Therapeutic expression of RAS Degrader RRSP in Pancreatic Cancer via Nanocarrier-mediated mRNA delivery.

About one-third of all human cancers encode abnormal RAS proteins locked in a constitutively activated state to drive malignant transformation and uncontrolled tumor growth. Despite progress in development of small molecules for treatment of mutant KRAS cancers, there is a need for a pan-RAS inhibitor that is effective against all RAS isoforms and variants and that avoids drug resistance. We have previously shown that the naturally occurring bacterial enzyme RAS/RAP1-specific endopeptidase (RRSP) is a potent RAS degrader that can be re-engineered as a biologic therapy to induce regression of colorectal, breast, and pancreatic tumors. Here, we have developed a strategy for in vivo expression of this RAS degrader via mRNA delivery using a synthetic nonviral gene delivery platform composed of the poly(ethylene glycol)-b-poly(propylene sulfide) (PEG-b-PPS) block copolymer conjugated to a dendritic cationic peptide (PPDP2). Using this strategy, PPDP2 is shown to deliver mRNA to both human and mouse pancreatic cells resulting in RRSP gene expression, activity, and loss of cell proliferation. Further, pancreatic tumors are reduced with residual tumors lacking detectable RAS and phosphorylated ERK. These data support that mRNA-loaded synthetic nanocarrier delivery of a RAS degrader can interrupt the RAS signaling system within pancreatic cancer cells while avoiding side effects during therapy.

Short-term Outcomes After Hip Arthroscopic Surgery in Patients Participating in Formal Physical Therapy Versus a Home Exercise Program: A Prospectively Enrolled Cohort Analysis.

BACKGROUND: Physical therapy is frequently utilized in the postoperative care of femoroacetabular impingement syndrome (FAIS). There has been limited research into the efficacy of a structured home exercise program (HEP) compared with formal physical therapy (FPT) in this patient population. PURPOSE/HYPOTHESIS: The purpose was to evaluate the short-term outcomes of patients utilizing FPT versus an HEP after hip arthroscopic surgery for FAIS. It was hypothesized that both groups would show similar improvements regarding outcome scores, which would improve significantly compared with their preoperative scores. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Patients undergoing hip arthroscopic surgery for FAIS at a single center between October 2020 and October 2021 were prospectively enrolled. Patients were allowed to self-select FPT or an HEP and were administered a survey preoperatively and at 1 month, 3 months, 6 months, and 12 months postoperatively. The survey included the Single Assessment Numeric Evaluation, visual analog scale for pain, 12-item International Hip Outcome Tool, Patient-Reported Outcomes Measurement Information System Physical Function, and patient satisfaction with physical therapy and overall care. Statistical analysis was conducted between the 2 groups and within groups to compare preoperative and postoperative scores. RESULTS: The patients' mean age was 32.6 ± 10.4 years, with 47.2% being female and 57.4% choosing the HEP. At 12 months postoperatively, no significant differences were reported between the FPT and HEP groups regarding the Single Assessment Numeric Evaluation score (P = .795), visual analog scale for pain score (P > .05), Patient-Reported Outcomes Measurement Information System Physical Function T-score (P = .699), 12-item International Hip Outcome Tool score (P = .582), and patient satisfaction (P > .05). Outcome scores at 12 months postoperatively were significantly improved from the preoperative scores across all measures in both groups (P < .001). CONCLUSION: There were no significant differences regarding patient outcomes between FPT and the HEP at 1-year follow-up after hip arthroscopic surgery for FAIS when patients selected their own treatment, with both groups demonstrating significant improvements in their outcome scores from their preoperative values. These findings suggest that a structured HEP may be a viable alternative to FPT after hip arthroscopic surgery in patients who prefer a self-directed rehabilitation program.

Dynamic Estimation of Cardiovascular State From Arterial Blood Pressure Recordings.

