Assessing the Performance of Models from the 2022 RSNA Cervical Spine Fracture Detection Competition at a Level I Trauma Center.

"Just Accepted" papers have undergone full peer review and have been accepted for publication in Radiology: Artificial Intelligence. This article will undergo copyediting, layout, and proof review before it is published in its final version. Please note that during production of the final copyedited article, errors may be discovered which could affect the content. Purpose To evaluate the performance of the top models from the RSNA 2022 Cervical Spine Fracture Detection challenge on a clinical test dataset of both noncontrast and contrast-enhanced CT scans acquired at a level I trauma center. Materials and Methods Seven top-performing models in the RSNA 2022 Cervical Spine Fracture Detection challenge were retrospectively evaluated on a clinical test set of 1,828 CT scans (1,829 series: 130 positive for fracture, 1,699 negative for fracture; 1,308 noncontrast, 521 contrast-enhanced) from 1,779 patients (mean age, 55.8 ± 22.1 years; 1,154 male). Scans were acquired without exclusion criteria over one year (January to December 2022) from the emergency department of a neurosurgical and level I trauma center. Model performance was assessed using area under the receiver operating characteristic curve (AUC), sensitivity, and specificity. False positive and false negative cases were further analyzed by a neuroradiologist. Results Although all 7 models showed decreased performance on the clinical test set compared with the challenge dataset, the models maintained high performances. On noncontrast CT scans, the models achieved a mean AUC of 0.89 (range: 0.81-0.92), sensitivity of 67.0% (range: 30.9%-80.0%), and specificity of 92.9% (range: 82.1%-99.0%). On contrast-enhanced CT scans, the models had a mean AUC of 0.88 (range: 0.76-0.94), sensitivity of 81.9% (range: 42.7%-100.0%), and specificity of 72.1% (range: 16.4%-92.8%). The models identified 10 fractures missed by radiologists. False-positives were more common in contrast-enhanced scans and observed in patients with degenerative changes on noncontrast scans, while false-negatives were often associated with degenerative changes and osteopenia. Conclusion The winning models from the 2022 RSNA AI Challenge demonstrated a high performance for cervical spine fracture detection on a clinical test dataset, warranting further evaluation for their use as clinical support tools. ©RSNA, 2024.

Obstructive Sleep Apnea and Cerebral Small Vessel disease in Community-based Older People: An ASPREE Imaging Substudy.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) may increase risk of dementia. A potential pathway for this risk is through cerebral small vessel disease (CSVD). In the context of an existing randomized trial of aspirin for primary prevention, we aimed to investigate OSA's impact on CSVD imaging measures and explore whether aspirin effects these measures over 3 years that differ in the presence or absence of OSA. METHODS: A sub-study of the ASPirin in Reducing Events in the Elderly randomized placebo-controlled trial of low-dose aspirin. Community-dwelling participants aged 70 years and above, without cognitive impairment, cardiovascular disease or known OSA completed an unattended limited-channel sleep study that calculated the oxygen desaturation index and apnea-hypopnea index. At baseline and 3 years later, volumes of white matter hyperintensities (WMH) and silent brain infarctions (SBI) were measured on 1.5 Tesla brain magnetic resonance imaging, and retinal vessel calibers were calculated from retinal vascular imaging. RESULTS: Mild and moderate/severe OSA was detected in 48.9% and 29.9%, respectively, of the 311 participants, who had a mean age of 73.7 years (SD 3.4 years), 38.6% female. OSA of any severity did not associate with WMH volumes, SBI, nor with retinal vessel calibers at baseline, nor with change in these measures in the 277 participants with repeated measures acquired after 3 years. OSA of any severity did not interact with aspirin on change in these measures over 3 years. CONCLUSION: In healthy older adults undiagnosed OSA was not associated with retinal vascular calibers and neuroimaging measures of CSVD.

