Extended Sentinel Monitoring of Helicoverpa zea Resistance to Cry and Vip3Aa Toxins in Bt Sweet Corn: Assessing Changes in Phenotypic and Allele Frequencies of Resistance

Transgenic corn and cotton that produce Cry and Vip3Aa toxins derived from Bacillus thuringiensis (Bt) are widely planted in the United States to control lepidopteran pests. The sustainability of these Bt crops is threatened because the corn earworm/bollworm, Helicoverpa zea (Boddie), is evolving a resistance to these toxins. Using Bt sweet corn as a sentinel plant to monitor the evolution of resistance, collaborators established 146 trials in twenty-five states and five Canadian provinces during 2020–2022. The study evaluated overall changes in the phenotypic frequency of resistance (the ratio of larval densities in Bt ears relative to densities in non-Bt ears) in H. zea populations and the range of resistance allele frequencies for Cry1Ab and Vip3Aa. The results revealed a widespread resistance to Cry1Ab, Cry2Ab2, and Cry1A.105 Cry toxins, with higher numbers of larvae surviving in Bt ears than in non-Bt ears at many trial locations. Depending on assumptions about the inheritance of resistance, allele frequencies for Cry1Ab ranged from 0.465 (dominant resistance) to 0.995 (recessive resistance). Although Vip3Aa provided high control efficacy against H. zea, the results show a notable increase in ear damage and a number of surviving older larvae, particularly at southern locations. Assuming recessive resistance, the estimated resistance allele frequencies for Vip3Aa ranged from 0.115 in the Gulf states to 0.032 at more northern locations. These findings indicate that better resistance management practices are urgently needed to sustain efficacy the of corn and cotton that produce Vip3Aa

Inhaled methoxyflurane for pain and anxiety relief during burn wound care procedures: an Australian case series

Pain is a common and significant feature of burn injury. The use of intravenous opioids forms the mainstay of procedural burn pain management, but in an outpatient setting, the demand for novel agents that do not require parenteral access, are easy to administer and have a rapid onset are urgently needed. One such agent is the inhaled anaesthetic agent, methoxyflurane (MF). The aim of this study was to conduct a pilot investigation into the clinical effectiveness of MF inhaler on pain and anxiety scores in patients undergoing burn wound care procedures in an outpatient setting. A prospective case series involved recruiting patients undergoing a burn wound care procedure in an ambulatory burn care setting. Pain and anxiety were assessed using numerical rating scales. Overall, median numerical pain rating score was significantly higher post-dressing [pre-dressing: 2; interquartile range (IQR): 1–3 versus post-dressing: 3; IQR 1·5–4; P = 0·01], whereas median numerical anxiety score significantly reduced following the dressing (pre-dressing: 5; IQR 4–7 versus post-dressing: 2; IQR 1–2; P < 0·001). Our study suggests that there is a role for MF in the pain management armamentarium in those undergoing burn care procedures in the ambulatory care setting. However, there is an urgent need for larger case series and randomised controlled trials to determine its overall clinical effectiveness

Mortality and use of the auxiliary score in extensive toxic epidermal necrolysis patients admitted to an adult burns referral centre

&nbsp;Background: Toxic epidermal necrolysis (TEN) is a rare but fatal condition characterised by cutaneous exfoliation of the dermoepidermal layer and mucosal surfaces. Extensive TEN with epidermal detachment &gt;30% of the total body surface area has been associated with a high mortality. Objective: This study aims to evaluate factors associated with mortality in extensive TEN. In the absence of data to qualify scoring systems such as SCORTEN, this study also aims to evaluate the use of the auxiliary score as a tool for calculating expected mortality. Methods: A retrospective chart review of all patients presenting to our burns service with extensive TEN was undertaken. Application and evaluation of the auxiliary score was also undertaken for this patient population. Results: In extensive TEN, age and delay in admission to a burns centre were factors associated with mortality. Applying the auxiliary score to our patient population, there were no significant differences between expected mortality and observed mortality. Conclusion: Mortality was associated with age and delay in definitive treatment in extensive TEN. Whilst SCORTEN is the gold standard prognostic tool for patients with TEN, in the absence of SCORTEN values, the auxiliary score provides an alternative scoring system to evaluate expected mortality

