Lecanemab in Early Alzheimer's Disease.

BACKGROUND: The accumulation of soluble and insoluble aggregated amyloid-beta (Aß) may initiate or potentiate pathologic processes in Alzheimer's disease. Lecanemab, a humanized IgG1 monoclonal antibody that binds with high affinity to Aß soluble protofibrils, is being tested in persons with early Alzheimer's disease. METHODS: We conducted an 18-month, multicenter, double-blind, phase 3 trial involving persons 50 to 90 years of age with early Alzheimer's disease (mild cognitive impairment or mild dementia due to Alzheimer's disease) with evidence of amyloid on positron-emission tomography (PET) or by cerebrospinal fluid testing. Participants were randomly assigned in a 1:1 ratio to receive intravenous lecanemab (10 mg per kilogram of body weight every 2 weeks) or placebo. The primary end point was the change from baseline at 18 months in the score on the Clinical Dementia Rating-Sum of Boxes (CDR-SB; range, 0 to 18, with higher scores indicating greater impairment). Key secondary end points were the change in amyloid burden on PET, the score on the 14-item cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-cog14; range, 0 to 90; higher scores indicate greater impairment), the Alzheimer's Disease Composite Score (ADCOMS; range, 0 to 1.97; higher scores indicate greater impairment), and the score on the Alzheimer's Disease Cooperative Study-Activities of Daily Living Scale for Mild Cognitive Impairment (ADCS-MCI-ADL; range, 0 to 53; lower scores indicate greater impairment). RESULTS: A total of 1795 participants were enrolled, with 898 assigned to receive lecanemab and 897 to receive placebo. The mean CDR-SB score at baseline was approximately 3.2 in both groups. The adjusted least-squares mean change from baseline at 18 months was 1.21 with lecanemab and 1.66 with placebo (difference, -0.45; 95% confidence interval [CI], -0.67 to -0.23; P<0.001). In a substudy involving 698 participants, there were greater reductions in brain amyloid burden with lecanemab than with placebo (difference, -59.1 centiloids; 95% CI, -62.6 to -55.6). Other mean differences between the two groups in the change from baseline favoring lecanemab were as follows: for the ADAS-cog14 score, -1.44 (95% CI, -2.27 to -0.61; P<0.001); for the ADCOMS, -0.050 (95% CI, -0.074 to -0.027; P<0.001); and for the ADCS-MCI-ADL score, 2.0 (95% CI, 1.2 to 2.8; P<0.001). Lecanemab resulted in infusion-related reactions in 26.4% of the participants and amyloid-related imaging abnormalities with edema or effusions in 12.6%. CONCLUSIONS: Lecanemab reduced markers of amyloid in early Alzheimer's disease and resulted in moderately less decline on measures of cognition and function than placebo at 18 months but was associated with adverse events. Longer trials are warranted to determine the efficacy and safety of lecanemab in early Alzheimer's disease. (Funded by Eisai and Biogen; Clarity AD ClinicalTrials.gov number, NCT03887455.).

Two Phase 3 Trials of Gantenerumab in Early Alzheimer's Disease.

