With the inrush of new data the recent clear division of neural, hormonal and immunological regulation has been seriously complicated. Both central and peripheral neural tissue produce over 30 neuropeptides, among which are many classic peptide hormones. A steroid biosynthetic pathway has been demonstrated in oligodendrocytes. However, the distribution and role of peptydoergic neurons within the reproductive system are only superficially known among farm animals. Neurons have receptors for many hormones and interleukins. Cells of the immune system, in addition to secretion of many interleukins and interferons, produce neuropeptides locally and they possess specific receptors for them as well. Till now, the interaction between the nervous, hormonal and immunological systems has not been taken into account while investigating the functions of ovarian follicles, the corpus luteum, oviduct and uterus. The penetration of blood and lymphatic vessels by hormones, neuropeptides and cytokins has not been taken into consideration also. The counter current transfer of many steroid and peptide hormones from ovarian venous and lymphatic effluent to arterial blood supplying the ovary and through arterial anastomoses of the oviduct and uterus has been hithero shown. It has been demonstrated that thanks to this system, arterial blood supplying the uterus and oviduct has, in physiological conditions, a much higher level of some steroid hormones such as progesterone and androstendione, 37% and 36% respectively, than in systemic blood. Recently, a powerful exchange system for resupplying hormones to the brain which is dependent on the phase of the estrous cycle, has been discovered. It has also been demonstrated that neuropeptides LH-RH, beta-endorphin and oxytocin as well as the steroid hormone progesterone, were counter current transferred from venous to arterial blood at the perihypophyseal cavernous sinus and carotid rete in sheep and gilts, but only during specific periods of reproductive activity. The mechanism of this process is still unknown. The role of peptydoergic neurons and cytokins in vascular permeability during hormone counter current transfer in the broad ligament vasculature, perihypophyseal cavernous sinus and carotid rete has not been investigated. It is suggested that progress in this area may change our point of view on many basic regulatory mechanisms involved in animal reproductive physiology.
Diabetes, a multifaceted metabolic disorder characterized by inadequate insulin production or resistance, intricately intertwines with the challenging landscape of wound healing, particularly in the context of diabetic wounds. This review embarks on a comprehensive exploration, commencing with an overview of diabetes physiology, setting the stage for understanding its intricate interplay with wound healing complexities. Navigating through the physiology of diabetic wounds, this review encapsulates their classification and the intricate molecular and cellular mechanisms orchestrating the healing process. However, amidst commendable advancements, a discernible research gap remains, urging a more nuanced comprehension of diabetic wound pathophysiology. Examining treatment approaches, this article critically assesses various methods for diabetic wound healing efficacy, rooted in recent studies. It explores advanced therapies and emerging technologies, envisioning possibilities such as 3D printing and smart dressing applications. Nonetheless, integrating these technologies into clinical practice awaits exploration, highlighting a research gap in standardizing these advancements. Infection control and antibiotics are pivotal in diabetic wound management. This review underscores their importance, stressing the need for refined research strategies to optimize antibiotic use and combat evolving bacterial resistance. Furthermore, advocating for patient-centered care and education, this review emphasizes holistic approaches, underscoring a persistent gap in seamlessly integrating patient education into routine wound management protocols. This review offers comprehensive insights into diabetic wound physiology, treatment modalities, and emerging technologies while highlighting persistent research gaps demanding further exploration and refinement.
Objective: To identify author collaborations and impact; participating countries, institutions, and journals; evaluate the knowledge base; and analyze research hotspots and frontiers in teaching reforms in physiology. Methods: Articles and reviews related to teaching reforms in physiology published between January 1, 2012, and December 31, 2021, were obtained from the Web of Science Core Collection. Two Scientometric software applications (CiteSpace 5.7 and VOSviewer 1.6.15) were used to perform bibliometric and knowledge-map analysis, generate network maps, and identify research trends and top keywords, authors, co-cited authors, institutions, countries, journals, and references. Results: published the most papers on physiology teaching reforms and was also the top co-cited journal in the Medicine/Medical/Clinical, Psychology/Education/Health, and Neurology/Sports/Ophthalmology fields. The United States and University of California published the most physiology teaching publications in the search criteria. Ten references (research articles and reviews) on mechanisms and diseases were identified as the knowledge base. The mainstream research directions were education, Alzheimer's disease, performance, physiology, and risk factors. Mental health and emotion regulation are increasing in significance and may become new hotspots. The research trend to move from the field of pain pathogenesis to the field of neuropsychiatry has become increasingly clear. This tendency away from peripheral system-based disorders to central system-based orders is inextricably linked to further developments in physiological understanding of the brain. Conclusion: This study analyzed the research hot spots and frontiers of teaching reforms on in physiology using bibliometric and visual methods. Based on the results, rehabilitation, neurosciences, and infectious disease are hot topics in physiology. In particular, the pathogenesis of neurological diseases, treatment strategies, and technology updates have gradually become research hotspots. We predict that this trend is closely related to the implementation of brain research programs in various countries. These findings provide helpful references for scholars focusing on physiology education.
