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Circulatory physiology

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https://www.readbyqxmd.com/read/28529487/cardiac-baroreflex-variability-and-resetting-during-sustained-mild-effort
#1
Mair Zamir, Mark B Badrov, T Dylan Olver, J Kevin Shoemaker
This exploratory study assessed the pattern of closed-loop baroreflex resetting using multi-logistic-curve analysis. Operating point gain and ranges of RR-interval (RRI) and systolic blood pressure (SBP) are derived to examine how these relate to sympathetic activation. Sustained low-intensity isometric handgrip exercise, with a period of post-exercise circulatory occlusion (PECO), provided a model to study baroreflex resetting because the progression toward fatigue at constant tension induces a continuous increase in volitional contribution to neuro-cardiovascular control...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28512680/a-novel-idea-to-improve-cardiac-output-of-mechanical-circulatory-support-devices-by-optimizing-kinetic-energy-transfer-available-in-forward-moving-aortic-blood-flow
#2
Muhammad B Qureshi, Jacob Glower, Daniel L Ewert, Steven C Koenig
Mechanical circulatory support devices (MCSDs) have gained widespread clinical acceptance as an effective heart failure (HF) therapy. The concept of harnessing the kinetic energy (KE) available in the forward aortic flow (AOF) is proposed as a novel control strategy to further increase the cardiac output (CO) provided by MCSDs. A complete mathematical development of the proposed theory and its application to an example MCSDs (two-segment extra-aortic cuff) are presented. To achieve improved device performance and physiologic benefit, the example MCSD timing is regulated to maximize the forward AOF KE and minimize retrograde flow...
May 16, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28510504/cardiopulmonary-exercise-testing-basics-of-methodology-and-measurements
#3
Alessandro Mezzani
Cardiopulmonary exercise testing adds measurement of ventilation and volume of oxygen uptake and exhaled carbon dioxide to routine physiological and performance parameters obtainable from conventional exercise testing, furnishing an all-round vision of the systems involved in both oxygen transport from air to mitochondria and its utilization during exercise. Peculiarities of cardiopulmonary exercise testing methodology are the use of ramp protocols and calibration procedures for flow meters and gas analyzers...
May 16, 2017: Annals of the American Thoracic Society
https://www.readbyqxmd.com/read/28495270/egg-deposition-of-maternal-testosterone-is-primarily-controlled-by-the-preovulatory-peak-of-luteinizing-hormone-in-japanese-quail
#4
Monika Okuliarova, Simone L Meddle, Michal Zeman
Differential transfer of maternal testosterone (T) into egg yolk provides a means of adjusting an offspring's phenotype to ambient environmental conditions. While the environmental and genetic driven variability in yolk T levels is widely described, the underlying mechanisms are poorly understood. Here, we investigated whether neuroendocrine mechanisms controlling ovulatory processes are associated with the regulation of yolk T deposition. Circulatory profiles of luteinizing hormone (LH), T and estradiol levels were analysed during the last 7 h before ovulation in Japanese quail selected for contrasting yolk T concentrations...
May 8, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28482625/transepidermal-oxygen-flux-during-arterial-occlusion-using-ratiometric-luminescence-imaging
#5
M Ranieri, S Klein, A Kotrade, C Taeger, J D Dolderer, L Prantl, S Geis
BACKGROUND: A physiological oxygen transport through a circulatory and microcirculatory system is essential for execution of cellular functions. Several pathological conditions e.g. infections, ischemia, cancer, diabetes, hypertension or chronic wounds show a change of oxygen distribution and oxygen tension in cellular microenvironment. Additionally complex operative procedures in order to reconstruct tissue defects require a reliable monitoring of microcirculation. OBJECTIVE: Target of this study was to evaluate skin oxygenation during an ischemia-reperfusion experiment using transepidermal oxygen flux imaging...
