scholarly journals Zinc(II) Induced Neurological Thrombolytic Activities for COVID-19 Thrombus Prevention, Inflammation, Fibrin Degradation, Fibrinolysis of Dissolving Blood Clots and Blood Flow Reperfusion after Thrombolysis

2021 ◽  
Vol 4 (1) ◽  
Keyword(s):  
Blood Flow ◽  
Blood Clots

scholarly journals A murine photothrombotic stroke model with an increased fibrin content and improved responses to tPA-lytic treatment

2020 ◽  
Vol 4 (7) ◽  
pp. 1222-1231 ◽  
Author(s):  
Yu-Yo Sun ◽  
Yi-Min Kuo ◽  
Hong-Ru Chen ◽  
Jonah C. Short-Miller ◽  
Marchelle R. Smucker ◽  
...  
Keyword(s):  
Blood Flow ◽  
Intravital Imaging ◽  
Tissue Type ◽  
Type Plasminogen Activator ◽  
Blood Clots ◽  
Proximal Middle Cerebral Artery ◽  
Platelet Aggregates ◽  
Photothrombotic Stroke ◽  
The Rose ◽  
Consistent Location

Abstract The Rose Bengal (RB) dye-based photothrombotic stroke (PTS) model has many methodological advantages including consistent location and size of infarct, low mortality, and relatively simple surgical procedures. However, the standard PTS has the caveat of poor responses to tissue-type plasminogen activator (tPA)–mediated lytic treatment, likely as a result of the platelet-rich, fibrin-poor content of the blood clots. Here we tested whether the admixture of thrombin (80 U/kg) and RB dye (50 mg/kg) in the proximal middle cerebral artery (MCA)–targeted PTS will modify the clot composition and elevate the responsiveness to tPA-lytic treatment (Alteplase, 10 mg/kg). Indeed, intravital imaging, immunostaining, and immunoblot analyses showed less-compacted platelet aggregates with a higher fibrin content in the modified thrombin (T) plus RB photothrombotic stroke (T+RB-PTS) model compared with the standard RB-PTS-induced clots. Both RB-PTS and T+RB-PTS showed steady recovery of cerebral blood flow (CBF) in the ischemic border from 1 day after infarction, but without recanalization of the proximal MCA branch. Intravital imaging showed high potency of restoring the blood flow by tPA after single vessel-targeted T+RB-PTS. Further, although intravenous tPA failed to restore CBF or attenuate infarction in RB-PTS, it conferred 25% recovery of CBF and 55% reduction of the infarct size in T+RB-PTS (P < .05) if tPA was administered within 2 hours postphotoactivation. These results suggest that T+RB-PTS produces mixed platelet:fibrin clots closer to the clinical thrombus composition and enhanced the sensitivity to tPA-lytic treatment. As such, the modified photothrombosis may be a useful tool to develop more effective thrombolytic therapies of cerebral ischemia.

scholarly journals Eliminating Vascular Obstruction in Myocardial Infarction by Accelerated Ferromagnetic Microrobot

2021 ◽  
Author(s):  
Abbas Moghanizadeh ◽  
Milad Khanzadi ◽  
Mandana Rajabi
Keyword(s):  
Myocardial Infarction ◽  
Blood Flow ◽  
Artificial Graft ◽  
Blood Clots ◽  
Micro Robot ◽  
Vascular Obstruction ◽  
Short Time ◽  
Unique Potential ◽  
The Magnetic Field

Abstract Background vascular obstruction by clots is one of the main reasons of cardiovascular disease such as myocardial infarction. There is a short time, less than 6 minutes, to establish the blood flow, especially in vital organs. While conventional techniques are not very fast and effective, current micro-robots have inherent limitations such as being slow to achieving this goal. Objective There is a strong requirement to develop microrobots with new principles that can quickly eliminate clot blockage in the vascular. The aim of this study is to evaluate, in-vitro, the efficiency of accelerated ferromagnetic micro-robots in destroying blood clots in an artificial vascular precipitately. Methods An artificial graft with a diameter of 10 mm were used as the vessel. Blood clots with various lengths (5*10 and 10*10 and 20*10mm3 (dimeter*length)) are formed inside the graft. Microrobots made of steel with a length of 1 mm and a width of 0.05 mm are utilized. Besides, an electromagnetic accelerator is prototyped to instantly raise the magnetic field, which accelerates the magnetic micro-robot toward the blocked artery. Blood clots with various lengths (5*10 and 10*10 and 20*10mm3(Dimeter*length)) are formed inside the tube. The effect of voltage from 100 to 400 volts on destroying different lengths of clot has been studied. Results The microrobot enables to destroy the clot and reopen the vessel in a fraction of a second. By increasing the voltage from 100 to 400 volt, the micro-robot is able to destroy clots with longer lengths from 5 to 30 mm. Conclusion results confirm that accelerated microbes have a unique potential in piercing clots to reestablish blood flow.

scholarly journals Open Surgical Thrombectomy and Coronary Stent Placement for Treatment of Aortic Thrombotic Disease in a Bitch

