The Glial Cell of Human Cutaneous Sensory Corpuscles: Origin, Characterization, and Putative Roles

Sensory corpuscles of human skin are structures located at the peripheral end of the mechanoreceptive neurons and function as low-threshold mechanoreceptors (LTMRs). In its structure, in addition to the axon, there are glial cells, not myelinating, that are organized in different ways according to the morphotype of sensitive corpuscle, forming the so-called laminar cells of Meissner’s corpuscles, the laminar cells of the inner core of Pacinian corpuscles, or cells of the inner core in Ruffini’s corpuscles. Classically the glial cells of sensory corpuscles have been considered support cells and passive in the process of mechanotransduction. However, the presence of ion channels and synapses-like systems between them and the axon suggests that corpuscular glial cells are actively involved in the transformation of mechanical into electrical impulses. This chapter is an update on the origin, development, cytoarchitecture, and protein profile of glial cells of sensitive corpuscles especially those of human glabrous skin

The Cutaneous Biopsy for the Diagnosis of Peripheral Neuropathies: Meissner’s Corpuscles and Merkel’s Cells

Cutaneous biopsy is a complementary method, alternative to peripheral nerve biopsy, for the analysis of nerve involvement in peripheral neuropathies, systemic diseases, and several pathologies of the central nervous system. Most of these neuropathological studies were focused on the intraepithelial nerve fibers (thin-myelinated Aδ fibers and unmyelinated C fibers), and few studies investigated the variations in dermal innervation, that is, large myelinated fibers, Merkel’s cell-neurite complexes, and Meissner’s corpuscles. Here, we updated and summarized the current data about the quantitative and qualitative changes that undergo MCs and MkCs in peripheral neuropathies. Moreover, we provide a comprehensive rationale to include MCs in the study of cutaneous biopsies when analyzing the peripheral neuropathies and aim to provide a protocol to study them

Immunohistochemical detection of PIEZO1 and PIEZO2 in human digital Meissner´s corpuscles

The cutaneous end organ complexes or cutaneous sensory corpuscles are specialized sensory organs associated to low-threshold mechanoreceptors. Mechano-gated proteins forming a part of ion channels have been detected in both the axon and terminal glial cells of Meissner corpuscles, a specific cutaneous end organ complex in the human glabrous skin. The main candidates to mechanotransduction in Meissner corpuscles are members of the Piezo family of cationic ion channels. PIEZO2 has been detected in the axon of these sensory structures whereas no data exists about the occurrence and cell localization of PIEZO1. Skin samples (n = 18) from the palmar aspect of the distal phalanx of the first and second fingers were analysed (8 female and 10 males; age range 26 to 61 26–61 years). Double immunofluorescence for PIEZO1 and PIEZO2 together with axonal or terminal glial cell markers was captured by laser confocal microscopy, and the percentage of PIEZOs positive Meissner corpuscles was evaluated. MCs from human fingers showed variable morphology and degree of lobulation. Regarding the basic immunohistochemical profile, in all cases the axons were immunoreactive for neurofilament proteins, neuron specific enolase and synaptophysin, while the lamellar cells displayed strong S100P immunoreactivity. PIEZO1 was detected co-localizing with axonal markers, but never with terminal glial cell markers, in the 56% of Meissner corpuscles; weak but specific immunofluorescence was additionally detected in the epidermis, especially in basal keratinocytes. Similarly, PIEZO2 immunoreactivity was found restricted to the axon in the 85% of Meissner corpuscles. PIEZO2 positive Merkel cells were also regularly found. PIEZO1 and PIEZO2 are expressed exclusively in the axon of a subpopulation of human digital Meissner corpuscles, thus suggesting that not only PIEZO2, but also PIEZO1 may be involved in the mechanotransduction from low-threshold mechanoreceptor

Mechanomyographic measures of muscle contractile properties are influenced by electrode size and stimulation pulse duration

The aim was to determine the effects of changing pulse duration and electrode size on muscle contractile properties. Thirty-six healthy young male participated in the study (age 24.8 ± 5.8 years; height 178.2 ± 0.6 cm; body mass 71.8 ± 7.3 kg; self-reported weekly moderate intensity activity 3.5 ± 1.2 h·week−1). Tensiomyography was used to assess rectus femoris (RF) and vastus medialis (VM) muscles neuromuscular properties of the dominant leg according to the electrode size (3.2–5 cm) and the stimulus length (0.2, 0.5, and 1 ms). Maximal radial displacement (Dm); Contraction time (Tc); Delay time (Td); Sustained time (Ts) and Half relaxation time (Tr) were measured. Relative and absolute reliability was quantified. To analyze the effects of the electrode and the stimulus length, a repeated-measures analysis of variance was used. Dm and Tc parameters showed for both muscles an excellent relative (0.95–0.99) and absolute reliability (1.6–4.2%). However, Ts and Tr showed low values of absolute reliability (4.4–40.9%). The duration of the stimulus length applied to the RF and VM and electrode size significantly influences muscle’s contractile properties (p < 0.05; η2p = 0.09–0.60). The Dm increases substantially as the duration of the stimulus increases and with the use of the larger electrode in both muscles. However, Tc and Td are less affected by both conditions and not entirely clear. Practically, our study suggests that a stimulus pulse duration of 1 ms together with a 5 × 5 cm electrode is necessary to reach a reliable and reproducible assessment of both RF and VM muscles contractile properti

