Prävalenz des Komplexen Schlafapnoesyndroms

Das Komplexe Schlafapnoesyndrom (CompSAS) bezeichnet das Auftreten von 5 oder mehr zentralen Apnoen pro Stunde unter ansonsten effizienter nCPAP-Therapie bei Patienten mit obstruktiver Schlafapnoe. Wir führten eine prospektive Studie durch, um Patienten mit CompSAS zu identifizieren und den Verlauf nach 3 Monaten zu beobachten. Von 675 Patienten entwickelten 82 (12,2%) CompSAS. Nach 3 Monaten zeigten nur 30 von 436 bei Therapiekontrolle verfügbaren Patienten (6,9%) ein CompSAS. Von den 54 Patienten mit initialem CompSAS hatten bei Therapiekontrolle 40 (74%) kein CompSAS mehr. 16 von 382 Patienten (4,2%) ohne initialem CompSAS wiesen bei Therapiekontrolle CompSAS auf. Dieses Ergebins stellt das CompSAS als stabiles Krankheitsbild in Frage

Analysis of R213R and 13494 g→a polymorphisms of the p53 gene in individuals with esophagitis, intestinal metaplasia of the cardia and Barrett’s Esophagus compared with a control group

Protein p53 is the tumor suppressor involved in cell cycle control and apoptosis. There are several polymorphisms reported for p53 which can affect important regions involved in protein tumor suppressor activity. Amongst the polymorphisms described, R213R and 13949 g→a are rarely studied, with an estimate frequency not yet available for the Brazilian population. The purpose of this study was to investigate the genotype and allele frequencies and associations of these polymorphisms in a group of patients with altered esophageal tissue from South Brazil and compare with the frequency observed for a control population. A total of 35 patients for R213R and 45 for 13494 g→a polymorphisms analysis with gastroesophageal reflux disease (GERD) symptoms diagnosed by upper digestive endoscopy and confirmed by biopsy were studied. For both groups, 100 controls were used for comparison. Loss of heterozygosity (LOH) was also analyzed for a selected group of patients where normal and affected tissue was available. There was one patient with Barrett’s Esophagus (BE) showing LOH for R213R out of two heterozygous samples analyzed and two patients (esophagitis and BE) for 13494 g→a polymorphism. We also aimed to build a haplotype for both polymorphisms collectively analyzed with R27P polymorphism, previously reported by our group. There were no significant differences in allele and genotype distribution between patients and controls. Although using esophagitis, intestinal metaplasia of the cardia and BE samples, all non-neoplastic lesions, we can conclude that these sites do not represent genetic susceptibility markers for the development and early progression of GERD to BE and esophageal cancer. Additional studies are required in order to investigate other determiners of early premalignant lesions known to predispose to esophageal cancer

Protocolos laboratoriais de análise molecular para investigação de doenças genéticas

The application of molecular analysis in the investigation of genetic diseases has been used as routine evaluation in laboratories worldwide in the last decade. More recently, the identification of specific mutations responsible for hereditary disorders made molecular diagnosis quicker and more efficient, making this analysis an excellent tool for the diagnosis of many diseases. Several techniques can be used and, among them, the Polymerase Chain Reaction (PCR) was a mark in the “molecular era”. In the last few years, the procedures have been automated gradually, which will allow the realization of a greater number of tests in a limited amount of time. The use of knowledge in Molecular Biology Techniques has been applied in many fields of Medicine. The advances made in the last decade demonstrate a huge potential of these technologies, which can be used not only for diagnosis, but also for treatment and prevention of hereditary disorders. The perspectives for the new century are very promising and indicate the possibility of great advances in the treatment of genetic diseases. The present article describes the main techniques used in the molecular analysis for the investigation of genetic diseases.A aplicação da análise molecular na investigação de doenças genéticas começou a ser utilizada como avaliação rotineira em laboratórios no decorrer da última década. Mais recentemente, a identificação de mutações específicas responsáveis por doenças hereditárias tornou o diagnóstico molecular mais rápido e eficaz, fazendo desta análise uma ótima ferramenta para diagnóstico de muitas destas doenças. Diversas técnicas laboratoriais são utilizadas para a análise molecular de doenças genéticas. Dentre estas destaca-se a reação em cadeia da polimerase (Polymerase Chain Reaction - PCR), que foi um marco na “era molecular”. Nos últimos anos, os procedimentos vem sendo automatizados gradativamente, o que irá propiciar a realização de maior número de testes num curto espaço de tempo. O uso dos conhecimentos da Biologia Molecular vem sendo aplicado nas mais variadas áreas da Medicina. No campo da genética molecular, os avanços das últimas décadas demostram um enorme potencial desta tecnologia, que pode ser utilizada não somente no diagnóstico mas também no tratamento e prevenção de doenças hereditárias. As perspectivas para o novo século são bastante promissoras e indicam a possibilidade de grandes avanços no tratamento de doenças. O presente artigo descreve as principais técnicas de análise molecular utilizadas para a investigação de doenças genéticas