Real-time estimation of patient cardiovascular states, including cardiac output and systemic vascular resistance, is necessary for personalized hemodynamic monitoring and management. Highly invasive measurements enable reliable estimation of these states but increase patient risk. Prior methods using minimally invasive measurements reduce patient risk but have produced unreliable estimates limited due to trade-offs in accuracy and time resolution. Our objective was to develop an approach to estimate cardiac output and systemic vascular resistance with both a high time resolution and high accuracy from minimally invasive measurements. Using the two-element Windkessel model, we formulated a state-space method to estimate a dynamic time constant - the product of systemic vascular resistance and compliance - from arterial blood pressure measurements. From this time constant, we derived proportional estimates of systemic vascular resistance and cardiac output. We then validated our method with a swine cardiovascular dataset. Our estimates produced using arterial blood pressure measurements not only closely align with those using highly invasive measurements, but also closely align when derived from three separate locations on the arterial tree. Moreover, our estimates predictably change in response to standard cardiovascular drugs. Overall, our approach produces reliable, real-time estimates of cardiovascular states crucial for monitoring and control of the cardiovascular system.

Social determinants of health inequalities in early phase clinical trials in Northern England.

BACKGROUND: Early phase clinical trials in Oncology represent a subspecialised area where UK patient selection is influenced by access to Experimental Cancer Medicine Centres (ECMCs). Equity of access with respect to social determinants of health (SDoH) were explored for two major ECMCs. METHODS: A retrospective cohort study including all referrals to Newcastle and Manchester ECMCs in 2021 was completed. Consent to screening or pre-screening was stratified against SDoH characteristics, including: Index of Multiple Deprivation (IMD) decile, ethnicity and distance to centre. RESULTS: 1243 patients were referred for trials. IMD quintile 1 (most deprived) patients had reduced likelihood of referral compared to expected population models (OR, 0.67; 95% CI: 0.55 to 0.80, p = <0.0001). IMD quintile 5 (least deprived) had increased likelihood of referral (OR, 1.46; 95% CI: 1.17 to 1.82, p = 0.0007). Living beyond median distance from Manchester reduced the likelihood of consenting to trials (OR, 0.72; 95% CI: 0.55 to 0.94, p = 0.015). Ethnicity data represented a White British propensity. CONCLUSIONS: Inequalities in socioeconomic and geographic factors influence referral and enrolment to early phase clinical trials in Northern England. This has implications for equity of access and generalisability of trial results internationally and warrants further study.

A Case Report of Sepsis Secondary to Perforated Cholecystitis in the Presence of Severe Aortic Stenosis: Diagnosis and Management.

Gallbladder perforation is a rare complication of acute cholecystitis that is associated with significant morbidity and mortality. Many cases of gallbladder perforation are not diagnosed until surgery, as the physical symptoms closely mimic acute cholecystitis. Gallbladder perforation is most common among older males with associated comorbidities, and preoperative assessment of comorbidities, particularly cardiac, is critical to determine the appropriate clinical course. We report a case of a 77-year-old male who presented initially with low blood pressure and right upper quadrant pain (RUQ) after not feeling well for five days. CT of the abdomen/pelvis with IV contrast demonstrated acute perforated cholecystitis, and general surgery was consulted for a cholecystectomy. Due to the patient's past medical history of severe aortic stenosis (AS), cholecystectomy was deferred and a cholecystostomy tube was placed by interventional radiology. This report aims to provide an example of a case of perforated cholecystitis with sepsis and how it can be diagnosed and managed non-surgically in the presence of pre-existing severe AS.

Litchi (Litchi chinensis Sonn.): A comprehensive and critical review on cancer prevention and intervention.

Litchi (Litchi chinensis Sonn.) is a tropical fruit with various health benefits. The objective of this study is to present a thorough analysis of the cancer preventive and anticancer therapeutic properties of litchi constituents and phytocompounds. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis criteria were followed in this work. Various litchi extracts and constituents were studied for their anticancer effects. In vitro studies showed that litchi-derived components reduced cell proliferation, induced cytotoxicity, and promoted autophagy via increased cell cycle arrest and apoptosis. Based on in vivo studies, litchi flavonoids and other extracted constituents significantly reduced tumor size, number, volume, and metastasis. Major signaling pathways impacted by litchi constituents were shown to stimulate proapoptotic, antiproliferative, and antimetastatic activities. Despite promising antineoplastic activities, additional research, especially in vivo and clinical studies, is necessary before litchi-derived products and phytochemicals can be used for human cancer prevention and intervention.

A metabolic inhibitor blocks cellular fucosylation and enables production of afucosylated antibodies.