Impact of Nonalcoholic Hepatic Steatosis on the Warranty Period of a Coronary Artery Calcium Score of 0: Results From the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: For individuals with a coronary artery calcium (CAC) score of 0, CAC rescans at appropriate timings are recommended, depending on individual risk profiles. Although nonalcoholic fatty liver disease, recently redefined as metabolic-associated fatty liver disease, is a risk factor for atherosclerotic cardiovascular disease events, its relationship with the warranty period of a CAC score of 0 has not been elucidated. METHODS: A total of 1944 subjects from the MESA (Multi-Ethnic Study of Atherosclerosis) with a baseline CAC score of 0, presence or absence of nonalcoholic hepatic steatosis, and at least 1 follow-up computed tomography scan were included. Nonalcoholic hepatic steatosis was defined using nonenhanced computed tomography and liver/spleen attenuation ratio <1. The association between nonalcoholic hepatic steatosis and new CAC incidence (CAC score >0) was evaluated using a Weibull survival model. RESULTS: Nonalcoholic hepatic steatosis was identified in 268 (14%) participants. Participants with nonalcoholic hepatic steatosis had higher CAC incidence than those without nonalcoholic hepatic steatosis. Nonalcoholic hepatic steatosis was independently associated with new CAC incidence after adjustment for atherosclerotic cardiovascular disease risk factors (hazard ratio, 1.28 [95% CI, 1.05-1.57]; P=0.015). Using a 25% testing yield (25% of participants with zero CAC at baseline would be expected to have developed a CAC score >0), the warranty period of a CAC score of 0 in participants with nonalcoholic hepatic steatosis was shorter than in those without nonalcoholic hepatic steatosis (4.7 and 6.3 years). This association was consistent regardless of sex, race/ethnicity, age, and 10-year atherosclerotic cardiovascular disease risk. CONCLUSIONS: Nonalcoholic hepatic steatosis had an impact on the warranty period of a CAC score of 0. The study suggests that the time period until a CAC rescan should be shorter in those with nonalcoholic hepatic steatosis and a CAC score of 0.

Immunization of cows with HIV envelope trimers generates broadly neutralizing antibodies to the V2-apex from the ultralong CDRH3 repertoire.

The generation of broadly neutralizing antibodies (bnAbs) to conserved epitopes on HIV Envelope (Env) is one of the cornerstones of HIV vaccine research. The animal models commonly used for HIV do not reliably produce a potent broadly neutralizing serum antibody response, with the exception of cows. Cows have previously produced a CD4 binding site response by homologous prime and boosting with a native-like Env trimer. In small animal models, other engineered immunogens were shown to focus antibody responses to the bnAb V2-apex region of Env. Here, we immunized two groups of cows (n = 4) with two regimens of V2-apex focusing Env immunogens to investigate whether antibody responses could be generated to the V2-apex on Env. Group 1 was immunized with chimpanzee simian immunodeficiency virus (SIV)-Env trimer that shares its V2-apex with HIV, followed by immunization with C108, a V2-apex focusing immunogen, and finally boosted with a cross-clade native-like trimer cocktail. Group 2 was immunized with HIV C108 Env trimer followed by the same HIV trimer cocktail as Group 1. Longitudinal serum analysis showed that one cow in each group developed serum neutralizing antibody responses to the V2-apex. Eight and 11 bnAbs were isolated from Group 1 and Group 2 cows, respectively, and showed moderate breadth and potency. Potent and broad responses in this study developed much later than previous cow immunizations that elicited CD4bs bnAbs responses and required several different immunogens. All isolated bnAbs were derived from the ultralong CDRH3 repertoire. The finding that cow antibodies can target more than one broadly neutralizing epitope on the HIV surface reveals the generality of elongated structures for the recognition of highly glycosylated proteins. The exclusive isolation of ultralong CDRH3 bnAbs, despite only comprising a small percent of the cow repertoire, suggests these antibodies outcompete the long and short CDRH3 antibodies during the bnAb response.

Cardiovascular disease and stroke following cancer and cancer treatment in older adults.

