Pancreas: An Organ-at-Risk to Consider in Future Pediatric Abdominal Radiotherapy

PURPOSE/OBJECTIVE(S)

Irradiation to the pancreas during pediatric radiotherapy is associated with secondary late effects, yet the pancreas is not typically considered an organ-at-risk (OAR) during radiotherapy planning. This audit investigated incidental pancreatic doses to estimate the relative risk (RR) of developing diabetes in later life.

MATERIALS/METHODS

Incidental pancreas doses were audited from 92 patients aged 2 to 19 historically treated with photons for craniospinal irradiation (CSI, N = 73) and for abdominal neuroblastoma (N = 19). Prescription doses ranged 21-36 Gy and 21-39 Gy (with boost to spine up to 50 Gy) for neuroblastoma and CSI patients, respectively. The pancreas was segmented on all planning CT scans following RTOG guidelines. Furthermore, the pancreas was split into its sub-volumes (head, body and tail) for abdominal cases only, since these scans were acquired with contrast enhancement. The RR of developing subsequent diabetes was estimated as a function of dose (D): RR = 1+0.65 × D × exp(-0.3 × D). Dose to the pancreas tail was used for neuroblastoma cases, whereas dose to the whole pancreas was used for CSI patients given that the pancreas could not be split in non-contrast scans.

RESULTS

The mean dose delivered to the whole pancreas was 15.4±7.5 Gy for all patients, 12.7±4.7 Gy for CSI patients and 25.9±7.4 Gy for abdominal patients. Pancreas V10Gy was 61.2% for all patients, 51.5% for CSI, and 98.6% for abdominal patients; V30Gy = 0% in all cases. These doses represented an estimated diabetes RR of 7.3±1.5, 6.6±1.3, and 8.7±0.6, respectively; RR>5 in 88%, 85% and 100% of all patients, CSI and abdominal patients audited, respectively.

CONCLUSION

Current incidental doses were associated with a diabetes RR>5 in all patients treated for abdominal neuroblastoma and the majority who received CSI. These findings suggest the pancreas should be routinely delineated and considered as an OAR in radiotherapy planning. This may help to identify higher risk patients and inform late-effect monitoring during survivorship. Further work in underway to assess if proton therapy could reduce the RR of diabetes particularly in abdominal cases. Improved availability of high-quality imaging during radiotherapy planning, such as contrast administration or planning MRI, is becoming more necessary to accurately delineate subsegments of the pancreas for improved RR estimations.

Evaluation of Radiotherapy Dose and Survival Outcomes for Teenagers, and Young Adults with Nasopharyngeal Carcinoma in UK and Ireland

PURPOSE/OBJECTIVE(S)

Nasopharyngeal carcinoma (NPC) follows a bimodal distribution with a smaller incidence peak in teenagers and young adults (TYAs). In TYAs, an over-whelming proportion are associated with Epstein-Barr virus (EBV). We have evaluated the variation in TYA NPC practice patterns across the UK and Ireland, along with survival outcomes.

MATERIALS/METHODS

We performed a multicenter, observational cohort study, of patients aged 13-25 years, with histologically confirmed NPC, treated between the years 2002-2022. An initial expression of interest was sent to selected centers treating H&N patients in the UK and Ireland. For analysis, patients were assessed based on total prescribed dose, with a cut off for low dose (LD) (≤61.2Gy) versus a high dose (HD)(>61.2Gy).

RESULTS

Ninety-five patients, from 9 centers, were eligible for inclusion. Patient demographics are shown in table1. At a median follow up of 45 months (IQR 23-111), 3-year overall survival (OS) was 98% (95% CI 93%-100%) with LD versus 91% (95% CI 83%-99%) with HD (Hazard ratio (HR) = 3.0; 95% CI 0.3-27, p = 0.3). 3-year progression free survival (PFS) was 84% (95% CI 71%-97%) with LD versus 83% (95% CI 72%-94%) with HD (HR 1.3; 95% CI 0.4-4.0, p = 0.6), and 5-year PFS was 84% (95% CI 71%-97%) with LD versus 83% (95% CI 72%-94%) with HD (HR 1.3; 95% CI 0.4-4.0, p = 0.6). Incidence of distant metastasis (DM) was 9.9%. 2 patients (6%) with T3-T4 tumors, treated with LD, had locoregional failure (LRF) compared to 1 patient (3%) treated with HD.

CONCLUSION

We have demonstrated excellent survival outcomes for the UK & Ireland TYA NPC patients. As the majority of cases in this age group have EBV+ NPC, with survival similar between LD and HD protocols, we propose that pediatric protocols, with lower radiotherapy doses should be considered for all TYA NPC, with the aim of reducing late effects. Additional analysis to better understand the impact of heterogeneity between both groups, including choice of protocol, induction and adjuvant treatment will follow this study. Prospective evaluation, as part of an international collaboration, is required to optimize the management strategy for this rare cohort of patients.

Development of Population-Based Pediatric Computational Phantoms for Radiotherapy Applications

PURPOSE/OBJECTIVE(S)

Age-specific pediatric computational phantoms are used in radiotherapy (RT) for quality assurance and for reconstruction of historical RT doses (within others). Phantoms are typically developed from healthy patients and may not effectively represent those with cancer due to pathology and/or treatment effects. This study evaluated a set of population-based pediatric computational phantoms developed in-house in terms of anatomical plausibility.