Mechanomyographic Measures of Muscle Contractile Properties are Infuenced by Electrode Size and Stimulation Pulse Duration

The aim was to determine the efects of changing pulse duration and electrode size on muscle contractile properties. Thirty-six healthy young male participated in the study (age 24.8±5.8 years; height 178.2±0.6cm; body mass 71.8±7.3kg; self-reported weekly moderate intensity activity 3.5±1.2h·week−1). Tensiomyography was used to assess rectus femoris (RF) and vastus medialis (VM) muscles neuromuscular properties of the dominant leg according to the electrode size (3.2–5cm) and the stimulus length (0.2, 0.5, and 1ms). Maximal radial displacement (Dm); Contraction time (Tc); Delay time (Td); Sustained time (Ts) and Half relaxation time (Tr) were measured. Relative and absolute reliability was quantifed. To analyze the efects of the electrode and the stimulus length, a repeated-measures analysis of variance was used. Dm and Tc parameters showed for both muscles an excellent relative (0.95–0.99) and absolute reliability (1.6–4.2%). However, Ts and Tr showed low values of absolute reliability (4.4–40.9%). The duration of the stimulus length applied to the RF and VM and electrode size signifcantly infuences muscle’s contractile properties (p<0.05; η2 p=0.09–0.60). The Dm increases substantially as the duration of the stimulus increases and with the use of the larger electrode in both muscles. However, Tc and Td are less afected by both conditions and not entirely clear. Practically, our study suggests that a stimulus pulse duration of 1ms together with a 5 × 5cm electrode is necessary to reach a reliable and reproducible assessment of both RF and VM muscles contractile properties.Ciencias de la Actividad Física y del Deport

Titin Missense Variants as a Cause of Familial Dilated Cardiomyopathy.

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UPMSat-2 Micro-Satellite: In-orbit Technological Demonstration for Education and Science

The UPMSat-2 micro-satellite was launched on September the 3rd 2020 at 01:51:10 UTC from Kourou spaceport in French Guyana. The VV16 Vega Flight has been the first low Earth orbit rideshare commercial flight with a total of 53 satellites (7 of them micro-satellites) to be released by the launch vehicle, arranged in the modular SSMS (Small Spacecraft Mission Service) dispenser. UPMSat-2 is an educational, scientific and in-orbit technological demonstration microsatellite project led by the IDR/UPM research institute from Universidad Politécnica de Madrid (UPM), Spain. This mission can be considered as a logical extension of the IDR/UPM Institute activities focused on designing small satellites to be used as educational platforms of first level. Thereby, UPMSat-2 (as well as its precursor, the UPMSat-1) has the main objective to give students the competences for designing, analyzing, manufacturing, integrating, testing and operating the platform. UPMSat-2 also includes a set of scientific payloads and equipment to be tested in space, provided by research institutions and private companies. The UPMSat-2 is a 50 kg-class microsatellite developed for a 2-year LEO mission with a geometrical envelope of 0.5 x 0.5 x 0.6 m. Since launch, the satellite is orbiting the Earth in a sun-synchronous orbit of 500 km of altitude, passing over the IDR/UPM ground station four times a day. The satellite operation is being carried out by students and professors of the Master in Space Systems (MUSE), an official Master’s program of UPM organized by IDR/UPM. This work describes the most relevant characteristics of UPMSat-2, its payloads, technological contributions, and the main activities performed up to the launch, including participation in the launch campaign in French Guyana. The lessons learned during the mission are also summarized. Finally, the importance and benefits of incorporating actual space systems design and development within academic programs is also emphasized, as it improves these programs with constant and direct feedback

Healthcare workers hospitalized due to COVID-19 have no higher risk of death than general population. Data from the Spanish SEMI-COVID-19 Registry

Aim To determine whether healthcare workers (HCW) hospitalized in Spain due to COVID-19 have a worse prognosis than non-healthcare workers (NHCW). Methods Observational cohort study based on the SEMI-COVID-19 Registry, a nationwide registry that collects sociodemographic, clinical, laboratory, and treatment data on patients hospitalised with COVID-19 in Spain. Patients aged 20-65 years were selected. A multivariate logistic regression model was performed to identify factors associated with mortality. Results As of 22 May 2020, 4393 patients were included, of whom 419 (9.5%) were HCW. Median (interquartile range) age of HCW was 52 (15) years and 62.4% were women. Prevalence of comorbidities and severe radiological findings upon admission were less frequent in HCW. There were no difference in need of respiratory support and admission to intensive care unit, but occurrence of sepsis and in-hospital mortality was lower in HCW (1.7% vs. 3.9%; p = 0.024 and 0.7% vs. 4.8%; p<0.001 respectively). Age, male sex and comorbidity, were independently associated with higher in-hospital mortality and healthcare working with lower mortality (OR 0.211, 95%CI 0.067-0.667, p = 0.008). 30-days survival was higher in HCW (0.968 vs. 0.851 p<0.001). Conclusions Hospitalized COVID-19 HCW had fewer comorbidities and a better prognosis than NHCW. Our results suggest that professional exposure to COVID-19 in HCW does not carry more clinical severity nor mortality