Presence and characterization of extraintestinal pathogenic Escherichia coli virulence genes in F165-positive E. coli strains isolated from diseased calves and pigs

The virulence genotype profile and presence of a pathogenicity island(s) (PAI) were studied in 18 strains of F165-positive Escherichia coli originally isolated from diseased calves or piglets. On the basis of their adhesion phenotypes and genotypes, these extraintestinal pathogenic strains were classified into three groups. The F165 fimbrial complex consists of at least two serologically and genetically distinct fimbriae: F165(1) and F165(2). F165(1) is encoded by the foo operon (pap-like), and F165(2) is encoded by fot (sfa related). Strains in group 1 were foo and fot positive, strains in group 2 were foo and afa positive, and strains in group 3 were foo positive only. The strains were tested for the presence of virulence genes found mainly in extraintestinal pathogenic E. coli (ExPEC) strains. Although all the strains were positive for the papA variant encoding F11 fimbriae incD, traT, and papC, the prevalence of virulence genes commonly found in PAIs associated with ExPEC strains was highly variable, with strains of group 2 harboring most of the virulence genes tested. papG allele III was detected in all strains in group 1 and in one strain in group 3. All other strains were negative for the known alleles encoding PapG adhesins. The association of virulence genes with tRNA genes was characterized in these strains by using pulsed-field gel electrophoresis and DNA hybridization. The insertion site of the foo operon was found at the pheU tRNA locus in 16 of the 18 strains and at the selC tRNA locus in the other 2 strains. Furthermore, 8 of the 18 strains harbored a high-pathogenicity island which was inserted in either the asnT or the asnV/U tRNA locus. These results suggest the presence of one or more PAIs in septicemic strains from animals and the association of the foo operon with at least one of these islands. F165-positive strains share certain virulence traits with ExPEC, and most of them are pathogenic in piglets, as tested in experimental infections.     

Indirect functional assessment of stereotypy in children with autism spectrum disorders

Autism spectrum disorders (ASD) are characterized by the presence of repetitive behavior and stereotyped patterns of interest and activities. It is common for clinicians to assume that repetitive behaviors are maintained by automatic reinforcement but, as with any challenging behavior, the function of stereotypy should not be assumed based on its topography. Previous research on the functional assessment of stereotypy has produced mixed results, and most previous studies on the functional assessment of stereotypy in children with ASD have included small sample sizes, so more research in this area is warranted. In the current study, indirect functional assessments consisting of the questions about behavioral function (QABF) were conducted across 53 children and adolescents with ASD. The QABF produced interpretable results in a high percentage of cases and 90% of the stereotypic behavior appeared to be maintained by automatic reinforcement.     

Frequent Ventricular Premature Beats in Children With a Structurally Normal Heart: A Cause for Reversible Left Ventricular Dysfunction?

Ventricular premature beats (VPBs) in a structurally normal heart generally are a benign condition. Rarely, however, reversible cardiomyopathy may develop. This study aimed to evaluate the incidence of cardiomyopathy among pediatric patients in a cohort with frequent VPBs and to examine the characteristics of the ventricular ectopic beats as well as therapeutic options. This study reviewed the charts of all pediatric patients between the ages of 1 day and 18 years seen at the University of Kentucky with the diagnosis of VPBs between 2003 and 2007. Frequent VPBs were defined as an ectopy burden of 5% or more in 24 h. Electrocardiograms, Holter monitors, and echocardiograms were reviewed. The review identified 28 patients (17 boys, age 13.3 ± 5.9 years, and 11 girls, age 13 ± 5.2 years) with frequent VPBs. The echocardiograms of four patients (2 boys, 14%) showed cardiomyopathy. Cardiac function normalized in all four patients, with spontaneous resolution of the VPBs (2 patients) or with antiarrhythmic therapy (2 patients). During a follow-up period of 2.7 ± 2.3 years, 32% of the patients without cardiomyopathy showed a marked spontaneous improvement in arrhythmia burden. Most of the patients showed VPBs with a left bundle branch block (LBBB) and inferior axis morphology. The most commonly associated symptoms were chest pain (17.8%) and dizziness and syncope (21.4%). Generally, VPBs in structurally normal hearts are considered benign. Rarely, a reversible cardiomyopathy can develop, requiring therapeutic intervention.     

Complete occlusion of the left circumflex coronary artery after radiofrequency catheter ablation in an infant

Radiofrequency catheter ablation of a left lateral accessory atrioventricular pathway was performed in a 5-week-old infant with drug-refractory supraventricular tachycardia. Energy application via a 5-French mapping and ablation catheter in the temperature-controlled mode (60 degrees C, 30 W) at the atrial aspect of the mitral valve annulus repeatedly resulted in termination of the tachycardia by conduction block within the pathway. Tachycardia remained inducible subsequently. After a safety energy application during sinus rhythm, significant ST-segment elevation in the inferior, mid precordial, and left lateral leads was noted. Selective left coronary angiography revealed complete occlusion of the circumflex coronary artery. Moderate-to-severe mitral valve regurgitation developed, finally requiring mitral valve replacement.     