MATERIALS/METHODS

Planning CTs and contours from historical craniospinal irradiation (CSI) patients (n = 74, median age 7y, range: 1-17y) were used to generate and evaluate a set of in-house age-specific population-based RT phantoms (RT-P). The RT-P were generated by combining a sub-set of clinical CTs and contours through groupwise deformable image registration, generating average models of CSI sub-populations (n = 74, median age 7y, range: 3-14y). Models were then compared against clinical data and two libraries of phantoms representing healthy populations: the International Commission on Radiological Protection (ICRP) pediatric reference computational phantoms (n = 8, median age 8y, range: 1-15y) and a variety of default 4D extended cardiac torso (XCAT) phantoms (n = 75, median age 9y, range: 1-18y). Variation between organ volumes for the different datasets was assessed through a linear fit of organ volume with age, reporting the slope (∑) of each fit [y-1]. Average difference between the volume datapoints and the linear fit for clinical data (Δ) [%] were also reported. This allowed for comparisons of the RT-P to clinical and reference data in terms of organ volumes across developmental stages.

RESULTS

The table shows 9 of the 19 investigated organs. The ∑ reported for RT-P models were of similar magnitude as the clinical data and other phantoms, effectively modelling changes with age. The greatest and least ∑ were reported from lungs and thyroid respectively, in agreement with expected relative sizes between organs. Larger values for Δ were likely due to differences in organ filling and segmentation strategy between datasets, limitations of RT-P methodology, and/or anatomical differences between healthy and cancer populations.

CONCLUSION

The RT-P models show promise in representing the RT cohort that may benefit from specialized anatomical phantoms. Further work is needed to address the limitations of the current methodology and its applicability to other RT cohorts.

A National Referral Service for Paediatric Brachytherapy: An Evolving Practice and Outcomes Over 13 Years

AIMS

Most children requiring radiotherapy receive external beam treatment and few have tumours suitable for brachytherapy. No paediatric radiotherapy centre will treat enough patients from its own normal catchment population for expertise in brachytherapy to be developed and sustained. Following discussion and agreement in the national paediatric radiotherapy group, a service for paediatric brachytherapy in the UK has been developed. We report the process that has evolved over more than 10 years, with survival and functional outcome results.

MATERIALS AND METHODS

Since 2009, potential patients have been referred to the central paediatric oncology multidisciplinary team meeting, where imaging, pathology and treatment options are discussed. Since 2013, the National Soft Tissue Sarcoma Advisory Panel has also reviewed most patients, with the principal aim of advising on the most suitable primary tumour management for complex patients. Clinical assessment and examination under anaesthetic with biopsies may be undertaken to confirm the appropriateness of brachytherapy, either alone or following conservative surgery. Fractionated high dose rate brachytherapy was delivered to a computed tomography planned volume after implantation of catheters under ultrasound imaging guidance. Since 2019, follow-up has been in a dedicated multidisciplinary clinic.

RESULTS

From 2009 to 2021 inclusive, 35 patients (16 female, 19 male, aged 8 months to 17 years 6 months) have been treated. Histology was soft-tissue sarcoma in 33 patients and carcinoma in two. The treated site was pelvic in 31 patients and head and neck in four. With a median follow-up of 5 years, the local control and overall survival rates are 100%. Complications have been few, and functional outcome is good.

CONCLUSION

Brachytherapy is effective for selected paediatric patients, resulting in excellent tumour control and good functional results. It is feasible to deliver paediatric brachytherapy at a single centre within a national referral service.

Pf7: an open dataset of Plasmodium falciparum genome variation in 20,000 worldwide samples

We describe the MalariaGEN Pf7 data resource, the seventh release of Plasmodium falciparum genome variation data from the MalariaGEN network.  It comprises over 20,000 samples from 82 partner studies in 33 countries, including several malaria endemic regions that were previously underrepresented.  For the first time we include dried blood spot samples that were sequenced after selective whole genome amplification, necessitating new methods to genotype copy number variations.  We identify a large number of newly emerging crt mutations in parts of Southeast Asia, and show examples of heterogeneities in patterns of drug resistance within Africa and within the Indian subcontinent.  We describe the profile of variations in the C-terminal of the csp gene and relate this to the sequence used in the RTS,S and R21 malaria vaccines.  Pf7 provides high-quality data on genotype calls for 6 million SNPs and short indels, analysis of large deletions that cause failure of rapid diagnostic tests, and systematic characterisation of six major drug resistance loci, all of which can be freely downloaded from the MalariaGEN website.

P-066 ABDOMINAL WALL RECONSTRUCTION FOLLOWING FULL THICKNESS BILATERAL RUPTURE OF THE RECTUS ABDOMINIS

Introduction

Rupture of the rectus abdominis is rare injury with no consensus on management. Previous reported cases have been due to exercise-related injuries and blunt abdominal trauma. We report the case of a 20-year-old male trainee paratrooper who presented with severe lower abdominal pain that occurred during military training. MRI revealed full-thickness bilateral rupture of the rectus abdominis. Abdominal wall reconstruction involved bilateral rectus muscle repair and placement of a biosynthetic mesh in the retrorectus plane. Postoperatively, our patient could walk pain-free at 3 weeks, jog pain-free at 10 weeks, and run up to 2 miles at 25 weeks.