BACKGROUND: Monoclonal antibodies that target amyloid-beta (Aß) have the potential to slow cognitive and functional decline in persons with early Alzheimer's disease. Gantenerumab is a subcutaneously administered, fully human, anti-Aß IgG1 monoclonal antibody with highest affinity for aggregated Aß that has been tested for the treatment of Alzheimer's disease. METHODS: We conducted two phase 3 trials (GRADUATE I and II) involving participants 50 to 90 years of age with mild cognitive impairment or mild dementia due to Alzheimer's disease and evidence of amyloid plaques on positron-emission tomography (PET) or cerebrospinal fluid (CSF) testing. Participants were randomly assigned to receive gantenerumab or placebo every 2 weeks. The primary outcome was the change from baseline in the score on the Clinical Dementia Rating scale-Sum of Boxes (CDR-SB; range, 0 to 18, with higher scores indicating greater cognitive impairment) at week 116. RESULTS: A total of 985 and 980 participants were enrolled in the GRADUATE I and II trials, respectively. The baseline CDR-SB score was 3.7 in the GRADUATE I trial and 3.6 in the GRADUATE II trial. The change from baseline in the CDR-SB score at week 116 was 3.35 with gantenerumab and 3.65 with placebo in the GRADUATE I trial (difference, -0.31; 95% confidence interval [CI], -0.66 to 0.05; P = 0.10) and was 2.82 with gantenerumab and 3.01 with placebo in the GRADUATE II trial (difference, -0.19; 95% CI, -0.55 to 0.17; P = 0.30). At week 116, the difference in the amyloid level on PET between the gantenerumab group and the placebo group was -66.44 and -56.46 centiloids in the GRADUATE I and II trials, respectively, and amyloid-negative status was attained in 28.0% and 26.8% of the participants receiving gantenerumab in the two trials. Across both trials, participants receiving gantenerumab had lower CSF levels of phosphorylated tau 181 and higher levels of Aß42 than those receiving placebo; the accumulation of aggregated tau on PET was similar in the two groups. Amyloid-related imaging abnormalities with edema (ARIA-E) occurred in 24.9% of the participants receiving gantenerumab, and symptomatic ARIA-E occurred in 5.0%. CONCLUSIONS: Among persons with early Alzheimer's disease, the use of gantenerumab led to a lower amyloid plaque burden than placebo at 116 weeks but was not associated with slower clinical decline. (Funded by F. Hoffmann-La Roche; GRADUATE I and II ClinicalTrials.gov numbers, NCT03444870 and NCT03443973, respectively.).

Familiarity enhances functional connectivity between visual and nonvisual regions of the brain during natural viewing.

We explored the neural correlates of familiarity with people and places using a naturalistic viewing paradigm. Neural responses were measured using functional magnetic resonance imaging, while participants viewed a movie taken from Game of Thrones. We compared inter-subject correlations and functional connectivity in participants who were either familiar or unfamiliar with the TV series. Higher inter-subject correlations were found between familiar participants in regions, beyond the visual brain, that are typically associated with the processing of semantic, episodic, and affective information. However, familiarity also increased functional connectivity between face and scene regions in the visual brain and the nonvisual regions of the familiarity network. To determine whether these regions play an important role in face recognition, we measured responses in participants with developmental prosopagnosia (DP). Consistent with a deficit in face recognition, the effect of familiarity was significantly attenuated across the familiarity network in DP. The effect of familiarity on functional connectivity between face regions and the familiarity network was also attenuated in DP. These results show that the neural response to familiarity involves an extended network of brain regions and that functional connectivity between visual and nonvisual regions of the brain plays an important role in the recognition of people and places during natural viewing.

Quantifying Perioperative Risks for Antireflux and Hiatus Hernia Surgery: A Multicenter Cohort Study of 4301 Patients.

OBJECTIVE: Using a comprehensive Australian cohort, we quantified the incidence and determined the independent predictors of intraoperative and postoperative complications associated with antireflux and hiatus hernia surgeries. In addition, we performed an in-depth analysis to understand the complication profiles associated with each independent risk factor. BACKGROUND: Predicting perioperative risks for fundoplication and hiatus hernia repair will inform treatment decision-making, hospital resource allocation, and benchmarking. However, available risk calculators do not account for hernia anatomy or technical aspects of surgery in estimating perioperative risk. METHODS: Retrospective analysis of all elective antireflux and hiatus hernia surgeries in 36 Australian hospitals over 10 years. Hierarchical multivariate logistic regression analyses were performed to determine the independent predictors of intraoperative and postoperative complications accounting for patient, surgical, anatomic, and perioperative factors. RESULTS: A total of 4301 surgeries were analyzed. Of these, 1569 (36.5%) were large/giant hernias and 292 (6.8%) were revisional procedures. The incidence rates of intraoperative and postoperative complications were 12.6% and 13.3%, respectively. The Charlson Comorbidity Index, hernia size, revisional surgery, and baseline anticoagulant usage independently predicted both intraoperative and postoperative complications. These risk factors were associated with their own complication profiles. Finally, using risk matrices, we visualized the cumulative impact of these 4 risk factors on the development of intraoperative, overall postoperative, and major postoperative complications. CONCLUSIONS: This study has improved our understanding of perioperative morbidity associated with antireflux and hiatus hernia surgery. Our findings group patients along a spectrum of perioperative risks that inform care at an individual and institutional level.

