ABSTRACT
Fever of unknown origin (FUO) poses a diagnostic challenge, and 18-fluorodexoyglucose positron emission tomography with computed tomography (18FDG-PET/CT) may identify the source. We aimed to evaluate the diagnostic yield of 18FDG-PET/CT in the work-up of FUO. The records of patients admitted to Sheba Medical Center between January 2013 and January 2018 who underwent 18FDG-PET/CT for the evaluation of FUO were reviewed. Following examination of available medical test results, 18FDG-PET/CT findings were assessed to determine whether lesions identified proved diagnostic. Of 225 patients who underwent 18FDG-PET/CT for FUO work-up, 128 (57%) met inclusion criteria. Eighty (62.5%) were males; mean age was 59 ± 20.3 (range: 18-93). A final diagnosis was made in 95 (74%) patients. Of the 128 18FDG-PET/CT tests conducted for the workup of FUO, 61 (48%) were true positive, 26 (20%) false positive, 26 (20%) true negative, and 15 (12%) false negative. In a multivariate analysis, weight loss and anemia were independently associated with having a contributary results of 18FDG-PET/CT. The test yielded a sensitivity of 70%, specificity of 37%, positive predictive value of 70%, and negative predictive value of 37%. 18FDG-PET/CT is a valuable tool in the diagnostic workup of FUO. It proved effective in diagnosing almost half the patients, especially in those with anemia and weight loss.
Subject(s)
Fever of Unknown Origin , Fluorodeoxyglucose F18 , Adult , Aged , Fever of Unknown Origin/diagnostic imaging , Fever of Unknown Origin/etiology , Humans , Male , Middle Aged , Positron Emission Tomography Computed Tomography , Positron-Emission Tomography , RadiopharmaceuticalsABSTRACT
Regulation of splicing in eukaryotes occurs through the coordinated action of multiple splicing factors. Exons and introns contain numerous putative binding sites for splicing regulatory proteins. Regulation of splicing is presumably achieved by the combinatorial output of the binding of splicing factors to the corresponding binding sites. Although putative regulatory sites often overlap, no extensive study has examined whether overlapping regulatory sequences provide yet another dimension to splicing regulation. Here we analyzed experimentally-identified splicing regulatory sequences using a computational method based on the natural distribution of nucleotides and splicing regulatory sequences. We uncovered positive and negative interplay between overlapping regulatory sequences. Examination of these overlapping motifs revealed a unique spatial distribution, especially near splice donor sites of exons with weak splice donor sites. The positively selected overlapping splicing regulatory motifs were highly conserved among different species, implying functionality. Overall, these results suggest that overlap of two splicing regulatory binding sites is an evolutionary conserved widespread mechanism of splicing regulation. Finally, over-abundant motif overlaps were experimentally tested in a reporting minigene revealing that overlaps may facilitate a mode of splicing that did not occur in the presence of only one of the two regulatory sequences that comprise it.
Subject(s)
RNA Splicing , Regulatory Sequences, Ribonucleic Acid , Animals , Base Sequence , Binding Sites , Computational Biology/methods , Conserved Sequence , Exons , Humans , RNA Splice Sites , RNA-Binding Proteins/metabolismABSTRACT
Transposable elements (TEs) have contributed a wide range of functional sequences to their host genomes. A recent paper in BMC Molecular Biology discusses the creation of new transcripts by transposable element insertion upstream of retrocopies and the involvement of such insertions in tissue-specific post-transcriptional regulation.
Subject(s)
DNA Transposable Elements/genetics , Genes, Plant/physiology , Genome/physiology , Animals , Base Sequence , Conserved Sequence/genetics , DNA Transposable Elements/ethics , Databases, Genetic , Drosophila melanogaster/genetics , Evolution, Molecular , Gene Deletion , Gene Dosage/genetics , Gene Duplication , Gene Expression Regulation/genetics , Genetic Speciation , Genome, Human/genetics , Humans , Models, Genetic , Mutagenesis, Insertional/methods , PhylogenyABSTRACT
Alternative splicing plays a major role in transcriptome diversity and plasticity, but it is largely unknown how tissue-specific and embryogenesis-specific alternative splicing is regulated. The highly conserved splicing factor Slu7 is involved in 3' splice site selection and also regulates alternative splicing. We show that Slu7 has a unique spatial pattern of expression among human and mouse embryonic and adult tissues. We identified several functional Ets binding sites and GC-boxes in the human Slu7 (hSlu7) promoter region. The Ets and GC-box binding transcription factors, Elk-1 and Sp1, respectively, exerted opposite effects on hSlu7 transcription: Sp1 protein enhances and Elk-1 protein represses transcription in a dose-dependent manner. Sp1 protein bound to the hSlu7 promoter in vivo, and depletion of Sp1 by RNA interference (RNAi) repressed hSlu7 expression. Elk-1 protein bound to the hSlu7 promoter in vivo, and depletion of Elk-1 by RNAi caused an increase in the endogenous level of hSlu7 mRNA. Further, depletion of either Sp1 or Elk-1 affected alternative splicing. Our results provide indications of a complex transcription regulation mechanism that controls the spatial and temporal expression of Slu7, presumably allowing regulation of tissue-specific alternative splicing events.
