Predictive factors for complications in rigid and semirigid retrograde ureteroscopy

Clinica de Urologie şi Transplant Renal, Spital Clinic “Dr. CI Parhon” Iaşi, Al V-lea Congres de Urologie, Dializă şi Transplant Renal din Republica Moldova cu participare internaţională (1-13 iunie 2011)Background. Currently, ureteroscopy is a worldwide procedure with varied number of diagnostic and therapeutic possibilities, including treatment of stones, upper urinary tract tumors, strictures, placement of difficult ureteral stents, and diagnosis of filling defects or haematuria of unknown origin. However, the technique has complications including bleeding, fever and sepsis, ureteral perforation, false passage, urinoma, strictures and, rarely, ureteral avulsion. PURPOSE. Our purpose was to evaluate the ureteroscopies with long hospitalization and to analyse the preoperative predictive factors for the complications. METHODS. We retrospectively reviewed all 342 files of the patients who underwent retrograde ureteroscopy for different reasons between january 2005 and december 2009. Data were abstracted on period of hospitalization, indications for the procedure (urolithiasis – site, number and size, reno-ureteral haematuria, filling defects), bioumoral status, outcome and complications of the method. RESULTS. The mean hospitalization time was 6,53 ± 2,09 days, with a preoperative period of 3,37 ± 1,74 days and a postoperatory time of 2,16 ± 1,08 days. Only 40 patients (11,7%) have exceled this postoperatory period due to a complicated outcome, meanwhile the preoperative time was tidely corelated with the diagnostic imaging methods. The success rate of all therapeutic procedures was 84,74% and the overall and major complication rates was 23,09% and 4,97%. The analysis of preoperative factors showed that preoperative bacteriuria is statistically correlated with postoperatory complications, such as fever and sepsis (p<0.001), and persistent haematuria is linked to stone size and ureteral stent size placed at the end of the procedure (8Ch) without having statistical significance. CONCLUSIONS. Our experience suggests that carefully performed retrograde ureteroscopy is a superb tool for the urologist, either for diagnostic or therapeutic purposes. However, when performing an ureteroscopy, one should always bear in mind the possibility of serious complications, including ureteral avulsion or perforation

New SOS diode pumping circuit based on an all-solid-state spiral generator for high-voltage nanosecond applications

Semiconductor opening switch (SOS) diodes are capable to switch currents with a density of more than 1 kA/cm 2 and withstand nanosecond pulses with an amplitude of up to 1 MV. SOS diodes, however, require a specific pumping circuit that must simultaneously provide forward and reverse pumping currents with a time of ∼ 500 and ∼ 100 ns, respectively. Such a pumping circuit with energies > 1 J typically requires a gas-discharge switch or a low-efficient solid-state solution. This study proposes a novel approach to pumping SOS diodes based on a spiral generator (SG) (also known as a vector inversion generator). Due to its wave characteristics, the SG produces a bipolar current discharge that meets the time duration and current amplitude required to pump an SOS diode. Moreover, the initial pulse from the spiral typically has a relatively low current amplitude compared to the opposite polarity secondary pulse, so the SOS diode can operate at very high efficiencies. This idea has been tested using an all-solid-state SG coupled with large-area SOS diodes (1 cm 2 ). With this combination, a voltage pulse of 62 kV having a rise time of only 11 ns was obtained on an open circuit load (3 pF, 1 M Ω ). The experiments were highly repeatable, with no damage to the components despite multiple tests. There is significant scope to further improve the results, with simple alterations to the SG

MIDOT: A novel probe for monitoring high-current flat transmission lines

This paper was published in the journal Review of Scientific Instruments and the definitive published version is available at http://dx.doi.org/10.1063/1.4971246A novel inductive probe, termed MIDOT, was developed for monitoring high-current flat transmission lines. While being inexpensive the probe does not require calibration, is resistant to both shock waves and temperature variations, and it is easy to manufacture and mount. It generates strong output signals that are relatively easy to interpret and has a detection region limited to a pre-defined part of the transmission line. The theoretical background related to the MIDOT probes, together with their practical implementation in both preliminary experimentation and high-current tests, is also presented in the paper. The novel probe can be used to benchmark existing 2D numerical codes used in calculating the current distribution inside the conductors of a transmission line but can easily detect an early movement of a transmission line component. The probe can also find other applications, such as locating the position of a pulsed current flowing through a thin wire

