University of Valparaíso

• Median nerve variants within the carpal tunnel have a pooled prevalence of 12%. • Bifid median nerve is the most frequently reported morphological variant. • No consistent association was found between anatomical variants and carpal tunnel syndrome. • Coexisting vascular or muscular anomalies may influence surgical complexity. • Preoperative imaging may aid anatomical identification, although clinical benefit remains uncertain. Anatomical variants of the median nerve (MN) within the carpal tunnel are clinically relevant due to their potential impact on the development, diagnosis, and surgical management of carpal tunnel syndrome (CTS). Reported prevalence estimates vary considerably across populations and study designs. To systematically review the literature and estimate the pooled prevalence of morphological variants of the median nerve within the carpal tunnel, and to assess their laterality, geographic distribution, and reported clinical implications. A systematic review and meta-analysis were conducted in accordance with PRISMA 2020 guidelines. MEDLINE, Scopus, Web of Science, CINAHL, and LILACS were searched from inception to November 2024. Google Scholar was used for supplementary screening of gray literature. Observational studies reporting the prevalence of MN variants identified through imaging, surgical exploration, or anatomical dissection were included. Methodological quality was assessed using the Anatomical Quality Assessment (AQUA) tool. Pooled prevalence estimates were calculated using a random-effects model (DerSimonian–Laird) with Freeman–Tukey double arcsine transformation. Sixty-three studies met eligibility criteria for qualitative synthesis, and 19 studies (n = 9,045 subjects) were included in the primary meta-analysis. The pooled prevalence of MN variants within the carpal tunnel was 12% (95% CI: 9–15%), with substantial heterogeneity (I² = 87%). Subgroup analysis showed similar prevalence in imaging-based studies (12%, 95% CI: 9–15%; I² = 87.8%). No clear laterality predominance was observed (right: 46%, 95% CI: 40–52%; I² = 0.0%; left: 53%, 95% CI: 48–59%; I² = 0.0%), whereas bilateral presentation demonstrated greater variability (21%, 95% CI: 6–36%; I² = 90.6%). Geographic subgroup analysis showed pooled prevalence estimates of 22% in Asia (95% CI: 13–31%; I² = 92.6%), 20% in Europe (95% CI: 14–27%; I² = 79.2%), and 18% in America (95% CI: 16–20%; I² = 19.4%). Morphological variants of the median nerve within the carpal tunnel are relatively common anatomical findings. Current evidence does not support their role as independent risk factors for CTS; however, their coexistence with vascular or muscular anomalies may influence local anatomical relationships and surgical complexity. Preoperative imaging may facilitate anatomical identification and surgical planning, although its impact on clinical outcomes and intraoperative complications remains uncertain and requires further prospective investigation.

The aim of this paper is to show the existence and uniqueness for the solution to a stochastic differential equation driven by fractional Brownian motion with Hurst parameter H<1∕2, with a discontinuous diffusion coefficient. The stochastic integral used in this paper is an extension of the Stratonovich integral introduced by León (Bernoulli 26 (2020) 2436–2462). In this way, we are able to complement previous results for SDEs driven by fBms with H>1∕2.

Ullucus tuberosus is an underutilized Andean tuber of South America, representing a highly nutritious food source valuable in bioactive compounds and used in traditional medicine by the local population. Despite its potential as a functional food, limited information is available regarding the phenolic composition of its diverse varieties, hindering its revalorization and potential biotechnological applications. In this study, the total phenolic content (TPC), antioxidant activity (AA), and thirteen individual phenolic compounds were investigated in five ulluco varieties using UV-Vis spectrophotometry and ultra-high-performance liquid chromatography, coupled with electrospray ionization and a triple quadrupole mass spectrometer (UHPLC-ESI-MS/MS). Statistical analyses revealed significant differences (p < 0.05) among the varieties in TPC, AA, and the concentration of the four quantified flavonoids. The major flavonoids found were rutin, quercetin-3-glucoside, kaempferol-3-rutinoside, and isorhamnetin-3-rutinoside, using solid-phase extraction (SPE-C8) as a cleanup step for ultrasound-assisted extracts, achieving satisfactory precision and recovery. Principal Component Analysis (PCA) effectively discriminated the samples based on their phenolic profiles, AA, and TPC. These findings contribute to the revalorization of ulluco varieties by providing new insights into their phenolic composition and demonstrating their potential as a source of health-promoting bioactive compounds.