May 2, 2017: Clinical Hemorheology and Microcirculation
https://www.readbyqxmd.com/read/28476893/bigger-is-not-better-cortisol-induced-cardiac-growth-and-dysfunction-in-salmonids
#6
Ida B Johansen, Erik Sandblom, Peter V Skov, Albin Gräns, Andreas Ekström, Ida G Lunde, Marco A Vindas, Lili Zhang, Erik Höglund, Michael Frisk, Ivar Sjaastad, Göran E Nilsson, Øyvind Øverli
Stress and elevated cortisol levels are associated with pathological heart growth and cardiovascular disease in humans and other mammals. We recently established a link between heritable variation in post-stress cortisol production and cardiac growth also in salmonid fish. A conserved stimulatory effect of the otherwise catabolic steroid hormone cortisol is likely implied, but has to date not been established experimentally. Furthermore, whereas cardiac growth is associated with failure of the mammalian heart, pathological cardiac hypertrophy has not previously been described in fish...
May 5, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28448528/minimally-invasive-estimation-of-ventricular-dead-space-volume-through-use-of-frank-starling-curves
#7
Shaun Davidson, Chris Pretty, Antoine Pironet, Thomas Desaive, Nathalie Janssen, Bernard Lambermont, Philippe Morimont, J Geoffrey Chase
This paper develops a means of more easily and less invasively estimating ventricular dead space volume (Vd), an important, but difficult to measure physiological parameter. Vd represents a subject and condition dependent portion of measured ventricular volume that is not actively participating in ventricular function. It is employed in models based on the time varying elastance concept, which see widespread use in haemodynamic studies, and may have direct diagnostic use. The proposed method involves linear extrapolation of a Frank-Starling curve (stroke volume vs end-diastolic volume) and its end-systolic equivalent (stroke volume vs end-systolic volume), developed across normal clinical procedures such as recruitment manoeuvres, to their point of intersection with the y-axis (where stroke volume is 0) to determine Vd...
2017: PloS One
https://www.readbyqxmd.com/read/28439697/heart-transplantation-for-adults-with-congenital-heart-disease-current-status-and-future-prospects
#8
REVIEW
Hikaru Matsuda, Hajime Ichikawa, Takayoshi Ueno, Yoshiki Sawa
Increased survival rates after corrective or palliative surgery for complex congenital heart disease (CHD) in infancy and childhood are now being coupled with increased numbers of patients who survive to adulthood with various residual lesions or sequelae. These patients are likely to deteriorate in cardiac function or end-organ function, eventually requiring lifesaving treatment including heart transplantation. Although early and late outcomes of heart transplantation have been improving for adult survivors of CHD, outcomes and pretransplant management could still be improved...
April 24, 2017: General Thoracic and Cardiovascular Surgery
https://www.readbyqxmd.com/read/28437389/normothermic-perfusion-in-the-assessment-and-preservation-of-declined-livers-before-transplantation-hyperoxia-and-vasoplegia-important-lessons-from-the-first-12-cases
#9
Christopher J E Watson, Vasilis Kosmoliaptsis, Lucy V Randle, Alexander E Gimson, Rebecca Brais, John R Klinck, Mazin Hamed, Anastasia Tsyben, Andrew J Butler
BACKGROUND: A program of normothermic ex situ liver perfusion (NESLiP) was developed to facilitate better assessment and use of marginal livers, while minimizing cold ischemia. METHODS: Declined marginal livers and those offered for research were evaluated. Normothermic ex situ liver perfusion was performed using an erythrocyte-based perfusate. Viability was assessed with reference to biochemical changes in the perfusate. RESULTS: Twelve livers (9 donation after circulatory death [DCD] and 3 from brain-dead donors), median Donor Risk Index 2...
May 2017: Transplantation
https://www.readbyqxmd.com/read/28412372/flavonoids-and-platelet-aggregation-a-brief-review
#10
REVIEW
Caterina Faggio, Antoni Sureda, Silvia Morabito, Ana Sanches Silva, Andrei Mocan, Seyed Fazel Nabavi, Seyed Mohammad Nabavi
Platelets are small anucleated fragments derived from a megakaryocyte precursor. Platelets play a key role in many physiological functions especially in hemostasis and wound healing processes in order to maintain the integrity of the circulatory system. In addition, activated platelets release cytokines and chemokines which modulate the immune response and, in some cases of hyperactivation, they could be associated to the pathogenesis of inflammatory diseases. Flavonoids are polyphenolic compounds ubiquosly found in plants known to be potent antioxidants with positive effects against diverse diseases such as cancer, neurodegenerative or cardiovascular disease...
