Enhancing the CRISPR/Cas9 system based on multiple GmU6 promoters in soybean.

Small guide RNA (sgRNA) is an important component of the CRISPR/Cas9 system. The gene editing efficiency of the CRISPR/Cas9 system could be enhanced by using highly active U6 promoters to drive the expression of sgRNA. Therefore, we constructed various expression vectors based on the 11 GmU6 promoters predicted and cloned in the whole soybean genome. The expression of truncated GUS driven by 11 GmU6 promoters was tested in hairy roots and by Arabidopsis thaliana transformation. The results indicated that higher transcriptional levels were driven by 5 GmU6 promoters (GmU6-4, GmU6-7, GmU6-8, GmU6-10 and GmU6-11) in both soybean hairy roots and Arabidopsis thaliana. In addition, three genes, Glyma03g36470, Glyma14g04180 and Glyma06g136900, were selected as targets to detect the transcriptional levels of multiple GmU6 promoters. Mutations in these three genes were detected in soybean hairy roots after Agrobacterium rhizogenes infection, indicating efficient target gene editing, including nucleotide insertion, deletion, and substitution. Mutation efficiencies differed among the 11 GmU6 promoters, ranging from 2.8% to 20.6%, and markedly higher efficiencies were obtained with all three genes using the GmU6-8 (20.3%) and GmU6-10 (20.6%) promoters. These two GmU6 promoters also showed higher ability to drive truncated GUS transcription in both soybean hairy roots and transformed Arabidopsis thaliana. These results will help to construct an efficient CRISPR-Cas9 gene editing system and promote the application of the CRISPR-Cas9 genome editing system in soybean molecular breeding.

Benzoylaconine induces mitochondrial biogenesis in mice via activating AMPK signaling cascade.

The traditional Chinese medicine "Fuzi" (Aconiti Lateralis Radix Praeparata) and its three representative alkaloids, aconitine (AC), benzoylaconine (BAC), and aconine, have been shown to increase mitochondrial mass. Whether Fuzi has effect on mitochondrial biogenesis and the underlying mechanisms remain unclear. In the present study, we focused on the effect of BAC on mitochondrial biogenesis and the underlying mechanisms. We demonstrated that Fuzi extract and its three components AC, BAC, and aconine at a concentration of 50 µM significantly increased mitochondrial mass in HepG2 cells. BAC (25, 50, 75 µM) dose-dependently promoted mitochondrial mass, mtDNA copy number, cellular ATP production, and the expression of proteins related to the oxidative phosphorylation (OXPHOS) complexes in HepG2 cells. Moreover, BAC dose-dependently increased the expression of proteins involved in AMPK signaling cascade; blocking AMPK signaling abolished BAC-induced mitochondrial biogenesis. We further revealed that BAC treatment increased the cell viability but not the cell proliferation in HepG2 cells. These in vitro results were verified in mice treated with BAC (10 mg/kg per day, ip) for 7 days. We showed that BAC administration increased oxygen consumption rate in mice, but had no significant effect on intrascapular temperature. Meanwhile, BAC administration increased mtDNA copy number and OXPHOS-related protein expression and activated AMPK signaling in the heart, liver, and muscle. These results suggest that BAC induces mitochondrial biogenesis in mice through activating AMPK signaling cascade. BAC may have the potential to be developed as a novel remedy for some diseases associated with mitochondrial dysfunction.

MicroRNA-29a Promotes Pancreatic Cancer Growth by Inhibiting Tristetraprolin.

