Genetic mapping of putative Chrna7 and Luzp2 neuronal transcriptional enhancers due to impact of a transgene-insertion and 6.8 Mb deletion in a mouse model of Prader-Willi and Angelman syndromes

BACKGROUND: Prader-Willi and Angelman syndrome (PWS and AS) patients typically have an ~5 Mb deletion of human chromosome 15q11-q13, of opposite parental origin. A mouse model of PWS and AS has a transgenic insertion-deletion (TgPWS/TgAS) of chromosome 7B/C subsequent to paternal or maternal inheritance, respectively. In this study, we define the deletion endpoints and examine the impact on expression of flanking genes. RESULTS: Using molecular and cytological methods we demonstrate that 13 imprinted and 11 non-imprinted genes are included in the TgPWS/TgAS deletion. Normal expression levels were found in TgPWS brain for genes extending 9.1- or 5.6-Mb centromeric or telomeric of the deletion, respectively. Our molecular cytological studies map the proximal deletion breakpoint between the Luzp2 and Siglec-H loci, and we show that overall mRNA levels of Luzp2 in TgPWS and TgAS brain are significantly reduced by 17%. Intriguingly, 5' Chrna7 shows 1.7-fold decreased levels in TgPWS and TgAS brain whereas there is a ≥15-fold increase in expression in neonatal liver and spleen of these mouse models. By isolating a Chrna7-Tg fusion transcript from TgAS mice, we mapped the telomeric deletion breakpoint in Chrna7 intron 4. CONCLUSION: Based on the extent of the deletion, TgPWS/TgAS mice are models for PWS/AS class I deletions. Other than for the first gene promoters immediately outside the deletion, since genes extending 5.6–9.1 Mb away from each end of the deletion show normal expression levels in TgPWS brain, this indicates that the transgene array does not induce silencing and there are no additional linked rearrangements. Using gene expression, non-coding conserved sequence (NCCS) and synteny data, we have genetically mapped a putative Luzp2 neuronal enhancer responsible for ~33% of allelic transcriptional activity. The Chrna7 results are explained by hypothesizing loss of an essential neuronal transcriptional enhancer required for ~80% of allelic Chrna7 promoter activity, while the Chrna7 promoter is upregulated in B lymphocytes by the transgene immunoglobulin enhancer. The mapping of a putative Chrna7 neuronal enhancer inside the deletion has significant implications for understanding the transcriptional regulation of this schizophrenia-susceptibility candidate gene

Validity evidence and reliability of a simulated patient feedback instrument

Contains fulltext : 110154.pdf (publisher's version ) (Open Access)BACKGROUND: In the training of healthcare professionals, one of the advantages of communication training with simulated patients (SPs) is the SP's ability to provide direct feedback to students after a simulated clinical encounter. The quality of SP feedback must be monitored, especially because it is well known that feedback can have a profound effect on student performance. Due to the current lack of valid and reliable instruments to assess the quality of SP feedback, our study examined the validity and reliability of one potential instrument, the 'modified Quality of Simulated Patient Feedback Form' (mQSF). METHODS: Content validity of the mQSF was assessed by inviting experts in the area of simulated clinical encounters to rate the importance of the mQSF items. Moreover, generalizability theory was used to examine the reliability of the mQSF. Our data came from videotapes of clinical encounters between six simulated patients and six students and the ensuing feedback from the SPs to the students. Ten faculty members judged the SP feedback according to the items on the mQSF. Three weeks later, this procedure was repeated with the same faculty members and recordings. RESULTS: All but two items of the mQSF received importance ratings of > 2.5 on a four-point rating scale. A generalizability coefficient of 0.77 was established with two judges observing one encounter. CONCLUSIONS: The findings for content validity and reliability with two judges suggest that the mQSF is a valid and reliable instrument to assess the quality of feedback provided by simulated patients

Hydrogen Peroxide in the Troposphere

Uloga vodikova peroksida (H2O2) u atmosferskoj kemiji i njegov doprinos u nastanku slobodnih radikala počeli su se proučavati tek posljednjih nekoliko desetljeća. Fotokemijskim reakcijama s ozonom i H2O2 nastaju oksidansi (slobodni radikali) koji mogu oksidirati biomolekule unutar stanica te dovesti do smrti stanica i ozljeda tkiva. Zbog toga se slobodni radikali smatraju uzrokom više od sto bolesti. H2O2 smatra se boljim indikatorom za atmosferski oksidacijski kapacitet od ozona. U atmosferi može biti prisutan u plinovitoj i tekućoj fazi te pokazuje tipične dnevne i sezonske varijacije. Me|utim, zbog skupe i slo`ene opreme, mjerenja H2O2 su rijetka i ograničena na samo nekoliko mjesta u svijetu. Mjerenja u slojevima leda na Grenlandu pokazala su da koncentracije H2O2 rastu posljednjih 200 godina. Značajan porast primijećen je upravo posljednjih dvaju desetljeća, a procjene pokazuju da će i dalje rasti zbog smanjene emisije sumporova dioksida. Mjerenja H2O2 u Hrvatskoj do sada još nisu bila provedena te će uporedo s već postojećim dugogodišnjim rezultatima mjerenja ozona i dušikovih oksida dati uvid u stanje i utjecaj na oksidativni stres.The past few decades saw a rising interest in the role of hydrogen peroxide (H2O2) in atmospheric chemistry and its contribution to the formation of free radicals. Free radicals (oxidants) are formed by photochemical reactions between ozone and H2O2. Free radicals formed within cells can oxidise biomolecules, and this may lead to cell death and tissue injury. For this reason, free radicals are believed to cause more than 100 diseases. H2O2 has been suggested as a better indicator of atmospheric oxidation capacity than ozone. Atmospheric H2O2 can appear in the gas phase or in the aqueous phase. It shows typical diurnal and seasonal variations. However, measurements of H2O2 with expensive and sophisticated equipment are rare and limited to but a few sites in the world. Measurements in Greenland ice cores showed that H2O2 concentrations increased over the last 200 years and most of the increase has occurred over the last 20 years. Evaluations show that concentrations will still rise as a result of decreasing SO2 emission. H2O2 measurements have not been carried out in Croatia until now, and, accompanied by the existing longterm measurements of ozone and nitrogen oxides, they will provide an idea of the oxidative capacity of the atmosphere and its influence on oxidative stress