Exercise in space has evolved from rudimental testing into the multi-modal countermeasure (CM) programme used on the International Space Station (ISS). However, with the constraints of future exploration missions, replicating this programme will be a significant challenge. Recent ISS data suggest that crew now experience only relatively moderate levels of microgravity (G)-induced adaptation, although significant variation remains, with some crew displaying marked changes despite significant time/effort investment. This suggests that the efficacy of exercise CMs is yet to be optimised for all individuals. With the current suite of exercise devices operational for almost a decade, and with exploration approaching, it is timely to re-visit the terrestrial literature to identify new knowledge relevant to the management of µG adaptation. As such, the aim of the Frontiers Research Topic Optimisation of Exercise Countermeasures for Human Space Flight – Lessons from Terrestrial Physiology and Operational Considerations, is to synthesize current terrestrial exercise physiology knowledge and consider how this might be employed to optimise the use of exercise CM. The purpose of this Perspective, which serves as a preface to the Research Topic is three-fold: to briefly review the use and apparent efficacy of exercise in space, to consider the impact of the transition from ISS to exploration mission vehicles and habitats and to identify areas of terrestrial exercise physiology where current knowledge might contribute to the optimisation of CM exercise for exploration. These areas include individual variation, high intensity interval training, strength development/maintenance, concurrent training, plyometric/impact exercise and strategies to enhance exercise efficacy.
POINT-COUNTERPOINTPoint:Counterpoint: Respiratory sinus arrhythmia is due to a central mechanism vs. respiratory sinus arrhythmia is due to the baroreflex mechanismDwain L. EckbergDwain L. EckbergPublished Online:01 May 2009https://doi.org/10.1152/japplphysiol.91107.2008This is the final version - click for previous versionMoreSectionsPDF (139 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations POINT: RESPIRATORY SINUS ARRHYTHMIA IS DUE TO A CENTRAL MECHANISMBlood pressure and heart periods fluctuate at respiratory frequencies in healthy humans. Some researchers (8, 23) explain this as a cause-and-effect relation: blood pressure changes trigger baroreflex-mediated R-R interval changes. Here I make the case that respiratory sinus arrhythmia is a central phenomenon that is independent of blood pressure changes. I base this argument on several well-documented physiological facts.Vagal-cardiac motoneuron membrane potentials fluctuate at respiratory frequencies (16), modulate responsiveness of vagal motoneurons to arterial baroreceptor inputs (12, 13), and impose a respiratory rhythm on vagal-cardiac nerve traffic and heart periods (18). Central respiratory gating of vagal motoneuron responsiveness (11) is sufficient to explain respiratory sinus arrhythmia.The cascade of events comprising a vagal baroreflex response does not play out instantaneously; each step in the sequence takes time. Therefore, a critical question is, how much time is required between the beginning of the cascade sequence, a change of arterial pressure, and the end of the sequence, a change of heart period?Latencies of individual components of vagal baroreflex responses have been measured directly in animals and include transduction of baroreceptive artery stretch into baroreceptor firing, 18 ms (19); polysynaptic central transactions, 26 ms (21); transmission of vagus nerve traffic from the brain stem to the sinoatrial node, 2 ms (6); and sinoatrial node responses, 120 ms (6). Simple addition of these latencies (14) yields a vagal baroreflex arc latency of 166 ms; the great majority of this latency, 72%, reflects the kinetics of sinoatrial node responses to released acetylcholine.These animal data comport well with results obtained with electrical carotid sinus nerve stimulation and abrupt intense neck suction in humans. Minimal human vagal baroreflex latency is remarkably short—less than 0.5 s (5, 25), and possibly as short as 0.24 s (9). However, the operative word in the preceding sentence is “minimal”; data derived from highly unphysiological experimental interventions do not necessarily answer the question, what is vagal-cardiac baroreflex latency in the arterial pressure, heart period transactions that occur in everyday life? The short answer to this question is this: vagal baroreflex responses do not occur instantaneously—they take time. The question then becomes, how much time?In one of the earliest quantitative studies of human vagal baroreflexes, Smyth, Sleight, and Pickering (27) gave intravenous bolus injections of angiotensin, and plotted heart period responses as functions of preceding arterial pressure increases. They reported that the best linear