二硅化钼改性硅酸镱环境障涂层的高温抗氧化行为及机理

新一代高推重比航空发动机的发展对环境障涂层(EBCs)的服役寿命和温度提出了苛刻的要求。稀土硅酸盐作为EBCs材料应用于面层,在服役过程中易产生纵向裂纹,为腐蚀性介质的侵蚀提供通道,严重影响EBCs的寿命。二硅化钼(MoSi_(2))具有优异的高温性能,有望改善稀土硅酸盐EBCs体系的高温性能。采用MoSi_(2)改性Yb_(2)SiO_(5)面层,通过真空等离子喷涂技术(VPS)分别制备了Yb_(2)SiO_(5)-XMoSi_(2)(X=0,5%和10%,体积分数)为面层,Yb_(2)Si_(2)O_(7)为中间层,Si为黏结层的三种环境障涂层体系。研究了涂层在1350℃长时间氧化前后显微结构演化过程。结果发现,掺杂MoSi_(2)涂层体系在高温氧化500 h后仍能保持结构完整且面层裂纹减少。原因在于,MoSi_(2)可消耗氧化剂,减缓涂层内部TGO的增长速率,反应产物Yb_(2)Si_(2)O_(7)与中间层成分一致,具有较好的化学相容性,有效改善了涂层体系的高温性能。

Two-dimensional Sb net generated nontrivial topological states in SmAgSb_(2) probed by quantum oscillations

The REAgSb_(2)(RE = rare earth and Y) family has drawn considerable research interest because the two-dimensional Sb net in their crystal structures hosts topological fermions and hence rich topological properties. We report herein the magnetization and magnetotransport measurements of SmAgSb_(2) single crystal, which unveil very large magnetoresistance and high carrier mobility up to 6.2 × 10^(3)% and 5.58 × 10^(3)cm^(2)·V^(-1)·s^(-1), respectively. The analysis of both Shubnikov–de Haas and de Haas–van Alphen quantum oscillations indicates nontrivial Berry phases in the paramagnetic state while trivial Berry curvature in the antiferromagnetic state, indicating a topological phase transition induced by the antiferromagnetic order. It is also supported by the first-principles calculations. The results not only provide a new interesting topological material but also offer valuable insights into the correlation between magnetism and nontrivial topological states.

Intestinal stem cell marker LGR5 expression during gastric carcinogenesis

AIM:To investigate the differential expression of leu-cine-rich repeat-containing G protein-coupled receptor5(LGR5)in gastric cancer tissues and its significance related to tumor growth and spread.METHODS:Formalin-fixed biopsy specimens of intestinal metaplasia(n=90),dysplasia(n=53),gastric adenocarcinoma(n=180),metastases in lymph nodes and the liver(n=15),and lesion-adjacent normal gastric mucosa(controls;n=145)were obtained for analysis from the Peking University Cancer Hospital’s Department of Pathology and Gastrointestinal Surgery tissue archives(January 2003 to December 2011).The biopsied patients’demographic and clinicopathologic data were retrieved from the hospital’s medical records database.Each specimen was subjected to histopathological typing to classify the tumor node metastasis(TNM)stage and to immunohistochemistry staining to detect the expression of the cancer stem cell marker LGR5.The intergroup differences in LGR5 expression were assessed by Spearman’s rank correlation analysis,and the relationship between LGR5 expression level and the patients’clinicopathological characteristics was evaluated by theχ2test or Fisher’s exact test.RESULTS:Significantly more gastric cancer tissues showed LGR5+staining than normal control tissues(all P<0.01),with immunoreactivity detected in 72.2%(65/90)and 50.9%(27/53)of intestinal metaplasia and dysplasia specimens,respectively,52.8%(95/180)of gastric adenocarcinoma specimens,and 73.3%%(11/15)of metastasis specimens,but 26.9%(39/145)of lesion-adjacent normal gastric mucosa specimens.Comparison of the intensity of LGR5+staining showed an increasing trend that generally followed increasing dedifferentiation and tumor spread(normal tissue<dysplasia,<gastric adenocarcinoma<metastasis;all P<0.001),with the exception of expression level detected in intestinal metaplasia which was higher than that in normal gastric tissues(P<0.001).Moreover,gastric cancer-associated enhanced expression of LGR5 was found to be signifcantly associated with age,tumor differentiation,Lauren type and TNM stage(Ⅰ+ⅡvsⅢ+Ⅳ)(all P<0.05),but not with sex,tumor site,location,size,histology,lymphovascular invasion,depth of invasion,lymph node metastasis or distant metastasis.Patients with LGR5+gastric cancer specimens and without signs of metastasis from the original biopsy experienced more frequent rates of recurrence or metastasis during follow-up than patients with LGR5-specimens(P<0.05).CONCLUSION:Enhanced LGR5 is related to progressive dedifferentiation and metastasis of gastric cancer,indicating the potential of this receptor as an early diagnostic and prognostic biomarker.

