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Age-related neurodegenerative disorders like Alzheimer's disease (AD) and Parkinson's disease (PD) are characterized by deposits of protein aggregates, or amyloid, in various regions of the brain. Historically, aggregation of a single protein was observed to be correlated with these different pathologies: tau in AD and α-synuclein (αS) in PD. However, there is increasing evidence that the pathologies of these two diseases overlap, and the individual proteins may even promote each other's aggregation. Both tau and αS are intrinsically disordered proteins (IDPs), lacking stable secondary and tertiary structure under physiological conditions. In this study we used a combination of biochemical and biophysical techniques to interrogate the interaction of tau with both soluble and fibrillar αS. Fluorescence correlation spectroscopy (FCS) was used to assess the interactions of specific domains of fluorescently labeled tau with full length and C-terminally truncated αS in both monomer and fibrillar forms. We found that full-length tau as well as individual tau domains interact with monomer αS weakly, but this interaction is much more pronounced with αS aggregates. αS aggregates also mildly slow the rate of tau aggregation, although not the final degree of aggregation. Our findings suggest that co-occurrence of tau and αS in disease are more likely to occur through monomer-fiber binding interactions, rather than monomer-monomer or co-aggregation. [ABSTRACT FROM AUTHOR]

Introduction: In 2023, a group of experts proposed that a definition of major bleeding in pharmaceutically anticoagulated patients be used in all snakebite trials. This includes bleeding that results in death, is life-threatening, causes chronic sequelae, or consumes major healthcare resources, including bleeding into a major area or hemoglobin concentration decrease ≥20 g/L. We hypothesized that a decline in hemoglobin concentration ≥20 g/L is common but rarely clinically significant in our population of Arizona rattlesnake bite patients. Methods: Poison center records of rattlesnake bites in humans from 2018 through 2022 were retrospectively reviewed and assessed for major bleeding by the above criteria. Results: Four hundred and eighty-one patients met the inclusion criteria, of whom 265 (55.1%) had a hemoglobin concentration decrease ≥20 g/L. No patients died, and there was no evidence of bleeding into a critical organ. Three patients (1.1%) received blood transfusions. A decrease in hemoglobin concentration ≥20 g/L was 100% sensitive for identifying the major bleeding-associated outcomes; however, specificity was only 45.2%. Measures of healthcare utilization and chronic sequelae were somewhat higher in patients with a decrease in hemoglobin concentration ≥20 g/L. Discussion: Laboratory manifestations of hemotoxicity were common in this population, but hemorrhage was rare. While over half of patients met the major bleeding criterion of a decline in hemoglobin concentration ≥20 g/L, only 1.1% had bleeding that was potentially life-threatening as measured by receipt of a red blood cell transfusion. None died or had bleeding into a critical area. While nonspecific for major bleeding, a drop in hemoglobin concentration correlated with worse envenomation severity: these patients received more vials of antivenom, had a higher medical bill, a longer hospital stay, and were less likely to report full recovery at 90 days. Conclusions: A decrease in hemoglobin concentration ≥20 g/L should not be used as evidence of major bleeding for Arizona rattlesnake envenomation studies, but it may have a role as an indirect marker of envenomation severity. [ABSTRACT FROM AUTHOR]

Introduction: Rattlesnake (Crotalus spp., Sistrurus spp.) bites in the southwestern United States are associated with significant morbidity. This study aims to describe 25 years of rattlesnake encounters reported to the Arizona Poison and Drug Information Center to identify vulnerable populations and circumstances where encounters occur to create public education to reduce future bites. Methods: Cases of suspected rattlesnake encounters in Arizona reported to the Arizona Poison and Drug Information Center between 1999 and 2023 were analyzed to identify populations and circumstances associated with encounters. Results: A total of 3,808 cases were analyzed overall and by age subgroups. Most encounters occurred in men (69.9%), during the evening (16:00–21:59; 49.2%), in summer (41.9%), and close to home (38.2%). Most bites occurred to the lower extremity (51%). Children 0 to 12-years-old have more encounters than those 13-years-old and older in rural zip codes (27.7% versus 14.8%; P = 0.005), during spring (31.8% versus 22.3%; P = 0.0005), and during the evening (64.4% versus 48.1%; P < 0.001). Discussion: Rattlesnakes are encountered when rattlesnake and human behavior patterns overlap. Many people spend time outside during evening hours in the summer, and valuable resources like food, water, and shelter can be found near houses where humans spend much of their time. Most age groups have similar encounter circumstances but encounters among children 0 to 12-years-old differ in time of day, season, and urbanization level than encounters of those 13-years-old and older. Limitations of this study include underreporting of encounters, incomplete case details, potential reporting bias, potential snake misidentification, and geographic coverage of the poison center. Conclusion: Prevention of rattlesnake bites by reducing encounters is the most effective way to reduce suffering and healthcare costs. Future steps include creating and disseminating targeted public health education using the data collected. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine worsening of OCD symptoms after childbirth in individuals seeking assessment or treatment of OCD. The postpartum period may make parents biologically and psychologically vulnerable to OCD symptoms. Participants included 222 parents with OCD who completed surveys through a self-help website. Most women and almost half of men with self-reported OCD reported an increase in OCD symptoms following childbirth. Retrospective report of perceived worsening of OCD symptoms after childbirth was associated with more aggressive obsessions for both men and women, in comparison to individuals whose OCD symptoms did not worsen around childbirth. Women whose OCD symptoms worsened after childbirth reported more impairment in social functioning than individuals whose symptoms did not worsen. These results highlight the need to develop a better understanding of aggressive obsessions in parents, and improve education about prevalence, content, assessment, and intervention for aggression-focused intrusive thoughts. [ABSTRACT FROM AUTHOR]

