随着血液循环在转移灶停留,并与组织细胞和骨髓源间质细胞-同形成适应肿瘤转移灶形成的微环境,最终形成肿瘤转移.     

肿瘤干细胞和肿瘤

肿瘤干细胞(cancer stem cell,CSC)近几年来成为肿瘤研究的新的热点,尽管越来越多的肿瘤干细胞亚群被鉴定出来,但是肿瘤干细胞的细胞表面标记物并不唯一,这町能是因为肿瘤干细胞的来源不一造成的.肿瘤干细胞在肿瘤迁移中扮演着重要角色.肿瘤干细胞发生上皮细胞间质转化(epithelial-mesenchymal-transition,EMT)后获取较强的迁移能力,随着血液循环在转移灶停留,并与组织细胞和骨髓源间质细胞-同形成适应肿瘤转移灶形成的微环境,最终形成肿瘤转移.     

DNA甲基化与肝细胞癌

肝细胞癌是原发性肝癌的主要类型,也是常见的恶性肿瘤之一,具有较高的发病率和病死率。然而在分子和细胞水平,肝癌的发病机制仍然不清楚。一般来说,肿瘤形成通常被认为是抑癌基因失活或原癌基因激活致DNA突变而诱导人类正常细胞向恶性细胞转化的过程。近年来随着对肿瘤研究的不断深入,人们发现表观遗传学改变与肝癌发生发展密切相关。其中DNA甲基化是人类基因组发生最为常见的一种表观遗传学事件,也是表观遗传学研究最为深入的一种机制。本文将就DNA甲基化在肝癌中的研究进展作一综述。     

肿瘤相关间充质干细胞的研究进展

间充质干细胞普遍存在于组织间质中，对组织损伤修复、机体免疫调控等均发挥重要作用。近年研究发现，肿瘤组织中普遍存在间充质干细胞，称为肿瘤相关间充质干细胞，且与正常组织内的间充质干细胞在调控功能、基因表型等方面有所区别。可以说，肿瘤相关间充质干细胞是独立于正常间充质干细胞的特殊亚型。本文对肿瘤相关间充质干细胞的来源、转化、功能及其临床价值进行综述。     

机遇性肝脏肿瘤的外科处理

机遇性肝脏肿瘤是指由医学影像技术意外发现的一组肝脏占位性病变。本文报告31例机遇性肝脏肿瘤。其中肝血管瘤19例,原发性肝癌7例,其它少见肝脏病变5例。根据病变的性质,可将机遇性肝脏肿瘤分为完全良性(64.5％)、恶性((22.6％)及具有潜在恶变(12.9％)三大类。我们认为详细的病史追询和体格检查、影像检查及甲胎蛋白测定对本病的进一步诊断具有重要价值,并提出机遇性肝脏肿瘤的手术治疗原则。     

肝肿瘤干细胞的研究进展

肿瘤干细胞是一群存在于某些肿瘤组织中的干细胞样细胞。笔者就肝肿瘤干细胞的来源、与肝癌的关系、分离鉴别等问题的研究进展作一综述。     

肿瘤相关巨噬细胞与肝癌的研究进展

慢性炎性介质反应与肿瘤发生也发展密切相关,肿瘤相关巨噬细胞作为肿瘤免疫微环境中最丰富的免疫细胞,在连接慢性炎性介质反应与肿瘤之间发挥重要的桥梁作用.大多数肿瘤相关巨噬细胞表型和功能倾向于M2型巨噬细胞,并被认为是肿瘤患者预后不良的重要标志.我国肝癌患者大多伴有长期慢性病毒感染,肝脏中大量巨噬细胞在长期慢性炎性介质反应浸润刺激下可通过多种途径促进肝癌发生、发展.本文就肿瘤相关巨噬细胞与肝癌发生、发展作一综述.     

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.     

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.     

The analgesic effect of racemic ketamine in patients with chronic ischemic pain due to lower extremity arteriosclerosis obliterans

Background : Ketamine in sub-dissociative doses has been shown to have analgesic and phantom-Limb pain, where conventional treatment has often failed. Chronic ischemic pain due to lower extremity arteriosclerosis obliterans often responds poorly to analgesics, and the pain-generating mechanisms are not well understood.
Methods : Eight patients with rest pain in the lower extremity due to arteriosclerosis obliterans were given sub-dissociative doses of 0.15, 0.30, or 0.45 mg/kg racemic ketamine and morphine 10 mg as a 5-min infusion on four separate days in a cross-over, double-blind, randomised protocol. Plasma levels of (S)- and (R)-ketamine and their nor-metabolites were analysed with an enantioselective high-performance liquid chromatography (HPLC) method. Pain levels were evaluated with a visual analogue scale (VAS).
Results : Individual pain levels were highly variable during and after all the infusions but the pooled pain levels showed a dose-dependent analgesic effect of ketamine with a transient but complete pain relief in all patients at the highest dose (0.45 mg/ kg). Side-effects, mainly disturbed cognition and perception, were pronounced and dose-dependent. Morphine 10 mg had an analgesic peak at 20 min and 5/8 patients had complete pain relief. The remaining 3 patients also had high baseline pain scores, indicating a higher analgesic potency for the 0.30 and 0.45 mg/ kg ketamine doses than for morphine 10 mg.
Conclusion : We have demonstrated a potent dose-dependent analgesic effect of racemic ketamine in clinical ischemic pain. Due to a narrow therapeutic window, this analgesic effect is probably best utilised in combination with other analgesics.     