BACKGROUND: Cancer survivors can be at risk of cardiovascular disease (CVD) because of either their malignancy or its treatment. Although studies linking cancer and CVD exist, few examine risk in older adults, the impact of cancer treatment, or the effect of aspirin on reducing risk in this cohort. METHODS: The authors conducted a secondary analysis of the Aspirin in Reducing Events in the Elderly (ASPREE) trial to investigate the impact of cancer and cancer treatment on a composite CVD end point comprising hospitalization for heart failure (HHF), myocardial infarction (MI), and stroke. RESULTS: Of 15,454 Australian and US ASPREE participants, 1392 had an incident cancer diagnosis. Rates of CVD were greater in the cancer risk-set compared to the cancer-free risk-set (20.8 vs. 10.3 events per 1000 person-years; incidence rate ratio, 2.03; 95% confidence interval, 1.51-2.66), with increased incidence seen across MI, HHF, overall stroke, and ischemic stroke. Increased incidence remained after adjustment for clinically significant risk factors for CVD. Incidence was greatest in metastatic, hematological, and lung cancer. Chemotherapy was associated with increased risk of CVD. Similar rates of CVD were seen across aspirin and placebo groups. CONCLUSIONS: Incidence of CVD, including MI, HHF, and ischemic stroke, was increased in older adults with cancer. Aspirin did not impact CVD incidence. Risk may be higher in those with metastatic, hematological, and lung cancer, and following chemotherapy.

Deep autoencoder-based behavioral pattern recognition outperforms standard statistical methods in high-dimensional zebrafish studies.

Zebrafish have become an essential model organism in screening for developmental neurotoxic chemicals and their molecular targets. The success of zebrafish as a screening model is partially due to their physical characteristics including their relatively simple nervous system, rapid development, experimental tractability, and genetic diversity combined with technical advantages that allow for the generation of large amounts of high-dimensional behavioral data. These data are complex and require advanced machine learning and statistical techniques to comprehensively analyze and capture spatiotemporal responses. To accomplish this goal, we have trained semi-supervised deep autoencoders using behavior data from unexposed larval zebrafish to extract quintessential "normal" behavior. Following training, our network was evaluated using data from larvae shown to have significant changes in behavior (using a traditional statistical framework) following exposure to toxicants that include nanomaterials, aromatics, per- and polyfluoroalkyl substances (PFAS), and other environmental contaminants. Further, our model identified new chemicals (Perfluoro-n-octadecanoic acid, 8-Chloroperfluorooctylphosphonic acid, and Nonafluoropentanamide) as capable of inducing abnormal behavior at multiple chemical-concentrations pairs not captured using distance moved alone. Leveraging this deep learning model will allow for better characterization of the different exposure-induced behavioral phenotypes, facilitate improved genetic and neurobehavioral analysis in mechanistic determination studies and provide a robust framework for analyzing complex behaviors found in higher-order model systems.

In Coping with Intimate Partner Violence, Women's Beliefs About Forgiveness Matter.

Women who experience intimate partner violence (IPV) often feel pressured to forgive their abusers and remain in dangerous relationships. However, forgiveness does not have to include reconciliation and it may be conceptualized in different ways. This quantitative study surveyed 110 women who experienced IPV from men and separated from their abusers. It then examined (a) the prevalence of 20 different beliefs about forgiveness and (b) the relationship between those beliefs, the women's self-reported practices of forgiveness, and the women's intent to return to their abusers. The study asked whether different beliefs about forgiveness were-in combination with different levels of forgiveness-associated with intent to return to abusers. It found that women's beliefs about forgiveness varied widely, but only 4.6% of the women believed that forgiveness involved reconciliation. In contrast, 80% of the women believed it was simultaneously possible to forgive and to avoid the men who hurt them. When interaction analyses were conducted, significant interactions were found between three beliefs and women's self-reported practices of forgiveness. For two beliefs, the interactions were positively associated with intent to return to abusers (i.e., a belief that forgiveness involves reconciliation, and a belief that forgiveness involves treating a person better than before). For one belief, the interaction was negatively associated with intent to return (i.e., the belief that it is possible both to forgive and to avoid a person). Results suggest that women's beliefs about forgiveness matter. Women are more likely to return to abusers if they believe forgiveness involves reconciliation or treating their abusers better than before. They are less likely to return, if they believe it is possible to forgive their abusers and still avoid them. Interventions targeting women's beliefs about forgiveness may increase their safety.