Mapping the functional and structural connectivity of the scene network.

The recognition and perception of places has been linked to a network of scene-selective regions in the human brain. While previous studies have focussed on functional connectivity between scene-selective regions themselves, less is known about their connectivity with other cortical and subcortical regions in the brain. Here, we determine the functional and structural connectivity profile of the scene network. We used fMRI to examine functional connectivity between scene regions and across the whole brain during rest and movie-watching. Connectivity within the scene network revealed a bias between posterior and anterior scene regions implicated in perceptual and mnemonic aspects of scene perception respectively. Differences between posterior and anterior scene regions were also evident in the connectivity with cortical and subcortical regions across the brain. For example, the Occipital Place Area (OPA) and posterior Parahippocampal Place Area (PPA) showed greater connectivity with visual and dorsal attention networks, while anterior PPA and Retrosplenial Complex showed preferential connectivity with default mode and frontoparietal control networks and the hippocampus. We further measured the structural connectivity of the scene network using diffusion tractography. This indicated both similarities and differences with the functional connectivity, highlighting biases between posterior and anterior regions, but also between ventral and dorsal scene regions. Finally, we quantified the structural connectivity between the scene network and major white matter tracts throughout the brain. These findings provide a map of the functional and structural connectivity of scene-selective regions to each other and the rest of the brain.

iCare - a self-directed, interactive online program to improve health and wellbeing for people living with upper gastrointestinal or hepato-pancreato-biliary cancers, and their informal carers: the study protocol for a Phase II randomised controlled trial.

BACKGROUND: Up to 70% of people diagnosed with upper gastrointestinal (GI) tract or hepato-pancreato-biliary (HPB) cancers experience substantial reductions in quality of life (QoL), including high distress levels, pain, fatigue, sleep disturbances, weight loss and difficulty swallowing. With few advocacy groups and support systems for adults with upper GI or HPB cancers (i.e. pancreas, liver, stomach, bile duct and oesophageal) and their carers, online supportive care programs may represent an alternate cost-effective mechanism to support this patient group and carers. iCare is a self-directed, interactive, online program that provides information, resources, and psychological packages to patients and their carers from the treatment phase of their condition. The inception and development of iCare has been driven by consumers, advocacy groups, government and health professionals. The aims of this study are to determine the feasibility and acceptability of iCare, examine preliminary efficacy on health-related QoL and carer burden at 3- and 6-months post enrolment, and the potential cost-effectiveness of iCare, from health and societal perspectives, for both patients and carers. METHODS AND ANALYSIS: A Phase II randomised controlled trial. Overall, 162 people with newly diagnosed upper GI or HPB cancers and 162 carers will be recruited via the Upper GI Cancer Registry, online advertisements, or hospital clinics. Patients and carers will be randomly allocated (1:1) to the iCare program or usual care. Participant assessments will be at enrolment, 3- and 6-months later. The primary outcomes are i) feasibility, measured by eligibility, recruitment, response and attrition rates, and ii) acceptability, measured by engagement with iCare (frequency of logins, time spent using iCare, and use of features over the intervention period). Secondary outcomes are patient changes in QoL and unmet needs, and carer burden, unmet needs and QoL. Linear mixed models will be fitted to obtain preliminary estimates of efficacy and variability for secondary outcomes. The economic analysis will include a cost-consequences analysis where all outcomes will be compared with costs. DISCUSSION: iCare provides a potential model of supportive care to improve QoL, unmet needs and burden of disease among people living with upper GI or HPB cancers and their carers. AUSTRALIAN AND NEW ZEALAND CLINICAL TRIALS REGISTRY: ACTRN12623001185651. This protocol reflects Version #1 26 April 2023.

