急性白血病骨髓细胞的端粒酶活性研究

目的：研究初治急性白血病患者骨髓细胞的端粒酶活性,并与正常骨髓、白血病细胞株进行比较,探讨其临床意义。方法：运用PCR-ELISA法半定量检测20例正常骨髓、5种白血病细胞株和32例初治急性白血病患者骨髓单个核细胞的端粒酶活性,将其中9例急性白血病缓解后与缓解前端粒酶水平作比较。结果：正常骨髓单个核细胞端粒酶表达范围为0～0.30 U,平均（0.11±0.08）U,其中仅有3例阳性,阳性率15％;5种白血病细胞株均为阳性,表达范围在0.92～1.00 U之间,平均端粒酶活性（0.96±0.02）U;急性白血病骨髓单个核细胞端粒酶表达范围为0～0.96 U,平均（0.42±0.26）U,阳性率78.1％,与正常骨髓相比,差异有显著性（P< 0.001）。初治急性白血病端粒酶活性高低与首次缓解率无关。9例初治白血病患者缓解后,其中2例急性早幼粒细胞白血病M3端粒酶表达转阴,进行自体外周血干细胞移植后持续阴性,其余患者较初诊时端粒酶水平有所下降,但仍高于正常。1例急性淋巴细胞白血病经过大剂量巩固治疗后端粒酶水平进一步下降,在自体外周血干细胞移植后6个月仍表达阳性,移植后9个月复发。结论：正常骨髓细胞中端粒酶活性很低,急性白血病骨髓细胞端粒酶活性明显高于正常,联合化疗缓解后端粒酶活性下降但仍高于正常。端粒酶     

儿童急性白血病端粒酶活性检测及临床意义

目的：探讨端粒酶活性在儿童急性白血病中的表达及临床意义。方法：采用端粒重复系列扩增法（TRAP）检测了11例儿童急性白血病化疗前、完全解后骨髓单个核细胞（MNCs)端粒酶活性水平,对部分病例进行追踪观察,并与10例正常儿童骨髓MNCs端粒酶活性相比较。结果：正常骨髓MNCs具低水平的端粒酶活性,相对端粒酶活性范围2．6％－19．1％;急性白血病患儿化疗前相对端粒酶活性明显增高40．4％－98％,完全缓解后其相对端粒酶活性为21．7％－60．1％,随缓解时间的延长,端粒酶活性逐渐降低。结论：端粒酶激活在儿童急性白血病的发生中可能具有重要作用,动态观察端粒酶活性水平,对估测病情、监测微小残留病可能具有实际意义。     

骨髓增生异常综合征骨髓细胞端粒酶活性和端粒酶逆转录酶的表达

目的　探讨骨髓增生异常综合征 ( MDS)骨髓细胞端粒酶活性与端粒酶逆转录酶表达的关系及临床意义。方法　采用端粒重复序列扩增 -酶联免疫吸附试验 ( TRAP- EL ISA)检测端粒酶活性 ,RT- PCR法检测端粒酶逆转录酶 ( h TERT) m RNA水平的表达。结果　高危组 MDS患者骨髓细胞端粒酶活性较低危组 MDS患者骨髓细胞端粒酶活性明显增高 ( 0 .2 0 0± 0 .2 2 5 vs 0 .0 2 7± 0 .0 13,P=0 .0 37) ;正常人、缺铁性贫血 ( IDA)患者和低危组 MDS患者骨髓细胞 h TERT m RNA表达检测结果均阴性 ,而高危组 MDS患者和急性白血病 ( AL )患者骨髓细胞均表达h TERT基因 ;h TERT m RNA表达和端粒酶活性呈正相关 ( r=0 .774 ,P=0 .0 2 4 )。结论　端粒酶活性与 h TERT基因 m RNA水平的异常表达能反映出 MDS病情的进展。定期检测 MDS患者骨髓细胞端粒酶活性和 h TERTm RNA水平的表达可作为观察 MDS患者病情变化的指标之一。     