Nanoheterostructured photocatalysts for improving photocatalytic hydrogen production

Rapid industrialization has accordingly increased the demand for energy.This has resulted in the increasingly severe energy and environmental crises.Hydrogen production,based on the photocatalytic water splitting driven by sunlight,is able to directly convert solar energy into a usable or storable energy resource,which is considered to be an ideal alternative energy source to assist in solving the energy crisis and environmental pollution.Unfortunately,the hydrogen production efficiency of single phase photocatalysts is too low to meet the practical requirements.The construction of heterostructured photocatalyst systems,which are comprised of multiple components or multiple phases,is an efficient method to facilitate the separation of electron‐hole pairs to minimize the energy‐waste,provide more electrons,enhance their redox ability,and hence improve the photocatalytic activity.We summarize the recent progress in the rational design and fabrication of nanoheterostructured photocatalysts.The heterojunction photocatalytic hydrogen generation systems can be divided into type‐I,type‐II,pn‐junction and Z‐scheme junction,according to the differences in the transfer of the photogenerated electrons and holes.Finally,a summary and some of the challenges and prospects for the future development of heterojunction photocatalytic systems are discussed.

Predictive factors of endoscopic submucosal dissection procedure time for gastric superficial neoplasia

AIM:To identify the determinants of endoscopic submucosal dissection(ESD) operation time.METHODS:This investigation was conducted as a single-center,prospective study in which ESD was performed by the same endoscopist at the Chinese PLA General Hospital.A total of 173 patients underwent ESD operations performed by Dr.Lu from July 2007 to December 2011,and 183 lesions were enrolled.Patient gender,age,tumor location,gross type,tumor size,pathological type and adhesions were recorded prospectively.The order of treatment represented the experience of the operator.Univariate analysis and multivariate analysis were performed to evaluate the relationships between these factors and ESD procedure time.RESULTS:Univariate analysis showed the ESD time was closely related to the gender(P = 0.0210),tumor size(P < 0.0001),location(P < 0.0001),gross type(P < 0.0001) and adhesion(P = 0.0010).The surgical proficiency level was associated with ESD time in unit area(P < 0.0001).Multivariate analysis revealed that the ESD time was positively correlated with tumor size(P < 0.0001),adhesion(P < 0.0001) and location(P < 0.0001),but negatively correlated with surgical proficiency level(P = 0.0046).CONCLUSION:Large tumor size,adjacency to the cardia,and adhesion are predictors of a long ESD time,whereas high surgical proficiency level predicts a short ESD time.

