白细胞介素4基因修饰抗白血病效应的体外研究

目的　观察白细胞介素 4(IL 4)基因修饰对白血病细胞株HL 6 0和K5 6 2生长及其诱导的T淋巴细胞功能的影响。方法　采用逆转录病毒载体pLXSN将IL 4基因导入上述细胞株。以野生型和载体修饰的相应细胞为对照 ,检测了IL 4基因修饰HL 6 0和K5 6 2细胞 (每株细胞检测 12孔 )的增殖、死亡特性及其诱导的T淋巴细胞增殖反应 ;用逆转录聚合酶链反应技术 (RT PCR)检测T淋巴细胞产生IL 2、IL 6和干扰素γ(IFN γ) ;用 51铬 ( 51Cr)释放法检测淋巴杀伤细胞活性。结果　HL 6 0和K5 6 2表达IL 4的最高水平可达 6 5 .4pg/ ( 10 6细胞·2 4h)和 10 6 .6pg/ ( 10 6细胞·2 4h) ,IL 4基因修饰的HL 6 0和K5 6 2细胞增殖反应明显受抑制 ,K5 6 2培养过程中死亡细胞增多 ;白血病细胞所诱导的T淋巴细胞增殖反应 ,产生细胞因子能力及细胞毒性T细胞 (CTL)杀伤活性均明显高于对照组。结论　IL 4基因修饰不仅可直接抑制HL 6 0、K5 6 2细胞的生长 ,而且可能通过促进T淋巴细胞功能及CTL杀伤活性控制其生长。     

白细胞介素—4基因修饰Raji细胞促进肿瘤特异细胞毒性T细胞杀？…

探讨人白细胞介素－４基因修饰对伯基特淋巴瘤细胞株－Ｒａｊｉ的体外生物学特性，肿瘤特异性细胞毒性Ｔ细胞杀伤活性的影响及其机制。结论外源性ＩＬ－４基因表达产物可能和于瘤细胞和ＰＢＭＣ，通过诱导ＩＬ－２，ＩＦＮ－γ等细胞因子促进ＣＴＬ反应，并增强其杀伤活性。     

细胞毒性T淋巴细胞抗病毒感染作用机制的研究进展

人类及其他动物细胞经常受到病毒感染的威胁,故能够有效的发现并清除受感染的细胞对维持器官及组织的正常功能非常重要。虽然自然杀伤细胞和活化的巨噬细胞有杀伤靶细胞的作用,但破坏病毒感染的靶细胞主要靠细胞毒性T淋巴细胞（CTL）,CTL是执行细胞免疫、排斥同种异体移植物、杀伤病毒感染细胞和肿瘤细胞的效应细胞。CTL是一类具有CD^8＋表面标志、受主要组织相容性抗原I（MHCI）类分子限制的具有杀伤功能的T细胞。CTL介导的靶细胞杀伤的特点是：杀伤受T细胞受体（TCR）以及MHCI类分子的严格限制,且对靶细胞的杀伤具有特异性、程序性和快速性。本文对CTL抗病毒感染作用机制方面的研究作一综述。     

白介素-4基因修饰对儿童肝母细胞瘤多药耐药的逆转及其机制研究

目的探讨白介素-4(IL-4)基因修饰对儿童实体瘤多药耐药(MDR)的逆转作用及可能机制.方法用逆转录病毒载体将人IL-4基因导入人肝母细胞瘤细胞系HepG2,采用MTT生物活性法检测瘤细胞对化疗药物的敏感性.间接免疫荧光分光光度分析瘤细胞P-糖蛋白(P-gp)的表达率.微量荧光分光光度法分析瘤细胞内阿霉素(ADM)聚集量.结果 IL-4基因修饰显著降低瘤细胞对种化疗药物的半数抑制浓度(IC50),表现出MDR逆转效应(耐药逆转倍数在6～32倍数间)及明显增加化疗药物在瘤细胞内聚集,同时IL-4基因修饰瘤细胞P-gp阳性表达率(5±0.6%)较野生型及空载体修饰细胞(98.5±0.5%、97.0±1.0%)明显减低.IL-4基因修饰对瘤细胞的MDR逆转作用可为PKC激活剂TPA所阻断.IL-4基因修饰瘤苗及其培养上清与野生型细胞共培养,也可使野生型瘤细胞产生MDR逆转效应.结论 IL-4 基因修饰瘤苗可通过自分泌、旁分泌形式逆转瘤细胞MDR,此作用可能与其抑制PKC活性及下调P-gp表达.     

