Durability of Annuloplasty in Patients with Atrial Functional Mitral Regurgitation Associated with Atrial Fibrillation.

OBJECTIVE: To determine the durability of mitral valve repair with complete ring or flexible band annuloplasty in patients with atrial functional mitral regurgitation due to atrial fibrillation and identify risk factors associated with postoperative mitral regurgitation recurrence. METHODS: From 1/1/2000-1/1/2023, 194 adults with history of atrial fibrillation underwent mitral valve repair with annuloplasty alone for moderate/severe atrial functional mitral regurgitation. Exclusion criteria were prior cardiac surgery, additional repair techniques, ejection fraction<45%, ischemic heart disease, aortic valve disease, mitral annular calcification, and concomitant procedures other than surgical ablation or tricuspid repair/replacement. Durability of annuloplasty was assessed using longitudinal analysis of postoperative echo data. RESULTS: Complete ring annuloplasty was performed in 126/194(65%) patients; partial ring(posterior band) was chosen in 68/194(35%). Concomitantly, 64%(124/194) of patients underwent tricuspid valve surgery and 89%(173/194) an atrial fibrillation procedure, including biatrial Cox-Maze III/IV lesion set in 88%(152/173) and pulmonary vein isolation in 12%(21/173). All patients were discharged with no/trace mitral regurgitation. Freedom from moderate/severe mitral regurgitation after repair with annuloplasty alone was 89% at 10 years, and no significant differences were noted between complete vs. partial ring annuloplasty(early P=0.41, late P=0.92). Forty-eight percent of patients developed atrial fibrillation 3 or more months after surgery, and presence of postoperative atrial fibrillation was not associated with higher likelihood of recurrence of mitral regurgitation(P=0.15). Freedom from mitral reintervention was 96% at 10 years(Graphical Abstract). CONCLUSIONS: In appropriate patients with atrial functional mitral regurgitation, long-term durability of annuloplasty is excellent with complete ring and posterior band annuloplasty techniques.

The nuclear export protein XPO1 provides a peptide ligand for natural killer cells.

XPO1 (Exportin-1/CRM1) is a nuclear export protein that is frequently overexpressed in cancer and functions as a driver of oncogenesis. Currently small molecules that target XPO1 are being used in the clinic as anticancer agents. We identify XPO1 as a target for natural killer (NK) cells. Using immunopeptidomics, we have identified a peptide derived from XPO1 that can be recognized by the activating NK cell receptor KIR2DS2 in the context of human leukocyte antigen-C. The peptide can be endogenously processed and presented to activate NK cells specifically through this receptor. Although high XPO1 expression in cancer is commonly associated with a poor prognosis, we show that the outcome of specific cancers, such as hepatocellular carcinoma, can be substantially improved if there is concomitant evidence of NK cell infiltration. We thus identify XPO1 as a bona fide tumor antigen recognized by NK cells that offers an opportunity for a personalized approach to NK cell therapy for solid tumors.

Factors contributing to pesticide contamination in riverine systems: The role of wastewater and landscape sources.

Wastewater treatment plant (WWTP) discharges can be a source of organic contaminants, including pesticides, to rivers. An integrated model was developed for the Potomac River watershed (PRW) to determine the amount of accumulated wastewater (ACCWW) and calculate predicted environmental concentrations (PECs) for 14 pesticides in non-tidal National Hydrography Dataset Plus Version 2.1 stream segments. PECs were compared to measured environmental concentrations (MECs) from 32 stream sites that represented a range of ACCWW and land use to evaluate model performance and to assess possible non-WWTP loading sources. Agreement between PECs and MECs was strongest for insecticides, followed by fungicides and herbicides. Principal component analysis utilizing optical fluorescence and ancillary water quality data further separated wastewater from urban runoff sources. Pesticides that indicated relatively larger sources from WWTPs included dinotefuran, fipronil, carbendazim, thiabendazole, and prometon while imidacloprid, azoxystrobin, propiconazole, tebuconazole, and diuron were more strongly related to urban runoff. However, PECs generally comprised a low proportion of MECs, which suggests dominant loading sources beyond WWTP discharges. Cumulative potential toxicity was higher for sites with greater ACCWW and/or located in developed areas. Imidacloprid, fipronil, and carbendazim accounted for the largest portion of predicted potential toxicity across sites. The chronic aquatic life toxicity benchmarks for freshwater invertebrates were exceeded for 82 % of the imidacloprid detections (n = 28) and 47 % of the fipronil detections (n = 19). These results not only highlight the significant ecological implications of pesticide contamination from WWTP discharges but also underscores the potential legacy effects from accumulated soil and groundwater sources, emphasizing the need for management strategies to mitigate both current and historical impacts on aquatic ecosystems.

