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Blood flow restriction

Walter H Reinhart
The hematocrit (Hct) determines the oxygen carrying capacity of blood, but also increases blood viscosity and thus flow resistance. From this dual role the concept of an optimum Hct for tissue oxygenation has been derived. Viscometric studies using the ratio Hct/blood viscosity at high shear rate showed an optimum Hct of 50-60% for red blood cell (RBC) suspensions in plasma. For the perfusion of an artificial microvascular network with 5-70μm channels the optimum Hct was 60-70% for high driving pressures. With lower shear rates or driving pressures the optimum Hct shifted towards lower values...
October 21, 2016: Clinical Hemorheology and Microcirculation
Cori R Atlin, Christoph Haller, Osami Honjo, Anusha Jegatheeswaran, Glen S Van Arsdell
BACKGROUND: Size mismatch between body and a systemic-to-pulmonary shunt can result in excessive pulmonary blood flow, compromising systemic oxygen delivery. Previously reported techniques to mechanically restrict shunt flow lack precision and reproducibility. We developed a formula for shunt banding and assessed its efficacy and reproducibility by in vitro and clinical measurements. METHODS: Formulas to determine diameter reduction, length of banding, and effect on the ratio of pulmonary blood flow (Qp) to systemic blood flow (Qs) were established...
November 2016: Journal of Thoracic and Cardiovascular Surgery
David J Tennent, Christina M Hylden, Anthony E Johnson, Travis C Burns, Jason M Wilken, Johnny G Owens
INTRODUCTION: Quadriceps strength after arthroscopic knee procedures is frequently diminished several years postoperation. Blood flow restriction (BFR) training uses partial venous occlusion while performing submaximal exercise to induce muscle hypertrophy and strength improvements. The purpose of this study was to evaluate BFR as a postoperative therapeutic intervention after knee arthroscopy. METHODS: A randomized controlled pilot study comparing physical therapy with and without BFR after knee arthroscopy was conducted...
October 5, 2016: Clinical Journal of Sport Medicine: Official Journal of the Canadian Academy of Sport Medicine
Fuyou Liang, Xiaosheng Liu, Ryuhei Yamaguchi, Hao Liu
Recent studies raised increasing concern about the reliability of computer models in reproducing in vivo hemodynamics in cerebral aneurysms. Boundary condition problem is among the most frequently addressed issues since three-dimensional (3-D) modeling is usually restricted to local arterial segments. The present study focused on aneurysms on the anterior communicating artery (ACoA) which represent a large subgroup of detected cerebral aneurysms and, in particular, have a relatively high risk of rupture compared to aneurysms located in other regions...
October 6, 2016: Journal of Biomechanics
Puja Dudeja, Apoorva Sindhu, Pooja Shankar, Tukaram Gadekar
INTRODUCTION: Reproductive health of adolescent girls is crucial as it determines the health of future generations. School girls when experiencing menarche find themselves in a setting without water, toilets or a supportive female teacher to explain the changes happening in their body. An important concern for adolescent girls is to have adequate, correct knowledge along with facilities and the cultural environment to manage menstruation hygienically and with dignity. Hence, the present study was done to assess knowledge and practices about menstruation in adolescent school girls of an urban slum...
October 14, 2016: International Journal of Adolescent Medicine and Health
Kenna Degner, Ronald R Magness, Dinesh M Shah
The uterine vasculature undergoes marked changes during pregnancy in order to provide the necessary increase in blood flow to support growth and nutrition of the uterus, placenta, and developing fetus. Pregnancy-associated uterine vascular transformations are orchestrated by a complex array of endocrine and cellular mechanisms to bring about structural modifications at the maternal-fetal interface, which collectively lead to development of the uteroplacental circulation. Understanding intrinsic uterine vascular remodeling in pregnancy is essential for understanding the physiologic and pathophysiologic regulation of maternal uterine blood flow...
October 12, 2016: Reproductive Sciences
Laura G Rico, Jordi Juncà, Mike D Ward, Jolene Bradford, Jordi Petriz
With the aim to detect candidate malignant primitive progenitor populations, we modified an original alkaline phosphatase (ALP) stem cell detection method based on the identification of alkaline phosphatase fluorescent cells in combination with flow cytometry immunophenotyping. Over a period of one year, we have been using this technique to study its activity in patients with leukemia and lymphoma, showing that changes in the alkaline phosphatase levels can be used to detect rare populations of highly refractory malignant cells...
