One session laparoscopic management of Mirizzi syndrome: feasible and safe in specialist units

BACKGROUND:To evaluate the laparoscopic management of Mirizzi syndrome, seldom diagnosed preoperatively causing difficulty when performing cholecystectomy and increasing complication risks. METHODS:Analysis of a prospective single-surgeon database of 5700 laparoscopic cholecystectomies found 58 Mirizzi syndrome cases. They were managed with an intention to treat during the index admission according to protocol of single-session management of bile duct stones. RESULTS:38/58 patients were females (65.5%). The median age was 55 years. 53 cases were emergency admissions. 34 cases (58.6%) only had ultrasound scanning. Operative difficulty was Grade IV in 34 cases (58.6%) and Grade V in 20 (34.5%) (Nassar Scale). There were 33 Mirizzi Type IA, 7 Type IB, 16 Type II and one each of Type III and Type IV. Bile duct exploration was performed in 94.8% through choledochotomy/ transfistula in 58.6% or transcystic in 36.2%. Four cases required conversion to open. Postoperative morbidity occurred in 29%. Two 30-day mortalities occurred from pneumonia in two elderly patients who were late referrals. CONCLUSION:Although the utilization of the laparoscopic approach in managing bile duct stones is not currently widely practiced it was safer in this series than in reported series of open surgery in Mirizzi Syndrome. The optimal approach to Mirizzi Type II is via cholecystocholedochal fistula to explore the bile duct then drain with T-tube through the fistula. It is unnecessary to perform bilioenteric bypass in majority of cases, reducing the morbidity and mortality

Security in Wireless Sensor Networks - Improving the LEAP Protocol

Wireless sensor networks are becoming significantly vital to many applications, and they were initially used by the military for surveillance purposes. One of the biggest concerns of WSNs is that they are very defenceless to security threats. Due to the fact that these networks are susceptible to hackers; it is possible for one to enter and render a network. For example, such networks may be hacked into in the military, using the system to attack friendly forces. Leap protocol offers many security benefits to WSNs. However, with much research it became apparent that LEAP only employs one base station and always assumes that it is trustworthy. It does not consist of defence against hacked or compromised base stations. In this paper, intensive research was undertaken on LEAP protocols, finding out its security drawbacks and limitations. A solution has been proposed in order to overcome the security issues faced in implementing this protocol whilst employing more than one base station. The performance of the proposed solution has been evaluated and simulated to provide a better network performance

Virtual Wireless and Mobile Communication Laboratory

Creating a virtual laboratory for distance learning courses has become recently so important recently for engineering education. In this paper, we provide a full description for a remote access technique used in a wireless and mobile communication laboratory. Hence, the student will be able to perform experiments online and controlling and watching the devices by accessing a camera already built in the laboratory. Signal generator, spectrum analyzer and field-fox devices are used in the virtual laboratory.https://doi.org/10.5923/j.edu.20120201.0

Multi-institutional expert update on the use of laparoscopic bile duct exploration (LBDE) in the management of choledocholithiasis: lesson learned from 3950 procedures

Background: Recently there has been a growing interest in the laparoscopic management of common bile duct stones with gallbladder in situ (LBDE), which is favoring the expansion of this technique. Our study identified the standardization factors of LBDE and its implementation in the single-stage man agement of choledocholithiasis. Methods: A retrospective multi-institutional study among 17 centers with proven experience in LBDE was performed. A cross-sectional survey consisting of a semi-structured pretested questionnaire was distributed covering the main aspects on the use of LBDE in the management of choledocholithiasis. Results: A total of 3950 LBDEs were analyzed. The most frequent indication was jaundice (58.8%). LBDEs were performed after failed ERCP in 15.2%. The most common approach used was the transcystic (63.11%). The overall series failure rate of LBDE was 4% and the median rate for each center was 6% (IQR, 4.5-12.5). Median operative time ranged between 60-120 min (70.6%). Overall morbidity rate was 14.6%, with a postoperative bile leak and complications ≥3a rate of 4.5% and 2.5%, respectively. The operative time decreased with experience (P = .03) and length of hospital stay was longer in the presence of a biliary leak (P = .04). Current training of LBDE was defined as poor or very poor by 82.4%. Conclusion: Based on this multicenter survey, LBDE is a safe and effective ap proach when performed by experienced teams. The generalization of LBDE will be based on developing training programs

Hartmann's Pouch Stones and Laparoscopic Cholecystectomy: the challenges and the solutions