2020 ◽  
Vol 48 ◽  
Author(s):  
Wisley Iemanjá Malaquias Dos Santos ◽  
Ariele Aparecida Ferreira ◽  
Juliane Lais Roman ◽  
Flávio Augusto Vieira Freitag ◽  
Vinicius Gonzalez Peres Albernaz ◽  
...  
Keyword(s):  
Blood Flow ◽  
Medical Treatment ◽  
Clinical Signs ◽  
Coronary Stents ◽  
Abdominal Ultrasonography ◽  
Iliac Arteries ◽  
Thrombotic Disease ◽  
Hind Limbs ◽  
Blood Clots ◽  
Surgical Thrombectomy

Background: The thrombotic aortic disease in dogs and cats is characterized by the pathological formation of blood clots that can rupture and obstruct the blood flow. Abdominal ultrasonography can identify the location and extension of thrombus in the main vasculature and using the doppler it is possible to observe the blood flow around the thrombus. Stents are expandable tube-shaped endoprosthesis characterized as a metal mesh and used to prevent or repair stenoses, allowing liquid, gas, or solids to flow. This report aims to describe the surgical and medical treatment of aortic thrombotic disease followed by coronary stents placement in a bitch.Case: An 8-year-old Shih Tzu bitch, presented for evaluation of a 1-month progressive hind limbs paresis. Nociception was present in both limbs, but the patient presented discomfort and vocalization when manipulating the pelvic limbs. A complete blood count demonstrated anemia, mild neutrophilia, and lymphopenia. Serum biochemistry found an increase in ALT, ALP, blood urea nitrogen, and CK. Abdominal ultrasonography detected mild bulging of the caudal aorta and trifurcation of the iliac arteries. Increased intraluminal echogenicity and absence of blood flow were also detected using duplex doppler. The initial medical treatment was ineffective in improving clinical signs, therefore surgical repair was performed. The aorta was isolated and clamped with Satinsky forceps and incised. The thrombus fragmented during removal. A non-compliant high-pressure balloon was used to dilated and remove small fragments of blood clots from the right and left external iliac arteries. Coronary stents of 32 mm length by 2.75 mm diameter were placed to keep both iliac arteries free. Immediately after the procedure, there was a detectable distal pulse in both hind limbs. Despite intensive medical treatment, the patient evolved to respiratory distress and died on the sixth day after surgery. At necropsy, there were thrombi in the lumen of the arteries and several organs in addition to a large hyaline thrombus occluding 80-90% of the aortic lumen and left femoral artery. In the trifurcation region, clots were present, and stents placed in the iliac arteries were also occluded.Discussion: The occurrence of aortic and iliac thrombosis is associated with several conditions, including neoplasia, chronic kidney disease, heart failure, gastric dilatation-volvulus, hypothyroidism, and hyperadrenocorticism (HAC). In this case, the underlying cause of thromboembolism was supposed to be related to an endocrine condition, since the patient had clinical signs compatible with HAC; however, the low-dose dexamethasone suppression test was borderline and further examination could not be afforded. The diagnosis of thrombosis at the iliac trifurcation was obtained through ultrasonographic examination. Computed tomographic and nuclear resonance imaging could have been applied as well. The medical management of the thromboembolic disease was based on anticoagulant therapy with both heparin and clopidogrel in association with surgical thrombectomy and coronary stents placement. Despite the efforts, the patient died shortly after the surgical procedure, which was expected since high rates of mortality and morbidity is often related to the thromboembolic ischemia. The necroscopic examination of the animal found thrombi at the stents, cranial aorta, and microscopically in several tissues. The failure to directly treat the cause of the thrombus, which could not be diagnosed in time, may negatively interfered in patient survival time. The thrombectomy and coronary stents placement reestablished the femoral pulse immediately after surgery, which has been reported in other studies. The surgical resolution of aortic thrombus should be addressed in further studies.

scholarly journals Rupture of blood clots: Mechanics and pathophysiology

2020 ◽  
Vol 6 (35) ◽  
pp. eabc0496
Author(s):  
Valerie Tutwiler ◽  
Jaspreet Singh ◽  
Rustem I. Litvinov ◽  
John L. Bassani ◽  
Prashant K. Purohit ◽  
...  
Keyword(s):  
Blood Flow ◽  
Protein Unfolding ◽  
Three Dimensional ◽  
Critical Energy ◽  
Human Blood Plasma ◽  
Critical Energy Release Rate ◽  
Material Models ◽  
Fibrin Gels ◽  
Blood Clots ◽  
Life Threatening

Fibrin is the three-dimensional mechanical scaffold of protective blood clots that stop bleeding and pathological thrombi that obstruct blood vessels. Fibrin must be mechanically tough to withstand rupture, after which life-threatening pieces (thrombotic emboli) are carried downstream by blood flow. Despite multiple studies on fibrin viscoelasticity, mechanisms of fibrin rupture remain unknown. Here, we examined mechanically and structurally the strain-driven rupture of human blood plasma–derived fibrin clots where clotting was triggered with tissue factor. Toughness, i.e., resistance to rupture, quantified by the critical energy release rate (a measure of the propensity for clot embolization) of physiologically relevant fibrin gels was determined to be 7.6 ± 0.45 J/m2. Finite element (FE) simulations using fibrin material models that account for forced protein unfolding independently supported this measured toughness and showed that breaking of fibers ahead the crack at a critical stretch is the mechanism of rupture of blood clots, including thrombotic embolization.