Methods

Pubmed, Medline and Embase were searched to identify relevant studies using the MeSH terms, “rectus abdominis” and “rupture”, as well as their free text counterparts and synonyms. Texts were restricted to publications in English and publications after the year 2000. The search resulted in 391 articles. Manual cross-referencing was performed, limiting the included articles to 8 for review.

Results

6 out of the 8 selected articles discussed management using conservative means, while only 2 cases were managed surgically. Interestingly, no other exercise-related cases in the literature were managed surgically. Instead, all exercise related cases were managed conservatively, while only cases of traumatic aetiology were managed surgically. Among both surgically and conservatively treated patients, none suffered any treatment related complications, and all patients returned to normal levels of activity.

Conclusion

Full-thickness, bilateral rupture of the rectus abdominis can occur during exercise. Surgical and conservative treatment yield similar results.

602 Using Plastic Surgery Techniques in Abdominal Wall Surgery

Complex Abdominal Wall Hernias (CAWH) present a huge challenge to surgeons and patients often requiring Abdominal Wall Reconstruction (AWR). AWR aims to restore abdominal wall anatomy, improve function, and reduce the risk of future herniation. Plastic surgery techniques can be used including primary closure, skin grafts, flaps, tissue expansion and small bite, small stitch technique. Below are two cases where some of these techniques were utilised.

Case 1

LC is a 65 y/o female with CAWH. Her gastric band became infected requiring a laparotomy for perforation of gastroesophageal junction. She subsequently had primary open repair of abdominal hernia using Permacol. It became infected requiring 5 debridements and application of a VAC device. Her hernia was a Ventral Hernia Working Group (VHWG) grade 3 at 10cm×16cm. Her CAWH was repaired using a Rives-Stoppa technique and a Surgimend mesh. The epigastric component of her wound was closed using a superiorly based local rhomboid flap and a Prevena VAC dressing.

Case 2

KH is a 37 y/o female with a para-ileal conduit skin granuloma that was painful and refractory to other treatments such as silver nitrate and steroid topical treatments. She had excision of the area of granulation and her wound was closed using a local advancement flap taking account of previous scars raised and a prevena VAC dressing.

Discussion

CAWH requiring AWR is a complex operation benefiting from plastic surgical specialists. Plastic surgical techniques can help with closure of the abdominal wall and reduce complication rates including wound infections and incisional hernia.

Comparison of antibody responses and parasite clearance in artemisinin therapeutic efficacy studies in Democratic Republic of Congo and Asia

Background

Understanding the effect of immunity on Plasmodium falciparum clearance is essential for interpreting therapeutic efficacy studies designed to monitor emergence of artemisinin drug resistance. In low-transmission areas of Southeast Asia, where resistance has emerged, P. falciparum antibodies confound parasite clearance measures. However, variation in naturally acquired antibodies across Asian and sub-Saharan African epidemiological contexts and their impact on parasite clearance re yet to be quantified.

Methods

In an artemisinin therapeutic efficacy study, antibodies to 12 pre-erythrocytic and erythrocytic P. falciparum antigens were measured in 118 children with uncomplicated P. falciparum malaria in the Democratic Republic of Congo (DRC) and compared with responses in patients from Asian sites, described elsewhere.

Results

Parasite clearance half-life was shorter in DRC patients (median, 2 hours) compared with most Asian sites (median, 2–7 hours), but P. falciparum antibody levels and seroprevalences were similar. There was no evidence for an association between antibody seropositivity and parasite clearance half-life (mean difference between seronegative and seropositive, −0.14 to +0.40 hour) in DRC patients.

Conclusions

In DRC, where artemisinin remains highly effective, the substantially shorter parasite clearance time compared with Asia was not explained by differences in the P. falciparum antibody responses studied.

An open dataset of Plasmodium vivax genome variation in 1,895 worldwide samples

This report describes the MalariaGEN Pv4 dataset, a new release of curated genome variation data on 1,895 samples of Plasmodium vivax collected at 88 worldwide locations between 2001 and 2017. It includes 1,370 new samples contributed by MalariaGEN and VivaxGEN partner studies in addition to previously published samples from these and other sources. We provide genotype calls at over 4.5 million variable positions including over 3 million single nucleotide polymorphisms (SNPs), as well as short indels and tandem duplications. This enlarged dataset highlights major compartments of parasite population structure, with clear differentiation between Africa, Latin America, Oceania, Western Asia and different parts of Southeast Asia. Each sample has been classified for drug resistance to sulfadoxine, pyrimethamine and mefloquine based on known markers at the dhfr, dhps and mdr1 loci. The prevalence of all of these resistance markers was much higher in Southeast Asia and Oceania than elsewhere. This open resource of analysis-ready genome variation data from the MalariaGEN and VivaxGEN networks is driven by our collective goal to advance research into the complex biology of P. vivax and to accelerate genomic surveillance for malaria control and elimination.

Anti-Gametocyte Antigen Humoral Immunity and Gametocytemia During Treatment of Uncomplicated Falciparum Malaria: A Multi-National Study

Introduction

Understanding the human immune response to Plasmodium falciparum gametocytes and its association with gametocytemia is essential for understanding the transmission of malaria as well as progressing transmission blocking vaccine candidates.

