儿童实体瘤mdr1的进一步研究

多药耐药(multidrug resistance,MDR)是指肿瘤对多种结构不同的化疗药物有交叉耐药现象,是化疗失败的主要原因,多由mdr1基因产物P糖蛋白(P-glycoprotein,P-gp)介导.本实验对106例各类儿童实体瘤 mdr1 基因产物表达进行研究,进一步阐明mdr1基因表达情况,为临床术前术后化疗提供依据.     

IL-4基因修饰增强脑胶质瘤细胞毒性T淋巴细胞杀伤活性机制的探讨

目的 进一步探讨白细胞介素4（IL－4）基因修饰瘤苗增强细胞毒性T淋巴细胞（CTL）杀伤活性的机制。方法 通过逆转录病毒载体PL－IL－4－SN将人IL－4基因导入神经胶质瘤系SHG44细胞，以IL－4基因修饰瘤苗和野生型瘤细胞作刺激细胞诱导CTL反应，通过流式细胞仪检查瘤细胞表面分子的表达。结果 （1）IL－4基因修饰诱导瘤细胞表达MHC－Ⅱ类抗原、B7－1及ICAM－1等免疫刺激分子，对MHC－I类抗原表达无影响，其瘤苗诱导的CTL杀伤活性为野生型瘤细胞的7倍（P＜0．01）。（2）加入抗IL－4单抗可完全阻断IL－4诱导的细胞表面分子的表达，IL－4基因修饰瘤苗诱导CTL反应时培养上清可检测到大量IL－2的产生。抗IL－4或抗细胞表面分子单抗可降低IL－2产生及抑制CTL反应。结论 IL－4基因修饰可能是通过诱导MHC－Ⅱ类抗原等表面分子表达，促进IL－2的产生从而增强CTL杀伤活性。     

术前化疗对肾母细胞瘤瘤体的影响

目的　探讨术前化疗对肾母细胞瘤瘤体大小及瘤体耐药的影响。方法　本组 37例 ,术前影像学分期 ,Ⅰ～Ⅱ期 ,手术切除 ;Ⅲ～Ⅴ期 ,术前化疗 2～ 6周。免疫组化检测术后瘤体组织P 糖蛋白 (P glycoprotein ,P gp)、谷胱甘肽 硫转移酶 (glutathione s transferase π ,GST π)、拓扑异构酶Ⅱ(topoisomeraseⅡα ,TOPOⅡ )表达状况。结果　影像学分期 ,Ⅰ～Ⅱ期 2 0例 ,Ⅲ～Ⅴ期 17例。术前化疗组 ,瘤体缩减率 :1～ 2周为 (18.84± 3.5 4 ) %、3～ 4周为 (10 .78± 4 .2 6 ) %、5～ 6周为 (3.18±1.0 8) % ;瘤体GST π、TOPOⅡ表达阴性。瘤体在术前化疗 2周以内无P gp表达 ,4周以内有或弱阳性表达 ,4周以后P gp表达阳性。 结论　术前化疗应针对Ⅲ～Ⅴ期患儿 ,瘤体缩小主要集中于化疗 4周以内 ,超过 4周瘤体缩小不明显 ,且有引起肿瘤耐药的可能     

