胃癌腹膜腔种植转移的MSCT表现

目的:探讨胃癌腹膜腔种植转移的多层螺旋CT影像特征。方法:收集经手术探查和腹膜腔穿刺证实为腹膜腔转移的胃癌患者的腹部CT图像。分析CT图像上肠壁增厚部位和增强方式,网膜、系膜有无增厚、结节以及增强方式,有无腹水以及分布部位,肾盂输尿管积水以及有肝脾转移等。对接受2次以上CT复查者,观察CT表现的变化。结果:胃癌腹膜腔转移104例,男67例,女37例。73例显示结肠肠壁增厚,其中71例增厚肠壁有强化,31例呈层状强化。42例显示直肠肠壁增厚,其中41例强化,25例显示层状强化。55例发现腹膜腔积液。3例显示网膜或系膜增厚,14例显示网膜或系膜结节影。肾盂输尿管积水27例,胸腔积液6例,腹腔肿块2例。结论:胃癌腹膜腔种植转移的CT表现为大肠壁增厚和肠壁环形强化、腹膜腔积液与肾盂输尿管积水。腹膜增厚、网膜结节和腹腔肿块发生率低。

Current status of surgical treatment of colorectal liver metastases

Liver metastasis （LM） is one of the major causes of death in patients with colorectal cancer （CRC）. Approxi-mately 60% of CRC patients develop LM during the course of their illness. About 85% of these patients have unresectable disease at the time of presenta-tion. Surgical resection is currently the only curative treatment for patients with colorectal LM （CRLM）. In recent years, with the help of modern multimodality therapy including systemic chemotherapy, radiation therapy, and surgery, the outcomes of CRLM treatment have signifcantly improved. This article summarizes the current status of surgical treatment of CRLM including evaluation of resectability, treatment for resectable LM, conversion therapy and liver transplantation for unresectable cases, liver resection for recurrent CRLM and elderly patients, and surgery for concomitanthepatic and extra-hepatic metastatic disease （EHMD）. We believe that with the help of modern multimodality therapy, an aggressive oncosurgical approach should be implemented as it has the possibility of achieving a cure, even when EHMD is present in patients with CRLM.

Chloromycetin resistance of clinically isolated E coli is conversed by using EGS technique to repress the Chloromycetin acetyl transferase

AIM： To explore the possibility of repression of chloromycetin （Cm） acyl transferase by using external guided sequence （EGS） in order to converse the clinical E coli isolates from Cm- resistant to Cm- sensitive. METHODS： EGS directed against chloromycetin acetyl transferase gene （cat） was cloned to vector pEGFP-C1 which contains the kanamycin （Kin） resistance gene. The recombinant plasmid pEGFP-C1＋EGScatl＋cat2 was constructed and the blank vector without EGS fragment was used as control plasmids. By using the CaCl2 transformation method, the recombinant plasmids were introduced into the clinically isolated Cm resistant but Km sensitive E coli strains. Transformants were screened on LB agar plates containing Kin. Extraction of plasmids and PCR were applied to identify the positive clones. The growth curve of EGS transformed bacteria cultured in broth with Cm resistance was determined by using spectrophotometer at A600. Drug sensitivity was tested in solid culture containing Cm by using KB method. RESULTS： Transformation studies were carried out on 16 clinically isolated Cm-resistant （250 μg/mL of Cm） E colistrains by using pEGFP-C1-EGScatlcat2 recombinant plasmid. Transformants were screened on LB-agar plates containing Km after the transformation using EGS. Of the 16 tested strains, 4 strains were transformed successfully. Transformants with EGS plasmid showed growth inhibition when grown in liquid broth culture containing 200 μg/mL of Cm. In drug sensitivity test, these strains were sensitive to Cm on LB-agar plates containing 200 μg/mL of Cm. Extraction of plasmids and PCR amplification showed the existence of EGS plasmids in these four transformed strains. These results indicated that the Cat of the four clinical isolates had been suppressed and the four strains were converted to Cm sensitive ones. CONCLUSION： The EGS directed against Cat is able to inhibit the expression of Cat, and hence convert Cm- resistant bacteria to Cm-sensitive ones. Thus, the EGS has the capability of converting the phenotype of clinical drug-resistant isolates strains to drug-sensitive ones.

Pyogenic liver abscesses associated with nonmetastatic colorectal cancers: An increasing problem in Eastern Asia

AIM: To elaborate the clinicopathologic features of colorectal cancer-related pyogenic liver abscess (PLA). METHODS: Reported cases of colorectal cancer-related PLAs were collected from the literature published up to October 2011 and evaluated for their clinicopathologic features. Data of collected cases included demographics, clinical presentation, microbial findings and treatment. Categorical variables were compared by 2 analysis and continuous variables were evaluated using Student's t test. RESULTS: A total 96 cases of colorectal cancer-related PLA were collected from the previous literature. Most patients (60%) were male and 40% cases occurred in the age group of 61-70 years. Apart from some special types of PLA, there were significant differences in the microbiological spectrum between Eastern Asia and non-Eastern Asian countries, which implied different risk factors and courses of the disease. Gram negative bacteria especially Klebsiella pneumoniae (K. pneu- moniae ) PLA was predominant in Eastern Asia (80.0%) in contrast to non-Eastern Asian countries (P < 0.01). Meanwhile, most of the Eastern Asian patients exhibited smaller size of liver abscess and atypical presentation. Sigmoid colon and rectum (72.73%) were the main sites of tumor in Eastern Asian patients, whereas tumor sites were uneven among most of the non-Easter Asian PLA patients. CONCLUSION:K. pneumoniae PLA was strongly associated with colorectal cancer, especially those occurring in sigmoid colon and rectum, in elderly Eastern Asian male patients.