Novel endoscopic papillectomy for reducing postoperative adverse events(with videos)

BACKGROUND Pancreatic adenoma can potentially transform into adenocarcinoma, so it is recommended to be resected surgically or endoscopically. Endoscopic papillectomy is one of the main treatments for papillary adenoma, and bleeding, perforation, and pancreatitis are the most frequent and critical adverse events that restrict its wider use. There is no standard procedure for endoscopic papillectomy yet. The procedure is relevant to postoperative adverse events.AIM To reduce the postoperative adverse event rates and improve patients' postoperative condition, we developed a standard novel procedure for endoscopic papillectomy.METHODS The novel endoscopic papillectomy had two main modifications based on the conventional method: The isolation of bile from pancreatic juice with a bile duct stent and wound surface protection with metal clips and fibrin glue. We performed a single-center retrospective comparison study on the novel and conventional methods to examine the feasibility of the novel method for reducing postoperative adverse events.RESULTS A total of 76 patients, of whom 23 underwent the novel procedure and 53 underwent the conventional procedure, were retrospectively evaluated in this study. The postoperative bleeding and pancreatitis rates of the novel method were significantly lower than those of the conventional method(0 vs 20.75%, P = 0.028, and 17.4% vs 41.5%, P = 0.042, respectively). After applying the novel method, the most critical adverse event, perforation, was entirely prevented, compared to a prevalence of 5.66% with the conventional method. Several postoperative symptoms, including fever, rapid pulse, and decrease in hemoglobin level, were significantly less frequent in the novel group(P = 0.042, 0.049, and 0.014, respectively). Overall, the total adverse event rate of the novel method was lower(0 vs 24.5%, P = 0.007) than that of the conventional method.CONCLUSION Patients who underwent the novel procedure had lower postoperative adverse event rates. This study demonstrates the potential efficacy and safety of the novel endoscopic papillectomy in reducing postoperative adverse events.

固酶纳米复合物光电催化性能评估的综合实验——多学科交叉综合性实验教学改革实践

针对现有固酶二氧化钛-碳纳米材料复合物基光电化学传感器存在的环境适应性和抗干扰性欠佳、灵敏度和底物选择性不够高以及构效关系研究不足等问题,系统探讨了不同功能单元与二氧化钛/碳基纳米材料之间各种相互作用与纳米复合物各基元结构、组成以及理化性质之间的关联。在此基础上确定制约其传感效能和应用价值的关键因素,阐述了未来构筑此类传感器构效关系模型所需解决的重点问题。本文设计了一个典型的综合性实验,介绍了固载牛血红蛋白的二氧化钛纳米球-3D氧化石墨烯共价偶联复合物基电极的制备方法。使学生掌握综合运用多种表征测试技术考察固载酶分子与载体各基元间相互作用对酶参与光电催化反应各相关步骤动力学的影响的方法,并了解固酶电极光电催化动力学参数测定的相关理论和方法。

Different methods of acupuncture for relief of pain due to liver cancer:A network meta-analysis

BACKGROUND Pain in the liver is a common symptom of liver cancer in late stages,and the pain incidence rate exceeds 50%[1].In serious cancer pain,morphine and other major analgesics have been commonly administrated for clinical treatments,and their effects are accurate,but with a high incidence of side effects,such as nausea,vomiting,constipation,and other conditions.Acupuncture is a traditional Chinese medicine therapy.There have been many randomized controlled trials addressing the safety and usefulness of different methods of acupuncture in alleviating liver cancer pain.However,which of these methods is the most effective method is still unclear.AIM To compare the effectiveness of different acupuncture methods for alleviating pain due to liver cancer.METHODS Eligible studies were retrieved from eight databases(the Cochrane Library,PubMed,EMBASE,Medline,CNKI,CBM,Chongqing VIP,and Wan Fang Database)up to March 31,2021 and screened based on the established inclusion and exclusion criteria.The quality of the include studies was evaluated.Stata software was applied for statistical analyses.Publication bias of the included studies was also determined.Finally,the network meta-analysis was carried out to evaluate the efficacy of acupuncture methods for relief of pain due to liver cancer.RESULTS A total of eight randomized controlled trials were included in the network metaanalysis.Eight trials(covering 5 treatments and 734 patients)provided data suitable for analysis.Most trials focused on short-term effects and many were classed as being of poor quality with a high risk of bias,commonly associated with lack of blinding(which was sometimes impossible to achieve).End of treatment results showed that four interventions,including wrist-ankle acupuncture,triple puncture and remaining needle acupuncture,Tian Yuan acupuncture,and block acupuncture,produced a statistically significant reduction in pain when compared with the three-step analgesic ladder therapy.The surface under the cumulative ranking sorting results showed that triple puncture and remaining needle acupuncture had a relatively high effective rate.CONCLUSION The network meta-analysis results indicate that the overall effectiveness of triple puncture and remaining needle acupuncture is better than the other therapies.

