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https://www.readbyqxmd.com/read/28346013/the-physiology-of-blood-loss-and-shock-new-insights-from-a-human-laboratory-model-of-hemorrhage
#1
Alicia M Schiller, Jeffrey T Howard, Victor A Convertino
The ability to quickly diagnose hemorrhagic shock is critical for favorable patient outcomes. Therefore, it is important to understand the time course and involvement of the various physiological mechanisms that are active during volume loss and that have the ability to stave off hemodynamic collapse. This review provides new insights about the physiology that underlies blood loss and shock in humans through the development of a simulated model of hemorrhage using lower body negative pressure. In this review, we present controlled experimental results through utilization of the lower body negative pressure human hemorrhage model that provide novel insights on the integration of physiological mechanisms critical to the compensation for volume loss...
April 2017: Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28345766/%C3%AE-linolenic-acid-and-exercise-training-independently-and-additively-decreases-blood-pressure-and-prevents-diastolic-dysfunction-in-obese-zucker-rats
#2
Pierre-Andre Barbeau, Tanya M Holloway, Jamie Whitfield, Brittany Baechler, Joe Quadrilatero, Luc J C van Loon, Adrian Chabowski, Graham P Holloway
While α-linolenic acid (ALA) and endurance exercise training independently attenuate hyperlipidemia-related cardiovascular derangements, there is a paucity of information pertaining to their mechanisms-of-action and efficacy when combined as a preventative therapeutic approach. Therefore, we used obese Zucker rats to investigate the independent and combined effects of these interventions on cardiovascular disease. Specifically, animals were randomly assigned to one of the following: control diet-sedentary (C-Sed), ALA supplemented-sedentary (ALA-Sed), control diet-exercise trained (C-Ex), or ALA supplemented-exercise trained (ALA-Ex)...
March 27, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28345212/cardiac-iodine-123-metaiodobenzylguanidine-scintigraphy-may-be-useful-to-identify-pathologic-from-physiologic-sinus-bradycardia
#3
Akihiro Sunaga, Masaharu Masuda, Masashi Fujita, Osamu Iida, Takashi Kanda, Yasuhiro Matsuda, Takakazu Morozumi, Toshiaki Mano, Masaaki Uematsu
BACKGROUND: Sinus bradycardia includes pathologic sick sinus syndrome (SSS) and physiologic bradycardia such as athletes' heart. Pacemaker implantation is indicated for patients with symptomatic SSS; however, the indication remains difficult to determine in those with mild and/or unspecific symptoms. The sympathetic tone is increased in response to reduced cardiac output in SSS, whereas excessive vagal tone has been seen in physiological bradycardia. We sought to determine if cardiac iodine-123-metaiodobenzylguanidine scintigraphy ((123) I-MIBG) was useful in differentiating pathologic from physiologic sinus bradycardia...
March 27, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/28343439/toward-improved-myocardial-maturity-in-an-organ-on-chip-platform-with-immature-cardiac-myocytes
#4
Sean P Sheehy, Anna Grosberg, Pu Qin, David J Behm, John P Ferrier, Mackenzie A Eagleson, Alexander P Nesmith, David Krull, James G Falls, Patrick H Campbell, Megan L McCain, Robert N Willette, Erding Hu, Kevin K Parker
In vitro studies of cardiac physiology and drug response have traditionally been performed on individual isolated cardiomyocytes or isotropic monolayers of cells that may not mimic desired physiological traits of the laminar adult myocardium. Recent studies have reported a number of advances to Heart-on-a-Chip platforms for the fabrication of more sophisticated engineered myocardium, but cardiomyocyte immaturity remains a challenge. In the anisotropic musculature of the heart, interactions between cardiac myocytes, the extracellular matrix (ECM), and neighboring cells give rise to changes in cell shape and tissue architecture that have been implicated in both development and disease...
January 1, 2017: Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28342708/hemodynamic-phenotyping-based-on-exercise-catheterization-predicts-outcome-in-patients-with-heart-failure-and-reduced-ejection-fraction
#5
Andreas Rieth, Manuel Jonas Richter, Henning Gall, Werner Seeger, Hossein A Ghofrani, Veselin Mitrovic, Christian W Hamm
BACKGROUND: Exercise right heart catheterization (RHC) unmasks different phenotypes based on hemodynamic response to exertion in patients with heart failure. The prognostic relevance of this approach in patients with heart failure and reduced ejection fraction (HFrEF) is uncertain. METHODS: We analyzed 167 patients with HFrEF from the Kerckhoff-Klinik Heart Failure Registry who underwent supine exercise RHC with constant external workload between September 2009 and August 2014...
