Megafauna assemblages have declined or disappeared throughout much of the world, and many efforts are underway to restore them. Understanding the trophic ecology of such reassembling systems is ...necessary for predicting recovery dynamics, guiding management, and testing general theory. Yet, there are few studies of recovering large‐mammal communities, and fewer still that have characterized food‐web structure with high taxonomic resolution.
In Gorongosa National Park, large herbivores have rebounded from near‐extirpation following the Mozambican Civil War (1977–1992). However, contemporary community structure differs radically from the prewar baseline: medium‐sized ungulates now outnumber larger bodied species, and several apex carnivores remain locally extinct.
We used DNA metabarcoding to quantify diet composition of Gorongosa’s 14 most abundant large‐mammal populations. We tested five hypotheses: (i) the most abundant populations exhibit greatest individual‐level dietary variability; (ii) these populations also have the greatest total niche width (dietary diversity); (iii) interspecific niche overlap is high, with the diets of less‐abundant species nested within those of more‐abundant species; (iv) partitioning of forage species is stronger in more structurally heterogeneous habitats; and (v) selectivity for plant taxa converges within guilds and digestive types, but diverges across them.
Abundant (and narrow‐mouthed) populations exhibited higher among‐individual dietary variation, but not necessarily the greatest dietary diversity. Interspecific dietary overlap was high, especially among grazers and in structurally homogenous habitat, whereas niche separation was more pronounced among browsers and in heterogeneous habitat. Patterns of selectivity were similar for ruminants—grazers and browsers alike—but differed between ruminants and non‐ruminants.
Synthesis. The structure of this recovering food web was consistent with several hypotheses predicated on competition, habitat complexity, and herbivore traits, but it differed from patterns observed in more intact assemblages. We propose that intraspecific competition in the fastest‐recovering populations has promoted individual variation and a more nested food web, wherein rare species use subsets of foods eaten by abundant species, and that this scenario is reinforced by weak predation pressure. Future work should test these conjectures and analyse how the taxonomic dietary niche axis studied here interacts with other mechanisms of diet partitioning to affect community reassembly following wildlife declines.
The structure of this recovering food web was consistent with several hypotheses predicated on competition, habitat complexity, and herbivore traits, but it differed from patterns observed in more intact assemblages. We propose that competition and the extirpation of top predators have promoted individual variation, inter‐specific niche overlap and a more nested food web wherein rare species use subsets of foods eaten by abundant species.
Foreign Language Résumé
Les communautés de grands mammifères ont décliné, voire disparu, en de nombreux endroits du globe, et d’importants efforts sont actuellement en cours pour les restaurer. Comprendre l’écologie trophique de ces espèces dans les écosystèmes en restauration est nécessaire afin d’anticiper leurs dynamiques de rétablissement, d’orienter leur gestion, et de tester la généralité des théories dérivées de systèmes considérés comme préservés. Néanmoins, les études sur le rétablissement des communautés de grands mammifères restent rares à ce jour, et peu d’entre elles ont caractérisé, à haute résolution taxonomique, la structure du réseau trophique.
Dans le Parc National de Gorongosa (Mozambique), les populations de grands herbivores se sont redressées après avoir été quasiment exterminées suite à la guerre civile (1977–1992). Cependant, la structure actuelle de la communauté diffère radicalement de celle observée avant‐guerre: les ongulés de taille moyenne dépassent aujourd’hui en nombre les espèces les plus volumineuses, et de nombreuses espèces de carnivores supérieurs sont toujours localement éteintes.
Dans cette étude, une approche de metabarcoding ADN a été employée sur des échantillons fécaux afin de déterminer la composition taxonomique du régime alimentaire des 14 populations de grands mammifères les plus abondantes. Nous avons ainsi testé cinq hypothèses relatives à leur écologie trophique: (i) la variabilité de la niche alimentaire au niveau individuel est plus importante chez les populations les plus abondantes; (ii) ces dernières ont également une niche trophique plus large au niveau populationnel; (iii) le chevauchement des niches entre espèces est important, et les régimes alimentaires des espèces les plus rares sont imbriqués dans ceux des espèces les plus abondantes; (iv) la ségrégation des niches trophiques est plus importante dans les habitats structurellement plus hétérogènes; (v) la sélectivité des taxons de plantes par les herbivores tend à converger au sein d’une même guilde alimentaire et entre espèces partageant le même type de système digestif, mais divergent entre ces groupes.
Les populations abondantes, et à museau étroit, présentent une variabilité interindividuelle du régime alimentaire plus importante que les autres, mais n’ont pas nécessairement une niche trophique plus large. Le chevauchement des niches trophiques au niveau interspécifique est important, en particulier parmi les paisseurs et dans les habitats structurellement homogènes, alors que la différenciation des niches est plus prononcée chez les brouteurs et dans les habitats hétérogènes. Les différentes espèces de ruminants exhibent des patrons de sélectivité similaires, indépendamment de leur guilde alimentaire, mais ceux‐ci diffèrent entre ruminants et non‐ruminants.
