Virtual urgent care is here to stay: driving toward safe, equitable, and sustainable integration within emergency medicine

BACKGROUND

Virtual care in Canada rapidly expanded during the COVID-19 pandemic in a low-rules environment in response to pressing needs for ongoing access to care amid public health restrictions. Emergency medicine specialists now face the challenge of advising on which virtual urgent care services ought to remain as part of comprehensive emergency care. Consideration must be given to safe, quality, and appropriate care as well as issues of equitable access, public demand, and sustainability (financial and otherwise). The aim of this project was to summarize current literature and expert opinion and formulate recommendations on the path forward for virtual care in emergency medicine.

METHODS

We formed a working group of emergency medicine physicians from across Canada working in a variety of practice settings. The virtual care working group conducted a scoping review of the literature and met monthly to discuss themes and develop recommendations. The final recommendations were circulated to stakeholders for input and subsequently presented at the 2023 Canadian Association of Emergency Physicians (CAEP) Academic Symposium for discussion, feedback, and refinement.

RESULTS

The working group developed and reached unanimity on nine recommendations addressing the themes of system design, equity and accessibility, quality and patient safety, education and curriculum, financial models, and sustainability of virtual urgent care services in Canada.

CONCLUSION

Virtual urgent care has become an established service in the Canadian health care system. Emergency medicine specialists are uniquely suited to provide leadership and guidance on the optimal delivery of these services to enhance and complement emergency care in Canada.

Molecular determinants and signaling effects of PKA RIα phase separation

Spatiotemporal regulation of intracellular signaling molecules, such as the 3',5'-cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA), ensures proper cellular function. Liquid-liquid phase separation (LLPS) of the ubiquitous PKA regulatory subunit RIα promotes cAMP compartmentation and signaling specificity. However, the molecular determinants of RIα LLPS remain unclear. Here, we reveal that two separate dimerization interfaces, combined with the cAMP-induced unleashing of the PKA catalytic subunit (PKA-C) from the pseudosubstrate inhibitory sequence, drive RIα condensate formation in the cytosol of mammalian cells, which is antagonized by docking to A-kinase anchoring proteins. Strikingly, we find that the RIα pseudosubstrate region is critically involved in forming a non-canonical R:C complex, which recruits active PKA-C to RIα condensates to maintain low basal PKA activity in the cytosol. Our results suggest that RIα LLPS not only facilitates cAMP compartmentation but also spatially restrains active PKA-C, thus highlighting the functional versatility of biomolecular condensates in driving signaling specificity.

Genetically encodable biosensors for Ras activity

Genetically encoded Ras biosensors have been instrumental in illuminating the spatiotemporal dynamics of Ras activity since the beginning of the imaging revolution of the early 21st century. In general, these sensors employ Ras sensing units coupled with fluorescent proteins. These biosensors have not only helped elucidate Ras signalling dynamics at the plasma membrane but also revealed novel roles for Ras signalling within subcellular compartments such as the Golgi apparatus. In this review, we discuss the different classes of biosensors used to measure Ras activity and discuss their importance in uncovering new roles for Ras activity in cellular signalling and behavior.

Sensitive Fluorescent Biosensor Reveals Differential Subcellular Regulation of PKC

The protein kinase C (PKC) family of serine/threonine kinases, which consist of three distinctly regulated subfamilies, have long been established as critical for a variety of cellular functions. However, how PKC enzymes are regulated at different subcellular locations, particularly at emerging signaling hubs such as the ER, lysosome, and Par signaling complexes, is unclear. Here, we present a sensitive Excitation Ratiometric (ExRai) C Kinase Activity Reporter (ExRai-CKAR2) that enables the detection of minute changes in subcellular PKC activity. Using ExRai-CKAR2 in conjunction with an enhanced diacylglycerol (DAG) biosensor capable of detecting intracellular DAG dynamics, we uncover the differential regulation of PKC isoforms at distinct subcellular locations. We find that G-protein coupled receptor (GPCR) stimulation triggers sustained PKC activity at the ER and lysosomes, primarily mediated by Ca2+ sensitive conventional PKC (cPKC) and novel PKC (nPKC), respectively, with nPKC showing high basal activity due to elevated basal DAG levels on lysosome membranes. The high sensitivity of ExRai-CKAR2, targeted to either the cytosol or Par-complexes, further enabled us to detect previously inaccessible endogenous atypical PKC (aPKC) activity in 3D organoids. Taken together, ExRai-CKAR2 is a powerful tool for interrogating PKC regulation in response to physiological stimuli.

Light-gated Integrator for Highlighting Kinase Activity in Living Cells

Protein kinases are key signaling nodes that regulate fundamental biological and disease processes. Illuminating kinase signaling from multiple angles can provide deeper insights into disease mechanisms and improve therapeutic targeting. While fluorescent biosensors are powerful tools for visualizing live-cell kinase activity dynamics in real time, new molecular tools are needed that enable recording of transient signaling activities for post hoc analysis and targeted manipulation. Here, we develop a light-gated kinase activity coupled transcriptional integrator (KINACT) that converts dynamic kinase signals into "permanent" fluorescent marks. KINACT enables robust monitoring of kinase activity across scales, accurately recording subcellular PKA activity, highlighting PKA signaling heterogeneity in 3D cultures, and identifying PKA activators and inhibitors in high-throughput screens. We further leverage the ability of KINACT to drive signaling effector expression to allow feedback manipulation of the balance of GαsR201C-induced PKA and ERK activation and dissect the mechanisms of oncogenic G protein signaling.

Next-Generation Genetically Encoded Fluorescent Biosensors Illuminate Cell Signaling and Metabolism

Genetically encoded fluorescent biosensors have revolutionized the study of cell signaling and metabolism, as they allow for live-cell measurements with high spatiotemporal resolution. This success has spurred the development of tailor-made biosensors that enable the study of dynamic phenomena on different timescales and length scales. In this review, we discuss different approaches to enhancing and developing new biosensors. We summarize the technologies used to gain structural insights into biosensor design and comment on useful screening technologies. Furthermore, we give an overview of different applications where biosensors have led to key advances over recent years. Finally, we give our perspective on where future work is bound to make a large impact. Expected final online publication date for the Annual Review of Biophysics, Volume 53 is May 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Far-red chemigenetic biosensors for multi-dimensional and super-resolved kinase activity imaging

Fluorescent biosensors revolutionized biomedical science by enabling the direct measurement of signaling activities in living cells, yet the current technology is limited in resolution and dimensionality. Here, we introduce highly sensitive chemigenetic kinase activity biosensors that combine the genetically encodable self-labeling protein tag HaloTag7 with bright far-red-emitting synthetic fluorophores. This technology enables five-color biosensor multiplexing, 4D activity imaging, and functional super-resolution imaging via stimulated emission depletion (STED) microscopy.

Molecular Determinants and Signaling Effects of PKA RIα Phase Separation

Spatiotemporal regulation of intracellular signaling molecules, such as the 3',5'-cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA), ensures the specific execution of various cellular functions. Liquid-liquid phase separation (LLPS) of the ubiquitously expressed PKA regulatory subunit RIα was recently identified as a major driver of cAMP compartmentation and signaling specificity. However, the molecular determinants of RIα LLPS remain unclear. Here, we reveal that two separate dimerization interfaces combined with the cAMP-induced release of the PKA catalytic subunit (PKA-C) from the pseudosubstrate inhibitory sequence are required to drive RIα condensate formation in cytosol, which is antagonized by docking to A-kinase anchoring proteins. Strikingly, we find that the RIα pseudosubstrate region is critically involved in the formation of a non-canonical R:C complex, which serves to maintain low basal PKA activity in the cytosol by enabling the recruitment of active PKA-C to RIα condensates. Our results suggest that RIα LLPS not only facilitates cAMP compartmentation but also spatially restrains active PKA-C, thus highlighting the functional versatility of biomolecular condensates in driving signaling specificity.