胃癌及癌前病变组织中端粒酶RNA表达及其临床意义

目的 探讨胃癌及癌前病变胃粘膜端粒酶RNA与端粒酶活性检测及临床意义。方法 分别采用原位逆转录－PCR、端粒重复序列扩增法（TRAP）检测114例胃粘膜组织标本端粒酶RNA与端粒酶活性,其中包括慢性浅表性胃炎（CSG）32例、不典型增生（AH）34例、胃癌（GC）48例。结果 原位逆转录－PCR检测胃粘膜活检标本的端粒酶RNA阳性率为57．9％（66／114）,显著高于TRAP法检测端粒酶活性检出率（44．7％,51／114,P＜0．05）。在不同胃粘膜病变中,AH及GC组的端粒酶RNA阳性率分别为52．9％、100％,而CSG组胃粘膜中未检出端粒酶RNA;AH及GC组的胃粘膜端粒酶RNA阳性率分别显著高于CSG（P＜0．05）,而GC组端粒酶RNA阳性率亦明显高于AH组（P＜0．05）。端粒酶RNA主要分布于胃粘膜癌细胞及癌前病变上皮细胞的胞核内。结论 端粒酶RNA表达与胃癌的发生密切相关。原位逆转录－PCR检测胃粘膜端粒酶RNA可能是较端粒酶活性更灵敏的生物学指标,对胃粘膜癌变的预测和早期诊断有重要价值。     

急性白血病端粒酶活性与p53蛋白表达规律的研究

目的：探讨争性白血病（AL）患者中端粒酶活性与突变型P53蛋白的表达规律,方法：采用聚合酶链反应一酶联免疫吸附法（PCR－ELISA）对端粒酶活性进行定半量测定,用流式细胞仪检测突变型P53蛋白表达,结果：AL患者端粒酶性显著高于对照组＊（P＜0．001）,端粒酶活性在AL的不同病期有统计学差异,其中初治组,复发组均显著高于完全缓解CR组（P＜0．01）,在治疗敏感组与不敏感组间无统计学差异（P＞0．05）,AL患者中突变型P53蛋白阳性率为19．4％（7／36）,在AL的不同病期P53阳性率无统计学差别。在初治敏感组与不敏感组之间亦无统计学差别（P均＞0．05）,端粒酶活性与突变型P53蛋白的表达无关。结论：端粒酶活性与AL的病期和发展密切相关,突变型P53蛋白在AL中表达较低,对临床预后的判断价值较小,端粒酶的激活与P53蛋白表达无相关性。     

原发性肺癌端粒酶活性检测及其临床应用价值

目的：研究原发性肺癌组织端粒酶活性检测的临床应用价值。探讨其作为肺癌诊断和预后评价指标的可行性。方法：采用端粒重复序列扩增－酶联免疫吸附法（TRAP－ELISA法），对32例原发性肺癌手术切除组织及相应的癌旁组织进行端粒酶活性分析，并以7例肺良性病变作为对照。结果：32例肺癌组织端粒酶水平明显高于癌旁组织（P＜0．05），及良性病变组织（P＜0．001），肺癌组织中端粒酶阳性率为84．4％，癌 旁组织为9．4％，在良性组织中未检出端粒酶阳性，端粒酶活性随临床分期有升高趋势，伴淋巴结转移标本组中其阳性率明显高于非淋巴结转移组（P＜0．05），但与肿瘤病理组织学类型，分化程度等未显示有统计学差异。结论：端粒酶激活与肺癌的发生，发展密切相关，端粒酶可以成为一种用于肺癌辅助诊断，预后判断的重要标志物并在肺癌的基因治疗中发挥作用。     

肺癌脱落细胞端粒酶活性检测的临床意义

目的：探讨肺癌脱落细胞端粒酶活性检测的临床意义。方法：收集63例肺癌患者和31例非肺癌肺疾病患者的支气管肺泡灌洗液，同时行刷片和灌洗液细胞学检查；34例肺癌患者痰液，31例非肺癌肺疾病患者痰液；彩PCR－TRAP银染法检测端粒酶活性。结果：肺癌和非肺癌肺疾病支气管肺泡灌洗液端粒酶活性阳性率分别为76．2％（48／63）和6．5％（2／31），P＜0．01；肺癌支气管肺泡灌洗液端粒酶活性阳性率高于刷片细胞学阳性率（58．7％，37／63），P＞0．05；高于灌洗液细胞学阳性率（14．7％，9／63），P＜0．01。肺癌痰液和非肺癌肺疾病痰液端粒酶活性阳性率分别为29．4％（10／34），3．2％（1／31），P＜0．01。结论：肺癌端粒酶活性检测有较高的特异性和敏感性，可应用于肺癌的临床诊断。支气管肺泡灌洗液和痰液端粒酶检测能提高肺癌检出率。     