BACKGROUND/AIMS: The microRNA (miR) 29 family has been studied extensively for its involvement in several diseases, and aberrant expression of its members is associated with tumorigenesis and cancer progression. Here, we examined the role of miR-29a in pancreatic cancer and the involvement of tristetraprolin (TTP). METHODS: We monitored miR-29a and TTP expression in pancreatic cancer by qRT-PCR and western blotting. The effect of miR-29a on pancreatic cancer was determined through MTT assay and migration assay. The results were validated in the tumorigenesis model. RESULTS: We found that miR-29a was up regulated in pancreatic tumor tissues and cell lines and positively correlated with metastasis. Ectopic expression of miR-29a increased the expression of pro-inflammatory factors and epithelial-mesenchymal transition (EMT) markers, through down regulating TTP. TTP was down regulated in tumor tissues, and its ectopic expression decreased cell viability and migration in vitro, inhibited tumor growth and the EMT phenotype in vivo, and reversed the effect of miR-29a on tumor cell proliferation and invasion in vitro and in vivo. CONCLUSION: Our results suggest that miR-29a acts as an oncogene by down regulating TTP and provide the basis for further studies exploring the potential of miR-29a and TTP as biomarkers and targets for the treatment of pancreatic cancer.

Application of chemokine receptor antagonist with stents reduces local inflammation and suppresses cancer growth.

Severe pain and obstructive jaundice resulting from invasive cholangiocarcinoma or pancreatic carcinoma can be alleviated by implantation of biliary and duodenal stents. However, stents may cause local inflammation to have an adverse effect on the patients' condition and survival. So far, no efficient approaches have been applied to prevent the occurrence of stents-related inflammation. Here, we reported significantly higher levels of serum stromal cell-derived factor 1 (SDF-1) in the patients that developed stents-associated inflammation. A higher number of inflammatory cells have been detected in the cancer close to stent in the patients with high serum SDF-1. Since chemokine plays a pivotal role in the development of inflammation, we implanted an Alzet osmotic pump with the stents to gradually release AMD3100, a specific inhibitor binding of SDF-1 and its receptor C-X-C chemokine receptor 4 (CXCR4), at the site of stents in mice that had developed pancreatic cancer. We found that AMD3100 significantly reduced local inflammation and significantly inhibited cancer cell growth, resulting in improved survival of the mice that bore cancer. Moreover, the suppression of cancer growth may be conducted through modulation of CyclinD1, p21, and p27 in the cancer cells. Together, these data suggest that inhibition of chemokine signaling at the site of stents may substantially improve survival through suppression of stent-related inflammation and tumor growth.

Foxtail millet MYB-like transcription factor SiMYB16 confers salt tolerance in transgenic rice by regulating phenylpropane pathway.

R2R3-MYB transcription factors play an important role in the synthesis of phenylpropanoid-derived compounds, which in turn provide salt tolerance in plant. In this study, we found that the expression of foxtail millet R2R3-MYB factor SiMYB16 can be induced by salt and drought. SiMYB16 is localized in the nucleus and acts as a transcriptional activator. Phylogenetic analysis indicates that SiMYB16 belongs to the R2R3-MYB transcription factor family subgroup 24. Transgenic rice expressing SiMYB16 (OX16) had a higher survival rate, lower malondialdehyde content, and heavier fresh weight compared with type (WT) under salt stress conditions. The transgenic plants also had a higher germination rate in salt treatment conditions and higher yield in the field compared with wild-type plants. Transcriptome analysis revealed that the up-regulated differential expression genes in the transgenic rice were mainly involved in phenylpropanoid biosynthesis, fatty acid elongation, phenylalanine metabolism, and flavonoid biosynthesis pathways. Quantitative real-time PCR analysis also showed that the genes encoding the major enzymes in the lignin and suberin biosynthesis pathways had higher expression level in SiMYB16 transgenic plants. Correspondingly, the content of flavonoid and lignin, and the activity of fatty acid synthase increased in SiMYB16 transgenic rice compared with wild-type plants under salt stress treatment. These results indicate that SiMYB16 gene can enhance plant salt tolerance by regulating the biosynthesis of lignin and suberin.

Erectile dysfunction in patients with traumatic urethral strictures treated with anastomotic urethroplasty: a single-factor analysis.

