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Blood flow occlusion

Tatyana Gavrilchenko, Eleni Katifori
The structure of flow networks determines their function under normal conditions as well as their response to perturbative damage. Brain vasculature often experiences transient or permanent occlusions in the finest vessels, but it is not clear how these microclots affect the large-scale blood flow or to what extent they decrease functionality. Motivated by this, we investigate how flow is rerouted after the occlusion of a single edge in networks with a hierarchy in edge conductances. We find that in two-dimensional networks, vessels formed by highly conductive edges serve as barriers to contain the displacement of flow due to a localized perturbation...
January 2019: Physical Review. E
Munehiro Otsuka, Yuichiro Kikkawa, Tomoya Kamide, Kaima Suzuki, Aoto Shibata, Toshiki Ikeda, Hiroki Kurita
BACKGROUND: This study aimed to investigate factors related to improvement of hemodynamics and evaluated the usefulness of intraoperative Doppler for predicting postoperative hemodynamics in patients with cerebrovascular atherosclerotic steno-occlusive disease (CASD) of the internal carotid artery (ICA) or middle cerebral artery (MCA) who were treated with extracranial-intracranial (EC-IC) bypass surgery. METHOD: Forty-eight patients with CASD of the ICA or MCA who were treated by superficial temporal artery to middle cerebral artery bypass with a follow-up longer than 12 months were enrolled...
February 18, 2019: Acta Neurochirurgica
Arnaud Roussel, Nellie Della Schiava, Raphaël Coscas, Quentin Pellenc, Tarek Boudjelit, Olivier Goëau-Brissonnière, Olivier Corcos, Patrick Lermusiaux, Marc Coggia, Yves Castier
OBJECTIVE: Acute mesenteric ischemia (AMI) is an emergent event with a high mortality rate; survivors have high rates of intestinal failure. Restoration of blood flow using endovascular or surgical revascularization is associated with better outcome in terms of survival rate and intestinal resection. Retrograde open mesenteric stenting (ROMS), which is a hybrid technique, combines two benefits: prompt blood flow restoration with an endovascular approach and inspection and resection of the small bowel...
February 15, 2019: Journal of Vascular Surgery
Francesco Acerbi, Francesco Prada, Ignazio G Vetrano, Jacopo Falco, Giuseppe Faragò, Paolo Ferroli, Francesco DiMeco
BACKGROUND: Distal outflow occlusion and extracranial-intracranial bypass represent a possible option for the surgical management of complex middle cerebral artery (MCA) aneurysm. A limitation of distal clipping strategy combined to bypass relies on the difficulties in predicting intraoperatively the good blood flow supply to the brain territory distal to the aneurysm and the extent and speed of aneurysmal thrombosis. METHODS: The authors presented an innovative approach in which Contrast-enhanced US (CEUS) and indocyanine green video-angiography (ICG-VA) have been synergistically used to study the effect of distal clipping on the aneurysm flow and the parenchymal blood flow after the bypass...
February 15, 2019: World Neurosurgery
Mustafa Gok, Hilal Altas, Hasan Burhanettin Kapti
OBJECTIVE: To evaluate the effect of single intravitreal Dexamethasone implant (Ozurdex®) on ocular blood flow velocities in patients with diabetic macular edema (DME) and retinal vein occlusions (RVO). METHODS: This prospective non-randomized interventional study included injected and fellow eyes of 12 patients with diabetic macular edema (DME) and of 16 patients with retinal vein occlusion (RVO) treated with intravitreal Ozurdex®. Color Doppler Ultrasonography (CDU) measures of the central retinal artery (CRA), posterior ciliary artery (PCA), ophthalmic artery (OA) those are peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI) and pulsatility index (PI) were performed in both injected and uninjected eyes before injection, at one week, one month after injection, and prior to re-injection...
February 17, 2019: Cutaneous and Ocular Toxicology
Yu Shimizu, Katsuhiro Tsuchiya, Hironori Fujisawa
BACKGROUND: Cerebral venous thrombosis is rare and an uncommon cause of stroke and has diverse etiologies and varied clinical presentations. Here, we report 2 cases of deep cerebral venous thrombosis. CASE DESCRIPTION: A 64-year-old woman presented with cerebral venous thrombosis due to a hypercoagulable state associated with ovarian tumor. On initial fluid-attenuated inversion recovery and diffusion-weighted imaging, there was a diffuse high-intensity lesion in the bilateral thalamus...