特发性血小板减少性紫癜与人类疱疹病毒6型感染关系初探

目的：了解特发性血小板减少性紫癜与人类疱疹病毒6型（HHV－6）感染间的关系。方法：聚合酶链反应（PCR）检测特发性血小板减少性紫癜（ITP）骨髓，外周血中的HHV－6－DNA健康体检者和缺铁性贫血者为对照组。结果：20例ITP患者，10例缺铁性贫血患者和30例健康体检者外周血的HHV－6－DNA检出率分别为25％（5／20），10％（1／10）和3．33％（1／30），ITP患者组与健康体检组间，差异有显著性（P＜0．05）。ITP患者组与缺铁性贫血组间差异无显著性。15例ITP患者骨髓和10例缺铁性贫血患者骨髓，HHV－6－DNA检出率分别为46．67％（7／15）和0，二者间差异有显著性（P＜0．05）。10例ITP治疗前，治疗后第5天，第10天时外周血HHV－6－DNA检测，分别有3，3，2例阳性。结论：ITP与HHV－6的感染呈正相关，骨髓中HHV－6－DNA检出率高于外周血中     

急性白血病端粒酶检测及临床相关分析

目的　检测急性白血病细胞端粒酶活性与临床相关分析。方法　端粒重复扩增法 (TRAP)结合光密度定量分析端粒酶活性和临床病例资料分析。结果　在急性白血病初诊期或复发期均表现很高的端粒酶活性 ,缓解期病例活性降低 ,骨髓增生异常综合征转变为急性白血病者及慢性粒细胞白血病急性变后端粒酶活性明显增高。结论　急性白血病较高的端粒酶活性与临床病情演变相关 ,分析白血病细胞端粒酶活性 ,对白血病临床诊断和治疗具有一定意义。     

白血病细胞端粒酶活性的研究

目的：研究白血病细胞端粒酶活性表达及其意义。方法：采用PCR-ELISA半定量方法测定端粒酶活性。结果：68.6％(59／86)急性白血病(AL)患者和80％(12／15)慢性粒细胞白血病急性变(CML-BP)患者表达高端粒酶活性；而慢性粒细胞白血病慢性期(CML-CP)患者，无一例表达高端粒酶活性。急性淋巴细胞白血病患者端粒酶活性高于急性髓性白血病患者，CML-BP端粒酶活性高于CML-CP，而CML-CP端粒酶活性则低于正常对照组。AL端粒酶活性水平与患者的性别、年龄无关，也与治疗后缓解率无关。结论：激活或上调端粒酶活性在大多数AL发生和慢性粒细胞白血病急性变过程中起着重要作用；端粒酶活性测定可鉴别CML-BP与CML-CP；端粒酶可能是一潜在的治疗白血病的新靶点。     

急性白血病组织中端粒酶活性与p170共同表达及其临床意义

目的探讨急性白血病(acute leukemia,AL)组织中中端粒酶和p170共同表达与患者化疗疗效及预后的关系。方法采用TRAP法检测43例AL患者治疗前、后端粒酶活性;流式细胞仪检测p170表达。结果端粒酶活性与p170表达呈正相关性,r=0.745,P=0.02;双阳者CR率为29.4%(5/17);双阴者CR率高达83.3%(10/12);两者差异有统计学意义,P=0.04。结论AL患者端粒酶与p170共表达者临床缓解率更低,更有预后意义。     

Telomerase activity and hTERT mRNA expression in acute leukemia

Telomerase is specifically activated in mostmalignant tumors but is usually inactive in normalsomatic cells, suggesting that telomerase plays animportant role in cellular immortalization andtumorigenesis. Telomerase activity has been the mostgeneral molecular marker for the identification ofhuman cancer and can be detected in 85% of alltumors[1,2]. Although several studies have investigatedtelomerase activity in leukemia, few studies haveinvestigated the diagnostic importance of hTERTexpressi…     

Therapy for acute myeloid leukemia and acute lymphoblastic leukemia in adults

Using intensive induction chemotherapy, primarily with combinations of an anthracycline and cytarabine, complete remission rates of greater than 70% are now achieved in patients with acute myeloid leukemia under the age of 60 years. The treatment of elderly patients with acute myeloid leukemia is difficult and remains controversial. The prognosis for both adults and children with acute lymphoblastic leukemia has improved as more extensive chemotherapy regimens have been used. Recently, a group of leukemias have been identified that have features of both acute lymphoblastic leukemia and acute myeloid leukemia, and these are referred to as biphenotypic or hybrid leukemias. These hybrid leukemias represent an important subgroup, which appears to have a worse outcome regardless of the therapy administered.     