Illuminating Protein Allostery by Chemically Accurate Contact Response Analysis (ChACRA).

Decoding allostery at the atomic level is essential for understanding the relationship between a protein's sequence, structure, and dynamics. Recently, we have shown that decomposing temperature responses of inter-residue contacts can reveal allosteric couplings and provide useful insight into the functional dynamics of proteins. The details of this Chemically Accurate Contact Response Analysis (ChACRA) are presented here along with its application to two well-known allosteric proteins. The first protein, IGPS, is a model of ensemble allostery that lacks clear structural differences between the active and inactive states. We show that the application of ChACRA reveals the experimentally identified allosteric coupling between effector and active sites of IGPS. The second protein, ATCase, is a classic example of allostery with distinct active and inactive structural states. Using ChACRA, we directly identify the most significant residue level interactions underlying the enzyme's cooperative behavior. Both test cases demonstrate the utility of ChACRA's unsupervised machine learning approach for dissecting allostery at the residue level.

An α-ketoglutarate conformational switch controls iron accessibility, activation, and substrate selection of the human FTO protein.

The fat mass and obesity-associated fatso (FTO) protein is a member of the Alkb family of dioxygenases and catalyzes oxidative demethylation of N6-methyladenosine (m6A), N1-methyladenosine (m1A), 3-methylthymine (m3T), and 3-methyluracil (m3U) in single-stranded nucleic acids. It is well established that the catalytic activity of FTO proceeds via two coupled reactions. The first reaction involves decarboxylation of alpha-ketoglutarate (αKG) and formation of an oxyferryl species. In the second reaction, the oxyferryl intermediate oxidizes the methylated nucleic acid to reestablish Fe(II) and the canonical base. However, it remains unclear how binding of the nucleic acid activates the αKG decarboxylation reaction and why FTO demethylates different methyl modifications at different rates. Here, we investigate the interaction of FTO with 5-mer DNA oligos incorporating the m6A, m1A, or m3T modifications using solution NMR, molecular dynamics (MD) simulations, and enzymatic assays. We show that binding of the nucleic acid to FTO activates a two-state conformational equilibrium in the αKG cosubstrate that modulates the O2 accessibility of the Fe(II) catalyst. Notably, the substrates that provide better stabilization to the αKG conformation in which Fe(II) is exposed to O2 are demethylated more efficiently by FTO. These results indicate that i) binding of the methylated nucleic acid is required to expose the catalytic metal to O2 and activate the αKG decarboxylation reaction, and ii) the measured turnover of the demethylation reaction (which is an ensemble average over the entire sample) depends on the ability of the methylated base to favor the Fe(II) state accessible to O2.

Protein thermal sensing regulates physiological amyloid aggregation.

To survive, cells must respond to changing environmental conditions. One way that eukaryotic cells react to harsh stimuli is by forming physiological, RNA-seeded subnuclear condensates, termed amyloid bodies (A-bodies). The molecular constituents of A-bodies induced by different stressors vary significantly, suggesting this pathway can tailor the cellular response by selectively aggregating a subset of proteins under a given condition. Here, we identify critical structural elements that regulate heat shock-specific amyloid aggregation. Our data demonstrates that manipulating structural pockets in constituent proteins can either induce or restrict their A-body targeting at elevated temperatures. We propose a model where selective aggregation within A-bodies is mediated by the thermal stability of a protein, with temperature-sensitive structural regions acting as an intrinsic form of post-translational regulation. This system would provide cells with a rapid and stress-specific response mechanism, to tightly control physiological amyloid aggregation or other cellular stress response pathways.