The fucosylation of glycoproteins regulates diverse physiological processes. Inhibitors that can control cellular levels of protein fucosylation have consequently emerged as being of high interest. One area where inhibitors of fucosylation have gained significant attention is in the production of afucosylated antibodies, which exhibit superior antibody-dependent cell cytotoxicity as compared to their fucosylated counterparts. Here, we describe ß-carbafucose, a fucose derivative in which the endocyclic ring oxygen is replaced by a methylene group, and show that it acts as a potent metabolic inhibitor within cells to antagonize protein fucosylation. ß-carbafucose is assimilated by the fucose salvage pathway to form GDP-carbafucose which, due to its being unable to form the oxocarbenium ion-like transition states used by fucosyltransferases, is an incompetent substrate for these enzymes. ß-carbafucose treatment of a CHO cell line used for high-level production of the therapeutic antibody Herceptin leads to dose-dependent reductions in core fucosylation without affecting cell growth or antibody production. Mass spectrometry analyses of the intact antibody and N-glycans show that ß-carbafucose is not incorporated into the antibody N-glycans at detectable levels. We expect that ß-carbafucose will serve as a useful research tool for the community and may find immediate application for the rapid production of afucosylated antibodies for therapeutic purposes.

High frequencies of nonviral colds and respiratory bacteria colonization among children in rural Western Uganda.

Introduction: Respiratory illness is the most common childhood disease globally, especially in developing countries. Previous studies have detected viruses in approximately 70-80% of respiratory illnesses. Methods: In a prospective cohort study of 234 young children (ages 3-11 years) and 30 adults (ages 22-51 years) in rural Western Uganda sampled monthly from May 2019 to August 2021, only 24.2% of nasopharyngeal swabs collected during symptomatic disease had viruses detectable by multiplex PCR diagnostics and metagenomic sequencing. In the remaining 75.8% of swabs from symptomatic participants, we measured detection rates of respiratory bacteria Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae by quantitative PCR. Results: 100% of children tested positive for at least one bacterial species. Detection rates were 87.2%, 96.8%, and 77.6% in children and 10.0%, 36.7%, and 13.3% for adults for H. influenzae, M. catarrhalis, and S. pneumoniae, respectively. In children, 20.8% and 70.4% were coinfected with two and three pathogens, respectively, and in adults 6.7% were coinfected with three pathogens but none were coinfected with two. Detection of any of the three pathogens was not associated with season or respiratory symptoms severity, although parsing detection status by symptoms was challenged by children experiencing symptoms in 80.3% of monthly samplings, whereas adults only reported symptoms 26.6% of the time. Pathobiont colonization in children in Western Uganda was significantly more frequent than in children living in high-income countries, including in a study of age-matched US children that utilized identical diagnostic methods. Detection rates were, however, comparable to rates in children living in other Sub-Saharan African countries. Discussion: Overall, our results demonstrate that nonviral colds contribute significantly to respiratory disease burden among children in rural Uganda and that high rates of respiratory pathobiont colonization may play a role. These conclusions have implications for respiratory health interventions in the area, such as increasing childhood immunization rates and decreasing air pollutant exposure.

Connecting unstably housed veterans living in rural areas to health care: Perspectives from Health Care Navigators.

OBJECTIVE: To understand existing care practices and policies, and potential enhancements, to improve the effectiveness of the US Department of Veterans Affairs (VA) Supportive Services for Veteran Families (SSVF) Health Care Navigators (HCN) in linking Veterans experiencing housing instability in rural areas with health care services. DATA SOURCES AND STUDY SETTING: We used primary data collected during semistructured interviews with HCNs (n = 21) serving rural areas across the United States during Spring 2022. STUDY DESIGN: We applied the Consolidated Framework for Implementation Research (CFIR) 2009 and the Social Ecological Model (SEM) to the collection and analysis of qualitative data to understand how HCNs administer services within SSVF and the larger community. DATA COLLECTION/EXTRACTION METHODS: We used rapid qualitative methods to summarize and analyze data. Templated matrix summaries identified facilitators and barriers to linking Veterans with health care services and policy and practice implications. PRINCIPAL FINDINGS: Using CFIR 2009, we identified contextual factors affecting successful implementation of HCN services within SSVF; we offer a crosswalk between CFIR 2009 and the version updated in 2022. Framing facilitators and barriers within the SEM provided insight into whether implementation strategies should be addressed at a community, interpersonal, or intrapersonal level within the SEM. Facilitators included sufficient knowledge, training, and mentorship opportunities for HCNs and their capacity to collaborate within their organization and with other community-based organizations. Barriers included lack of local technology and housing resources, inadequate understanding of Veterans' service eligibilities and pathways to access those services, and deficient collaboration with the VA. CONCLUSIONS: Understanding facilitators and barriers experienced by HCN when linking unstably housed Veterans in rural areas with health care services can inform future strategies, including policy changes such as increased training to support HCNs' understanding of eligibility, benefits, and entitlements as well as improving communication and collaboration between VA and community partners.