INTRODUCTION: To investigate factors correlated with erectile dysfunction (ED) in patients with traumatic urethral strictures undergoing end-to-end anastomotic urethroplasty (AU). MATERIALS AND METHODS: Between January 2010 and January 2011, 41 patients with urethral strictures resulting from pelvic fracture urethral distraction defects underwent end-to-end AU. The abridged International Index of Erectile Function (IIEF-5) was used to subjectively assess erectile function at admission and 2 weeks postoperatively. RESULTS: Pre- and post-injury IIEF-5 scores differed significantly (23.54 ± 1.45 versus 10.02 ± 3.57; p < 0.0001), but pre and postoperative scores did not (10.02 ± 3.57 versus 9.29 ± 4.14; p = 0.1560). Erectile function declined in all patients after injury and was postoperatively unchanged in 56.10%. Pre- and post-injury scores differed significantly in all ages, stricture location and length groups, but did not change postoperatively. Urethral injury resulted in varying degrees of ED. IIEF-5 scores declined significantly postoperatively in patients with mild/mild-moderate ED (13.86 ± 1.88 versus 11.43 ± 3.37; p = 0.0202), but were unchanged in patients with moderate/severe ED. Vascular ED was predominant (63.41%), and erectile function was better in patients with non-vascular ED than in those with arterial/venous ED (15.50 ± 2.08 versus 11.00 ± 2.35, 8.67 ± 3.21; p = 0.0037, p = 0.0183). IIEF-5 scores decreased significantly in patients with non-vascular ED postoperatively (15.50 ± 2.08 versus 10.00 ± 3.83; p = 0.0132), but were unchanged in patients with arterial/venous ED. CONCLUSION: Urethral trauma seriously affects erectile function, but subsequent end-to-end AU for urethral strictures has little impact.

[Efficacy and Safety of Intensive Maintenance Chemotherapy Regimen for Treatment of Children and Adolescents with Lymphoblastic Lymphoma for Stage III-IV].

OBJECTIVE: To investigate the efficacy and safety of intensive maintenance chemotherapy regimen for treatment of children and adolescents with lymphoblastic lymphoma at stage Ⅲ-Ⅳ. METHODS: The clinical data of 87 children and adolescents with lymphoblastic lymphoma at stage Ⅲ-Ⅳ were analyzed retrospectively from July 2009 to July 2015. All patients received the treatment of modified NHL-BFM-90/95 regimen, and divided into 2 groups: the control group (62 patients) with conventional maintenance chemotherapy regimen, and the intensive regimen group (25 patients) with intensive maintenance chemotherapy regimen. The event-free survival (EFS) rate and overall survival (OS) rate during follow-up for 5 years, recurrence rate, mortality, and toxic and side effects were compared between 2 groups. RESULTS: There was no significant difference in the EFS rate and OS rate after follow-up for 5 years between 2 groups (P＞0.05). There was no significant difference in the EFS rate and OS rate after follow-up for 5 years between clinical stage for Ⅲ and Ⅳ, immunotyping for T-LBL and B-LBL and morderate risk and high risk in 2 groups (P＜0.05). There was no significant difference in the recurrence rate and mortality after followed-up between 2 groups (P＞0.05). The incidence of myelosuppression for Ⅲ-Ⅳ grade during maintenance therapy in intensive regimen group were significantly higher than that in control group (P＜0.05). CONCLUSION: Compared with conventional maintenance chemotherapy regimen, intensive maintenance chemotherapy regimen in the treatment of children and adolescents with lymphoblastic lymphoma for stage Ⅲ-Ⅳ possess the same survival benefit, but may cause increased severe bone marrow suppression risk.

Mastl overexpression is associated with epithelial to mesenchymal transition and predicts a poor clinical outcome in gastric cancer.