Outbreak of Diarrhea Caused by a Novel Cryptosporidium hominis Subtype During British Military Training in Kenya.

Background: We report clinical, epidemiological, and laboratory features of a large diarrhea outbreak caused by a novel Cryptosporidium hominis subtype during British military training in Kenya between February and April 2022. Methods: Data were collated from diarrhea cases, and fecal samples were analyzed on site using the multiplex polymerase chain reaction (PCR) BioFire FilmArray. Water was tested using Colilert kits (IDEXX, UK). DNA was extracted from feces for molecular characterization of Cryptosporidium A135, Lib13, ssu rRNA, and gp60 genes. Results: One hundred seventy-two of 1200 (14.3%) personnel at risk developed diarrhea over 69 days. One hundred six primary fecal samples were tested, and 63/106 (59.4%; 95% CI, 0.49%-0.69%) were positive for Cryptosporidium spp. Thirty-eight had Cryptosporidium spp. alone, and 25 had Cryptosporidium spp. with ≥1 other pathogen. A further 27/106 (25.5%; 95% CI, 0.18%-0.35%) had non-Cryptosporidium pathogens only, and 16/106 (15.1%; 95% CI, 0.09%-0.23%) were negative. C. hominis was detected in 58/63 (92.1%) Cryptosporidium spp.-positive primary samples, but the others were not genotypable. Twenty-seven C. hominis specimens were subtypable; 1 was gp60 subtype IeA11G3T3, and 26 were an unusual subtype, ImA13G1 (GenBank accession OP699729), supporting epidemiological evidence suggesting a point source outbreak from contaminated swimming water. Diarrhea persisted for a mean (SD) of 7.6 (4.6) days in Cryptosporidium spp. cases compared with 2.3 (0.9) days in non-Cryptosporidium cases (P = .001). Conclusions: Real-time multiplex PCR fecal testing was vital in managing this large cryptosporidiosis outbreak. The etiology of a rare C. hominis gp60 subtype emphasizes the need for more genotypic surveillance to identify widening host and geographic ranges of novel C. hominis subtypes.

Validation of oxygen saturations measured in the community by emergency medical services as a marker of clinical deterioration in patients with confirmed COVID-19: a retrospective cohort study.

OBJECTIVES: To evaluate oxygen saturation and vital signs measured in the community by emergency medical services (EMS) as clinical markers of COVID-19-positive patient deterioration. DESIGN: A retrospective data analysis. SETTING: Patients were conveyed by EMS to two hospitals in Hampshire, UK, between 1 March 2020 and 31 July 2020. PARTICIPANTS: A total of 1080 patients aged ≥18 years with a COVID-19 diagnosis were conveyed by EMS to the hospital. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary study outcome was admission to the intensive care unit (ICU) within 30 days of conveyance, with a secondary outcome representing mortality within 30 days of conveyance. Receiver operating characteristic (ROC) analysis was performed to evaluate, in a retrospective fashion, the efficacy of different variables in predicting patient outcomes. RESULTS: Vital signs measured by EMS staff at the first point of contact in the community correlated with patient 30-day ICU admission and mortality. Oxygen saturation was comparably predictive of 30-day ICU admission (area under ROC (AUROC) 0.753; 95% CI 0.668 to 0.826) to the National Early Warning Score 2 (AUROC 0.731; 95% CI 0.655 to 0.800), followed by temperature (AUROC 0.720; 95% CI 0.640 to 0.793) and respiration rate (AUROC 0.672; 95% CI 0.586 to 0.756). CONCLUSIONS: Initial oxygen saturation measurements (on air) for confirmed COVID-19 patients conveyed by EMS correlated with short-term patient outcomes, demonstrating an AUROC of 0.753 (95% CI 0.668 to 0.826) in predicting 30-day ICU admission. We found that the threshold of 93% oxygen saturation is prognostic of adverse events and of value for clinician decision-making with sensitivity (74.2% CI 0.642 to 0.840) and specificity (70.6% CI 0.678 to 0.734).

Gut microbiome and antibiotic resistance effects during travelers' diarrhea treatment and prevention.