fits were obtained when each systolic pressure during the pressure rise was correlated with the R-R interval of the heart beat that followed the pressure pulse. In 1986 (15), we confirmed this observation and showed that most spontaneously occurring baroreflex sequences (3) yield the highest correlation coefficients when each arterial pulse is related to the following R-R interval.When baroreceptors are stimulated with abrupt intense neck suction, the time from the onset of the stimulus until the maximum P-P interval prolongation averages 1.5 s (2). (In a subject with a P-R interval of 0.15 s, the stimulus to R wave latency becomes 1.65 s.) Wallin and Nerhed (29) signal averaged arterial pressures and R-R intervals on the peaks of muscle sympathetic bursts and reported that diastolic pressure rises after sympathetic bursts and R-R intervals peak between 1.8 and 4.8 s (average, 2.9) later.The next question is, what is the latency between respiratory frequency arterial pressure and R-R interval changes? We performed cross-spectral analysis of systolic pressures and R-R intervals in two studies (7, 20), the results of which are summarized in Fig. 1.Fig. 1.Cross-spectral analysis of systolic pressures and R-R intervals in two studies (7, 20). Data shown in A and B were recorded during fixed-frequency breathing at progressive angles of passive upright tilt (7). The average phase angle was −53° at the low frequency (A) and did not change significantly during tilt (P = 0.48, linear regression). Data shown in C and D were recorded during fixed-frequency breathing (left) and conventional mechanical ventilation, both at a frequency of 0.25 Hz (20). Respiratory frequency phase angles averaged −25° during fixed-frequency breathing (D; left) and 49° during mechanical ventilation (D; right). Neither study reported fixed phase angles and respiratory frequencies (B and D).Download figureDownload PowerPointData in Fig. 1, A and B, were recorded during fixed-frequency breathing at progressive angles of passive upright tilt (7). The average phase angle was minus 53° at the low frequency (A) and did not change significantly during tilt (P = 0.48, linear regression). Such analyses do not indicate whether systolic pressure changes precede R-R interval changes [by 1.6 s (53°/360°·11.1 s)] or follow R-R interval changes [by 9.5 (11.1 − 1.6) s]. A latency of 9.5 s is not consistent with baroreflex mechanisms; systolic pressure returns to usual levels within 3 s after transient reductions of arterial pressure (30). Therefore, it is likely that low frequency R-R interval changes follow systolic pressure changes, with an average latency that is consistent with arterial baroreflex physiology (2).Figure 1B shows an entirely different picture for respiratory-frequency systolic pressure—R-R interval phase angles. The phase was positive in the supine position (extreme left) and declined systematically (P = 0.001) to negative levels, in proportion to the tilt angle. Average calculated latencies between systolic pressure and P-P intervals (subtracting an assumed P-R interval of 0.15 s) from these data were plus 0.3 s in the supine position and minus 0.1 s at the 80° the tilt position. Other studies (8, 23) document similar latencies for both low- and respiratory-frequency systolic pressure-R-R interval cross-spectra in supine subjects.Data shown in Fig. 1, C and D, (20) were recorded from supine subjects during controlled-frequency breathing and conventional mechanical ventilation (both at 0.25 Hz). Calculated latencies averaged −2.7 and −3.0 s at low frequencies (P = 0.88, Mann-Whitney Rank Sum, Fig. 1C) and −0.28 and 0.53 s at respiratory frequencies (P = 0.001, Fig. 1D) during spontaneous breathing and mechanical ventilation. One point that stands out in this figure [and in other studies (4, 7, 10, 24)] is that systolic pressure-R-R interval phase angles at respiratory frequencies vary greatly.Therefore, if respiratory frequency R-R interval fluctuations are baroreflex-mediated, baroreflex latencies—mainly reflecting the kinetics of acetylcholine effects on the sinoatrial node—vary systematically, according to the physiological circumstances of the moment. Saul and coworkers (24) proposed a vastly simpler explanation: R-R interval changes follow breathing, not pressure, with a nearly fixed time delay of ∼0.3 s.Although I emphasize baroreflex latencies, other types of evidence point to a respiratory, non-baroreflex causation of respiratory R-R interval changes. In anesthetized dogs, R-R interval fluctuations follow phrenic nerve activity and persist when intrathoracic pressure fluctuations are abolished (26). Thoracotomy increases respiratory blood pressure changes but decreases R-R interval fluctuations (17). Fixed-rate atrial pacing reduces respiratory frequency blood pressure fluctuations (28); if baroreflex responses buffer blood pressure fluctuations, blood pressure oscillations should be greater, not less, during