Improved Characterization of Soil Organic Matter by Integrating FT-ICR MS, Liquid Chromatography Tandem Mass Spectrometry, and Molecular Networking: A Case Study of Root Litter Decay under Drought Conditions.

Understanding of how soil organic matter (SOM) chemistry is altered in a changing climate has advanced considerably; however, most SOM components remain unidentified, impeding the ability to characterize a major fraction of organic matter and predict what types of molecules, and from which sources, will persist in soil. We present a novel approach to better characterize SOM extracts by integrating information from three types of analyses, and we deploy this method to characterize decaying root-detritus soil microcosms subjected to either drought or normal conditions. To observe broad differences in composition, we employed direct infusion Fourier-transform ion cyclotron resonance mass spectrometry (DI-FT-ICR MS). We complemented this with liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify components by library matching. Since libraries contain only a small fraction of SOM components, we also used fragment spectral cosine similarity scores to relate unknowns and library matches through molecular networks. This integrated approach allowed us to corroborate DI-FT-ICR MS molecular formulas using library matches, which included fungal metabolites and related polyphenolic compounds. We also inferred structures of unknowns from molecular networks and improved LC-MS/MS annotation rates from ∼5 to 35% by considering DI-FT-ICR MS molecular formula assignments. Under drought conditions, we found greater relative amounts of lignin-like vs condensed aromatic polyphenol formulas and lower average nominal oxidation state of carbon, suggesting reduced decomposition of SOM and/or microbes under stress. Our integrated approach provides a framework for enhanced annotation of SOM components that is more comprehensive than performing individual data analyses in parallel.

Systematic Review and Meta-analysis of the Impact of Surgeon-Physician Co-management Models on Short Term Outcomes for Vascular Surgery Inpatients.

OBJECTIVE: As the population ages, vascular surgeons are treating progressively older, multimorbid patients at risk of peri-operative complications. An embedded physician has been shown to improve outcomes in general and orthopaedic surgery. This systematic review and meta-analysis aimed to investigate the impact of surgeon-physician co-management models on morbidity and mortality rates in vascular inpatients. DATA SOURCES: PubMed, Scopus, Embase, conference abstract listings, and clinical trial registries. REVIEW METHODS: Studies comparing adult vascular surgery inpatients under co-management with standard of care were eligible. The relative risks (RRs) of death, medical complications, and 30 day re-admission between co-management and standard care were calculated. The effect of co-management on the mean length of stay was calculated using weighted means. Risk of bias was assessed using the Methodological Index for Non-Randomised Studies, and certainty assessment with the GRADE analysis tools. RESULTS: No randomised controlled trials were identified. Eight single institution studies between 2011 and 2020 with 7 410 patients were included. All studies were observational using before-after methodology. Studies were of high to moderate risk of bias, and outcomes were of very low GRADE certainty of evidence. Co-management was associated with a statistically significant lower relative risk of death (RR 0.64, 95% confidence interval [CI] 0.44 - 0.92; p = .02), cardiac complications (RR 0.47, 95% CI 0.25 - 0.87; p = .02), and infective complications (RR 0.49, 95% CI 0.35 - 0.67; p < .001) in vascular inpatients. No statistically significant differences in length of stay (standard mean difference -0.6 days, 95% CI -1.44 - 0.24 days; p = .16) and 30 day re-admission (RR 0.96, 95% CI 0.84 - 1.08; p = .49) were noted. CONCLUSION: Early results of physician and surgeon co-management for vascular surgery inpatients showed promising results from very low certainty data. Further well designed, prospective studies are needed to determine how to maximise the impact of physicians within a vascular service to improve patient outcomes while using hospital resources effectively.

Pharmacological Thromboprophylaxis for VTE Post-Endovenous Ablation of Varicose Veins: Network Meta-Analysis.