Gender equity of authorship in pulmonary medicine over the past decade

BACKGROUND

Gender disparity in authorship broadly persists in medical literature, little is known about female authorship within pulmonary medicine.

METHODS

A bibliometric analysis of publications from 2012 to 2021 in 12 journals with the highest impact in pulmonary medicine was conducted. Only original research and review articles were included. Names of the first and last authors were extracted and their genders were identified using the Gender-API web. Female authorship was described by overall distribution and distribution by country/region/continent and journal. We compared the article citations by gender combinations, evaluated the trend in female authorship, and forecasted when parity for first and last authorship would be reached. We also conducted a systematic review of female authorship in clinical medicine.

RESULTS

14,875 articles were included, and the overall percentage of female first authors was higher than last authors (37.0% vs 22.2%, p<0.001). Asia had the lowest percentage of female first (27.6%) and last (15.2%) authors. The percentages of female first and last authors increased slightly over time, except for a rapid increase in the COVID-19 pandemic periods. Parity was predicted in 2046 for the first authors and 2059 for the last authors. Articles with male authors were cited more than articles with female authors. However, male-male collaborations significantly decreased, whereas female-female collaborations significantly increased.

CONCLUSIONS

Despite the slow improvement in female authorship over the past decade, there is still a substantial gender disparity in female first and last authorship in high-impact medical journals in pulmonary medicine.

Fluorescent biosensors illuminate the spatial regulation of cell signaling across scales

As cell signaling research has advanced, it has become clearer that signal transduction has complex spatiotemporal regulation that goes beyond foundational linear transduction models. Several technologies have enabled these discoveries, including fluorescent biosensors designed to report live biochemical signaling events. As genetically encoded and live-cell compatible tools, fluorescent biosensors are well suited to address diverse cell signaling questions across different spatial scales of regulation. In this review, methods of examining spatial signaling regulation and the design of fluorescent biosensors are introduced. Then, recent biosensor developments that illuminate the importance of spatial regulation in cell signaling are highlighted at several scales, including membranes and organelles, molecular assemblies, and cell/tissue heterogeneity. In closing, perspectives on how fluorescent biosensors will continue enhancing cell signaling research are discussed.

Fluorescent biosensor imaging meets deterministic mathematical modelling: quantitative investigation of signalling compartmentalization

Cells execute specific responses to diverse environmental cues by encoding information in distinctly compartmentalized biochemical signalling reactions. Genetically encoded fluorescent biosensors enable the spatial and temporal monitoring of signalling events in live cells. Temporal and spatiotemporal computational models can be used to interpret biosensor experiments in complex biochemical networks and to explore hypotheses that are difficult to test experimentally. In this review, we first provide brief discussions of the experimental toolkit of fluorescent biosensors as well as computational basics with a focus on temporal and spatiotemporal deterministic models. We then describe how we used this combined approach to identify and investigate a protein kinase A (PKA) - cAMP - Ca2+ oscillatory circuit in MIN6 β cells, a mouse pancreatic β cell system. We describe the application of this combined approach to interrogate how this oscillatory circuit is differentially regulated in a nano-compartment formed at the plasma membrane by the scaffolding protein A kinase anchoring protein 79/150. We leveraged both temporal and spatiotemporal deterministic models to identify the key regulators of this oscillatory circuit, which we confirmed with further experiments. The powerful approach of combining live-cell biosensor imaging with quantitative modelling, as discussed here, should find widespread use in the investigation of spatiotemporal regulation of cell signalling.

Radiation Therapy Knowledge and Health Literacy among Culturally Diverse Patients with Prostate Cancer Treated at a Safety-Net Hospital

PURPOSE/OBJECTIVE(S)

Shared decision making is integral to the physician-patient relationship for radiotherapy (RT) patients. It is implicit that patients both comprehend and retain information explained during consultation. However, quality and quantity of patient knowledge following this visit is unknown. The purpose of this study was to evaluate post-consultation RT knowledge and health literacy among a diverse group of patients.

MATERIALS/METHODS

Participants were patients ≥18 years old who received consultation for definitive or salvage RT to the prostate gland/fossa between April 2021 and January 2023 at an urban safety-net hospital. Following consultation, patients completed the Radiation Oncology Knowledge Assessment Survey (ROKAS), designed to measure patient understanding of proposed RT treatment (e.g., treatment frequency, length, safety) and possible short- and long-term side effects (SE). Additional measures included patients' health literacy, health numeracy (numerical medical concepts), acculturation (assimilation to the dominant culture), and socioeconomic factors. ROKAS was administered in both English and Spanish with Spanish-speaking patients offered medical translation if desired. Bivariate Pearson correlations were conducted to examine the relationships between independent variables and post-consultation RT knowledge. Two-sided t-tests were conducted to examine differences in patients' knowledge by language.

RESULTS

Overall, 39 ROKAS were completed by 24 English-speaking and 15 Spanish-speaking patients (mean age 64.4 [SD 6.8], range 52-79). The majority (93%) of patients 'agreed' or 'strongly agreed' that they understood all the RT information presented. However, only 70% of the RT questions were answered correctly with 26% of patients answering all RT questions correctly. Similarly, 95% of patients 'agreed' or 'strongly agreed' with knowing the side effects of their proposed treatment, but only 71% and 74% of short- and long-term SE questions, respectively, were answered correctly. Higher health literacy (p = 0.04) and health numeracy (p = 0.001) were significantly correlated with better understanding of short-term SE, but not with RT knowledge or long-term SE. Spanish-speaking patients had significantly lower scores of health literacy (p = 0.001) and understanding of long-term (p = 0.01), but not short-term SE.

CONCLUSION

There is a significant gap between perceived and measured knowledge of RT treatment and SE in patients who receive consultation for RT to the prostate gland/fossa. Health literacy was significantly associated with improved knowledge of RT and short-term SE. Spanish-speaking patients had poorer understanding of long-term SE than English-speaking patients. Efforts to identify gaps in patient health literacy are needed to target those at risk and ensure that culturally diverse patient populations can engage in shared decision making with their providers.

Contouring Analysis on Synthetic Contrast-Enhanced MR from GRMM-GAN and Implications on MR-Guide Radiation Therapy

PURPOSE/OBJECTIVE(S)

MR-guided linear accelerators have been commercialized making MR-only planning and adaptation an appealing alternative circumventing MR-CT registration. However, obtaining daily contrast-enhanced MR images can be prohibitive due to the increased risk of side effects from repeated contrast injections. In this work, we evaluate the quality of contrast-enhanced multi-modal MR image synthesis network GRMM-GAN (gradient regularized multi-modal multi-discrimination sparse-attention fusion generative adversarial network) for MR-guided radiation therapy.

MATERIALS/METHODS

With IRB approval, we trained the GRMM-GAN based on 165 abdominal MR studies from 65 patients. Each study included T2, T1 pre-contrast (T1pre), and T1 contrast enhanced (T1ce) images. The two pre-contrast MR modalities, T2 and T1pre images were adopted as inputs for GRMM-GAN, and the T1ce image at the portal venous phase was used as an output. Ten MR scans containing 21 liver tumors were selected for contouring analysis. A Turing test was first given to six radiation oncologists, in which 100 real T1ce and synthetic T1ce image slices are randomly given to the radiation oncologists to determine the authenticity of the synthesis. We then invited two radiation oncologists (RadOnc 1 and RadOnc2) to manually contour the 21 liver tumors independently on the real T1ce images. RadOnc2 then performed contouring on the respective synthetic T1ce MRs. DICE coefficient (defined as the intersection over the average of two volumes) and Hausdorff distance (HD, measuring how far two volumes are from each other) were used as analysis metrics. The DICE coefficients were calculated from the two radiation oncologists' contours on the real T1ce MR for each tumor. The DICE coefficients were also calculated from RadOnc 2's contours on real and synthetic MRs. Besides, tumor center shifts were extracted. The tumor center of mass coordinates was extracted from real and synthetic volumes. The difference in the coordinates indicated the shifts in the superior-inferior (SI), right-left (RL), and anterior-posterior (AP) directions between real and synthetic tumor volumes.