fixed-rate pacing. Conventional mechanical ventilation, which presumably silences phrenic motoneurons, augments respiratory blood pressure fluctuations, but nearly abolishes respiratory R-R interval fluctuations (20). Removal of respiratory influences on systolic pressures and R-R intervals by partialization reduces coherence between the latter signals from close to 1.0 to <0.5 (1).I subscribe to the view that blood pressure changes provoke parallel R-R interval changes—a cause-and-effect baroreflex relation. However, in this physiology, timing is everything. Before I accept the view that R-R interval fluctuations at respiratory frequencies are baroreflex responses, someone must explain 1) how an arterial pressure change can, within 0.1 s, speed or slow the appearance of the next P wave; 2) how the kinetics of sinoatrial nodal responses to acetylcholine are modulated systematically by body position and breathing frequency; and most difficult of all, 3) how baroreflex R-R interval responses can occur before the arterial pressure changes that provoke them. 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J Am Col Cardiol 13: 69–75, 1989.Crossref | PubMed | ISI | Google Scholar Download PDF Previous Back to Top Next FiguresReferencesRelatedInformation Cited ByRespiratory patterns and baroreflex function in heart failure8 February 2023 | Scientific Reports, Vol. 13, No. 1Comparative features of the morphometric correlates of blood pressure response to physical load of qualified athletes in some sports1 April 2023 | Physical Rehabilitation and Recreational Health Technologies, Vol. 8, No. 1Analysis of Respiratory Sinus Arrhythmia and Directed Information Flow between Brain and Body Indicate Different Management Strategies of fMRI-Related Anxiety27 March 2023 | Biomedicines, Vol. 11, No. 4Autonomic Cardiovascular Control in Health and Disease30 March 2023Cerebral blood flow response to cardiorespiratory oscillations in healthy humansAutonomic Neuroscience, Vol. 245Autonomic nervous system assessment using heart rate variability21 February 2023 | Acta Cardiologica, Vol. 5Breathing exercise for hypertensive patients: A scoping review25 January 2023 | Frontiers in Physiology, Vol. 14On the significance of estimating cardiorespiratory coupling strength in sports medicine4 January 2023 | Frontiers in Network Physiology, Vol. 2Cardiorespiratory coupling strength in athletes and non-athletesRespiratory Physiology & Neurobiology, Vol. 305Respiratory Sinus Arrhythmia is Mainly Driven by Central Feedforward Mechanisms in Healthy Humans7 July 2022 | Frontiers in Physiology, Vol. 13Embracing a curiosity‐driven approach in the microneurographic exploration of the human vagus nerves9 June 2022 | The Journal of Physiology, Vol. 600, No. 13Negative respiratory sinus arrhythmia (nRSA) in the MRI-scanner - a physiologic phenomenon observed during elevated anxiety in healthy personsPhysiology & Behavior, Vol. 245Variability of cardiorespiratory interactions under different breathing patternsBiomedical Signal Processing and Control, Vol. 71Information decomposition in the frequency domain: a new framework to study cardiovascular and cardiorespiratory oscillations25 October 2021 | Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 379, No. 2212Cardiopulmonary coupling indices to assess weaning readiness from mechanical ventilation6 August 2021 | Scientific Reports, Vol. 11, No. 1MRI-related anxiety can induce slow BOLD oscillations coupled with cardiac oscillationsClinical Neurophysiology, Vol. 132, No. 9Scaling of heart rate with breathing frequency and body mass in cetaceans14 June 2021 | Philosophical Transactions of the Royal Society B: Biological Sciences, Vol. 376, No. 1830Influence of respiration frequency on heart rate variability parameters: A randomized cross-sectional studyJournal of Back and Musculoskeletal Rehabilitation, Vol. 157The role of the autonomic nervous system in the patterns of heart rate fragmentationBiomedical Signal Processing and Control, Vol. 67Longitudinal Assessment of Autonomic Function during the Acute Phase of Spinal Cord Injury: Use of Low-Frequency Blood Pressure Variability as a Quantitative Measure of Autonomic FunctionJournal of Neurotrauma, Vol. 38, No. 3Second Ventilatory Threshold Assessed by Heart Rate Variability in a Multiple Shuttle Run Test7 August 2020 | International Journal of Sports Medicine, Vol. 42, No. 01Traube–Hering waves are formed by interaction of respiratory sinus arrhythmia and pulse pressure modulation in healthy menWilliam H. Barnett, Elizaveta M. Latash, Robert A. Capps, Thomas E. Dick, Erica A. Wehrwein,* and Yaroslav I. Molkov*18 November 2020 | Journal of Applied Physiology, Vol. 129, No. 5Autonomic Nervous System and Recall Modeling in Audiovisual Emotion-Mediated Advertising Using Partial Least Squares-Path Modeling30 October 2020 | Frontiers in Psychology, Vol. 11How to Use Heart Rate Variability: Quantification of Vagal Activity in