Methods

In a multi-national clinical efficacy trial of artemisinin therapies (13 sites of varying transmission over South-East Asia and Africa), we measured Immunoglobulin G (IgG) responses to recombinant P. falciparum gametocyte antigens expressed on the gametocyte plasma membrane and leading transmission blocking vaccine candidates Pfs230 (Pfs230c and Pfs230D1M) and Pfs48/45 at enrolment in 1,114 participants with clinical falciparum malaria. Mixed effects linear and logistic regression were used to determine the association between gametocyte measures (gametocytemia and gametocyte density) and antibody outcomes at enrolment.

Results

Microscopy detectable gametocytemia was observed in 11% (127/1,114) of participants at enrolment, and an additional 9% (95/1,114) over the follow-up period (up to day 42) (total 20% of participants [222/1,114]). IgG levels in response to Pfs230c, Pfs48/45 and Pfs230D1M varied across study sites at enrolment (p < 0.001), as did IgG seroprevalence for anti-Pfs230c and D1M IgG (p < 0.001), but not for anti-Pfs48/45 IgG (p = 0.159). In adjusted analyses, microscopy detectable gametocytemia at enrolment was associated with an increase in the odds of IgG seropositivity to the three gametocyte antigens (Pfs230c OR [95% CI], p: 1.70 [1.10, 2.62], 0.017; Pfs48/45: 1.45 [0.85, 2.46], 0.174; Pfs230D1M: 1.70 [1.03, 2.80], 0.037), as was higher gametocyte density at enrolment (per two-fold change in gametocyte density Pfs230c OR [95% CI], p: 1.09 [1.02, 1.17], 0.008; Pfs48/45: 1.05 [0.98, 1.13], 0.185; Pfs230D1M: 1.07 [0.99, 1.14], 0.071).

Conclusion

Pfs230 and Pfs48/45 antibodies are naturally immunogenic targets associated with patent gametocytemia and increasing gametocyte density across multiple malaria endemic settings, including regions with emerging artemisinin-resistant P. falciparum.

688 Cancellation Rate of Prostate Template Biopsy: Are There Any Merits to Implementing Pre-Operative Bowel Preparations?

Introduction

The aim of this quality improvement project was to analyse the cancellation rates of the template biopsy done at the George Eliot Hospital. The focus was mainly on those due to poor bowel prep whereby manual evacuations have failed. Locally we have sometimes noted the failure rate of transperineal prostate biopsy as a result of the poor quality of the ultrasound due to inadequately evacuated rectum. Unfortunately, there are very limited studies which have looked into this issue hence the significance of this problem is not universally acknowledged.

Method

Retrospective review of all the template biopsies that were planned from April 2019 to April 2020 using the operation notes and local theatre management software.

Results

There was a total of 105 planned template biopsies from April 2019 to April 2020. 72 cases were attempted and within this, 7 of these cases required manual evacuations in which 3 resulted in abandonment of procedure. There were 33 cases which were cancelled due various other reasons.

Conclusions

The results showed that the failure rates due to poor bowel prep were not significant (4%). Based on these findings we have decided not to proceed with the implementation of pre-operative bowel prep with phosphate enema as we felt that the potential benefits were not enough for it be initiated as a routine practice. We aim to address the other reasons identified for cancellations.

An open dataset of Plasmodium falciparum genome variation in 7,000 worldwide samples

MalariaGEN is a data-sharing network that enables groups around the world to work together on the genomic epidemiology of malaria. Here we describe a new release of curated genome variation data on 7,000 Plasmodium falciparum samples from MalariaGEN partner studies in 28 malaria-endemic countries. High-quality genotype calls on 3 million single nucleotide polymorphisms (SNPs) and short indels were produced using a standardised analysis pipeline. Copy number variants associated with drug resistance and structural variants that cause failure of rapid diagnostic tests were also analysed.  Almost all samples showed genetic evidence of resistance to at least one antimalarial drug, and some samples from Southeast Asia carried markers of resistance to six commonly-used drugs. Genes expressed during the mosquito stage of the parasite life-cycle are prominent among loci that show strong geographic differentiation. By continuing to enlarge this open data resource we aim to facilitate research into the evolutionary processes affecting malaria control and to accelerate development of the surveillance toolkit required for malaria elimination.

An open dataset of Plasmodium falciparum genome variation in 7,000 worldwide samples

MalariaGEN is a data-sharing network that enables groups around the world to work together on the genomic epidemiology of malaria. Here we describe a new release of curated genome variation data on 7,000 Plasmodium falciparum samples from MalariaGEN partner studies in 28 malaria-endemic countries. High-quality genotype calls on 3 million single nucleotide polymorphisms (SNPs) and short indels were produced using a standardised analysis pipeline. Copy number variants associated with drug resistance and structural variants that cause failure of rapid diagnostic tests were also analysed.  Almost all samples showed genetic evidence of resistance to at least one antimalarial drug, and some samples from Southeast Asia carried markers of resistance to six commonly-used drugs. Genes expressed during the mosquito stage of the parasite life-cycle are prominent among loci that show strong geographic differentiation. By continuing to enlarge this open data resource we aim to facilitate research into the evolutionary processes affecting malaria control and to accelerate development of the surveillance toolkit required for malaria elimination.