RESULTS

An average of 52.3% test score was achieved from the six radiation oncologists, which is close to random guessing. RadOnc 1 and RadOnc 2, who had participated in the contouring analysis, achieved an average DICE of 0.91±0.02 from tumor volumes drawn on the real T1ce MRs. This result sets the inter-operator uncertainty baseline in the real clinical setting. RadOnc 2 achieved an average DICE (real vs. synth) of 0.90±0.04 and HD of 4.76±1.82 mm. Only sub-millimeter (SI: 0.67 mm, RL: 0.41 mm, AP: 0.39 mm) tumor center shifts were observed in all three directions.

CONCLUSION

The GRMM-GAN method has the potential for MR-guided liver radiation when contrast agents cannot be administered daily and provide synthetic contrast-enhanced MR for better tumor targeting. The network can produce synthetic MR images with satisfactory contour agreement and geometric integrity.

A Combined Phase 0/2 "Trigger" Trial Evaluating Pamiparib or Olaparib with Concurrent Radiotherapy in Patients with Newly-Diagnosed or Recurrent Glioblastoma

PURPOSE/OBJECTIVE(S)

This study evaluates the pharmacokinetic (PK) and pharmacodynamic (PD) profiles and clinical efficacy of PARP1/2 selective inhibitors, pamiparib and olaparib, in newly-diagnosed or recurrent glioblastoma (GBM) patients in combination with radiotherapy (RT).

MATERIALS/METHODS

In this combined phase 0/2 trial presumed newly-diagnosed (Arm A) or recurrent (Arm B) GBM patients received 4 days of pamiparib (60 mg BID) prior to resection either 2-4 or 8-12 hours following the final dose. Arm C enrolled patients with recurrent GBM to 4 days of olaparib (200 mg BID) prior to resection. Enhancing and nonenhancing tumor tissue, cerebrospinal fluid (CSF) and plasma were collected. Total and unbound drug concentrations were measured using validated LC-MS/MS methods. A PK 'trigger', defined as unbound drug and gt; 5-fold biochemical IC 50 in nonenhancing tumor, determined eligibility for the therapeutic expansion phase 2. PARP inhibition was assessed via ex vivo radiation and quantification of PAR levels compared to non-radiated control. Newly-diagnosed MGMT unmethylated GBMs and recurrent GBMs exceeding the PK threshold were eligible for an expansion phase of pamiparib (Arms A and B) or olaparib (Arm C) with concurrent RT followed by maintenance pamiparib or olaparib. RT was 60 Gy in 30 fractions in newly-diagnosed patients and 40 Gy in 15 fractions in recurrent patients, delivered using volumetric-modulated arc therapy (VMAT).

RESULTS

A total of 38 patients (Arm A, n = 16; Arm B, n = 16; Arm C, n = 6) were enrolled in the initial phase 0 study. The mean unbound concentrations of pamiparib in nonenhancing tumor region for Arm A and Arm B were 167.3 nM and 109.4 nM respectively, and in Arm C the mean unbound concentration of olaparib was 5.2 nM. All patients in the pamiparib arms (n = 32/32) but only 1 of 6 patients in the olaparib Arm C exceeded the PK threshold. Radiation-induced PAR expression was 2.44-fold in untreated control vs 1.16 in Arm A (p<0.05), 0.85 in Arm B (p<0.01) and 1.11 in Arm C patients, respectively. In Arm A, 11 patients had unmethylated tumors, and of those, 7 patients enrolled in phase 2. In Arm B, 9 of the 16 clinically eligible patients with positive PK results were enrolled in phase 2. At a median follow-up of 8.4 months [range: 1.3-15.7 months], the median progression-free survival (PFS) was 5.4, 6.0, and 3.8 months for Arms A (n = 7), B (n = 9), and C (n = 1), respectively. Grade 3+ toxicities related to pamiparib occurred in 4 patients, with 2 adverse events resulting in treatment discontinuation. No grade 3+ toxicities were documented in the olaparib arm.

CONCLUSION

Pamiparib achieved pharmacologically-relevant concentrations in nonenhancing GBM tissue and suppressed induction of PAR levels ex vivo post-radiation. The majority of patients with MGMT-unmethylated GBM advanced to the phase 2 portion of the trial, and pamiparib was generally well-tolerated in these patients.

A Combined Phase 0/2 "Trigger" Trial of Niraparib in Combination with Radiation in Patients with Newly-Diagnosed Glioblastoma

PURPOSE/OBJECTIVE(S)

Poly ADP-ribose (PAR) polymerase (PARP) mediates DNA damage response. Niraparib is an investigational PARP1/2-selective inhibitor. We conducted a combined phase 0/2 study to evaluate niraparib pharmacokinetics (PK) and pharmacodynamics (PD) in patients with newly-diagnosed glioblastoma (GBM), graduating patients to a phase 2 study evaluating a therapeutic regimen of niraparib with concurrent conventionally-fractionated radiotherapy (RT) in O6-methylguanine methyltransferase (MGMT) unmethylated tumors exceeding a prespecified PK threshold in non-enhancing tumor.

MATERIALS/METHODS

Patients with presumed newly-diagnosed GBM were enrolled in a phase 0 study receiving 4 days of niraparib (300 or 200 mg QD) prior to planned resection 3-5 or 8-12 hours following the last dose. Tumor tissue (enhancing and non-enhancing regions), cerebrospinal fluid (CSF), and plasma were collected. Total and unbound niraparib concentrations were measured using validated LC-MS/MS methods. PARP inhibition was assessed by quantification of PAR induction after 10 Gy ex vivo irradiation in surgical tissue compared to non-irradiated control tissue. A PK 'trigger' determined eligibility for the therapeutic phase 2 expansion portion of the study. This was defined as unbound [niraparib] > 5-fold biochemical IC50 (i.e., 19 nM) in non-enhancing tumor. Patients with MGMT unmethylated tumors exceeding this PK threshold were eligible for expansion phase dosing of niraparib with concurrent RT followed by a maintenance phase of niraparib. Patients with MGMT methylated tumors were not eligible for the expansion phase and proceeded with temozolomide (TMZ) plus RT followed by maintenance TMZ. RT dose was 60 Gy in 30 fractions using volumetric-modulated arc therapy (VMAT).

RESULTS

All 29 patients enrolled in the phase 0 portion of the study met the PK threshold. In non-enhancing regions, the mean unbound concentration of niraparib was 258.2 nM. The suppression of PAR levels after ex vivo RT was observed in 79% of the patients (17/22). Sixteen patients had unmethylated tumors, and of those, 11 patients enrolled in phase 2. Five of the 6 initial patients enrolled in phase 2 experienced thrombocytopenia related to niraparib, and 3/5 cases were deemed serious and life-threatening. Consequently, starting dose in both phases was lowered to 200 mg, and no serious AEs were observed thereafter. At a median follow-up of 8.1 months [range: 6.0-12.9 months], 6-month PFS was 64% with 4 patients remaining on treatment and 5 patients ongoing survival follow-up.

CONCLUSION

Niraparib achieves pharmacologically-relevant concentrations in non-enhancing, newly-diagnosed GBM tissue in excess of any other studied PARP inhibitor. When delivered with concurrent RT, niraparib was well-tolerated, with low rates of grade 3+ toxicity. Initial clinical efficacy data are encouraging.