IMPORTANCE: The travelers' gut microbiome is potentially assaulted by acute and chronic perturbations (e.g., diarrhea, antibiotic use, and different environments). Prior studies of the impact of travel and travelers' diarrhea (TD) on the microbiome have not directly compared antibiotic regimens, and studies of different antibiotic regimens have not considered travelers' microbiomes. This gap is important to be addressed as the use of antibiotics to treat or prevent TD-even in moderate to severe cases or in regions with high infectious disease burden-is controversial based on the concerns for unintended consequences to the gut microbiome and antimicrobial resistance (AMR) emergence. Our study addresses this by evaluating the impact of defined antibiotic regimens (single-dose treatment or daily prophylaxis) on the gut microbiome and resistomes of deployed servicemembers, using samples collected during clinical trials. Our findings indicate that the antibiotic treatment regimens that were studied generally do not lead to adverse effects on the gut microbiome and resistome and identify the relative risks associated with prophylaxis. These results can be used to inform therapeutic guidelines for the prevention and treatment of TD and make progress toward using microbiome information in personalized medical care.

Survival and repair durability in patients undergoing concomitant aortic valve reimplantation and mitral valve repair.

Objective: The study objective was to determine repair durability and survival in patients with and without connective tissue disorders undergoing concomitant aortic valve reimplantation and mitral valve repair. Methods: From 2002 to 2019, 68 patients underwent concomitant aortic valve reimplantation and mitral valve repair, including 27 patients with Marfan syndrome (39.7%). Follow-up echocardiograms were analyzed using nonlinear multiphase mixed-effects cumulative logistic regression. The regurgitation grade over time was estimated by averaging patient-specific profiles. Survival and freedom from reoperation were estimated by the Kaplan-Meier method. Results: At 7 years, 11% of patients had aortic insufficiency greater than mild (severe in 2 patients). There was no difference in greater than mild aortic insufficiency between patients with or without Marfan syndrome (P = .37). Twenty percent of patients had progressed to mitral regurgitation greater than mild (severe in only 1 patient). The prevalence of recurrent mitral regurgitation was higher in those without Marfan syndrome, with greater than mild regurgitation increasing to 24% by 2 years and remaining constant thereafter (P = .04). Freedom from reoperation on the aortic valve or mitral valve was 83% at 10 years and did not differ between Marfan syndrome groups. There were no cases of perioperative mortality. Survival at 5 and 10 years was 94% and 87%, respectively, without a difference between those with and without Marfan syndrome. Conclusions: Patients can undergo a total repair strategy using combined aortic valve reimplantation and mitral valve repair procedures with a low risk of mortality and complications, with favorable freedom from both residual valve regurgitation and reoperation.

Temperature sensitive contact modes allosterically gate TRPV3.

TRPV Ion channels are sophisticated molecular sensors designed to respond to distinct temperature thresholds. The recent surge in cryo-EM structures has provided numerous insights into the structural rearrangements accompanying their opening and closing; however, the molecular mechanisms by which TRPV channels establish precise and robust temperature sensing remain elusive. In this work we employ molecular simulations, multi-ensemble contact analysis, graph theory, and machine learning techniques to reveal the temperature-sensitive residue-residue interactions driving allostery in TRPV3. We find that groups of residues exhibiting similar temperature-dependent contact frequency profiles cluster at specific regions of the channel. The dominant mode clusters on the ankyrin repeat domain and displays a linear melting trend while others display non-linear trends. These modes describe the residue-level temperature response patterns that underlie the channel's functional dynamics. With network analysis, we find that the community structure of the channel changes with temperature. And that a network of high centrality contacts connects distant regions of the protomer to the gate, serving as a means for the temperature-sensitive contact modes to allosterically regulate channel gating. Using a random forest model, we show that the contact states of specific temperature-sensitive modes are indeed predictive of the channel gate's state. Supporting the physical validity of these modes and networks are several residues identified with our analyses that are reported in literature to be functionally critical. Our results offer high resolution insight into thermo-TRP channel function and demonstrate the utility of temperature-sensitive contact analysis.

Branched stented anastomosis frozen elephant trunk repair: Early results from a physician-sponsored investigational device exemption study.