Developmental pathway for first onset of depressive disorders in females: from adolescence to emerging adulthood.

BACKGROUND: Although risk markers for depressive disorders (DD) are dynamic, especially during adolescence, few studies have examined how change in risk levels during adolescence predict DD onset during transition to adulthood. We compared two competing hypotheses of the dynamic effects of risk. The risk escalation hypothesis posits that worsening of risk predicts DD onset beyond risk level. The chronic risk hypothesis posits that persistently elevated risk level, rather than risk change, predicts DD onset. METHODS: Our sample included 393 girls (baseline age 13.5-15.5 years) from the adolescent development of emotions and personality traits project. Participants underwent five diagnostic interviews and assessments of risk markers for DD at 9-month intervals and were re-interviewed at a 6-year follow-up. We focused on 17 well-established risk markers. For each risk marker, we examined the prospective effects of risk level and change on first DD onset at wave six, estimated by growth curve modeling using data from the first five waves. RESULTS: For 13 of the 17 depression risk markers, elevated levels of risk during adolescence, but not change in risk, predicted first DD onset during transition to adulthood, supporting the chronic risk hypothesis. Minimal evidence was found for the risk escalation hypothesis. CONCLUSIONS: Participants who had a first DD onset during transition to adulthood have exhibited elevated levels of risk throughout adolescence. Researchers and practitioners should administer multiple assessments and focus on persistently elevated levels of risk to identify individuals who are most likely to develop DD and to provide targeted DD prevention.

Lessons from a population-based bladder cancer registry: exploring why survival is not improving.

OBJECTIVE: To explore the causes of the decrease in bladder cancer survival that has occurred over the past four decades. METHODS: We extracted data from the South Australian Cancer Registry. Data from the period 1 January 1977 to 31 December 2020 were extracted to explore changes in incidence and survival among a total of 8356 patients diagnosed with ≥pT1 disease. Invasive bladder cancer was defined as ≥pT1 in this study. RESULTS: Invasive bladder cancer age-standardized incidence decreased from 7.20 cases per 100 000 people in 1977 to 5.85 cases per 100 000 in 2020. The mean age at diagnosis increased from 68 years to 76 years. The crude incidence for patients aged 80 years and over increased by 3.3% per year (95% confidence interval [CI] 2.1 to 4.6). Overall survival decreased over the study period (hazard ratio [HR] 1.22 [95% CI 1.09 to 1.35]), however, survival increased after adjusting for age at diagnosis (HR 0.80 [95% CI 0.76 to 0.94]). Despite a decrease in non-bladder cancer-specific deaths in older people, there was no change in the bladder cancer-specific death rate in older people (HR 0.94 [95% CI 0.70 to 1.26]). Male sex was associated with higher survival (HR 0.87 [95% CI 0.83 to 0.92]), whereas socioeconomic advantage was not. CONCLUSIONS: Invasive bladder cancer survival has decreased over the past 40 years, with the age structure of the population being a significant contributing factor. PATIENT SUMMARY: We looked at why bladder cancer survival is decreasing using a large cancer registry with information from 1977 to 2020. We found that people are now more likely to be diagnosed at an older age. Older people often live for a shorter time with bladder cancer compared to younger people. Bladder cancer survival has decreased because there are more older people with the disease than previously.

Assessment of laparoscopic fundoplication with endoscopy: room for improvement.

