Thrombolysis by Ultrasound

1976 ◽  
Vol 51 (s3) ◽  
pp. 697s-698s ◽  
Author(s):  
G. Trübestein ◽  
C. Engel ◽  
F. Etzel ◽  
A. Sobbe ◽  
H. Cremer ◽  
...  
Keyword(s):  
Side Effects ◽  
Vessel Wall ◽  
Ultrasonic Transducer ◽  
Vacuum Pump ◽  
Microscopic Structure ◽  
Ultrasonic Frequency ◽  
Hollow Waveguide ◽  
Plastic Tube ◽  
Frequency Counter ◽  
Arteries And Veins

1. A new method of destroying thrombi in blood vessels by ultrasound and simultaneously removing them is reported. 2. Experiments were performed in twenty dogs with artificial thrombi in the iliac and femoral arteries and veins. The length of the thrombi ranged from 4 to 5 cm and the age from 12 h to 10 days. The unit used consisted of a generator, a frequency counter, an ultrasonic transducer with the hollow waveguide and a vacuum pump. For protection of the vessel wall the guide is surrounded by a plastic tube. The ultrasonic frequency is 26·5 kHz, the amplitude 25–30 μm. The time needed to destroy the thrombus by ultrasound and suck out the thrombotic material ranged from 2·5 to 5 min. 3. To check side effects, experiments were performed in forty-four dogs. No significant changes were seen in the fibrinolytic system or microscopic structure of the vessel wall after ultrasound.

scholarly journals The effect of vascular diseases on bioimpedance measurements: mathematical modeling

2018 ◽  
Vol 5 (6) ◽  
Author(s):  
Yomna H. Shash ◽  
Mohamed A. A. Eldosoky ◽  
Mohamed T. Elwakad
Keyword(s):  
Mathematical Models ◽  
Vessel Wall ◽  
Vascular Diseases ◽  
Impedance Analysis ◽  
Wide Field ◽  
Vascular Disorders ◽  
Non Invasive ◽  
Novel Method ◽  
Inner Vessel ◽  
Arteries And Veins

Introduction: The non-invasive nature of bioimpedance technique is the reason for the adoption of this technique in the wide field of bio-research. This technique is useful in the analysis of a variety of diseases and has many advantages. Cardiovascular diseases are the most dangerous diseases leading to death in many regions of the world. Vascular diseases are disorders that affect the arteries and veins. Most often, vascular diseases have greater impacts on the blood flow, either by narrowing or blocking the vessel lumen or by weakening the vessel wall. The most common vascular diseases are atherosclerosis, wall swelling (aneurysm), and occlusion. Atherosclerosis is a disease caused by the deposition of plaques on the inner vessel wall, while a mural aneurysm is formed as a result of wall weakness. The main objective of this study was to investigate the effects of vascular diseases on vessel impedance. Furthermore, this study aimed to develop the measurement of vessel abnormalities as a novel method based on the bioimpedance phenomenon. Methods: Mathematical models were presented to describe the impedance of vessels in different vascular cases. In addition, a 3D model of blood vessels was simulated by COMSOL MULTIPHYSICS.5, and the impedance was measured at each vascular condition. Results: The simulation results clarify that the vascular disorders (stenosis, blockage or aneurysm) have significant impact on the vessel impedance, and thus they can be detected by using the bio-impedance analysis. Moreover, using frequencies in KHz range is preferred in detecting vascular diseases since it has the ability to differentiate between the healthy and diseased blood vessel. Finally, the results can be improved by selecting an appropriate electrodes configuration for analysis. Conclusion: From this work, it can be concluded that bioimpedance analysis (BIA) has the ability to detect vascular diseases. Furthermore, the proposed mathematical models are successful at describing different cases of vascular disorders.

Δ4-Ethyloestrenol in Recurrent Deep Venous Thrombosis

1981 ◽  
Vol 26 (1_suppl) ◽  
pp. S91-S92
Author(s):  
B. Nilsson ◽  
I. M. Nilsson ◽  
U. Hedner
Keyword(s):  
Side Effects ◽  
Venous Thrombosis ◽  
Deep Venous Thrombosis ◽  
Plasminogen Activator ◽  
Anabolic Steroid ◽  
Vessel Wall ◽  
Vascular Occlusion ◽  
Fibrinolytic Parameters

Twenty-one patients with recurrent deep venous thrombosis were treated with an anabolic steroid (Δ4-ethyloestrenol) for up to 56 months. All had been shown to have a deficient fibrinolytic response to vascular occlusion and/or low vessel wall plasminogen activator content. Therapy resulted in improvement in clinical and fibrinolytic parameters and no significant side effects were seen.