Intravenous endotoxin does not increase tissue extravasation of albumin in rats

Background : It is unclear whether activation of the inducible nitric oxide synthase (iNOS) increases or decreases the extravasation of plasma.
Methods : Chloralose anaesthetised male Wistar rats received E. coli lipopolysacharide (LPS), 3 mg kg^-1 i.v., or the corresponding volume of saline, 3 or 5 h before the end of the experiment. Mean arterial pressure (MAP) and heart rate (HR) were recorded. Tissue clearance of radio-labelled albumin, during the last 2 h of each experiment, was determined by a double-isotope method. In separate animals, the serum concentration of nitrite and nitrate was determined, 5 h after LPS or the solvent.
Main Results : LPS initially decreased MAP and lastingly increased HR. In the 3-h LPS animals (n=8), tissue plasma clearance was lower in the heart and calf muscle and increased only in diaphragm, compared to corresponding control animals (n=8). In the 5-h LPS rats, clearance was lowered (n=8) in the entire gastrointestinal tract and in testes, compared to controls (n=8). The serum nitrite/nitrate concentration was higher in animals given LPS (n=6) than in controls (n=6).
Conclusion : After LPS, tissue clearance of albumin was not increased in any major tissue, in spite of increased serum levels of NO end products. Apparently, after activation of iNOS, the augmented release of NO is not necessarily associated with increased albumin extravasation.     

Adrenaline markedly improves thoracic epidural analgesia produced by a low-dose infusion of bupivacaine, fentanyl and adrenaline after major surgery: A randomised, double-blind, cross-over study with and without adrenaline

Background: Basic pharmacological research indicates that there are synergistic antinociceptive effects at the spinal cord level between adrenaline, fentanyl and bupivacaine. Our clinical experience with such a mixture in a thoracic epidural infusion after major surgery confirms this. The objectives of the present study were to evaluate the effects on postoperative pain intensity, pain relief and side effects when removing adrenaline from this triple epidural mixture. Methods: A prospective, randomised, double-blind, cross-over study was carried out in 24 patients after major thoracic or abdominal surgery. Patients with only mild pain when coughing during a titrated thoracic epidural infusion of about 10 ml · h^?1 of bupivacaine 1 mg · ml^?1, fentanyl 2 μg · ml^?1, and adrenaline 2 μg · ml^?1 were included. On the 1^st and 2^nd postoperative days each patient was given a double-blind epidural infusion, at the same rate, with or without adrenaline. The effect was observed for 4 h or until pain when coughing became unacceptable in spite of a rescue analgesic procedure. Rescue analgesia consisted of up to two epidural bolus injections per hour and i.v. morphine if necessary. All patients received rectal paracetamol 1 g, every 8 h. Fentanyl serum concentrations were measured with a radioimmunoassay technique at the start and end of each study period. Main outcome measures were extent of sensory blockade and pain intensity at rest and when coughing, evaluated by a visual analogue scale, a verbal categorical rating scale, the Prince Henry Hospital pain score, and an overall quality of pain relief score. Results: The number of hypaesthetic dermatomal segments decreased (P <0.001) and pain intensity at rest and when coughing increased (P <0.001) when adrenaline was omitted from the triple epidural mixture. This change started within the first hour after removing adrenaline. After 3 h pain intensity when coughing had increased to unacceptable levels in spite of rescue analgesia (epidural bolus injections and i.v. morphine). Within 15–20 min after restarting the triple epidural mixture with adrenaline, pain intensity was again reduced to mild pain when coughing. Serum concentration of fentanyl doubled from 0.22 to 0.45 ng · ml^?1 (P <0.01), and there was more sedation during the period without adrenaline. Conclusions: Adrenaline increases sensory block and improves the pain-relieving effect of a mixture of bupivacaine and fentanyl infused epidurally at a thoracic level after major thoracic or abdominal surgery. Serum fentanyl concentrations doubled and sedation increased when adrenaline was removed from the epidural infusion, indicating more rapid vascular absorption and systemic effects of fentanyl.     