The distribution of inverted repeat sequences in the Saccharomyces cerevisiae genome

Although a variety of possible functions have been proposed for inverted repeat sequences (IRs), it is not known which of them might occur in vivo. We investigate this question by assessing the distributions and properties of IRs in the Saccharomyces cerevisiae (SC) genome. Using the IRFinder algorithm we detect 100,514 IRs having copy length greater than 6 bp and spacer length less than 77 bp. To assess statistical significance we also determine the IR distributions in two types of randomization of the S. cerevisiae genome. We find that the S. cerevisiae genome is significantly enriched in IRs relative to random. The S. cerevisiae IRs are significantly longer and contain fewer imperfections than those from the randomized genomes, suggesting that processes to lengthen and/or correct errors in IRs may be operative in vivo. The S. cerevisiae IRs are highly clustered in intergenic regions, while their occurrence in coding sequences is consistent with random. Clustering is stronger in the 3′ flanks of genes than in their 5′ flanks. However, the S. cerevisiae genome is not enriched in those IRs that would extrude cruciforms, suggesting that this is not a common event. Various explanations for these results are considered

Altering Chemosensitivity by Modulating Translation Elongation

BACKGROUND: The process of translation occurs at a nexus point downstream of a number of signal pathways and developmental processes. Modeling activation of the PTEN/AKT/mTOR pathway in the Emu-Myc mouse is a valuable tool to study tumor genotype/chemosensitivity relationships in vivo. In this model, blocking translation initiation with silvestrol, an inhibitor of the ribosome recruitment step has been showed to modulate the sensitivity of the tumors to the effect of standard chemotherapy. However, inhibitors of translation elongation have been tested as potential anti-cancer therapeutic agents in vitro, but have not been extensively tested in genetically well-defined mouse tumor models or for potential synergy with standard of care agents. METHODOLOGY/PRINCIPAL FINDINGS: Here, we chose four structurally different chemical inhibitors of translation elongation: homoharringtonine, bruceantin, didemnin B and cycloheximide, and tested their ability to alter the chemoresistance of Emu-myc lymphomas harbouring lesions in Pten, Tsc2, Bcl-2, or eIF4E. We show that in some genetic settings, translation elongation inhibitors are able to synergize with doxorubicin by reinstating an apoptotic program in tumor cells. We attribute this effect to a reduction in levels of pro-oncogenic or pro-survival proteins having short half-lives, like Mcl-1, cyclin D1 or c-Myc. Using lymphomas cells grown ex vivo we reproduced the synergy observed in mice between chemotherapy and elongation inhibition and show that this is reversed by blocking protein degradation with a proteasome inhibitor. CONCLUSION/SIGNIFICANCE: Our results indicate that depleting short-lived pro-survival factors by inhibiting their synthesis could achieve a therapeutic response in tumors harboring PTEN/AKT/mTOR pathway mutations

A Tesla-pulse forming line-plasma opening switch pulsed power generator

This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.A pulsed power generator based on a high-voltage Tesla transformer which charges a 3.85 /55 ns water-filled pulse forming line to 300 kV has been developed at Loughborough University as a training tool for pulsed power students. The generator uses all forms of insulation specific to pulsed power technology, liquid oil and water , gas SF6 , and magnetic insulation in vacuum, and a number of fast voltage and current sensors are implemented for diagnostic purposes. A miniature centimeter-size plasma opening switch has recently been coupled to the output of the pulse forming line, with the overall system comprising the first phase of a program aimed at the development of a novel repetitive, table-top generator capable of producing 15 GW pulses for high power microwave loads. Technical details of all the generator components and the main experimental results obtained during the program and demonstrations of their performance are presented in the paper, together with a description of the various diagnostic tools involved. In particular, it is shown that the miniature plasma opening switch is capable of reducing the rise time of the input current while significantly increasing the load power. Future plans are outlined in the conclusions