April 12, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28407237/cytoskeletal-remodeling-and-regulation-of-cell-fate-in-the-hypertensive-neonatal-pulmonary-artery-in-response-to-stress
#11
REVIEW
Dina Johar
Neonatal pulmonary hypertension (PHN) is a lethal progressive disease that occurs in prenatal circulatory transition. Mechanical wall strain caused by cardiac pulsation integrates with hypoxia to generate rapidly progressive myocyte cytoskeleton disassembly and failure to exert force generation. The physiological responses to such an interaction have not been investigated. The persistent phenotype does not respond to traditional vasodilator therapy; hence, there is a need for new treatment strategies to improve the morbidity and mortality outcomes...
April 13, 2017: Journal of Cellular Physiology
https://www.readbyqxmd.com/read/28403066/non-hemodynamic-effects-of-catecholamines
#12
Clair Hartmann, Peter Radermacher, Martin Wepler, Benedikt Nubaum
Circulatory shock is defined as an imbalance between tissue oxygen supply and demand, and mostly results from a loss of blood volume, cardiac pump failure and/or reduction of vasomotor tone. The clinical hallmarks of circulatory shock are arterial hypotension and lactate acidosis. Since the degree and duration of hypotension are major determinants of outcome, vasopressor administration represents a cornerstone therapy to treat these patients. Current guidelines recommend the use of catecholamines as the drug of first choice...
April 11, 2017: Shock
https://www.readbyqxmd.com/read/28401917/cooperative-roles-of-the-suprachiasmatic-nucleus-central-clock-and-the-adrenal-clock-in-controlling-circadian-glucocorticoid-rhythm
#13
Sooyoung Chung, Eun Jeong Lee, Hyo Kyeong Cha, Jeongah Kim, Doyeon Kim, Gi Hoon Son, Kyungjin Kim
The mammalian circadian timing system consists of the central clock in the hypothalamic suprachiasmatic nucleus (SCN) and subsidiary peripheral clocks in other tissues. Glucocorticoids (GCs) are adrenal steroid hormones with widespread physiological effects that undergo daily oscillations. We previously demonstrated that the adrenal peripheral clock plays a pivotal role in circadian GC rhythm by driving cyclic GC biosynthesis. Here, we show that the daily rhythm in circulating GC levels is controlled by bimodal actions of central and adrenal clockwork...
April 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28389660/characteristics-of-the-heme-catabolic-pathway-in-mild-unconjugated-hyperbilirubinemia-and-their-associations-with-inflammation-and-disease-prevention
#14
Christine Mölzer, Marlies Wallner, Carina Kern, Anela Tosevska, René Zadnikar, Daniel Doberer, Rodrig Marculescu, Karl-Heinz Wagner
Heme catabolism exerts physiological functions that impact health through depressing inflammation. Upon reactive pathway progression, as in Gilbert's Syndrome (GS; UGT1A1*28 polymorphism), aggravated health effects have been determined. Based on lower inflammation and improved metabolic health reported for GS, inter-group differences in heme catabolism were explored. Therefore, a case-control study including 120 fasted, healthy, age- and gender matched subjects with/without GS, was conducted. Genetic expressions of HMOX-1 and BLVRA were measured...
April 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28388392/cardiogenic-shock-from-ecmo-to-impella-and-beyond
#15
REVIEW
Mehdi H Shishehbor, Nader Moazami, Michael Zhen-Yu Tong, Shinya Unai, W H Wilson Tang, Edward G Soltesz
For patients in cardiogenic shock, several devices can serve as a "bridge," ie, provide circulatory support and allow the patient to live long enough to recover or to receive a heart transplant or a long-term device. Options include an intra-aortic balloon pump, TandemHeart, Impella, extracorporeal membrane oxygenation (ECMO), and CentriMag. Which device to use depends on individual patient needs, local expertise, and anatomic and physiologic considerations.