Immune-mediated hematological disease in dogs is associated with alterations of the fecal microbiota: a pilot study

BACKGROUND

The dog is the most popular companion animal and is a valuable large animal model for several human diseases. Canine immune-mediated hematological diseases, including immune-mediated hemolytic anemia (IMHA) and immune thrombocytopenia (ITP), share many features in common with autoimmune hematological diseases of humans. The gut microbiome has been linked to systemic illness, but few studies have evaluated its association with immune-mediated hematological disease. To address this knowledge gap, 16S rRNA gene sequencing was used to profile the fecal microbiota of dogs with spontaneous IMHA and ITP at presentation and following successful treatment. In total, 21 affected and 13 healthy control dogs were included in the study.

RESULTS

IMHA/ITP is associated with remodeling of fecal microbiota, marked by decreased relative abundance of the spirochete Treponema spp., increased relative abundance of the pathobionts Clostridium septicum and Escherichia coli, and increased overall microbial diversity. Logistic regression analysis demonstrated that Treponema spp. were associated with decreased risk of IMHA/ITP (odds ratio [OR] 0.24-0.34), while Ruminococcaceae UCG-009 and Christensenellaceae R-7 group were associated with increased risk of disease (OR = 6.84 [95% CI 2-32.74] and 8.36 [95% CI 1.85-71.88] respectively).

CONCLUSIONS

This study demonstrates an association of immune-mediated hematological diseases in dogs with fecal dysbiosis, and points to specific bacterial genera as biomarkers of disease. Microbes identified as positive or negative risk factors for IMHA/ITP represent an area for future research as potential targets for new diagnostic assays and/or therapeutic applications.

Machine Learning Classification of Alzheimer's Disease Pathology Reveals Diffuse Amyloid as a Major Predictor of Cognitive Impairment in Human Hippocampal Subregions

Analyzing Alzheimer's disease (AD) pathology within anatomical subregions is a significant challenge, often carried out by pathologists using a standardized, semi-quantitative approach. To augment traditional methods, a high-throughput, high-resolution pipeline was created to classify the distribution of AD pathology within hippocampal subregions. USC ADRC post-mortem tissue sections from 51 patients were stained with 4G8 for amyloid, Gallyas for neurofibrillary tangles (NFTs) and Iba1 for microglia. Machine learning (ML) techniques were utilized to identify and classify amyloid pathology (dense, diffuse and APP (amyloid precursor protein)), NFTs, neuritic plaques and microglia. These classifications were overlaid within manually segmented regions (aligned with the Allen Human Brain Atlas) to create detailed pathology maps. Cases were separated into low, intermediate, or high AD stages. Further data extraction enabled quantification of plaque size and pathology density alongside ApoE genotype, sex, and cognitive status. Our findings revealed that the increase in pathology burden across AD stages was driven mainly by diffuse amyloid. The pre and para-subiculum had the highest levels of diffuse amyloid while NFTs were highest in the A36 region in high AD cases. Moreover, different pathology types had distinct trajectories across disease stages. In a subset of AD cases, microglia were elevated in intermediate and high compared to low AD. Microglia also correlated with amyloid pathology in the Dentate Gyrus. The size of dense plaques, which may represent microglial function, was lower in ApoE4 carriers. In addition, individuals with memory impairment had higher levels of both dense and diffuse amyloid. Taken together, our findings integrating ML classification approaches with anatomical segmentation maps provide new insights on the complexity of disease pathology in AD progression. Specifically, we identified diffuse amyloid pathology as being a major driver of AD in our cohort, regions of interest and microglial responses that might advance AD diagnosis and treatment.

Sustained intra-cartilage delivery of interleukin-1 receptor antagonist using cationic peptide and protein-based carriers

OBJECTIVE

Blocking the interleukin-1 (IL-1) catabolic cascade following joint trauma can be achieved using its receptor antagonist, IL-1Ra. However, its clinical translation for osteoarthritis therapy has been unsuccessful due to its rapid joint clearance and lack of targeting and penetration into deep cartilage layers at therapeutic concentrations. Here, we target the high negative charge of cartilage aggrecan-glycosaminoglycans (GAGs) by attaching cationic carriers to IL-1Ra. IL-1Ra was conjugated to the cartilage targeting glycoprotein, Avidin, and a short length optimally charged cationic peptide carrier (CPC+14). It is hypothesized that electro-diffusive transport and binding properties of IL-1Ra-Avidin and IL-1Ra-CPC+14 will create intra-cartilage depots of IL-1Ra, resulting in long-term suppression of IL-1 catabolism with only a single administration.

DESIGN

IL-1Ra was conjugated to Avidin or CPC+14 using site specific maleimide linkers, and confirmed using gel electrophoresis, high-performance liquid chromatography (HPLC), and mass spectrometry. Intra-cartilage transport and retention of conjugates was compared with native IL-1Ra. Attenuation of IL-1 catabolic signaling with one-time dose of IL-1Ra-CPC+14 and IL-1Ra-Avidin was assessed over 16 days using IL-1α challenged bovine cartilage and compared with unmodified IL-1Ra.

RESULTS

Positively charged IL-1Ra penetrated through the full-thickness of cartilage, creating a drug depot. A single dose of unmodified IL-1Ra was not sufficient to attenuate IL-1-induced cartilage deterioration over 16 days. However, when delivered using Avidin, and to a greater extent CPC+14, IL-1Ra significantly suppressed cytokine induced GAG loss and nitrite release while improving cell metabolism and viability.

CONCLUSION

Charge-based cartilage targeting drug delivery systems hold promise as they can enable long-term therapeutic benefit with only a single dose.

Study of spatiotemporal regulation of kinase signaling using genetically encodable molecular tools

Precise spatiotemporal organization and regulation of signal transduction networks are essential for cellular response to internal and external cues. To understand how this biochemical activity architecture impacts cellular function, many genetically encodable tools which regulate kinase activity at a subcellular level have been developed. In this review, we highlight various types of genetically encodable molecular tools, including tools to regulate endogenous kinase activity and biorthogonal techniques to perturb kinase activity. Finally, we emphasize the use of these tools alongside biosensors for kinase activity to measure and perturb kinase activity in real time for a better understanding of the cellular biochemical activity architecture.

Non-canonical β-adrenergic activation of ERK at endosomes

G-protein-coupled receptors (GPCRs), the largest family of signalling receptors, as well as important drug targets, are known to activate extracellular-signal-regulated kinase (ERK)-a master regulator of cell proliferation and survival1. However, the precise mechanisms that underlie GPCR-mediated ERK activation are not clearly understood2-4. Here we investigated how spatially organized β2-adrenergic receptor (β2AR) signalling controls ERK. Using subcellularly targeted ERK activity biosensors5, we show that β2AR signalling induces ERK activity at endosomes, but not at the plasma membrane. This pool of ERK activity depends on active, endosome-localized Gαs and requires ligand-stimulated β2AR endocytosis. We further identify an endosomally localized non-canonical signalling axis comprising Gαs, RAF and mitogen-activated protein kinase kinase, resulting in endosomal ERK activity that propagates into the nucleus. Selective inhibition of endosomal β2AR and Gαs signalling blunted nuclear ERK activity, MYC gene expression and cell proliferation. These results reveal a non-canonical mechanism for the spatial regulation of ERK through GPCR signalling and identify a functionally important endosomal signalling axis.

Artificial intelligence-guided, single-lead EKG may be a game-changer for symptom-to-balloon time reduction in ST-elevated myocardial infarction

Background

Over decades, efforts to shave off life-saving minutes from ST-Elevated Myocardial Infarction (STEMI) care centred on reducing door-to-needle and door-to-balloon times. We firmly believe that symptom-to-balloon time should prove a better focus to this end. Challenges come with this goal as it heavily relies on a patient's perception and initiative to seek care, which we deem intelligent and wearable Artificial Intelligence (AI)-driven Single Lead EKG technologies as an attractive solution in modern-day cardiology.