Synthèse. La structure de ce réseau trophique en restauration est cohérente avec plusieurs hypothèses basées sur la compétition, la complexité de l’habitat et les traits des herbivores, mais elle diffère des patrons observés dans les communautés peu ou pas perturbées. Nous proposons ici l’idée que la compétition intraspécifique a favorisé la variabilité interindividuelle du régime alimentaire chez les populations qui se sont rapidement rétablies, et a mené à un réseau trophique plus imbriqué, dans lequel les espèces d’herbivores les plus rares utilisent un sous‐ensemble des ressources mangées par les espèces les plus abondantes; ce scenario étant renforcé par un faible contrôle des populations par les prédateurs. Les travaux à venir devront tester ces conjectures et analyser la manière dont la composante ‘taxonomique’ de la niche trophique, étudiée ici, interagit avec les autres mécanismes de partition des ressources, et affecte le réassemblage des communautés suite au déclin des populations.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Circulating proteins can reveal key pathways to cancer and identify therapeutic targets for cancer prevention. We investigate 2,074 circulating proteins and risk of nine common cancers (bladder, ...breast, endometrium, head and neck, lung, ovary, pancreas, kidney, and malignant non-melanoma) using cis protein Mendelian randomisation and colocalization. We conduct additional analyses to identify adverse side-effects of altering risk proteins and map cancer risk proteins to drug targets. Here we find 40 proteins associated with common cancers, such as PLAUR and risk of breast cancer odds ratio per standard deviation increment: 2.27, 1.88-2.74, and with high-mortality cancers, such as CTRB1 and pancreatic cancer 0.79, 0.73-0.85. We also identify potential adverse effects of protein-altering interventions to reduce cancer risk, such as hypertension. Additionally, we report 18 proteins associated with cancer risk that map to existing drugs and 15 that are not currently under clinical investigation. In sum, we identify protein-cancer links that improve our understanding of cancer aetiology. We also demonstrate that the wider consequence of any protein-altering intervention on well-being and morbidity is required to interpret any utility of proteins as potential future targets for therapeutic prevention.
With the recent addition of airflow and respiratory effort channels, our group has observed central and mixed apnea events during drug-induced sleep endoscopy (DISE). We measured the frequency and ...timing of sentinel central and/or mixed events (SCents), as well as assessed for differences in velum, oropharynx, tongue, and epiglottis (VOTE) classification compared to obstructive events.
Prospective single-cohort study.
Tertiary Care Academic Medical Center.
Patients underwent DISE between June 2020 and November 2022. Nasal airflow, thoracoabdominal effort belt signals, and videoendoscopy were simultaneously captured. Demographics, sleep study, and DISE data were compared among patients with and without SCents using Student's T tests or χ
tests.
On average, the cohort (n = 103) was middle-aged (53.5 ± 12.1 years), overweight (body mass index of 29.7 ± 5.3 kg/m
), and had severe obstructive sleep apnea (apnea-hypopnea index of 30.7 ± 18.7 events/h). Forty-seven patients (46%) were found to have at least 1 SCent. Among those with SCent, 45 (95.7%) transitioned to obstructive pathology after an average of 7.91 ± 2.74 minutes, with at least 95% of patients expected to do so within 12.57 minutes. Twenty-nine out of 47 patients (61.2% 95% confidence interval: 46.4.9%, 75.5%) with SCent had meaningful differences between central/mixed and obstructive VOTE scores.
Central events were present in almost half of our cohort. At least 95% of patients were expected to transition to obstructive events within 12 to 13 minutes of propofol initiation. In addition, over half of patients demonstrate significantly different VOTE scores between central and obstructive events. These factors should raise awareness of central events and scoring passive apneas during DISE and consider delaying VOTE scoring.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Single-pill combination therapy containing four quarter-dose medications for high blood pressure improves BP control compared to monotherapy, however patient-reported acceptance of the quadpill as a ...treatment strategy remains undescribed. We collected within-trial feedback and interviewed participants from the quadruple ultra-low-dose treatment for hypertension (QUARTET) trial to characterise patient attitudes to this intervention. All trial participants were asked about ease and preference for the quadpill and provided an opportunity to give further comments on the trial at 12 weeks (trial primary endpoint) and 52 weeks extended follow-up. Separately, we used purposive and quota sampling for the semi-structured telephone interviews, with the resultant verbatim transcripts analysed using an inductive thematic analysis approach. Themes were re-evaluated after each successive interview, and at suspected data saturation, an additional interview conducted for confirmation. At 12 weeks follow-up, 502 of 591 (85%) participants responded to acceptability questions, and 359 of 417 (86%) responded at week 52. Most reported the trial capsule easy or very easy to take. From eight sites, 16 participants were interviewed between 5 August 2020 and 19 November 2020. All described a positive experience, preferred once-daily morning dosing and found routine facilitated adherence. Participants valued individual responsibility for adherence, and involvement of the general practitioner in blood-pressure management. Most reported capsule size did not deter adherence but desired a smaller capsule. Participants described a preference for minimising number and dosage of medications, reduced capsule size, and once-daily morning dosing. These findings suggest a preference for single-pill combination therapy for blood pressure lowering.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Airway rapid response (ARR) teams can be compiled of anesthesiologists, intensivists, otolaryngologists, general and thoracic surgeons, respiratory therapists, and nurses. The optimal composition of ...an ARR team is unknown but considered to be resource intensive. We sought to determine the type of technical procedures performed during an ARR activation to inform team composition.