Therapeutic efficacy of artemether-lumefantrine and artesunate-amodiaquine for the treatment of uncomplicated Plasmodium falciparum malaria in Mali, 2015-2016

BACKGROUND

The current first-line treatments for uncomplicated malaria recommended by the National Malaria Control Programme in Mali are artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ). From 2015 to 2016, an in vivo study was carried out to assess the clinical and parasitological responses to AL and ASAQ in Sélingué, Mali.

METHODS

Children between 6 and 59 months of age with uncomplicated Plasmodium falciparum infection and 2000-200,000 asexual parasites/μL of blood were enrolled, randomly assigned to either AL or ASAQ, and followed up for 42 days. Uncorrected and PCR-corrected efficacy results at days 28 and 42. were calculated. Known markers of resistance in the Pfk13, Pfmdr1, and Pfcrt genes were assessed using Sanger sequencing.

RESULTS

A total of 449 patients were enrolled: 225 in the AL group and 224 in the ASAQ group. Uncorrected efficacy at day 28 was 83.4% (95% CI 78.5-88.4%) in the AL arm and 93.1% (95% CI 89.7-96.5%) in the ASAQ arm. The per protocol PCR-corrected efficacy at day 28 was 91.0% (86.0-95.9%) in the AL arm and 97.1% (93.6-100%) in the ASAQ arm. ASAQ was significantly (p < 0.05) better than AL for each of the aforementioned efficacy outcomes. No mutations associated with artemisinin resistance were identified in the Pfk13 gene. Overall, for Pfmdr1, the N86 allele and the NFD haplotype were the most common. The NFD haplotype was significantly more prevalent in the post-treatment than in the pre-treatment isolates in the AL arm (p < 0.01) but not in the ASAQ arm. For Pfcrt, the CVIET haplotype was the most common.

CONCLUSIONS

The findings indicate that both AL and ASAQ remain effective for the treatment of uncomplicated malaria in Sélingué, Mali.

Microdiversity of Enterococcus faecalis isolates in cases of infective endocarditis: selection of non-synonymous mutations and large deletions is associated with phenotypic modifications

Context: Today, infective endocarditis (IE) caused by Enterococcus faecalis represents 10% of all IE and is marked by its difficult management and the frequency of relapses. Although the precise reasons for that remain to be elucidated, the evolution of the culprit strain under selective pressure through microdiversification could be, at least in part, involved. Material and methods: To further study the in situ genetic microdiversity and its possible phenotypic manifestations in E. faecalis IE, we sequenced and compared multiple isolates from the valves, blood culture and joint fluid of five patients who underwent valvular surgery. Growth rate and early biofilm production of selected isolates were also compared. Results: By sequencing a total of 58 E. faecalis genomes, we detected a considerable genomic microdiversity, not only among strains from different anatomical origins, but also between isolates from the same studied cardiac valves. Interestingly, deletions of thousands of bases including the well-known virulence factors ebpA/B/C, and srtC, as well as other large prophage sequences containing genes coding for proteins implicated in platelet binding (PlbA and PlbB) were evidenced. The study of mutations helped unveil common patterns in genes related to the cell cycle as well as central metabolism, suggesting an evolutionary convergence in these isolates. As expected, such modifications were associated with a significant impact on the in-vitro phenotypic heterogeneity, growth, and early biofilm production. Conclusion: Genome modifications associated with phenotypic variations may allow bacterial adaptation to both antibiotic and immune selective pressures, and thus promote relapses.

A structured pathway for developing your complex abdominal hernia service: our York pathway

PURPOSE

Clinical pathways are widely prevalent in health care and may be associated with increased clinical efficacy, improved patient care, streamlining of services, while providing clarity on patient management. Such pathways are well established in several branches of healthcare services but, to the authors' knowledge, not in complex abdominal wall reconstruction (CAWR). A stepwise, structured and comprehensive approach to managing complex abdominal wall hernia (CAWH) patients, which has been successfully implemented in our practice, is presented.

METHODS

A literature search of common databases including Embase® and MEDLINE® for CAWH pathways identified no comprehensive pathway. We therefore undertook a reiterative process to develop the York Abdominal Wall Unit (YAWU) through examination of current evidence and logic to produce a pragmatic redesign of our own pathway. Having introduced our pathway, we then performed a retrospective analysis of the complexity and number of abdominal wall cases performed in our trust over time.

RESULTS

We describe our pathway and demonstrate that the percentage of cases and their complexity, as defined by the VHWG classification, have increased over time in York Abdominal Wall Unit.

CONCLUSION

A structured pathway for complex abdominal wall hernia service is one way to improve patient experience and streamline services. The relevance of pathways for the hernia surgeon is discussed alongside this pathway. This may provide a useful guide to those wishing to establish similar personalised pathways within their own units and allow them to expand their service.

[SARS-COV-2 myocarditis. An update]

The outbreak of the SARS-CoV-2 virus responsible for the COVID-19 disease has given rise to a new disease whose boundaries are still to be discovered. While the first data suggested a purely respiratory infection, the most recent publications highlight a large pleomorphism of the disease, responsible for multiple organ damage, of which cardiac injury seems to be the most represented. This cardiac injury can present as acute myocarditis. Our aim was to discuss the pathophysiological rationale underlying the existence of SARS-CoV-2 myocarditis and to analyze the literature data regarding the diagnosis and treatment of this particular entity.