原发性肾病综合征患儿外周血单个核细胞多药耐药基因1及P-糖蛋白170的表达

目的检测原发性肾病综合征(PNS)患儿不同时间点外周血单个核细胞(PBMC)多药耐药基因1(MDR1)及其产物P-糖蛋白170(P-gp170)的表达,探讨MDR1及P-gp170在PNS患儿糖皮质激素(GC)耐药中的作用及介导耐药的可能机制。方法选择在苏州大学附属儿童医院住院的30例PNS患儿为研究对象,根据随访结果分为2组:激素耐药型肾病综合征(SRNS)组和激素敏感型肾病综合征(SSNS)组,每组各15例。选取10名健康体检儿童作为健康对照组。分3个时间点采集其外周血标本:发病初未用GC时,足量GC治疗4周后,病情缓解停用GC 2个月后或病情不缓解但泼尼松减量至<0.5 mg.kg-1.d-1时。采用反转录-聚合酶链反应(RT-PCR)检测PNS患儿不同时间点PBMC MDR1 mRNA的表达。流式细胞仪(FCM)检测PNS患儿不同时间点PBMC P-gp170的表达水平。结果健康对照组儿童和PNS患儿PBMC均有MDR1 mRNA及P-gp170表达。PBMC MDR1 mRNA与P-gp170的表达呈高度正相关(r=0.853,P<0.05)。SRNS组患儿3个时间点的PBMC MDR1 mRNA及...     

耐药基因蛋白在肿瘤组织血脑屏障的表达及临床意义

目的 通过检测多药耐药基因蛋白在儿童颅内肿瘤组织和正常脑组织的表达,探讨颅内肿瘤耐药机制.方法 采用免疫组织化学技术检测30例儿童颅内肿瘤和5例正常脑组织中P-糖蛋白(Pog]ycoproteln,P-gp)、多药耐药相关蛋白(muhidrug resistance-associated protein,MRP)、肺耐药相关蛋白(lung resistance-related protein,LRP)、DNA拓扑异构酶Ⅱ(topoisomerase Ⅱ,topo Ⅱ)和谷胱甘肽-S-转移酶(glutathione-s-transferase-л,GST-л)5种多药耐药基因蛋白表达强度和分布.结果 P-gp主要表达于毛细血管管壁和管周组织,而在肿瘤细胞表达较低.其他4种多药耐药基因蛋白在毛细血管管壁不表达.结论P-gp在血脑屏障中的神经胶质细胞终足部分参与了对化疗药物的阻滞.增加了颅内肿瘤的耐药性.     

槲皮素逆转K562、K562/ADM细胞耐药性研究

目的探讨槲皮素对K562、K562/ADM细胞热休克蛋白70信使核糖核酸(HSP70 mRNA)及多药耐药基因信使核糖核酸(MDR1 mRNA)表达的影响。方法采用MTT法检测槲皮素对K562细胞生长的抑制作用。逆转录聚合酶链反应(RT-PCR)检测多柔比星化疗前、后加入槲皮素K562细胞HSP70 mRNA及MDR1 mRNA的表达,及K562/ADM细胞在槲皮素作用后加多柔比星化疗两者的表达情况。结果1.槲皮素对K562细胞的生长抑制作用随浓度增加而增强。2.槲皮素作用后加多柔比星化疗组K562、K562/ADM细胞中HSP70 mRNA及MDR1 mRNA表达均显著降低。多柔比星化疗后加槲皮素组与多柔比星化疗组比较,K562细胞HSP70 mRNA、MDR1 mRNA表达均无显著性差异。结论槲皮素对白血病细胞生长具有抑制作用,并能下调HSP70 mR-NA及MDR1 mRNA表达。槲皮素能增加白血病细胞对多柔比星敏感性,逆转白血病细胞对多柔比星的耐药性。     

多源耐药基因表达水平的检测在儿童白血病中的临床意义

白血病是我国儿童恶性肿瘤中最多见的类型，尽管新的治疗手段有所应用，但化疗仍然是白血病的主要治疗方法，而影响化疗药物疗效的重要因之一是多源耐药（multidrug re－sistance）基因的高水平表达，其结果可以产生对多种结构、作用机制完全不同的药物同时耐药，因此对联合应用的化疗方案造成不良影响。多源耐药基因编码一个分子量为 170 kb的细胞膜糖蛋白（P一糖蛋白），在正常细胞中它是一个ATP依赖性的胞内脂质物质输出泵，起到转运胞内代谢产物的作用。抗肿瘤药物中：烷化剂类、植物碱类、抗肿瘤抗生素及激素类都是脂质（或亲脂疏水）性物质，多源耐药基因的蛋白质产物就是通过将这些药物泵出细胞而降低了药物在细胞内的浓度而使肿瘤细胞产生耐药性。我们应用逆转录PCR结合同位素定量分析，对 32例儿童白血病患者的多源耐药基因表达水平进行了研究。复发病人 MDR的表达里高水平（0． 474土 0． 087，P＜0． of），而初发病人未接受化疗者，MDR的表达则呈低水平（0． 157士0． 148），PMO． 05），缓解期病人的 MDR表达水平介于两者之间，该研究为探讨多源耐药基因表达水平与临床化疗之间的相关性及逆转克服多源耐药性药物的应用，提供了一定的理论依据。     

