[Design and clinical application of goal-oriented retroperitoneoscopic adrenalectomy].

Objective: To investigate the goal-oriented retroperitoneoscopic adrenalectomy and report the initial experiment. Methods: A total of 102 patients were selected to our clinic experiment, and performed retroperitoneoscopic adrenalectomy with the new method. including adrenal cortex adenoma 76 cases, phaochromocytoma 12 cases, adrenal cyst 6 cases, myelolipoma 4 cases, gangliocytoma 1 case and corticohyperplassia 3 cases. The mean diameter of the tumors was 2.8 cm (0.5-5.8 cm). The operative procedure was briefly described as such, with ultrasound guiding, a needle was punched percutaneously up to the adrenal mass or the renal upper pole from lateral to posterior axillary line just below the inferior border of the 12th rib. labeled the pathway of the needle with methylene blue. Along the way of the needle, a 12 mm port was introduced into the retroperitoneal space with closed method, and the laparoscope with a working tunnel was introduced to make a tunnel along the label up to the adrenal for finally removing it. Additional port should be used when it was needed in the procedure. Results: The procedures of all patients were successful, and 10 patients were performed with only one port, 81 patients with two ports, 11 patients with three ports. The operative duration was 49 (31-115) min, the average blood loss was 38 (0-260) ml. There was no transition to open surgery and no perioperative complications. The length of postoperative hospital stay was 4.1 d (2-7 d). 98 patients were available for follow-up of 16.5 months (1-38 months), no complication was found. Conclusions: The new method of retroperitoneoscopic adrenalectomy is feasible and safe for renal masses, and compared to the conventional method, it may be less trauma to the abdominal wall and retropertoneal tissue, and it was also better on cosmetics.

HNS, a nuclear-cytoplasmic shuttling sequence in HuR.

Proteins are transported into and out of the cell nucleus via specific signals. The two best-studied nuclear transport processes are mediated either by classical nuclear localization signals or nuclear export signals. There also are shuttling sequences that direct the bidirectional transport of RNA-binding proteins. Two examples are the M9 sequence in heterogeneous nuclear ribonucleoprotein A1 and the heterogeneous nuclear ribonucleoprotein K shuttling domain (KNS) sequence in heterogeneous nuclear ribonucleoprotein K, both of which appear to contribute importantly to the export of mRNA to the cytoplasm. HuR is an RNA-binding protein that can stabilize labile mRNAs containing AU-rich elements in their 3' untranslated regions and has been shown to shuttle between the nucleus and cytoplasm (18, 19). We have identified in HuR a shuttling sequence that also possess transcription-dependent nuclear localization signal activity. We propose that HuR first may bind AU-rich element-containing mRNAs in the nucleus and then escort them through the nuclear pore, providing protection during and after export to the cytoplasmic compartment.

Overexpression of HuR, a nuclear-cytoplasmic shuttling protein, increases the in vivo stability of ARE-containing mRNAs.

The messenger RNAs of many proto-oncogenes, cytokines and lymphokines are targeted for rapid degradation through AU-rich elements (AREs) located in their 3' untranslated regions (UTRs). HuR, a ubiquitously expressed member of the Elav family of RNA binding proteins, exhibits specific affinities for ARE-containing RNA sequences in vitro which correlate with their in vivo decay rates, thereby implicating HuR in the ARE-mediated degradation pathway. We have transiently transfected HuR into mouse L929 cells and observed that overexpression of HuR enhances the stability of beta-globin reporter mRNAs containing either class I or class II AREs. The increase in mRNA stability parallels the level of HuR overexpression, establishing an in vivo role for HuR in mRNA decay. Furthermore, overexpression of HuR deletion mutants lacking RNA recognition motif 3 (RRM 3) does not exert a stabilizing effect, indicating that RRM 3 is important for HuR function. We have also developed polyclonal anti-HuR antibodies. Immunofluorescent staining of HeLa and L929 cells using affinity-purified anti-HuR antibody shows that both endogenous and overexpressed HuR proteins are localized in the nucleus. By forming HeLa-L929 cell heterokaryons, we demonstrate that HuR shuttles between the nucleus and cytoplasm. Thus, HuR may initially bind to ARE-containing mRNAs in the nucleus and provide protection during and after their export to the cytoplasmic compartment.

AU-rich elements target small nuclear RNAs as well as mRNAs for rapid degradation.

AU-rich elements (AREs, usually containing repeated copies of AUUUA), when present in the 3'-untranslated regions (UTRs) of many mammalian mRNAs, confer instability on their host RNA molecules. The viral small nuclear RNA (snRNA) Herpesvirus saimiri U RNA 1 (HSUR 1) also contains an AUUUA-rich sequence. Here, we report that this ARE induces rapid degradation of HSUR 1 itself and of other snRNAs including HSUR 2 and cellular U1. Mutational analyses of the viral ARE establish that sequence requirements for mRNA and snRNA decay are the same, suggesting a similar mechanism. Moreover, the in vivo degradation activity of mutant AREs correlates with their in vitro binding to the HuR protein, implicated previously as a component of the mRNA degradation machinery. Our results suggest that ARE-mediated instability can be uncoupled from both ongoing translation and deadenylation of the target RNA.

Identification of HuR as a protein implicated in AUUUA-mediated mRNA decay.

Expression of many proto-oncogenes, cytokines and lymphokines is regulated by targeting their messenger RNAs for rapid degradation. Essential signals for this control are AU-rich elements (AREs) in the 3' untranslated region (UTR) of these messages. The ARE is loosely defined as the five-nucleotide sequence AUUUA embedded in a uracil-rich region. A transacting factor, presumably a protein, binds the ARE and initiates recognition by the destabilization machinery. Numerous candidate ARE-binding proteins have been proposed. We show that a 32 kDa protein in HeLa nuclear extracts characterized previously has RNA-binding specificity that correlates with the activity of an ARE in directing mRNA decay. Purification and subsequent analyses demonstrate that this 32 kDa protein is identical to a recently identified member of the Elav-like gene family (ELG) called HuR. The in vitro binding selectivity of HuR is indicative of an ARE sequence's ability to destabilize a mRNA in vivo, suggesting a critical role for HuR in the regulation of mRNA degradation.