IAPS includes photographs that elicit low-arousal physiological responses in healthy volunteers

This article describes pleasant IAPS pictures that elicit low-arousal rather than the high-arousal physiological responses previously reported in the literature. Thirty-two International Affective Picture System (IAPS) photographs were grouped into 4 sets of 8 photographs: highly pleasant-arousing (sexual content and adventures), highly pleasant-relaxing pictures (landscapes, flowers or babies), neutral on both valence/arousal, and highly unpleasant-arousing ones. These stimuli were shown to 24 healthy Brazilian University students (12 males) who had their physiological responses recorded [corrugator and zygomatic facial electromyography activity, skin conductance, heart rate, and peripheral temperature]. Zygomatic EMG differentiated low-arousal pleasant photographs from high-arousal pleasant stimuli of the same valence.     

Whole-blastocyst culture followed by laser drilling technology enhances the efficiency of inner cell mass isolation and embryonic stem cell derivation from good- and poor-quality mouse embryos: new insights for derivation of human embryonic stem cell lines

The optimization of human embryonic stem (hES) cell line derivation methods is challenging because many worldwide laboratories have neither access to spare human embryos nor ethical approval for using supernumerary human embryos for hES cell derivation purposes. Additionally, studies performed directly on human embryos imply a waste of precious human biological material. In this study, we developed a new strategy based on the combination of whole-blastocyst culture followed by laser drilling destruction of the trophoectoderm for improving the efficiency of inner cell mass (ICM) isolation and ES cell derivation using murine embryos. Embryos were divided into good- and poor-quality embryos. We demonstrate that the efficiency of both ICM isolation and ES cell derivation using this strategy is significantly superior to whole-blastocyst culture or laser drilling technology itself. Regardless of the ICM isolation method, the ES cell establishment depends on a feeder cell growth surface. Importantly, this combined methodology can be successfully applied to poor-quality blastocysts that otherwise would not be suitable for laser drilling itself nor immunosurgery in an attempt to derive ES cell lines due to the inability to distinguish the ICM. The ES cell lines derived by this combined method were characterized and shown to maintain a typical morphology, undifferentiated phenotype, and in vitro and in vivo three germ layer differentiation potential. Finally, all ES cell lines established using either technology acquired an aneuploid karyotype after extended culture periods, suggesting that the method used for ES cell derivation does not seem to influence the karyotype of the ES cells after extended culture. This methodology may open up new avenues for further improvements for the derivation of hES cells, the majority of which are derived from frozen, poor-quality human embryos.     

Virulent Salmonella enterica serovar typhimurium evades adaptive immunity by preventing dendritic cells from activating T cells

Dendritic cells (DCs) constitute the link between innate and adaptive immunity by directly recognizing pathogen-associated molecular patterns (PAMPs) in bacteria and by presenting bacterial antigens to T cells. Recognition of PAMPs renders DCs as professional antigen-presenting cells able to prime na?ve T cells and initiate adaptive immunity against bacteria. Therefore, interfering with DC function would promote bacterial survival and dissemination. Understanding the molecular mechanisms that have evolved in virulent bacteria to evade activation of adaptive immunity requires the characterization of virulence factors that interfere with DC function. Salmonella enterica serovar Typhimurium, the causative agent of typhoid-like disease in the mouse, can prevent antigen presentation to T cells by avoiding lysosomal degradation in DCs. Here, we show that this feature of virulent Salmonella applies in vivo to prevent activation of adaptive immunity. In addition, this attribute of virulent Salmonella requires functional expression of a type three secretion system (TTSS) and effector proteins encoded within the Salmonella pathogenicity island 2 (SPI-2). In contrast to wild-type virulent Salmonella, mutant strains carrying specific deletions of SPI-2 genes encoding TTSS components or effectors proteins are targeted to lysosomes and are no longer able to prevent DCs from activating T cells in vitro or in vivo. SPI-2 mutant strains are attenuated in vivo, showing reduced tissue colonization and enhanced T-cell activation, which confers protection against a challenge with wild-type virulent Salmonella. Our data suggest that impairment of DC function by the activity of SPI-2 gene products is crucial for Salmonella pathogenesis.     