Correlates and prognostic impact of acute heart failure at the acute stage of ST-elevation and non-ST-elevation myocardial infarction according to diabetic status: the FAST-MI registries

Background

Diabetes mellitus (DM) predisposes to cardiovascular diseases including acute myocardial infarction (AMI) and acute heart failure (AHF).

Purpose

Analysing the French Registries of Acute ST-elevation and non-ST-elevation Myocardial Infarction (FAST-MI) 2005 and 2010, we assessed correlates of AHF occurring at the acute stage of ST-elevation AMI (STEMI) and non-ST-elevation AMI (NSTEMI), as well as the prognostic impact of AHF on 5-year mortality according to diabetic status.

Methods

The FAST-MI 2005 and 2010 registries included 7,839 consecutive patients admitted for AMI (4,250 STEMI and 3,589 NSTEMI). Vital status at 5 years was available in &gt;96% of the patients. Binary logistic regression analysis was used to determine independent correlates of AHF and Cox multivariate analysis was used to determine independent correlates of 5-year mortality. Long-term survival curves were estimated using the Kaplan Meier method and comparisons were made using log-rank tests.

Results

2,151 patients presented with DM (27,4%) and 629 patients (8,0%) were treated by insulin (DMi). DM patients were older (70.0 vs. 64.6 years; p&lt;0.001), with more comorbidities and more severe coronary artery disease. AHF (pulmonary edema or cardiogenic shock) was the most frequent in-hospital complication (12.5%) and was twice as frequent in DM patients (20.2% vs. 9.6%; adjusted OR=1.66; 95% confidence interval: 1.43–1.94; P&lt;0.001). AHF was more frequently observed in DM patients on insulin therapy compared with DM patients not receiving insulin (29.1% vs 16.6%; adjusted OR=1.53; 95% CI: 1.20–1.96; P=0.001). The significant difference in AHF between DM patients and patients without DM was found in both STEMI (18.8% vs 8.0%; P=0.001) and in NSTEMI (21.3% vs 11.9%; P=0.001) patients.

After multivariate analysis on confounders (risk factors, previous medical history, type of AMI, year of survey and medications used before the index AMI), compared with patients without DM nor AHF, those with AHF without DM and those with DM without AHF had a 50% increase in 5-year mortality (adjusted HR=1.50; 95% CI: 1.32–1.69; P&lt;0.001 and adjusted HR=1.46; 95% CI: 1.23–1.74; P&lt;0.001) while the risk of 5-year death was doubled in those with both DM and AHF (adjusted HR=1.97; 95% CI: 1.66–2.34; P&lt;0.0001).

Conclusion

AHF is the most frequent complication of AMI and is twice as common in DM patients. It is associated with reduced 5-year survival in non-diabetic and DM patients, with the worst outcomes in patients with both conditions (AHF and DM). In AMI, new management strategies are needed to prevent AHF and improve survival in DM patients with AHF.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The FAST-MI 2005 and 2010 registries are the propriety of the French Society of Cardiology and were funded by grants from the following companies: Amgen, AstraZeneca, Bayer, BMS, Daiichi-Sankyo, Eli-Lilly, GSK, MSD, Novartis, Pfizer, Sanofi, and Servier, and by a grant from the French National Health Insurance body (CNAM-TS).

A multistage process leading to the development of a structured consent form and patient information leaflet for complex abdominal wall reconstruction (CAWR)

PURPOSE

Informed consent is vital in surgery. The General Medical Council, UK and Royal College of Surgeons of England provide clear guidance on what constitutes the process of informed patient consent. Despite this, evidence suggests that the consent process may not be performed well in surgery. We utilised a staged patient-centred approach and rigorous methodology to develop a standardised patient information leaflet (PIL) and pre-written structured consent form for complex abdominal wall reconstruction (CAWR).

METHODS

We utilised the principles of Deming's Plan-Do-Study-Act (PDSA) cycles to approach the process. Buzan's mind maps were used to identify the stakeholders and deficiencies in the consent process ('Plan' phase). The content of the PIL and pre-written consent form was then developed in collaboration with stakeholders ('Do' phase). Multidisciplinary and multidepartmental feedback was obtained on the proposed content and amendments were made ('Study' and 'Act' phases).

RESULTS

We successfully produced a clear, focused PIL and structured consent form, in Plain English, presenting accurate, relevant and detailed information in a highly understandable way. The PIL had a Flesch Reading Ease score of > 80, demonstrating a high level of readability and comprehensibility, with positive implications for informed patient decision making and preparedness for surgery.

CONCLUSION

Through sharing the process that we undertook, we aim to support other abdominal wall units who wish to develop and improve their own consent process.

Contribution of Functional Antimalarial Immunity to Measures of Parasite Clearance in Therapeutic Efficacy Studies of Artemisinin Derivatives

Background

Antibodies to the blood stages of malaria parasites enhance parasite clearance and antimalarial efficacy. The antibody subclass and functions that contribute to parasite clearance during antimalarial treatment and their relationship to malaria transmission intensity have not been characterized.

Methods

Levels of immunoglobulin G (IgG) subclasses and C1q fixation in response to Plasmodium falciparum merozoite antigens (erythrocyte-binding antigen [EBA] 175RIII-V, merozoite surface protein 2 [MSP-2], and MSP-142) and opsonic phagocytosis of merozoites were measured in a multinational trial assessing the efficacy of artesunate therapy across 11 Southeast Asian sites. Regression analyses assessed the effects of antibody seropositivity on the parasite clearance half-life (PC_½), having a PC_½ of ≥5 hours, and having parasitemia 3 days after treatment.