OBJECTIVE: Endovenous ablation has revolutionized treatment of varicose vein surgery but is associated with a risk of venous thromboembolism. There is no consensus regarding anticoagulation protocols for these patients. This network meta-analysis (NMA) aims to identify which anticoagulant is optimal in this cohort for clot prevention with minimal risk of adverse bleeding events. METHODS: Library databases were searched for studies where patients were treated with one or more anticoagulants following endovenous ablation for varicose veins. The methodological quality of included studies was quantified using the Risk of Bias (ROB) assessment tools. Findings were reported using the meta-analysis of observational studies in epidemiology (MOOSE) checklist. Statistical analysis was carried out using metainsight (rpackage). RESULTS: Observational data on just under 1500 patients prescribed post ablation anticoagulation (Rivaroxaban, Enoxaparin, Fondaparinux) were analyzed. Patient characteristics were comparable across the cohorts. 81 thrombotic and 40 minor bleeding events occurred in total. Overall rivaroxaban is found to be superior to the other agents. CONCLUSIONS: This NMA indicates that prophylactic rivaroxaban is the highest ranked anticoagulant for thromboprophylaxis in patients post endovenous ablation for varicose veins, with a low risk of adverse bleeding. The choice whether to anticoagulate these patients is likely to remain at the discretion of the treating clinician.

An exploratory view into allelic drop-out of sequenced autosomal STRs.

As massively parallel sequencing is implemented in forensic genetics, an understanding of sequence data must accompany these advancements, that is, accurate modeling of data for proper statistical analysis. Allelic drop-out, a common stochastic effect seen in genetic data, is often modeled in statistical analysis of STR results. This proof-of-concept study sequenced several serial dilutions of a standard sample ranging from 4 ng to 7.82 pg to evaluate allelic drop-out trends on a select panel of autosomal STRs using the ForenSeq™ DNA Signature Prep Kit, Primer Set A on the Illumina MiSeq FGx. Parameters assessed included locus, profile, and run specific information. A majority of the allelic drop-out occurred in DNA concentrations less than 31.25 pg. Statistical results indicated a need for locus-specific modeling based on STR descriptors, like simple versus compound repeat patterns. No correlation was seen between average read count of scored alleles and allelic drop-out at a locus. A statistical correlation was observed between the amount of allelic drop-out and the starting amount of DNA in a sample, average read count of a sample, and total read count generated on a flow cell. This study supports using common allelic drop-out factors used in fragment length analysis on sequenced STRs while including additional locus, sample, and run specific information. Results demonstrate multiple factors that can be considered when developing probability of allelic drop-out models for sequenced autosomal STRs including locus-specific analysis, total read count of a profile, and total read count sequenced on a flow cell.

Applied Biosystems™ PrepFiler™ Forensic DNA Extraction Kit (Manual and Semi-automated via AutoMate Express™).

The PrepFiler™ Forensic DNA Extraction Kits allow for optimal genomic DNA isolation and purification from forensic samples through a bind-wash-elute-based technique that can be performed manually or robotically using the Applied Biosystems AutoMate Express™ Forensic DNA Extraction System. The extraction kits come in two formats: the standard kit used for common case type samples, like bodily fluid swabs or stains, and a BTA kit for more challenging evidence sample types that can be submitted for analysis, like bones, teeth, and adhesive-type samples. Both forms of extraction, manual and semi-automated, require an initial manual incubation step using a lysis buffer to release the DNA into solution. If following the semi-automated protocol, the lysate can be purified and eluted on the AutoMate Express™. After lysis, the DNA binds to magnetic beads in the presence of a chaotropic salt and is washed multiple times with an ethanol-based wash buffer to purify the sample and remove potential PCR inhibitors. After removing the wash liquid, elution buffer is added to the tube containing the DNA-bound magnetic beads and heated, which disrupts the bonding between the DNA and beads. The DNA is then concentrated in the final tube and can be moved forward through the DNA analysis workflow. This chapter describes a manual DNA isolation method and the extraction procedures following both manual and robotic methods using the PrepFiler™ chemistries in conjunction with the AutoMate Express™ Forensic DNA Extraction System.

Applied Biosystems' GlobalFiler™ PCR Amplification Kit.

