Inhibition of Firefly Luciferase by General Anesthetics: Effect on In Vitro and In Vivo Bioluminescence Imaging

<div><h3></h3><p>Bioluminescence imaging is routinely performed in anesthetized mice. Often isoflurane anesthesia is used because of its ease of use and fast induction/recovery. However, general anesthetics have been described as important inhibitors of the luciferase enzyme reaction.</p> <h3>Aim</h3><p>To investigate frequently used mouse anesthetics for their direct effect on the luciferase reaction, both in vitro and in vivo.</p> <h3>Materials and Methods</h3><p>isoflurane, sevoflurane, desflurane, ketamine, xylazine, medetomidine, pentobarbital and avertin were tested in vitro on luciferase-expressing intact cells, and for non-volatile anesthetics on intact cells and cell lysates. In vivo, isoflurane was compared to unanesthetized animals and different anesthetics. Differences in maximal photon emission and time-to-peak photon emission were analyzed.</p> <h3>Results</h3><p>All volatile anesthetics showed a clear inhibitory effect on the luciferase activity of 50% at physiological concentrations. Avertin had a stronger inhibitory effect of 80%. For ketamine and xylazine, increased photon emission was observed in intact cells, but this was not present in cell lysate assays, and was most likely due to cell toxicity and increased cell membrane permeability. In vivo, the highest signal intensities were measured in unanesthetized mice and pentobarbital anesthetized mice, followed by avertin. Isoflurane and ketamine/medetomidine anesthetized mice showed the lowest photon emission (40% of unanesthetized), with significantly longer time-to-peak than unanesthetized, pentobarbital or avertin-anesthetized mice. We conclude that, although strong inhibitory effects of anesthetics are present in vitro, their effect on in vivo BLI quantification is mainly due to their hemodynamic effects on mice and only to a lesser extent due to the direct inhibitory effect.</p> </div

A critical review of vaginal birth rates after a primary Caesarean in Queensland hospitals

Abstract Introduction. For women with a lower uterine incision without indication for repeat Caesarean section (CS), vaginal birth for their next pregnancy is a safe option. Although these women should be encouraged to consider vaginal birth after a Caesarean section (VBAC) it is not consistently supported in practice. There is relatively little information on the extent to which maternal preference, birthing decisions and outcomes match best available evidence. Aim. To describe currentVBACrates for women in Queensland, Australia and compare this to safe, achievableVBAC rates reported in national and international studies. Method. Perinatal data from 2004 to 2011 were reviewed to determine current VBAC rates following a primary CS for women birthing in Queensland. These were compared with VBAC rates reported in the literature. Results. Queensland has a high overall CS rate and high repeat CS rate compared with the national average. In 2010, Queensland VBAC rates for next birth following primary CS were 14% (range 13-21% public sector, 7-11% private hospitals). This is substantially lower than achievable Australian rates of 24% and international rates. Conclusion. Low VBAC rates reflect low numbers of women commencing labour in a pregnancy subsequent to a primary CS. There is unexplained variation inVBACrates between maternity facilities. Clinical reviews to support evidencebased practice are warranted.Full Tex

Evolution of Echocardiographic Measures of Cardiac Disease From CKD to ESRD and Risk of All-Cause Mortality: Findings From the CRIC Study

Rationale &amp; objectiveAbnormal cardiac structure and function are common in chronic kidney disease (CKD) and end-stage renal disease (ESRD) and linked with mortality and heart failure. We examined changes in echocardiographic measures during the transition from CKD to ESRD and their associations with post-ESRD mortality.Study designProspective study.Setting &amp; participantsWe studied 417 participants with CKD in the Chronic Renal Insufficiency Cohort (CRIC) who had research echocardiograms during CKD and ESRD.PredictorWe measured change in left ventricular mass index, left ventricular ejection fraction (LVEF), diastolic relaxation (normal, mildly abnormal, and moderately/severely abnormal), left ventricular end-systolic (LVESV), end-diastolic (LVEDV) volume, and left atrial volume from CKD to ESRD.OutcomesAll-cause mortality after dialysis therapy initiation.Analytical approachCox proportional hazard models were used to test the association of change in each echocardiographic measure with postdialysis mortality.ResultsOver a mean of 2.9 years between pre-&nbsp;and postdialysis echocardiograms, there was worsening of mean LVEF (52.5% to 48.6%; P&lt;0.001) and LVESV (18.6 to 20.2mL/m2.7; P&lt;0.001). During this time, there was improvement in left ventricular mass index (60.4 to 58.4g/m2.7; P=0.005) and diastolic relaxation (11.11% to 4.94% with moderately/severely abnormal; P=0.02). Changes in left atrial volume (4.09 to 4.15mL/m2; P=0.08) or LVEDV (38.6 to 38.4mL/m2.7; P=0.8) were not significant. Worsening from CKD to ESRD of LVEF (adjusted HR for every 1% decline in LVEF, 1.03; 95% CI, 1.00-1.06) and LVESV (adjusted HR for every 1mL/m2.7 increase, 1.04; 95% CI, 1.02-1.07) were independently associated with greater risk for postdialysis mortality.LimitationsSome missing or technically inadequate echocardiograms.ConclusionsIn a longitudinal study of patients with CKD who subsequently initiated dialysis therapy, LVEF and LVESV worsened and were significantly associated with greater risk for postdialysis mortality. There may be opportunities for intervention during this transition period to improve outcomes