Microarray application in prenatal diagnosis: a position statement from the cytogenetics working group of the Italian Society of Human Genetics (SIGU), November 2011

A precise guideline establishing chromosomal microarray analysis (CMA) applications and platforms in the prenatal setting does not exist. The controversial question is whether CMA technologies can or should soon replace standard karyotyping in prenatal diagnostic practice. A review of the recent literature and survey of the knowledge and experience of all members of the Italian Society of Human Genetics (SIGU) Committee were carried out in order to propose recommendations for the use of CMA in prenatal testing. The analysis of datasets reported in the medical literature showed a considerable 6.4% incidence of pathogenic copy number variations (CNVs) in the group of pregnancies with sonographically detected fetal abnormalities and normal karyotype. The reported CNVs are likely to have a relevant role in terms of nosology for the fetus and in the assessment of reproductive risk for the couple. Estimation of the frequency of copy number variations of uncertain significance (VOUS) varied depending on the different CMA platforms used, ranging from 0-4%, obtained using targeted arrays, to 9-12%, obtained using high-resolution whole genome single nucleotide polymorphism (SNP) arrays. CMA analysis can be considered a second-tier diagnostic test to be used after standard karyotyping in selected groups of pregnancies, namely those with single (apparently isolated) or multiple ultrasound fetal abnormalities, those with chromosomal rearrangements, even if apparently balanced, and those with supernumerary marker chromosomes.     

Motor unit synchronous firing as revealed by determinism of surface myoelectric signal

Information on motor strategies can be extracted from the surface electromyogram (EMG) by non-linear methods. The percentage of determinism (%DET) obtained from recurrence quantification analysis (RQA) may be a sensitive variable to detect synchronous motor unit behaviour. The purpose of the present study was to validate this methodology by comparing it with an established technique estimating the degree of synchronization of pairs of voluntary activated motor units from the correlation of their firing in the time-domain. Single motor unit activity was recorded in extensor carpi radialis (ECR) muscle by pairs of tungsten microelectrodes inserted into the muscle belly. Cross-correlation analysis was performed in order to determine synchronization peak area by computing synchronous impulse probability. Surface EMG activity was recorded in parallel by electrodes placed over the skin of the same muscle and %DET was used as a measure of synchronous activity. The %DET appeared to be a valid measure of synchronization yielding results comparable to those obtained with cross-correlation analysis. Increases in %DET (t = 64.59, P < 0.0001) highly correlated (r2 = 0.70, P = 0.0013) with pharmacologically induced increases in the synchronization activity of pairs of ECR motor units (t = 8.71, P < 0.0001). RQA may be used as an alternative methodology for testing synchronous motor unit behaviour from surface EMG under physiological and pathological conditions.     

Torque Teno Virus—Cause of Viral Liver Disease Following Liver Transplantation: A Case Report

Torque Teno Virus (TTV), a nonenveloped human virus of the Circoviridae family, is hepatotropic, causing liver damage, cirrhosis, and, rarely, fulminant hepatitis. It prevails in 10% to 75% of blood donors due to environmental differences, independent of chronic hepatitis B virus (HBV)/HCV hepatitis, cryptogenic cirrhosis, alcoholic cirrhosis, and in fulminant hepatitis non-A-G. Reports about the efficacy of clinical alpha interferon are rare. In July 2007, a 65-year-old man who was serologically negative for A-E viruses presented with acute liver failure due to a ruptured hepatic artery aneurysm and underwent orthotopic liver transplantation (OLT). Immunosuppression was based on cyclosporine and steroids. At postoperative day 20, there was persistent hypertransaminasemia with otherwise normal liver function. A percutaneous hepatic biopsy documented pattern suggestive of a viral etiology. Multiple tests for hepatotropic viruses in the donor and the recipient from the pre- and post-OLT periods remained negative. Only the TTV qualitative test, assessed by polymerase chain reaction (PCR) on patient sera, was positive. Immunosuppressive therapy was not changed; no antiviral therapy was undertaken. At 6 months posttransplantation, transaminase levels spontaneously normalized and the clinical situation was unchanged. No complications were observed; the patient is in good clinical condition. No graft rejection was observed. In histologically proven non-A-E viral hepatitis, it is important to consider TTV as an incidental pathogenic agent. It may be useful to extend virological tests to TTV among transplant recipients and donors and to gain further knowledge about this virus.     

Early repolarization syndrome and Brugada syndrome: is there any linkage?