儿童颅内肿瘤5种多药耐药蛋白表达特点及临床意义

目的探讨肿瘤多药耐药蛋白P-糖蛋白(P-gp)、多药耐药相关蛋白1(MRP1)、肺耐药相关蛋白(LRP)、谷胱甘肽-S-转移酶(GST-π)及DNA拓扑异构酶Ⅱα(TopoⅡα)在儿童颅内肿瘤的表达特点,为其临床化疗方案的选择提供实验依据。方法分析本院2000年1月-2004年12月收治的临床资料完整、手术切除并经病理检查证实为儿童颅内肿瘤的石蜡标本38例,应用免疫组织化学S-P法检测38例颅内肿瘤儿童中多药耐药蛋白P-gp、MRP1、LRP、GST-π及TopoⅡα的表达;以10例非肿瘤患儿脑组织作为对照。结果1.颅内肿瘤患儿脑组织P-gp、GST-π、TopoⅡα、MRP1和LRP阳性表达率分别为65.8%、60.5%、47.4%、44.7%和44.7%,非肿瘤患儿脑组织P-gp阳性表达率为10%,其他4种多药耐药蛋白均为阴性。二组阳性表达率有显著性差异(P<0.01)。2.同一病理类型5种多药耐药蛋白的表达及同一耐药蛋白在不同病理类型间的表达均无显著性差异(Pa>0.05)。3.P-gp在星形细胞瘤和髓母细胞瘤的血管内皮细胞表达较高,而在颅咽管瘤和室管膜瘤组织则不明显。P-gp、GST-π在低恶性组和高恶性组间表达比较均有显著性差异(Pa<0.05)。结论儿童颅内肿瘤化疗失败的主要原因与血脑脊液屏障、血肿瘤屏障对化疗药物阻滞及肿瘤细胞本身的原发耐药密切相关。不同儿童颅内肿瘤的耐药性有各自的特点,有助于临床个体化化疗方案的制订。如果针对性地阻断这些耐药相关因素,能提高儿童颅内肿瘤的化疗效果。     

血管内皮生长因子反义核酸对细胞株HL60及耐药细胞株HL60/VCR的抑制作用

目的 探讨反义血管内皮生长因子(AS-VEGF)对HL60、耐药细胞株HLb0/VCR的影响及其机制,包括基因水平的耐药相关基因(Bcl-2,Mcl-1,MDRl,MRP,GSTπ,TopoⅡα,TopoⅡβ)和蛋白水平的耐药相关蛋白P糖蛋白(P-gp)表达量变化.方法 分子生物学方法构建AS-VEGF表达真核载体,通过脂质体转染技术将其转染至细胞株HL60和耐药细胞株HL30/VCR内,观察并绘制细胞生长曲线,ELISA法检测细胞培养上清VEGF表达量变化,RT-PCR法从mRNA水平检测细胞内耐药相关基因表达,蛋白质印迹方法从蛋白水平检测细胞表面p-gp表达.结果 1.25 mmoL/L的AS-VEGF真核表达载体转染HL60和HL30/VCR细胞株后继续培养24和48 h与未转染组比较均可明显抑制细胞生长,细胞生长减慢;转染组细胞48与24 h相比较VEGF、MDRI、MRP、GSTπ和TopoⅡβ的表达量均明显减少,Bcl-2、Mcl-1和TopoⅡα表达量则无明显变化;转染组HL60/VCR细胞表面p-gP表达量48与24 h相比较也明显减少.结论 AS-VEGF可通过抑制白血病细胞生长,改变细胞内的微环境和细胞膜相关蛋白转运通道,降低细胞解毒能力和自我修复能力逆转白血病细胞多药耐药.     