The GlobalFiler™ PCR Amplification Kit is one of the most sensitive kits that exist today that makes the PCR amplification of human DNA possible. PCR amplification using this specific kit makes millions of copies of 24 specific target sequences in the DNA, called markers or loci. This kit is a 6-dye, short tandem repeat (STR) multiplex assay kit that has a synthetic mix of primers and single-stranded oligonucleotides that are combined with DNA samples and then subjected to 29 or 30 cycles of denaturing, annealing, and extension, as per laboratory protocol. Methods for instrument operation will vary depending on the thermal cycler instrument model that is used. Nevertheless, the GlobalFiler™ PCR Amplification Kit has proven to be a very useful tool to DNA analysts, amplifying extremely low quantities of DNA, making it possible to detect partial, if not full, genetic profiles from a wide range of sample types. This chapter discusses the typical preparation and PCR amplification of human forensic DNA samples, using the GlobalFiler™ PCR Amplification Kit.

Likelihood Ratio Calculation Using LRmix Studio.

LRmix Studio performs statistical analyses on forensic casework samples by calculating a likelihood ratio (LR) following a semi-continuous, unrestricted approach. The software utilizes a basic probabilistic model allowing the comparison of two alternative hypotheses regarding the evidence profile to include known and/or unknown contributors, for a maximum of a 4-person mixture. Other statistical factors that are included in this model are the incorporation of multiple probability of drop-out values, probability of drop-in, a correction factor for population substructure, assumed contributor inclusion, and inclusion of an unknown relative in the defense hypothesis. A range of plausible probability of drop-out values can be calculated for various contributors and hypotheses based on a Monte Carlo probability method and included in the likelihood ratio calculation. The software also includes several ways to test the validity and robustness of the probabilistic model. A sensitivity analysis can be performed by calculating likelihood ratios for the given profile against a range of drop-out values. Additionally, a non-contributor test can be performed on the crime scene sample and the chosen LR parameters to test the robustness of the model. This can give a point of comparison of the likelihood ratio generated for the person of interest (POI) compared to "random man" profiles generated from uploaded allelic frequencies. Finally, the analysis can be printed in a well-structured and user-friendly report that includes all analysis parameters. Within this chapter, the reader will learn the steps to calculate a likelihood ratio using the semi-continuous software, LRmix Studio. Additional tools supplied through the software will also be explained and demonstrated.

Rapid DNA Profile Development with Applied Biosystems RapidHIT™ ID System.

The RapidHIT™ ID System by Applied Biosystems allows the generation of a CODIS compatible STR profile in 90 min. The preloaded cartridges, fully automated workflow, and user-friendly computer interface allow for quick and simple single sample processing both in the laboratory and outside by non-laboratory personnel, like law enforcement officers. DNA processing utilizes a direct amplification workflow to generate an STR profile targeting the CODIS or ESS core loci. In conjunction with the RapidLINK™ Software, the system performs an initial analysis, flagging any profiles that do not meet single-source full profile parameters. Additionally, the RapidLINK™ allows for users to manage a multi-instrument/multi-location Rapid DNA system and view results in real-time. This gives users off-site the ability to track and even analyze results. The system allows for rapid reference sample analysis in locations like booking stations and national or border security agencies to obtain quick feedback of database hits for investigative leads while the subject is still in custody. RapidHIT™ ID DNA systems can also be set up at sites to aid in victim identification during mass disasters. The following chapter describes the process of generating a forensic DNA profile using the RapidHIT™ ID instrumentation from start to finish. Additionally, basic use and analysis using the RapidLINK™ and GeneMarker™ HID software is included.

Next-Generation Sequencing: ForenSeq™ DNA Signature Prep Kit with the Illumina MiSeq FGx.