February 28, 2017: Journal of Heart and Lung Transplantation
https://www.readbyqxmd.com/read/28342705/comparison-of-20-mannitol-and-3-hypertonic-saline-on-intracranial-pressure-and-systemic-hemodynamics
#6
Navdeep Sokhal, Girija Prasad Rath, Arvind Chaturvedi, Manmohan Singh, Hari Hara Dash
Mannitol and hypertonic saline (HS) are most commonly used hyperosmotic agents for intraoperative brain relaxation. We compared the changes in ICP and systemic hemodynamics after infusion of equiosmolar solutions of both agents in patients undergoing craniotomy for supratentorial tumors. Forty enrolled adults underwent a standard anesthetic induction. Apart from routine monitoring parameters, subdural ICP with Codmann catheter and cardiac indices by Vigileo monitor, were recorded. The patients were randomized to receive equiosmolar solutions of either 20% mannitol (5ml/kg) or 3% HS (5...
March 22, 2017: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
https://www.readbyqxmd.com/read/28341635/sept7b-is-required-for-the-subcellular-organization-of-cardiomyocytes-and-cardiac-function-in-zebrafish
#7
Surjya Narayan Dash, Suneeta Narumanchi, Jere Paavola, Sanni Perttunen, Hong Wang, Päivi Lakkisto, Ilkka Tikkanen, Sanna Lehtonen
Myofibrils made up of actin and myosin and associated proteins generate the contractile force in muscle and consequently, mutations in these proteins may lead to heart failure. Septins are a conserved family of small GTPases that associate with actin filaments, microtubules and cellular membranes. Despite the importance of septins in cytoskeleton organization, their role in cardiomyocyte organization and function is poorly characterized. Here we show that septin 7 is expressed in both embryonic and adult zebrafish heart, and elucidate the physiological significance of sept7b, the zebrafish ortholog of human septin 7, in the heart in embryonic and larval zebrafish...
March 24, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28338768/integrative-blood-pressure-response-to-upright-tilt-post-renal-denervation
#8
Erin J Howden, Cara East, Justin S Lawley, Abigail S L Stickford, Myrthe Verhees, Qi Fu, Benjamin D Levine
BACKGROUND: Whether renal denervation (RDN) in patients with resistant hypertension normalizes blood pressure (BP) regulation in response to routine cardiovascular stimuli such as upright posture is unknown. We conducted an integrative study of BP regulation in patients with resistant hypertension who had received RDN to characterize autonomic circulatory control. METHODS: Twelve patients (60 ± 9 [SD] years, n = 10 males) who participated in the Symplicity HTN-3 trial were studied and compared to 2 age-matched normotensive (Norm) and hypertensive (unmedicated, HTN) control groups...
February 20, 2017: American Journal of Hypertension
https://www.readbyqxmd.com/read/28338595/3-0-nacl-adenosine-lidocaine-mg-2-alm-bolus-and-4-hours-drip-infusion-reduces-non-compressible-hemorrhage-by-60-in-a-rat-model
#9
Hayley L Letson, Geoffrey P Dobson
BACKGROUND: Noncompressible torso hemorrhage is the leading cause of potentially survivable trauma in far-forward combat environments. Our aim was to examine the effect of small-volume 3% NaCl adenosine, lidocaine and Mg (ALM) bolus and 0.9% NaCl/ALM 'drip' on survivability and cardiac/gut/kidney function in a rat model of hepatic hemorrhage and shock. METHODS: Male Sprague-Dawley rats (428±4 g) were anesthetized and randomly assigned to one of five groups (n=16): 1) Sham, 2) No Treatment, 3) Saline controls, 4) ALM therapy and 5) Hextend®...
March 23, 2017: Journal of Trauma and Acute Care Surgery
https://www.readbyqxmd.com/read/28338477/osmotic-and-hemodynamic-effects-of-hypertonic-glucose-during-hemodialysis
#10
Daniel Schneditz, Stanisław Niemczyk, Notburga Sauseng, Isolde Bachler, Edda Zierler, Helmut Karl Lackner, Hildegard Hafner-Giessauf
It was the purpose to quantify the hemodynamic effects of a bolus of hypertonic glucose injected into the extracorporeal system in a group of stable and non-diabetic patients during hemodialysis (HD).Glucose and electrolytes were measured in frequent intervals. Arterial blood pressures and heart rates were continuously recorded by non-invasive vascular unloading technique. Beat-to-beat stroke volume, cardiac output, and total peripheral resistance were determined by Modelflow method. Relative blood volumes were continuously measured by ultrasonic and optical means...
