RESUMEN
The mouse small intestine shows profound variability in gene expression along the crypt-villus axis1,2. Whether similar spatial heterogeneity exists in the adult human gut remains unclear. Here we use spatial transcriptomics, spatial proteomics and single-molecule fluorescence in situ hybridization to reconstruct a comprehensive spatial expression atlas of the adult human proximal small intestine. We describe zonated expression and cell type representation for epithelial, mesenchymal and immune cell types. We find that migrating enterocytes switch from lipid droplet assembly and iron uptake at the villus bottom to chylomicron biosynthesis and iron release at the tip. Villus tip cells are pro-immunogenic, recruiting γδ T cells and macrophages to the tip, in contrast to their immunosuppressive roles in mouse. We also show that the human small intestine contains abundant serrated and branched villi that are enriched at the tops of circular folds. Our study presents a detailed resource for understanding the biology of the adult human small intestine.
RESUMEN
BACKGROUND: To evaluate chorda tympani nerve function as measured by unilateral increases of gustatory thresholds in the presence of ipsilateral acute otitis media. METHODS: Prospective clinical study comparing electrogustometric measurements was conducted to evaluate the taste thresholds of each side of the tongue in a patient during an acute episode of unilateral acute otitis media. Included were patients aged 12-40 who presented to the emergency department and outpatient ear, nose, and throat clinic of a university-affiliate tertiary medical center with unilateral acute otitis media between January 2019 and January 2020 and consented to the study. RESULTS: Eleven patients were initially recruited into the study, and 10 patients aged (mean ± standard deviation) 26.1 ± 11.2 years comprised the final study group. Taste thresholds were significantly elevated on the side ipsilateral to the ear affected by acute otitis media (P < .05). CONCLUSION: Chorda tympani nerve conductance is impaired during the acute stage of acute otitis media. This may have implications in the understanding of peripheral neural properties during acute middle ear inflammatory conditions and on the diagnosis of acute otitis media.
Asunto(s)
Otitis Media , Umbral Gustativo , Humanos , Umbral Gustativo/fisiología , Proyectos Piloto , Estudios Prospectivos , Otitis Media/complicaciones , Nervio de la Cuerda del TímpanoRESUMEN
Exploring the properties of action potentials is a crucial step toward a better understanding of the computational properties of single neurons and neural networks. The voltage-gated sodium channel is a key player in action potential generation. A comprehensive grasp of the gating mechanism of this channel can shed light on the biophysics of action potential generation. However, most models of voltage-gated sodium channels assume a concerted Hodgkin and Huxley kinetic gating scheme. However, it is not clear if Hodgkin and Huxley models are suitable for use in action potential simulations of central nervous system neurons. To resolve this, we investigated the activation kinetics of voltage-gated sodium channels. Here we performed high resolution voltage-clamp experiments from nucleated patches extracted from the soma of layer 5 (L5) cortical pyramidal neurons in rat brain slices. We show that the gating mechanism does not follow traditional Hodgkin and Huxley kinetics and that much of the channel voltage-dependence is probably due to rapid closed-closed transitions that lead to substantial onset latency reminiscent of the Cole-Moore effect observed in voltage-gated potassium conductances. Thus, the classical Hodgkin and Huxley description of sodium channel kinetics may be unsuitable for modeling the physiological role of this channel. Furthermore, our results reconcile between apparently contradicting studies sodium channel activation. Our findings may have key implications for the role of sodium channels in synaptic integration and action potential generation.
RESUMEN
New types of robots inspired by biological principles of assembly, locomotion, and behavior have been recently described. In this work we explored the concept of robots that are based on more fundamental physical phenomena, such as fluid dynamics, and their potential capabilities. We report a robot made entirely of non-Newtonian fluid, driven by shear strains created by spatial patterns of audio waves. We demonstrate various robotic primitives such as locomotion and transport of metallic loads-up to 6-fold heavier than the robot itself-between points on a surface, splitting and merging, shapeshifting, percolation through gratings, and counting to 3. We also utilized interactions between multiple robots carrying chemical loads to drive a bulk chemical synthesis reaction. Free of constraints such as skin or obligatory structural integrity, fluid robots represent a radically different design that could adapt more easily to unfamiliar, hostile, or chaotic environments and carry out tasks that neither living organisms nor conventional machines are capable of.