Purpose

To provide an accurate, accessible, and cost-effective AI-driven Single Lead STEMI detection algorithm that can be embedded into wearable devices and employed in a self-administered fashion.

Methods

Database: EKG records from Mexico, Colombia, Argentina, and Brazil from April 2014 to December 2019. Dataset: A total of 11,567 12-lead EKG records of 10[s] length with a sampling frequency of 500 Hz, including the following balanced classes: angiographically confirmed and unconfirmed STEMI, branch blocks, non-specific ST-T abnormalities, normal and abnormal (200+ CPT codes, excluding those mentioned above). Cardiologists manually checked the label of each record to ensure precision. Pre-processing: We discard the first and last 250 samples as they may contain a standardisation pulse. The study applied a digital low pass filter of order 5 with a frequency cut-off of 35 Hz. The mean was subtracted from each Lead. Classification: The determined classes were “STEMI” (Including STEMI in different locations of the myocardium – anterior, inferior, and lateral); and “Not-STEMI” (Combination of randomly sample, branch blocks, non-specific ST-T changes, and abnormal records – 25% of each). Training and Testing: A 1-D Convolutional Neural Network was trained and tested with a dataset proportion of 90/10, respectively. A different model was trained and tested for each Lead, using the central 4,500 samples of the records. The last dense layer outputs a probability for each report of being STEMI or Not-STEMI. Lead V2 showed the best overall results. The model was further tested through the same methodology using the best Lead with a subset of the previous data, excluding the unconfirmed STEMI EKG records (Total 7,230 12-lead EKG records for Confirmed Only STEMI dataset). Performance metrics were reported for each experiment and compared.

Results

Combined STEMI data: Accuracy: 91.2%; Sensitivity: 89.6%; Specificity: 92.9%. Confirmed STEMI Only dataset: Accuracy: 92.4%; Sensitivity: 93.4%; Specificity: 91.4% (Figure 1).

Conclusion

By assiduously improving the quality of the model's input, we continue to assess our algorithm's performance and reliability for future clinical validation as a potential remote monitoring and early STEMI detection device.

Funding Acknowledgement

Type of funding sources: None.

Digoxin improves systolic cardiac function in patients with AF and HFpEF: the RATE-AF randomised trial

Background

The RAte control Therapy Evaluation in permanent AF trial (RATE-AF; NCT02391337) was the first head-to-head controlled trial of beta-blockers versus digoxin in patients with permanent atrial fibrillation (AF) and symptoms of heart failure. Patients randomised to digoxin had similar physical-related quality of life and heart rate, with significantly improved functional class, reduced N-terminal pro-brain natriuretic peptide (NT-proBNP) and substantially less adverse events. The impact of rate control therapy on measures of cardiac function is not currently understood.

Purpose

To compare the effect of digoxin versus beta-blockers on systolic and diastolic cardiac function according to heart failure sub-type.

Methods

Blinded echocardiograms assessing systolic and diastolic function were performed at baseline and 12 month follow-up, using a robust method to account for rhythm irregularity (average of three index-beats acquired in appropriate cardiac cycles). Outcomes were the change in left-ventricular ejection fraction (LVEF), systolic tissue Doppler velocity (s'), stroke volume, global longitudinal strain (GLS), diastolic tissue Doppler (e'), mitral E wave deceleration time, E/e', pulmonary vein diastolic deceleration time, isovolumic relaxation time and left atrial ejection fraction. Analyses were stratified by baseline LVEF (≥50%, 40–50% and &lt;40%).

Results

160 patients were randomised, of which 145 patients survived to 12-month follow-up with median age 75 years (IQR 69–82) and 44% women. Median baseline heart rate was 96 beats/min (IQR 86–112), blood pressure 135/85 mmHg (IQR 124/77–146/91), NTproBNP 1049 pg/mL (744–1463) and mean NYHA class 2.4 (SD 0.6). In 119 patients with LVEF ≥50% at baseline, diastolic and systolic parameters improved over time with digoxin therapy. There was a significantly greater improvement in systolic function in 63 patients on digoxin compared to 67 with beta-blockers; Figure 1. Patients randomised to digoxin had a higher LVEF at follow-up (adjusted mean difference [AMD] 2.3%, 95% CI 0.3–4.2; p=0.021), higher s' (1.1cm/s, 1.0–1.2; p=0.003) and higher stroke volume (6.5mL, 0.4–12.6; p=0.037) compared to beta-blockers, without any difference in diastolic parameters (Figure 2). In 16 patients with LVEF 40–50% at baseline, s' significantly increased with digoxin compared to beta-blockers (AMD 1.5 cm/s, 1.2–1.7; p=0.001), with no difference for other systolic or diastolic parameters. 10 patients with LVEF &lt;40% at baseline showed no difference between digoxin and beta-blockers for any echocardiographic measures.

Conclusion

Patients randomised to digoxin with permanent AF, heart failure symptoms and preserved LVEF have significantly greater improvement in multiple parameters of systolic function compared to conventional treatment with beta-blockers.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): National Institute of Health Research

Performance metrics of AI-enhanced single lead EKG maintained after entry of organised clustered data

Background

Our experience in creating innovative Artificial Intelligence-guided single lead EKG methodologies for ST-Elevation Myocardial Infarction (STEMI) detection within complex EKG records has been previously validated.

Purpose

By expanding the intricate variables of our previously tested algorithm input, we seek to further improve our STEMI detecting tool.

Methods

11,567 12-lead EKG records (10-s length, 500 Hz sample frequency) derived from the Latin America Telemedicine Infarct Network database from April 2014 to December 2019. From these records, we included the following balanced classes: angiographically confirmed and unconfirmed STEMI (divided by wall affected), branch blocks, non-specific ST-T changes, normal, and abnormal (Remaining 200+ CPT codes). Cardiologist annotations ensured precision (Ground truth). Determined classes were “STEMI” and “Not-STEMI”. A 1-D Convolutional Neural Network model was trained and tested for each lead with dataset proportions of 90/10, respectively. The last dense layer outputs a probability for each record being STEMI/Not-STEMI. The analysis also included performance metrics and false-negative reports.

Results

Overall, the most promising Single lead for STEMI detection was V2 (91.2% Accuracy, 89.6% Sensitivity, and 92.9% Specificity). 55% of false negatives were inferior wall STEMI (Table 1).

Conclusion

Appreciable progress of our new methodology compared to our previous experiences in AI-guided Single Lead for STEMI detection, especially for lead V2. By performing a thorough analysis of false-negative reports, we aspire to identify potential areas of STEMI detection weakness which will become the focus of future ventures.

Funding Acknowledgement

Type of funding sources: None.

No need for a cardiologist for AMI diagnosis – progress of transforming a behemoth telemedicine program with artificial intelligence

Background

The Latin American Telemedicine Infarct Network (LATIN) Telemedicine is a mammoth hub and spoke model that provides an umbrella of AMI protection for 100 million patients. In the program, 826,043 patients had a telemedicine encounter; 7,400 with AMI were diagnosed; 4,332 of them managed with guidelines-based strategies. We have gradually begun implementing a system for using Artificial Intelligence (AI) algorithms embedded into EKGs for rapid and accurate STEMI detection and validated the results with a cardiologist's interpretations.

Purpose

To test whether an AI-driven EKG algorithm can effectively substitute a cardiologist for STEMI telemedicine protocols.