Modelling the effect of laminar axially directed blood flow on the dissolution of non-occlusive blood clots

2007 ◽  
Vol 52 (11) ◽  
pp. 2969-2985 ◽  
Author(s):  
I Serša ◽  
J Vidmar ◽  
B Grobelnik ◽  
U Mikac ◽  
G Tratar ◽  
...  
Keyword(s):  
Blood Flow ◽  
Blood Clots

Effect of acoustic exposing on blood flow in microchannel simulating stenosis

2016 ◽  
Vol 11 (2) ◽  
pp. 193-198
Author(s):  
A.T. Akhmetov ◽  
S.P. Sametov ◽  
A.A. Valiev ◽  
A.A. Rakhimov
Keyword(s):  
Blood Flow ◽  
Acoustic Field ◽  
Soft Lithography ◽  
High Speed ◽  
Strong Influence ◽  
Constant Pressure ◽  
Blood Clot ◽  
Ultrasound Field ◽  
Blood Clots ◽  
Flow Features

The work is dedicated to problems connected with blood clot formation and study of blood flow features in vessels with stenosis. Using high-speed recording an analysis of flow structure of biological dispersion (blood) in acoustic field of mild intensity is made. It carried out in microchannel simulating a blood vessel with stenosis made and using soft lithography technology. The flow is arranged at constant pressure drop provided by hydrostatic pump in a range of 100–800 Pa. It was found a strong influence of acoustic field on a dynamics of blood flow in a microchannel at the range of frequencies 20–500 kHz and amplitudes below than 50 kPa. Results show reciprocating movements of flow in a region of microchannel narrowing. It is found a possibility of ultrasound field impact on blood clots formed in region of vessels stenosis.

Effects of Antiplatelet Drugs on Blood Flow through Stenosed Blood Vessels

2013 ◽  
Vol 18 ◽  
pp. 21-27
Author(s):  
Sapna Ratan Shah
Keyword(s):  
Blood Flow ◽  
Fluid Model ◽  
Blood Clot ◽  
Antiplatelet Drugs ◽  
Newtonian Viscosity ◽  
Numerical Illustration ◽  
Blood Flows ◽  
Blood Clots ◽  
Other Substances ◽  
Soft Plaque

Antiplatelet drugs block the formation of blood clots by preventing the clumping of platelets inside arteries, particularly in individuals who have atherosclerosis of their arteries, or are otherwise prone to develop blood clots in their arteries. Atherosclerosis is a slow disease in which arteries become clogged and hardened. Fat, cholesterol, calcium, and other substances form plaque, which builds up in arteries. Hard plaque narrows the passage that blood flows through. That causes arteries to become hard and inflexible. Soft plaque is more likely to break free from the artery wall and cause a blood clot, which can block blood flow to vital organs. In this paper an attempt has been made to investigate the effects of antiplatelet drugs on blood flow and significance of non-Newtonian viscosity through a stenosed artery using Herschel-Bulkely fluid model. Numerical illustration presented at the end of the paper provides the results for the resistance to flow, apparent viscosity and the wall shear stress through their graphical representations.

Innervation of endoneurial microvessels in human sural nerve

1992 ◽  
Vol 50 (1) ◽  
pp. 920-921
Author(s):  
John L. Beggs ◽  
Peter C. Johnson ◽  
Astrid G. Olafsen ◽  
C. Jane Watkins
Keyword(s):  
Blood Flow ◽  
Blood Vessels ◽  
Blood Supply ◽  
Peripheral Nerves ◽  
Sural Nerve ◽  
Nerve Fibers ◽  
Arterial Supply ◽  
Autonomic Nerve ◽  
Vasa Nervorum ◽  
Endoneurial Blood Flow

The blood supply (vasa nervorum) to peripheral nerves is composed of an interconnected dual circulation. The endoneurium of nerve fascicles is maintained by the intrinsic circulation which is composed of microvessels primarily of capillary caliber. Transperineurial arterioles link the intrinsic circulation with the extrinsic arterial supply located in the epineurium. Blood flow in the vasa nervorum is neurogenically influenced (1,2). Although a recent hypothesis proposes that endoneurial blood flow is controlled by the action of autonomic nerve fibers associated with epineurial arterioles (2), our recent studies (3) show that in addition to epineurial arterioles other segments of the vasa nervorum are also innervated. In this study, we examine blood vessels of the endoneurium for possible innervation.

Sign in / Sign up

Export Citation Format

Share Document