The loss of HBII-52 and related C/D box small nucleolar RNA (snoRNA) expression units have been implicated as a cause for the Prader-Willi syndrome (PWS). We recently found that the C/D box snoRNA HBII-52 changes the alternative splicing of the serotonin receptor 2C pre-mRNA, which is different from the traditional C/D box snoRNA function in non-mRNA methylation. Using bioinformatic predictions and experimental verification, we identified five pre-mRNAs (DPM2, TAF1, RALGPS1, PBRM1 and CRHR1) containing alternative exons that are regulated by MBII-52, the mouse homolog of HBII-52. Analysis of a single member of the MBII-52 cluster of snoRNAs by RNase protection and northern blot analysis shows that the MBII-52 expressing unit generates shorter RNAs that originate from the full-length MBII-52 snoRNA through additional processing steps. These novel RNAs associate with hnRNPs and not with proteins associated with canonical C/D box snoRNAs. Our data indicate that not a traditional C/D box snoRNA MBII-52, but a processed version lacking the snoRNA stem is the predominant MBII-52 RNA missing in PWS. This processed snoRNA functions in alternative splice-site selection. Its substitution could be a therapeutic principle for PWS.
MicroRNAs in blood samples have been identified as an important class of biomarkers, which can reflect physiological changes from cancer to brain dysfunction. In this report we identify concordant increases in levels of expression of miR-34a in brain and two components of mouse blood samples, peripheral blood mononuclear cells (PBMCs) and plasma, from 2 day old neonates through young adulthood and mid-life to old age at 25 months. Levels of this microRNA's prime target, silent information regulator 1 (SIRT1), in brain and the two blood-derived specimens decrease with age inversely to miR-34a, starting as early as 4 months old, when appreciable tissue aging has not yet begun. Our results suggest that: 1. Increased miR-34a and the reciprocal decrease of its target, SIRT1, in blood specimens are the accessible biomarkers for age-dependent changes in brain; and 2. these changes are predictors of impending decline in brain function, as early as in young adult mice.
Pilonidal disease presents many therapeutic challenges to surgeons throughout the world. Its varied clinical presentations necessitate a wide range of treatments, thus underscoring the need to tailor the treatment to the patient and the severity of disease. Recent studies confirm the efficacy of smaller, more conservative operations for appropriate indications. When flap closures are performed, every attempt should be directed to placing sutures off (lateral) to the midline gluteal cleft. Meticulous attention to the details of immediate and long-term postoperative care is paramount.
The decline in cognitive robustness with aging can be attributed to complex genetic pathways involving many cellular dysfunctions, cumulative over time, precipitating in frailty and loss of wellness in the elderly brain. The size and health of the neuronal cell population determines cognitive robustness in mammals. A transgenic mouse model over-expressing Bcl-2 has been shown to rescue neurons from naturally occurring cell death (NOCD). Here we show that in the brain of calorie-restricted (CR) mice, there is an age-dependent decreased expression of microRNAs mmu-miR-181a-1*, mmu-miR-30e and mmu-miR-34a, with a corresponding gain in Bcl-2 expression, and decreases in pro-apoptosis genes such as Bax and cleavage of Caspases. Functional characterization shows that these miRNAs repress Bcl-2 expression by the 3'UTR reporter assays, accompanied by loss of this gene's endogenous expression, and a gain in pro-apoptosome-specific proteins. Over-expression of these miRNAs increases the rate of apoptosis, accompanied by a decline in Bcl-2 expression in miRNA-transfected mouse and human cell lines. We report here that down-regulation of miR-34a, -30e, and -181a permits their shared target gene expression (Bcl-2) to remain at a high level without post-transcriptional repression, accompanied by concomitant low levels of Bax expression and Caspase cleaving; this chain event may be a part of the underlying mechanism contributing to the gain in neuronal survival in long-lived CR-fed mice.
Performance on the carotid stenting simulator correlated with previous endovascular experience. Although both novice and advanced groups improved their time after a 30-minute to 60-minute proctored training session, improvement in the novice group was greater than that in the advanced group, which suggests that novices may benefit disproportionately from this type of training.
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