Methods

The AI algorithm construction was in the following fashion. Sample: a selection of 8,511 EKG and 90,592 classified heartbeats. Pre-processing: segmentation of each EKG into individual heartbeats. Training & testing: 90% and 10% of the total dataset, respectively. Classification: 1-D Convolutional Neural Network; the study constructed classes for each heartbeat. The algorithm was next deployed on a consecutive series of LATIN EKG records to diagnose STEMI. We afterwards compared the algorithm's results with eight expert cardiologists' interpretations of the same sample.

Results

This study achieved a concordance of 91% between the AI algorithm and cardiologist interpretation (Figure 1).

Conclusions

The initial results with AI algorithms for STEMI diagnosis are encouraging and may provide the base work for new tools for cardiologists to improve their efficiency. Moreover, implementing this innovative tool may overcome current limitations associated with the telemedical management of this disease.

Funding Acknowledgement

Type of funding sources: None.

Effect of aspirin discontinuation according to individualised patient bleeding and ischemic risks after PCI: a TWILIGHT trial sub-analysis

Background

The TWILIGHT trial demonstrated a reduction in BARC 2, 3 or 5 (BARC-235) bleeding without an increase in ischemic events at 1-year in high-risk PCI patients randomized to placebo or aspirin (ASA) on a background of ticagrelor 3-months after PCI. However, the effect of ASA discontinuation according to baseline risk of bleeding and ischemic events remain unclear.

Purpose

To a) develop separate models to predict the risk of bleeding and ischemic events, and b) to assess treatment effect of ASA discontinuation across the risk strata.

Methods

Using the TWILIGHT patient database (N=7,119), two multivariable models, one for BARC-235 bleeding and one for CV death, nonfatal MI or nonfatal ischemic stroke (ischemic endpoint) were developed, and their predictive capacity was assessed. The effect of randomized treatment on bleeding and ischemic events across different patient risk-group categories as determined by the risk scores was investigated.

Results

At 1-year, 350 (5.4%) patients experienced a BARC-235 bleeding event and 258 (3.6%) experienced an ischemic event. Independent predictors of BARC-235 included haemoglobin levels at index PCI, proton-pump inhibitor non-use at discharge, age, liver disease and active smoking (c-statistic 0.64). Independent predictors of the ischemic outcome included a positive troponin ACS, prior CABG, diabetes, age, peripheral artery disease, prior PCI, a history of congestive heart failure, active smoking, the level of index PCI complexity, and prior MI (c-statistic 0.71). The risk of a BARC-235 almost doubled between patients in lower versus higher bleeding risk categories (4.3% versus 7.9%) and ischemic risk more than tripled between patients in lower versus higher ischemic risk categories (2.0% versus 7.0%) (see Figure 1). There was no evidence of a differential treatment effect for dual antiplatelet therapy versus ticagrelor monotherapy across the different risk categories of bleeding (interaction P=0.54) and ischemic risk (interaction P=0.95) (Table 1).

Conclusion

Individual patient bleeding and ischemic risks after PCI can both be readily characterised with good discrimination. The effect of ASA discontinuation in preventing bleeding in ticagrelor-treated patients was consistent regardless of baseline bleeding risk. There was no evidence for increased ischemic events with ASA discontinuation according to baseline ischemic risk.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): AstraZenecaIcahn School of Medicine at Mount Sinai

A genetically encoded far-red fluorescent calcium ion biosensor derived from a biliverdin-binding protein

Far-red and near-infrared (NIR) genetically encoded calcium ion (Ca2+ ) indicators (GECIs) are powerful tools for in vivo and multiplexed imaging of neural activity and cell signaling. Inspired by a previous report to engineer a far-red fluorescent protein (FP) from a biliverdin (BV)-binding NIR FP, we have developed a far-red fluorescent GECI, designated iBB-GECO1, from a previously reported NIR GECI. iBB-GECO1 exhibits a relatively high molecular brightness, an inverse response to Ca2+ with ΔF/Fmin  = -13, and a near-optimal dissociation constant (Kd ) for Ca2+ of 105 nM. We demonstrate the utility of iBB-GECO1 for four-color multiplexed imaging in MIN6 cells and five-color imaging in HEK293T cells. Like other BV-binding GECIs, iBB-GECO1 did not give robust signals during in vivo imaging of neural activity in mice, but did provide promising results that will guide future engineering efforts. SIGNIFICANCE: Genetically encoded calcium ion (Ca2+ ) indicators (GECIs) compatible with common far-red laser lines (~630-640 nm) on commercial microscopes are of critical importance for their widespread application to deep-tissue multiplexed imaging of neural activity. In this study, we engineered a far-red excitable fluorescent GECI, designated iBB-GECO1, that exhibits a range of preferable specifications such as high brightness, large fluorescence response to Ca2+ , and compatibility with multiplexed imaging in mammalian cells.

P11.45.B Improved overall survival following Stereotactic Radiosurgery for brain metastases - a single institution experience

Background

Brain metastases are increasingly common due to longer survival associated with advancements in treatment. Approximately 40% of cancer patients are diagnosed with brain metastases at some point during their disease. Stereotactic radiosurgery (SRS) avoids the neuro-cognitive toxicity associated with whole brain radiotherapy and has been increasingly offered as a treatment alternative for brain metastases. Combined with developments in systemic treatments, this approach has resulted in improved overall survival (OS). This study reviewed patients treated with single fraction SRS at our institution with a primary endpoint of overall survival.

Material and Methods

A retrospective review determined overall survival for 237 patients who received single fraction SRS for 451 brain metastases from solid tumours between 1st January 2017 and 31st December 2021. Primary tumour sites were classified as breast, kidney, colorectal, melanoma, lung or other. SPSS v.27 was used for Kaplan Meier OS determination. The median follow up was 10.3 months. Cox regression analysis assessed the association between Gross Tumour Volume (GTV) and OS.

Results

In this patient cohort, 60% (N=142) were female and 40% (N=95) were male, with a median age of 63 [32-85]. 63.7% (N = 151) had a solitary metastasis. Patients received a single fraction of 15, 17.5 or 20 Gy (prescribed to 80% isodose) dependent on the planning target volume (PTV) size and whether it was initial treatment or re-treatment. 71% of all patients were alive at 6 months with median OS of 12.0 months [10.6-13.4]. Primary tumour site significantly affected OS (Log rank, Chi squared 15.656, p0.008) with breast cancer patients (N=58) surviving longest with a median OS 16.0 months [13.6-18.4] followed by melanoma median OS 15.0 months [7.6-22.4], kidney cancer patients (N = 24) median OS 12.0 months [8.3-15.7] and lung patients (N=87) median OS 10.0 months [8.9-11.3]. The lowest median OS was for colorectal patients at 7.0 months [1.4-12.6]. However, considering the small sample size, N = 15, more data is needed to confirm the significance. The larger the GTV volume the lower the survival time (Chi squared 8.692, p 0.003).

Conclusion

71% of patients had an OS of 6.0 months or more with a median of 12.0 months. As expected, primary tumour site has a significant impact on OS, with breast cancer patients living longest. In addition, increasing GTV size is associated with significantly worse survival. Given the improved survival for these patients, the avoidance of neuro cognitive decline remains of paramount importance and outcomes for these patients need to be reported in future work.

The influence of anastomotic techniques on postoperative anastomotic complications: Results of the Oesophago-Gastric Anastomosis Audit

BACKGROUND

The optimal anastomotic techniques in esophagectomy to minimize rates of anastomotic leakage and conduit necrosis are not known. The aim of this study was to assess whether the anastomotic technique was associated with anastomotic failure after esophagectomy in the international Oesophago-Gastric Anastomosis Audit cohort.