Side-Effects of Rinsing Fluids on the Rat Femoral Artery

1997 ◽  
Vol 22 (5) ◽  
pp. 568-573 ◽  
Author(s):  
O. DELAERE ◽  
U. MENNEN ◽  
W. VAN HEERDEN ◽  
E. RAUBENHEIMER ◽  
A. M. WIESE ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Side Effects ◽  
Femoral Artery ◽  
Normal Saline ◽  
Vessel Wall ◽  
Experimental Conditions ◽  
Femoral Arteries ◽  
Heparinized Saline ◽  
Significant Difference ◽  
Ringer’S Lactate

Rinsing rat femoral arteries with various fluids in experimental conditions similar to those in clinical practice was found to have deleterious effects on the intimal and medial layers of the vessels. No statistically significant difference was found between the effects of Ringer’s lactate and normal saline. Heparinized saline produced significantly less damage to the medial layer and less platelet cell deposition. Lignocaine 2% was found to be extremely damaging to the whole vessel wall, and highly thrombogenic. Nevertheless, all the arteries in each group remained patent 4 days after rinsing.

Oxidative stress and endothelial dysfunction

2007 ◽  
Vol 27 (01) ◽  
pp. 5-12 ◽  
Author(s):  
G. Muller ◽  
C. Goettsch ◽  
H. Morawietz
Keyword(s):  
Oxidative Stress ◽  
Endothelial Dysfunction ◽  
Vascular Function ◽  
Vessel Wall ◽  
Clinical Implications ◽  
Oxygen Species ◽  
Vascular Oxidative Stress ◽  
Arteries And Veins ◽  
Different Sources

SummaryThis review focuses on the role of vascular oxidative stress in the development and progression of endothelial dysfunction. We discuss different sources of oxidative stress in the vessel wall, oxidative stress and coagulation, the role of oxidative stress and vascular function in arteries and veins, the flow-dependent regulation of reactive oxygen species, the putative impact of oxidative stress on atherosclerosis, the interaction of angiotensin II, oxidative stress and endothelial dysfunction, and clinical implications.

Effect of Ethyloestrenol on Fibrinolysis in the Vessel Wall

1975 ◽  
Author(s):  
U. Hedner ◽  
I. M. Nilsson ◽  
S. Isacson
Keyword(s):  
Side Effects ◽  
Venous Thrombosis ◽  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Vessel Wall ◽  
Marked Decrease ◽  
Venous Occlusion

It has been shown that phenformin plus ethyloestrenol causes a significant increase in the fibrinolytic activity of the vessel wall in most patients with recurrent idiopathic venous thrombosis and with an initially low fibrinolytic activity in the vein walls. At the same time a marked decrease in the frequency of thrombotic episodes occurred (Nilsson et al. 1974). Due to side effects of phenformin attempts have been made to administrate ethyloestrenol alone to patients with an abnormally low plasminogen activator content of the vessel wall and/or a decreased capacity to release plasminogen activator from the vein walls on venous occlusion of the arms. Ethyloestrenol in a dose of 8 mg/d has been given to 34 patients for 3 to 6 months and to 6 patients for 12 months. Ethyloestrenol caused a significant increase in the fibrinolytic activity in 30 of the 34 patients treated for 3-6 months and in 5 of those 6 treated for 12 months. Ethyloestrenol in a dose of 4 mg/d had no effect.

scholarly journals Analysis of Applying Ultrasonic Frequency on a Desktop FDM Nozzle

2015 ◽  
Vol 761 ◽  
pp. 329-332 ◽  
Author(s):  
S. Maidin ◽  
Khairul Fahmi Abdul Aziz ◽  
M.K. Muhamad ◽  
E. Pei
Keyword(s):  
Surface Finish ◽  
Computer Aided Design ◽  
Fused Deposition Modeling ◽  
Ultrasonic Transducer ◽  
Ultrasonic Frequency ◽  
Machining Processes ◽  
Fused Deposition ◽  
Good Surface ◽  
Computer Aided ◽  
Good Surface Finish

Fused deposition modeling (FDM) is an additive manufacturing (AM) process that has an economical advantage compared to other AM processes. However, its biggest drawback is that it requires post processing to achieve a good surface finish. Ultrasound has been applied in various conventional machining processes and produces a good surface finish. However, the application of ultrasound to AM has not been sufficiently explored. This research aims to investigate the application of using ultrasound technology for a desktop FDM system. The idea is to transmit high vibration from the ultrasonic transducer to the FDM system's nozzle, and the objective is to examine whether the nozzle is able to withstand the high vibration being transmitted. Computer-aided design (CAD) software used to develop the 3D model of the extrusion nozzle component and a computer-aided engineering (CAE) software was used to perform static and vibration analysis. A frequency range of 20 to 30kHz and 30 to 40kHz was applied to the nozzle and it was found that the nozzle was able to withstand frequencies up to 40 kHz of vibration. In addition, the lowest Factor of Safety (FoS) obtained was 18.8975, concluding that the nozzle of FDM can withstand the high vibration transmitted from the ultrasonic transducer.