二硅化钼改性硅酸镱环境障涂层体系抗热震行为及机理

稀土硅酸盐环境障涂层(EBCs)是应用于新一代高推重比航空发动机热端部件的重要材料,但在服役过程中,稀土硅酸盐面层易产生纵向裂纹,为腐蚀性介质进入EBCs体系内部提供通道,使硅黏结层发生氧化并产生裂纹,最终导致EBCs失效。二硅化钼(MoSi_(2))具有优异的高温性能,有望改善稀土硅酸盐EBCs体系的高温稳定性。本工作采用MoSi_(2)改性Yb_(2)SiO_(5)面层,通过真空等离子喷涂技术(VPS)分别制备了以Yb2SiO5、Yb_(2)SiO_(5)-5%MoSi_(2)(体积分数,下同)和Yb_(2)SiO_(5)-10%MoSi_(2)作为面层,以Yb_(2)Si_(2)O_(7)作为中间层,以Si作为黏结层的三种环境障涂层体系,利用场发射扫描电子显微镜表征了涂层在1350℃热震前后的形貌变化。结果表明:掺杂MoSi_(2)不仅能改善涂层的损伤容限,还可消耗氧化性介质,减少其向涂层体系内部的扩散,使黏结层上TGO层厚度分别降低83%和88%,从而有效改善涂层体系的高温稳定性。

TiAl合金表面TiAlCrY/YSZ涂层高温长时间服役性能

TiAl合金具有低密度、高比强度的优异性能,是一种潜在的航空发动机用结构材料。TiAl合金的服役温度范围为700~900℃,在其表面制备高温热防护涂层可以进一步提高服役温度。本研究采用等离子喷涂技术在TiAl合金表面制备了新型TiAlCrY/YSZ涂层,并与传统的NiCrAlY/YSZ热障涂层进行高温长时间服役性能对比研究。结果发现,TiAlCrY/YSZ涂层在1100℃空气环境中服役300 h保持完好,表现出良好的高温性能,而NiCrAlY/YSZ涂层在1100℃的服役寿命不足100 h。显微分析结果表明,TiAlCrY黏结层表面会形成一层连续且致密的TGO,其主要成分为Al2O3,与YSZ涂层的界面兼容性良好。并且TGO在1100℃空气环境中服役300 h后,厚度仍<8μm。以上研究表明,与传统NiCrAlY/YSZ热障涂层相比,TiAlCrY/YSZ更适合作为TiAl合金表面的高温热防护涂层。

渗碳处理对等离子喷涂TaC涂层结构和物相组成的影响

TaC涂层在还原气氛下能耐酸、碱、盐等物质的腐蚀,是优异的表面防护涂层材料。本文结合喷雾干燥与等离子球化技术制备TaC粉体,并采用真空等离子喷涂技术制备TaC涂层。采用真空碳管炉对涂层进行渗碳处理,比较研究不同渗碳温度对涂层结构和物相组成的影响。结果发现,相较于喷雾造粒,等离子球化处理的TaC粉体呈致密球形,该粉体制备的涂层较为致密,孔隙率较低。此外,喷涂过程中TaC发生脱碳产生Ta_(2)C相,而渗碳反应可以将喷涂过程中产生的Ta_(2)C相转化成TaC相。Ta_(2)C与C反应生成TaC的过程受动力学控制,当渗碳温度超过900℃时,几乎完全转化为TaC相。