Comparative analyses of the neurodegeneration induced by the non-competitive NMDA-receptor-antagonist drug MK801 in mice and rats

Non-competitive NMDA-receptor-antagonist drugs such as dizocilpine (MK801) induce behavioral changes and neurotoxicity that have made an impact in different fields of neuroscience. New approaches in research use transgenic mice to elucidate cellular mechanisms and circuits involved in the effects of these drugs. However, the neurodegeneration induced by these drugs has been extensively studied in rats, but the data in mice is limited. Therefore it is important to characterize if the neurotoxic pattern in mice corresponds to that of rats.A comparative analysis of the neurodegeneration induced by MK801 (10 mg/kg) between Wistar rats, and CD-1, CF-1, and C57BL/6-129/Sv mice of both sexes, at different survival times (15, 24, 32, 48, 56 and 72 h) was analysed with the amino-cupric-silver and fluoro-jade B techniques. To compare different administration patterns, groups of mice received subchronic treatments with different doses (final doses of 20 and 40 mg/kg).Results showed that mice treated with MK801 presented different neurotoxic profiles, such as excitotoxic-like cell death in the retrosplenial cortex, terminal degeneration in CA1 and apoptotic-like degeneration in the olfactory bulb. Unlike rats, mice subjected to the same treatment failed to show neurodegeneration in corticolimbic areas such as piriform cortex and dentate gyrus. The amount of degeneration was lower in mice, and the subchronic administration of MK801 did not change the neurotoxic pattern. Additionally, mice lacked the sexually dimorphic response to MK801 toxicity observed in rats. Altogether these results indicate important species dissimilarities. Neurotoxicological studies aimed to explore pathways and mechanisms of MK801 toxicity should consider these differences when using mice as rodent models.     

Mallory-Weiss syndrome as etiologic factor of upper gastrointestinal hemorrhage. A review of 142 cases

The diagnosis of Mallory-Weiss syndrome was made in 142 patients with upper gastrointestinal haemorrhage by early endoscopy. These patients represent 5.16% of all patients with haemorrhage treated in our unit over a period of ten years. Emergency surgery was needed in 13 due to persistent haemorrhage. In the remaining 129, conservative management sufficed to stop the bleeding. All patients receiving medical therapy survived while one of the surgically treated patients died of pulmonary thromboembolism in the early postoperative period.     

Influence of Single-file Endodontics on Apical Transportation in Curved Root Canals: An Ex Vivo Micro–Computed Tomographic Study

Introduction

More information regarding the ability of single files to maintain the original canal position is required before adopting a single-file approach to cleaning and shaping. This study compares apical transportation in curved root canals when instrumenting with a single WaveOne (WO) file (Dentsply Tulsa Dental Specialties, Tulsa, OK) in a reciprocating motion with that incurred when using a sequence of Twisted Files (TFs; SybronEndo, Orange, CA) in a continuous rotating motion.

Methods

Forty mesial canals of mandibular molars were evenly allocated into 2 balanced groups (n = 20) with a 17-mm average canal length and 20° average curvature. Canals were accessed in a conventional manner and instrumentation was completed with a single WO file or a series of TFs. The canals were instrumented according to the manufacturers' protocol. Apical transportation was assessed on a comparison of the pre- and postinstrumentation micro–computed tomographic scans at 1-, 2-, 3-, 4-, and 5-mm sections. One-way analysis of variance was performed to assess if a significant difference between systems exists.

Results

No significant difference (P > .05) was found between the WO and TF groups. Transportation in the mesial direction was of greater magnitude than distal transportation for both files systems. The mean transportation in the mesial direction was 100.1 ± 8.8 μm (WO group) and 101.0 ± 10.9 μm (TF group) (P = .5), whereas distal transportation was found to be 80.9 ± 14.6 μm (WO group) and 60.3 ± 11.0 μm (TF group) (P = .3).

