Experimental Evolution Reveals Interplay between Sch9 and Polyploid Stability in Yeast.

Polyploidization has crucial impacts on the evolution of different eukaryotic lineages including fungi, plants and animals. Recent genome data suggest that, for many polyploidization events, all duplicated chromosomes are maintained and genome reorganizations occur much later during evolution. However, newly-formed polyploid genomes are intrinsically unstable and often quickly degenerate into aneuploidy or diploidy. The transition between these two states remains enigmatic. In this study, laboratory evolution experiments were conducted to investigate this phenomenon. We show that robust tetraploidy is achieved in evolved yeast cells by increasing the abundance of Sch9-a protein kinase activated by the TORC1 (Target of Rapamycin Complex 1) and other signaling pathways. Overexpressing SCH9, but not TOR1, allows newly-formed tetraploids to exhibit evolved phenotypes and knocking out SCH9 diminishes the evolved phenotypes. Furthermore, when cells were challenged with conditions causing ancestral cells to evolve aneuploidy, tetraploidy was maintained in the evolved lines. Our results reveal a determinant role for Sch9 during the early stage of polyploid evolution.

The V-val subtype Epstein-Barr virus nuclear antigen 1 promotes cell survival after serum withdrawal.

Epstein-Barr virus (EBV) can establish latent infection and has been associated with various human cancers. Epstein-Barr nuclear antigen 1 (EBNA1) is the only viral protein that is expressed in all EBV-associated malignant tissues. The N- and C-terminal domains of EBNA1, which are connected by internal glycine/alanine-rich short repeat sequences of various sizes, show sequence divergence across EBV strains isolated from around the world. At least five subtypes have been described, according to the amino acid at residue 487: P-ala, P-thr, V-val, V-pro, and V-leu. Whether the variations of EBNA-1 contribute to the pathogenesis of EBV or simply reflect the geographical distribution of EBV remain to be investigated. Furthermore, the cell effects conferred by EBNA1 subtypes that differ from that of the B95.8 prototype, which belongs to the P-ala subtype, remain to be elucidated. In this study, PCR was amplified with the full-length V-val EBNA1 gene from the CG3 cell line, an EBV-carrying lymphoblastoid cell line derived from a Taiwanese chronic myeloid leukemia patient. Plasmids expressing His-tagged EBNA1 fusion proteins in E. coli were constructed and used to raise antibodies in rabbit. The V-val EBNA1 gene was then cloned into a eukaryotic expression vector and successfully expressed in the transfected cultured cells. Expression of V-val EBNA1 rendered 293 cells able to undergo serum­independent cell proliferation, providing them with anti-apoptotic abilities, which are two characteristics of cancer cells. These data suggested that use of EBNA1 originally derived from tumor cells, rather than the more commonly utilized prototype, when investigating the potential role of EBNA1 in the oncogenesis of EBV-associated malignancies, is crucial.

Types of Renal Calculi and Management Regimen for Chinese Minimally Invasive Percutaneous Nephrolithotomy.

Strict selection of patients for minimally invasive percutaneous nephrolithotomy could effectively improve the success rate of surgery. This study aimed to understand the required skills and the efficacy of mini-PCNL in the treatment of five types of upper ureteral calculi. Data collected after X-ray analysis and B mode ultrasound from 633 patients with upper ureteral and renal pelvis calculi who underwent B ultrasound-guided lithotomy was reviewed, including the following: type I, upper ureteral or renal pelvis calculi with moderate hydronephrosis (154 cases); type II, upper ureteral or renal pelvis calculi with severe hydronephrosis (157 cases); type III, upper ureteral or renal pelvis calculi without hydronephrosis (61 cases); type IV, renal pelvis calculi, one or two renal calyx calculi (206 cases); and type V, renal staghorn calculi (55 cases). Operations on 611 cases were successful. The treatment method for five patients was converted to open surgery. Twelve cases were treated by indwelling double-J tube retro-catheterization and extracorporeal shock wave lithotripsy. Five patients gave up the treatment. The rate of calculus clearance was 82.3 %, and the rate of residual calculus was 17.6 %. Selective renal artery embolization was performed in nine cases. Hydropneumothorax occurred in nine cases. No intestinal fistula occurred, and no patient had to undergo nephrectomy. The difficulty and the curative effect of the operation were different because the types of calculi varied. Selection of the procedure based on the different types of calculi could effectively improve the success rate of the procedure, reduce complications, and shorten the learning curve.

Erratum to: Types of Renal Calculi and Management Regimen for Chinese Minimally Invasive Percutaneous Nephrolithotomy.

[This corrects the article DOI: 10.1007/s12262-014-1043-4.].

Clinical effectiveness of the PolyScope™ endoscope system combined with holmium laser lithotripsy in the treatment of upper urinary calculi with a diameter of less than 2 cm.

The aim of this study was to evaluate the clinical value of the PolyScope™ endoscope system in the treatment of upper urinary calculi with a diameter of <2 cm. A total of 86 patients hospitalized with upper urinary tract calculi were included. The patients were placed under general or spinal anesthesia and in a lithotomy position. Following the dilation of the ureter, a guide wire was inserted under the direct vision of an F8/9.8 rigid ureteroscope, and an F12/14 flexible ureteral access sheath was positioned along the guide wire. Holmium laser lithotripsy was subsequently performed, using an F8.0 'PolyScope' modular flexible ureteroscope. Plain film of the kidney-ureter-bladder (KUB) was performed 1 day subsequent to the surgery, in order to determine the result of the lithotripsy and the position of the double-J stent which was inserted after after holmium laser lithotripsy. In addition, in certain patients, KUB radiography was performed 2-4 weeks subsequent to the surgery, and extracorporeal shockwave lithotripsy (ESWL) was performed if the diameter of the residual stones was >6 mm. Lithotripsy was successful in 77 patients and the duration of the surgery ranged between 25 and 80 min (mean duration, 42 min). Little bleeding was observed. Three patients presented with a slight fever following the surgery; however, no ureteral perforation, high fever or septicemia was observed among the patients following anti-inflammatory treatment. The stone-free rate (SFR) of the single-pass lithotripsy was 89.5% (77/86) and the SFR with ESWL was 96.5% (83/86). The study demonstrated that the F8 modular flexible ureteroscope was safe, convenient and effective for the lithotripsy of upper-tract calculi.

Minimally invasive percutaneous cystostomy with ureteroscopic pneumatic lithotripsy for calculus in bladder diverticula.

The aim of this study was to investigate the effectiveness of minimally invasive percutaneous cystostomy with ureteroscopic pneumatic lithotripsy for treating calculus in bladder diverticula. Percutaneous cystostomy with ureteroscopic pneumatic lithotripsy was performed on six elderly male patients with calculi in bladder diverticula, who could not be treated with transurethral ureteroscopic lithotripsy. The stones were successfully removed from all patients, with no complications such as bladder perforation, rupture, urethritis or cystitis. The surgery time was 15-60 min, with an average time of 32 min. Postoperative ultrasound or X-ray examination showed no stone residues and the bladder stoma healed well. No recurrent stones were detected in the follow-up of 3-24 months (average, 16 months). Minimally invasive percutaneous cystostomy with ureteroscopic pneumatic lithotripsy is a safe, efficient and easy treatment for calculus in bladder diverticula. This method provides a new clinical approach for lithotripsy and we suggest that it is worthy of wider use.