INTRODUCTION: Gastroesophageal reflux disease affects a significant portion of the Australian and world population. Minimally invasive laparoscopic fundoplication is a highly effective treatment in appropriately selected patients, with a 90% satisfaction rate. However, up to 5% will undergo revisional surgery. Endoscopy is an important investigation in the evaluation of persistent or new symptoms after fundoplication. Our study sought to evaluate the inter-rater reliability and variability in assessing fundoplication with endoscopy. METHODS: Upper gastrointestinal (UGI) surgeons and gastroenterologists were invited to join the cohort study through their professional membership with two societies based in Australia. Participants completed a two part 25-item multiple choice questionnaire, involving the analysis of ten static endoscopic images post-fundoplication. RESULTS: A total of 101 participants were included in the study (64 UGI surgeons and 37 gastroenterologists). Over 95% of participants were consultant level, working in non-rural tertiary hospitals. Total accuracy for all 10 cases combined was 76% for UGI surgeons and 69.9% for gastroenterologists. In three of the 10 cases, UGI surgeons performed significantly better than gastroenterologists (p < 0.05). When assessing performance across each of the 4 questions for each case, UGI surgeons were more accurate than gastroenterologists in describing the integrity of the wrap (p = 0.014). Inter-rater reliability was low across both groups for most domains (kappa < 1). CONCLUSION: Our study confirms low inter-rater reliability between endoscopists and large variations in reporting. UGI surgeons performed better than gastroenterologists in certain cases, usually when describing the integrity of the fundoplication. Our study provides further support for the use of a standardized reporting system in post-fundoplication patients.

Quality of life following repair of large hiatal hernia is not influenced by the use of mesh-Longer-term follow-up from a randomized trial.

INTRODUCTION: The use of prosthetic mesh in laparoscopic repair of large hiatus hernias remains controversial. Clinical and quality of life outcomes from a randomized controlled trial of mesh versus suture repair previously showed few differences at early follow-up. This study evaluated longer-term quality of life outcomes from that trial. METHODS: A prospective, multicentre, double blind randomized controlled trial assessed three methods of repair for large hiatus hernias: sutures-only versus absorbable mesh versus non-absorbable mesh. Quality of life was assessed using the Short-Form 36 (SF-36) questionnaire which was completed preoperatively and then at 3, 6, 12 months following surgery and annually thereafter. SF-36 outcomes were compared across the three repair techniques at longer-term follow-up (3-6 years), and to earlier baseline and 12-month outcomes. RESULTS: 126 patients were randomized; 43-suture-only, 41-absorbable mesh and 42-non-absorbable mesh. Questionnaires were completed by 118 patients preoperatively, 115 at 12 months and 98 at longer-term follow-up (median 5 years). There were no significant differences between the repair techniques for the subscale and composite scores at longer-term follow-up. The mental component score improved significantly after surgery and was sustained across follow-up for all techniques. The physical component score also improved significantly but was lower at longer-term follow-up compared to the 12-month follow up in both mesh groups. CONCLUSION: Surgical repair of large hiatus hernias provides sustained long-term improvement in quality of life. The addition of mesh does not improve quality of life. TRIAL REGISTRATION: This trial is registered with the Australia and New Zealand Clinical Trials Registry ACTRN12605000725662.

Interface-modulated kinetic differentials in electron and hole transfer rates as a key design principle for redox photocatalysis by Sb2VO5/QD heterostructures.

The efficient conversion of solar energy to chemical energy represents a critical bottleneck to the energy transition. Photocatalytic splitting of water to generate solar fuels is a promising solution. Semiconductor quantum dots (QDs) are prime candidates for light-harvesting components of photocatalytic heterostructures, given their size-dependent photophysical properties and band-edge energies. A promising series of heterostructured photocatalysts interface QDs with transition-metal oxides which embed midgap electronic states derived from the stereochemically active electron lone pairs of p-block cations. Here, we examine the thermodynamic driving forces and dynamics of charge separation in Sb2VO5/CdSe QD heterostructures, wherein a high density of Sb 5s2-derived midgap states are prospective acceptors for photogenerated holes. Hard-x-ray valence band photoemission spectroscopy measurements of Sb2VO5/CdSe QD heterostructures were used to deduce thermodynamic driving forces for charge separation. Interfacial charge transfer dynamics in the heterostructures were examined as a function of the mode of interfacial connectivity, contrasting heterostructures with direct interfaces assembled by successive ion layer adsorption and reaction (SILAR) and interfaces comprising molecular bridges assembled by linker-assisted assembly (LAA). Transient absorption spectroscopy measurements indicate ultrafast (<2 ps) electron and hole transfer in SILAR-derived heterostructures, whereas LAA-derived heterostructures show orders of magnitude differentials in the kinetics of hole (<100 ps) and electron (∼1 ns) transfer. The interface-modulated kinetic differentials in electron and hole transfer rates underpin the more effective charge separation, reduced charge recombination, and greater photocatalytic efficiency observed for the LAA-derived Sb2VO5/CdSe QD heterostructures.