Toddlers and Adults in Long-Term ECG21 October 2020 | Sensors, Vol. 20, No. 20The use of biofeedback in the treatment of ADHD in childrenDiskuze v psychologii, Vol. 2, No. 1Can Slow Deep Breathing Reduce Pain? An Experimental Study Exploring MechanismsThe Journal of Pain, Vol. 21, No. 9-10Partial Information Decomposition in the to Control Mechanisms of Heart Rate Variability at and at is to Heart Rate baroreflex sequence method at does not interactions but the heart rate to blood pressure variability April 2020 | Vol. No. for of Heart and Autonomic in A Transactions on Vol. No. analysis of fluctuations in heart rate and breathing when the autonomic in with of Vol. No. in Physiology, Vol. to A of | Frontiers in Physiology, Vol. of heart rate February | Scientific Reports, Vol. No. of heart rate variability biofeedback is by May | Scientific Reports, Vol. No. of inspiratory load on cardiovascular responses to breathing at 0.1 July | Vol. No. baroreflex is one of the of the heart period variability de and | Journal of and Physiology, Vol. No. with breathing heart rate and slow June | Journal of Vol. 13, No. for in with Vol. within the in from July | Vol. 21, No. of the of Cardiovascular Control during in Recreational Rate to in the Human and March | The Journal of Neuroscience, Vol. No. quantitative of between blood pressure fluctuations and the respiratory sinus | & Biological Engineering & Vol. No. Information Decomposition Control Mechanisms of Heart Rate Variability at and May | Vol. 21, No. Temporal and the by or February | Frontiers in Physiology, Vol. of Respiratory Sinus Arrhythmia | Breathing the of Control in Healthy and Heart | Vol. 20, No. of in A in October | Frontiers in Physiology, Vol. for Heart Rate Variability in Simple in Average Heart October | Frontiers in Physiology, Vol. index of cardiac autonomic on respiration derived from M. and August | Journal of and Physiology, Vol. No. patterns of from different cardiac and using short-term | Physiology and Vol. 38, No. interactions in and for L. J. and July | Journal of and Physiology, Vol. No. to June | Frontiers in Physiology, Vol. in the in and Vol. autonomic November | Journal of Vol. No. physiology approach to the assessment of the between sinoatrial and ventricular cardiac June | Vol. 38, No. in physiological April | Vol. 38, No. to Cardiovascular August A to Cardiovascular and August Sinus Arrhythmia and with to Minimal by with Transfer for the Study of Cardiovascular and Transactions on Vol. of cardiac vagal and respiratory sinus | The Journal of Physiology, Vol. No. of Heart and in October | Frontiers in Physiology, Vol. modulation of human autonomic function on July | The Journal of Physiology, Vol. No. of heart rate is for the of the and indices of heart A in and Medicine, Vol. for on and Heart rate variability to May | Vol. No. of the human and April | Journal of and Physiology, Vol. No. of autonomic on the oscillations of ventricular action in A. and | Journal of and Physiology, Vol. No. and in cardiovascular and cardiorespiratory for the study of and Transfer in Heart Variability during July | Vol. 10, No. in sinus arrhythmia arterial blood pressure at interval in healthy November | Journal of Applied Physiology, Vol. No. mechanisms are for effects on frequency heart rate An approach in a healthy and a Journal of Vol. No. of Heart and in with January | Vol. No. during A of respiratory Vol. No. coupling by slow breathing can persist in normal Physiology & Neurobiology, Vol. of ventricular action in heart at respiratory rate and low October | Frontiers in Physiology, Vol. of for estimating the spectral of under respiration March | Journal of and Vol. No. using features from the respiration and the recorded with regulation of heart rate and the appearance of respiratory sinus arrhythmia: from Vol. and explain healthy heart rate and August | of the of Sciences, Vol. No. in the assessment of heart rate variability in July | Frontiers in Psychology, Vol. in short-term May | Frontiers in Physiology, Vol. Cardiovascular Variability a February rate variability at evidence of mechanisms at January | Vol. No. spectral analysis effects of January | Acta Vol. No. heart rate variability is related to the variability in the respiratory | Vol. No. of the sympatho-vagal in the of oscillations in the human cardiovascular February | Human Physiology, Vol. No. cardiac phase response human respiratory heart rate | Vol. No. and a for exploration of human
In recent years the metagenomics techniques have allowed to study composition and function of the intestinal microbiota. The microbiota is a new frontier of biomedical research to be explored and there is growing evidence of its fundamental health-promoting activity. The present review gives a synthetic overview on the characteristics and the role of the microbiota in the adult with particular reference to physiology, pathophysiology and relationships with the host and the environment.
