铁剥夺诱导HL-60细胞凋亡及对化疗药物诱导HL-60细胞凋亡的影响

目的 探讨铁剥夺对HL－60细胞凋亡及对化疗药物诱导HL－60细胞凋亡的影响。方法 HL－60细胞与不同浓度的铁螯合剂－去铁胺（DFO）、DFO加化疗药物、化疗药物、DFO加化疗药物及三氯化铁、三氯化铁共同培养6h、12h、24h、48h。通过测定细胞活力,观察细胞形态学变化,应用流式细胞仪检测和DNA凝胶电泳等方法观察细胞凋亡;通过亲和免疫组化方法检测c-myc基因表达,从而确定DFO及DFO与化疗药物联合应用对HL－60细胞的作用。结果 DFO单用可降低HL－60细胞活力、抑制HL－60细胞增殖、诱导HL－60凋亡,并可使c-myc基因表达增加,其作用强度随培养时间延长及DFO浓度增加而增加。DFO与化疗药物联合时,可增加化疗药物诱导HL－60细胞凋亡的作用。该作用可被等摩尔的三氯化铁抵消。结论 铁剥夺可影响HL－60细胞DNA的合成,诱导其凋亡,并提高HL－60细胞对化疗药物的敏感性。因此,铁剥夺可作为临床上白血病治疗或辅助治疗的方法之一,不适当补铁或升高血红蛋白将影响化疗疗效。     

HL-60细胞铁池变化与凋亡相关基因关系的初步研究

目的探讨HL-60细胞铁池改变对凋亡相关基因表达的影响及可能的分子机制。方法实验分组为去铁胺(DFO)组、DFO+三氯化铁组及空白对照组,分别采用钙黄绿素检测HL-60细胞LIP、流式细胞术观察HL-60细胞凋亡和RT-PCR测定HL-60细胞bax、c-myc、rbmRNA表达。结果(1)不同浓度的DFO作用于HL-60细胞后,随培养时间延长及DFO浓度的增加,动态铁池降低,细胞生存率逐渐下降,显示一定的时间剂量依赖性。(2)不同浓度的DFO作用于HL-60不同时间后,细胞凋亡增加,高于对照组(P<0.05)。(3)RT-PCR结果显示,DFO能明显上调c-myc、rb和baxmRNA表达(P<0.05)。结论DFO通过螯合细胞内铁,降低HL-60细胞LIP,诱导细胞凋亡;诱导HL-60细胞凋亡的作用可能与其降低细胞动态铁池,上调细胞凋亡相关基因c-myc、rb、baxmRNA表达密切相关。     

铁剥夺对K562细胞动态铁池的改变及凋亡相关基因表达的影响

目的探讨去铁胺(DFO)对白血病细胞K562动态铁池(LIP)、凋亡和凋亡相关基因表达的影响及其分子机制。方法实验分为DFO组、DFO 三氯化铁组及空白对照组,分别采用钙黄绿素检测K562细胞LIP改变、流式细胞术观察K562细胞凋亡和RT-PCR测定K562细胞c-myc、Rbb、ax mRNA表达。结果1.不同浓度的DFO作用于K562细胞后,随培养时间延长及DFO浓度增加,LIP降低,细胞生存率逐渐下降,显示一定的时间剂量依赖性。2.不同浓度的DFO作用于K562不同时间后,细胞凋亡增加,高于对照组(P<0.05);3.RT-PCR结果显示,DFO能明显上调c-myc、Rb和bax mRNA表达(P<0.05)。结论DFO可诱导K562细胞凋亡;其诱导K562细胞凋亡作用可能与其螯合细胞内铁,降低细胞LIP,上调细胞凋亡相关基因c-myc、Rb、bax mRNA表达密切相关。     

去铁胺联合阿糖胞苷诱导HL-60细胞凋亡作用的实验研究

目的：探讨铁螯合剂联合阿糖胞苷诱导HL-60细胞凋亡的作用。方法：实验分为5组：空白对照组、去铁胺组、阿糖胞苷组、去铁胺+ 阿糖胞苷组、去铁胺+阿糖胞苷+三氯化铁组。上述各组与HL-60细胞共同培养6,12,24,4 8 h。通过测定细胞活力、形态学变化、流式细胞仪检测和DNA凝胶电泳等观察细胞凋亡等方法观察诱导HL-60细胞的作用。结果：去铁胺+阿糖胞苷可协同降低HL-60 细胞活力、抑制HL-60细胞增殖、诱导HL-60细胞凋亡,其作用随培养时间延长及药物浓度增加而增强。结论：铁螯合剂协同阿糖胞苷具有增强诱导HL-60细胞凋亡 的作用。     

富铁对HL—60细胞增生及化疗药物诱导HL—60细胞凋亡的影响

探讨铁对HL－60细胞增生及化疗药物诱导HL－60细胞凋亡的影响,采用HL－60细胞与不同浓度的三氯化铁、三氯化铁加阿糖胞苷、三氯化铁加足叶乙甙、阿糖胞苷、足叶乙甙共同体外培养6h、12h、24h、48h,用细胞生长、活力测定、形态学观察、流式细胞学检测分析和DNA电泳,免疫组化方法检测bcl-2基因等细胞凋亡指标观察三氯化铁的作用。结果显示,100umol/L三氯化铁促HL－60细胞增生最明显,凋亡率明低,bcl-2阳性表达率最高,100umol/L三氯化铁分别加用阿糖胞苷、足叶乙甙与HL－60细胞共同培养时期凋亡率 比单用阿糖胞苷、足叶乙甙低（P＜0.05)。可以认为一定量的铁有促进HL－60细胞增生、抑制HL－60 细胞凋亡的作用,对于白血病患者,不适当的铁剂补充可能带来不利的影响。     

