Laser Lithotripsy — The New Wave

Currently more than 90% of all common bile duct concrements can he removed via the endoscopic retrograde route by means of endoscopic papillotomy, stone extraction by baskets and balloon catheters, or mechanical lithotripsy. Oversized, very hard or impacted stones however often st ill resist conventional endoscopic therapy. Laser lithotripsy represents a promising new endoscopic approach to the nonsurgical treatment of those common bile duct stones. Currently only short-pulsed laser systems with high power peaks but low potential for thermal tissue damage are used for stone fragmentation. Systems in clinical applications are the pulsed free-running-mode neodymium YAG (Nd:YAG) laser (1064 nm, 2 ms) and the dye laser (504 nm, 1 to 1.5 μs). Energy transmission via highly flexible 200 ìm quartz fibres allows an endoscopic retrograde approach to the stone via conventional duodenoscope or mother-baby-scope systems. New systems currently in preclinical and first clinical testing are the Q-switched Nd:YAG laser (1064 nm, 20 ns) and the Alexandrite laser (700 to 815 nm, 30 to 500 ns). By means of extremely short nanosecond pulses (10-9 s) for the induction of local shock waves at the stone surface, possible tissue damage is even more reduced. No complications have been reported so far after applying laser lithotripsy clinically in about 120 patients worldwide. Compared to extracorporeal shock wave treatment, laser lithotripsy can be executed in any endoscopy unit in the scope of the endoscopic pretreatment and does not require general anesthesia, which is often necessary for extracorporeal shock wave lithotripsy

Azúcar y nervios: Explanatory models and treatment experiences of Hispanics with diabetes and depression

This study examined the explanatory models of depression, perceived relationships between diabetes and depression, and depression treatment experiences of low-income, Spanish-speaking, Hispanics with diabetes and depression. A purposive sample (n = 19) was selected from participants enrolled in a randomized controlled trial conducted in Los Angeles, California (United States) testing the effectiveness of a health services quality improvement intervention. Four focus groups followed by 10 in-depth semi-structured qualitative interviews were conducted. Data were analyzed using the methodology of coding, consensus, co-occurrence, and comparison, an analytical strategy rooted in grounded theory. Depression was perceived as a serious condition linked to the accumulation of social stressors. Somatic and anxiety-like symptoms and the cultural idiom of nervios were central themes in low-income Hispanics' explanatory models of depression. The perceived reciprocal relationships between diabetes and depression highlighted the multiple pathways by which these two illnesses impact each other and support the integration of diabetes and depression treatments. Concerns about depression treatments included fears about the addictive and harmful properties of antidepressants, worries about taking too many pills, and the stigma attached to taking psychotropic medications. This study provides important insights about the cultural and social dynamics that shape low-income Hispanics' illness and treatment experiences and support the use of patient-centered approaches to reduce the morbidity and mortality associated with diabetes and depression

Excitonic Photoluminescence in Semiconductor Quantum Wells: Plasma versus Excitons

Time-resolved photoluminescence spectra after nonresonant excitation show a distinct 1s resonance, independent of the existence of bound excitons. A microscopic analysis identifies excitonic and electron-hole plasma contributions. For low temperatures and low densities the excitonic emission is extremely sensitive to even minute optically active exciton populations making it possible to extract a phase diagram for incoherent excitonic populations.Comment: 9 pages, 4 figure

Many-Body Dynamics and Exciton Formation Studied by Time-Resolved Photoluminescence

The dynamics of exciton and electron-hole plasma populations is studied via time-resolved photoluminescence after nonresonant excitation. By comparing the peak emission at the exciton resonance with the emission of the continuum, it is possible to experimentally identify regimes where the emission originates predominantly from exciton and/or plasma populations. The results are supported by a microscopic theory which allows one to extract the fraction of bright excitons as a function of time.Comment: 11 pages, 5 figure

Comparing laparoscopic antireflux surgery with esomeprazole in the management of patients with chronic gastro-oesophageal reflux disease: a 3-year interim analysis of the LOTUS trial