Potato Consumption and Risk of Type 2 Diabetes Mellitus: A Harmonized Analysis of 7 Prospective Cohorts.

BACKGROUND: Data on the relation of potato consumption with risk of type 2 diabetes (T2D) are limited and inconsistent. It is unclear whether the plant-based diet index (PDI), which is a novel and comprehensive tool to assess overall dietary pattern, modifies the association of potato intake with T2D. OBJECTIVES: We examined the association of total, combined baked, boiled, and mashed potatoes and fried potatoes with risk of T2D and test the interaction between PDI score and potato consumption on T2D risk. METHODS: We conducted a de novo, harmonized, individual-level data from 7 United States cohorts (N = 105,531). Cox regression was used to estimate hazard ratios (HRs) separately in each cohort adjusting for anthropometric, demographic, and lifestyle factors and cohort-specific results were pooled using an inverse-variance weighted method. RESULTS: Mean age ranged from 25 to 72 y, 65% women, and mean consumption of total potatoes ranged from 1.9 to 4.3 times per week. In the primary analysis, total potato intake was not associated with T2D risk: multivariable adjusted HR of 1.01 (95% confidence interval [CI]: 0.95, 1.08) for consumption of 1-2 servings/wk; 1.01 (95% CI: 0.93, 1.10) for >2-3 servings/wk; 1.05 (95% CI: 0.99, 1.12) for >3 to <5 servings/wk; and 1.07 (95% CI: 0.99, 1.16) for 5+ servings/wk compared with no potato intake. In secondary analyses, consumption of combined baked, boiled, and mashed potatoes was not associated with T2D risk, whereas fried potato consumption was positively associated with T2D risk: HR were 1 (ref), 1.07 (95% CI: 1.02, 1.12), and 1.12 (95% CI: 1.03, 1.22) for intake frequency of 0/wk, >0 to 1/wk, and >1/wk, respectively (P-trend = 0.04). There was no significant interaction between PDI score and potato consumption on T2D risk. CONCLUSIONS: Although consumption of total potato is not associated with T2D risk, a modest elevated risk of T2D is observed with fried potato consumption.

Cardiovascular Risks and Outcomes Among Chinese American Immigrants: Insights From the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: Immigrants experience changes in cardiovascular risk factors and racial disparities in both cardiovascular health prevention and outcomes upon immigration. We aimed to examine cardiovascular risk factors and outcomes among Chinese American immigrants enrolled in the MESA (Multi-Ethnic Study of Atherosclerosis) cohort. METHODS AND RESULTS: We analyzed data from 746 Chinese American immigrants in the MESA study with a median follow-up period of 17.8 years. The mean age of the cohort was 62.3 years, with 52.7% being women. Kaplan-Meier curves and Cox proportional hazards models were used to assess the association of immigration history, geographic location, biomarkers, and cardiac imaging parameters with cardiovascular risk factors and cardiovascular outcomes. The Cox hazards models were adjusted for known family history of heart disease, education level, sex, diabetes, hypertension, age, and body mass index. Although immigration history categorized as earlier (<20 years) versus later (≥20 years) showed no association with cardiovascular outcomes, the duration of residence in the United States emerged as a strong predictor for an increased risk of cardiovascular disease death (hazard ratio 1.39 [95% CI, 1.07-1.8]; P=0.012). All-cause mortality differed significantly between the Chinese immigrants from Los Angeles and those from Chicago, with higher survival probability in Chicago (log-rank test, P=0.018). Furthermore, elevated levels of N-terminal pro-brain natriuretic peptide levels, left ventricular mass, and coronary artery calcium scores were associated with the risk of cardiovascular disease among Chinese immigrants. CONCLUSIONS: Within the MESA cohort, the duration of residence and geographic location were associated with the risk of cardiovascular disease outcomes among Chinese immigrants.

Mediterranean Diet and Ultra-Processed Food Intake in Older Australian Adults-Associations with Frailty and Cardiometabolic Conditions.

Dietary patterns contribute to overall health and diseases of ageing but are understudied in older adults. As such, we first aimed to develop dietary indices to quantify Mediterranean Diet Score (MDS) utilisation and Ultra-processed Food (UPF) intake in a well-characterised cohort of relatively healthy community-dwelling older Australian adults. Second, we aimed to understand the relationship between these scores and the association of these scores with prevalent cardiometabolic disease and frailty. Our major findings are that in this population of older adults, (a) pre-frailty and frailty are associated with reduced MDS and increased UPF intake; (b) adherence to MDS eating patterns does not preclude relatively high intake of UPF (and vice versa); and (c) high utilisation of an MDS eating pattern does not prevent an increased risk of frailty with higher UPF intakes. As such, the Mediterranean Diet pattern should be encouraged in older adults to potentially reduce the risk of frailty, while the impact of UPF intake should be further explored given the convenience these foods provide to a population whose access to unprocessed food may be limited due to socioeconomic, health, and lifestyle factors.

Epigenetic age acceleration and cognitive performance over time in older adults.

INTRODUCTION: This study investigated whether epigenetic age acceleration (AA) is associated with the change in cognitive function and the risk of incident dementia over 9 years, separately in males and females. METHODS: Six epigenetic AA measures, including GrimAge, were estimated in baseline blood samples from 560 Australians aged ≥70 years (50.7% female). Cognitive assessments included global function, episodic memory, executive function, and psychomotor speed. Composite cognitive scores were also generated. Dementia (Diagnostic and Statistical Manual for Mental Disorders - IV [DSM-IV] criteria) was adjudicated by international experts. RESULTS: Associations between epigenetic AA and cognitive performance over-time varied by sex. In females only, GrimAA/Grim2AA was associated with worse delayed recall, composite cognition, and composite memory (adjusted-beta ranged from -0.1372 to -0.2034). In males only, GrimAA/Grim2AA was associated with slower processing speed (adjusted-beta, -0.3049) and increased dementia risk (adjusted hazard ratios [HRs], 1.78 and 2.00, respectively). DISCUSSION: Epigenetic AA is associated with cognitive deterioration in later life but with evidence of sex-specific associations. Highlights: Epigenetic age acceleration was associated with cognitive deterioration over time.However, these associations differed by sex.In females, accelerated GrimAge appeared to be a better marker of decline in memory.In males, accelerated GrimAge was associated with slower processing speed over time.Association between accelerated GrimAge and dementia risk was found only in males.

Antihypertensive medications and dementia in older adults with hypertension.

Background: Studies on middle-aged or individuals with cognitive or cardiovascular impairments, have established that intensive blood pressure (BP) control reduces cognitive decline risk. However, uncertainty exists on differential effects between antihypertensive medications (AHM) classes on this risk, independent of BP-lowering efficacy, particularly in community-dwelling hypertensive older adults. Methods: A post-hoc analysis of the ASPREE study, a randomized trial of low-dose aspirin in adults aged 70+ years (65+ if US minorities) without baseline dementia, and followed for two years post-trial. Cox proportional-hazards regression models were used to estimate associations between baseline and time-varying AHM exposure and incident dementia (an adjudicated primary trial endpoint), in participants with baseline hypertension. Subgroup analyses included prespecified factors, APO ε4 carrier status and monotherapy AHM use. Results: Most hypertensive participants (9,843/13,916; 70.7%) used AHMs. Overall, 'any' AHM use was not associated with lower incident dementia risk, compared with untreated participants (HR 0.84, 95%CI 0.70-1.02, p=0.08), but risk was decreased when angiotensin receptor blockers (ARBs) were included (HR 0.73, 95%CI 0.59-0.92, p=0.007). ARBs and ß-blockers decreased dementia risk, whereas angiotensin-converting enzyme inhibitors (ACEIs) and diuretics increased risk. There was no association with RAS modulating or blood-brain-barrier crossing AHMs on dementia risk. Conclusions: Overall, AHM exposure in hypertensive older adults was not associated with decreased dementia risk, however, specific AHM classes were with risk direction determined by class; ARBs and ß-blockers were superior to ACEIs and other classes in decreasing risk. Our findings emphasize the importance of considering effects beyond BP-lowering efficacy when choosing AHM in older adults.