April 2017: Cleveland Clinic Journal of Medicine
https://www.readbyqxmd.com/read/28378268/carbon-dioxide-poisoning-a-literature-review-of-an-often-forgotten-cause-of-intoxication-in-the-emergency-department
#16
REVIEW
Kris Permentier, Steven Vercammen, Sylvia Soetaert, Christian Schellemans
The goal of this article was to provide an overview of the literature available on carbon dioxide intoxication. Articles were included based on their focus on medical or physiological effects of carbon dioxide. Studies related to decompression sickness were excluded. Mechanisms of carbon dioxide poising (both as an asphyxiant and as a toxicant) were described. Our review suggested that precautions are needed when handling dry ice or while working in confined spaces. Pre-hospital responders also need to pay attention for the possible diagnosis of CO2 intoxication for their own safety...
December 2017: International Journal of Emergency Medicine
https://www.readbyqxmd.com/read/28375841/a-mock-heart-engineered-with-helical-aramid-fibers-for-in-vitro-cardiovascular-device-testing
#17
So-Hyun Jansen-Park, Po-Lin Hsu, Indra Müller, Ulrich Steinseifer, Dirk Abel, Rüdiger Autschbach, Rolf Rossaint, Thomas Schmitz-Rode
Mock heart circulation loops (MHCLs) serve as in-vitro platforms to investigate the physiological interaction between circulatory systems and cardiovascular devices. A mock heart (MH) engineered with silicone walls and helical aramid fibers, to mimic the complex contraction of a natural heart, has been developed to advance the MHCL previously developed in our group. A mock aorta with an anatomical shape enables the evaluation of a cannulation method for ventricular assist devices (VADs) and investigation of the usage of clinical measurement systems like pressure-volume catheters...
April 1, 2017: Biomedizinische Technik. Biomedical Engineering
https://www.readbyqxmd.com/read/28365652/interstage-home-monitoring-after-newborn-first-stage-palliation-for-hypoplastic-left-heart-syndrome-family-education-strategies
#18
Jo Ann Nieves, Karen Uzark, Nancy A Rudd, Jennifer Strawn, Anne Schmelzer, Nancy Dobrolet
Children born with hypoplastic left heart syndrome are at high risk for serious morbidity, growth failure, and mortality during the interstage period, which is the time from discharge home after first-stage hypoplastic left heart syndrome palliation until the second-stage surgical intervention. The single-ventricle circulatory physiology is complex, fragile, and potentially unstable. Multicenter initiatives have been successfully implemented to improve outcomes and optimize growth and survival during the interstage period...
April 2017: Critical Care Nurse
https://www.readbyqxmd.com/read/28344595/alpha-type-phospholipase-a2-inhibitors-from-snake-blood
#19
REVIEW
Norival A Santos-Filho, Claudia T Santos
It is of popular and scientific knowledge that toxins from snake venom (among them the PLA2 and myotoxins) are neutralized by various compounds, such as antibodies and proteins purified from animal blood. Venomous and nonvenomous snakes have PLA2 inhibitory proteins, called PLIs, in their blood serum. One hypothesis that could explain the presence of these PLIs in the serum of venomous snakes would be self-protection against the enzymes of their own venom, which eventually could reach the circulatory system...
2017: Journal of Venomous Animals and Toxins Including Tropical Diseases
https://www.readbyqxmd.com/read/28343276/an-updated-review-of-cardiac-devices-in-heart-failure
#20
REVIEW
C Murphy, H Zafar, F Sharif
BACKGROUND: Heart failure has the highest rates of adult hospitalisations, the highest mortality rates and significant costs associated with its care. The cost of heart failure is expected continue to grow on a global scale, with $108 billion spent on heart failure in 2012. Mortality rates are high, with incident cases of heart failure resulting in 30% 1-year mortality, and in hospital mortality of acute heart failure, 28%. METHODS AND RESULTS: This article reviews the devices currently in use for the treatment of heart failure, as well as those that are under investigation...
March 25, 2017: Irish Journal of Medical Science
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