白细胞介素-4基因修饰Raji细胞促进肿瘤特异细胞毒性T细胞杀伤活性

目的探讨人白细胞介素（ＩＬ）４基因修饰对伯基特淋巴瘤细胞株———Ｒａｊｉ的体外生物学特性、肿瘤特异性细胞毒性Ｔ细胞（ＣＴＬ）杀伤活性的影响及其机制。方法采用逆转录病毒介导基因转染法将人ＩＬ４ｃＤＮＡ导入Ｒａｊｉ株并筛选获得高效价表达ＩＬ４的克隆,观察ＩＬ４表达克隆形态学特征、体外增殖反应及其诱导的外周血单个核细胞（ＰＢＭＣ）增殖反应和ＩＬ２、干扰素（ＩＦＮ）γ基因表达及ＣＴＬ杀伤活性。结果ＩＬ４基因修饰对Ｒａｊｉ的体外生物学特性无明显影响,但明显促进正常人ＰＢＭＣ增殖及ＩＬ２、ＩＦＮγ基因表达,其诱导建立的ＣＴＬ杀伤活性明显增强,效应细胞：靶细胞比例为３０∶１时,ＩＬ４基因修饰可使Ｒａｊｉ细胞诱导的ＣＴＬ杀伤活性上升２～３倍。结论外源性ＩＬ４基因表达产物可能作用于瘤细胞和（或）ＰＢＭＣ,通过诱导ＩＬ２、ＩＦＮγ等细胞因子促进ＣＴＬ反应,并增强其杀伤活性。     

白细胞介素12与感染性疾病

白细胞介素12（IL－12）是异二聚体细胞因子（CK），主要由抗原递呈细胞（APCs）产生，在介导对原虫、胞内菌、真菌、病毒等病原的细胞免疫中起主要作用，其作用包括：诱导静止及活化的天然杀伤细胞（NK）及T细胞产生γ干扰素（γ－IFN）；促进NK及T细胞的增殖；增强NK的细胞毒作用；促使细胞毒T淋巴细胞（CTL）的成熟。IL－12是感。染性疾病的早期先天免疫及后期特异免疫的桥梁，它的产生在CK网络中受到正负反馈机制的调节。宿主防御各种感染的过程中，IL－12起保护作用的同时于某些疾病状态下也有不利作用。因此，IL－12很有希望应用于适当条件下各种人类感染性疾病的防治。     

CⅡTA锤头状核酶抑制Jukart细胞MHCⅡ类抗原的表达

目的　针对同种异体细胞移植的免疫反应主要是由主要组织相容性复合物Ⅱ (majorhistocompatibilitycomplex ,MHC Ⅱ ,人类中亦称HLA Ⅱ )类抗原介导 ,而MHCⅡ类分子转录激活因子 (MHCclassⅡtransactivator ,CⅡTA)对MHCⅡ分子的表达起严格且专一性的调控作用 ,拟通过抗CⅡTA锤头状核酶 (ribozyme,Rz)抑制细胞表面MHCⅡ分子的表达。 方法　设计并合成针对人类CⅡTA基因第 134、2 18、4 6 4位点的一组核酶 ,分别命名为Rz134、Rz2 18、Rz4 6 4。通过体外制备和活性鉴定 ,筛选出活性较高的核酶———Rz4 6 4。将Rz4 6 4克隆到含有核糖体内进入位点及增强型绿色荧光蛋白的表达载体 (internalribosomeentrysite enhancedgreenfluorescentprotein ,pIRES2 EGFP) ,简称为 pRz4 6 4 ,并稳定转染Jukart细胞株 (pRz4 6 4 J) ,流式细胞术检测经典的MHCⅡ (HLA DR、DP、DQ)抗原表达 ,逆转录 聚合酶链反应 (RT PCR)检测CⅡTAmRNA水平。结果　pRz4 6 4 J与无关核酶组比较 ,HLA DR、DP、DQ抗原诱导型表达分别降低了 73 2 7%、88 93%、5 8 82 % ;同时CⅡTA的诱导性mRNA含量明显减少 (P <0 0 1)。结论　抗CⅡTA锤头状核酶可抑制CⅡ ATmRNA的表达 ,从而阻止其调控的相应基因———MHCⅡ分子的表达 ,为进一步探讨免疫     