Although metacognitive training (MCT) and cognitive-behavioural therapy (CBT) have been proven to be effective interventions for the treatment of symptoms of schizophrenia, still little is known about the effects on quality of life (QoL). This systematic review compares the effectiveness of MCT and CBT-based interventions for QoL in individuals with schizophrenia spectrum disorders (SSD). Three electronic databases were screened up to October 2025 for MCT and CBT studies reporting QoL outcomes for patients diagnosed with SSD. Data from 38 randomized controlled trials (RCTs) met the inclusion criteria, of which eight MCT and 30 studies included CBT-based interventions. When comparing MCT against control interventions, none of the eight MCT studies found significant differences in the overall score of QoL scales at posttest and at 1- or 6-month follow-up. Only one study has assessed the effects of MCT after 3 years, yet it demonstrated significant improvements in QoL. For CBT-based interventions, nine of 26 available between-group comparisons in overall QoL showed a significant improvement in QoL after CBT at the posttest, and five of 19 effects were observed at follow-up. This review provides modest evidence for improvements in QoL from CBT-based interventions and a small number of studies concerning QoL in MCT, emphasizing the need for further research that prioritizes QoL as a primary outcome as well as the need for research with longer follow-ups to capture the delayed effects of MCT and CBT on QoL. It awaits to be tested whether the recent extension of MCT (app, 2 modules on self-esteem and stigma) augments QoL.

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Abstract. Atmospheric blocking is a key driver of persistent circulation anomalies and associated extreme events in the Southern Hemisphere, yet its characteristics around Antarctica remain poorly understood due to methodological diversity and the absence of a consolidated, long-term dataset. This study presents a new multi-method Antarctic atmospheric blocking dataset covering the period 1979–2024, derived from ERA5 reanalysis and constructed using multiple blocking detection approaches applied consistently across the Southern Hemisphere (25° S–90° S). The dataset integrates diagnostics based on 500 hPa geopotential height and vertically integrated potential vorticity within a unified framework for spatial filtering, event definition, and temporal tracking. It provides instantaneous blocking masks, spatiotemporally tracked event catalogues, time series, and aggregated climatologies that are directly comparable across methods. The results reveal only weak large-scale similarities in Antarctic blocking across detection approaches, mainly related to high latitude occurrence and seasonal modulation. In contrast, pronounced method dependent diversity is evident in blocking frequency, spatial extent, the number of detected blocking events, and persistence. Geopotential height-based methods identify a broader spectrum of anticyclonic flow regimes, including events extending into the Antarctic interior, whereas potential vorticity-based methods isolate fewer, more spatially confined events that emphasize dynamically coherent upper-level disturbances near the polar vortex. Event-based diagnostics further reveal systematic trade-offs between event frequency and duration, illustrating how different methodological choices preferentially capture either shorter-lived circulation anomalies or more persistent blocking structures. These contrasts arise from the diverse dynamical expressions of blocking at high southern latitudes, indicating that no single diagnostic fully captures Antarctic blocking behavior. Key uncertainties relate to threshold sensitivity, spatial filtering, and diagnostic formulation, which should be considered when interpreting blocking statistics and inter-method differences. By providing a consistent and openly accessible resource, this dataset allows direct intercomparison of blocking definitions, supports evaluation of climate models over Antarctica, and provides a foundation for future studies of blocking-related circulation variability and extreme events.