Mucosal impedance as a diagnostic tool for gastroesophageal reflux disease: an update for clinicians.

Mucosal impedance is a marker of esophageal mucosal integrity and a novel technique for assessing esophageal function and pathology. This article highlights its development and clinical application for gastroesophageal reflux disease (GERD), Barrett's esophagus, and eosinophilic esophagitis. A narrative review of key publications describing the development and use of mucosal impedance in clinical practice was conducted. A low mean nocturnal baseline impedance (MNBI) has been shown to be an independent predictor of response to anti-reflux therapy. MNBI predicts medication-responsive heartburn better than distal esophageal acid exposure time. Patients with equivocal evidence of GERD using conventional methods, with a low MNBI, had an improvement in symptoms following the initiation of PPI therapy compared to those with a normal MNBI. A similar trend was seen in a post fundoplication cohort. Strong clinical utility for the use of mucosal impedance in assessing eosinophilic esophagitis has been repeatedly demonstrated; however, there is minimal direction for application in Barrett's esophagus. The authors conclude that mucosal impedance has potential clinical utility for the assessment and diagnosis of GERD, particularly when conventional investigations have yielded equivocal results.

Dopaminergic neuromodulation of prefrontal cortex activity requires the NMDA receptor coagonist d-serine.

Prefrontal control of cognitive functions critically depends upon glutamatergic transmission and N-methyl D-aspartate (NMDA) receptors, the activity of which is regulated by dopamine. Yet whether the NMDA receptor coagonist d-serine is implicated in the dopamine-glutamate dialogue in the prefrontal cortex (PFC) and other brain areas remains unexplored. Here, using electrophysiological recordings, we show that d-serine is required for the fine-tuning of glutamatergic neurotransmission, neuronal excitability, and synaptic plasticity in the PFC through the actions of dopamine at D1 and D3 receptors. Using in vivo microdialysis, we show that D1 and D3 receptors exert a respective facilitatory and inhibitory influence on extracellular levels and activity of d-serine in the PFC, with actions expressed primarily via the cAMP/protein kinase A (PKA) signaling cascade. Further, using functional magnetic resonance imaging (fMRI) and behavioral assessment, we show that d-serine is required for the potentiation of cognition by D3R blockade as revealed in a test of novel object recognition memory. Collectively, these results unveil a key role for d-serine in the dopaminergic neuromodulation of glutamatergic transmission and PFC activity, findings with clear relevance to the pathogenesis and treatment of diverse brain disorders involving alterations in dopamine-glutamate cross-talk.

Dexmedetomidine Utilization During Air Medical Transport for Agitated Patients.

Fixed Wing Air Ambulance providers routinely transport patients agitated from traumatic brain injury sequelae across long distances in a unique environment. The current paradigm limits options available to air medical clinicians to those routinely found on ground based, short distance vehicles, plus whatever a sending facility might be willing to provide. We postulate that dexmedetomidine offers a safe, effective alternative to improve patient care and enhance the safe operation of aircraft.

The effect of mephedrone on human neuroblastoma and astrocytoma cells.

Mephedrone is an illegal drug that is used recreationally. Few studies have been conducted to investigate the mechanisms by which mephedrone is harming cells. In this research, we investigated the effect of mephedrone using toxicology coupled with LC-MS/MS based metabolomics in the two CNS derived cell lines. Methods of assessment such as neutral red (NR) assay, dimethylthiazolyl diphenyltetrazolium bromide (MTT), lactose dehydrogenase (LDH) measurement, and morphology were performed to identify the effect on cell viability and to identify the best concentration to be used in a metabolomics study. A concentration of 100 µM of mephedrone was used in the metabolomic experiment because at this concentration mephedrone had induced several intracellular changes. Although there no clear indicators of cellular damage caused by mephedrone. In astrocytes there was a clear indication that cell membrane function might be impaired by depletion of ether lipids.