Sequencing forensic DNA samples that are amplified and prepared with the ForenSeq™ DNA Signature Prep Kit allows for the simultaneous targeting of forensically relevant STR and SNP markers. The MiSeq™ FGx system allows massively parallel sequencing of these markers in a single analysis. The library preparation targets autosomal, Y-, and X-STRs, as well as identity SNPs. The kit can also be used to generate investigative information regarding the DNA contributor by analyzing phenotypic SNPs to predict hair color, eye color, and ancestry SNPs.Through two rounds of amplification, all loci are amplified and tagged with individualizing barcodes for sequencing capture and identification. Using bead-based technology, the libraries are purified by the removal of left-over amplification reagents and then normalized to ensure equal representation of all samples during sequencing. The individual libraries are then pooled for insertion into the MiSeq FGx. The pooled libraries are then added to a pre-packaged cartridge that contains all reagents necessary for optimal sequencing. Libraries are captured on a flow cell and undergo bridge amplification for the generation of individual clusters. Sequencing of each cluster is performed using a Sequence-By-Synthesis technology. The following chapter describes the methodology and process of library preparation of samples using the ForenSeq™ DNA Signature Prep Kit Primer Set A and B. Once completed, the chapter then focuses on the setup of a sequencing run on the MiSeq FGx and the sequencing methodology employed by the instrument.

An audit of secondary prevention for peripheral arterial disease in primary care - scope for improved collaboration between vascular surgery and general practitioners.

BACKGROUND: Symptomatic peripheral arterial disease (PAD) is a common cause for referral from primary care to vascular surgery. Best medical therapy (BMT), encompassing anti-platelets, statins, smoking cessation, blood pressure and glycaemic control, is a cornerstone of PAD management. However, these easily modifiable risk factors are often left unaddressed between referral and clinic review. METHODS: A prospective audit of electronic 'Healthlink' referrals by GPs to the vascular department for symptomatic PAD between July 2021 and June 2022 was performed. Referrals were individually reviewed for demographics, symptoms, medical history, smoking status and medications. An information leaflet on BMT was posted to all GP practices in the Soalta region as part of an educational intervention, with plans to re-audit after 6 months. RESULTS: One-hundred-and-seventy referrals were analysed. The median age was 68.5 years (range 33-94) and 69% (n = 117) were male. The typical vasculopath comorbidity profile was noted. Fifty-two percent (n = 88) were referred with claudication-type pain and 25% (n = 43) with critical limb ischaemia (CLI). Twenty-eight percent (n = 33) were active smokers and 31% (n = 36) had no smoking status documented. Regarding BMT, only 34.5% (n = 40) and 52% (n = 60) were on anti-platelets and statins, respectively. Suspected CLI was not significantly associated with BMT prescription at referral (p = 0.664). Only eleven referral letters mentioned risk factor optimisation. CONCLUSIONS: Our first-cycle results identified significant scope for improvement in community-based risk factor modification for PAD referrals. We aim to continue supporting and educating our colleagues that effective medical management can start safely in primary care and further explore the barriers preventing this.

Life history strategies among soil bacteria-dichotomy for few, continuum for many.

Study of life history strategies may help predict the performance of microorganisms in nature by organizing the complexity of microbial communities into groups of organisms with similar strategies. Here, we tested the extent that one common application of life history theory, the copiotroph-oligotroph framework, could predict the relative population growth rate of bacterial taxa in soils from four different ecosystems. We measured the change of in situ relative growth rate to added glucose and ammonium using both 18O-H2O and 13C quantitative stable isotope probing to test whether bacterial taxa sorted into copiotrophic and oligotrophic groups. We saw considerable overlap in nutrient responses across most bacteria regardless of phyla, with many taxa growing slowly and few taxa that grew quickly. To define plausible life history boundaries based on in situ relative growth rates, we applied Gaussian mixture models to organisms' joint 18O-13C signatures and found that across experimental replicates, few taxa could consistently be assigned as copiotrophs, despite their potential for fast growth. When life history classifications were assigned based on average relative growth rate at varying taxonomic levels, finer resolutions (e.g., genus level) were significantly more effective in capturing changes in nutrient response than broad taxonomic resolution (e.g., phylum level). Our results demonstrate the difficulty in generalizing bacterial life history strategies to broad lineages, and even to single organisms across a range of soils and experimental conditions. We conclude that there is a continued need for the direct measurement of microbial communities in soil to advance ecologically realistic frameworks.

Editor's Choice - Systematic Review and Meta-Analysis of Lower Extremity Vascular Complications after Arterial Access for Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA): An Inevitable Concern?