Eating Disorder Treatment Access in the United States: Perceived Inequities Among Treatment Seekers.

OBJECTIVE: Although eating disorders are associated with high rates of psychological and physical impairments and mortality, only about 20% of individuals with eating disorders receive treatment. No study has comprehensively assessed treatment access for those with these disorders in the United States. The authors examined access to eating disorder treatments and how it might vary among some populations. METHODS: Seekers of treatment for eating disorders (N=1,995) completed an online assessment of clinical demographic and anthropometric characteristics, barriers to eating disorder treatment access, and eating disorder symptomatology. Analyses were conducted to identify treatment access barriers, compare barriers to treatment access across demographic groups, and investigate relationships between barriers to treatment access and eating disorder symptoms. RESULTS: Financial barriers (e.g., lack of insurance coverage) were the most frequently reported barrier to treatment access. Participants with historically underrepresented identities and with a diagnosis of other specified feeding or eating disorder (OSFED) reported more barriers related to financial challenges, geographic location, eating disorder identification, sociocultural factors, and treatment quality compared with those with historically represented identities (e.g., White and cisgender persons). Higher frequencies of reported barriers to treatment access were associated with more severe eating disorder symptoms and poorer illness trajectories. CONCLUSIONS: Financial barriers were the most significant impediment to accessing treatment among individuals seeking eating disorder treatment. Barriers to treatment access disproportionally affected underrepresented groups and those with an OSFED diagnosis.

Common cold viruses circulating in children threaten wild chimpanzees through asymptomatic adult carriers.

Reverse zoonotic respiratory diseases threaten great apes across Sub-Saharan Africa. Studies of wild chimpanzees have identified the causative agents of most respiratory disease outbreaks as "common cold" paediatric human pathogens, but reverse zoonotic transmission pathways have remained unclear. Between May 2019 and August 2021, we conducted a prospective cohort study of 234 children aged 3-11 years in communities bordering Kibale National Park, Uganda, and 30 adults who were forest workers and regularly entered the park. We collected 2047 respiratory symptoms surveys to quantify clinical severity and simultaneously collected 1989 nasopharyngeal swabs approximately monthly for multiplex viral diagnostics. Throughout the course of the study, we also collected 445 faecal samples from 55 wild chimpanzees living nearby in Kibale in social groups that have experienced repeated, and sometimes lethal, epidemics of human-origin respiratory viral disease. We characterized respiratory pathogens in each cohort and examined statistical associations between PCR positivity for detected pathogens and potential risk factors. Children exhibited high incidence rates of respiratory infections, whereas incidence rates in adults were far lower. COVID-19 lockdown in 2020-2021 significantly decreased respiratory disease incidence in both people and chimpanzees. Human respiratory infections peaked in June and September, corresponding to when children returned to school. Rhinovirus, which caused a 2013 outbreak that killed 10% of chimpanzees in a Kibale community, was the most prevalent human pathogen throughout the study and the only pathogen present at each monthly sampling, even during COVID-19 lockdown. Rhinovirus was also most likely to be carried asymptomatically by adults. Although we did not detect human respiratory pathogens in the chimpanzees during the cohort study, we detected human metapneumovirus in two chimpanzees from a February 2023 outbreak that were genetically similar to viruses detected in study participants in 2019. Our data suggest that respiratory pathogens circulate in children and that adults become asymptomatically infected during high-transmission times of year. These asymptomatic adults may then unknowingly carry the pathogens into forest and infect chimpanzees. This conclusion, in turn, implies that intervention strategies based on respiratory symptoms in adults are unlikely to be effective for reducing reverse zoonotic transmission of respiratory viruses to chimpanzees.