Microtubule-associated serine/threonine kinase like (Mastl) is deregulated in a number of types of human malignancy and may be a kinase target for cancer treatment. The aim of the present study was to determine the Mastl expression in gastric cancer and to clarify its clinical and prognostic significance. Immunohistochemistry was performed on a cohort of 126 postoperative gastric cancer samples to detect the expression of Mastl and two epithelial to mesenchymal transition (EMT) markers, epithelial-cadherin and Vimentin. The χ2 test, Kaplan-Meier estimator analysis and Cox's regression model were used to analyze the data. Upregulated Mastl protein expression was observed in the gastric cancer tissues compared with that in the adjacent non-cancerous gastric tissues. Increased Mastl expression was identified in 54/126 (42.9%) gastric cancer samples, and was significantly associated with lymph node metastasis, tumor relapse, EMT status and poor overall survival. Additional analysis demonstrated that the Mastl expression level stratified the patient outcome in stage III, but not stage II tumor subgroups. Cox's regression analysis revealed that increased Mastl expression was an independent prognostic factor for patients with gastric cancer. Mastl expression may be a valuable prognostic marker and a potential target for patients with gastric cancer.

Role of the tumor microenvironment in pancreatic adenocarcinoma.

Pancreatic cancer is a devastating disease with proclivity for early metastasis, which accounts for its poor prognosis. The clinical problem of pancreatic cancer is its resistance to conventional therapies, such as chemotherapy or radiation. Based upon these challenges, the focus of research on pancreatic cancer has shifted gradually towards the tumor microenvironment. The cancer microenvironment consists of various components, including fibroblasts, endothelial cells, immune cells, and endocrine cells, that interact with each other, and with the cancer cells in a complex fashion. Evidence is accumulating that the cancer microenvironment plays an active role in disease progression, and efforts are being made to target this interplay between cancer cells and host cells, to improve the prognosis of the disease. In the present review, we describe the cellular microenvironment of pancreatic ductal adenocarcinoma (PDA), the major type of pancreatic cancer. Our hope is that a better understanding of the cellular microenvironment of PDA will eventually lead to better treatments for this disease.

[Expression of osteopontin mRNA and its clinical significance in gastric cancer].

OBJECTIVE: To investigate the expression of osteopontin mRNA and its correlation with clinicopathologic features of gastric cancer and elucidate its role in tumor invasion and distant metastasis. METHODS: The expression of OPN mRNA was detected by semi-quantitive RT-PCR. The relationship between the relative content of OPN mRNA and clinicopathologic features of gastric cancer was analyzed. RESULTS: In 66 cancer tissue samples, a 330 bp band was detected in 50 cases, the positive rate of OPN mRNA expression was 75.8% (50/66). The expression in all 20 cases of normal gastric mucosa was negative. The expression was associated with the depth of tumor invasion, diameter, lymph node metastasis and but had no correlation with differentiation grades. The 66 patients were followed up for 10 approximately 27 months (mean 16 months). The OPN mRNA expression positive group (50 cases) had recurrence in 15 patients and the negative group (16 cases) had only 1 case with recurrence (P = 0.05); 10 patients died in OPN mRNA expression positive group but no patient died in OPN staining negative group (P = 0.05). CONCLUSION: OPN mRNA is over-expressed in gastric cancer. It reflects the progression of disease and association with poor prognosis of gastric cancer. OPN may play an important role in the process of distant metastasis in gastric cancer.

Percutaneous needle decompression in treatment of malignant small bowel obstruction.

AIM: To investigate the efficacy and safety of percutaneous needle decompression in the treatment of malignant small bowel obstruction (MSBO). METHODS: A prospective analysis of the clinical data of 52 MSBO patients undergoing percutaneous needle decompression was performed. RESULTS: Percutaneous needle decompression was successful in all 52 patients. Statistically significant differences were observed in symptoms such as vomiting, abdominal distension and abdominal pain before and after treatment (81.6% vs 26.5%, 100% vs 8.2%, and 85.7% vs 46.9%, respectively; all P < 0.05). The overall significantly improved rate was 19.2% (11/52) and the response rate was 94.2% (49/52) using decompression combined with nasal tube placement, local arterial infusion of chemotherapy and nutritional support. During the one-month follow-up period, puncture-related complications were acceptable. CONCLUSION: Percutaneous needle intestinal decompression is a safe and effective palliative treatment for MSBO.