Transcriptome Analysis and Physiological Responses of Economic Macroalga Gracilariopsis lemaneiformis under Sulfate Deficiency

Sulfur is an essential macronutrient for the growth of all photosynthetic organisms and plays important roles in different metabolic pathways.However,sulfur metabolism and its related research on macroalgae with important ecological value is rather limited.In this study,marine ecological valued macroalga Gracilariopsis lemaneiformis was used to study the general physiological responses and transcriptome profiling under the sulfate deficiency.The relative growth rate of algae under sulfate deficiency was statistically significantly lower than that of control after 6 days.However,no significant differences were observed in the pigments content and Fv/Fm value,indicating that the photosynthesis was not obviously affected under the sulfate deficiency.Furthermore,the significantly increased soluble protein and carbohydrate contents,and indistinctively differentially expressed sulfate transporter/permease(ST)and ATP sulfurylase(ATPS)genes suggesting that G.lemaneiformis cells did not use sulfur from internal protein and carbohydrate pools but utilize stored sulfur from vacuole to satisfy their nutritional requirements during the sulfate deficiency.Transcriptome data showed that most annotated differentially expressed genes(DEGs)were down-regulated under the sulfate deficiency,including a large proportion of genes involved in the pathway of sulfur metabolism.Therefore,it was concluded that the pathway of sulfur metabolism was suppressed under the sulfate deficiency in G.lemaneiformis.The results and analysis in this study provide a comprehensive understanding for the physiological and molecular response of G.lemaneiformis to sulfate deficiency.

大型气液同轴喷射分布器数学模拟

大型浆态床的气液分布器设计需要同时考虑气体均布、气液传质和防止堵塞三个方面的要求,基于此提出了一种大孔径气液同轴喷射的分布器构型.首先通过单喷嘴冷模实验测量了全塔平均气含率和大、小气泡相含率,证明气液同轴喷射能够显著强化气液传质,减小气泡直径.随后对所设计的外径6.3 m的多环大型气液分布器内部的流动进行了三维瞬态模拟以探讨改进气体均布的措施,模拟发现,对于多环分布管结构,采用管径随环径增大的变直径分布器代替常用的等直径分布器能够明显改善气体分布的均匀性.最后对该分布器在不同载荷下的气体均布指标进行了计算机模拟,结果表明在±40%的负荷变化范围内,分布器的气体均布性能仍然比较稳定,能够满足工业应用的要求.

喷射环流反应器的放大效应

实验测量了两种塔径( 200 和 500 mm)和两种操作模式(气体单独喷射和气液同轴喷射)下喷射环流反应器内的全塔平均气含率、局部气含率及轴向液速径向分布、循环液速,归纳出全塔平均气含率的关联式。实验发现,喷射环流反应器具有十分显著的放大效应。小塔( 200)与大塔( 500)中的全塔平均气含率存在很大差异:小塔的全塔平均气含率~气速关系曲线比大塔陡峭,低气速下小塔气含率低于大塔、较高气速下高于大塔。根据漂移通量法分析得到小塔中流型转变点在表观气速 0.1 m s 1左右,在实验气速范围内只存在拟均匀鼓泡流;大塔中流型转变点在表观气速 0.04 m s 1左右,随气速增大从拟均匀鼓泡流转变为湍动鼓泡流。喷射环流反应器比气升式环流反应器、一般鼓泡塔全塔平均气含率略低,但循环液速更大,适用于强化固体悬浮与混合的气液固三相反应过程。