Cytophagic histiocytic panniculitis leading to a diagnosis of acute myeloid leukemia with monocytic differentiation: A case report and literature review.

Cytophagic histiocytic panniculitis (CHP) is associated with a number of systemic conditions and is characterized by the presence of benign phagocytic histiocytes ("bean bag cells"), including phagocytosed erythrocytes, leukocytes, and platelets. We describe a case of a 72-year-old female who presented with a papular eruption that clinically mimicked pityriasis lichenoides et varioliformis acuta (PLEVA). Given that her skin biopsy had multiple features concerning PLEVA, this diagnosis was classified as a superficial pityriasis lichenoides-like variant of CHP. The histopathologic presence of cytophagic histiocytosis prompted workup for a systemic malignancy, leading to a diagnosis of underlying acute monocytic leukemia of myeloid lineage.

Constrictive physiology is not present in all dogs with idiopathic chylothorax.

OBJECTIVE: To determine whether subtotal pericardectomy affects recurrence and long-term outcomes in dogs with idiopathic chylothorax (IC). ANIMALS: 12 client-owned dogs diagnosed with IC between July 26, 2016, and March 23, 2023. METHODS: The diagnosis of constrictive physiology (CP) was established with cardiac catheterization and defined as elevated and equal diastolic pressures in all 4 cardiac chambers. Dogs were then entered into the constrictive physiology (CP) group or non-CP (NCP) group. All dogs received at least a thoracic duct ligation (TDL). The dogs in the CP group had a subtotal pericardectomy performed in addition to TDL. Repeated surgical interventions, recurrence, long-term outcomes, and survival times were recorded. RESULTS: 8 dogs were entered into the CP group and underwent TDL and subtotal pericardectomy. Four dogs were entered in the NCP group and underwent only a TDL. Four dogs in the CP group and 1 in the NCP group required multiple surgeries for recurrent chylothorax. The 1-, 2-, and 3-year disease-free rates were, respectively, 100%, 100%, and 50% for the NCP group and 87.5%, 72.9%, and 72.9% for the CP group (P = .935). The 1-, 2-, and 3-year survival rates were, respectively, 100%, 100%, and 100% for the NCP group and 87.5%, 72.9%, and 72.9% for the CP group (P = .317). CLINICAL RELEVANCE: Constrictive physiology should be evaluated by cardiac catheterization before surgical treatment of IC in dogs. If CP is not diagnosed, subtotal pericardectomy may not be required.

Platelet Function is Independent of Sphingolipid Manipulation.

INTRODUCTION: Previous literature suggests that sphingolipids may impact systemic coagulation and platelet aggregation, thus modulating the risks of thrombotic events. The goal of this investigation was to evaluate the role of serum sphingolipids on intrinsic platelet function to assess whether pharmacologic manipulation of sphingolipid metabolites would impact platelet aggregability. METHODS: C57BL/6J mice were injected with either normal saline, 1 mg/kg FTY720 (synthetic sphingosine-1-phosphate [S1P] receptor analog), or 5 mg/kg SLM6031434 (sphingosine kinase two inhibitor). Mice were sacrificed at 6 h and whole blood (WB) was collected for impedance aggregometry assessing platelet responsiveness to arachidonic acid or adenosine diphosphate. Ex vivo studies utilized WB or platelet-rich plasma that was pretreated with S1P, FTY720, amitriptyline, or d-sphingosine then analyzed by aggregability and flow cytometry for platelet and platelet-derived microvesicle characteristics. RESULTS: FTY720 and SLM6031434 pretreated induced similar arachidonic acid and adenosine diphosphate-mediated platelet aggregation as controls. Ex vivo WB and platelet-rich plasma treatment with S1P, FTY720, amitriptyline and d-sphingosine did not impact platelet aggregation. The percentages of CD41+, CD62P+ and CD41+/ceramide+, CD62P+/ceramide + platelets, and platelet-derived microvesicle were not significantly different between amitriptyline-treated and normal saline-treated cohorts. CONCLUSIONS: Sphingolipid modulating agents, such as FTY720, SLM6031434, S1P, amitriptyline, ceramide, and d-sphingosine do not appear to independently impact platelet aggregation in murine models.