March 22, 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/28337701/ct-guided-drainage-of-pericardial-effusion-after-open-cardiac-surgery
#11
Nour-Eldin Abdelrehim Nour-Eldin, Mohammed Alsubhi, Tatjana Gruber-Rouh, Thomas J Vogl, Benjamin Kaltenbach, Hazem Hamed Soliman, Wael Eman Hassan, Sherif Maher Abolyazid, Nagy N Naguib
PURPOSE: This study was designed to evaluate the safety and efficacy of CT-guided drainage of the pericardial effusion in patients after cardiac surgery. MATERIALS AND METHODS: The study included 128 consecutive patients (82 males, 46 females; mean age 66.6 years, SD: 4.2) complicated by pericardial effusion or hemopericardium after cardiac surgeries between June 2008 and June 2016. The medical indication for therapeutic pericardiocentesis in all patients was hemodynamic instability caused by pericardial effusion...
March 23, 2017: Cardiovascular and Interventional Radiology
https://www.readbyqxmd.com/read/28336819/fundamental-hemodynamic-mechanisms-mediating-the-response-to-myocardial-ischemia-in-conscious-paraplegic-mice-cardiac-output-versus-peripheral-resistance
#12
Heidi L Lujan, Stephen E DiCarlo
Autonomic dysfunction, a relative sedentary lifestyle, a reduced muscle mass and increased adiposity leads to metabolic abnormalities that accelerate the development of coronary artery disease (CAD) in individuals living with spinal cord injury (SCI). An untoward cardiac incident is related to the degree of CAD, suggesting that the occurrence of a significant cardiac event is significantly higher for individuals with SCI Thus, understanding the fundamental hemodynamic mechanisms mediating the response to myocardial ischemia has the potential to positively impact individuals and families living with SCI Accordingly, we systematically investigated if thoracic level 5 spinal cord transection (T5X; paraplegia) alters the arterial blood pressure response to coronary artery occlusion and if the different arterial blood pressure responses to coronary artery occlusion between intact and paraplegic mice are mediated by changes in cardiac output and or systemic peripheral resistance and whether differences in cardiac output are caused by changes in heart rate and or stroke volume...
March 2017: Physiological Reports
https://www.readbyqxmd.com/read/28336538/effects-of-dobutamine-on-intestinal-microvascular-blood-flow-heterogeneity-and-oxygen-extraction-during-septic-shock
#13
Gustavo Adolfo Ospina-Tascón, Alberto Federico García Marín, Gabriel J Echeverri, William Fernando Bermúdez, Humberto José Madriñán Navia, Juan David Valencia, Edgardo Quiñones, Fernando Rodríguez, Angela Marulanda, César Augusto Arango Davila, Alejandro Bruhn, Glenn Hernández, Daniel De Backer
Derangements of microvascular blood flow distribution might contribute to disturbing oxygen extraction by peripheral tissues. We evaluated the dynamic relationships between the mesenteric oxygen extraction ratio (mes-ERO2) and the heterogeneity of microvascular blood flow at the gut and sublingual mucosa, during the development and resuscitation of septic shock in a swine model of fecal peritonitis. Jejunal-villi and sublingual microcirculation were evaluated using a portable intravital-microscopy technique...
March 23, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28336536/the-effect-of-aging-and-cardiorespiratory-fitness-on-the-lung-diffusing-capacity-response-to-exercise-in-healthy-humans
#14
Kirsten E Coffman, Alex R Carlson, Andrew D Miller, Bruce D Johnson, Bryan Joseph Taylor
Aging is associated with deterioration in the structure and function of the pulmonary circulation. We characterized the lung diffusing capacity for carbon monoxide (DLCO), alveolar-capillary membrane conductance (DmCO), and pulmonary-capillary blood volume (VC) response to discontinuous incremental exercise at 25, 50, 75, and 90% of peak work (Wpeak) in four groups: 1) Young [27 ± 3 y, maximal oxygen consumption (V̇O2max) 110 ± 18% age-predicted]; 2) Young Highly-Fit (27 ± 3 y, V̇O2max 147 ± 8% age-predicted); 3) Old (69 ± 5 y, V̇O2max 116 ± 13% age-predicted); and 4) Old Highly-Fit (65 ± 5 y, V̇O2max 162 ± 18% age-predicted)...
March 23, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28335844/heart-failure-induced-brain-injury
#15
REVIEW
Ofer Havakuk, Kevin S King, Luanda Grazette, Andrew J Yoon, Michael Fong, Noa Bregman, Uri Elkayam, Robert A Kloner
Heart failure (HF) is a systemic illness with grave implications for bodily functions. The brain, among other vital organs, often suffers insults as a result of HF, and both anatomic and functional brain abnormalities were found in the HF population. This injury was demonstrated across a wide range of clinical conditions and cardiac functions and was shown to affect patients' outcomes. Although reduced cardiac output and high burden of cardiovascular risk factors are the prevailing explanations for these findings, there are data showing the involvement of neurohormonal, nutritional, and inflammatory mechanisms in this complex process...