METHODS

This prospective observational multicenter cohort study included patients undergoing esophagectomy for esophageal cancer over 9 months during 2018. The primary exposure was the anastomotic technique, classified as handsewn, linear stapled, or circular stapled. The primary outcome was anastomotic failure, namely a composite of anastomotic leakage and conduit necrosis, as defined by the Esophageal Complications Consensus Group. Multivariable logistic regression modeling was used to identify the association between anastomotic techniques and anastomotic failure, after adjustment for confounders.

RESULTS

Of the 2238 esophagectomies, the anastomosis was handsewn in 27.1%, linear stapled in 21.0%, and circular stapled in 51.9%. Anastomotic techniques differed significantly by the anastomosis sites (P < .001), with the majority of neck anastomoses being handsewn (69.9%), whereas most chest anastomoses were stapled (66.3% circular stapled and 19.3% linear stapled). Rates of anastomotic failure differed significantly among the anastomotic techniques (P < .001), from 19.3% in handsewn anastomoses, to 14.0% in linear stapled anastomoses, and 12.1% in circular stapled anastomoses. This effect remained significant after adjustment for confounding factors on multivariable analysis, with an odds ratio of 0.63 (95% CI, 0.46-0.86; P = .004) for circular stapled versus handsewn anastomosis. However, subgroup analysis by anastomosis site suggested that this effect was predominantly present in neck anastomoses, with anastomotic failure rates of 23.2% versus 14.6% versus 5.9% for handsewn versus linear stapled anastomoses versus circular stapled neck anastomoses, compared with 13.7% versus 13.8% versus 12.2% for chest anastomoses.

CONCLUSIONS

Handsewn anastomoses appear to be independently associated with higher rates of anastomotic failure compared with stapled anastomoses. However, this effect seems to be largely confined to neck anastomoses, with minimal differences between techniques observed for chest anastomoses. Further research into standardization of anastomotic approach and techniques may further improve outcomes.

“Learning from the experts” – a novel advanced cadaveric course for Gynaecological Oncology (GO) Cytoreductive Surgery

Background: Ovarian cancer cytoreductive surgery necessitates the use of advanced Simulation-Based Learning (SBL) to optimise skill-based teaching and achieve technical proficiency. Objective: We describe and appraise the role of a novel postgraduate cadaveric course for cytoreductive surgery for advanced ovarian/fallopian tube or primary peritoneal cancer. Materials and Methods: Several consultant-level surgeons with expertise in upper gastrointestinal, colorectal, hepatobiliary and urological surgery, were invited to teach their counterpart GO surgeons. The 2-day course curriculum involved advanced dissections on thiel-embalmed cadavers. All dissections included applicable steps required during GO cytoreductive surgeries. Outcome measures: We used a feedback questionnaire and structured interviews to capture trainers and delegates views respectively. Results: All delegates reported a positive educational experience and improvement of knowledge in all course components. There was no difference in the perception of feedback across junior versus senior consultants. Trainers perceived this opportunity as a “2-way learning” whether they got to explore in depth the GO perspective in how and which of their skills are applicable during cytoreductive surgery. Conclusions: Collaborating with other surgical specialities promotes a “learning from the experts” concept and has potential to meet the rapidly increased demand for multi-viscera surgical excellence in GO surgery. What’s new? The concept of involving experts from other surgical disciplines in advanced cadaveric courses for cytoreductive surgery in ovarian cancer, will solidify the effort to achieve excellence in the GO training. Such courses can be essential educational adjunct for most GO fellowships.

AktAR and Akt-STOPS: Genetically Encodable Molecular Tools to Visualize and Perturb Akt Kinase Activity at Different Subcellular Locations in Living Cells

The serine/threonine protein kinase Akt integrates diverse upstream inputs to regulate cell survival, growth, metabolism, migration, and differentiation. Mounting evidence suggests that Akt activity is differentially regulated depending on its subcellular location, which can include the plasma membrane, endomembrane, and nuclear compartment. This spatial control of Akt activity is critical for achieving signaling specificity and proper physiological functions, and deregulation of compartment-specific Akt signaling is implicated in various diseases, including cancer and diabetes. Understanding the spatial coordination of the signaling network centered around this key kinase and the underlying regulatory mechanisms requires precise tracking of Akt activity at distinct subcellular compartments within its native biological contexts. To address this challenge, new molecular tools are being developed, enabling us to directly interrogate the spatiotemporal regulation of Akt in living cells. These include, for instance, the newly developed genetically encodable fluorescent-protein-based Akt kinase activity reporter (AktAR2), which serves as a substrate surrogate of Akt kinase and translates Akt-specific phosphorylation into a quantifiable change in Förster resonance energy transfer (FRET). In addition, we developed the Akt substrate tandem occupancy peptide sponge (Akt-STOPS), which allows biochemical perturbation of subcellular Akt activity. Both molecular tools can be readily targeted to distinct subcellular localizations. Here, we describe a workflow to study Akt kinase activity at different subcellular locations in living cells. We provide a protocol for using genetically targeted AktAR2 and Akt-STOPS, along with fluorescence imaging in living NIH3T3 cells, to visualize and perturb, respectively, the activity of endogenous Akt kinase at different subcellular compartments. We further describe a protocol for using chemically inducible dimerization (CID) to control the plasma membrane-specific inhibition of Akt activity in real time. Lastly, we describe a protocol for maintaining NIH3T3 cells in culture, a cell line known to exhibit robust Akt activity. In all, this approach enables interrogation of spatiotemporal regulation and functions of Akt, as well as the intricate signaling networks in which it is embedded, at specific subcellular locations. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Visualizing and perturbing subcellular Akt kinase activity using AktAR and Akt-STOPS Basic Protocol 2: Using chemically inducible dimerization (CID) to control inhibition of Akt at the plasma membrane Support Protocol: Maintaining NIH3T3 cells in culture.

Textbook outcome following oesophagectomy for cancer: international cohort study

Background

Textbook outcome has been proposed as a tool for the assessment of oncological surgical care. However, an international assessment in patients undergoing oesophagectomy for oesophageal cancer has not been reported. This study aimed to assess textbook outcome in an international setting.

Methods

Patients undergoing curative resection for oesophageal cancer were identified from the international Oesophagogastric Anastomosis Audit (OGAA) from April 2018 to December 2018. Textbook outcome was defined as the percentage of patients who underwent a complete tumour resection with at least 15 lymph nodes in the resected specimen and an uneventful postoperative course, without hospital readmission. A multivariable binary logistic regression model was used to identify factors independently associated with textbook outcome, and results are presented as odds ratio (OR) and 95 per cent confidence intervals (95 per cent c.i.).

Results

Of 2159 patients with oesophageal cancer, 39.7 per cent achieved a textbook outcome. The outcome parameter ‘no major postoperative complication’ had the greatest negative impact on a textbook outcome for patients with oesophageal cancer, compared to other textbook outcome parameters. Multivariable analysis identified male gender and increasing Charlson comorbidity index with a significantly lower likelihood of textbook outcome. Presence of 24-hour on-call rota for oesophageal surgeons (OR 2.05, 95 per cent c.i. 1.30 to 3.22; P = 0.002) and radiology (OR 1.54, 95 per cent c.i. 1.05 to 2.24; P = 0.027), total minimally invasive oesophagectomies (OR 1.63, 95 per cent c.i. 1.27 to 2.08; P &lt; 0.001), and chest anastomosis above azygous (OR 2.17, 95 per cent c.i. 1.58 to 2.98; P &lt; 0.001) were independently associated with a significantly increased likelihood of textbook outcome.

Conclusion

Textbook outcome is achieved in less than 40 per cent of patients having oesophagectomy for cancer. Improvements in centralization, hospital resources, access to minimal access surgery, and adoption of newer techniques for improving lymph node yield could improve textbook outcome.

