UC San Diego

The burden of cirrhosis and chronic liver disease is growing, yet there is a projected worsening deficit in hepatology providers. As such, cirrhosis and liver disease have been important inclusions within the core curricula of Internal Medicine. Formal assessments of provider preparedness resulting from the curriculum are lacking though. Prior studies have demonstrated that exposure to cirrhosis in undergraduate medical education is insufficient, as are learner comfort and self-reported knowledge levels. These findings are further corroborated by a multicenter survey of incoming Internal Medicine interns showing that subjective comfort with and objective knowledge of various liver disease topics are lacking compared to other common Internal Medicine topics. This paper also demonstrates how similar surveys may be used to identify additional topics that may require adjustments for curricular improvement.

RATIONALE: Stable isotope analysis of growth layer groups (GLGs) in mammal dentin is an increasingly prevalent and noninvasive approach to study animal foraging ecology. However, empirical evidence to support assumed proper methodologies for sampling GLGs is lacking. Here, we examine the effects of intratooth and intertooth variations with respect to targeted GLGs, as well as the effects of common pretreatments (e.g., formic acid and graphite) to enhance GLG visibility, on stable isotope values (δ13C and δ15N) from dentin. METHODS: We measured the δ13C and δ15N values of killer whale (Orcinus orca) dentin. We used dentin from 37 teeth to compare stable carbon (δ13C) and nitrogen (δ15N) isotope values from multiple locations within a GLG (intratooth variation), from corresponding GLGs among teeth of an individual (intertooth variation), and from treated and untreated teeth. RESULTS: We observed no significant differences in the δ13C or δ15N values when sampling a single GLG from multiple locations (intratooth variation) or when comparing the same GLG across duplicate teeth of individuals (intertooth variation). One tooth in a triplicate set showed a significantly different but likely biologically inconsequential δ13C value. Lastly, formic acid and graphite highlighting to accentuate GLGs did not significantly influence measured stable isotope values. CONCLUSIONS: We validate several previous assumptions in this field of study. First, dentin samples for stable isotope analysis can be sampled from different locations across a GLG. Second, researchers can compare stable isotope values from the same GLGs of different teeth collected from the same individual in most cases, as the δ13C and δ15N values did not vary with the sampled tooth. Third, a common protocol of formic acid and graphite treatment to enhance GLG visibility does not bias the δ13C and δ15N values from dentin. We also describe factors to consider and cautions associated with these conclusions.

This study compared the processing of non-binary morphemes in Spanish (e.g., todxs, todes) with the processing of canonical grammatical gender violations in Spanish pronouns (e.g., Los maestros… todas…). Using self-paced reading, the study examined how individual differences in working memory and gender/sex diversity beliefs affected language processing at three regions of interest (ROI): the pronoun, the pronoun +1, and the pronoun +2. Seventy-eight Spanish-English bilinguals completed two self-paced reading tasks, one with non-binary pronouns and another with grammatical gender violations, as well as a working memory task, a language dominance questionnaire, and a gender/sex diversity beliefs questionnaire. Processing costs were operationalized as longer reaction times (RTs) or inaccurate responses. Results showed overall processing costs for non-binary morphemes at all 3 ROIs, but no processing costs were observed in terms of accuracy or response times to the comprehension question. The results suggest that processing non-binary pronouns results in a small processing cost that does not affect overall sentence comprehension. The small observed processing cost was moderated by gender/sex diversity beliefs, with gender normative beliefs increasing RTs at the pronoun and affirmation of diverse gender identities beliefs reducing the RTs at the second spillover region. In contrast, grammatical gender violations only showed a processing cost at the first spillover region and were not moderated by working memory nor gender/sex diversity beliefs. Taken together, the results suggest that non-binary pronouns are processed differently than grammatical gender violations and that the small processing cost they impose can lead to good enough comprehension.