The translation of new discoveries in medicine to clinical routine has never been easy. During the second half of the last century, thanks to the progress in chemistry, biochemistry and pharmacology, we have seen the development and the application of a large number of drugs and devices aimed at the treatment of symptoms, blocking unwanted pathways and, in the case of infectious diseases, fighting the micro-organisms responsible. However, we are facing, today, a dramatic change in the therapeutic approach to pathologies and diseases. Indeed, the challenge of the present and the next decade is to fully restore the physiological status of the diseased organism and to completely regenerate tissue and organs when they are so seriously affected that treatments cannot be limited to the repression of symptoms or to the repair of damage. This is being made possible thanks to the major developments made in basic cell and molecular biology, including stem cell science, growth factor delivery, gene isolation and transfection, the advances in bioengineering and nanotechnology, including development of new biomaterials, biofabrication technologies and use of bioreactors, and the big improvements in diagnostic tools and imaging of cells, tissues and organs. In today`s world, an enhancement of communication between multidisciplinary experts, together with the promotion of joint projects and close collaborations among scientists, engineers, industry people, regulatory agencies and physicians are absolute requirements for the success of any attempt to develop and clinically apply a new biological therapy or an innovative device involving the collective use of biomaterials, cells and/or bioactive molecules. “Frontiers in Bioengineering and Biotechnology” aspires to be a forum for all people involved in the process by bridging the gap too often existing between a discovery in the basic sciences and its clinical application. Frontiers in Bioengineering and Biotechnology is a member of the Committee on Publication Ethics.
The grand challenge to physiology, as was first described in an essay published in the inaugural issue of Frontiers in Physiology in 2010, remains to integrate function from molecules to intact organisms. In order to make sense of the vast volume of information derived from, and increasingly dependent upon, reductionist approaches, a greater emphasis must be placed on the traditional integrated and more holistic approaches developed by the scientists who gave birth to physiology as an intellectual discipline. Our understanding of physiological regulation has evolved over time from the Greek idea of body humors, through Claude Bernard's "milieu intérieur," to Walter Cannon's formulation of the concept of "homeostasis" and the application of control theory (feedback and feedforward regulation) to explain how a constant internal environment is achieved. Homeostasis has become the central unifying concept of physiology and is defined as a self-regulating process by which an organism can maintain internal stability while adjusting to changing external conditions. Homeostasis is not static and unvarying; it is a dynamic process that can change internal conditions as required to survive external challenges. It is also important to note that homeostatic regulation is not merely the product of a single negative feedback cycle but reflects the complex interaction of multiple feedback systems that can be modified by higher control centers. This hierarchical control and feedback redundancy results in a finer level of control and a greater flexibility that enables the organism to adapt to changing environmental conditions. The health and vitality of the organism can be said to be the end result of homeostatic regulation. An understanding of normal physiology is not possible without an appreciation of this concept. Conversely, it follows that disruption of homeostatic mechanisms is what leads to disease, and effective therapy must be directed toward re-establishing these homeostatic conditions. Therefore, it is the purpose of this essay to describe the evolution of our understanding of homeostasis and the role of physiological regulation and dysregulation in health and disease.
The current research topics in Frontiers of Physiology include “Training intensity, volume and recovery distribution among elite and recreational endura\nnce athletes” (Frontiers in Physiology,\n2016) and “Wearable Sensor Technology for Monitoring Training Load and Health in the Athletic Population” (Frontiers in Physiology, 2017). As editors of both of these topics, we would like to share some thoughts concerning (a) how they are fundamentally linked and (b) why we believe it is essential to have an all-day, 24-h integrative view to understand elite athletes’ responses to exercise.\nAthletes who train frequently each week schedule their training and off-training for days (i.e., microcycles, for example, tapering periods, blocks of t\nraining) to as long as months (i.e., macrocycles, for example, periods of preparation with different focuses or training camps) to ensure progressive adaptation and prevent fatigue, boredom, and injury. From this perspective, a fundamental goal is to distribute exercise and off-training effectively over a certain period of time (for example, one or several seasons) to achieve optimal adaptation.\nHere, we highlight the importance of an all-day, 24-h integrative perspective on training, emphasizing the fact that conditions outside training significantly modulate adaptation, thereby complicating analysis of the distribution of training intensity.