Combined radiochemotherapy in patients with locally advanced pancreatic cancer: a meta-analysis.

AIM: To compare the long-term clinical efficacy of chemotherapy plus radiotherapy (CRT) with that of radiotherapy alone (RT) or chemotherapy alone (CT) for locally advanced pancreatic carcinoma (LAPC). METHODS: Using manual and computer-aided methods, we searched the data through the databases, including PubMed/EmBase/CNKI/CQVIP/China Journals Full Text Database and websites and proceedings of major annual meetings such as ASCO and CSCO. The methodological quality of the included studies was assessed using the Jadad scoring system. Both English and Chinese publications were searched. We collected data from controlled clinical trials on CRT vs RT or CT for LAPC, and conducted a meta-analysis of 15 included studies. Meta-analysis was performed using RevMan4.2 Software according to the method recommended by Cochrane Collaboration. RESULTS: Fifteen eligible randomized controlled trials including a total of 1128 patients were screened. Jadad score was 2 in only one article, and 3-4 in the remaining 14 studies. The meta-analysis showed that CRT was superior in the 6- and 12-mo survivals to the RT alone group or CT alone group (P = 0.0001 and P = 0.02, respectively), whereas the 18-mo survival showed no significant difference (P = 0.23). Subgroup analysis showed that the 6-, 12-, and 18-mo survivals were not significantly different between the CRT group and CT group (P = 0.07, P = 0.23, and P = 0.91, respectively). Notably, the CRT group had significantly better 6-, 12-, and 18-mo survivals than the RT group (all P < 0.01). CRT group had significantly more grade 3-4 treatment-related hematologic and non-hematologic toxicities than the CT group or RT group (all P < 0.01). CONCLUSION: Compared with CT or RT, CRT can benefit the long-term survival of LAPC patients, although it may also increase treatment-related toxicities.

Efficacy of capecitabine and oxaliplatin regimen for extrahepatic metastasis of hepatocellular carcinoma following local treatments.

AIM: To investigate the efficacy and safety of capecitabine and oxaliplatin (CapeOx) for extrahepatic metastasis after local treatment of hepatocellular carcinoma (HCC). METHODS: Thirty-two patients with extrahepatic metastasis of HCC after local treatment were prospectively enrolled. The CapeOx regimen consisted of capecitabine 1000 mg/m(2) taken orally twice daily on days 1-14, and oxaliplatin was administered at a total dose of 100 mg/m(2) on day 1. The treatment was repeated every 3 wk until disease progression or unaccetablle toxicity. Efficacy and safety were assessable for all enrolled patients. The primary objective of this study was to assess the overall response rate. The secondary objectives were to evaluate the overall survival (OS), the time to tumor progression (TTP) and the toxicity profile of the combined strategy. TTP and OS were assessed by the Kaplan-Meier method and differences between the curves were analyzed using the log-rank test. The statistical software SPSS version 15.0 for Windows (SPSS Inc., Chicago, IL, United States) was used for statistical analysis. All P values were 2-tailed, with statistical significance defined by P ≤ 0.05. RESULTS: Thirty-two patients were assessable for efficacy and toxicity. The median follow-up duration was 15 mo (range, 12-20 mo). At the cut-off date of March 31, 2012, 27 patients died due to tumor progression and one patient died of myocardial infarction. Four patients were still alive (three patients with disease progression). OR was 21.9% (n = 7), the stabilization rate was 40.6% (n = 13), and the disease control rate was 62.5%. The responses lasted from 4 to 19 mo (median, 6 mo). Median TTP was 4.2 mo (95%CI: 2.5-7.4), and the median OS time was 9.2 mo (95%CI: 6.5-17.8). The 1-year survival rate was 43.6% (95%CI: 29.0-66.0). In a multivariate analysis, OS was significantly longer in patients with a Child-Pugh class A compared with class B patients (P = 0.014), with a median OS of 10.1 mo vs 5.4 mo, and there were trends towards longer OS (P = 0.065) in patients without portal vein tumor thrombosis. There were no significant effects of age, gender, performance status, cirrhosis, metastatic sites, and level of alpha fetoprotein (AFP) or hepatitis B virus-DNA on OS. Among the 22 patients with elevated AFP levels at baseline (≥ 400 ng/mL), the level fell by more than 50% during treatment in 6 patients (27.3%). The most frequent treatment-related grade 3 to 4 toxicities included leucopenia/neutropenia, transient elevation of aminotransferases, hand-foot syndrome and fatigue. CONCLUSION: CapeOx showed modest anti-tumor activity in metastatic HCC. However, the manageable toxicity profile and the encouraging disease control rate deserve further study for these patients.

