ABSTRACT
Turn-over of messenger ribonucleic acid ( mRNA) is a major control point in gene expres-sion.In mammals,many mRNAs encode inflammatory cytokines ,oncoproteins,and G-protein-coupled receptors are destabilized by the presence of AU -rich elements ( AREs ) in their 3′-untranslated regions .Association of ARE-binding proteins(AUBPs)with these mRNAs promotes rapid mRNA degradation .ARE/poly(U)-binding factor 1(AUF1),one of the best-characterized AUBPs,binds to many ARE-mRNAs and assembles other fac-tors to recruit the mRNA degradation machinery .Most studies support an mRNA -destabilizing role for AUF1,al-though other findings suggest additional functions for this factor .However,several lines of evidence also support a role for AUF1 in the initiation and/or development of cancer .Many AUF1-targeted transcripts encode products that control pro-or anti-oncogenic processes .Numerous signaling pathways alter the composition of this AUF 1 complex of proteins to affect changes in ARE -mRNA degradation rates .This review briefly describes the roles of mRNA decay in gene expression in general and ARE -mediated decay ( AMD) in particular ,with a focus on AUF1 and the different modes of regulation that govern AUF 1 involvement in AMD.In the end,we discuss how changes in AUF1 isoform distribution,subcellular localization,and post-translational protein modifications can influence the metabolism of targeted mRNAs .
ABSTRACT
Objective: To explore the effect of single-nostril transsphenoidal approach on pituitary adenoma. Methods: We retrospectively analyzed 46 cases of pituitary tumors treated with single-nostril transsphenoidal approach and the effects and complications of surgery.Dunng the surgery,a nasal speculum was inserted through right nostril slowly towards the anterior wall of sphenoid sinus.A nasal mucosa incision of about 1.5cm was made in the right nasal cavity at the level of the middle nasal turbinate.With a fracture of the bony septum,a space was developed between the bilateral nasal mucosa and bony septum to the sphenoid sinus.Then,the face of the sphenoid sinus was exposed.The remainder of the bony septum,the anterior sphenoid sinus wall,and the sphenoid mucosa were removed.The antenor sphenoidotomy should be less than 1.5cm wide.After confirming the tumor by dural puncture,a cross incision of dura was made and the tumor was removed.The saddle was usually Collapsed and visible after total tumor removal.When the tumor was resected,sevaral gelatin sponges were stuffed into the Surgical cavity to stop bleeding. Results: Thirty-four cases had total resection and 12 cases had subtotal resection.No deaths or disability occurred.Hormone levels in almost all patients were improved.Seventeen cases had a sign of diabetes insipidus.Electrolyte disturbance occuwed in 5 cases.NO postoperative cerebrospinal fluid rhinorrhea was observed. Conclusion: Single-nostril transsphenoidal approach has many advantages in treating pituitary adenomas such as simplified approach,brief technology and high security.