OBJECTIVES: Tools are needed to evaluate the risk of developing Parkinson disease (PD) in at-risk populations. In this study, we examine differences in alpha-synuclein seed amplification assay (αSyn-SAA) qualitative results and amplification parameters between nonmanifesting carriers (NMCs) of PD-related pathogenic variants, prodromal PD, and PD and the risk of developing a synucleinopathy in participants with prodromal PD. METHODS: Cross-sectional and longitudinal CSF αSyn-SAA results from participants in the Parkinsons Progression Markers Initiative were analyzed. αSyn-SAA positivity and amplification parameters (maximum fluorescence [Fmax], time-to-threshold [TTT], time-to-50% Fmax [T50], and area under the curve [AUC]) were compared between NMCs, participants with prodromal PD, and participants with PD, and their relationship with the likelihood of phenoconversion in participants with prodromal PD was investigated. RESULTS: Samples from 1,027 participants were analyzed (159 healthy controls [HCs], 247 NMCs, 96 participants with prodromal PD, and 525 participants with PD). TTT and T50 were faster, and AUC was higher in αSyn-SAA+ participants with prodromal PD and PD than αSyn-SAA+ NMCs and HC participants (Kruskal-Wallis χ2 = 4.15-13.96, p < 0.0002-0.04). Participants with prodromal PD with positive αSyn-SAA tests and faster TTT had higher rates of phenoconversion (log-rank p = 0.001 and log-rank test-for-trend p < 0.0001). There were no changes in 48 participants with prodromal PD with longitudinal assays. DISCUSSION: αSyn-SAA positivity and faster seed amplification are associated with a greater risk of developing PD in at-risk individuals and may aid in predicting phenoconversion.

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Large multiprotein machines are central to many biological processes. However, stoichiometric determination of protein complex subunits in their native states presents a significant challenge. This study addresses the limitations of current tools in accuracy and precision by introducing concatemer-assisted stoichiometry analysis (CASA). CASA leverages stable isotope-labeled concatemers and liquid chromatography-parallel reaction monitoring-mass spectrometry (LC-PRM-MS) to achieve robust quantification of proteins with sub-femtomole sensitivity. As a proof of concept, CASA was applied to study budding yeast kinetochores. Stoichiometries were determined for ex vivo reconstituted kinetochore components, including the canonical H3 nucleosomes, centromeric (Cse4^CENP-A) nucleosomes, centromere proximal factors (Cbf1 and CBF3 complex), inner kinetochore proteins (Mif2^CENP-C, Ctf19^CCAN complex), and outer kinetochore proteins (KMN network). Absolute quantification by CASA revealed Cse4^CENP-A as a cell cycle-controlled limiting factor for kinetochore assembly. These findings demonstrate that CASA is applicable for stoichiometry analysis of multiprotein assemblies.

BACKGROUND AND AIMS: Elevated lipoprotein(a) [Lp(a)], high-sensitivity C-Reactive Protein (hs-CRP), and total homocysteine (tHcy) are associated with atherosclerotic cardiovascular disease (ASCVD) risk. This study investigated the individual and joint associations of Lp(a), hs-CRP and tHcy with coronary heart disease (CHD) and stroke. METHODS: This study was conducted in the Multi-Ethnic Study of Atherosclerosis (MESA) cohort (2000-2017) (CHD analytic N = 6,676; stroke analytic N = 6,674 men and women). Associations between Lp(a) (<50 vs. ≥50 mg/dL), hs-CRP (<2 vs. ≥2 mg/L) and tHcy (<12 vs. ≥12 µmol/L) and CHD and stroke incidence were evaluated individually and jointly using Cox proportional hazards regression. RESULTS: Individually, elevated tHcy was associated with CHD and stroke incidence, Lp(a) with CHD only and hs-CRP with stroke only. In combined analyses, CHD risk was higher when multiple biomarkers were elevated [hs-CRP+Lp(a), hazard ratio (HR)=1.39, 95 % confidence interval (CI): 1.06, 1.82; hs-CRP+ tHcy, HR = 1.34, 95 % CI: 1.02, 1.75; Lp(a)+ tHcy HR = 1.58, 95 % CI: 1.08, 2.30; hs-CRP+Lp(a)+ tHcy HR = 2.02, 95 % CI: 1.26, 3.24]. Stroke risk was elevated when hs-CRP and either Lp(a) (HR = 1.51, 95 % CI: 1.02, 2.23) or tHcy (HR = 2.10, 95 % CI: 1.44, 3.06) was also high, when all three biomarkers were elevated (HR = 2.99, 95 % CI: 1.61, 5.58), or when hs-CRP and tHcy (HR = 1.79, 95 % CI: 1.16, 2.76) were both high. CONCLUSIONS: Risk of ASCVD was highest with concomitant elevation of tHcy, hs-CRP and Lp(a). Inclusion of tHcy and consideration of biomarker combination rather than individual biomarker levels may help better identify individuals at greatest risk for ASCVD events.