March 28, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28333321/preconception-and-early-pregnancy-maternal-haemodynamic-changes-in-healthy-women-in-relation-to-pregnancy-viability
#16
F L Foo, A Collins, C M McEniery, P R Bennett, I B Wilkinson, C C Lees
STUDY QUESTION: Are there differences in preconception cardiovascular function between women who have a viable pregnancy and those who have a first trimester miscarriage? SUMMARY ANSWER: Preconception cardiovascular function of central haemodynamics and arterial function are similar between women who have a viable pregnancy and those who have a first trimester miscarriage. WHAT IS KNOWN ALREADY: Miscarriages have been associated with increased long-term cardiovascular disease risk, and arterial and cardiovascular dysfunction has been hypothesised as the common link...
March 16, 2017: Human Reproduction
https://www.readbyqxmd.com/read/28330969/influence-of-the-coronary-circulation-on-thermal-tolerance-and-cardiac-performance-during-warming-in-rainbow-trout
#17
Andreas Ekström, Michael Axelsson, Albin Gräns, Jeroen Brijs, Erik Sandblom
Thermal tolerance in fish may be related to an oxygen limitation of cardiac function. While the hearts of some fish species receive oxygenated blood via a coronary circulation, the influence of this oxygen supply on thermal tolerance and cardiac performance during warming remain unexplored. Here, we analyzed the effect in vivo of acute warming on coronary blood flow in adult sexually mature rainbow trout (Onchorhynchus mykiss), and the consequences of chronic coronary ligation on cardiac function and thermal tolerance in juvenile trout...
February 22, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
https://www.readbyqxmd.com/read/28329460/model-based-comparison-of-the-normal-and-fontan-circulatory-systems-part-iii
#18
Raymond L Watrous, Alvin J Chin
BACKGROUND: For patients with the Fontan circulatory arrangement, angiotensin-converting enzyme inhibition, guanylate cyclase activation, phosphodiesterase 5 inhibition, and endothelin receptor antagonism have so far resulted in little or no improvement in [Formula: see text] or peak cardiac index (CI), suggesting that our understanding of the factors that most impact the exercise hemodynamics is incomplete. METHODS: To facilitate comparisons with clinical reports of the exercise performance of preadolescent Fontan patients, we rescaled our previously reported computational models of a two-year-old normal child and similarly aged Fontan patient, extended our Fontan model to capture the nonlinear relationship between flow and resistance quantified from previous computational fluid dynamic analyses of the total cavopulmonary connection (TCPC), and added respiration as well as skeletal muscle contraction...
March 2017: World Journal for Pediatric & Congenital Heart Surgery
https://www.readbyqxmd.com/read/28329138/small-intestinal-submucosa-tricuspid-valve-tube-graft-shows-growth-potential-remodelling-and-physiological-valve-function-in-a-porcine-model%C3%A2
#19
Diana M Ropcke, Christine Ilkjaer, Marcell J Tjornild, Soren N Skov, Steffen Ringgaard, Vibeke E Hjortdal, Sten L Nielsen
OBJECTIVES: Tricuspid valve reconstruction using small intestinal submucosal extracellular matrix (ECM) designed as a tube graft is possible in severe valve pathology. Using cardiac magnetic resonance imaging (MRI) and digital photograph imaging, valves were evaluated after 6 months in a porcine model. METHODS: Ten 60 kg pigs received a tricuspid valve tube graft. A baseline MRI was performed after 2 weeks ( n  = 8). A follow-up MRI was performed in three of five 6 months' survivors to assess function and haemodynamics of the tricuspid tube graft...
February 27, 2017: Interactive Cardiovascular and Thoracic Surgery
https://www.readbyqxmd.com/read/28328758/posttransfusion-increase-of-hematocrit-per-se-does-not-improve-circulatory-oxygen-delivery-due-to-increased-blood-viscosity
#20
Robert Zimmerman, Amy G Tsai, Beatriz Y Salazar Vázquez, Pedro Cabrales, Axel Hofmann, Jens Meier, Aryeh Shander, Donat R Spahn, Joel M Friedman, Daniel M Tartakovsky, Marcos Intaglietta
BACKGROUND: Blood transfusion is used to treat acute anemia with the goal of increasing blood oxygen-carrying capacity as determined by hematocrit (Hct) and oxygen delivery (DO2). However, increasing Hct also increases blood viscosity, which may thus lower DO2 if the arterial circulation is a rigid hydraulic system as the resistance to blood flow will increase. The net effect of transfusion on DO2 in this system can be analyzed by using the relationship between Hct and systemic blood viscosity of circulating blood at the posttransfusion Hct to calculate DO2 and comparing this value with pretransfusion DO2...
March 21, 2017: Anesthesia and Analgesia
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