Conclusions

The results suggest that no difference exists between the WO file system and the conventional multifile TF system when considering apical transportation in curved canals.     

Effective Analysis of the Use of Peracetic Acid after Instrumentation of Root Canals Contaminated with Enterococcus faecalis

Introduction

The aim of this study was to evaluate the effectiveness of peracetic acid (PAA) in cleaning root canals contaminated with Enterococcus faecalis.

Methods

Sixty first and second mandibular molars were used. Their mesiobuccal canals were prepared with the Reciproc System (VDW, Munich, Germany). The canals were irrigated with 10 mL saline during instrumentation. The teeth were randomly divided into 3 groups (n = 20), according to the irrigation solution to be used after instrumentation: group PAA (5 mL 1% PAA), group EDTA/sodium hypochlorite (NaOCl) (5 mL 17% EDTA followed by 5 mL 2.5% sodium hypochlorite), and group S (5 mL saline). Microbiological samples were collected before instrumentation and after final irrigation. Bacterial quantification was performed by counting the number of colony-forming units (CFUs/mL). The results were analyzed by the nonparametric Wilcoxon and Kruskal-Wallis tests.

Results

The 3 groups showed a significant reduction (P < .05) in CFUs/mL after final irrigation. PAA and NaOCl associated with EDTA produced a significantly higher reduction in CFUs/mL (P < .05) compared with saline. There was no statistically significant difference between PAA and EDTA + 2.5% NaOCl (P > .05).

Conclusions

According to the results of the present study, the effectiveness of 1% PAA was similar to that of 17% EDTA + 2.5% NaOCl in cleaning curved root canals contaminated with E. faecalis.     

Role of liver transplantation in the management of metastatic neuroendocrine tumors

INTRODUCTION: In the majority of patients transplanted for unresectable liver metastases, long-term results are disappointing because of early tumor recurrence. Due to its biologically less aggressive nature, neuroendocrine metastases (NM) may represent a good indication for liver transplantation (LT). PATIENTS AND METHODS: Between January 1996 and May 2000, five patients with NM were transplanted. The primary tumors were located in the pancreas (n=4) and the small bowel (n=1). In three cases there were symptoms related to hormone production: two carcinoids, and one gastrinoma. The management of primary tumors was sequential in three patients with the tumor being resected before LT (one Whipple procedure and two left pancreatectomies). In two patients the resections of the primary tumors and the LT were simultaneous namely one bowel resection and one left pancreatectomy. All patients were treated with chemotherapy. RESULTS: Two patients developed recurrent disease succumbing at 15 months (nonfunctioning NE pancreatic head tumor) and 17 months (carcinoid of the pancreatic tail) post-LT. Another patient died at 3 months post-LT due to technical complications. The other two patients are alive and free of recurrence. CONCLUSION: Despite the promising results obtained with LT for NM, our experience indicates that patients must be carefully selected. Perhaps the use of more aggressive chemotherapeutic protocols combined with an individualized approach will improve the results.     

Ferrite particles for bowel contrast in MR imaging: design issues and feasibility studies

Diverse materials with varying physical and magnetic properties have been evaluated as gastrointestinal contrast agents for magnetic resonance (MR) imaging. Uniform marking of the small bowel remains the greatest challenge. Ferrites are magnetically active iron oxide particles that are miscible with water and cause loss of signal on MR images. The decrease in MR signal intensity produced by ferrites occurs with a wide range of iron concentrations (0.1-10 mM) and with both T1- and T2-weighted pulse sequences. These effects of ferrites are explained by predominant T2 shortening with negligible T1 effects. The ferrite preparation used in this study was stable in vitro, with little iron solubilized by acid. Intragastric administration of ferrite (5 mg of iron per kg in 6 ml) routinely marked the small bowel of rats. The authors conclude that ferrites represent a promising new class of contrast agents for gastrointestinal MR imaging.