Modulation of Paracellular Permeability in SARS-CoV-2 Blood-to-Brain Transcytosis.

SARS-CoV-2 primarily infects the lungs via the ACE2 receptor but also other organs including the kidneys, the gastrointestinal tract, the heart, and the skin. SARS-CoV-2 also infects the brain, but the hematogenous route of viral entry to the brain is still not fully characterized. Understanding how SARS-CoV-2 traverses the blood-brain barrier (BBB) as well as how it affects the molecular functions of the BBB are unclear. In this study, we investigated the roles of the receptors ACE2 and DPP4 in the SARS-CoV-2 infection of the discrete cellular components of a transwell BBB model comprising HUVECs, astrocytes, and pericytes. Our results demonstrate that direct infection on the BBB model does not modulate paracellular permeability. Also, our results show that SARS-CoV-2 utilizes clathrin and caveolin-mediated endocytosis to traverse the BBB, resulting in the direct infection of the brain side of the BBB model with a minimal endothelial infection. In conclusion, the BBB is susceptible to SARS-CoV-2 infection in multiple ways, including the direct infection of endothelium, astrocytes, and pericytes involving ACE2 and/or DPP4 and the blood-to-brain transcytosis, which is an event that does not require the presence of host receptors.

Alcohol-induced Golgiphagy is triggered by the downregulation of Golgi GTPase RAB3D.

The development of alcohol-associated liver disease (ALD) is associated with disorganized Golgi apparatus and accelerated phagophore formation. While Golgi membranes may contribute to phagophores, association between Golgi alterations and macroautophagy/autophagy remains unclear. GOLGA4/p230 (golgin A4), a dimeric Golgi matrix protein, participates in phagophore formation, but the underlying mechanism is elusive. Our prior research identified ethanol (EtOH)-induced Golgi scattering, disrupting intra-Golgi trafficking and depleting RAB3D GTPase from the trans-Golgi. Employing various techniques, we analyzed diverse cellular and animal models representing chronic and chronic/binge alcohol consumption. In trans-Golgi of non-treated hepatocytes, we found a triple complex formed between RAB3D, GOLGA4, and MYH10/NMIIB (myosin, heavy polypeptide 10, non-muscle). However, EtOH-induced RAB3D downregulation led to MYH10 segregation from the Golgi, accompanied by Golgi fragmentation and tethering of the MYH10 isoform, MYH9/NMIIA, to dispersed Golgi membranes. EtOH-activated autophagic flux is evident through increased WIPI2 recruitment to the Golgi, phagophore formation, enhanced LC3B lipidation, and reduced SQSTM1/p62. Although GOLGA4 dimerization and intra-Golgi localization are unaffected, loss of RAB3D leads to an extension of the cytoplasmic N terminal domain of GOLGA4, forming GOLGA4-positive phagophores. Autophagy inhibition by hydroxychloroquine (HCQ) prevents alcohol-mediated Golgi disorganization, restores distribution of ASGR (asialoglycoprotein receptor), and mitigates COL (collagen) deposition and steatosis. In contrast to short-term exposure to HCQ, extended co-treatment with both EtOH and HCQ results in the depletion of LC3B protein via proteasomal degradation. Thus, (a) RAB3D deficiency and GOLGA4 conformational changes are pivotal in MYH9-driven, EtOH-mediated Golgiphagy, and (b) HCQ treatment holds promise as a therapeutic approach for alcohol-induced liver injury.Abbreviation: ACTB: actin, beta; ALD: alcohol-associated liver disease; ASGR: asialoglycoprotein receptor; AV: autophagic vacuoles; EM: electron microscopy; ER: endoplasmic reticulum; EtOH: ethanol; HCQ: hydroxychloroquine; IP: immunoprecipitation; KD: knockdown; KO: knockout; MYH10/NMIIB: myosin, heavy polypeptide 10, non-muscle; MYH9/NMIIA: myosin, heavy polypeptide 9, non-muscle; PLA: proximity ligation assay; ORO: Oil Red O staining; PM: plasma membrane; TGN: trans-Golgi network; SIM: structured illumination super-resolution microscopy.