OBJECTIVE: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is used to temporise non-compressible torso haemorrhage. Recent data have suggested that vascular access complications secondary to REBOA placement are higher than initially anticipated. This updated systematic review and meta-analysis aimed to determine the pooled incidence rate of lower extremity arterial complications after REBOA. DATA SOURCES: PubMed, Scopus, Embase, conference abstract listings, and clinical trial registries. REVIEW METHODS: Studies including more than five adults undergoing emergency REBOA for exsanguinating haemorrhage that reported access site complications were eligible for inclusion. A pooled meta-analysis of vascular complications was performed using the DerSimonian-Laird weights for the random effects model, presented as a Forest plot. Further meta-analyses compared the relative risk of access complications between different sheath sizes, percutaneous access techniques, and indications for REBOA. Risk of bias was assessed using the Methodological Index for Non-Randomised Studies (MINORS) tool. RESULTS: No randomised controlled trials were identified, and the overall study quality was poor. Twenty-eight studies including 887 adults were identified. REBOA was performed for trauma in 713 cases. The pooled proportion rate of vascular access complications was 8.6% (95% confidence interval 4.97 - 12.97), with substantial heterogeneity (I2 = 67.6%). There was no significant difference in the relative risk of access complications between 7 and > 10 F sheaths (p = .54), or between ultrasound guided and landmark guided access (p = .081). However, traumatic haemorrhage was associated with a significantly higher risk of complications compared with non-traumatic haemorrhage (p = .034). CONCLUSION: This updated meta-analysis aimed to be as comprehensive as possible considering the poor quality of source data and high risk of bias. It suggested that lower extremity vascular complications were higher than originally suspected after REBOA. While the technical aspects did not appear to impact the safety profile, a cautious association could be drawn between REBOA use for traumatic haemorrhage and a higher risk of arterial complications.

A Report of Penile Mondor's Disease After Mechanochemical Ablation and Adjunct Foam Sclerotherapy of Bilateral Lower Extremity Truncal Incompetence.

INTRODUCTION: Mondor's disease of the penis, or superficial thrombophlebitis affecting penile veins, is a rare condition. Common causes include prothombotic states, venous stasis or excessive manipulation. The literature includes one case report of Mondor's Disease after endovenous laser ablation and foam sclerotherapy and a case series after open saphenofemoral junction ligation. However, there have been no noted cases of this rare complication after mechanochemical ablation of the GSV. CASE DETAILS: A 50-year-old man with bilateral great saphenous venous incompetence had truncal mechanochemical ablation of both above-knee GSV segments with the ClariveinTM device with adjunctive 1% Fibrovein foam to varicose tributaries. Day three post-operatively he began experiencing suprapubic pain and noted tender "cord-like" veins along the penile shaft. Duplex investigation of the penis demonstrated occlusive thrombus in the superficial veins draining into the dorsal vein of the penis. The patient was treated with 75 mg oral Clopidogrel for four weeks and his symptoms resolved without functional impairment. CONCLUSIONS: Vascular surgeons should be aware that this rare albeit self-limiting thrombotic complication can occur after endovenous mechanochemical ablation of the great saphenous vein with adjunct foam sclerotherapy, particularly as this procedure is performed very frequently. Interestingly, the majority of reported cases have occurred after bilateral interventions. The patients can be reassured that their symptoms will likely settle and the use of anti-thrombotic therapy is largely at the surgeon's discretion.

Acute limb ischaemia due to thrombosed persistent sciatic artery aneurysm presents a surgical challenge in a frail octogenarian.