February 13, 2019: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
Sophie Masmejan, David Baud, Greg Ryan, Tim Van Mieghem
In this review article, we discuss the most common fetal tumors, their prenatal management, and outcomes. Overall, the most important outcome predictors are tumor histology, size, vascularity, and location. Very large lesions, lesions causing cardiac failure, and hydrops and lesions obstructing the fetal airway have the poorest outcome, as they may cause fetal death or complications at the time of delivery. Fetal therapy has been developed to improve outcomes for the most severe cases and can consist of transplacental therapy (sirolimus for rhabdomyomas or steroids for hemangiomas and microcystic lung lesions) or surgical intervention (shunting of cystic masses, tumor ablation, occlusion of blood flow or airway exploration, and protection)...
January 14, 2019: Best Practice & Research. Clinical Obstetrics & Gynaecology
Masahiro Horiuchi, Junko Endo, Takashi Sato, Koichi Okita
This study investigated whether jump training with blood flow restriction (BFR) improves jump performance compared to jump training without BFR under similar exercise intensity in healthy young humans. The participants were twenty healthy males who were assigned to either jump training with BFR (n = 10) or jump training without BFR [control (CON); n = 10] groups. All subjects completed five sets of 10 repetitions with one-minute intervals of half-squat jumps (SJ) at maximal effort, four days a week for four weeks...
December 2018: Biology of Sport
Alyssa M Weatherholt, William R Vanwye, Jackie Lohmann, Johnny G Owens
The purpose of this study was to compare the standing lower extremity limb occlusion pressure (LOP) between two units. It was hypothesized that the Delfi unit, which utilizes a wider cuff (11.5 cm), would require significantly less LOP as compared to the KAASTU unit, which utilizes a narrow cuff (5 cm). Twenty-nine healthy participants (22 men, 7 women) mean age 24 years old (± 1.7 SD) volunteered. The procedure was identical for each cuff, completed with 5 minutes of rest in between. The cuff was placed on the proximal left thigh in the standing position...
2019: International Journal of Exercise Science
Takeo Matsusue
BACKGROUND: Antithrombotic therapy following replantation remains controversial, and the survival of replanted digits is affected by various other factors, such as the state of vascular damage and the surgeon's level of skill. The present study's aim is to obtain clinical evidence for postoperative antithrombotic therapy in replantation, with antithrombotic therapy being the only variable. METHODS: This was a single-center retrospective study of patients who underwent replantation of a completely amputated digit by the same surgeon...
March 2019: Journal of Hand Surgery Asian-Pacific Volume
Xianjun Huang, Mei Wan, Qian Yang, Xianhui Ding, Zhiming Zhou
OBJECTIVE: The stromal cell-derived factor-1α/cysteine-X-cysteine chemokine receptor 4 (SDF-1α/CXCR4) axis promotes neuroprotection and angiogenesis in animal studies. Few studies have investigated the potential clinical implications of the SDF-1α/CXCR4 axis in patients with acute ischemic stroke (AIS). We evaluated the prognostic values of the SDF-1α/CXCR4 axis in patients with proximal middle cerebral artery occlusion. METHODS: Fifty-five patients and 18 age- and sex-matched volunteers were enrolled...
February 14, 2019: Journal of International Medical Research
I F Ricarte, L A Dutra, O G P Barsottini, A W S de Souza, D C O de Andrade, Clp Mangueira, G S Silva
INTRODUCTION: Transcranial Doppler is a method that enables the assessment of different cerebral hemodynamic parameters. It also allows for the evaluation of the presence of right-to-left circulation shunts (RLS) and for the detection of microembolic signals (MESs), which might be associated with an increased risk of cerebrovascular events. For instance, the presence of MESs on transcranial Doppler in patients with systemic lupus erythematous (SLE) and antiphospholipid syndrome (APS) is associated with an increased risk of stroke...
February 12, 2019: Lupus
Christiaan Hendrik Bas van Niftrik, Martina Sebök, Giovanni Muscas, Marco Piccirelli, Carlo Serra, Niklaus Krayenbühl, Athina Pangalu, Oliver Bozinov, Andreas Luft, Christoph Stippich, Luca Regli, Jorn Fierstra
The clinical significance of ipsilateral thalamic diaschisis (ITD) occurring after stroke is unknown. To characterize ITD, we investigate its hemodynamic, structural, and clinical implications. A single-institution prospective cross-sectional study was conducted using 28 symptomatic cerebrovascular steno-occlusive patients undergoing both BOLD-CVR and Diamox-challenged 15 (O)-H2 O-PET. Follow-up was at least three months. In addition, 15 age-matched healthy subjects were included. ITD was diagnosed based on a BOLD-CVR thalamic asymmetry index (TAI) > +2 standard deviations from healthy subjects...