Direct red blood cell effect on thrombosis is dependent on the interaction of tissue factor and calcium with membrane phosphatidylserine.

BACKGROUND: Prior literature has implicated red blood cells (RBCs) in the initiation of thrombosis and suggests that posttransfusion hypercoagulability may occur secondary to the effects of RBCs. Elevated serum tissue factor is a known sequelae of acute trauma. Phosphatidylserine (PS) is a prothrombotic phospholipid present within the RBC cell membrane. We hypothesized that RBC aggregation is dependent on the interaction between RBC membrane bound (exposed) PS, extracellular calcium, and tissue factor. METHODS: Human whole blood (WB) was separated into components, including RBCs and platelet-rich plasma (PRP). Whole blood, PRP, and RBCs underwent impedance aggregometry utilizing arachidonic acid (AA), ADP, collagen, calcium, and tissue factor (TF)-based agonists. Red blood cells then underwent impedance aggregometry utilizing combined calcium and TF agonists. Red blood cells were pretreated with Annexin V, a known PS blocking agent, and underwent impedance aggregometry with combined calcium and TF agonists to determine if the mechanism of calcium/TF-induced RBC aggregability is dependent on PS. Red blood cells treated with calcium, TF, calcium+TF, and pre-treated with Annexin V followed by calcium+TF were perfused through an in vitro model of pulmonary microcirculatory flow. RESULTS: Red blood cell aggregation was significantly higher than that of WB and PRP when utilizing a TF agonist, an effect unique to TF. The combination of calcium and TF demonstrated significantly higher RBC aggregation than either agonist alone. Pretreatment with Annexin V resulted in a significantly reduced aggregability of RBC following treatment with TF + calcium. Red blood cells aged to 42 days did not exhibit significant change in aggregation. Exposure to calcium and TF significantly reduced time to thrombosis of RBCs perfused through a pulmonary microcirculatory model. CONCLUSION: Treatment with both TF and calcium synergistically induces RBC aggregation. Phosphatidylserine appears to play an integral role in the TF/calcium-based, age-independent RBC aggregation response. Red blood cells treated with TF + calcium exhibit more rapid thrombus formation in an in vitro model of pulmonary microcirculatory perfusion.

Advances in understanding and exploiting Siglec-glycan interactions.

Sialic-acid-binding immunoglobulin-type lectins (Siglecs) are a family of cell-surface immunomodulatory receptors that recognize sialic-acid-containing glycans. The majority of Siglecs have an inhibitory motif in their intercellular domain and can regulate the cellular activation of immune cells. Importantly, the immunomodulatory role of Siglecs is regulated by engagement with distinct sialoglycan ligands. However, there are still many unanswered questions about the precise ligand(s) recognized by individual Siglec family members. New tools and approaches to study Siglec-ligand interactions are rapidly filling this knowledge gap. This review provides an overview of recent advances in discovering Siglec ligands as well as the development of approaches to modulate the function of Siglecs. In both aspects, chemical biology approaches are emphasized with a discussion on how these are complementing biochemical and genetic strategies.

Does Terminology Matter When Measuring Stigmatizing Attitudes About Weight? Validation of a Modified Attitudes Toward Obese Persons Scale.

Commonly used medical terms like "obesity" and "overweight" have been identified as stigmatizing. Thus, this study sought to revise a commonly used measure of weight stigmatizing attitudes, the Attitudes Toward Obese Persons (ATOP) scale. We compared the original terminology in the ATOP (e.g., "obese")to a Modified version using neutral terms (e.g., "higher weight"). We randomized participants (N = 599) to either receive the original or Modified ATOP and compared their scores. There was no significant difference between the scores of participants who received the original ATOP and the Modified ATOP, t(597) = -2.46, p = .550. Through principal component analysis, we found the Modified ATOP is best used as a 13-item unidimensional measure. Findings suggest a Modified version of the ATOP with neutral language is suitable for assessing negative attitudes about higher-weight people without sacrificing psychometric properties. Further examination of the terminology used in weight stigma measures is needed to determine how to best assess weight stigma without reinforcing stigmatizing attitudes. The findings of the present study suggest that the use of neutral terms in measures of anti-fat bias is a promising solution that warrants further investigation.