Biophotonics as a highly interdisciplinary frontier often requires the assistance of optical agents to control the light pathways in cells, tissues and living organisms for specific biomedical applications. Organic semiconducting materials (OSMs) composed of π-conjugated building blocks as the optically active components have recently emerged as a promising category of biophotonic agents. OSMs possess common features including excellent optical properties, good photostability and biologically benign composition. This review summarizes the recent progress in the development of OSMs based on small-molecule fluorophores, aggregation-induced emission (AIE) dyes and semiconducting oligomer/polymer nanoparticles (SONs/SPNs) for advanced biophotonic applications. OSMs have been exploited as imaging agents to transduce biomolecular interactions into second near-infrared fluorescence, chemiluminescence, afterglow or photoacoustic signals, enabling deep-tissue ultrasensitive imaging of biological tissues, disease biomarkers and physiological indexes. By fine-tuning the molecular structures, OSMs can also convert light energy into cytotoxic free radicals or heat, allowing for effective cancer phototherapy. Due to their instant light response and efficient light-harvesting properties, precise regulation of biological activities using OSMs as remote transducers has been demonstrated for protein ion channels, gene transcription and protein activation. In addition to highlighting OSMs as a multifunctional platform for a wide range of biomedical applications, current challenges and perspectives of OSMs in biophotonics are discussed.
Information security has become an important concern in healthcare systems, owing to the increasing prevalence of medical devices and the growing use of wearable and mobile computing platforms for health and lifestyle monitoring. The previous work in the area of health information security has largely focused on attacks on the wireless communication channel of medical devices, or on health data stored in online databases. In this paper, we pursue an entirely different angle to health information security, motivated by the insight that the human body itself is a rich source (acoustic, visual, and electromagnetic) of data. We propose a new class of information security attacks that exploit physiological information leakage, i.e., various forms of information that naturally leak from the human body, to compromise privacy. As an example, we demonstrate attacks that exploit acoustic leakage from the heart and lungs. The medical devices deployed within or on our bodies also add to natural sources of physiological information leakage, thereby increasing opportunities for attackers. Unlike previous attacks on medical devices, which target the wireless communication to/from them, we propose privacy attacks that exploit information leaked by the very operation of these devices. As an example, we demonstrate how the acoustic leakage from an insulin pump can reveal important information about its operation, such as the duration and dosage of insulin injection. Moreover, we show how an adversary can estimate blood pressure (BP) by capturing and processing the electromagnetic radiation of an ambulatory BP monitoring device.
BACKGROUND: Long term right ventricular pacing can have deleterious effects on left ventricular (LV) function. His bundle pacing (HBP), a novel procedure can probably circumvent this setback. We investigated if (1) HBP is associated with pacing induced LV dysfunction by using LV global longitudinal strain (GLS) and (2) intermediate term performance of the Select Secure (3830) lead in the His bundle location. This report is probably the first on HBP in the Indian population. METHODS: 61 patients, with normal LV ejection fraction (EF) with a guideline based indication for permanent pacing underwent a HBP pacemaker implantation using the His Select Secure 3830 lead; with lead guided mapping for locating the His bundle. The patients underwent GLS assessment; evaluation of the His lead parameters - sensing, impedance and capture thresholds immediately after implantation and at 6 months in addition to the standard follow up. RESULTS: At 6 month follow up, the average GLS did not show significant variation from baseline in patients requiring ventricular pacing more than 40% and was similar, irrespective of selective or non selective His bundle pacing. All the patients had stable pacemaker parameters - with little change in capture threshold, lead impedance or sensing of the His bundle lead - implying electrical and mechanical stability on intermediate term follow-up. CONCLUSION: HBP is a feasible procedure in the hands of an experienced operator, with stable lead performance. It does not appear to be associated with pacing mediated left ventricular dysfunction at intermediate term follow up. It should probably become the default method of permanent pacing.
Health care is one of the most exciting frontiers in data mining and machine learning. Successful adoption of electronic health records (EHRs) created an explosion in digital clinical data available for analysis, but progress in machine learning for healthcare research has been difficult to measure because of the absence of publicly available benchmark data sets. To address this problem, we propose four clinical prediction benchmarks using data derived from the publicly available Medical Information Mart for Intensive Care (MIMIC-III) database. These tasks cover a range of clinical problems including modeling risk of mortality, forecasting length of stay, detecting physiologic decline, and phenotype classification. We propose strong linear and neural baselines for all four tasks and evaluate the effect of deep supervision, multitask training and data-specific architectural modifications on the performance of neural models.
