Human Molecular and Physiological Responses to Hypoxia PDF Download
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Author: Sandro Malacrida
Publisher: Frontiers Media SA
ISBN: 2889762122
Category : Science
Languages : en
Pages : 111
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Book Description
Author: Sandro Malacrida
Publisher: Frontiers Media SA
ISBN: 2889762122
Category : Science
Languages : en
Pages : 111
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Book Description
Author: Hoi I Cheong
Publisher:
ISBN:
Category : Anoxemia
Languages : en
Pages : 106
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Book Description
Life-sustaining responses to hypoxia rely on the transcription factor, Hypoxia Inducible Factor-1 (HIF-1). Under hypoxia, HIF-1 accumulates and regulates multifaceted cellular responses. However, many underlying mechanisms of HIF-1 regulation are incompletely understood. Previous studies suggest a link between HIF-1 and beta-adrenergic receptors (ßAR). Here, we interrogated the role of ßARs in hypoxia responses by ß-blocker treatment of mice with hypoxia-inducible erythropoiesis. ß-blocker suppressed renal accumulation of HIF-1a, erythropoietin production and the generation of erythroid progenitor cells. Likewise, ß-blocker treatment of human endothelial cells attenuated HIF-1a accumulation and binding to target genes under hypoxia, and subsequent downstream gene expression. Consistently, ß-agonist increased HIF-1a accumulation in a dose- and time-dependent manner, an effect that was blocked by both ß1- and ß2-blockers, indicating a general property of this receptor class. ßAR signal transduction involves cyclic adenosine monophosphate (cAMP)-activated protein kinase A (PKA) and G protein-coupled receptor kinases (GRK). Direct activation of cAMP/ PKA pathways did not increase HIF-1a accumulation, and inhibition of PKA did not suppress HIF-1a by hypoxia. In contrast, pharmacological inhibition of GRK, or genetic mutation of ßAR that impairs GRK phosphorylation, blocked hypoxia-mediated HIF-1a accumulation. Mass spectrometry analyses revealed a unique hypoxia ßAR phosphorylation barcode different from the classical agonist. These findings identify an unknown role of ßAR in hypoxia responses. Another determinant of HIF-1 regulation is nitric oxide, a potent vasodilator. A natural experiment of genetically similar Ethiopians at high altitude (>3000 m), the Amhara and Oromo, revealed a dampened hemoglobin response in Amhara compared to Oromo. We hypothesized that Amhara highlanders offset their dampened hemoglobin response with the vascular nitric oxide response. We identified high levels of urinary nitrate and its bioactive signal molecule cyclic guanosine monophosphate (cGMP) in high-altitude Amhara, but not Oromo. Consistently, high-altitude Amhara have lower diastolic blood pressure than Oromo, an indicator of vasomotor tone. Both Amhara and Oromo maintained the amount of oxyhemoglobin at high altitudes, but the high-altitude Oromo suffered a much higher deoxyhemoglobin level. In conclusion, high-altitude Amhara offset a dampened hemoglobin response with the vasodilatory nitric oxide, whereas the Oromo mount a bigger hemoglobin response at the cost of circulating deoxyhemoglobin.
Author: Robert C. Roach
Publisher: Springer
ISBN: 1489976787
Category : Medical
Languages : en
Pages : 765
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Book Description
The latest in a series of books from the International Hypoxia Symposia, this volume spans reviews on key topics in hypoxia, and abstracts from poster and oral presentations. The biannual International Hypoxia Symposia are dedicated to hosting the best basic scientific and clinical minds to focus on the integrative and translational biology of hypoxia. Long before ‘translational medicine’ was a catchphrase, the founders of the International Hypoxia Symposia brought together basic scientists, clinicians and physiologists to live, eat, ski, innovate and collaborate in the Canadian Rockies. This collection of reviews and abstracts is divided into six sections, each covering new and important work relevant to a broad range of researchers interested in how humans adjust to hypoxia, whether on the top of Mt. Everest or in the pulmonary or cardiology clinic at low altitude. The sections include: Epigenetic Variations in Hypoxia High Altitude Adaptation Hypoxia and Sleep Hypoxia and the Brain Molecular Oxygen Sensing Physiological Responses to Hypoxia
Author: Rodrigo Iturriaga
Publisher: Frontiers Media SA
ISBN: 2889638006
Category :
Languages : en
Pages : 387
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Book Description
The appearance of photosynthetic organisms about 3 billion years ago increased the partial pressure of oxygen (PO2) in the atmosphere and enabled the evolution of organisms that use glucose and oxygen to produce ATP by oxidative phosphorylation. Hypoxia is commonly defined as the reduced availability of oxygen in the tissues produced by different causes, which include reduction of atmospheric PO2 as in high altitude, and secondary to pathological conditions such as sleep breathing and pulmonary disorders, anemia, and cardiovascular alterations leading to inadequate transport, delivery, and exchange of oxygen between capillaries and cells. Nowadays, it has been shown that hypoxia plays an important role in the genesis of several human pathologies including cardiovascular, renal, myocardial and cerebral diseases in fetal, young and adult life. Several mechanisms have evolved to maintain oxygen homeostasis. Certainly, all cells respond and adapt to hypoxia, but only a few of them can detect hypoxia and initiate a cascade of signals intended to produce a functional systemic response. In mammals, oxygen detection mechanisms have been extensively studied in erythropoietin-producing cells, chromaffin cells, bulbar and cortical neurons, pulmonary neuroepithelial cells, smooth muscle cells of pulmonary arteries, and chemoreceptor cells. While the precise mechanism underpinning oxygen, sensing is not completely known several molecular entities have been proposed as possible oxygen sensors (i.e. Hem proteins, ion channels, NADPH oxidase, mitochondrial cytochrome oxidase). Remarkably, cellular adaptation to hypoxia is mediated by the master oxygen-sensitive transcription factor, hypoxia-inducible factor-1, which can induce up-regulation of different genes to cope the cellular effects related to a decrease in oxygen levels. Short-term responses to hypoxia included mainly chemoreceptor-mediated reflex ventilatory and hemodynamic adaptations to manage the low oxygen concentration while more prolonged exposures to hypoxia can elicit more sustained physiological responses including switch from aerobic to anaerobic metabolism, vascularization, and enhancement of blood O2 carrying capacity. The focus of this research topic is to provide an up-to-date vision on the current knowledge on oxygen sensing mechanism, physiological responses to acute or chronic hypoxia and cellular/tissue/organ adaptations to hypoxic environment.