October 6, 2016: Oncotarget
Brittany R Counts, Lindy M Rossow, Kevin T Mattocks, J Grant Mouser, Matthew B Jessee, Samuel L Buckner, Scott J Dankel, Jeremy P Loenneke
Low-load resistance exercise with the blood flow restriction (BFR) has been shown to increase muscle size similar to that of traditional high-load resistance training. Throughout the BFR literature, there is a vast difference between the quantity of young females included in the literature compared to young males, older males and older females. Therefore, the purpose of this minireview is to discuss the underrepresentation of young females in the BFR literature and review the potential physiologic reasons as to why they may have been excluded...
October 11, 2016: Clinical Physiology and Functional Imaging
K T Cumming, S Ellefsen, B R Rønnestad, I Ugelstad, T Raastad
Blood flow restricted exercise (BFRE) with low loads has been demonstrated to induce considerable stress to exercising muscles. Muscle cells have developed a series of defensive systems against exercise-induced stress. However, little is known about acute and long-term effects of BFRE training on these systems. Nine previously untrained females trained low-load BFRE and heavy load strength training (HLS) on separate legs and on separate days to investigate acute and long-term effects on heat shock proteins (HSP) and endogenous antioxidant systems in skeletal muscles...
October 10, 2016: Scandinavian Journal of Medicine & Science in Sports
D A Schmerler, A J Espay
Although currently lacking a sensitive and specific electrophysiologic battery test, functional (psychogenic) dystonia can sometimes be diagnosed with clinically definite certainty using available criteria. Certain regional phenotypes have been recognized as distinctive, such as unilateral lip and jaw deviation, laterocollis with ipsilateral shoulder elevation and contralateral shoulder depression, fixed wrist and finger flexion with relative sparing of the thumb and index fingers, and fixed foot plantar flexion and inversion...
2017: Handbook of Clinical Neurology
Nickolas Kipshidze, Anaka Prakash, Nodar Kipshidze, David Chakhunashvili, Zurab Kakabadze
BACKGROUND: Surgical treatment of obesity is characterized by both early and late complications, and thus, there is a need to develop safe and non-invasive techniques. Ghrelin is an orexigenic hormone produced by the fundus of the stomach, which may represent a novel target for obesity management. Unfortunately, numerous attempts to alter ghrelin levels have failed to present significant clinical results. We describe a novel procedure that involves modifying arterial blood flow to the gastric fundus for limiting plasma ghrelin levels...
October 8, 2016: Obesity Surgery
Felipe D Lisbôa, Tiago Turnes, Rogério S O Cruz, João A G Raimundo, Gustavo S Pereira, Fabrizio Caputo
OBJECTIVES: The present study aimed to determine the effects of ischemic preconditioning on performance in three successive 50-m swimming trials and to measure stroke rate, stroke length and blood lactate accumulation. DESIGN: Counterbalanced, repeated-measures cross-over study. METHODS: On two separate days, eleven competitive male swimmers (20±3 years, 182±5cm, 77±5kg) performed three successive 50-m trials in a 50-m swimming pool, preceded by intermittent bilateral cuff inflation (4× 5-min of blood flow restriction+5-min of cuff deflation) at either 220 for thighs and 180mmHg for arms (ischemic preconditioning) or 20mmHg for both limbs (control-treatment)...
September 20, 2016: Journal of Science and Medicine in Sport
Taylor Wand, Mike Fang, Christina Chen, Nathan Hardy, J Philip McCoy, Bogdan Dumitriu, Neal S Young, Angélique Biancotto
Abnormal telomere lengths have been linked to cancer and other hematologic disorders. Determination of mean telomere content (MTC) is traditionally performed by Southern blotting and densitometry, giving a mean telomere restriction fragment (TRF) value for the total cell population studied. Here, we compared a quantitative Polymerase Chain Reaction approach (qPCR) and a flow cytometric approach, fluorescence in situ hybridization (Flow-FISH), to evaluate telomere content distribution in total patient peripheral blood mononuclear cells or specific cell populations...
October 2016: Cytometry. Part A: the Journal of the International Society for Analytical Cytology
Jason Carson, Raoul Van Loon
In this study the one dimensional blood flow equations are solved using a newly proposed enhanced trapezoidal rule method ETM, which is an extension to the simplified trapezoidal rule method STM. At vessel junctions the conservation of mass and conservation of total pressure are held as system constraints using Lagrange multipliers that can be physically interpreted as external flow rates. The ETM scheme is compared with published arterial network benchmark problems and a dam break problem. Strengths of the ETM scheme include being simple to implement, intuitive connection to lumped parameter models, and no restrictive stability criteria such as the CFL number...