新生儿缺氧缺血性脑病T细胞活化受抑的机制探讨

目的：研究轻、中、重度缺氧缺血性脑病（HIE）新生儿T细胞功能增殖和活化功能状态及可能机制。方法：分HIE新生儿组（60例）及健康新生儿组，采用尼龙毛法分离两组外周血单个核细胞中的T细胞；用CTLL－2细胞株活性检测测定T细胞培养上清中IL－2活性；流式细胞仪间接免疫荧光法检测T细胞表面白细胞介素2受体α（IL－2Rα）表达，3H－TdR掺入法测定T淋巴细胞增殖反应。放射免疫分析法测定T细胞内环磷酸腺苷（cAMP)，环磷酸鸟苷（cGMP)。结果：中、重度HIE患儿T细胞功能明显受抑，T细胞转化率及T细胞IL－2及IL－2R的表达下降（P均＜0．05），其活化T细胞内cAMP含量升高，cGMP含量降低，此变化与T细胞IL－2及IL－2R的表达下降（P均＜0．05），其活化T细胞内cAMP含量升高，cGMP含量降低，此变化与T细胞功能受抑密切相关。结论：新生儿HIE是T细胞功能不同程度受抑，可能与胞内环核苷酸代谢系统信号传导途径有关。     

白细胞纱4基因修饰抗白血病效应的体外研究

目的 观察白细胞介素４（ＩＬ－４）基因修饰对白血病细胞株ＨＬ－６０和Ｋ５６２生长及其诱导的Ｔ淋巴细胞功能的影响。方法 采用逆转录病毒载体ｐＬＸＳＮ将ＩＬ－４基因导入上述细胞株,以野生型和载体修饰的相应细胞为对照,检测了ＩＬ－４基因修饰ＨＬ－６０和Ｋ５６２细胞（每株细胞检测１２孔）的增殖、死亡特性及其诱导的Ｔ淋巴细胞增殖反应;用逆转录聚合酶链反应技术（ＲＴ－ＰＣＲ）检测Ｔ淋巴细胞产生ＩＬ－２、ＩＬ－     

自体移植物抗宿主病

自体造血干细胞移植（ａｕｔｏＨＳＣＴ）后应用小剂量短疗程环孢菌素Ａ（ＣｓＡ）（１ｍｇ／ｋｇ·ｄ，共２８天），可在６０％～７５％的病例中诱导产生自体移植物抗宿主病（ａｕｔｏＧＶＨＤ）。在此过程中，胸腺发挥着重要作用。该病的效应细胞大多是能识别主要组织相容性复合体（ＭＨＣ）Ⅱ类抗原（小鼠为Ⅰ区相关抗原，即Ⅰａ）的Ｔ细胞受体（ＴＣＲ）α、β＋ＣＤ８＋细胞毒性Ｔ淋巴细胞，也有少数为ＣＤ４＋细胞毒性Ｔ淋巴细胞，ＭＨＣⅡＣＬＩＰ复合物可能是该效应细胞的靶抗原。初步研究表明，ＣｓＡ诱导的ａｕｔｏＧＶＨＤ具有强大的抗瘤作用。其抗瘤作用的强弱与ＧＶＨＤ的严重程度及瘤细胞表面ＭＨＣⅡ类抗原的表达有关。ＣｓＡ与干扰素（ＩＦＮ）、白细胞介素２（ＩＬ２）合用可增强ａｕｔｏＧＶＨＤ的抗瘤作用。这项研究为防止ａｕｔｏＨＳＣＴ后肿瘤的复发开辟了一个新途径     

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.