Effects of myocardial constraint on the passive mechanical behaviors of the coronary vessel wall

2008 ◽  
Vol 294 (1) ◽  
pp. H514-H523 ◽  
Author(s):  
Yi Liu ◽  
Wei Zhang ◽  
Ghassan S. Kassab
Keyword(s):  
Vessel Wall ◽  
Coronary Vessels ◽  
Pressure Overload ◽  
Wall Stress ◽  
Surrounding Tissue ◽  
Stress And Strain ◽  
Structural Adaptation ◽  
Mechanical Basis ◽  
Different Depths ◽  
Arteries And Veins

The large epicardial coronary arteries and veins span the surface of the heart and gradually penetrate into the myocardium. It has recently been shown that remodeling of the epicardial veins in response to pressure overload strongly depends on the degree of myocardial support. The nontethered regions of the vessel wall show significant intimal hyperplasia compared with the tethered regions. Our hypothesis is that such circumferentially nonuniform structural adaptation in the vessel wall is due to nonuniform wall stress and strain. Transmural stress and strain are significantly influenced by the support of the surrounding myocardial tissue, which significantly limits distension of the vessel. In this finite-element study, we modeled the nonuniform support by embedding the left anterior descending artery into the myocardium to different depths and analyzed deformation and strain in the vessel wall. Circumferential wall strain was much higher in the untethered than tethered region at physiological pressure. On the basis of the hypothesis that elevated wall strain is the stimulus for remodeling, the simulation results suggest that large epicardial coronary vessels have a greater tendency to become thicker in the absence of myocardial constraint. This study provides a mechanical basis for understanding the local growth and remodeling of vessels subjected to various degrees of surrounding tissue.

scholarly journals The Effect of Ultrasonic Frequency on Gold Wire Bondability and Reliability

2009 ◽  
Vol 6 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Jianbiao Pan ◽  
Minh-Nhat Le ◽  
Cuong Van Pham
Keyword(s):  
Ultrasonic Transducer ◽  
Gold Wire ◽  
Temperature Cycling ◽  
Experimental Methodology ◽  
Test Time ◽  
Time Interval ◽  
Ultrasonic Frequency ◽  
Ultrasonic Power ◽  
Bonding Parameters ◽  
Wire Bonds

This paper presents a systematic study on the effect of 120 KHz ultrasonic frequency on the bondability and reliability of fine pitch gold wire bonding to pads over an organic substrate with gold metallizations. The study was carried out on a thermosonic ball bonder that is allowed to easily switch between ultrasonic frequencies of 60 KHz and 120 KHz by changing the ultrasonic transducer and the ultrasonic generator. Bonding parameters were optimized through the design of experimental methodology for four different cases: 25.4 μm wire at 60 kHz, 25.4 μm wire at 120 kHz, 17.8 μm wire at 60 kHz, and 17.8 μm wire at 120 kHz. The integrity of wire bonds was evaluated by six response variables. The optimized bonding process was selected according to the multiattribute utility theory. With the optimized bonding parameters developed on one metallization for each of the four cases, 8,100 bonds were made on five different metallizations. The samples were then divided into three groups. The first group was subjected to humidity at 85°C/85% RH for up to 1,000 h. The second group was subjected to thermal aging at 125°C for up to 1,000 h. The third group was subjected to temperature cycling from −55°C to +125°C with 1 h per cycle for up to 1,000 cycles. The bond integrity was evaluated through the wire pull and the ball shear tests immediately after bonding, and after each 150, 300, 500, and 1,000 h time interval in the reliability tests. Results show that 120 kHz frequency requires less ultrasonic power than 60 kHz when all other parameters are equal. The results also indicate that bonding at 120 kHz frequency is less sensitive to different metallizations than bonding at 60 kHz. All three reliability tests do not negatively affect the bond integrity of Au wire bonds on a variety of Au metallizations for both frequencies. Furthermore, as the reliability test time increases, both pull and shear strengths of Au wire bonds on Au pads increase.

Fibrinolysis in Grafted Arteries and Veins

1978 ◽  
Vol 40 (02) ◽  
pp. 512-517 ◽  
Author(s):  
Bo Risberg
Keyword(s):  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Vessel Wall ◽  
Observation Time ◽  
Caval Vein ◽  
Vein Grafts ◽  
Aortic Segment ◽  
Plasminogen Activator Activity ◽  
Arteries And Veins

SummaryThe fibrinolytic activity in autologous artery and vein grafts was studied in cats during a 4-month period. The fibrinolytic activity in the wall of an aortic segment interposed in the caval vein was increased in comparison to the normal aorta. In the corresponding segment of the caval vein interposed in the aorta, the fibrinolytic activity was reduced during the observation time. Thrombosed segments had a decreased activity. No changes were seen in sham operated animals. The plasminogen activator activity in the vessel wall was found to be influenced by the surrounding milieu.

Sign in / Sign up

Export Citation Format

Share Document