Author: Peter L. Lutz
Publisher: Landes Bioscience
ISBN:
Category : Medical
Languages : en
Pages : 224
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Book Description
Research for clinicians and researchers in neurology. New material on the mechanism of brain hypoxia tolerance in some vertebrate species.
Author: Elena Loreti
Publisher: MDPI
ISBN: 3036501487
Category : Science
Languages : en
Pages : 288
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Book Description
Molecular oxygen deficiency leads to altered cellular metabolism and can dramatically reduce crop productivity. Nearly all crops are negatively affected by a lack of oxygen (hypoxia) due to adverse environmental conditions such as excessive rain and soil waterlogging. Extensive efforts to fully understand how plants sense oxygen deficiency and their ability to respond using different strategies are crucial to increase hypoxia tolerance. Progress in our understanding has been significant in recent years. This topic certainly deserves more attention from the academic community; therefore, we have compiled a series of articles reflecting the advancements made thus far.
Author:
Publisher: Elsevier
ISBN: 0080497195
Category : Science
Languages : en
Pages : 867
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Book Description
The ability of cells to sense and respond to changes in oxygenation underlies a multitude of developmental, physiological, and pathological processes. This volume provides a comprehensive compendium of experimental approaches to the study of oxygen sensing in 48 chapters that are written by leaders in their fields.
Author: Roland N. Pittman
Publisher: Biota Publishing
ISBN: 1615047212
Category : Medical
Languages : en
Pages : 117
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Book Description
This presentation describes various aspects of the regulation of tissue oxygenation, including the roles of the circulatory system, respiratory system, and blood, the carrier of oxygen within these components of the cardiorespiratory system. The respiratory system takes oxygen from the atmosphere and transports it by diffusion from the air in the alveoli to the blood flowing through the pulmonary capillaries. The cardiovascular system then moves the oxygenated blood from the heart to the microcirculation of the various organs by convection, where oxygen is released from hemoglobin in the red blood cells and moves to the parenchymal cells of each tissue by diffusion. Oxygen that has diffused into cells is then utilized in the mitochondria to produce adenosine triphosphate (ATP), the energy currency of all cells. The mitochondria are able to produce ATP until the oxygen tension or PO2 on the cell surface falls to a critical level of about 4–5 mm Hg. Thus, in order to meet the energetic needs of cells, it is important to maintain a continuous supply of oxygen to the mitochondria at or above the critical PO2 . In order to accomplish this desired outcome, the cardiorespiratory system, including the blood, must be capable of regulation to ensure survival of all tissues under a wide range of circumstances. The purpose of this presentation is to provide basic information about the operation and regulation of the cardiovascular and respiratory systems, as well as the properties of the blood and parenchymal cells, so that a fundamental understanding of the regulation of tissue oxygenation is achieved.
Author: Robert C. Roach
Publisher: Springer Science & Business Media
ISBN: 9780306466960
Category : Medical
Languages : en
Pages : 466
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Book Description
Hypoxia remains a constant threat throughout life. It is for this reason that the International Hypoxia Society strives to maintain a near quarter century tradition of presenting a stimulating blend of clinical and basic science discussions. International experts from many fields have focused on the state-of-the-art discoveries in normal and pathophysiological responses to hypoxia. Topics in this volume include gene-environment interactions, a theme developed in both a clinical context regarding exercise and hypoxia, as well as in native populations living in high altitudes. Furthermore, experts in the field have combined topics such as skeletal muscle angiogenesis and hypoxia, high altitude pulmonary edema, new insights into the biology of the erythropoietin receptor, and the latest advances in cardiorespiratory control in hypoxia. This volume explores the fields of anatomy, cardiology, biological transport, and biomedical engineering among many others.
Author: Lei Xi
Publisher: Springer Science & Business Media
ISBN: 1447129067
Category : Medical
Languages : en
Pages : 310
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Book Description
Intermittent hypoxia can cause significant structural and functional impact on the systemic, organic, cellular and molecular processes of human physiology and pathophysiology. This book focuses on the most updated scientific understanding of the adaptive (beneficial) and maladaptive (detrimental) responses to intermittent hypoxia and their potential pathogenetic or prophylactic roles in the development and progression of major human diseases. This is a comprehensive monograph for clinicians, research scientists, academic faculty, postgraduate and medical students, and allied health professionals who are interested in enhancing their up-to-date knowledge of intermittent hypoxia research and its translational applications in preventing and treating major human diseases.