Lack of association between the Serotonin Transporter Promoter Polymorphism (5-HTTLPR) and Panic Disorder: a systematic review and meta-analysis

<p>Abstract</p> <p>Background</p> <p>The aim of this study is to assess the association between the Serotonin Transporter Promoter Polymorphism (5-HTTLPR) and Panic Disorder (PD).</p> <p>Methods</p> <p>This is a systematic review and meta-analysis of case-control studies with unrelated individuals of any ethnic origin examining the role of the 5-HTTLPR in PD according to standard diagnostic criteria (DSM or ICD). Articles published in any language between January 1996 and April 2007 were eligible. The electronic databases searched included PubMed, PsychInfo, Lilacs and ISI. Two separate analyses were performed: an analysis by alleles and a stratified analysis separating studies by the quality of control groups. Asymptotic DerSimonian and Laird's Q test were used to assess heterogeneity. Results of individual studies were combined using the fixed effect model with respective 95% confidence intervals.</p> <p>Results</p> <p>Nineteen potential articles were identified, and 10 studies were included in this meta-analysis. No statistically significant association between 5-HTTLPR and PD was found, OR = 0.91 (CI95% 0.80 to 1.03, p = 0.14). Three sub-analyses divided by ethnicity, control group quality and Agoraphobia comorbidity also failed to find any significant association. No evidence of heterogeneity was found between studies in the analyses.</p> <p>Conclusion</p> <p>Results from this systematic review do not provide evidence to support an association between 5-HTTLPR and PD. However, more studies are needed in different ethnic populations in order to evaluate a possible minor effect.</p

Prevalence of thrombophilia and thrombotic events in patients with fabry disease in a Reference Center for Lysosomal Disorders in Southern Brazil

Introduction: Venous thromboembolism (VTE) is a multifactorial genetic disorder that occurs in approximately one in a thousand adults per year. Because there is no laboratory test or clinical marker useful for predicting which patients with Fabry disease may develop thrombotic events, this study aimed to determine whether there is a hereditary predisposition to hypercoagulation in these patients. Methods: The prevalence of p.R506Q mutation in the factor V gene and of c.G20210A mutation in Factor II (prothrombin) gene was evaluated in 39 patients with Fabry disease from Southern Brazil and correlated with clinical findings. The DNA analysis was performed by real-time polymerase chain reaction on genomic DNA using TaqMan probes. Results: In this group of patients, the frequency of mutation in the prothrombin gene was 1.28%, whereas no patient showed mutation in the factor V gene; additionally, there was no correlation between these mutations and the incidence of thrombotic events. Conclusion: Hereditary thrombophilia due to mutations in factor V and prothrombin genes does not seem to be related to thrombotic events in Fabry patients in our cohort, although studies in larger cohorts and the inclusion of additional factors may be required to determine if a correlation exists

Detection of mosaic variants in mothers of MPS II patients by next generation sequencing

Mucopolysaccharidosis type II is an X-linked lysosomal storage disorder caused by mutations in the IDS gene that encodes the iduronate-2-sulfatase enzyme. The IDS gene is located on the long arm of the X-chromosome, comprising 9 exons, spanning approximately 24 kb. The analysis of carriers, in addition to detecting mutations in patients, is essential for genetic counseling, since the risk of recurrence for male children is 50%. Mosaicism is a well-known phenomenon described in many genetic disorders caused by a variety of mechanisms that occur when a mutation arises in the early development of an embryo. Sanger sequencing is limited in detecting somatic mosaicism and sequence change levels of less than 20% may be missed. The Next Generation Sequencing (NGS) has been increasingly used in diagnosis. It is a sensitive and fast method for the detection of somatic mosaicism. Compared to Sanger sequencing, which represents a cumulative signal, NGS technology analyzes the sequence of each DNA read in a sample. NGS might therefore facilitate the detection of mosaicism in mothers of MPS II patients. The aim of this study was to reanalyze, by NGS, all MPS II mothers that showed to be non-carriers by Sanger analysis. Twelve non-carriers were selected for the reanalysis on the Ion PGM and Ion Torrent S5 platform, using a custom panel that includes the IDS gene. Results were visualized in the Integrative Genomics Viewer (IGV). We were able to detected the presence of the variant previously found in the index case in three of the mothers, with frequencies ranging between 13 and 49% of the reads. These results suggest the possibility of mosaicism in the mothers. The use of a more sensitive technology for detecting low-level mosaic mutations is essential for accurate recurrence-risk estimates. In our study, the NGS analysis showed to be an effective methodology to detect the mosaic event

