Genetic analysis and identification of candidate genes for two spotted-leaf mutants (spl101 and spl102) in rice.

Spotted-leaf mutants form spots in leaves or leaf sheaths under normal condition. The spotted-leaf phenotypes are similar to hypersensitive reaction of plants attacked by pathogen. Identification and characterization of the spotted-leaf mutants are helpful for understanding the mechanisms of resistance to plant diseases. Here, we identify two spotted-leaf mutants spl101 and spl102 from an EMS-treated elite japonica cultivar KYJ (Kuanyejing). spl101 and spl102 form serious spots at the late heading stage. Genetic analyses show that the spotted-leaf phenotypes of both spl101 and spl102 are caused by a single recessive mutation, respectively. By employing the Mutmap method, we reveal that both spl101 and spl102 contain mutations in the OsEDR1 gene. The spl101 mutation occurs in the 5°-splicing site of the 6th intron of OsEDR1, which causes abnormal recognition of the 6th intron and leads to the frameshift mutation. The spl102 mutant contains a mutation in the tenth exon of OsEDR1, resulting in an amino acid change from the phenylalanine (F) to the cysteine (C). OsEDR1 has been reported to regulate pathogen-resistant reaction, and loss of OsEDR1 function produces similar phenotypes to those of spl101 and spl102. Here, two newly identified alleles of OsEDR1 will be benefit for further understanding the molecular mechanisms of the OsEDR1 gene in disease resistance, and will be helpful for enriching the rice germplasm resources. In addition, our results also validate the effectiveness of the Mutmap method in cloning the candidate mutations.

[Dynamic contrast-enhanced MSCT findings of intraductal papillary neoplasm of the bile ducts].

OBJECTIVE: To investigate the findings of contrast-enhanced multislice computed tomography (MSCT) that characterize intraductal papillary neoplasms of bile ducts (IPNB). METHODS: The MSCT findings and clinical data of 16 cases of IPNB proven by surgical pathology were reviewed retrospectively. RESULTS: Among the 16 cases, nine were adenoma (multi-lesions, n = 5; single lesions, n = 4) and seven were adenocarcinoma (multi-lesions, n = 4; single lesions, n = 3). Among the nine adenoma cases, seven showed nodules or masses in the expanding intrahepatic bile ducts with asymmetrical low density on plain scan, and two showed obvious expansion of biliary ducts and the inner wall of bile ducts was rough. All seven of the adenocarcinoma cases showed nodules or masses in the expanding intrahepatic bile ducts with asymmetrical low density-like adenoma. When contrast enhancement was applied, the nine adenoma cases manifested slight-to-moderate degrees of asymmetrical enhancement. For the seven adenocarcinoma cases, two showed asymmetrical enhancement similar to that of the adenoma cases and five showed continued enhancement; one case showed malignant infiltration of the bile duct and evident damage in the adjacent hepatic tissue. The CT plain scan findings for the two groups (adenoma and adenocarcinoma) were not significantly different (t = -1.17, P = 0.2632). Significantly different findings were obtained with the MSCT imaging analysis for the arterial phase (t = 6.53, P less than 0.01) and the portal vein phase (t = 5.63, P less than 0.01). All cases showed asymmetrical expansion of intrahepatic biliary ducts, diffuse or local, and four cases showed moderate expansion of the common bile duct. One adenocarcinoma case showed intumescence in the celiac lymph node by moderate asymmetrical enhancement. CONCLUSION: MSCT is helpful for the differential diagnosis of IPNB from other hepatic lesions.

miR-495 and miR-551a inhibit the migration and invasion of human gastric cancer cells by directly interacting with PRL-3.

The phosphatase of regenerating liver-3 (PRL-3) gene is associated with metastasis in gastric cancer, and is believed to play a causative role by promoting tumor cell motility, invasion, and metastasis, but little is known of the mechanisms involved. We previously reported that PRL-3 expression is significantly higher in the tissues of primary gastric carcinomas with peritoneal metastasis. In the present study, we found that two microRNAs (miRNAs), miR-495 and miR-551a, predicted to target PRL-3, are downregulated in gastric carcinoma samples. The validation of this interaction between those two miRNAs and PRL-3 was confirmed by western blotting and quantitative real-time PCR (qPCR) in GC cell lines transfected with miR-495 and miR-551a mimics. Furthermore, the migration and invasion of GC cells were significantly inhibited by transfection with miR-495 or -551a mimics, and the mRNA and protein levels of PRL-3 were reduced in cells overexpressing miR-495 or -551a. Collectively, our findings suggest that miR-495 and miR-551a both act as tumor suppressors by targeting the PRL-3 oncogene and inhibiting gastric cancer cell migration and invasion. The findings of this study contribute to current understanding of the functions of miRNA mimics in GC gene therapy.

[Necessity of No.13 lymph node dissection in advanced gastric carcinoma].

OBJECTIVE: To investigate the feasibility and necessity of No.13 lymph node dissection for advanced gastric carcinoma. METHODS: Clinical data of 144 cases who were diagnosed as TNMII-III stage gastric carcinoma were collected from January 2007 to December 2009 in the Department of General Surgery at the First Affiliated Hospital of Nanchang University. Seventy-two cases who received D2 radical gastrectomy plus No.13 lymph node dissection were selected as the study group, and they were matched 1:1 to 72 cases who received D2 Radical gastrectomy (the control group) for TNMII-III stage gastric carcinoma. The differences in the intraoperative and postoperative parameters and survival time were compared, and the factors associated with No.13 lymph node metastasis were analyzed. RESULTS: There were no significant differences between the two groups in operative time [(2.8 ± 0.4) h vs. (2.7 ± 0.4) h], blood loss [(191.9 ± 81.5) ml vs. (186.0 ± 81.7) ml], the incidence of postoperative complications (18.1% vs. 15.3%), length of hospital stay [(12.3 ± 4.2) d vs. (11.9 ± 3.2) d] and 3-year survival rate (63% vs. 57%) (all P>0.05). In the study group, there were 15 patients (20.8%) with positive No.13 lymph nodes, and the 3-year survival rate was 13%, significantly lower compared to those with negative No.13 lymph node (73%, n=57) (P<0.05). Multivariate analysis showed that N stage (P<0.01) and histological type (P<0.05) were independently associated with No.13 lymph node metastasis. CONCLUSION: No.13 lymph node dissection for TNMII-III stage gastric cancer is feasible and necessary.