国产去甲氧柔红霉素和进口柔红霉素治疗急性白血病的疗效及安全性比较

 目的　对比国产去甲氧柔红霉素（IDA）和进口柔红霉素（DNR）在急性白血病治疗中的的疗效和安全性。方法　68例急性白血病患者随机分为IDA组35 例和DNR组33例。IDA组35 例患者中,急性髓细胞白血病用IA（国产IDA、阿糖胞苷）方案治疗,急性淋巴细胞白血病用VICLP（长春新碱、国产IDA、环磷酰胺、左旋门氡酰氨酶和泼尼松）方案治疗;同期DNR组33例患者中,急性髓细胞白血病用DA（进口DNR、阿糖胞苷）方案治疗,急性淋巴细胞白血病用VDCLP（长春新碱、进口DNR、环磷酰胺、左旋门氡酰氨酶和泼尼松）方案治疗。结果　IDA组完全缓解21例,部分缓解5例,总缓解率74.2 %（26／35）,DNR组完全缓解16例,部分缓解4例,总缓解率62.3 %（20／33）,两组总缓解率差异无统计学意义（χ2＝0.89,P＝0.50）;IDA组缓解时间超过一年者占完全缓解患者的80 %（17／21）,而DNR组为37.5 %（6／16）,两组差异有统计学意义（χ2＝5.56,P＝0.02）。结论　国产IDA治疗急性白血病缓解率及长期缓解率均优于进口DNR,是疗效确切、安全可靠的抗白血病药物。     

Amplification of hTERT and hTERC genes in leukemic cells with high expression and activity of telomerase

Reactivation of telomerase plays an important role in carcinogenesis. Malignant cells almost always possess high activity and expression of telomerase. The aim of this study was to see whether there is any relationship between telomerase activity and expression and hTERT and hTERC gene amplification in acute lymphoblastic leukemia (ALL) and non-lymphoblastic leukemia (ANLL) cells. In addition telomere length was tested in leukemic cells at the time of diagnosis and during remission. Expression of the three components of telomerase (hTERT, hTERC and TP1) as well as telomerase activity was found both in ALL and ANLL cells. Telomerase activity was diminished in patients in remission. The leukemic cells showed considerable heterogeneity of terminal restriction fragments, that is telomere length. ALL cells showed a variable pattern of telomere length in contrast to ANLL cells which produced a predominantly short telomere pattern. Telomere length in the lymphocytes of leukemia patients was shorter in remission as compared to the time of diagnosis. FISH analysis revealed amplification of hTERT and hTERC genes in ALL and ANLL cells. Quantitative analysis showed that leukemic cells possess higher number of hTERT and hTERC copies than the normal PBL. Our results suggest that the activation of telomerase in leukemic cells is connected with amplification of hTERT and hTERC genes. The high expression and activity of telomerase found in leukemic cells may be partially explained by amplified hTERT and hTERC genes. Amplification of the telomerase genes seems to be a common event in carcinogenesis and may play a role in telomerase reactivation leading to cell immortalization.     

Telomerase inhibition enhances apoptosis in human acute leukemia cells: possibility of antitelomerase therapy.

Telomerase is a ribonucleoprotein enzyme that maintains protective structures at the ends of eukaryotic chromosomes. We examined the impact of telomerase inhibition by the dominant-negative human catalytic subunit of telomerase (DN-hTERT) on the biological features of acute leukemia. We introduced vectors encoding dominant- negative (DN)-hTERT, wild-type (WT)-hTERT, or a control vector expressing only a drug-resistant marker into a telomerase-positive human acute lymphoblastic leukemia cell line, HAL-01. Expression of DN-hTERT dramatically inhibited telomerase activity, leading to apoptotic cell death. Mutant telomerase expression also enhanced daunorubicin-induced apoptosis. Nude mice (n=5 per group) received subcutanous implants of HAL-01 cells expressing the control vector or DN-hTERT or WT-hTERT. Implantation of HAL-01 cells expressing control vector (n=5) rapidly produced tumors, whereas implantation of those expressing DN-hTERT (n=5) did not. Thus, telomerase inhibition both growth of HAL-01 cells in vitro and tumorigenic capacity in vivo. Furthermore, the G-quadruplex-interactive telomerase-specific inhibitor, telomestatin, shortened the telomere length and induced apoptosis in freshly isolated primary acute leukemia cells. These results suggest that antitelomerase therapy may be useful in some acute leukemias in combination with antileukemic agents such as daunorubicin.