OBJECTIVES: Persistent sciatic artery (PSA) is a rare congenital anomaly, whereby the embryonic sciatic artery remains patent with associated degrees of femoral axis hypoplasia. Aneurysmal degeneration and distal ischaemia from thromboembolic complications are common. Revascularisation strategies include embolectomy, bypass or interposition grafting and catheter-directed thrombolysis. METHODS: We describe a sedentary 88-year-old woman with right acute limb ischaemia secondary to a thrombosed PSA aneurysm and concurrent occlusive thrombus at the femoral bifurcation. RESULTS: The patient presented with a 3-day history of a cold, painful right foot. Examination revealed Rutherford IIb ischaemia. CT-angiography demonstrated no continuity between the hypoplastic superficial femoral and popliteal arteries, complete occlusion of the right PSA distal to the thrombosed aneurysm and occlusive thrombus in the right profunda. As she was too frail for femoral-distal bypass, we restored femoral axis inflow via profunda embolectomy. Her prognosis remained guarded as we deliberately did not reconstruct the PSA. However, she was discharged pain-free and mobilising with aids 2 weeks later. CONCLUSION: Limb ischaemia in frail, high-risk patients is an ever-increasing challenge for vascular surgeons and requires complex decision-making, balancing comorbidities against desired outcomes. This case illustrates that a selective approach can be sufficient to maintain function despite complex anatomy.

A global snapshot of current opinions of next-generation sequencing technologies usage in forensics.

The future of forensic DNA testing is being shaped by the research and usage of next-generation systems, which have increased the multiplexing capabilities of the field and the type and amount of genetic data that can be utilized for investigations. The NGS adoption for casework has been slow, albeit the plethora of data that has been published. This study evaluated the current opinions on sequencing in forensics. A 20-question online-survey focusing on NGS knowledge, training, and usage was distributed to 6001 forensic DNA researchers and practitioners worldwide. A total of 367 responses were obtained from all continents (North/South America (69.8%), Europe (21.2%), Asia (5.5%), Oceania (2.5%), and Africa (1%)). The respondents consisted of 50% practitioners, 31% researchers, and 19% both. Of these, 38% already own a next-gen sequencing instrument, and 13% are planning to purchase one. Overall, there exists an extensive knowledge on next-gen sequencing within the forensic community, including among laboratories that have not yet implemented this high-throughput technology in their workflows. Current usage focuses primarily on SNP analysis for investigative leads and mitochondrial DNA analysis while future applications included both STR and SNP testing applied to general casework. The major overall concerns respondents have for implementing a sequencing instrument include limited funding, staffing, lack of time, and the cost-effectiveness of providing this service. Specific technical concerns that the respondents had are the lack of training, statistical applications, bioinformatics support, and of rigorous guidelines and recommendations. Most of the respondents do believe there will be a technology shift from using CE only to the use of NGS on casework in 5-10 years. In addition, around 66% of respondents believe that it is moderately to very likely that the court will accept sequencing analysis. Sixteen percent fell in the middle, and the remaining 15% believe it is more unlikely, with 3% of respondents believing it is very unlikely. In conclusion, this work outlines current analytical challenges experienced by the global forensic DNA community and addresses different strategies for the implementation of next-gen sequencing technologies in casework.

Quantitative Stable-Isotope Probing (qSIP) with Metagenomics Links Microbial Physiology and Activity to Soil Moisture in Mediterranean-Climate Grassland Ecosystems.

The growth and physiology of soil microorganisms, which play vital roles in biogeochemical cycling, are shaped by both current and historical soil environmental conditions. Here, we developed and applied a genome-resolved metagenomic implementation of quantitative stable isotope probing (qSIP) with an H218O labeling experiment to identify actively growing soil microorganisms and their genomic capacities. qSIP enabled measurement of taxon-specific growth because isotopic incorporation into microbial DNA requires production of new genome copies. We studied three Mediterranean grassland soils across a rainfall gradient to evaluate the hypothesis that historic precipitation levels are an important factor controlling trait selection. We used qSIP-informed genome-resolved metagenomics to resolve the active subset of soil community members and identify their characteristic ecophysiological traits. Higher year-round precipitation levels correlated with higher activity and growth rates of flagellar motile microorganisms. In addition to heavily isotopically labeled bacteria, we identified abundant isotope-labeled phages, suggesting phage-induced cell lysis likely contributed to necromass production at all three sites. Further, there was a positive correlation between phage activity and the activity of putative phage hosts. Contrary to our expectations, the capacity to decompose the diverse complex carbohydrates common in soil organic matter or oxidize methanol and carbon monoxide were broadly distributed across active and inactive bacteria in all three soils, implying that these traits are not highly selected for by historical precipitation. IMPORTANCE Soil moisture is a critical factor that strongly shapes the lifestyle of soil organisms by changing access to nutrients, controlling oxygen diffusion, and regulating the potential for mobility. We identified active microorganisms in three grassland soils with similar mineral contexts, yet different historic rainfall inputs, by adding water labeled with a stable isotope and tracking that isotope in DNA of growing microbes. By examining the genomes of active and inactive microorganisms, we identified functions that are enriched in growing organisms, and showed that different functions were selected for in different soils. Wetter soil had higher activity of motile organisms, but activity of pathways for degradation of soil organic carbon compounds, including simple carbon substrates, were comparable for all three soils. We identified many labeled, and thus active bacteriophages (viruses that infect bacteria), implying that the cells they killed contributed to soil organic matter. The activity of these bacteriophages was significantly correlated with activity of their hosts.