多药耐药基因转染脐血单个核细胞及其表达与功能的体外研究

目的：为克服白血病化疗中的骨髓抑制，采用含人多药耐药（MDR1）基因全长cDNA逆转录病毒载体转染入脐血单个核细胞，探索一种MDR1基因导入脐血造血细胞稳定、有效的方法，评价MDR1基因转染脐血细胞及其功能的表达，为体内转染MDR1基因保护骨髓免受大剂量化疗药物损伤提供条件。方法：采用含有MDR1基因表达质粒pHaMDR1/A的包装细胞PA317传代培养产病毒法，通过浓缩病毒上清液将MDR1基因导入人脐血单个核细胞，应用聚合酶链反应（PCR）方法、免疫组化法、流式细胞学等方法从基因、蛋白质、功能及细胞生物学特性等不同水平检测MDR1基因在脐血单个核细胞的表达、转染率及其与转染时间的关系和功能的表达；转染行为是否影响脐血细胞生物学特性。结果：（1）建立了一种安全可行、稳定高效的MDR1基因体外转染脐血造血细胞的体系和方法；（2）PCR方法证实外源性MDR1基因可有效性地体外整合到脐血单个核细胞中；（3）免疫组化法测得2日、4日、6日转染率分别为18.0%、29.8％、34.7%;(4)柔红霉素排出试验证实导入的MDR1基因表达产物P-gp有正常的生物学功能；（5）转染后的脐血细胞周期生物学特异性无异常。结论：MDR1基因体外转染脐血造血细胞是安全可行的，且在体外有稳定、有效的表达。这一方法为进一步在化疗骨髓保护的体内实验提供了有利的依据。     

Allergic factors associated with the development of asthma and the influence of cetirizine in a double-blind, randomised, placebo-controlled trial: First results of ETA®

There is a common progression known as the allergic march from atopic dermatitis to allergic asthma. Cetirizine has several antiallergic properties that suggest a potential effect on the development of airway inflammation and asthma in infants with atopic dermatitis. Methods. Over a two year period, 817 infants aged one to two years who suffered from atopic dermatitis and with a history of atopic disease in a parent or sibling were included in the ETAC^® (Early Treatment of the Atopic Child) trial, a multi-country, double-blind, randomised, placebo-controlled trial. The infants were treated for 18 months with either cetirizine (0.25mg/ kg b.i.d.) or placebo. The number of infants who developed asthma was compared between the two groups. Clinical and biological assessments including analysis of total and specific IgE antibodies were performed. Results. In the placebo group, the relative risk (RR) for developing asthma was elevated in patients with a raised level of total IgE (≥ 30 kU/I) or specific IgE (≥ 0.35 kUA/I) for grass pollen, house dust mite or cat dander (RR between 1.4 and 1.7). Compared to placebo, cetirizine significantly reduced the incidence of asthma for patients sensitised to grass pollen (RR = 0.5) or to house dust mite (RR = 0.6). However, in the population that included all infants with normal and elevated total or specific IgE (intention-to-treat - ITT), there was no difference between the numbers of infants developing asthma while receiving cetirizine or placebo. The adverse events profile was similar in the two treatment groups. Discussion. Raised total IgE level and raised specific IgE levels to grass pollen, house dust mite or cat dander were predictive of subsequent asthma. Cetirizine halved the number of patients developing asthma in the subgroups sensitised to grass pollen or house dust mite (i.e. 20% of the study population). In view of the proven safety of the drug, we propose this treatment as a primary pharmacological intervention strategy to prevent the development of asthma in specifically sensitised infants with atopic dermatitis.     