BACKGROUND: With the introduction of laparoscopic antireflux surgery (LARS) for gastro-oesophageal reflux disease (GORD) along with the increasing efficacy of modern medical treatment, a direct comparison is warranted. The 3-year interim results of a randomised study comparing both the efficacy and safety of LARS and esomeprazole (ESO) are reported. METHODS: LOTUS is an open, parallel-group multicentre, randomised and controlled trial conducted in dedicated centres in 11 European countries. LARS was completed according to a standardised protocol, comprising a total fundoplication and a crural repair. Medical treatment comprised ESO 20 mg once daily, which could be increased stepwise to 40 mg once daily and then 20 mg twice daily in the case of incomplete GORD control. The primary outcome variable was time to treatment failure (Kaplan-Meier analysis). Treatment failure was defined on the basis of symptomatic relapse requiring treatment beyond that stated in the protocol. RESULTS: 554 patients were randomised, of whom 288 were allocated to LARS and 266 to ESO. The two study arms were well matched. The proportions of patients who remained in remission after 3 years were similar for the two therapies: 90% of surgical patients compared with 93% medically treated for the intention to treat population, p = 0.25 (90% vs 95% per protocol). No major unexpected postoperative complications were experienced and ESO was well tolerated. However, postfundoplication complaints remain a problem after LARS. CONCLUSIONS: Over the first 3 years of this long-term study, both laparoscopic total fundoplication and continuous ESO treatment were similarly effective and well-tolerated therapeutic strategies for providing effective control of GORD

Efficient 1 GHz Ti:sapphire laser with improved broadband continuum in the infrared

We demonstrate a 1 GHz prismless femtosecond Ti:sapphire ring laser which emits 890 mW for 7.6W of pump power over a continuum extending from 585 to 1200 nm at -20 dB below the maximum. A broadband continuum is obtained without careful mirror dispersion compensation, with the net cavity group-delay-dispersion having -50 to +100 fs2 oscillations from 700 to 900 nm. Further broadening is obtained by use of a slightly convex cavity mirror that increases self-phase modulation. 17% (75%) of the intracavity (output) power is generated in single-pass through the crystal, outside the cavity bandwidth and concentrated in the low gain infrared region from 960 to 1200 nm. This laser seems well suited for optical frequency metrology, possibly allowing easier stabilization of the carrier-to-envelope offset frequency without use of photonic fibers

Efficient Prodrug Activator Gene Therapy by Retroviral Replicating Vectors Prolongs Survival in an Immune-Competent Intracerebral Glioma Model.

Prodrug activator gene therapy mediated by murine leukemia virus (MLV)-based retroviral replicating vectors (RRV) was previously shown to be highly effective in killing glioma cells both in culture and in vivo. To avoid receptor interference and enable dual vector co-infection with MLV-RRV, we have developed another RRV based on gibbon ape leukemia virus (GALV) that also shows robust replicative spread in a wide variety of tumor cells. We evaluated the potential of GALV-based RRV as a cancer therapeutic agent by incorporating yeast cytosine deaminase (CD) and E. coli nitroreductase (NTR) prodrug activator genes into the vector. The expression of CD and NTR genes from GALV-RRV achieved highly efficient delivery of these prodrug activator genes to RG-2 glioma cells, resulting in enhanced cytotoxicity after administering their respective prodrugs 5-fluorocytosine and CB1954 in vitro. In an immune-competent intracerebral RG-2 glioma model, GALV-mediated CD and NTR gene therapy both significantly suppressed tumor growth with CB1954 administration after a single injection of vector supernatant. However, NTR showed greater potency than CD, with control animals receiving GALV-NTR vector alone (i.e., without CB1954 prodrug) showing extensive tumor growth with a median survival time of 17.5 days, while animals receiving GALV-NTR and CB1954 showed significantly prolonged survival with a median survival time of 30 days. In conclusion, GALV-RRV enabled high-efficiency gene transfer and persistent expression of NTR, resulting in efficient cell killing, suppression of tumor growth, and prolonged survival upon CB1954 administration. This validates the use of therapeutic strategies employing this prodrug activator gene to arm GALV-RRV, and opens the door to the possibility of future combination gene therapy with CD-armed MLV-RRV, as the latter vector is currently being evaluated in clinical trials