February 12, 2019: Journal of Cerebral Blood Flow and Metabolism
Peng Hu, Hong-Qi Zhang, Xiao-Yu Li, Xian-Zeng Tong
BACKGROUND: The STA connected to proximal MCA has been reported before. However, the flow supply capacity of the double-barrel STA to proximal MCA bypass in treating complex intracranial aneurysms has not been well documented. METHODS: Consecutive cases using this technique to treat complex intracranial aneurysms during the past five years have been collected. SEP and MEP monitoring were applied for each patient to determine any ischaemic events during the surgery...
February 8, 2019: World Neurosurgery
George W Farr, Christopher H Hall, Susan M Farr, Ramon Wade, Joshua M Detzel, Amielia G Adams, Jasen M Buch, Derek L Beahm, Christopher A Flask, Kui Xu, Joseph C LaManna, Paul R McGuirk, Walter F Boron, Marc F Pelletier
Cerebral edema in ischemic stroke can lead to increased intracranial pressure, reduced cerebral blood flow and neuronal death. Unfortunately, current therapies for cerebral edema are either ineffective or highly invasive. During the development of cytotoxic and subsequent ionic cerebral edema water enters the brain by moving across an intact blood brain barrier and through aquaporin-4 (AQP4) at astrocyte endfeet. Using AQP4-expressing cells, we screened small molecule libraries for inhibitors that reduce AQP4-mediated water permeability...
February 6, 2019: Neuroscience
Írisz Szabó, Orsolya M Tóth, Zsolt Török, Dániel Péter Varga, Ákos Menyhárt, Rita Frank, Dóra Hantosi, Ákos Hunya, Ferenc Bari, Ibolya Horváth, László Vigh, Eszter Farkas
BACKGROUND AND PURPOSE: A new class of heat shock protein co-inducer dihydropyridine derivatives devoid of calcium channel antagonist and vasodilator effects have been recently developed with the purpose to target neurodegeneration selectively. Here we set out to evaluate the action of one of these novel compounds LA1011 on neurovascular coupling in the ischemic rat cerebral cortex. As a reference, we applied nimodipine, a well-known calcium channel antagonist, vasodilator dihydropyridine compound...
February 9, 2019: British Journal of Pharmacology
Yong I Jeong, Gregory A Christoforidis, Niloufar Saadat, Keigo Kawaji, Charles G Cantrell, Steven Roth, Marek Niekrasz, Timothy J Carroll
PURPOSE: This work sought to compare a quantitative T1 bookend dynamic susceptibility contrast MRI based perfusion protocol for absolute cerebral blood flow (qCBF) against CBF measured by the stable-isotope neutron capture microsphere method, a recognized reference standard for measuring tissue blood flow, at normocapnia, hypercapnia, and in acute stroke. METHODS: CBF was measured in anesthetized female canines by MRI and microspheres over 2 consecutive days for each case...
February 8, 2019: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Tim Kaufeld, Eric Beckmann, Fabio Ius, Nurbol Koigeldiev, Wiebke Sommer, Bakr Mashaqi, Felix N Fleissner, Thierry Siemeni, Jacob Ono Puntigam, Jessica Kaufeld, Axel Haverich, Christian Kuehn
BACKGROUND: Venoarterial extracorporeal membrane oxygenation support is a well-established tool in the care of severe refractory cardiac and respiratory failure. The application of this support may serve as a bridge to transplant, recovery or to implantation of a ventricular assist device. Venoarterial extracorporeal membrane oxygenation support can be administered through an open surgical access via the common femoral or axillary artery or a percutaneous approach using Seldinger technique...
February 8, 2019: Perfusion
David B Copithorne, Charles L Rice
PURPOSE: Blood flow restriction (BFR) with low-intensity (< 30% of 1 repetition maximum strength) muscle contraction has been used chronically (> 4 weeks) to enhance resistance training. However, mechanisms underlying muscle adaptations following BFR are not well understood. To explore changes related to chronic BFR adaptations, the current study used blood flow occlusion (BFO) during an acute bout of low-intensity isometric fatiguing contractions to assess peripheral (muscle) factors affected...
February 8, 2019: European Journal of Applied Physiology
Xinren Yu, Scott L Diamond
Neutrophils can release extracellular traps (NETs) in infectious, inflammatory and thrombotic diseases. NETs have been detected in deep vein thrombosis, atherothrombosis, stroke, disseminated intravascular coagulation and trauma. We have previously shown that haemodynamic forces trigger rapid NETosis within sterile occlusive thrombi in vitro. Here, we tested the effects of thrombin, fibrin and fibrinolysis on shear-induced NETosis by imaging NETs with Sytox Green during microfluidic perfusion of factor XIIa-inhibited or thrombin-inhibited human whole blood over fibrillar collagen (±tissue factor)...
February 5, 2019: Thrombosis and Haemostasis
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