Mitochondrial Dysfunction Is the Focus of Quaternary Ammonium Surfactant Toxicity to Mammalian Epithelial Cells

Surfactants have long been known to have microbicidal action and have been extensively used as antiseptics and disinfectants for a variety of general hygiene and clinical purposes. Among surfactants, quaternary ammonium compounds (QAC) are known to be the most useful antiseptics and disinfectants. However, our previous toxicological studies showed that QAC are also the most toxic surfactants for mammalian cells. An understanding of the mechanisms that underlie QAC toxicity is a crucial first step in their rational use and in the design and development of more effective and safer molecules. We show that QAC-induced toxicity is mediated primarily through mitochondrial dysfunction in mammalian columnar epithelial cell cultures in vitro. Toxic effects begin at sublethal concentrations and are characterized by mitochondrial fragmentation accompanied by decreased cellular energy charge. At very low concentrations, several QAC act on mitochondrial bioenergetics through a common mechanism of action, primarily by inhibiting mitochondrial respiration initiated at complex I and, to a lesser extent, by slowing down coupled ADP phosphorylation. The result is a reduction of cellular energy charge which, when reduced below 50% of its original value, induces apoptosis. The lethal effects are shown to be primarily a result of this process. At higher doses (closer to the critical micellar concentration), QAC induce the complete breakdown of cellular energy charge and necrotic cell death.     

AHSP and β-thalassemia: A possible genetic modifier

The identification of defectives genes underlying inherited diseases has made it clear that patients with the same genotype can have variable clinical expression. Suggestions proposing that the protein AHSP, a a-globin specific chaperone could influence disease severity in patients with ß-thalassemia, an inherited disorder characterized by a quantitative deficiency of ß-globin genes. This article presents a review of the AHSP gene structure, function and expression. A discussion of the AHSP gene knowledgments is presented with an overview of the possible genetic modifier function of AHSP on ß-thalassemia pathophisiology.     

Real‐time motion correction for high‐resolution larynx imaging

Motion—both rigid‐body and nonrigid—is the main limitation to in vivo, high‐resolution larynx imaging. In this work, a new real‐time motion compensation algorithm is introduced. Navigator data are processed in real time to compute the displacement information, and projections are corrected using phase modulation in k‐space. Upon automatic feedback, the system immediately reacquires the data most heavily corrupted by nonrigid motion, i.e., the data whose corresponding projections could not be properly corrected. This algorithm overcomes the shortcomings of the so‐called diminishing variance algorithm by combining it with navigator‐based rigid‐body motion correction. Because rigid‐body motion correction is performed first, continual bulk motion no longer impedes nor prevents the convergence of the algorithm. Phantom experiments show that the algorithm properly corrects for translations and reacquires data corrupted by nonrigid motion. Larynx imaging was performed on healthy volunteers, and substantial reduction of motion artifacts caused by bulk shift, swallowing, and coughing was achieved. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

Fast concomitant gradient field and field inhomogeneity correction for spiral cardiac imaging

Non‐Cartesian imaging provides many advantages in terms of flexibility, functionality, and speed. However, a major drawback to these imaging methods is off‐resonance distortion artifacts. These artifacts manifest as blurring in spiral imaging. Common techniques that remove the off‐resonance field inhomogeneity distortion effects are not sufficient, because the high order concomitant gradient fields are nontrivial for common imaging conditions, such as imaging 5 cm off isocenter in an 1.5 T scanner. Previous correction algorithms are either slow or do not take into account the known effects of concomitant gradient fields along with the field inhomogeneities. To ease the correction, the distortion effects are modeled as a non‐stationary convolution problem. In this work, two fast and accurate postgridding algorithms are presented and analyzed. These methods account for both the concomitant field effects and the field inhomogeneities. One algorithm operates in the frequency domain and the other in the spatial domain. To take advantage of their speed and accuracy, the algorithms are applied to a real‐time cardiac study and a high‐resolution cardiac study. Both of the presented algorithms provide for a practical solution to the off‐resonance problem in spiral imaging. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

X-linked insertion/deletion polymorphisms: forensic applications of a 33-markers panel

Insertion/deletion (INDEL) polymorphisms are diallelic markers with potential characteristics for use in forensics and biological anthropology, including: the simplicity of laboratory analysis, the possibility of genotyping many markers in a single PCR multiplex reaction, as well as analyzing markers with special inheritance types, such as those linked to the X chromosome (X-INDEL). In this work we developed a laboratory analysis methodology using a 33-INDEL marker panel for the X chromosome in a single PCR multiplex reaction, followed by a capillary electrophoresis run. We employed the panel to genotype a sample of 351 individuals of a mixed population from the Brazilian Amazon. The results demonstrate that the measurement of biostatistical parameters for forensic use in this population is compatible with prior estimates from other populations using current X-STR panels.     

Birth weight and adult bone mass: a systematic literature review

Summary  

This systematic literature review comprised 16 studies. The association of birth weight with bone parameters was much more evident for bone mineral content (BMC) rather than bone mineral density (BMD). This is an important finding since a reduction in BMC is strongly associated with an increased risk of fractures.     

Síndrome PFAPA

PFAPA syndrome is characterized by periodic fever, pharyngitis, cervical adenitis and aphthous stomatitis. The bouts of fever can last for days or even weeks. Between crises, patients remain asymptomatic for variable periods. It appears before the age of five and has limited duration (4-8 years). Its aetiopathogeny is unknown. Corticoids are the treatment of choice. Tonsillectomy has been proposed as a solution but remains controversial. We present the case of a 4-year-old girl with PFAPA syndrome who underwent tonsillectomy in January, 2008, and we review the literature.