1. The main aim of the present review is to raise awareness of the molecular complexity of single skeletal muscle fibres from "normal" and "transforming" muscles, in recognition of the many types of hybrids that have been observed in vertebrate skeletal muscle. The data used to illustrate various points made in the review were taken from studies on mammalian (mostly rat) and amphibian muscles. 2. The review provides a brief overview of the pattern and extent of molecular heterogeneity in hybrid muscle fibres and of the methodological problems encountered when attempting to identify and characterize such fibres. Particular attention is given to four types of skeletal muscle hybrids: (i) myosin heavy chain (MHC) hybrids; (ii) mismatched MHC-myosin light chains (MLC) hybrids; (iii) mismatched MHC-regulatory protein hybrids; and (iv) hybrids containing mismatched MHC-sarcoplasmic reticulum protein isoforms. 3. Some of the current ideas regarding the functional significance, origin and cognitive value of hybrid fibres are examined critically.
Considerable progress has been made in the last decade in the engineering and construction of a number of artificial tissue types. These constructs are typically viewed from the perspective of possible sources for implant and transplant materials in the clinical arena. However, incorporation of engineered tissues, often referred to as three-dimensional (3D) cell culture, also offers the possibility for significant advancements in research for physiological genomics. These 3D systems more readily mimic the in vivo setting than traditional 2D cell culture, and offer distinct advantages over the in vivo setting for some organ systems. As an example, cardiac cells in 3D culture 1) are more accessible for siRNA studies, 2) can be engineered with specific cell types, and 3) offer the potential for high-throughput screening of gene function. Here the state-of-the-art is reviewed and the applications for engineered tissue in genomics research are proposed. The ability to use engineered tissue in combination with genomics creates a bridge between traditional cellular and in vivo studies that is critical to enabling the transition of genetic information into mechanistic understanding of disease processes.
Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
This wide-ranging book contains fascinating account of their research given at the 29th Congress of the International Union of Physiological Sciences in September 1983 by leading workers in many branches of physiology. The volume therefore presents a broad picture of the subject in a readable form. The articles range from a colourful account of the medical significance of Australian marsupials to the discovery of hormones in bacteria. Anti-hormones and their importance in certain forms of cancer and in fertility are discussed, as is the use of genetic engineering in relation to gene function and its possible use in treating human disease.
Physiology and evolutionary biology have developed as two separated disciplines, a separation that mirrored the hypothesis that the physiological and evolutionary processes could be decoupled. We argue that non-genetic inheritance shatters the frontier between physiology and evolution, and leads to the coupling of physiological and evolutionary processes to a point where there exists a continuum between accommodation by phenotypic plasticity and adaptation by natural selection. This approach is also profoundly affecting the definition of the concept of phenotypic plasticity, which should now be envisaged as a multi-scale concept. We further suggest that inclusive inheritance provides a quantitative way to help bridging infra-individual (i.e. physiology) with supra-individual (i.e. evolution) approaches, in a way that should help building the long sough inclusive evolutionary synthesis.
Over the past decade, there has been an unprecedented international focus on improved quality and availability of medical care, which has reignited interest in clinical automation and drawn researchers toward novel solutions in the field of physiological closed-loop control systems (PCLCs). Today, multidisciplinary groups of expert scientists, engineers, clinicians, mathematicians, and policy-makers are combining their knowledge and experience to develop both the next generation of PCLC-based medical equipment and a collaborative commercial/academic infrastructure to support this rapidly expanding frontier. In the following article, we provide a robust introduction to the various aspects of this growing field motivated by the recent and ongoing work supporting two leading technologies: the artificial pancreas (AP) and automated anesthesia. Following a brief high-level overview of the main concepts in automated therapy and some relevant tools from systems and control theory, we explore - separately - the developments, challenges, state-of-the-art, and probable directions for AP and automated anesthesia systems. We then close the review with a consideration of the common lessons gleaned from these ventures and the implications they present for future investigations and adjacent research.
Corals are fundamental ecosystem engineers, creating large, intricate reefs that support diverse and abundant marine life. At the core of a healthy coral animal is a dynamic relationship with microorganisms, including a mutually beneficial symbiosis with photosynthetic dinoflagellates (Symbiodinium spp.) and enduring partnerships with an array of bacterial, archaeal, fungal, protistan, and viral associates, collectively termed the coral holobiont. The combined genomes of this coral holobiont form a coral hologenome, and genomic interactions within the hologenome ultimately define the coral phenotype. Here we integrate contemporary scientific knowledge regarding the ecological, host-specific, and environmental forces shaping the diversity, specificity, and distribution of microbial symbionts within the coral holobiont, explore physiological pathways that contribute to holobiont fitness, and describe potential mechanisms for holobiont homeostasis. Understanding the role of the microbiome in coral resilience, acclimation, and environmental adaptation is a new frontier in reef science that will require large-scale collaborative research efforts.