October 6, 2016: International Journal for Numerical Methods in Biomedical Engineering
H W Wu, L Sun, D M Li, H Jing, B Xu, C T Wang, L Zhang
Objective: To summarize the short- and mid-term results on endovascular repair of primary retrograde Stanford type A aortic dissection with an entry tear in distal aortic arch or descending aorta. Methods: Between December 2009 and December 2014, 21 male patients of primary retrograde Stanford type A aortic dissection with a mean age of (52±9) years received endovascular repair in Department of Cardiothoracic Surgery, Jinling Hospital. Among the 21 cases, 17 patients were presented as ascending aortic intramural hematoma, 4 patients as active blood flow in false lumen and partial thrombosis, 8 patients as ulcer on descending aorta combined intramural hematoma in descending aorta, and 13 patients as typical dissection changes...
October 1, 2016: Zhonghua Wai Ke za Zhi [Chinese Journal of Surgery]
Mizuki Sudo, Soichi Ando, Yutaka Kano
INTRODUCTION: We recently developed an animal model to investigate the effects of eccentric contraction (ECC) and blood flow restriction (BFR) on muscle tissue at the cellular level. This study clarified the effects of repeated BFR, ECC, and BFR combined with ECC (BFR+ECC) on muscle fiber hypertrophy. METHODS: Male Wistar rats were assigned to 3 groups: BFR, ECC, and BFR+ECC. The contralateral leg in the BFR group served as a control (CONT). Muscle fiber cross sectional area (CSA) of the tibialis anterior was determined after the respective treatments for 6 weeks...
September 26, 2016: Muscle & Nerve
T Pincez, L Calamy, Z Germont, A Lemoine, A-A Lopes, A Massiot, J Tencer, C Thivent, A Hadchouel
Acute and chronic pulmonary complications are frequent in sickle cell disease (SCD), with different spectrum and characteristics in children and adults. Chronic hypoxia is frequent and plays a role in several respiratory complications in SCD. Furthermore, hypoxia has been associated with a higher risk of cerebral ischemia. Despite differing oxygen affinity between hemoglobin A and S, standard pulse oximetry was shown to be accurate in diagnosing hypoxia in SCD patients. Whereas acute hypoxia management is similar to non-SCD patients, chronic hypoxia treatment is mainly based on a transfusion program rather than long-term oxygen therapy...
October 2016: Archives de Pédiatrie: Organe Officiel de la Sociéte Française de Pédiatrie
Kishio Furuya, Ju Jing Tan, Francis Boudreault, Masahiro Sokabe, Yves Berthiaume, Ryszard Grygorczyk
Extracellular ATP and other nucleotides are important autocrine/paracrine mediators that regulate diverse processes critical for lung function, including mucocilliary clearance, surfactant secretion and local blood flow. Cellular ATP release is mechanosensitive, however, the impact of physical stimuli on ATP release during breathing has never been tested in intact lungs in real-time and remains elusive. In this pilot study, we investigated inflation-induced ATP release in rat lungs ex-vivo by real-time luciferin-luciferase (LL) bioluminescence imaging coupled with simultaneous infrared tissue imaging to identify ATP-releasing sites...
September 16, 2016: American Journal of Physiology. Lung Cellular and Molecular Physiology
Zhen-Kui Wang, Li Xue, Tao Wang, Xiu-Jie Wang, Zhi-Qiang Su
Invariant natural killer T (iNKT) cells are a unique subset of T cells that have been implicated in inflammation, atopy, autoimmunity, infections, and cancer. Although iNKT cells have been extensively studied over the past decade, its role in the pathogenesis of ischemic brain injury is still largely unknown. In our study, we determined whether iNKT cells infiltration occur in a mouse model of permanent cerebral ischemia. C57BL6/J male mice were treated with either alpha-galactosylceramide (α-GalCer) or vehicle control before undergoing permanent middle cerebral artery occlusion (pMCAO)...
October 28, 2016: Neuroscience Letters
Huda Mahmoud, Charlotte Buchanan, Susan T Francis, Nicholas M Selby
PURPOSE OF REVIEW: MRI can noninvasively assess the structure and function of the kidney in a single MRI scan session. This review summarizes recent advancements in functional renal MRI techniques, with a particular focus on clinical applications. RECENT FINDINGS: A number of MRI techniques now provide measures of relevance to the pathophysiology of kidney disease. Diffusion-weighted imaging, used in chronic kidney disease and renal transplantation, shows promise as a measure of renal fibrosis...
November 2016: Current Opinion in Nephrology and Hypertension
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