Control of Positive and Negative Magnetoresistance in Iron Oxide : Iron Nanocomposite Thin Films for Tunable Magnetoelectric Nanodevices

The perspective of energy-efficient and tunable functional magnetic nanostructures has triggered research efforts in the fields of voltage control of magnetism and spintronics. We investigate the magnetotransport properties of nanocomposite iron oxide/iron thin films with a nominal iron thickness of 5-50 nm and find a positive magnetoresistance at small thicknesses. The highest magnetoresistance was found for 30 nm Fe with +1.1% at 3 T. This anomalous behavior is attributed to the presence of Fe3O4-Fe nanocomposite regions due to grain boundary oxidation. At the Fe3O4/Fe interfaces, spin-polarized electrons in the magnetite can be scattered and reoriented. A crossover to negative magnetoresistance (-0.11%) is achieved at a larger thickness (>40 nm) when interface scattering effects become negligible as more current flows through the iron layer. Electrolytic gating of this system induces voltage-triggered redox reactions in the Fe3O4 regions and thereby enables voltage-tuning of the magnetoresistance with the locally oxidized regions as the active tuning elements. In the low-magnetic-field region (<1 T), a crossover from positive to negative magnetoresistance is achieved by a voltage change of only 1.72 V. At 3 T, a relative change of magnetoresistance about -45% during reduction was achieved for the 30 nm Fe sample. The present low-voltage approach signifies a step forward to practical and tunable room-temperature magnetoresistance-based nanodevices, which can boost the development of nanoscale and energy-efficient magnetic field sensors with high sensitivity, magnetic memories, and magnetoelectric devices in general. Copyright © 2020 American Chemical Society

Mutation analysis in South American patients with Mucopolysaccharidosis type I

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder due to the deficiency of-L-iduronidase (IDUA). Severely affected patients show coarse faces, hepatosplenomegaly and mental retardation. Mild cases have facial features, joint stiffness, short stature but no CNS involvement. The gene encoding IDUA was cloned in 1990 and more than 55 disease-causing mutations have been described so far. Mutation frequency varies worldwide but W402X is the most frequent mutation found in European patients. A group of 56 MPS I patients, 25 from Argentina and 31 from Brazil, were genotyped. By analyzing ten recurrent mutations we were able to define 76% of the Argentinean alleles and 60% of the genotypes. For the Brazilian group, 62% of the alleles and 45% of the genotypes were assigned by the analysis of these same ten mutations. Sequencing of Brazilian patients led to the discovery of 13 new mutations and 4 new ones were found in Argentineans. The two most frequent mutations in both populations were W402X and P533R. The number of alleles bearing private mutations in Argentinean patients was 3 out of 50 and among the Brazilians, 16 out of 58. Such genetic heterogeneity is a concern when analyzing patients from miscigenated populations, such as South American countries.Asociación de Antropología Biológica de la República Argentin

Control of positive and negative magnetoresistance in iron oxide−iron nanocomposite thin films for tunable magnetoelectric nanodevices

The perspective of energy-efficient and tunable functional magnetic nanostructures has triggered research efforts in the fields of voltage control of magnetism and spintronics. We investigate the magnetotransport properties of nanocomposite iron oxide/iron thin films with a nominal iron thickness of 5-50 nm and find a positive magnetoresistance at small thicknesses. The highest magnetoresistance was found for 30 nm Fe with +1.1% at 3 T. This anomalous behavior is attributed to the presence of Fe3O4-Fe nanocomposite regions due to grain boundary oxidation. At the Fe3O4/Fe interfaces, spin-polarized electrons in the magnetite can be scattered and reoriented. A crossover to negative magnetoresistance (−0.11%) is achieved at a larger thickness (>40 nm) when interface scattering effects become negligible as more current flows through the iron layer. Electrolytic gating of this system induces voltage-triggered redox reactions in the Fe3O4 regions and thereby enables voltage-tuning of the magnetoresistance with the locally oxidized regions as the active tuning elements. In the low-magnetic-field region (<1 T), a crossover from positive to negative magnetoresistance is achieved by a voltage change of only 1.72 V. At 3 T, a relative change of magnetoresistance about −45% during reduction was achieved for the 30 nm Fe sample. The present low-voltage approach signifies a step forward to practical and tunable room-temperature magnetoresistance-based nanodevices, which can boost the development of nanoscale and energy-efficient magnetic field sensors with high sensitivity, magnetic memories, and magnetoelectric devices in general