Results

IgG3, followed by IgG1, was the predominant IgG subclass detected (seroprevalence range, 5%–35% for IgG1 and 27%–41% for IgG3), varied across study sites, and was lowest in study sites with the lowest transmission intensity and slowest mean PC_½. IgG3, C1q fixation, and opsonic-phagocytosis seropositivity were associated with a faster PC_½ (range of the mean reduction in PC_½, 0.47–1.16 hours; P range, .001–.03) and a reduced odds of having a PC_½ of ≥5 hours and having parasitemia 3 days after treatment.

Conclusions

The prevalence of IgG3, complement-fixing antibodies, and merozoite phagocytosis vary according to transmission intensity, are associated with faster parasite clearance, and may be sensitive surrogates of an augmented clearance capacity of infected erythrocytes. Determining the functional immune mechanisms associated with parasite clearance will improve characterization of artemisinin resistance.

Evaluation of dual energy CT and iterative metal artefact reduction (iMAR) for artefact reduction in radiation therapy

Metal artefacts pose a common problem in single energy computed tomography (SECT) images used for radiotherapy. Virtual monoenergetic (VME) images constructed with dual energy computed tomography (DECT) scans can be used to reduce beam hardening artefacts. Dual energy metal artefact reduction is compared and combined with iterative metal artefact reduction (iMAR) to determine optimal imaging strategies for patients with metal prostheses. SECT and DECT scans were performed on a Siemens Somatom AS-64 Slice CT scanner. Images were acquired of a modified CIRS pelvis phantom with 6, 12, 20 mm diameter stainless steel rods and VME images reconstructed at 100, 120, 140 and 190 keV. These were post-reconstructed with and without the iMAR algorithm. Artefact reduction was measured using: (1) the change in Hounsfield Unit (HU) with and without metal artefact reduction (MAR) for 4 regions of interest; (2) the total number of artefact pixels, defined as pixels with a difference (between images with metal rod and without) exceeding a threshold; (3) the difference in the mean pixel intensity of the artefact pixels. DECT, SECT + iMAR and DECT + iMAR were compared. Both SECT + iMAR and DECT + iMAR offer successful MAR for phantom simulating unilateral hip prosthesis. DECT gives minimal artefact reduction over iMAR alone. Quantitative metrics are advantageous for MAR analysis but have limitations that leave room for metric development.

Randomized controlled study of the prediction of diminutive/small colorectal polyp histology using didactic versus computer-based self-learning module in gastroenterology trainees

BACKGROUND AND AIM

The aim of this randomized trial was to evaluate the performance of self-training versus didactic training in order to increase the diagnostic accuracy of diminutive/small colonic polyp histological prediction by trainees.

METHODS

Sixteen trainees reviewed 78 videos (48 iSCAN-OE and 30 NBI) of diminutive/small polyps in a pretraining assessment. Trainees were randomized to receive computer-based self-learning (n = 8) or didactic training (n = 8) using identical teaching materials and videos. The same 78 videos, in a different randomized order, were assessed. The NICE (NBI International Colorectal Endoscopic) and SIMPLE (Simplified Identification Method for Polyp Labeling during Endoscopy) classification systems were used to classify diminutive/small polyps.

RESULTS

A higher proportion of high-confidence predictions of polyps was made by the self-training group versus the didactic group using both the SIMPLE classification (77.1% [95% CI 73.4-80.3] vs 69.9% [95% CI 66.1-73.5%] [P = 0.005]) and the NICE classification (77% [95% CI 73.2-80.4%] vs 69.8% [95% CI 66-73.4%] [P = 0.006]). When using NICE, sensitivity of the self-training group compared with the didactic group was 72% versus 83% (P = 0.0005), and the accuracy was 66.1% versus 69.1%. The training improved the confidence of participants and SIMPLE was preferred over NICE.

CONCLUSION

Self-learning for the prediction of diminutive/small polyp histology is a method of training that can achieve results similar to didactic training. Availability of adequate self-learning teaching modules could enable widespread implementation of optical diagnosis in clinical practice.

Effect of Supportive Supervision on Malaria Microscopy Competencies in Sub-Saharan Africa

Although light microscopy is the reference standard for diagnosing malaria, maintaining skills over time can be challenging. Between 2015 and 2017, the U.S. President's Malaria Initiative-funded MalariaCare project supported outreach training and supportive supervision (OTSS) visits at 1,037 health facilities in seven African countries to improve performance in microscopy slide preparation, staining, and reading. During these visits, supervisors observed and provided feedback to health-care workers (HCWs) performing malaria microscopy using a 30-step checklist. Of the steps observed in facilities with at least three visits, the proportion of HCWs that performed each step correctly at baseline ranged from 63.2% to 94.2%. The change in the proportion of HCWs performing steps correctly by the third visit ranged from 16.7 to 23.6 percentage points (n = 916 observations). To assess the overall improvement, facility scores were calculated based on the steps performed correctly during each visit. The mean score at baseline was 85.7%, demonstrating a high level of performance before OTSS. Regression analysis predicted an improvement in facility scores of 3.6 percentage points (P < 0.001) after three visits across all countries. In reference-level facilities with consistently high performance on microscopy procedures and parasite detection, quality assurance (QA) mechanisms could prioritize more advanced skills, such as proficiency testing for parasite counting and species identification. However, in settings with high staff turnover and declining use of microscopy in favor of rapid diagnostic tests, additional supervision visits and/or additional QA measures may be required to improve and maintain performance.