A systematic review of the management and outcome of toxic epidermal necrolysis treated in burns centres

IntroductionToxic epidermal necrolysis (TEN) is a rare condition characterised by mucocutaneous exfoliation of greater than 30% total body surface area (%TBSA), increasingly being treated in burns centres. The rate of mortality varies significantly in the literature, with recent prospective studies in non-burns centres reporting percentage mortality of approximately 45%. We undertook a systematic review of published studies that included TEN patients treated specifically in burns centres to determine a cumulative mortality rate.MethodsElectronic searches of MEDLINE, EMBASE and The Cochrane Library (Issue 4, 2010) databases from 1966 onwards were used to identify English articles related to the treatment of TEN in burns centres.ResultsThe systematic literature search identified 20 studies which specifically described patients with TEN grater than 30% %TBSA. Treatment regimens varied amongst studies, as did mortality. The overall percentage mortality of the combined populations was 30%. Risk factors commonly described as associated with mortality included age, %TBSA and delay to definitive treatment.ConclusionThe review highlights the variation between principles of treatment and mortality amongst burns centres. It offers a standard that burns centre can use to internationally compare their mortality rates. The review supports the ongoing reporting of outcomes in TEN patients with epidermal detachment greater than 30%

Intravenous lidocaine for the treatment of background or procedural burn pain

Background: This is an update of the review on "Lidocaine for pain relief in burn injured patients" first published in Issue 3, 2007, and first updated in 2012. Pain is a major issue for people with many different types of wounds, in particular those people with burn injuries. Prompt, aggressive use of opioid analgesics such as morphine has been suggested as critical to avert the cycle of pain and anxiety, but adverse effects are encountered. It has been proposed that newer agents such as lidocaine could be effective in reducing pain and alleviating the escalating opioid dosage requirements in people with burn injury. Objectives: To assess the safety and effectiveness of intravenous lidocaine as a means of pain relief versus no therapy, placebo, other drugs, or a combination of these therapies in people with burn injury. Search methods: For this third update, we searched the Cochrane Central Register of Controlled Trials (Issue 11, 2013), and Ovid MEDLINE, MEDLINE in Process and Ovid EMBASE (up to December 2013). Selection criteria: We included randomised controlled trials (RCTs) and controlled clinical trials (CCTs), published and unpublished, which assessed the efficacy of intravenous lidocaine in varying doses as a single-agent therapy with no therapy, placebo, other analgesics (such as opioids), lidocaine plus another drug, or a combination of these therapies as a means of pain relief in people with burn injury. Data collection and analysis: Two review authors independently abstracted data and assessed the risk of bias of the studies identified. Main results: In this 2014 update, we found no new studies. The one small randomised double-blind placebo-controlled cross-over trial found in 2012, which included only 45 participants and compared intravenous lidocaine against placebo as a means of pain relief in people with burns still remains central to this review. We assessed this study as being at a high risk of bias due to its small size (fewer than 50 participants per treatment arm). Subjective pain ratings, as measured by the verbal rating scale, increased during procedures for both treatment arms; however, the increase was less in the lidocaine treatment group. There were no significant clinical or statistical differences regarding the effects of lidocaine and placebo on opioid requests and consumption, anxiety or level of satisfaction during a wound care procedure, but the small included study provided insufficient data to draw any conclusions. Authors' conclusions: As current clinical evidence is based on only one RCT as well as case series and reports, intravenous lidocaine must be considered a pharmacological agent under investigation in burns care, the effectiveness of which is yet to be determined with further well-designed and conducted clinical trials