Outcomes of the Macroscopically Normal Appendix Left in Situ in Patients with Suspected Appendicitis.

BACKGROUND: Right iliac fossa (RIF) pain is a common indication for laparoscopy to diagnose and treat appendicitis. When a macroscopically normal appendix is found, there is no standard consensus regarding excision. Some surgeons remove the appendix due to the risk of microscopic inflammation and to avoid a future, repeat laparoscopy for possible appendicitis. Alternatively, others leave the appendix in situ to avoid morbidity from a potentially unnecessary procedure. We aimed to evaluate the outcomes of patients with macroscopically normal appendices left in situ. METHODS: All emergency laparoscopies without appendicectomy between January 1st 2010- December 31st 2020 were identified from theatre records. All operative notes were individually evaluated and comments on the macroscopic appearance of the appendix and any intra-operative pathology were recorded. Only patients undergoing laparoscopy for suspected appendicitis with macroscopically normal appendices were included. RESULTS: A total of 120 patients [median age 21.68 (range 9-90.8) years] were included. The cohort was predominantly female (n=105, 87.5%). Forty-eight patients (40.0%) had a positive finding during index laparoscopy. During a median duration of 94.5 (range 8-131) months' follow-up, 16 patients (13.33%) underwent a repeat laparoscopy for recurrent RIF pain. Thirteen (10.8% of total cohort) subsequently underwent an appendicectomy. Histology confirmed acute appendicitis in six cases (4.17% of entire cohort). On subanalysis of smaller cohort, index laparoscopies with no positive findings (n=72), nine patients (12.5%) underwent appendicectomy with two (2.7%) appendices demonstrating appendicitis on histological examination. CONCLUSION: 87% of the total cohort with a normal appendix at laparoscopy for RIF pain did not undergo further laparoscopy. Less than 5% of the total cohort and 2.7% of subanalysis cohort had an appendicectomy for histologically-proven appendicitis within the follow-up period. From the evidence in this study, we conclude that leaving the appendix in situ unless macroscopically inflamed is a viable alternative to excision.

Life and death in the soil microbiome: how ecological processes influence biogeochemistry.

Soil microorganisms shape global element cycles in life and death. Living soil microorganisms are a major engine of terrestrial biogeochemistry, driving the turnover of soil organic matter - Earth's largest terrestrial carbon pool and the primary source of plant nutrients. Their metabolic functions are influenced by ecological interactions with other soil microbial populations, soil fauna and plants, and the surrounding soil environment. Remnants of dead microbial cells serve as fuel for these biogeochemical engines because their chemical constituents persist as soil organic matter. This non-living microbial biomass accretes over time in soil, forming one of the largest pools of organic matter on the planet. In this Review, we discuss how the biogeochemical cycling of organic matter depends on both living and dead soil microorganisms, their functional traits, and their interactions with the soil matrix and other organisms. With recent omics advances, many of the traits that frame microbial population dynamics and their ecophysiological adaptations can be deciphered directly from assembled genomes or patterns of gene or protein expression. Thus, it is now possible to leverage a trait-based understanding of microbial life and death within improved biogeochemical models and to better predict ecosystem functioning under new climate regimes.