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孤独症谱系障碍(autistic-spectrum disorders,ASDs)近年来患病率逐年攀升至1%左右,其症状往往伴随终生,成为严重威胁儿童健康和发展的神经发育性疾患;注意缺陷多动障碍(attention deficit hyperactivity disorder,ADHD)是儿童期最常见的精神障碍,国内报道患病率为4.13%～5.83%,其症状可延续至青少年期,甚至到成年期[1]。这两类精神障碍在成年期的临床表现、共患病、治疗策略和预后与儿童期有哪些不同呢?本文通过回顾相     

EXCITING NEW TREATMENT APPROACHES FOR PATHYPHYSIOLOGIC MECHANISMS OF SICKLE CELL DISEASE

During the past several decades, our understanding of the complex pathophysiology of vasoocclusion associated with sickle cell disease has improved greatly. Interaction of genes, hemoglobin molecules, red cell membrane and metabolic changes, cell-cell interactions and cell-plasma interactions, red cell adhesion to vascular endothelium, activation of coagulation, and vascular reactivity play a role in vaso occlusion. Penicillin prophylaxis of pneumococcal infections and appropriate use of blood transfusions and other supportive measures improved survival of sickle cell patients. Hydroxyurea made a major impact on sickle cell therapy when it was shown to decrease acute painful episodes, acute chest syndrome, and the need for blood transfusion in adults. Significant experience in the use of hydroxyurea has been accumulated in older children. The benefits and risks of hydroxyurea for younger children and long-term risks in all patients will be evaluated in future investigations. Other promising therapies include butyrate compounds, clotrimazole, magnesium supplementation, poloxamer 188, antiadhesion agents, anticoagulant approaches, and nitric oxide. Hemopoietic transplantation remains the only curative therapy. However, several transgenic mouse models are available for studies of gene therapy or other treatment approaches on biochemical, cellular, and pathologic effects of mutant genes.     

Infiltrations of Epstein-Barr virus-carrying cells in granular lymphocyte-proliferative disorders corresponding to chronic active Epstein-Barr virus infection

A 21-year-old man with granular lymphocyte-proliferative disorders (GLPD) associated with chronic active Epstein-Barr virus (EBV) infection is described. Chromosomal analyses revealed several clonal abnormalities and two of them were mainly repetitious. High copy numbers of monoclonal EBV genome were also detected in the proliferative large granular lymphocytes (LGLs), indicating the monoclonal expansion of EBV-infected LGLs. The patient had an indolent course for several years, and there was no evidence of infiltrations of his bone marrow until the end stage. At autopsy, microscopic studies revealed marked infiltrations of LGL in the liver and spleen, and the infiltrating cells were NK-cell immunophenotype. The infiltrated LGLs showed latency I.     

LUTEINIZING HORMONE RECEPTOR MUTATIONS IN DISORDERS OF SEXUAL DEVELOPMENT AND CANCER

Human male sexual development is regulated by chorionic gonadotropin (CG) and luteinizing hormone (LH). Aberrant sexual development caused by both activating and inactivating mutations of the human luteinizing hormone receptor (LHR) have been described. All known activating mutations of the LHR are missense mutations caused by single base substitution. The most common activating mutation is the replacement of Asp-578 by Gly due to the substitution of A by G at nucleotide position 1733. All activating mutations are present in exon 11 which encodes the transmembrane domain of the receptor. Constitutive activity of the LHR causes LH releasing hormone-independent precocious puberty in boys and the autosomal dominant disorder familial male-limited precocious puberty (FMPP). Both germline and somatic activating mutations of the LHR have been found in patients with testicular tumors. Activating mutations have no effect on females. The molecular genetics of the inactivating mutations of the LHR are more variable and include single base substitution, partial gene deletion, and insertion. These mutations are not localized and are present in both the extracellular and transmembrane domain of the receptor. Inactivation of the LHR gives rise to the autosomal recessive disorder Leydig cell hypoplasia (LCH) and male hypogonadism or male pseudohermaphroditism. Severity of the clinical phenotype in LCH patients correlates with the amount of residual activity of the mutated receptor. Females are less affected by inactivating mutation of the LHR. Symptoms caused by homozygous inactivating mutation of the LHR include polycystic ovaries and primary amenorrhea.     