Alteration of transcriptional profile in human bronchial epithelial cells induced by cigarette smoke condensate.

Despite the significance of cigarette smoke for carcinogenesis, the molecular mechanisms that lead to increased susceptibility of human cancers are not well-understood. In our present study, the oncogenic transforming effects of cigarette smoke condensate (CSC) were examined using papillomavirus-immortalized human bronchial epithelial cells (BEP2D). Growth kinetics, saturation density, resistance to serum-induced terminal differentiation, anchorage-independent growth and tumorigenicity in nude mice were used to investigate the various stages of transformation in BEP2D cells. Illumina microarray platforms were used to explore the CSC-induced alteration of global mRNA expression profiles of the earlier period and the advanced stage of CSC-treated BEP2D cells. We showed here that a series of sequential steps arose among CSC-treated immortalized human bronchial epithelial cells, including altered growth kinetics, resistance to serum-induced terminal differentiation, and anchorage-independence growth. In the earlier period of CSC treatment, 265 genes were down-regulated and 63 genes were up-regulated, respectively, and in the advanced stage of CSC treatment, 313 genes were down-regulated and 145 genes were up-regulated, respectively. Notably, among those genes, the expression of some of imprinted genes such as IGF2, NDN, H19 and MEG3 were all silenced or down-regulated in CSC-treated cells. These genes reactivated after 5 microM 5-aza-2-deoxycytidine (5-aza-dC) treatment. These results demonstrated that long-term treatment of human bronchial epithelial cells with CSC may adversely affect their genetic and epigenetic integrity and lead to further transformation.

Fingerprint developing of coffee flavor by gas chromatography-mass spectrometry and combined chemometrics methods.

In this paper, chromatographic fingerprint was firstly used for quality control of tobacco flavors. Based on gas chromatography-mass spectrometry (GC-MS) and combined chemometrics methods, a simple, reliable and reproducible method for developing chromatographic fingerprint of coffee flavor, one of tobacco flavors, was described. Six coffee flavor samples obtained from different locations were used to establish the fingerprint. The qualitative and quantitative analysis of coffee flavor sample from Shenzhen was completed with the help of subwindow factor analysis (SFA). Fifty-two components of 68 separated constituents in coffee flavor sample from Shenzhen, accounting for 88.42% of the total content, were identified and quantified. Then, spectral correlative chromatography (SCC) was used to extract the common peaks from other five studied coffee flavor samples. Thirty-eight components were found to exist in all six samples. Finally, the method validation of fingerprint analysis was performed based on the relative retention time and the relative peak area of common peaks, sample stability and similarity analysis. The similarities of six coffee flavor samples were more than 0.9104 and showed that samples from different locations were consistent to some extent. The developed chromatographic fingerprint was successfully used to differentiate coffee flavor from cocoa flavor and some little difference sample prepared with coffee flavor and cocoa flavor by both similarity comparison and principal component projection analysis. The developed method can be used for quality control of coffee flavor.

Comparative analysis of the volatile components in cut tobacco from different locations with gas chromatography-mass spectrometry (GC-MS) and combined chemometric methods.