Background & Objective: Hartmann's pouch stones (HPS) encountered during laparoscopic cholecystectomy (LC) may hinder safe dissection of the cystic pedicle or be complicated by mucocele, empyema, or Mirizzi syndrome; distorting the anatomy and increasing the risk of bile duct injury. We studied the incidence, presentations, operative challenges, and outcomes of HPS. Methods: A cohort study of a prospectively maintained database of LCs and bile duct explorations performed by a single surgeon. Patients were divided into two groups: those with HPS and those without. Patients' demographics, clinical presentation, intra-operative findings, and postoperative outcomes were compared. Results: Of the 5136 patients, 612 (11.9%) had HPS. The HPS group were more likely to present with acute cholecystitis (27.9% vs 5.9%, P = .000) and more patients underwent emergency LC (50.7% vs 41.5%, P = .000). The HPS group had more difficult cholecystectomies, with 46.1% vs 11.8% in the non-HPS group being operative difficulty grade 4 and 5. Mucocele, empyema, and Mirizzi syndrome were more common in the HPS group (24.0% vs 3.7% P = .000, 30.9% vs 3.7% P = .000, 1.8% vs 0.9% P = .000, respectively). There was no significant difference in the open conversion rate or complications. Conclusion: HPS increase the difficulty of LC. Surgeons should be aware of their presence and should employ appropriate dissection strategies. Sharp or diathermy dissection should be avoided. Dislodging the stone into the gall bladder, stone removal, swab dissection, and cholangiography are useful measures to avoid ductal injury and reduce the conversion rate

Genotypes and serotype distribution of macrolide resistant invasive and non- invasive Streptococcus pneumoniae isolates from Lebanon

<p>Abstract</p> <p>Background</p> <p>This study determined macrolide resistance genotypes in clinical isolates of <it>Streptococcus pneumoniae </it>from multiple medical centers in Lebanon and assessed the serotype distribution in relation to these mechanism(s) of resistance and the source of isolate recovery.</p> <p>Methods</p> <p>Forty four macrolide resistant and 21 macrolide susceptible <it>S. pneumoniae </it>clinical isolates were tested for antimicrobial susceptibility according to CLSI guidelines (2008) and underwent molecular characterization. Serotyping of these isolates was performed by Multiplex PCR-based serotype deduction using CDC protocols. PCR amplification of macrolide resistant <it>erm </it>(encoding methylase) and <it>mef </it>(encoding macrolide efflux pump protein) genes was carried out.</p> <p>Results</p> <p>Among 44 isolates resistant to erythromycin, 35 were resistant to penicillin and 18 to ceftriaxone. Examination of 44 macrolide resistant isolates by PCR showed that 16 isolates harbored the <it>erm</it>(B) gene, 8 isolates harbored the <it>mef </it>gene, and 14 isolates harbored both the <it>erm</it>(B) and <it>mef </it>genes. There was no amplification by PCR of the <it>erm</it>(B) or <it>mef </it>genes in 6 isolates. Seven different capsular serotypes 2, 9V/9A,12F, 14,19A, 19F, and 23, were detected by multiplex PCR serotype deduction in 35 of 44 macrolide resistant isolates, with 19F being the most prevalent serotype. With the exception of serotype 2, all serotypes were invasive. Isolates belonging to the invasive serotypes 14 and 19F harbored both <it>erm</it>(B) and <it>mef </it>genes. Nine of the 44 macrolide resistant isolates were non-serotypable by our protocols.</p> <p>Conclusion</p> <p>Macrolide resistance in <it>S. pneumoniae </it>in Lebanon is mainly through target site modification but is also mediated through efflux pumps, with serotype 19F having dual resistance and being the most prevalent and invasive.</p

The 40Ca(alpha,gamma)44Ti reaction in the energy regime of supernova nucleosynthesis

The 44Ti(t1/2 = 59 y) nuclide, an important signature of supernova nucleosynthesis, has recently been observed as live radioactivity by gamma-ray astronomy from the Cas A remnant. We investigate in the laboratory the major 44Ti production reaction, 40Ca(alpha,gamma)44Ti (E_cm = 0.6-1.2 MeV/u), by direct off- line counting of 44Ti nuclei. The yield, significantly higher than inferred from previous experiments, is analyzed in terms of a statistical model using microscopic nuclear inputs. The associated stellar rate has important astrophysical consequences, increasing the calculated supernova 44Ti yield by a factor ~2 over previous estimates and bringing it closer to Cas A observations.Comment: To be published in Phys. Rev. lett., 4 pages, 1 table, 2 figure

Massive stars as thermonuclear reactors and their explosions following core collapse

Nuclear reactions transform atomic nuclei inside stars. This is the process of stellar nucleosynthesis. The basic concepts of determining nuclear reaction rates inside stars are reviewed. How stars manage to burn their fuel so slowly most of the time are also considered. Stellar thermonuclear reactions involving protons in hydrostatic burning are discussed first. Then I discuss triple alpha reactions in the helium burning stage. Carbon and oxygen survive in red giant stars because of the nuclear structure of oxygen and neon. Further nuclear burning of carbon, neon, oxygen and silicon in quiescent conditions are discussed next. In the subsequent core-collapse phase, neutronization due to electron capture from the top of the Fermi sea in a degenerate core takes place. The expected signal of neutrinos from a nearby supernova is calculated. The supernova often explodes inside a dense circumstellar medium, which is established due to the progenitor star losing its outermost envelope in a stellar wind or mass transfer in a binary system. The nature of the circumstellar medium and the ejecta of the supernova and their dynamics are revealed by observations in the optical, IR, radio, and X-ray bands, and I discuss some of these observations and their interpretations.Comment: To be published in " Principles and Perspectives in Cosmochemistry" Lecture Notes on Kodai School on Synthesis of Elements in Stars; ed. by Aruna Goswami & Eswar Reddy, Springer Verlag, 2009. Contains 21 figure

Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty