Photoresponsive hydrogel friction.

Photoresponsive hydrogels are an emerging class of stimuli-responsive materials that exhibit changes in physical or chemical properties in response to light. Previous investigations have leveraged photothermal mechanisms to achieve reversible changes in hydrogel friction, although few have focused on photochemical means. To date, the tribological properties of photoswitchable hydrogels (e.g., friction and lubrication) have remained underexplored. In this work, we incorporated photoresponsive methoxy-spiropyran-methacrylate monomers (methoxy-SP-MA) into a hydrogel network to form a copolymerized system of poly(N-isopropylacrylamide-co-2-acrylamido-2-methylpropane sulfonic acid-co-methoxy-spiropyran-methacrylate) (p(NIPAAm-co-AMPS-co-SP)). We demonstrated repeatable photoresponsive changes to swelling, friction, and stiffness over three light cycles. Our findings suggest that volume changes driven by the decreased hydrophilicity of the methoxy-SP-MA upon light irradiation are responsible for differences in the mechanical and tribological properties of our photoresponsive hydrogels. Our results could inform future designs of photoswitchable hydrogels for applications ranging from biomedical applications to soft robotics.

Full-fat dairy products and cardiometabolic health outcomes: Does the dairy-fat matrix matter?

Reducing dairy fat intake is a common dietary guideline to limit energy and saturated fatty acid intake for the promotion of cardiometabolic health. However, research utilizing a holistic, food-based approach to assess the consumption of the fat found in dairy, a broad and diverse food group, may provide new insight into these guidelines. Dairy fat is comprised of a diverse assembly of fatty acids, triacylglycerols, sterols, and phospholipids, all uniquely packaged in a milk fat globule. The physical structure of this milk fat globule and its membrane is modified through different processing methods, resulting in distinctive dairy-fat matrices across each dairy product. The objectives of this narrative review were to first define and compare the dairy-fat matrix in terms of its unique composition, physical structure, and fat content across common dairy products (cow's milk, yogurt, cheese, and butter). With this information, we examined observational studies and randomized controlled trials published within the last 10 years (2013-2023) to assess the individual effects of the dairy-fat matrix in milk, yogurt, cheese, and butter on cardiometabolic health and evaluate the implications for nutrition guidance. Searches conducted on Ovid MEDLINE and PubMed® utilizing search terms for cardiometabolic health, both broadly and regarding specific disease outcomes and risk factors, yielded 59 studies that were analyzed and included in this review. Importantly, this review stratifies by both dairy product and fat content. Though the results were heterogeneous, most studies reported no association between intake of these individual regular-fat dairy products and cardiometabolic outcome measures, thus, the current body of evidence suggests that regular-fat dairy product consumption may be incorporated within overall healthy eating patterns. Research suggests that there may be a beneficial effect of regular-fat milk and yogurt intake on outcome measures related to body weight and composition, and an effect of regular-fat cheese intake on outcome measures related to blood lipids, but more research is necessary to define the directionality of this relationship. Lastly, we identify methodological research gaps and propose future research directions to bolster the current evidence base available for ascertaining the role of dairy fat in a healthy diet.

Pollen effects in a changing climate: Ragweed pollen exposure and sleepiness in immunotherapy patients of a Southeastern Michigan allergy clinic.

Allergic rhino-conjunctivitis (AR) is a globally relevant health disorder characterized by sneezing, rhinorrhea and sleep disturbance. Ragweed (Ambrosia artemisiifolia) is a plant common to North America and an important allergen. Coarse methods of measuring airborne pollen counts are used to predict seasonal allergy symptoms. This research used a longitudinal study design with a novel, model-based raster of predicted pollen counts to test associations with self-reported symptoms of AR collected from patients receiving immunotherapy for pollen allergies at an allergy clinic. Researchers visited a clinic six times over three weeks. Immunotherapy patients were asked to fill out a brief intake survey on allergic and symptomatic profiles, daytime sleepiness, housing quality, and demographics. Participants responded to a daily, emailed survey on sleepiness and asthma symptoms for 21 days. Using the date and location of responses, ragweed pollen counts were extracted from a prognostic, model based raster (25km pixels). Lag associations of pollen counts with sleepiness were tested using a logistic regression model , adjusted for housing and demographic characteristics, in a distributed lag non-linear model (DLNM) framework. 49 people participated in the study. 26 (52%) were female. The mean age was 37.9 years. Asthma/allergy symptoms were not associated with ragweed pollen but sleepiness was highest two days after exposure (Estimate: 0.33 [0.04,0.62]). Subjects traveled widely during the study period. Intense exposures to ragweed pollen may be associated with daytime sleepiness within small exposure windows. Model-based predicted pollen counts could be used to study health impacts of pollen in people with disease severe enough to receive immunotherapy. Daytime sleepiness can affect productivity and injury risk, and pollen season length and allergenicity may be increasing with climate change. Thus our results may have important implications for population health.

Unveiling the electron-induced ionization cross sections and fragmentation mechanisms of 3,4-dihydro-2H-pyran.

The interactions of electrons with molecular systems under various conditions are essential to interdisciplinary research fields extending over the fundamental and applied sciences. In particular, investigating electron-induced ionization and dissociation of molecules may shed light on the radiation damage to living cells, the physicochemical processes in interstellar environments, and reaction mechanisms occurring in combustion or plasma. We have, therefore, studied electron-induced ionization and dissociation of the gas phase 3,4-dihydro-2H-pyran (DHP), a cyclic ether appearing to be a viable moiety for developing efficient clinical pharmacokinetics and revealing the mechanisms of biofuel combustion. The mass spectra in the m/z = 10-90 mass range were measured at several different energies of the ionizing electron beam using mass spectrometry. The mass spectra of DHP at the same energies were simulated using on-the-fly semi-classical molecular dynamics (MD) within the framework of the QCxMS formalism. The MD settings were suitably adjusted until a good agreement with the experimental mass spectra intensities was achieved, thus enabling a reliable assignment of cations and unraveling the plausible fragmentation channels. Based on the measurement of the absolute total ionization cross section of DHP (18.1 ± 0.9) × 10-16 cm2 at 100 eV energy, the absolute total and partial ionization cross sections of DHP were determined in the 5-140 eV electron energy. Moreover, a machine learning algorithm that was trained with measured cross sections from 25 different molecules was used to predict the total ionization cross section for DHP. Comparison of the machine learning simulation with the measured data showed acceptable agreement, similar to that achieved in past predictions of the algorithm.

Anatomical classification of canine congenital extrahepatic portosystemic shunts based on CT angiography: A SVSTS and VIRIES multi-institutional study in 1082 dogs.

Canine congenital extrahepatic portosystemic shunt (EHPSS) morphologies have not been fully elucidated. The goal of this retrospective, multi-institutional study was to use CT angiography to create an anatomical-based nomenclature system for canine congenital EHPSS. These shunt morphologies were then evaluated to identify any significant association with patient age, sex, breed, weight, or subjective portal perfusion score. Data collected respectively from the SVSTS and VIRIES list-serves included patient DOB, sex, breed, weight, CT date, and reported diagnosis. A single author (C.W.) viewed all CT scans and classified shunts based on the shunt portal vessel(s) of origin, the shunt systemic vessel(s) of insertion, and any substantial portal vessels contributing to the shunt. Additionally, hepatic portal perfusion was subjectively scored between one (poor/none) and five (good/normal) based on the caliber of the intrahepatic portal veins. A total of 1182 CT scans were submitted from 13 different institutions. Due to exclusion criteria, 100 (8.5%) were removed, leaving 1082 CT scans to be included. Forty-five different EHPSS anatomies were identified with five classifications accounting for 85% of all shunts (left gastric-phrenic [27%], left gastric-azygos [19%], left gastric-caval [15%], aberrant left gastric-caval with right gastric vein [12%], and aberrant left gastric-caval with right gastric vein and short gastric vein [11%]). Shunt origin involved the left gastric vein in 95% of the described classifications. Significant differences were identified among the five most common shunt types with respect to age at the time of the CT scan (P < .001), sex (P = .009), breed (P < .001), weight (P < .001), and subjective portal perfusion score (P < .001). An anatomical classification system for canine EHPSS may enable improved understanding, treatment comparisons, and outcome prediction for these patients.

Current frameworks for environmental and health assessment of hydrocarbon streams and products are flexible and ready for alternative non crude oil-based feeds.

Hazard and risk assessment of complex petroleum-derived substances has been in a state of continuous improvement since the 1970s, with the development of approaches that continue to be applied and refined. Alternative feeds are defined here as those coming into a refinery or chemical plant that are not hydrocarbons from oil and gas extraction such as biologically derived oils, pyrolysis oil from biomass or other, and recycled materials. These feeds are increasingly being used for production of liquid hydrocarbon streams, and hence, there is a need to assess these alternatives, subsequent manufacturing and refining processes and end products for potential risk to humans and the environment. Here we propose a tiered, problem formulation-driven framework for assessing the safety of hydrocarbon streams and products derived from alternative feedstocks in use. The scope of this work is only focused on petrochemical safety assessment, though the principles may be applicable to other chemistries. The framework integrates combinations of analytical chemistry, in silico and in vitro tools, and targeted testing together with conservative assumptions/approaches to leverage existing health, environmental, and exposure data, where applicable. The framework enables the identification of scenarios where de novo hazard and/or exposure assessments may be needed and incorporates tiered approaches to do so. It can be applied to enable decisions efficiently and transparently and can encompass a wide range of compositional space in both feedstocks and finished products, with the objective of ensuring safety in manufacturing and use.

Comparison of Minimally Invasive Chevron Akin and Open Lapidus Surgery in Older Patients at a Minimum 1-Year Follow-Up.

Background: Hallux valgus deformity affects more than 35% of people aged ≥65 years. Surgical correction in this population can be more complicated because of poor bone quality, worse deformity, and postoperative recovery challenges. The purpose of this study was to compare the radiographic and clinical outcomes of patients aged ≥65 years who underwent either open Lapidus or minimally invasive chevron Akin osteotomy for bunion correction. Methods: A retrospective review identified 62 patients aged ≥65 years who were treated surgically for hallux valgus with at least 1-year postoperative Patient-Reported Outcomes Measurement Information System (PROMIS) scores (physical function and pain interference). Preoperative and at least 6-month postoperative radiographs were measured for the hallux valgus angle and intermetatarsal angle. PROMIS scores were obtained preoperatively and at 1 and/or 2 years postoperatively. Differences in demographic, clinical, and radiographic outcomes were assessed using the Mann Whitney U test and P values were adjusted for a false discovery rate of 5%. Results: There was no difference between the MIS and open cohorts in pre- or postoperative radiographic measurements or clinical outcomes at any time point. At 1 year postoperatively, both groups had statistically significant improvements in the PROMIS pain interference domain but only the MIS group had a statistically significant improvement in the PROMIS physical function domain. Clinical significance was equivocal. At 2 years postoperatively, there were clinically and statistically significant improvements in the PROMIS pain interference and physical function domains for the open and MIS groups. Conclusion: Patients in both surgical groups had improvement in radiographic measurements and 2-year PROMIS scores, although there was no clinical or statistical difference found between groups. MIS and open surgical techniques appear to be safe and effective in correcting hallux valgus in older patients; however, patients may need to be counseled that maximum improvement after surgery may take more than 1 year. Level of Evidence: Level III, retrospective cohort study.

"It made me feel more alive": A qualitative analysis of quality of life improvements following completion of trauma-focused therapy for posttraumatic stress disorder.

Posttraumatic stress disorder (PTSD) is associated with poor quality of life. Although randomized clinical trial data show improvements in quality of life following trauma-focused therapies (TFTs), including prolonged exposure therapy (PE) and cognitive processing therapy (CPT), less is known about how these improvements are experienced from the trauma survivor's perspective. A national sample of 60 veterans who recently completed TFT as part of routine care at U.S. Department of Veterans Affairs facilities participated in semistructured qualitative interviews during which the impact of treatment on quality of life was explored. Following a mixed deductive/inductive approach, six interrelated themes describing changes in quality of life emerged: full participation in social activities, greater emotional intimacy in relationships, improvements in parenting, expanded engagement in hobbies and community, increased occupational commitment and confidence, and more joy in life. The data highlight the positive impact of treatment on quality of life and provide depth to quantitative findings demonstrating improvements in quality of life following TFT.

A Comparison of PROMIS Scores of Metatarsophalangeal Joint Arthrodesis and Polyvinyl Alcohol Hydrogel Implant Hemiarthroplasty for Hallux Rigidus.

Background: The current literature shows similar clinical outcomes between first metatarsophalangeal (MTP) joint arthrodesis and synthetic cartilage implant (SCI) hemiarthroplasty in the treatment of hallux rigidus; however, prior studies have not reported validated patient-reported outcome measures (PROMs). To our knowledge, this is the first study to compare PROMs using 6 domains of the validated Patient-Reported Outcomes Measurement Information System (PROMIS) in patients treated for hallux rigidus with MTP joint arthrodesis and with SCI hemiarthroplasty. In addition, this novel study provides comparative data on the complication and revision rates for each procedure. Methods: A single-center, retrospective registry search identified all patients with preoperative PROMIS scores who underwent MTP joint arthrodesis or SCI hemiarthroplasty for hallux rigidus between February 2016 and June 2021. The study aimed to determine if the 2 procedures showed statistically or clinically equivalent PROMIS scores in 6 domains: physical function, pain interference, pain intensity, global physical health, global mental health, and depression. A multivariable linear regression analysis was performed to compare adjusted 1-year postoperative PROMIS scores between the 2 cohorts. Complication and revision rates were also compared. Results: The study included 82 patients who underwent SCI hemiarthroplasty and 101 who underwent MTP joint arthrodesis. Demographic data and preoperative hallux rigidus severity showed no significant differences between the cohorts. PROMIS scores were mostly comparable between the 2 groups, except for the pain intensity domain. The patients who underwent MTP joint arthrodesis exhibited significantly better pain relief at 1 and 2 years postoperatively, which was supported by adjusted postoperative PROMIS scores. At 2 years, the SCI group had worse pain intensity scores and lower global physical health scores. There were no differences between the cohorts in additional PROMIS scores or complication data. Conclusions: While outcomes in most of the domains were similar, MTP joint arthrodesis was more effective at mitigating pain intensity compared with SCI hemiarthroplasty. This information can guide patient counseling and decision-making when considering surgical intervention for hallux rigidus. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

dia-PASEF Proteomics of Tumor and Stroma LMD Enriched from Archived HNSCC Samples.

We employed laser microdissection to selectively harvest tumor cells and stroma from the microenvironment of formalin-fixed, paraffin-embedded head and neck squamous cell carcinoma (HNSCC) tissues. The captured HNSCC tissue fractions were analyzed by quantitative mass spectrometry-based proteomics using a data independent analysis approach. In paired samples, we achieved excellent proteome coverage having quantified 6,668 proteins with a median quantitative coefficient of variation under 10%. We observed significant differences in relevant functional pathways between the spatially resolved tumor and stroma regions. Our results identified extracellular matrix (ECM) as a major component enriched in the stroma, including many cancer associated fibroblast signature proteins in this compartment. We demonstrate the potential for comparative deep proteome analysis from very low starting input in a scalable format that is useful to decipher the alterations in tumor and the stromal microenvironment. Correlating such results with clinical features or disease progression will likely enable identification of novel targets for disease classification and interventions.

Rapamycin increases murine lifespan but does not reduce mineral volume in the Matrix GLA Protein (MGP) knockout mouse model of medial arterial calcification.

Peripheral artery disease (PAD) is the narrowing of the arteries that carry blood to the lower extremities. PAD has been traditionally associated with atherosclerosis. However, recent studies have found that medial arterial calcification (MAC) is the primary cause of chronic limb ischemia below the knee. MAC involves calcification of the elastin fibers surrounding smooth muscle cells (SMCs) in arteries. Matrix GLA Protein (MGP) binds circulating calcium and inhibits vascular calcification. Mgp -/- mice develop severe MAC and die within 8 weeks of birth due to aortic rupture or heart failure. We previously discovered a rare genetic disease Arterial Calcification due to Deficiency in CD73 (ACDC) in which patients present with extensive MAC in their lower extremity arteries. Using a patient-specific induced pluripotent stem cell model we found that rapamycin inhibited calcification. Here we investigated whether rapamycin could reduce MAC in vivo using Mgp -/- mice as a model. Mgp +/+ and Mgp -/- mice received 5mg/kg rapamycin or vehicle. Calcification content was assessed via microCT, and vascular morphology and extracellular matrix content assessed histologically. Immunostaining and western blot analysis were used to examine SMC phenotypes and cellular functions. Rapamycin prolonged Mgp -/- mice lifespan, decreased mineral density in the arteries, and increased smooth muscle actin protein levels, however, calcification volume, vessel morphology, SMC proliferation, and autophagy flux were all unchanged. These findings suggest that rapamycin's effects in the Mgp -/- mouse are independent of the vascular phenotype.

Maternal prolactin or estrogen signaling in hepatocytes does not regulate iron homeostasis during pregnancy.

Not available.

Postoperative Hydration in Children Using Intermittent Boluses of Balanced Salt Solution: Results of a Randomized Control Trial.

BACKGROUND: Postoperative maintenance fluids are traditionally provided via hypotonic dextrose containing fluids administered intravenously by continuous infusion. We hypothesized that scheduled weight-based boluses of balanced salt solution would be more physiologic, reduce fluid volumes, and improve patient comfort. METHODS: As part of an IRB-approved randomized controlled trial (Boluses of Ringer's in Surgical Kids, BRiSK), we randomized patients aged 1-21 years undergoing elective abdominal or thoracic surgery to post-operatively receive weight-based D50.45NS+20mEq/L KCl at a continuous rate or intermittent boluses of Lactated Ringer's solution until oral liquid toleration. Patients with nephropathy, diabetes, or receiving parenteral nutrition were excluded. We analyzed electrolytes, urine output, fluid volume, and adverse events. RESULTS: We enrolled and randomized 60 patients: 29 to continuous fluids and 31 to bolus fluids. One patient from the bolus group dropped out. No patients crossed over due to difficulties with application of the bolus protocol. There were no baseline differences between groups with a mean age of 12.6 ± 1.4yr and weight of 50.9 ± 7.2 kg. There were no serious adverse events or electrolyte disturbances in either group. Patients in the bolus group received significantly less total fluid than those in the continuous group (0.43 mL/kg/h vs 1.1 mL/kg/h, p < 0.001) with no difference in urine output [1.4 ± 0.2 mL/kg/h vs 1.6 ± 0.3 mL/kg/h, p = 0.211]. There were two episodes of mild hypoglycemia in the bolus group compared to seven episodes of mild hyperglycemia in the continuous group. CONCLUSIONS: Administration of post-operative intravenous fluids as boluses of balanced salt solution is feasible, safe, and results in significantly less fluid administered compared to a traditional continuous protocol. LEVEL OF EVIDENCE: II.

Inhibitory actions of potentiating neuroactive steroids in the human α1ß3γ2L GABAA receptor.

The γ-aminobutyric acid type A (GABAA) receptor is modulated by a number of neuroactive steroids. Sulfated steroids and 3ß-hydroxy steroids inhibit while 3α-hydroxy steroids typically potentiate the receptor. Here, we have investigated inhibition of the α1ß3γ2L GABAA receptor by the endogenous neurosteroid 3α-hydroxy-5ß-pregnan-20-one (3α5ßP) and the synthetic neuroactive steroid 3α-hydroxy-5α-androstane-17ß-carbonitrile (ACN). The receptors were expressed in Xenopus oocytes. All experiments were done using two-electrode voltage-clamp electrophysiology. In the presence of low concentrations of GABA, 3α5ßP and ACN potentiate the GABAA receptor. To reveal inhibition, we conducted the experiments on receptors activated by the combination of a saturating concentration of GABA and propofol to fully activate the receptors and mask potentiation, or on mutant receptors in which potentiation is ablated. Under these conditions, both steroids inhibited the receptor with IC50s of ~13 µM and maximal inhibitory effects of 70-90%. Receptor inhibition by 3α5ßP was sensitive to substitution of the α1TM2-2' residue, previously shown to ablate inhibition by pregnenolone sulfate. However, results of coapplication studies and the apparent lack of state dependence suggest that pregnenolone sulfate and 3α5ßP inhibit the GABAA receptor independently and through distinct mechanisms. Mutations to the neurosteroid binding sites in the α1 and ß3 subunits significantly, albeit weakly and incompletely, reduced inhibition by 3α5ßP and ACN. Significance Statement The heteromeric GABAA receptor is inhibited by sulfated steroids and 3ß-hydroxy steroids while 3α-hydroxy steroids are considered to potentiate the receptor. We show here that 3α-hydroxy steroids have inhibitory effects on the α1ß3γ2L receptor, which are observed in specific experimental settings and are expected to manifest under different physiological conditions.

Effectiveness of Dry Cleaning Treatments for Removing Milk Chocolate from Valve/Pipe Assemblies and Pilot-scale Chocolate Processing Equipment.

Dark chocolate produced on equipment used to manufacture milk chocolate can contain milk due to cross-contact. This study evaluated the use of dry cleaning methods for removing milk chocolate residue from a butterfly or ball valve attached to a stainless steel pipe and from pilot-scale equipment used in chocolate manufacture. Milk-free dark chocolate (40 °C) was pumped through a milk chocolate-contaminated valve/pipe assembly after no cleaning, use of a pig purging treatment, or a 40 °C cocoa butter flush. Dark chocolate samples were collected at 7-sec intervals. Treatments investigated for the removal of residual milk chocolate from a conche and a ball mill included no cleaning, a 40 °C cocoa butter rinse, and wet cleaning. After cleaning, three batches of dark chocolate (40 °C) were processed in the ball mill and conche, and each batch was collected. Milk chocolate was processed on a 3-roll refiner, followed by push-through with dark chocolate (∼9 kg) with 0.3 kg samples collected at 5-min intervals. Dark chocolate samples were analyzed for milk concentrations by ELISA. Trials and analyses were completed in triplicate. Dark chocolate push-through alone resulted in milk concentrations ≥4,500 µg/g in samples obtained from the contaminated valve/pipe combinations within the first few seconds of collection, and ≥16.2 kg of dark chocolate was needed to obtain milk concentrations below the ELISA LOQ (2.5 µg/g). A pig purging treatment of the ball valve/pipe assembly resulted in milk concentrations below the ELISA LOQ. A cocoa butter flush of the butterfly valve/pipe decreased initial milk concentrations, but milk was detected until ≥18.7 kg dark chocolate purge. Milk concentrations in first batches of dark chocolate processed in a ball mill and conche without cleaning were ≥17,000 µg/g while the use of a cocoa butter rinse reduced milk levels in dark chocolate by ≥89%. Some dry cleaning treatments were effective at reducing levels of milk in dark chocolate due to cross-contact.

Next-Generation Contraceptive Intravaginal Ring: Comparison of Etonogestrel and Ethinyl Estradiol In Vitro and In Vivo Release from 3D-Printed Intravaginal Ring and NuvaRing.

Intravaginal rings (IVRs) represent a well-established, woman-controlled and sustained vaginal drug delivery system suitable for a wide range of applications. Here, we sought to investigate the differences in etonogestrel (ENG) and ethinyl estradiol (EE) release from a 3D-printed IVR utilizing continuous liquid interface production (CLIP™) (referred to as CLIPLOW for low drug loading and CLIPHIGH IVRs for high drug loading) and NuvaRing, a commercially available injection molded IVR. We conducted in vitro release studies in simulated vaginal fluid to compare the release of ENG and EE from CLIPLOW IVRs and NuvaRing. CLIPLOW IVRs had a similar hormone dose to NuvaRing and exhibited slightly slower ENG release and greater EE release in vitro compared to NuvaRing. When administered to female sheep, NuvaRing demonstrated greater ENG/EE levels in plasma, vaginal tissue and vaginal fluids compared to CLIPLOW IVR despite similar drug loadings. Leveraging observed hormones levels in sheep from NuvaRing as an effective contraceptive benchmark, we developed a long-acting CLIPHIGH IVR with increased ENG and EE doses that demonstrated systemic and local hormone levels greater than the NuvaRing for 90 days in sheep. No signs of toxicity were noted regarding general health, colposcopy, or histological analysis in sheep after CLIPHIGH IVR administration. Our results provided (1) a comparison of ENG and EE release between a 3D-printed IVR and NuvaRing in vitro and in vivo, (2) a preclinical pharmacokinetic benchmark for vaginally delivered ENG and EE and (3) the generation of a 90-day CLIP IVR that will be utilized in future work to support the development of a long-acting ENG/EE IVR combined with an antiretroviral for the prevention of HIV and unplanned pregnancy.

Synergistic effects of GFAP and Aß42: Implications for white matter integrity and verbal memory across the cognitive spectrum.

Background: Plasma glial fibrillary acidic protein (GFAP), an astrocytic biomarker, has previously been linked with Alzheimer's disease (AD) status, amyloid levels, and memory performance in older adults. The neuroanatomical pathways by which astrogliosis/astrocyte reactivity might impact cognitive outcomes remains unclear. We evaluated whether plasma GFAP and amyloid levels had a synergistic effect on fornix structure, which is critically involved in AD-associated cholinergic pathways. We also examined whether fornix structure mediates associations between GFAP and verbal memory. Methods: In a cohort of both asymptomatic and symptomatic older adults (total n = 99), we assessed plasma GFAP, amyloid-ß42 (Aß42), other AD-related proteins, and vascular markers, and we conducted comprehensive memory testing. Tractography-based methods were used to assess fornix structure with whole brain diffusion metrics to control for diffuse alterations in brain white matter. Results: In individuals in the low plasma amyloid-ß42 (Aß42) group, higher plasma GFAP was associated with lower fractional anisotropy (FA; p = 0.007), higher mean diffusivity (MD; p < 0.001), higher radial diffusivity (RD; p < 0.001), and higher axial diffusivity (DA; p = 0.001) in the left fornix. These associations were independent of APOE gene status, plasma levels of total tau and neurofilament light, plasma vascular biomarkers, and whole brain diffusion metrics. In a sub-analysis of participants in the low plasma Aß42 group (n = 33), fornix structure mediated the association between higher plasma GFAP levels and lower verbal memory performance. Discussion: Higher plasma GFAP was associated with altered fornix microstructure in the setting of greater amyloid deposition. We also expanded on our prior GFAP-verbal memory findings by demonstrating that in the low plasma Aß42 group, left fornix integrity may be a primary white matter conduit for the negative associations between GFAP and verbal memory performance. Overall, these findings suggest that astrogliosis/astrocyte reactivity may play an early, pivotal role in AD pathogenesis, and further demonstrate that high GFAP and low Aß42 in plasma may reflect a particularly detrimental synergistic role in forniceal-memory pathways.

A novel TREX1 inhibitor, VB-85680, upregulates cellular interferon responses.

Activation of the cGAS-STING pathway plays a key role in the innate immune response to cancer through Type-1 Interferon (IFN) production and T cell priming. Accumulation of cytosolic double-stranded DNA (dsDNA) within tumor cells and dying cells is recognized by the DNA sensor cyclic GMP-AMP synthase (cGAS) to create the secondary messenger cGAMP, which in turn activates STING (STimulator of INterferon Genes), resulting in the subsequent expression of IFN-related genes. This process is regulated by Three-prime Repair EXonuclease 1 (TREX1), a 3' → 5' exonuclease that degrades cytosolic dsDNA, thereby dampening activation of the cGAS-STING pathway, which in turn diminishes immunostimulatory IFN secretion. Here, we characterize the activity of VB-85680, a potent small-molecule inhibitor of TREX1. We first demonstrate that VB-85680 inhibits TREX1 exonuclease activity in vitro in lysates from both human and mouse cell lines. We then show that treatment of intact cells with VB-85680 results in activation of downstream STING signaling, and activation of IFN-stimulated genes (ISGs). THP1-Dual™ cells cultured under low-serum conditions exhibited an enhanced ISG response when treated with VB-85680 in combination with exogenous DNA. Collectively, these findings suggest the potential of a TREX1 exonuclease inhibitor to work in combination with agents that generate cytosolic DNA to enhance the acquisition of the anti-tumor immunity widely associated with STING pathway activation.

Loss of the alpha subunit distal furin cleavage site blunts ENaC activation following Na+ restriction.

Epithelial Na+ channels (ENaCs) are activated by proteolysis of the α and γ subunits at specific sites flanking embedded inhibitory tracts. To examine the role of α subunit proteolysis in channel activation in vivo, we generated mice lacking the distal furin cleavage site in the α subunit (αF2M mice). On a normal Na+ control diet, no differences in ENaC protein abundance in kidney or distal colon were noted between wild-type (WT) and αF2M mice. Patch-clamp analyses revealed similar levels of ENaC activity in kidney tubules, while no physiologically relevant differences in blood chemistry or aldosterone levels were detected. Male αF2M mice did exhibit diminished ENaC activity in the distal colon, as measured by amiloride-sensitive short-circuit current (ISC). Following dietary Na+ restriction, WT and αF2M mice had similar natriuretic and colonic ISC responses to amiloride. However, single-channel activity was significantly lower in kidney tubules from Na+-restricted αF2M mice compared with WT littermates. ENaC α and γ subunit expression in kidney and distal colon were also enhanced in Na+-restricted αF2M vs. WT mice, in association with higher aldosterone levels. These data provide evidence that disrupting α subunit proteolysis impairs ENaC activity in vivo, requiring compensation in response to Na+ restriction. KEY POINTS: The epithelial Na+ channel (ENaC) is activated by proteolytic cleavage in vitro, but key questions regarding the role of ENaC proteolysis in terms of whole-animal physiology remain to be addressed. We studied the in vivo importance of this mechanism by generating a mouse model with a genetic disruption to a key cleavage site in the ENaC's α subunit (αF2M mice). We found that αF2M mice did not exhibit a physiologically relevant phenotype under normal dietary conditions, but have impaired ENaC activation (channel open probability) in the kidney during salt restriction. ENaC function at the organ level was preserved in salt-restricted αF2M mice, but this was associated with higher aldosterone levels and increased expression of ENaC subunits, suggesting compensation was required to maintain homeostasis. These results provide the first evidence that ENaC α subunit proteolysis is a key regulator of channel activity in vivo.

Computed tomography-derived structural analysis for the likelihood of pathologic fracture in canine antebrachial osteosarcoma.

Determining the risk of pathologic fracture in dogs with a primary bone tumor would aid in case selection for in-situ treatment options. Prior research found strong relationships between in vitro strength of canine antebrachii with primary bone tumors and CT-derived metrics. This study assesses the prognosis for pathologic fracture in dogs with distal radial bone tumors using CT-derived structural analysis metrics. CT images of the antebrachium in dogs with aggressive osseous lesions of the radius were used to calculate structural rigidity and failure forces, including axial rigidity (AR), craniocaudal bending rigidity (BR), torsional rigidity (TR), and failure forces for a slightly-curved/asymmetric beam (Fs) or a curved beam (Fc). Metrics were compared with the clinical outcome of radial fracture. Eight of 19 dogs with CT-derived metrics developed a radial fracture. The prognostic potential of the metrics to discriminate fractured and nonfractured bones was analyzed using receiver operating characteristic curves (area under the curve), stepwise logistic regression, and classification regression (CART) analyses. Fc was the most sensitive and specific metric for prognosing fracture occurrence (AUC = 0.864). When dog body weight (BW) was included, all five metrics had AUC > 0.705. Fc was the best predictor of fracture using stepwise logistic regression and CART analysis, followed by BR. An indication of fracture probability can be determined by normalizing Fc or BR with dog BW or by using the logistic regression equation of either metric with dog BW. Results warrant further analysis of a larger cohort to evaluate fracture likelihood in dogs with antebrachial bone neoplasia.