Neuron-like function of the nephron central command

SUMMARYInteroceptive neurons that sense and regulate our internal milieu have been identified in several organs except in the kidney cortex despite its major importance in maintaining body homeostasis. Here we report that the chief kidney cell type of the macula densa (MD) forms coordinated neural networks in each nephron that resemble peripheral ganglia. A combined in vivo single-cell 4D physiology (sc4DP) and scRNA sequencing approach identified the MD mechanisms of neuronal differentiation, heterogeneity (pacemaker MD cells), sensing of the local and systemic environment via multi-organ crosstalk, and regulation of organ functions by acting as the nephron central command. Consistent with their neuron-like nature, MD cells express the molecular fingerprint of neurodegeneration. Here we put forth the single-cell MD model and concept of local neural networks that control organ and body functions via interoception in normal physiological state and use an integrated mechanism of neurodegeneration in disease.

Endurance exercise: a model of physiological integration

Endurance exercise is a model of physiological integration. There is no other animal activity in which cardiovascular, respiratory, metabolic-endocrine and neuromuscular functions are activated at the same time. Even apparently, silent functions are essential during exercise (digestive, renal). During long-term exercise, the absorption of water and carbohydrates is a determining factor in performance. Kidney function plays a fundamental role in trying to preserve the hydro-electrolyte balance during exercise. In this work we present an integrative physiological perspective during dynamic exercise (mobilization of a large muscle mass with a low to moderate degree of strength development), both from the point of view of health and performance. The response of the heart rate in the first moments of exercise is a good example of the feedforward mechanism. Overall, the nervous system has two control mechanisms: feedforward and feedback. These depend on the central command, a more functional than anatomical entity. The feedforward system allows to immediately start the cardiovascular and respiratory systems. This mechanism is important because it activates the organism to overcome resting state. The feedback system is equally important because it allows the central command to receive the necessary information to “order” the appropriate response according to the intensity of the exercise. The information for retrocontrol comes from various receptors located in: the muscles, the respiratory system and the cardiovascular system. It is complex information that the central nervous system processes with exquisite precision, as can be seen in in endurance exercise.

Emergency Department Changes to Combat COVID-19 in Oman

Our hospital is one of the tertiary care hospitals in Oman receiving COVID-19 (C19) patients. To meet the expected surge of patients, a number of changes to the ED (Emergency Department), especially regarding capacity building and patient flow. At first, few changes were made to the main ED, which mainly includes addition of COVID suspect room (CSR) with use of separate resuscitation area. The major drawback of above-mentioned system was the inability to see more than two patients simultaneously. Later separate COVID ED (CED) was utilized. In CED pending admissions was the major problem, as C19 ward (COVID ward) and C19 ICU (COVID ICU) were becoming full, this problem was solved through central command help. In the normal ED the main problem was the presentation of C19 positive patients, sometimes hiding their symptoms and reaching inside main ED exposing the staff and patients. In order to combat this problem, all patients with acute respiratory problem, even if C19 is not suspected, were taken to the corner cubicle. In this report, the changes made to ED to combat C19 situation is discussed.

Authoritarian clientelism: the case of the president’s ‘creatures’ in Cameroon

Within this article, we aim at exploring the topic of clientelism in Cameroon as a species of a wider phenomenon affecting Central and Western Francophone Africa. Our argument is that, in spite of the repeated efforts of reinforcing the local power structures, we have witnessed a process of centralisation of clientelism: the new networks are shaped around the ‘Creatures’, who are the President Paul Biya’s formal or informal appointees and play the role of nodal elements relying the rest of the chain to the central command. This happened on the expenses of the locally dispersed and more autonomous clientelistic groups that were either included in or smashed by the pyramidal Creatures’ structured. In order to test our assumption, we analysed a specific body of literature on the theorization of clientelism and on its African and Cameroonian specificity and organized four focus groups with the actual and former members of the clientelistic chains at different levels (central, regional and local). If our main presupposition proved to be generally correct, one of the sub-arguments was only partially validated through this empirical component of our research.

Activation of Mechanoreflex, but not Central Command, Delays Heart Rate Recovery after Exercise in Healthy Men

This study tested the hypotheses that activation of central command and muscle mechanoreflex during post-exercise recovery delays fast-phase heart rate recovery with little influence on the slow phase. Twenty-five healthy men underwent three submaximal cycling bouts, each followed by a different 5-min recovery protocol: active (cycling generated by the own subject), passive (cycling generated by external force) and inactive (no-cycling). Heart rate recovery was assessed by the heart rate decay from peak exercise to 30 s and 60 s of recovery (HRR30s, HRR60s fast phase) and from 60 s-to-300 s of recovery (HRR60−300s slow phase). The effect of central command was examined by comparing active and passive recoveries (with and without central command activation) and the effect of mechanoreflex was assessed by comparing passive and inactive recoveries (with and without mechanoreflex activation). Heart rate recovery was similar between active and passive recoveries, regardless of the phase. Heart rate recovery was slower in the passive than inactive recovery in the fast phase (HRR60s=20±8vs.27 ±10 bpm, p<0.01), but not in the slow phase (HRR60−300s=13±8vs.10±8 bpm, p=0.11). In conclusion, activation of mechanoreflex, but not central command, during recovery delays fast-phase heart rate recovery. These results elucidate important neural mechanisms behind heart rate recovery regulation.