Search

Our sense of hearing is mediated by cochlear hair cells, localized within the sensory epithelium called the organ of Corti. There are two types of hair cells in the cochlea, which are organized in one row of inner hair cells and three rows of outer hair cells. Each cochlea contains a few thousands of hair cells, and their survival is essential for our perception of sound because they are terminally differentiated and do not regenerate after insult. It is often desirable in hearing research to quantify the number of hair cells within cochlear samples, in both pathological conditions, and in response to treatment. However, the sheer number of cells along the cochlea makes manual quantification impractical. Machine learning can be used to overcome this challenge by automating the quantification process but requires a vast and diverse dataset for effective training. In this study, we present a large collection of annotated cochlear hair-cell datasets, labeled with commonly used hair-cell markers and imaged using various fluorescence microscopy techniques. The collection includes samples from mouse, human, pig and guinea pig cochlear tissue, from normal conditions and following in-vivo and in-vitro ototoxic drug application. The dataset includes over 90,000 hair cells, all of which have been manually identified and annotated as one of two cell types: inner hair cells and outer hair cells. This dataset is the result of a collaborative effort from multiple laboratories and has been carefully curated to represent a variety of imaging techniques. With suggested usage parameters and a well-described annotation procedure, this collection can facilitate the development of generalizable cochlear hair cell detection models or serve as a starting point for fine-tuning models for other analysis tasks. By providing this dataset, we aim to supply other groups within the hearing research community with the opportunity to develop their own tools with which to analyze cochlear imaging data more fully, accurately, and with greater ease.

The aim of this paper is to analyse the students' performance in the mathematical competency aspect of the Programme for International Student Assessment (PISA) 2015 tests and to compare 5 Spanish regions in this respect -- Navarra, Castile-León and Catalonia, with results above the national average; and Extremadura and Andalusia, with results below the national average -- in order to identify the factors causing these differences. To do so, we computed the degree of association between variables related to the students and to the schools with the scores obtained in the mathematical tests. The purpose of this analysis was to better understand the meaning of these scores and their causes and, above all, to propose educational policy actions for improving the students' mathematical performance. In this study, a 2-level regression model was applied to the data collected in the PISA 2015 tests. The first level included the factors related to the students and the second was composed of the variables related to the schools. Our results highlight the significant influence of factors such as immigrant status, grade repetition, location of the school (rural or urban) and economic and sociocultural status. The relevance of these factors to students' academic performance has been observed in previous editions of the PISA tests. We emphasise the need for action to improve students' mathematical performance and, therefore, their educational success.

Auditory hair cells form precise and sensitive staircase-like actin protrusions known as stereocilia. These specialized microvilli detect deflections induced by sound through the activation of mechano-electrical transduction (MET) channels located at their tips. At rest, a small MET channel current results in a constant calcium influx which regulates the morphology of the actin cytoskeleton in the shorter 'transducing' stereocilia. However, the molecular mechanisms involved in this novel type of activity-driven plasticity in the stereocilium cytoskeleton are currently unknown. Here, we tested the contribution of myosin XVA (MYO15A) isoforms, given their known roles in the regulation of stereocilia dimensions during hair bundle development and the maintenance of transducing stereocilia in mature hair cells. We used electron microscopy to evaluate morphological changes in the cytoskeleton of auditory hair cell stereocilia after the pharmacological blockage of resting MET currents in cochlear explants from mice that lacked one or all isoforms of MYO15A. Hair cells lacking functional MYO15A isoforms did not exhibit MET-dependent remodeling in their stereocilia cytoskeleton. In contrast, hair cells lacking only the long isoform of MYO15A exhibited increased MET-dependent stereocilia remodeling, including remodeling in stereocilia from the tallest 'non-transducing' row of the bundle. We conclude that MYO15A isoforms both enable and fine-tune the MET-dependent remodeling of the actin cytoskeleton in transducing stereocilia, while also contributing to the stability of the tallest row. [ABSTRACT FROM AUTHOR]

Neglected tropical diseases (NTDs), particularly those caused by trypanosomatid protozoa, impose a significant global burden, disproportionately affecting underserved communities in tropical and subtropical regions. Despite their high mortality rates, associated chronic conditions, and rapid spread due to globalization and climate change, NTDs have historically received minimal research investment. Additionally, existing treatments cause severe adverse effects. While animal models have contributed significantly to our understanding of these diseases, they are limited by technical and financial constraints. Current in vitro approaches predominantly focus on single-cell interactions on stiff substrates; thus, failing to capture tissue-level dynamics crucial for understanding host-parasite interactions. In this scoping literature review, we summarize emerging engineering applications to address these challenges by developing more complex in vitro models. We discuss 36 publications that describe novel strategies employing biomaterials, organoids, spheroids, and microfluidic devices to improve the mechanistic understanding of these NTDs. We also describe how these preclinical models are being used as screening platforms in the drug discovery and repurposing pipeline. To better understand the global scope of this research, we also performed a meta-analysis of the geolocation of the authors whose work was included in this review. This analysis uncovers uneven global participation in these efforts to combat NTDs. Ultimately, we draw attention to the need for a multidisciplinary and transnational approach to mitigate the impact of trypanosomatid NTDs and reduce health inequities globally. [ABSTRACT FROM AUTHOR]