BACKGROUND: Multisegment thoracic aortic disease typically requires total aortic arch replacement, affects a heterogenous population, and carries a high risk even at centers of excellence. Risk has been associated with the duration of operation and complexity of repair. A novel branched stented anastomosis frozen elephant trunk repair (B-SAFER) technique has been developed at our center and is currently being studied as a physician-sponsored investigation device exemption (PS-IDE). OBJECTIVE: This study aimed to assess the early safety of using this investigational technique to treat the proximal aorta in subjects with aortic disease involving multiple segments. METHODS: This prospective, single center, nonrandomized study enrolled patients undergoing B-SAFER for acute aortic syndrome (n = 73), aortic aneurysm with chronic aortic dissection (n = 68), degenerative aortic aneurysm (n = 33), or congenital aortic arch disease (n = 4). Devices are delivered antegrade under hypothermic circulatory arrest, and the arch reconstruction is performed as a single anastomosis single stent (SASS; n = 70), single anastomosis multiple stent (SAMA; n = 68), multiple anastomosis single stent (MASS; n = 21), or multiple anastomosis multiple stent (MAMS; n = 16) reconstruction. The primary safety endpoints were operative mortality, disabling stroke, and paraparesis/paralysis. RESULTS: Between May 27, 2021, and December 31, 2022, 178 patients underwent B-SAFER in the configurations and for the indications as described above. The median patient age was 65 years (range, 21 to 85 years), and 52 (29%) were female. The median cardiopulmonary bypass time was 188 minutes (interquartile range [IQR], 155 to 226 minutes), and 97% of the patients underwent repair with antegrade brain perfusion for a median of 46 minutes (IQR, 38 to 61 minutes). Operative mortality occurred in 10 patients (5.6%, including 6 [8.2%] with acute dissection, 2 [2.9%] with chronic dissection, 2 [6.1%] with degenerative aneurysm, and 0 with a congenital disorder), disabling stroke in 5 patients (2.9%), and paraparesis in 1 patient. Other serious complications included respiratory failure (n = 20; 11.4%) and acute kidney injury (n = 18; 10%). Thirty-two patients (18%) had undergone second-stage repairs (28 endovascular and 4 open), with 1 operative mortality after that procedure due to distal rupture. Estimated survival was 95% at 30 days, 88% at 90 days, 84% at 6 months, and 79% at 1 year. One-year survival differed by indication (72% for acute dissection, 91% for chronic dissection, 71% for degenerative aneurysm, and 100% for congenital disorders). CONCLUSIONS: The B-SAFER technique for total arch replacement in a complex cohort of patients with various indications for surgery is a safe and reproducible operation, as demonstrated by the early results from a very inclusive PS-IDE study. Further follow-up and analysis will help refine the technique. Novel devices to perform this procedure should be developed.

TOMM40 '523 Genotype Distinguishes Patterns of Cognitive Improvement for Executive Function in APOEɛ3 Homozygotes.

BACKGROUND: TOMM40 '523 has been associated with cognitive performance and risk for developing Alzheimer's disease independent of the effect of APOE genotype. Few studies have considered the longitudinal effect of this genotype on change in cognition over time. OBJECTIVE: Our objective was to evaluate the relationship between TOMM40 genotype status and change in cognitive performance in the TOMMORROW study, which was designed to prospectively evaluate an algorithm that includes TOMM40 '523 for genetic risk for conversion to mild cognitive impairment. METHODS: We used latent growth curve models to estimate the effect of TOMM40 allele carrier (short, very long) status on the intercept and slope of change in cognitive performance in four broad cognitive domains (attention, memory, executive function, and language) and a combined overall cognitive score over 30 months. RESULTS: TOMM40 very long allele carriers had significantly lower baseline performance for the combined overall cognitive function score (B = -0.088, p = 0.034) and for the executive function domain score (B = -0.143, p = 0.013). Slopes for TOMM40 very long carriers had significantly greater increases over time for the executive function domain score only. In sensitivity analyses, the results for executive function were observed in participants who remained clinically stable, but not in those who progressed clinically over the study duration. CONCLUSIONS: Our results add to the growing body of evidence that TOMM40, in the absence of APOEɛ4, may contribute to cognitive changes with aging and dementia and support the view that mitochondrial function is an important contributor to Alzheimer's disease risk.