Diverse PFAS produce unique transcriptomic changes linked to developmental toxicity in zebrafish.

Per- and polyfluoroalkyl substances (PFAS) are a widespread and persistent class of contaminants posing significant environmental and human health concerns. Comprehensive understanding of the modes of action underlying toxicity among structurally diverse PFAS is mostly lacking. To address this need, we recently reported on our application of developing zebrafish to evaluate a large library of PFAS for developmental toxicity. In the present study, we prioritized 15 bioactive PFAS that induced significant morphological effects and performed RNA-sequencing to characterize early transcriptional responses at a single timepoint (48 h post fertilization) after early developmental exposures (8 h post fertilization). Internal concentrations of 5 of the 15 PFAS were measured from pooled whole fish samples across multiple timepoints between 24-120 h post fertilization, and additional temporal transcriptomics at several timepoints (48-96 h post fertilization) were conducted for Nafion byproduct 2. A broad range of differentially expressed gene counts were identified across the PFAS exposures. Most PFAS that elicited robust transcriptomic changes affected biological processes of the brain and nervous system development. While PFAS disrupted unique processes, we also found that similarities in some functional head groups of PFAS were associated with the disruption in expression of similar gene sets. Body burdens after early developmental exposures to select sulfonic acid PFAS, including Nafion byproduct 2, increased from the 24-96 h post fertilization sampling timepoints and were greater than those of sulfonamide PFAS of similar chain lengths. In parallel, the Nafion byproduct 2-induced transcriptional responses increased between 48 and 96 h post fertilization. PFAS characteristics based on toxicity, transcriptomic effects, and modes of action will contribute to further prioritization of PFAS structures for testing and informed hazard assessment.

"It Will Always Feel Worse Because it Comes with That Added 'Betrayal'": Intersectionality Praxis and Black Young Women Survivors' Perspectives on Cultural Betrayal Trauma Theory.

Because of interlocking oppressions of racism and sexism (e.g. intersectionality), Black women's experiences of high rates of sexual violence are often ignored. A critical Black feminist framework, cultural betrayal trauma theory (CBTT) examines within-group violence in the Black community, which has compounding harm due to inequality. Though quantitative research has found support for CBTT, Black young women survivors' perspectives have not been examined. Therefore, the purpose of the current exploratory study was to engage in intersectionality praxis to qualitatively examine Black young women survivors' perspectives on CBTT through structured thematic analysis and coding based on theory. Respondents (N = 37; 18-30 years), provided their thoughts on CBTT following participating in a quantitative study. With most survivors in agreement that cultural betrayal in trauma is harmful, a key theme was community orientation in understanding both the harm and healing of cultural betrayal trauma. Black young women survivors' resonance with CBTT, as well as their recommendations for community-level solidarity and healing have important implications.

Co-targeting SOS1 enhances the antitumor effects of KRASG12C inhibitors by addressing intrinsic and acquired resistance.

Combination approaches are needed to strengthen and extend the clinical response to KRASG12C inhibitors (KRASG12Ci). Here, we assessed the antitumor responses of KRASG12C mutant lung and colorectal cancer models to combination treatment with a SOS1 inhibitor (SOS1i), BI-3406, plus the KRASG12C inhibitor, adagrasib. We found that responses to BI-3406 plus adagrasib were stronger than to adagrasib alone, comparable to adagrasib with SHP2 (SHP2i) or EGFR inhibitors and correlated with stronger suppression of RAS-MAPK signaling. BI-3406 plus adagrasib treatment also delayed the emergence of acquired resistance and elicited antitumor responses from adagrasib-resistant models. Resistance to KRASG12Ci seemed to be driven by upregulation of MRAS activity, which both SOS1i and SHP2i were found to potently inhibit. Knockdown of SHOC2, a MRAS complex partner, partially restored response to KRASG12Ci treatment. These results suggest KRASG12C plus SOS1i to be a promising strategy for treating both KRASG12Ci naive and relapsed KRASG12C-mutant tumors.