Textbook outcome following oesophagectomy for cancer: international cohort study

BACKGROUND

Textbook outcome has been proposed as a tool for the assessment of oncological surgical care. However, an international assessment in patients undergoing oesophagectomy for oesophageal cancer has not been reported. This study aimed to assess textbook outcome in an international setting.

METHODS

Patients undergoing curative resection for oesophageal cancer were identified from the international Oesophagogastric Anastomosis Audit (OGAA) from April 2018 to December 2018. Textbook outcome was defined as the percentage of patients who underwent a complete tumour resection with at least 15 lymph nodes in the resected specimen and an uneventful postoperative course, without hospital readmission. A multivariable binary logistic regression model was used to identify factors independently associated with textbook outcome, and results are presented as odds ratio (OR) and 95 per cent confidence intervals (95 per cent c.i.).

RESULTS

Of 2159 patients with oesophageal cancer, 39.7 per cent achieved a textbook outcome. The outcome parameter 'no major postoperative complication' had the greatest negative impact on a textbook outcome for patients with oesophageal cancer, compared to other textbook outcome parameters. Multivariable analysis identified male gender and increasing Charlson comorbidity index with a significantly lower likelihood of textbook outcome. Presence of 24-hour on-call rota for oesophageal surgeons (OR 2.05, 95 per cent c.i. 1.30 to 3.22; P = 0.002) and radiology (OR 1.54, 95 per cent c.i. 1.05 to 2.24; P = 0.027), total minimally invasive oesophagectomies (OR 1.63, 95 per cent c.i. 1.27 to 2.08; P < 0.001), and chest anastomosis above azygous (OR 2.17, 95 per cent c.i. 1.58 to 2.98; P < 0.001) were independently associated with a significantly increased likelihood of textbook outcome.

CONCLUSION

Textbook outcome is achieved in less than 40 per cent of patients having oesophagectomy for cancer. Improvements in centralization, hospital resources, access to minimal access surgery, and adoption of newer techniques for improving lymph node yield could improve textbook outcome.

Liquid-liquid phase separation drives cellular function and dysfunction in cancer

Cancer is a disease of uncontrollably reproducing cells. It is governed by biochemical pathways that have escaped the regulatory bounds of normal homeostatic balance. This balance is maintained through precise spatiotemporal regulation of these pathways. The formation of biomolecular condensates via liquid-liquid phase separation (LLPS) has recently emerged as a widespread mechanism underlying the spatiotemporal coordination of biological activities in cells. Biomolecular condensates are widely observed to directly regulate key cellular processes involved in cancer cell pathology, and the dysregulation of LLPS is increasingly implicated as a previously hidden driver of oncogenic activity. In this Perspective, we discuss how LLPS shapes the biochemical landscape of cancer cells.

An International Registry of Peritoneal Carcinomatosis from Appendiceal Goblet Cell Carcinoma Treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

PURPOSE

Peritoneal carcinomatosis from appendiceal goblet cell carcinoma (A-GCC) is a rare and aggressive form of appendiceal tumor. Cytoreductive surgery (CRS) and hyperthermic intra peritoneal chemotherapy (HIPEC) was reported as an interesting alternative regarding survival compared to surgery without HIPEC and/or systemic chemotherapy. Our aim was to evaluate the impact of CRS and HIPEC for patients presenting A-GCC through an international registry.

METHODS

A prospective multicenter international database was retrospectively searched to identify all patients with A-GCC tumor and peritoneal metastases who underwent CRS and HIPEC through the Peritoneal Surface Oncology Group International (PSOGI). The post-operative complications, long-term results, and principal prognostic factors were analyzed.

RESULTS

The analysis included 83 patients. After a median follow-up of 47 months, the median overall survival (OS) was 34.6 months. The 3- and 5-year OS was 48.5% and 35.7%, respectively. Patients who underwent complete macroscopic CRS had a significantly better survival than those treated with incomplete CRS. The 5-year OS was 44% and 0% for patients who underwent complete, and incomplete CRS, respectively (HR 9.65, p < 0.001). Lymph node involvement and preoperative chemotherapy were also predictive of a worse prognosis. There were 3 postoperative deaths, and 30% of the patients had major complications.

CONCLUSION

CRS and HIPEC may increase long-term survival in selected patients with peritoneal metastases of A-GCC origin, especially when complete CRS is achieved. Ideally, randomized control trials or more retrospective data are needed to confirm CRS and HIPEC as the gold standard in this pathology.

Protocol for reading and imaging live-cell PKA activity using ExRai-AKAR2

Fluorescent protein (FP)-based kinase activity biosensors are powerful tools for probing the spatiotemporal dynamics of signaling pathways in living cells. Yet, the limited sensitivity of most kinase biosensors restricts their reliable application in high-throughput detection modalities. Here, we report a protocol for using an ultrasensitive excitation-ratiometric PKA activity reporter, ExRai-AKAR2, to detect live-cell PKA activity via fluorescence microplate reading and epifluorescence microscopy. The high sensitivity of ExRai-AKAR2 is well suited to these high-throughput applications. For complete details on the use and execution of this protocol, please refer to Mehta et al. (2018) andZhang et al., 2021a) .

Measuring Spatiotemporal cAMP Dynamics Within an Endogenous Signaling Compartment Using FluoSTEP-ICUE

cAMP is a ubiquitous second messenger involved in the regulation of diverse cellular processes. Spatiotemporal regulation of cAMP through compartmentalization within various subcellular microdomains is essential to ensure specific signaling. In the following protocol, we describe a method for directly visualizing signaling dynamics within cAMP microdomains using fluorescent sensors targeted to endogenous proteins (FluoSTEPs). Instead of overexpressing a biosensor-tagged protein of interest to target a microdomain, FluoSTEP Indicator of cAMP using Epac (FluoSTEP-ICUE) utilizes spontaneously complementing split GFP and CRISPR-Cas9 genome editing to localize a FRET-based cAMP biosensor to an endogenously expressed protein of interest. Utilizing this approach, FluoSTEP-ICUE can be used to measure cAMP levels within endogenous signaling compartments, thus providing a powerful tool for studying the spatiotemporal regulation of cAMP signaling.

Postoperative outcomes in oesophagectomy with trainee involvement

BACKGROUND

The complexity of oesophageal surgery and the significant risk of morbidity necessitates that oesophagectomy is predominantly performed by a consultant surgeon, or a senior trainee under their supervision. The aim of this study was to determine the impact of trainee involvement in oesophagectomy on postoperative outcomes in an international multicentre setting.

METHODS

Data from the multicentre Oesophago-Gastric Anastomosis Study Group (OGAA) cohort study were analysed, which comprised prospectively collected data from patients undergoing oesophagectomy for oesophageal cancer between April 2018 and December 2018. Procedures were grouped by the level of trainee involvement, and univariable and multivariable analyses were performed to compare patient outcomes across groups.

RESULTS

Of 2232 oesophagectomies from 137 centres in 41 countries, trainees were involved in 29.1 per cent of them (n = 650), performing only the abdominal phase in 230, only the chest and/or neck phases in 130, and all phases in 315 procedures. For procedures with a chest anastomosis, those with trainee involvement had similar 90-day mortality, complication and reoperation rates to consultant-performed oesophagectomies (P = 0.451, P = 0.318, and P = 0.382, respectively), while anastomotic leak rates were significantly lower in the trainee groups (P = 0.030). Procedures with a neck anastomosis had equivalent complication, anastomotic leak, and reoperation rates (P = 0.150, P = 0.430, and P = 0.632, respectively) in trainee-involved versus consultant-performed oesophagectomies, with significantly lower 90-day mortality in the trainee groups (P = 0.005).

CONCLUSION

Trainee involvement was not found to be associated with significantly inferior postoperative outcomes for selected patients undergoing oesophagectomy. The results support continued supervised trainee involvement in oesophageal cancer surgery.