Connectopic mapping techniques do not reflect functional gradients in the brain.

Functional gradients, in which response properties change gradually across a brain region, have been proposed as a key organising principle of the brain. Recent studies using both resting-state and natural viewing paradigms have indicated that these gradients may be reconstructed from functional connectivity patterns via "connectopic mapping" analyses. However, local connectivity patterns may be confounded by spatial autocorrelations artificially introduced during data analysis, for instance by spatial smoothing or interpolation between coordinate spaces. Here, we investigate whether such confounds can produce illusory connectopic gradients. We generated datasets comprising random white noise in subjects' functional volume spaces, then optionally applied spatial smoothing and/or interpolated the data to a different volume or surface space. Both smoothing and interpolation induced spatial autocorrelations sufficient for connectopic mapping to produce both volume- and surface-based local gradients in numerous brain regions. Furthermore, these gradients appeared highly similar to those obtained from real natural viewing data, although gradients generated from real and random data were statistically different in certain scenarios. We also reconstructed global gradients across the whole-brain - while these appeared less susceptible to artificial spatial autocorrelations, the ability to reproduce previously reported gradients was closely linked to specific features of the analysis pipeline. These results indicate that previously reported gradients identified by connectopic mapping techniques may be confounded by artificial spatial autocorrelations introduced during the analysis, and in some cases may reproduce poorly across different analysis pipelines. These findings imply that connectopic gradients need to be interpreted with caution.

A global analysis of avian island diversity-area relationships in the Anthropocene.

Research on island species-area relationships (ISAR) has expanded to incorporate functional (IFDAR) and phylogenetic (IPDAR) diversity. However, relative to the ISAR, we know little about IFDARs and IPDARs, and lack synthetic global analyses of variation in form of these three categories of island diversity-area relationship (IDAR). Here, we undertake the first comparative evaluation of IDARs at the global scale using 51 avian archipelagic data sets representing true and habitat islands. Using null models, we explore how richness-corrected functional and phylogenetic diversity scale with island area. We also provide the largest global assessment of the impacts of species introductions and extinctions on the IDAR. Results show that increasing richness with area is the primary driver of the (non-richness corrected) IPDAR and IFDAR for many data sets. However, for several archipelagos, richness-corrected functional and phylogenetic diversity changes linearly with island area, suggesting that the dominant community assembly processes shift along the island area gradient. We also find that archipelagos with the steepest ISARs exhibit the biggest differences in slope between IDARs, indicating increased functional and phylogenetic redundancy on larger islands in these archipelagos. In several cases introduced species seem to have 're-calibrated' the IDARs such that they resemble the historic period prior to recent extinctions.

Optimal Timing of Perioperative Chemoprophylaxis in Patients With High Thromboembolic Risk Undergoing Major Abdominal Surgery: A Multicenter Cohort Study.

OBJECTIVE: To determine whether early (before skin closure) versus postoperative chemoprophylaxis affects the incidence of venous thromboembolism (VTE) and bleeding following major abdominal surgery, in a high thromboembolic risk population. BACKGROUND: Major abdominal surgery incurs both VTE and bleeding risks. Patients with high preoperative VTE risk derive the most benefit from chemoprophylaxis, but carry an increased risk of bleeding. The optimal window for chemoprophylaxis in the perioperative period, whereby both VTE and bleeding risks are minimized, is unknown. METHODS: Analysis of pooled data from 5 multicenter studies including only high thromboembolic risk (Caprini score >4) patients. Clinical VTE was defined as radiographically proven symptomatic disease <30 days postsurgery. Major bleeding was defined as the need for blood transfusion, reintervention, or >20 g/L fall in hemoglobin. RESULTS: From 5501 cases, chemoprophylaxis was initiated early in 1752 (31.8%) patients and postoperatively in 3749 (68.2%) patients. Baseline characteristics were similar between study groups. The incidence of clinical VTE was not associated with chemoprophylaxis timing [early 0.7% vs. postop 0.7%, odds ratio (OR): 1.11, 95% confidence interval (CI): 0.60-2.15, P =0.730]. Contrastingly, compared with postoperative chemoprophylaxis, early usage increased the risk of all bleeding (5.1% vs. 2.6%, OR: 2.04, 95% CI: 1.52-2.73, P <0.001) major bleeding (3.6% vs. 1.8%, OR: 1.99, 95% CI: 1.40-2.81, P <0.001), and reintervention (2.0% vs. 1.0%, OR: 2.10, 95% CI: 1.32-3.35, P =0.003). Early chemoprophylaxis independently predicted postoperative bleeding (OR: 1.71, 95% CI: 1.25-2.34, P <0.001), but not VTE. CONCLUSIONS: In high VTE risk patients undergoing major abdominal surgery, chemoprophylaxis commenced postoperatively reduces bleeding risk without affecting clinical VTE risk.