Ion-interaction chromatography utilizes the addition of amphiphilic (surfactant) molecules to the mobile-phase solution in order to bring about the retention and separation of hydrophilic ionic analytes on reversed-phase liquid chromatographic stationary phases. The mechanism by which retention and separation in ion-interaction chromatagraphy is accomplished remains unclear, although two primary mechanisms of this phenomenon have been proposed: preadsorption of the hydrophobic counterions to the hydrophobic stationary phase followed by interaction with the ionic analyte or adsorption of ion-paired species to the hydmphobic surface. There is evidence that both mechanisms contribute to ionic retention and separations. In this work, ion interactions at a [C.sub.18] stationary-phase interface are investigated by confocal Raman microscopy of individual stationary-phase particles, which is capable of quantifying surface concentrations of surfactants and model solutes. Raman spectra taken within the interior of the particle indicate that preadsorption of the hydrophobic surfactant cetylpyridinium to the stationary-phase interface is sensitive to ionic strength and concentration of organic modifier in the mobile phase. It was also determined that the presence of low concentrations of a model, ionic solute, nitrobenzenesulfonate, leads to greater adsorption of cetylpyridinium ion at the hydrophobic interface. As the concentration of nitrobenzenesulfonate is increased, the 1:1 increase in the cetylpyridinium ion interfacial concentration provides evidence of ion pairs forming at the stationary-phase surface. 10.1021/ac100781p

Wetting phenomena in reversed-phase liquid chromatographic (RPLC) stationary phase particles strongly influ. ence the retention of solutes with high water-content mobile phases. To better understand these phenomena, this work reports the spectroscopic observation of the wetting of the interior of individual [C.sub.18]-silica stationary phase particles with acetonitrile-water mobile phase solutions by confocal Raman microscopy. It was found that the pores of dry [C.sub.18] silica do not wet when the concentration of acetonitrile is below O. 12 mol fraction (28% by volume). It was also found that there is a wetting hysteresis, where particles that had been previously exposed to aeetonitrile solutions above the wetting transition remain filled with solution even at much lower concentrations of acetonitrile in the surrounding solution. Contact angles of acetonitrile-water solutions were measured at a planar [C.sub.18]-modified silica surface and used to predict the capillary wetting of the particles based on the Young-Laplace equation. The solution composition at the wetting transition detected by Raman microscopy is higher in acetonitrile concentration than predicted by the Young-Laplace equation, which may be due to the presence of a vapor or air gap at the interface between the hydrophobic pores and aqueous solution. Further evidence of this behavior is found in water porosimetry results, which show wetting pressures ~5 times greater than predicted by the Young-Laplace equation and are consistent with only 50% of a water interface being in contact with the [C.sub.18] surface. This fraction increases to 80% at an acetenitrile concentration of 0.12 mol fraction, leading to spontaneous and irreversible wetting of the hydrophobic pores.

The influence of organic modifiers on the structure of reversed-phase liquid chromatographic (RPLC) stationary phases has been a topic of considerable investigation. Retention of organic modifiers in the stationary phase has previously been determined by chromatographic measurements, and the polarity and heterogeneity of the resulting solvation environment has been studied using solvatochromic, fluorescent, and spin probes. In the present work, the composition and solvation environment of a stationary phase is investigated using confocal Raman microscopy, which allows the in situ examination of the solvation environment within individual chromatographic stationary phase particles without the use of probe molecules. The accumulation of organic modifiers in the stationary phase can be quantified, and the environment of the modifier in the stationary phase can be determined. Specifically, we have investigated the interactions of acetonitrile with [C.sub.18]-functionalized silica particles using confocal Raman microscopy, which enables the sampling of small (~1 fL) volumes within individual 10 [micro]m particles. Bare chromatographic silica was also studied in order to investigate the interactions of acetonitrile with surface silanols. The nitrile-stretching ([v.sub.CN]) frequency of acetouitrile responds sensitively to the dipolarity of its local microenvironment. The populations of solution-phase and interfacial acetonitrile are thus spectroscopically distinguishable. Scattering from [v.sub.CN] shows contributions from three different environments within a single RPLC chromatographic particle: acetonitrile in the interparficle mobile phase, [C.sub.18]-chain associated acetonitrile, and acetonitrile that is interacting with residual surface silanols. Data are presented quantifying these populations and characterizing their environments within single stationary phase particles.

We examined whether a history of self-reported childhood sexual abuse (CSA) moderates the relationship between obesity and mental health symptoms (depression, anxiety, and posttraumatic stress disorder) in an ethnically diverse sample of low-income women. A community sample of 186 women completed self-report measures and had their weight and height measured. Body mass index and CSA had an interactive effect on all mental health measures, such that obese women with a CSA history reported substantially higher levels of all symptoms. These results give greater specificity to the obesity–mental health link reported in previous studies and provide possible directions for targeted intervention. [ABSTRACT FROM AUTHOR]