Resurgence of measles in Singapore: profile of hospital cases

OBJECTIVE: To ascertain the profile of cases of measles seen at a general hospital during a recent outbreak that occurred despite a measles vaccination program. METHODOLOGY: A retrospective study from January 1991 to March 1998. All patients with measles (ICD code 055. 9) seen at the emergency unit or as inpatients were included. RESULTS: There were 87 cases identified. The diagnosis was clinical in all and proven serologically in 71%. Eighty-five per cent of the cases occurred between January 1997 and March 1998. There was a bi-modal age distribution with peaks in the very young (相似文献   

Personality profiles and heart rate variability (vagal tone) in children with recurrent abdominal pain

The aim of the study was to explore psychological factors and autonomic activity in children with recurrent abdominal pain and to compare them with those in a control group of healthy children. The Personality Inventory for Children was used for assessment of developmental, emotional and psychosocial factors in 25 children with recurrent abdominal pain (age, 7-15 y). Parasympathetic and sympathetic functions in these children and in 23 healthy control subjects (age, 7-13 y) were also investigated, non-invasively using a computerized polygraph. Vagal tone (parasympathetic function) was indexed by calculation of respiratory sinus arrhythmia in beats/min. Skin conductance (sympathetic function) was recorded by the constant current method. On the Personality Inventory for Children, 16 patients had high scores on somatic concern. Several patients had scores in the clinical range for depression, withdrawal and anxiety, but the mean scores for these personality profile scales were well within the normal range of healthy children. Interestingly, there was a spike on the L (Lie)-scale for most of the patients and 15 patients had scores above or close to the clinical cut-off value. As compared with the scores in healthy children, vagal tone and sympathetic tone were normal. Conclusion: Many children with recurrent abdominal pain have scores in the clinical range for depression, withdrawal, anxiety and L-scale indicating coping problems, denial and a trend towards somatic concern that may contribute to the evolution of abdominal pain. Autonomic nerve activity was not disturbed in these children.     

Overcoming surfactant inhibition with polymers

Inhibition of the function of pulmonary surfactant in the alveolar space is an important element of the pathophysiology of many lung diseases, including meconium aspiration syndrome, pneumonia and acute respiratory distress syndrome. The known mechanisms by which surfactant dysfunction occurs are (a) competitive inhibition of phospholipid entry into the surface monolayer (e.g. by plasma proteins), and (b) infiltration and destabilization of the surface film by extraneous lipids (e.g. meconium-derived free fatty acids). Recent data suggest that addition of non-ionic polymers such as dextran and polyethylene glycol to surfactant mixtures may significantly improve resistance to inhibition. Polymers have been found to neutralize the effects of several different inhibitors, and can produce near-complete restoration of surfactant function. The anti-inhibitory properties of polymers, and their possible role as an adjunct to surfactant therapy, deserve further exploration.     

Understanding infant formula

The World Health organisation recommends breast feeding infants for the first six months of life. When this breast feeding does not occur either through parental choice or medical need, infant formulas will be required. There is a bewildering array of formulas on the UK market for many different requirements. When faced with an unsettled infant many parents (and healthcare professionals) will experiment with the infant formula available and then attend the paediatric clinic looking for help and advice. It is therefore essential that paediatricians understand what milks are available and what the key differences between different products are. This review attempts to provide a simple guide through many of the formulations currently available in the UK; and offers advice for the dietary management of the child with extra calorie requirements, infants with cow's milk protein allergy, gastro oesophageal reflux disease, apparent unresolved hunger and infantile colic. Whatever the underlying condition, there is likely to be an infant formula that is suitable in this generation of ever expanding formulations.