铁剥夺和铁超负荷对白血病细胞株HL-60凋亡的影响机制

目的探讨铁剥夺和铁超负荷对白血病细胞株HL-60细胞凋亡的影响及其机制,为临床采用铁剥夺策略治疗或辅助治疗白血病提供理论依据。方法在HL-60细胞培养基中分别加入不同浓度的去铁胺(DFO)或三氯化铁(FeCl3),造成细胞内铁剥夺或铁超负荷状态,采取噻唑蓝(MTT)法、DNA原位末端标记染色法(TUNEL)、免疫组化法检测铁剥夺和铁超负荷状态下HL-60细胞活力、凋亡率、细胞色素C(Cyt C)阳性细胞率。结果 DFO组细胞活力呈明显下降趋势,凋亡率呈显著上升趋势;FeCl3组细胞活力和凋亡率与对照组相比呈下降趋势;DFO组细胞胞浆内Cyt C阳性细胞率与对照组相比明显升高;而FeCl3组细胞浆内Cyt C阳性细胞率与对照组相比无明显差异。结论铁剥夺可促进线粒体释放Cyt C,诱导HL-60细胞凋亡;铁超负荷对线粒体释放Cyt C无直接影响作用。     

铁对白血病细胞HL-60线粒体膜电位及凋亡的影响

目的研究铁对人白血病细胞HL-60线粒体膜电位(ΔΨm)及凋亡影响,探讨其可能机制。方法HL-60细胞分别与10、50、100μmol/L去铁胺(DFO)和10、100μmol/L三氯化铁(FeCl3)共培养,分别造成细胞内铁剥夺和富铁状态,噻唑蓝(MTT)法检测不同铁状态下细胞活力变化;相差显微镜观察凋亡细胞的形态学改变,流式细胞仪(FCM)检测细胞凋亡率及ΔΨm变化;原位杂交法检测凋亡基因Bax转录水平。结果DFO组细胞生长率呈下降趋势,而FeCl3组细胞生长率呈上升趋势;HL-60细胞经DFO处理后,细胞凋亡率增加、ΔΨm下降(P<0.01);100μmol/L DFO作用细胞244、8 h后,凋亡基因Bax的转录水平均较对照组增高(P<0.01)。FeCl3组细胞ΔΨm及Bax转录无明显变化,但凋亡率较对照组略下降。结论铁剥夺可降低ΔΨm,诱导HL-60细胞凋亡;而富铁对细胞ΔΨm无明显影响,但可增强细胞活力,使细胞凋亡率下降。     

rhTNF—α对HL—60细胞凋亡其bcl—2基因表达的影响

目的：探讨重组人肿瘤死因子－α（rhTNF-α）对白血病细胞的作用及其机制,寻求白血病免疫疗法的理论依据。方法：以早幼白血病细胞株HL－60细胞为研究对象,利用苏木素染色及免疫细胞化学的方法,观察rhTNF-α对HL－60细胞凋亡其bcl-2基因表达的影响。结果10U/ml、100U/ml和500U/mlrhTNF-α与HL－60细胞共同培养2－24h,除10U/ml培养2h组外余各组凋亡细胞均明显高于空白对照组（P＜0．05）,bcl-2基因阳性表达细胞数均明显低于空白对照组（P＜0．05）,二者呈明显负相关。随rhTNF-α浓度增高,其作用增强,8h为作用的高峰时间。结论：rhTNF-α能促进HL－60细胞的凋亡;抑制凋亡调控基因bcl-2的表达可能是TNF-α促进HL－60细胞凋亡的机制之一。     

去铁胺诱导K562细胞凋亡研究

目的：探讨铁螯合剂去铁胺（DFO）诱导白血病细胞凋亡的分子机制。方法：实验分为DFO组(终浓度分别为10、50、100 μM)、DFO+FeCl3（各10 μmol/L）组及空白对照组。用钙黄绿素检测K562细胞可变铁池。锥虫蓝活细胞拒染实验进行活细胞计数及细胞存活率测定;光镜形态学观察及流式细胞仪方法检测K562细胞凋亡;比色法检测caspase-3活性。结果：（1）DFO作用于K562细胞后,随培养时间延长及DFO浓度的增加,动态铁池降低,细胞生存率逐渐下降,凋亡率增加,显示一定的时间剂量依赖性;而DFO+FeCl3组细胞凋亡率与空白对照组差异无统计学意义。（2）50 μmo/L、100 μmol/L DFO作用于K562细胞24 h时,caspase-3酶活性升高明显,与对照组相比,差异有统计学意义(P<0.01);相关分析结果显示,K562细胞铁池的荧光改变与caspase-3活性变化呈负相关(r=-0.894, P<0.05)。结论：DFO诱导白血病细胞凋亡的作用可能与螯合细胞内铁,降低细胞可变铁池,激活caspase-3有关。     

铁超载与铁剥夺对HL-60细胞bcl-2和cmy-c基因的影响

目的探讨铁超载与铁剥夺对HL60细胞bc12和cmyc基因表达的影响。方法体外培养HL60细胞,分别加入不同浓度的三氯化铁(FeC13)。采用免疫组化LASB法测定凋亡相关基因bc12及cmyc表达。结果不同浓度的FeC13作用于HL60细胞6h、12h、24h、48h,bc12表达显著高于对照组。尤以100μmolLFeC13组显著,与对照组相比差异显著(P<0.05)。不同浓度DFO作用于HL60细胞一定时间后,其cmyc表达增高。结论铁超载时bc12高表达,铁剥夺时cmyc高表达。     

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.