Mispacking of the F87 sidechain drives aggregation-promoting conformational fluctuations in the subunit interfaces of the transthyretin tetramer.

Aberrant formation and deposition of human transthyretin (TTR) aggregates causes transthyretin amyloidosis. To initialize aggregation, transthyretin tetramers must first dissociate into monomers that partially unfold to promote entry into the aggregation pathway. The native TTR tetramer (T) is stabilized by docking of the F87 sidechain into an interfacial cavity enclosed by several hydrophobic residues including A120. We have previously shown that an alternative tetramer (T*) with mispacked F87 sidechains is more prone to dissociation and aggregation than the native T state. However, the molecular basis for the reduced stability in T* remains unclear. Here we report characterization of the A120L mutant, where steric hindrance is introduced into the F87 binding site. The x-ray structure of A120L shows that the F87 sidechain is displaced from its docking site across the subunit interface. In A120S, a naturally occurring pathogenic mutant that is less aggregation-prone than A120L, the F87 sidechain is correctly docked, as in the native TTR tetramer. Nevertheless, 19F-NMR aggregation assays show an elevated population of a monomeric aggregation intermediate in A120S relative to a control containing the native A120, due to accelerated tetramer dissociation and slowed monomer tetramerization. The mispacking of the F87 sidechain is associated with enhanced exchange dynamics for interfacial residues. At 298 K, the T* populations of various naturally occurring mutants fall between 4% and 7% (ΔG ~ 1.5-1.9 kcal/mol), consistent with the free energy change expected for undocking and solvent exposure of one of the four F87 sidechains in the tetramer (ΔG ~ 1.6 kcal/mol). Our data provide a molecular-level picture of the likely universal F87 sidechain mispacking in tetrameric TTR that promotes interfacial conformational dynamics and increases aggregation propensity.

Serum Transaminases And Older Adults: Distribution And Associations With All-Cause Mortality.

BACKGROUND: Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are commonly ordered tests in general medical practice. However, their distribution and significance in older adults is understudied. As such, we aimed to evaluate sex-stratified distribution of both ALT and AST in older adults (≥ 70 years) and assess for associations with mortality. METHODS: Post-hoc analysis of the ASPirin in Reducing Events in the Elderly (ASPREE) randomised, placebo-controlled trial of daily low-dose aspirin for initially relatively healthy older persons. Univariate analysis and multiple logistic regression were used to explore baseline characteristics. Cox regression and restricted cubic splines were used to examine links between transaminase levels and mortality. RESULTS: Of the 11853 participants with ALT and AST levels, 1054 (8.9%) deaths were recorded over median 6.4 (IQR 5.4-7.6) years. For ALT, the lowest quintiles for males and females were 6-15 U/L and 5-13 U/L respectively; for AST, the lowest quintiles were 8-18 U/L and 7-17 U/L. On both univariate and models adjusted for covariates including age, BMI, frailty, diabetes, and kidney disease, males and females in the lowest quintile of ALT had an increased hazard of mortality (aHR 1.51 [95% CI 1.14-1.99] and aHR 1.39 [95% CI 1.03-1.88] respectively). For the lowest quintile of AST, only males were at increased risk (aHR 1.33 [95% CI 1.04-1.70]). Associations remained significant when removing outliers. CONCLUSION: Low ALT levels independently confer an increased hazard of mortality for older males and females; low AST only impacted older male survival. Further evaluation of mechanisms would be worthwhile, and re-evaluating the lower limit of normal for ALT in older adults should be considered.

AHR Dependent Toxicity by Retene Requires Metabolic Competence.