Evaluation of sperm DNA fragmentation and chromatin structure in infertile men with immotile short-tail sperm defect

Teratozoospermia is characterised by the presence of spermatozoa with abnormal morphology. One of the morphological disorders that lead to male infertility is immotile short-tail sperm (ISTS) defect. In this study, we evaluated the levels of chromatin packing and DNA fragmentation in patients with immotile short-tail sperm defect. Semen samples were obtained from 31 infertile men with ISTS as case group and 31 normozoospermic men as a control group. Protamine status was evaluated using chromomycin A3 (CMA3) staining and sperm DNA fragmentation assessed by sperm chromatin structure assay (SCSA) and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick-end labelling (TUNEL). The percentage of positive CMA3 spermatozoa was significantly higher in patients’ samples (22.6 ± 6.9) compared with controls (16.3 ± 4.2) (p < .05) and also mean (±SD) of sperm DNA fragmentation was significantly higher in patients compared with controls, as measured by TUNEL assay (10.45 ± 4.60 vs. 7.03 ± 2.86, p < .05) and SCSA (24.80 ± 13.1 vs. 15.2 ± 7.2, p < .05). According to our study, sperm DNA fragmentation and chromatin packing abnormality are significantly higher in the ISTS samples compared with normal samples. A possible explanation for this relationship is that sperm chromatin condensation and sperm flagellum formation occur during the same phase of spermatogenesis.     

Correlation of BRAF and NRAS mutation status with outcome,site of distant metastasis and response to chemotherapy in metastatic melanoma

Background:

The prognostic significance of BRAF and NRAS mutations in metastatic melanoma patients remains uncertain, with several studies reporting conflicting results, often biased by the inclusion of patients treated with BRAF and MEK (MAPK) inhibitors. We therefore interrogated a historical cohort of patients free of the confounding influence of MAPK inhibitor therapy.

Methods:

Patients with available archival tissue first diagnosed with metastatic melanoma between 2002 and 2006 were analysed. Mutational analysis was performed using the OncoCarta Panel. Patient characteristics, treatment outcome and survival were correlated with BRAF/NRAS mutation status.

Results:

In 193 patients, 92 (48%) melanomas were BRAF-mutant, 39 (20%) were NRAS-mutant and 62 (32%) were wild-type for BRAF/NRAS mutations (wt). There was no difference in response to chemotherapy based on mutation status (35–37%). The distant disease-free interval (DDFI) was significantly shorter in patients with wt melanoma (27.9 months vs 35.1 for BRAF and 49.1 for NRAS) although this was not significant in multivariate analysis. Survival from stage IV melanoma diagnosis was not significantly different based on mutation status. The DDFI was significantly shorter in patients with BRAF^V600K/R versus BRAF^V600E melanoma in univariate and multivariate analyses.

Conclusions:

BRAF and NRAS mutation status does not influence survival in metastatic melanoma.     

Surgical electrocautery facilitated transseptal puncture in children

Background: Transseptal puncture has been performed in adults and children for decades. However, transseptal puncture can be challenging especially in pediatric patients because of an elastic septum and small atria. In adults, dedicated radiofrequency (RF) to facilitate transseptal puncture has become routine. Objectives: We wanted to assess whether RF could be used routinely in children to facilitate transseptal procedure. Method: The study population included all children referred to our electrophysiology lab who underwent an ablation requiring a transseptal puncture over a period of 10 months. RF was applied at the time of transseptal puncture. The source of RF was standard surgical electrocautery device with the electrosurgical pen in direct contact with the transseptal needle applied for a short period of time during transseptal puncture. RF output was set initially at 30 W in cut mode. All procedures were performed under general anesthesia. Patients were followed for possible complications. Results: Thirteen patients (ages 11.6 ± 3.6 years, range 5–17 years, five boys) were included. One patient had left ventricular tachycardia, and the remainder had a supraventricular tachycardia with a left‐sided accessory pathway. In all but two patients, a single attempt with an RF output of 30 W applied for less than 2 seconds was sufficient to cross the septum. In two patients, three attempts were needed with a last successful attempt using 35 W. No complications were observed either acutely or during the follow‐up. Conclusion: Transseptal puncture facilitated by RF energy can be performed in children routinely and safely. (PACE 2011; 34:827–831)     

Epithelial RNase H2 Maintains Genome Integrity and Prevents Intestinal Tumorigenesis in Mice

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