等离子喷涂TiC-Graphite复合涂层摩擦磨损性能

等离子喷涂TiC涂层具有良好的综合性能,在极端环境能起到较好的耐磨保护作用,而石墨是一种优异的自润滑材料。通过喷雾干燥与真空烧结技术制备不同石墨添加量(1.25%、2.5%、5%和10%,质量分数)的TiC-Graphite球形粉体,并采用大气等离子喷涂技术制备TiC-Graphite复合涂层。对涂层的相组成、显微结构和力学性能进行了表征,并对涂层的摩擦磨损性能进行了比较研究。结果发现,TiC-Graphite涂层主要由TiC和石墨相组成。随石墨添加量增大,TiC-Graphite涂层截面微裂纹增多,表面粗糙度增大,硬度下降。石墨对TiC涂层在高载荷的磨损性能影响更显著。在50 N高载荷条件,随石墨添加量增大,TiC-Graphite涂层磨损率降低后急剧增大,而摩擦系数持续减小。当石墨添加量为2.5%时,涂层获得最低的磨损率为0.67×10^(−5) mm^(3)/(N·m),同时具有较低的摩擦系数(0.35),与不添加石墨的TiC涂层相比,分别降低了72.4%和27.8%。

Level of circulating PD-L1 expression in patients with advanced gastric cancer and its clinical implications

Objective：The programmed cell death-1 receptor/programmed cell death-1 ligand （PD-1/PD-L1） pathway plays a crucial role in tumor evasion from host immunity.This study was designed to evaluate the association between circulating PD-L1 expression and prognosis in patients with advanced gastric cancer.Methods：Totally 80 advanced gastric cancer patients and 40 health controls from Beijing Cancer Hospital were enrolled in the present study.Circulating PD-L1 expression was tested by enzymelinked immunosorbent assay （ELISA）.The associations between the expression level of PD-L1 and clinicopathological features and prognosis were analyzed statistically.Results：Expression of PD-L1 in advanced gastric cancer patients was significandy up-regulated compared with health people （P=0.006）.The expression of PD-L1 was significantly correlated with differentiation and lymph node metastasis （P=0.026 and P=0.041,respectively）.Although we didn＇t find significant difference in all advanced gastric cancer patients with different PD-L1 expression,the adenocarcinoma patients with higher up-regulated PD-L1 expression had much better prognosis than low expression patients （65.6％ vs.44.7％,P=0.028）.Conclusions：PD-L1 was elevated in advance gastric cancer patients and may play an important role in tumor immune evasion and patients prognosis.

LGR5 is a promising biomarker for patients with stage Ⅰ and Ⅱ gastric cancer

Objective： To investigate Leucine-rich repeat-containing G protein-coupled receptor 5 （LGR5） expressions in gastric cancer and to evaluate its clinical significance. Methods： LGR5 expression was assessed by immunohistochemistry in 257 gastric cancer patients after surgery. The relationships between LGR5 expression and clinicopathological features and patients prognosis were statistically analyzed. Results： The expression of LGR5 was significantly higher in gastric cancers as a cancer stem cell marker than in adjacent normal tissues （P〈0.001）, and more frequently in patients with intestinal type, well-moderate differentiation and stage I and II （P〈0.05）. Although we found gastric cancer patients with LGR5 positive expression had a poorer prognosis, it didn＇t meet statistical significance （P〉0.05）. LGR5 negative expression was significantly related to the favorable overall survival in stage I and II gastric cancer patients （P〈0.05）. Furthermore, patients with high LGR5 expression tended to be more likely to get progression and have poorer progress-free survival （P〈0.05）. Multivariate Cox regression analysis revealed that LGR5 expression was an independent factor of overall survival for the patients with stage I and II gastric cancer （P〈0.05）. Conclusions： Our results show that LGR5 may play an important role in tumorigenesis and progression and would be a powerful marker to predict the prognosis of patients with stage I and II gastric cancer.

Treatment of nutcracker syndrome with spermatic vein ligation and iliac vein anastomosis:Case report of three cases

Three patients with nutcracker syndrome(NCS) were enrolled in the study.Their clinical symptoms mainly included proteinuria and serious varicocele.Color Doppler ultrasound and computed tomography showed that the patients had constricted abdominal aortas,reduced superior mesenteric artery angles,and thinned left renal veins.Patients then underwent left spermatic vein ligation and iliac vein anastomosis.They were checked tliree months after their operation,and results showed that their sperms were improved and their proteinuria disappeared. The color Doppler ultrasound showed new cycle pathways.NCS clinical manifestations are complicated,and need combination diagnosis of symptoms and auxiliary examination to detennine surgical indications.Ligation of spermatic vein and vein anastomosis can be used to treat NCS.