A large urban quaternary academic medical center retrospective review (2016-2019) of adult ARR patients was performed. Analysis included ARR demographics, patient characteristics, characteristics of preexisting tracheostomies, incidence of concomitant conditions, and procedures completed during an ARR event.
A total of 345 ARR patients with a median age of 60 years (interquartile range, 47-69 years) and a median time to ARR conclusion of 28 minutes (interquartile range, 14-47 minutes) were included. About 41.7% of the ARR had a preexisting tracheostomy. Overall, there were 130 procedures completed that can be performed by a general surgeon in addition to the 122 difficult intubations. These procedures included recannulation of a tracheostomy, operative intervention, new emergent tracheostomy or cricothyroidotomy, thoracostomy tube placement, initiation of extracorporeal membrane oxygenation, and pericardiocentesis.
Highly technical procedures are common during an ARR, including procedures related to tracheostomies. Surgeons possess a comprehensive skill set that is unique and comprehensive with respect to airway emergencies. This distinctive skill set creates an important role within the ARR team to perform these urgent technical procedures.
Epidemiologic/prognostic, level III.
Introduction
Patients with COVID-19 ARDS require significant amounts of sedation and analgesic medications which can lead to longer hospital/ICU length of stay, delirium, and has been associated with ...increased mortality. Tracheostomy has been shown to decrease the amount of sedative, anxiolytic and analgesic medications given to patients. The goal of this study was to assess whether tracheostomy decreased sedation and analgesic medication usage, improved markers of activity level and cognitive function, and clinical outcomes in patients with COVID-19 ARDS.
Study Design and Methods
A retrospective registry of patients with COVID-19 ARDS who underwent tracheostomy creation at the University of Pennsylvania Health System or the Johns Hopkins Hospital from 3/2020 to 12/2020. Patients were grouped into the early (≤14 days, n = 31) or late (15 + days, n = 97) tracheostomy groups and outcome data collected.
Results
128 patients had tracheostomies performed at a mean of 19.4 days, with 66% performed percutaneously at bedside. Mean hourly dose of fentanyl, midazolam, and propofol were all significantly reduced 48-h after tracheostomy: fentanyl (48-h pre-tracheostomy: 94.0 mcg/h, 48-h post-tracheostomy: 64.9 mcg/h, P = .000), midazolam (1.9 mg/h pre vs. 1.2 mg/h post, P = .0012), and propofol (23.3 mcg/kg/h pre vs. 8.4 mcg/kg/h post, P = .0121). There was a significant improvement in mobility score and Glasgow Coma Scale in the 48-h pre- and post-tracheostomy. Comparing the early and late groups, the mean fentanyl dose in the 48-h pre-tracheostomy was significantly higher in the late group than the early group (116.1 mcg/h vs. 35.6 mcg/h, P = .03). ICU length of stay was also shorter in the early group (37.0 vs. 46.2 days, P = .012).
Interpretation
This data supports a reduction in sedative and analgesic medications administered and improvement in cognitive and physical activity in the 48-h period post-tracheostomy in COVID-19 ARDS. Further, early tracheostomy may lead to significant reductions in intravenous opiate medication administration, and ICU LOS.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Esophageal squamous cell carcinoma (ESCC) shows remarkable variation in incidence that is not fully explained by known lifestyle and environmental risk factors. It has been speculated that an unknown ...exogenous exposure(s) could be responsible. Here we combine the fields of mutational signature analysis with cancer epidemiology to study 552 ESCC genomes from eight countries with varying incidence rates. Mutational profiles were similar across all countries studied. Associations between specific mutational signatures and ESCC risk factors were identified for tobacco, alcohol, opium and germline variants, with modest impacts on mutation burden. We find no evidence of a mutational signature indicative of an exogenous exposure capable of explaining differences in ESCC incidence. Apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like (APOBEC)-associated mutational signatures single-base substitution (SBS)2 and SBS13 were present in 88% and 91% of cases, respectively, and accounted for 25% of the mutation burden on average, indicating that APOBEC activation is a crucial step in ESCC tumor development.
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GEOZS, IJS, IMTLJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZAGLJ
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