Angiogenesis depends on Ca2+-mediated endothelial cell migration. The increase in intracellular Ca2+ concentration ([Ca2+]i) is coordinated by caveolae and the Cx43 hemichannel opening. However, the functional coupling of voltage-dependent Na+ channels (Nav) with Na+-Ca2+ exchanger reverse mode (NCXrm) activation may contribute to the response, which was evaluated using the wound-healing assay in primary cultures of rat mesenteric endothelial cells. Changes in [Ca2+]i, the hemichannel opening and the association of Nav channels with caveolin-1, a caveolae structural protein, were analyzed. Both endothelial cell migration and the associated Ca2+ signaling were inhibited by tetrodotoxin (TTX), a Nav channel blocker, lamotrigine, a preferential Nav1.2 inhibitor, or 4,9-anhydro-TTX, a specific Nav1.6 blocker. A similar result was found by disrupting caveolae organization with methyl-β-cyclodextrin or blocking NCXrm with SEA0400. TTX and SEA0400 also prevented Cx43 hemichannel opening, and tubular-like structure formation depended on Nav channels. An analysis using a proximity ligation assay showed that endothelial cell migration was paralleled by the progressive association of caveolin-1 with Nav1.2, but not Nav1.6, channels. These results suggest that the functional coupling of Nav1.2 and Nav1.6 channels with the activation of NCXrm and Cx43 hemichannels mediates the Ca2+ signaling associated with endothelial cell migration and angiogenesis, which provides new targets to modulate angiogenesis in physiological or pathological conditions.

Plasma biomarkers have emerged as robust indicators of Alzheimer's disease (AD) pathology, offering accessible tools for staging and stratification. However, their expression across globally diverse populations remains poorly characterized. The aim of this study was to evaluate whether the combination of plasma biomarkers could distinguish different stages along the AD continuum and assess their clinical associations in a Latin American cohort. We evaluated plasma amyloid, tau, and neurodegeneration (ATN) biomarkers in 318 older adults from a Chilean community- and clinic-based cohort, including individuals with subjective cognitive complaints (SCC), mild cognitive impairment (MCI), and Alzheimer's disease dementia (ADD), alongside cognitively unimpaired (CU) participants. Plasma ATN biomarkers (Aβ42/Aβ40, p-tau217, NfL, and GFAP) were quantified using Simoa technology. Global cognition was assessed with the Addenbrooke's Cognitive Examination (ACE), memory with the Free and Cued Selective Reminding Test (FCSRT), and functional ability with the Technology-Activities of Daily Living Questionnaire (T-ADLQ). Group differences in plasma biomarkers were examined using ANCOVA models adjusted for age, sex, and education, and associations with cognitive performance were evaluated through linear regression analyses. In addition, supervised machine-learning models were implemented to classify participants across diagnostic categories based on plasma biomarker profiles, using cross-validation to evaluate predictive performance. We observed a progressive decline in the Aβ42/Aβ40 ratio and elevations in p-tau217 and GFAP across the clinical continuum. Additionally, p-tau217 and NfL levels were inversely associated with cognitive, memory, and functional performance. Notably, p-tau217 distinguished ADD from CU with high accuracy (AUC = 0.88), although its performance in earlier stages was limited. These findings support the biological consistency of plasma biomarkers in AD-related neurodegeneration and provide novel evidence from a Latin American population. Further studies are needed to improve early-stage detection and to better understand how genetic, environmental, and health factors shape biomarker expressions in underrepresented regions.

Serotonin (5-HT) plays an important role in shaping brain network dynamics by regulating excitatory synaptic function and neuronal excitability. However, much less is known about how 5-HT tunes synaptic inhibition. Here, we demonstrate that transient 5-HT signaling persistently suppresses GABAergic synapses onto layer 2/3 pyramidal neurons in the medial prefrontal cortex (mPFC). Moreover, we found that 5-HT1A and 5-HT2A receptors differentially contribute to 5-HT regulation of synaptic inhibition, possibly by acting at distinct GABAergic cell subpopulations. Importantly, 5-HT2A receptor activation triggers retrograde endocannabinoid signaling to reduce GABA release selectively at synapses formed by somatostatin (SST+)- but not parvalbumin (PV+)-positive GABAergic interneurons. Altogether, our results highlight the diverse molecular and cell-type-specific mechanisms by which 5-HT signaling modulates inhibitory circuits to shape cortical function.