A combined approach of subwindow factor analysis and orthogonal projection resolution was used to analyze the volatile components of cut tobacco samples from different sources. After extracted with simultaneous distillation and extraction method, the volatile components in cut tobacco from five different locations were detected by GC-MS. Then, the qualitative and quantitative analysis of the volatile components of cut tobacco from Changde area was completed with the help of subwindow factor analysis resolving two-dimensional original data into pure mass spectra and chromatograms. One hundred and two volatile components among 138 separated peaks were identified and quantified, accounting for about 88.90% of the total content. Finally, orthogonal projection method was used to extract the common peaks from different locations. Among the identified components, there were 74 components coexisting in five studied samples although the relative content of each component showed difference to some extent. The results showed a fair consistency in their GC-MS fingerprints. It was the first time to apply orthogonal projection method to compare different cut tobacco samples, and it reduced the burden of qualitative analysis as well as the subjectivity. The obtained results proved the combined approach powerful for the analysis of complex cut tobacco samples. The developed method can be used to compare the sameness and differences of cut tobacco from different sources and for quality control of cigarette production and materials.

[Risk factors for arrhythmia early after transcatheter closure of perimembranous ventricular septal defects].

OBJECTIVE: Perimembranous ventricular septal defects (PMVSDs) is the most common type of congenital ventricular septal defects (VSD), which accounts for 70% approximately 80% of VSD. The structure of PMVSDs is very complex, it is close to tricuspid valve, mitral valve and aortic valve. The atrioventricular (AV) node is located in the posterior upper membranous ventricular septum and branches into left and right bundle in the posterior lower margin. This increases the risk of transcatheter closure of PMVSDs. Arrhythmias is the common complication after transcatheter closure of PMVSDs. The present study aimed to identify the risk factors resulting in arrhythmias after transcatheter closure of PMVSDs in patients under 18 years of age to decrease the incidence of arrhythmias after the interventional catheterization. METHODS: A retrospective analysis was performed on the patients treated with transcatheter intervention from June 2002 to June 2004. Transcatheter closure of PMVSDs with Amplatzer membranous septal occluder and a domestic product was performed in 89 cases after obtaining consent themselves and/or their guardian or parents, 47 cases were males and 42 females. The age of the cases ranged from 3 to 18 years (mean 8.2 years) and the body weight ranged from 13 to 55 kg (mean 26.7 kg). They were all diagnosed as having PMVSDs with trans-thoracic echocardiography (TTE) before the interventional catheterization, the electrocardiographic (ECG) and chest X-ray (CXR) findings were recorded. A simultaneous care ECG and TTE were performed during operation in order to identify the effect of the transcatheter closure, the heart structure and functional changes and whether or not arrhythmias occurred, respectively. In 80 cases AGA Amplatzer membranous septal occluder was used and in 9 cases a domestic product was used. Follow-up was performed based on the echocardiography and ECG. RESULTS: The devices were successfully implanted in 89 cases; 11 cases (12%) developed various block of heart conduction within 5 days, which included first degree AV block in 1 patient, third degree AV block in 1, left anterior bundle branch block in 5, partial right bundle branch block in 4, complete right bundle branch block in 3, and 3 patients had two kinds of heart block. Eight patients were treated with corticosteroids, 6 of them recovered within 14 days, 1 patient within 1 month and in 1 case the problem shifted from first degree block and left anterior bundle branch block to left anterior bundle branch block 5 days later and that persisted for 6 months. It was found that the distance from upper margin of defects to the aortic valve < 3 mm, the diameter of ventricular septal defect > or = 8 mm, the diameter of device > or = 10 mm, blood pH < 7.35 and arteriovenous track building time after the success of the Seldinger technique > or = 60 min were independent predictors of post-closure arrhythmias. CONCLUSION: Arrhythmias remain the severe early complications after interventional catheterization for PMVSDs in patients under 18 years of age. Shortening of operation time, prevention of acidosis and strict selection of indications may be the most effective measures to prevent arrhythmias after transcatheter closure of PMVSDs in patients under 18 years of age.