Reduction of Plasma Fibrinogen, Immunoglobulin G, and Immunoglobulin M Concentrations by Immunoadsorption Therapy with Tryptophan and Phenylalanine Adsorbents

Abstract Immunoadsorption (1A) therapy with tryptophan (TR-350) or phenylalanine (PH-350) adsorbents has been used to reduce the concentration of serum antibodies in human lymphocyte antigen (HLA)-immunized patients. Other forms of plasma purification have been reported to reduce the level of fibrinogen, which affects the blood properties. In this study we investigated the effects of IA therapy using both adsorbents on plasma fibrinogen and immunoglobulins G and M in 13 patients (8 patients were treated with TR-350, and 5 patients were treated with PH-350). During each session 1 plasma volume (2.8 ± 0.4 L of plasma) was processed through the immunocolumn and then returned to the patient together with the blood cells. Compared with the pretreatment values, the plasma fibrinogen, IgG, and IgM concentrations were significantly reduced after IA therapy (p < 0.01 for TR-350; p < 0.04 for PH-350). There was a positive correlation between the degree of reduction of plasma proteins and the number of IA treatments given. A nonpara-metric test (Wilcoxon's signed-rank test or the Mann-Whitney test) was used for statistical analysis. We conclude from our study that IA therapy effectively lowers the plasma levels of fibrinogen, IgG, and IgM and thus can be considered a valuable alternative to other blood purification methods.     

Utilisation des médicaments prokinétiques en réanimation : indications et limites ?

Enteral feeding is often limited by gastric and intestinal motility disturbances in critically ill patients, particularly in patients with shock. So, promotility agents are frequently used to improve tolerance to enteral nutrition. This review summaries the pathophysiology, presents the available pharmacological strategies, the clinical data, the counter-indications and the principal limits. The clinical data are poor. No study demonstrates a positive effect on clinical outcomes. Metoclopramide and erythromycin seems to be the more effective. Considering the risk of antibiotic resistance, the first line use of erythromycin should be avoided in favor of metoclopramide.     

Anesthésie générale chez l’enfant : quid des pratiques en 2010 ?

Introduction

The practice of pediatric anesthesia requires a regular update of scientific knowledge and technical skills. To provide the most adequate Continuing Medical Education programs, it is necessary to assess the practices of pediatric anesthesiologists. Thus, the objective of this survey was to draw a picture of the current clinical practices of general anesthesia in children, in France.

Material and methods

One thousand one hundred and fifty questionnaires were given to anesthesiologists involved in pediatric cases. These questionnaires collected information on various aspects of clinical practice relative to induction, maintenance, recovery from general anaesthesia and also classical debated points such as children with Upper Respiratory Infection (URI), emergence agitation, epileptoid signs or anaesthetic management of adenoidectomy. Differences in practices between CHG (general hospital), CHU (teaching hospital), LIBERAL (private) and PSPH (semi-private) hospitals were investigated.

Results

There were 1025 questionnaires completed. Fifty-five percent of responders worked in public hospitals (CHG and CHU); 77% had a practice that was 25% or less of pediatric cases. In children from 3 to 10 years: 72% of respondents used always premedication and two thirds performed inhalation induction in more than 50% of cases. For induction, 53% used sevoflurane (SEVO) at 7 or 8%. Respondents from LIBERAL used higher SEVO concentrations. Tracheal intubation was performed with SEVO alone (37%), SEVO and propofol (55%) and SEVO with myorelaxant (8%), 93% of respondents used a bolus of opioid. For maintenance, the majority of respondents used SEVO associated with sufentanil; desflurane and remifentanil were more frequently used in CHU. Two thirds of respondents used N₂O. Depth of anesthesia was commonly assessed by hemodynamic changes (52%), end tidal concentration of halogenated (38%) or automated devices based on EEG (7%). In children with URI, 98% of respondents used SEVO for anesthesia. To control the airway 42% used a tracheal tube, 30% a laryngeal mask and 20% a facial mask. Emergence agitation was an important concern for two thirds of respondents, while epileptoid signs were considered as important by only 20%. Eighty-nine percent of respondents practiced anesthesia for adenoidectomy. Anesthesia was induced by inhalation of SEVO 7–8% (41%), 6% (39%) or 4% (12%), 66% put an intravenous line (less frequently in LIBERAL). 67% of the responders managed adenoidectomy without any device to control the airway (more frequently in LIBERAL), 32% administrated a bolus of opioid (less frequently in LIBERAL).

Discussion

This survey demonstrated that the practices regarding general anesthesia in children are relatively homogenous. Most of the differences appeared between LIBERAL and the others structures; the anaesthetic management for adenoidectomy illustrates these findings.     

Intérêt d’une rééducation précoce pour les patients neurologiques

Rehabilitation improves the functional prognosis of patients after a neurologic lesion, and tendency is to begin rehabilitation as soon as possible. This review focuses on the interest and the feasibility of very early rehabilitation, initiated from critical care units. It is necessary to precisely assess patients’ impairments and disabilities in order to define rehabilitation objectives. Valid and simple tools must support this evaluation. Rehabilitation will be directed to preventing decubitus complications and active rehabilitation. The sooner rehabilitation is started; the better functional prognosis seems to be.