Investigation of the relationship between DNA-dependent protein kinase and lymphatic metastasis in colorectal cancer

Objective: To investigate DNA-dependent protein kinase (DNA-PK) expression,and its relationship with lymphat-ic metastasis in colorectal cancer. Methods: Tumor tissues from 60 patients,divided into two groups according to lymphatic metastasis,were immunohistochemically stained to detect the DNA-PK expression including Ku70,Ku80 and PKcs proteins. Results: Positivity of both Ku70 and Ku80 in colorectal cancer was negatively correlated with lymphatic metastasis with an r value of -0.57 and -0.38,respectively. Similar correlation was found between Ku expression,especially Ku70,and long-term survival. PKcs,however,displayed no significant correlation. Statistical analysis failed to detect any correlation between DNA-PK expression,and clinical characteristics,such as age,sex,tumor location,tumor thickness and distant metastasis (P>0.05). Conclusion: DNA-PK expression,especially Ku70 expression,is negatively correlated with lymphatic metastasis,and the survival of patients with colorectal cancer. Ku70 expression may be a potential indicator for the preoperative evaluation,and prognosis in colorectal cancer.

Liver angiogenesis: tumor host interaction in non-metastatic colorectal cancer

Objective: Angiogenesis is a crucial step for tumor growth and progression. Changes of liver angiogenesis (without metastatic invasion) in response to primary tumors are not known. The aim of the study was to investigate the liver angiogenesis in non-metastatic colorectal cancer (CRC). Methods: Human colorectal adenocarcinoma tumors were grown subcutaneously in nude mice. All animals showed tumor growth locally without macroscopic or microscopic evidence of liver metastases. Livers were investigated for their microvessel density (MVD) at different stages of tumor growth (as small, medium, and large-sized tumors). Normal non-tumor-bearing mice served as controls. To assess MVD, two endothelial cell markers (anti-CD34 and -CD31 antibodies), image analysis, and immunofluorescent technique were utilized. Enumeration of positive stained endothelial cells revealed the MVD. Results: Non-metastatic livers showed increased levels of MVD vs. control. Moreover, levels of MVD were higher in small and medium-sized tumor groups versus large sized tumor groups. Conclusion: The present data indicate that angiogenesis in the liver is induced in early-stages of CRC. However, this effect is suppressed with advanced tumor growth. These results provide an additional rationale for including antiangiogenic therapy in the treatment of early stages of CRC.

The roles of micro RNAs and epithelial-mesenchymal transition in colorectal cancer metastasis

Colorectal cancer(CRC) is the second most common cause of cancer death worldwide. Distant metastasis is the major cause of death in patients with CRC. During progression to metastasis in which malignant cells disseminate from the primary tumor to seeding other organs, a multistep process is involved. Cancer cells proliferate, invade microenvironment, enter into the blood circulation, then survive and colonize into distant organs. Micro RNAs(mi RNAs) and epithelial-mesenchymal transition(EMT) are key regulators and mechanism in tumorigenesis and cancer metastasis. We review the roles of EMT and micro RNAs, especially EMT related micro RNAs in the metastatic pathway of CRC. Micro RNAs provide us a set of potential therapeutic applications and molecular target for CRC.

N-Acetyltransferase 2 genetic polymorphisms and risk of colorectal cancer

AIM:To investigate the possible association between meat intake,cigarette smoking and N-acetyltransferase 2 (NAT2) genetic polymorphisms on colorectal cancer (CRC) risk.METHODS:Patients with CRC were matched for gender and age to healthy controls.Meat intake and cigarette smoking were assessed using a specific frequency questionnaire.DNA was extracted from peripheral blood and the genotypes of the polymorphism were assessed by polymerase chain reaction-restriction fragment length polymorphism.Five NAT2 alleles were studied (WT,M1,M2,M3 and M4) using specific digestion enzymes.RESULTS:A total of 147 patients with colorectal cancer (76 women and 90 men with colon cancer) and 212 controls were studied.The mean age of the two groups was 62 years.More than half the subjects (59.8% in the case group and 51.9% in the control group) were NAT2 slow acetylators.The odds ratio for colorectal cancer was 1.38 (95% CI:0.90-2.12) in slow acetylators.Although the number of women was small (n=76 in the case group),the cancer risk was found to be lower in intermediate (W/Mx) acetylators [odds ratio (OR):0.55,95% confidence interval (95% CI):0.29-1.02].This difference was not observed in men (OR:0.56,95% CI:0.16-2.00).Among NAT2 fast acetylators (W/W or W/Mx),meat consumption more than 3 times a week increased the risk of colorectal cancer (OR:2.05,95% CI:1.01-4.16).In contrast,cigarette smoking increased the risk of CRC among slow acetylators (OR:1.97,95% CI:1.02-3.79).CONCLUSION:The risk of CRC was higher among fast acetylators who reported a higher meat intake.Slow NAT2 acetylation was associated with an increased risk of CRC.