A single nucleotide polymorphism in the Plasmodium falciparum atg18 gene associates with artemisinin resistance and confers enhanced parasite survival under nutrient deprivation

Background

Artemisinin-resistant Plasmodium falciparum has been reported throughout the Greater Mekong subregion and threatens to disrupt current malaria control efforts worldwide. Polymorphisms in kelch13 have been associated with clinical and in vitro resistance phenotypes; however, several studies suggest that the genetic determinants of resistance may involve multiple genes. Current proposed mechanisms of resistance conferred by polymorphisms in kelch13 hint at a connection to an autophagy-like pathway in P. falciparum.

Results

A SNP in autophagy-related gene 18 (atg18) was associated with long parasite clearance half-life in patients following artemisinin-based combination therapy. This gene encodes PfAtg18, which is shown to be similar to the mammalian/yeast homologue WIPI/Atg18 in terms of structure, binding abilities, and ability to form puncta in response to stress. To investigate the contribution of this polymorphism, the atg18 gene was edited using CRISPR/Cas9 to introduce a T38I mutation into a k13-edited Dd2 parasite. The presence of this SNP confers a fitness advantage by enabling parasites to grow faster in nutrient-limited settings. The mutant and parent parasites were screened against drug libraries of 6349 unique compounds. While the SNP did not modulate the parasite’s susceptibility to any of the anti-malarial compounds using a 72-h drug pulse, it did alter the parasite’s susceptibility to 227 other compounds.

Conclusions

These results suggest that the atg18 T38I polymorphism may provide additional resistance against artemisinin derivatives, but not partner drugs, even in the absence of kelch13 mutations, and may also be important in parasite survival during nutrient deprivation.

Electronic supplementary material

The online version of this article (10.1186/s12936-018-2532-x) contains supplementary material, which is available to authorized users.

Synthesis and Study of the Antimalarial Cardamom Peroxide

A full account of our previously disclosed synthesis of the monoterpene dimer cardamom peroxide is reported. Inspired by hypotheses regarding the potential biosynthetic origins of this natural product, several unproductive routes are also reported. The chemical reactivity of this structurally unique metabolite in the presence of iron(II) sources is also reported as is its antimalarial activity against Plasmodium falciparum clinical isolates from several Cambodian provinces.

Plasmepsin II-III copy number accounts for bimodal piperaquine resistance among Cambodian Plasmodium falciparum

Multidrug resistant Plasmodium falciparum in Southeast Asia endangers regional malaria elimination and threatens to spread to other malaria endemic areas. Understanding mechanisms of piperaquine (PPQ) resistance is crucial for tracking its emergence and spread, and to develop effective strategies for overcoming it. Here we analyze a mechanism of PPQ resistance in Cambodian parasites. Isolates exhibit a bimodal dose-response curve when exposed to PPQ, with the area under the curve quantifying their survival in vitro. Increased copy number for plasmepsin II and plasmepsin III appears to explain enhanced survival when exposed to PPQ in most, but not all cases. A panel of isogenic subclones reinforces the importance of plasmepsin II-III copy number to enhanced PPQ survival. We conjecture that factors producing increased parasite survival under PPQ exposure in vitro may drive clinical PPQ failures in the field.

Origins of the current outbreak of multidrug-resistant malaria in southeast Asia: a retrospective genetic study

BACKGROUND

Antimalarial resistance is rapidly spreading across parts of southeast Asia where dihydroartemisinin-piperaquine is used as first-line treatment for Plasmodium falciparum malaria. The first published reports about resistance to antimalarial drugs came from western Cambodia in 2013. Here, we analyse genetic changes in the P falciparum population of western Cambodia in the 6 years before those reports.

METHODS

We analysed genome sequence data on 1492 P falciparum samples from 11 locations across southeast Asia, including 464 samples collected in western Cambodia between 2007 and 2013. Different epidemiological origins of resistance were identified by haplotypic analysis of the kelch13 artemisinin resistance locus and the plasmepsin 2-3 piperaquine resistance locus.

FINDINGS

We identified more than 30 independent origins of artemisinin resistance, of which the KEL1 lineage accounted for 140 (91%) of 154 parasites resistant to dihydroartemisinin-piperaquine. In 2008, KEL1 combined with PLA1, the major lineage associated with piperaquine resistance. By 2013, the KEL1/PLA1 co-lineage had reached a frequency of 63% (24/38) in western Cambodia and had spread to northern Cambodia.

INTERPRETATION

The KEL1/PLA1 co-lineage emerged in the same year that dihydroartemisinin-piperaquine became the first-line antimalarial drug in western Cambodia and spread rapidly thereafter, displacing other artemisinin-resistant parasite lineages. These findings have important implications for management of the global health risk associated with the current outbreak of multidrug-resistant malaria in southeast Asia.

FUNDING

Wellcome Trust, Bill & Melinda Gates Foundation, Medical Research Council, UK Department for International Development, and the Intramural Research Program of the National Institute of Allergy and Infectious Diseases.