Polycyclic aromatic hydrocarbons (PAHs) are a class of organic compounds frequently detected in the environment with widely varying toxicities. Many PAHs activate the aryl hydrocarbon receptor (AHR), inducing the expression of a battery of genes, including xenobiotic metabolizing enzymes like Cytochrome P450s (CYPs); however, not all PAHs act via this mechanism. We screened several parent and substituted PAHs in in vitro AHR activation assays to classify their unique activity. Retene (1-methyl-7-isopropylphenanthrene) displays Ahr2 dependent teratogenicity in zebrafish, but did not activate human AHR or zebrafish Ahr2, suggesting a retene metabolite activates Ahr2 in zebrafish to induce developmental toxicity. To investigate the role of metabolism in retene toxicity, studies were performed to determine the functional role of cyp1a, cyp1b1, and the microbiome in retene toxicity, identify the zebrafish window of susceptibility, and measure retene uptake, loss, and metabolite formation in vivo. Cyp1a-null fish were generated using CRISPR-Cas9. Cyp1a-null fish showed increased sensitivity to retene toxicity, while Cyp1b1-null fish were less susceptible, and microbiome elimination had no significant effect. Zebrafish required exposure to retene between 24 and 48 hours post fertilization (hpf) to exhibit toxicity. After static exposure, retene concentrations in zebrafish embryos increased until 24 hpf, peaked between 24 and 36 hpf, and decreased rapidly thereafter. We detected retene metabolites at 36 and 48 hpf, indicating metabolic onset preceding toxicity. This study highlights the value of combining molecular and systems biology approaches with mechanistic and predictive toxicology to interrogate the role of biotransformation in AHR-dependent toxicity.

Daily low-dose aspirin and blood pressure in community-dwelling older adults.

High-quality randomized trial evidence is lacking on whether low-dose aspirin exerts significant effects on blood pressure (BP) in older adults. The authors assessed longitudinal BP changes in participants enrolled in ASPirin in Reducing Events in the Elderly (ASPREE), a randomized, placebo-controlled trial of 100 mg daily aspirin in 19 114 community-dwelling Australian and U.S. adults without cardiovascular disease (CVD), dementia, or independence-limiting physical disability. Participants' BP was recorded at baseline and annual study visits, and managed by their usual care provider. BP trajectories for aspirin versus placebo during 4.7 years of follow-up were examined for systolic and diastolic BP separately, using linear mixed models to account for between and within-individual variability in BP. Analyses by subgroups were also explored with inclusion of interaction terms in the models. The difference in mean change in systolic BP between aspirin and placebo during study follow-up was -0.03 mm Hg (95% confidence interval [CI]: -0.13, 0.07; p = .541) (aspirin minus placebo), while the mean difference for change in diastolic BP was -0.05 mm Hg (95% CI: -0.11, 0.01; p = .094). These small, non-significant differences in BP change between the aspirin and placebo groups were consistent across baseline levels of BP and antihypertensive treatment status (treated/untreated). Likewise, subgroups of age, sex, chronic kidney disease, diabetes, and frailty revealed no interaction effect between the subgroup, aspirin treatment, and time. Interval-censored Cox proportional hazards regression showed no difference in rates of incident treated hypertension between aspirin and placebo-treated participants. The authors conclude that daily low-dose aspirin does not significantly affect BP in older adults when managed by usual care.

Transcriptional function of E2A, Ebf1, Pax5, Ikaros and Aiolos analyzed by in vivo acute protein degradation in early B cell development.

Early B cell lymphopoiesis depends on E2A, Ebf1, Pax5 and Ikaros family members. In the present study, we used acute protein degradation in mice to identify direct target genes of these transcription factors in pro-B, small pre-B and immature B cells. E2A, Ebf1 and Pax5 predominantly function as transcriptional activators by inducing open chromatin at their target genes, have largely unique functions and are essential for early B cell maintenance. Ikaros and Aiolos act as dedicated repressors to cooperatively control early B cell development. The surrogate light-chain genes Igll1 and Vpreb1 are directly activated by Ebf1 and Pax5 in pro-B cells and directly repressed by Ikaros and Aiolos in small pre-B cells. Pax5 and E2A contribute to V(D)J recombination by activating Rag1, Rag2, Dntt, Irf4 and Irf8. Similar to Pax5, Ebf1 also represses the cohesin-release factor gene Wapl to mediate prolonged loop extrusion across the Igh locus. In summary, in vivo protein degradation has provided unprecedented insight into the control of early B cell lymphopoiesis by five transcription factors.