The benefits and pitfalls of machine learning for biomarker discovery.

Prospects for the discovery of robust and reproducible biomarkers have improved considerably with the development of sensitive omics platforms that can enable measurement of biological molecules at an unprecedented scale. With technical barriers to success lowering, the challenge is now moving into the analytical domain. Genome-wide discovery presents a problem of scale and multiple testing as standard statistical methods struggle to distinguish signal from noise in increasingly complex biological systems. Machine learning and AI methods are good at finding answers in large datasets, but they have a tendency to overfit solutions. It may be possible to find a local answer or mechanism in a specific patient sample or small group of samples, but this may not generalise to wider patient populations due to the high likelihood of false discovery. The rise of explainable AI offers to improve the opportunity for true discovery by providing explanations for predictions that can be explored mechanistically before proceeding to costly and time-consuming validation studies. This review aims to introduce some of the basic concepts of machine learning and AI for biomarker discovery with a focus on post hoc explanation of predictions. To illustrate this, we consider how explainable AI has already been used successfully, and we explore a case study that applies AI to biomarker discovery in rheumatoid arthritis, demonstrating the accessibility of tools for AI and machine learning. We use this to illustrate and discuss some of the potential challenges and solutions that may enable AI to critically interrogate disease and response mechanisms.

Understanding Potentially Preventable Mortality Following Oesophago-Gastric Cancer Surgery: Analysis of a National Audit of Surgical Mortality.

INTRODUCTION: At a national level, understanding preventable mortality after oesophago-gastric cancer surgery can direct quality-improvement efforts. Accordingly, utilizing the Australian and New Zealand Audit of Surgical Mortality (ANZASM), we aimed to: (1) determine the causes of death following oesophago-gastric cancer resections in Australia, (2) quantify the proportion of potentially preventable deaths, and (3) identify clinical management issues contributing to preventable mortality. METHODS: All in-hospital mortalities following oesophago-gastric cancer surgery from 1 January 2010 to 31 December 2020 were analysed using ANZASM data. Potentially preventable and non-preventable cases were compared. Thematic analysis with a data-driven approach was used to classify clinical management issues. RESULTS: Overall, 636 complications and 123 clinical management issues were identified in 105 mortalities. The most common causes of death were cardio-respiratory in aetiology. Forty-nine (46.7%) deaths were potentially preventable. These cases were characterized by higher rates of sepsis (59.2% vs 33.9%, p = 0.011), multiorgan dysfunction syndrome (40.8% vs 25.0%, p = 0.042), re-operation (63.3% vs 41.1%, p = 0.031) and other complications compared with non-preventable mortality. Potentially preventable mortalities also had more clinical management issues per patient [median (IQR): 2 (1-3) vs 0 (0-1), p < 0.001), which adversely impacted preoperative (30.6% vs 7.1%, p = 0.002), intraoperative (18.4% vs 5.4%, p = 0.037) and postoperative (51.0% vs 17.9%, p < 0.001) care. Thematic analysis highlighted recurrent areas of deficiency with preoperative, intraoperative and postoperative patient management. CONCLUSIONS: Almost 50% of deaths following oesophago-gastric cancer resections were potentially preventable. These were characterized by higher complication rates and clinical management issues. We highlight recurrent themes in patient management to improve future quality of care.