Early repolarization syndrome (ERS) is characterized by the presence, in most cases in mid-to-lateral precordial leads, of a J wave on the downsloping portion of the QRS complex, followed by an elevation of the ST-segment with upward concavity. ERS is considered a benign electrocardiographic pattern of ventricular repolarization and, thus far, clinical interest in this syndrome has been confined to its differential diagnosis from myocardial infarction and pericarditis. Brugada syndrome (BS), an inherited cardiac disease first described in 1992, exhibits a characteristic electrocardiographic pattern consisting of a J wave mimicking a right bundle branch block with typical ST-segment elevation in the right precordial leads. Believed to be a normal repolarization variant for more than three decades, the syndrome is now known instead to be associated with a high incidence of life-threatening ventricular tachyarrhythmias and is responsible for a number of sudden deaths in young adults worldwide. Although clinical findings seem to differentiate the two syndromes, similarities between BS and ERS in terms of response to heart rate, pharmacologic agents, and neuromodulation could suggest a linkage in their pathophysiological mechanism. The authors review the clinical and experimental data in order to test this hypothesis.     

Fluconazole Susceptibility in Cryptococcus gattii Is Dependent on the ABC Transporter Pdr11

Cryptococcus gattii isolates from the Pacific Northwest have exhibited higher fluconazole MICs than isolates from other sites. The mechanism of fluconazole resistance in C. gattii is unknown. We sought to determine the role of the efflux pumps Mdr1 and Pdr11 in fluconazole susceptibility. Using biolistic transformation of the parent isolate, we created a strain lacking Mdr1 (mdr1Δ) and another strain lacking Pdr11 (pdr11Δ). Phenotypic virulence factors were assessed by standard methods (capsule size, melanin production, growth at 30 and 37°C). Survival was assessed in an intranasal murine model of cryptococcosis. Antifungal MICs were determined by the M27-A3 methodology. No differences in key virulence phenotypic components were identified. Fluconazole susceptibility was unchanged in the Mdr1 knockout or reconstituted isolates. However, fluconazole MICs decreased from 32 μg/ml for the wild-type isolate to <0.03 μg/ml for the pdr11Δ strain and reverted to 32 μg/ml for the reconstituted strain. In murine models, no difference in virulence was observed between wild-type, knockout, or reconstituted isolates. We conclude that Pdr11 plays an essential role in fluconazole susceptibility in C. gattii. Genomic and expression differences between resistant and susceptible C. gattii clinical isolates should be assessed further in order to identify other potential mechanisms of resistance.     

Tetrahydrofuran as solvent in dental adhesives: cytotoxicity and dentin bond stability

Objectives

The aim of this study was to investigate the cytotoxicity and 1-year dentin bond stability of solvated etch-and-rinse dental adhesives based on tetrahydrofuran (THF), acetone, or ethanol, containing water or not.

Materials and methods

Seven primers were prepared using the following solvents: THF, acetone, ethanol, water, THF/water, acetone/water, and ethanol/water. Bovine dentin was used, and specimens for microtensile bond strength (μTBS) test were prepared. Specimens were tested after storage in distilled water for 24 h or 1 year. Cytotoxicity of the solvents was evaluated in 3T3/NIH mouse fibroblasts using a colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay after exposure for 24 h.

Results

No significant differences were detected among solvents after storage for 24 h, except for the water-based group, which showed the lowest μTBS values. After storage for 1 year, the THF-based adhesive system resulted in more stable bonds. Yet, THF showed an intermediate cytotoxicity when compared with the other solvents, being less toxic than phosphate monomer and similar to 2-hydroxyethyl methacrylate.

Conclusion

THF seems to be a suitable solvent for adhesive systems.

Clinical relevance

THF is a promising solvent that can be used to improve dentin bond stability.     

Proton pump inhibitors: Risks of long‐term use

Proton pump inhibitors are among the most commonly prescribed classes of drugs, and their use is increasing, in particular for long‐term treatment, often being over‐prescribed and used for inappropriate conditions. In recent years, considerable attention has been directed towards a wide range of adverse effects, and even when a potential underlying biological mechanism is plausible, the clinical evidence of the adverse effect is often weak. Several long‐term side effects have been investigated ranging from interaction with other drugs, increased risk of infection, reduced intestinal absorption of vitamins and minerals, and more recently kidney damage and dementia. The most recent literature regarding these adverse effects and their association with long‐term proton pump inhibitor treatment is reviewed, and the mechanisms through which these possible complications might develop are discussed.