Over-expression of Metastasis-associated in Colon Cancer-1 (MACC1) Associates with Better Prognosis of Gastric Cancer Patients

Objective： The aim of this study was to detect metastasis-associated in colon cancer-1 （MACC1） expression in Chinese gastric cancer and analyze the relationship between MACC1 expression and postoperative survival. Methods： The expression of MACC1 and c-MET protein in a sample of 128 gastric cancer tissues was detected by immunohistochemistry. A retrospective cohort study on the prognosis was carried out and data were collected from medical records. Results： The positive rate of MACC1 protein expression in gastric cancer was 47.66%, higher than that in adjacent noncancerous mucosa （P0.001）. MACC1 protein expression was not related to the clinicopathological variables involved. Kaplan-Meier analysis revealed that the survival of MACC1 positive group tended to be better than that of MACC1 negative group, particularly in patients with stage III carcinoma （P=0.032）. Cox regression analysis revealed that MACC1 protein over-expression in gastric cancer tended to be a protective factor with hazard ratio of 0.621 （P=0.057）. Immunohistochemical analysis showed that the positive rate of c-MET protein expression was much higher in cases with positive MACC1 expression in gastric cancer （P=0.002）, but P53 expression was not associated with MACC1 expression. Conclusion： MACC1 over-expression implies better survival and may be an independent prognostic factor for gastric cancer in Chinese patients.

Decreased fragile histidine triad expression in colorectal cancer and its association with apoptosis inhibition

AIM： To detect the expression of fragile histidine triad （FHIT） in normal colorectal tissue, colorectal adenoma and colorectal cancer （CRC） tissue, and to analyze its relationship with the clinicopathological features of CRC, and apoptosis-associatecl proteins （Bcl-2, Bax, survivin） and apoptosis in colorectal cancer. METHODS： FHIT mRNA analysis was performed by nested reverse transcription-polymerase chain reaction （RT-PCR） assay. Tissue microarray （TMA） was established to detect the expression of FHIT, Bcl-2, Bax and survivin genes in 80 CRC tissue specimens, 16 colorectal adenoma tissue specimens and 16 hemorrhoid （PPH） tissue specimens during the same period of time as the control. Citrate-microwave-SP was used as immunohistochemical method. The relationship between clinicopathological factors, such as differentiation grades and 5-year survival rate was observed. TUNEL assay was used to detect the apoptosis index in 80 CRC tissue specimens. RESULTS： Ten out of 26 （38.5%） CRC tissue specimens expressed aberrant FHIT transcripts, none of the aberrant FHIT transcripts was observed in the matchednormal tissue and colorectal adenoma tissue by nested RT-PCR assay. The positive rate of FHIT gene expression in normal colorectal tissue, colorectal adenoma and carcinoma tissue was 93.75%, 68.75% and 46.25%, respectively. Clinicopathological analysis of patients showed that the decreased FHIT gene expression was not associated with age, sex, serum CEA levels, tumor site and size, histological classification. However, the expression of FHIT was correlated with differentiation grades, pathological stages, lymph node metastases and 5-year survival rate after operation. The positive rate of apoptosis-associated proteins （Bax, Bcl-2 and survivin） in CRC tissue was 72.50%, 51.25% and 77.50%, respectively. The expression of these apoptosisassociated proteins in CRC tissue was correlated with the expression of FHIT. The mean apoptosis index in FHIT negative tumors was significantly lower than that in FHIT- positive tumors （5.41 ± 0.23 vs 0.56 ± 0.10, P 〈 0.01）. CONCLUSION： The FHIT gene plays an important role in the regulation of apoptosis and decreased FHIT expression plays a key role in the initiation and progression of colorectal carcinoma.