616 In Vitro Test of Behavior of Jyros Artificial Heart Valve

2006 ◽  
Vol 2006.81 (0) ◽  
pp. _6-19_
Author(s):  
Tomohiro SHIROYAMA
Keyword(s):  
Heart Valve ◽  
Artificial Heart ◽  
Artificial Heart Valve ◽  
In Vitro Test ◽  
Vitro Test

Fluid-structure interaction simulation of artificial textile reinforced aortic heart valve: Validation with an in-vitro test

2018 ◽  
Vol 78 ◽  
pp. 52-69 ◽  
Author(s):  
Deepanshu Sodhani ◽  
Stefanie Reese ◽  
Andrey Aksenov ◽  
Sinan Soğanci ◽  
Stefan Jockenhövel ◽  
...  
Keyword(s):  
Heart Valve ◽  
Fluid Structure Interaction ◽  
In Vitro Test ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aortic Heart Valve ◽  
Vitro Test ◽  
Interaction Simulation

scholarly journals Pressure sensor emulator to improve longterm stability of heart valve testing systems

2019 ◽  
Vol 5 (1) ◽  
pp. 493-495
Author(s):  
Wolfram Schmidt ◽  
Carsten Tautorat ◽  
Niels Grabow ◽  
Sebastian Kaule ◽  
Jörg Kaminsky ◽  
...  
Keyword(s):  
Heart Valve ◽  
Artificial Heart ◽  
Dynamic Properties ◽  
Pressure Sensors ◽  
Artificial Heart Valve ◽  
Test Procedures ◽  
Heart Valve Prostheses ◽  
System Verification ◽  
Valve Prostheses

AbstractFluid mechanical characterization of artificial heart valve prostheses requires reliable measurement of temperature, flow and pressure at normal heart rate. In vitro fatigue test procedures of artificial heart valve prostheses can take several months with up to 400 million cycles to assess valve performance and durability under simulated cardiac conditions at increased pulse frequency. In both cases, a minimum of user interventions for recalibration are required. In these tests, pressure data are collected for hydrodynamic heart valve characterization and for closed-loop control of pressure loading. In our study, the improvement of commercial heart valve testing systems (Vivitro Pulse Duplicator, Vivitro Labs Inc. and VDT-3600i, BDC Laboratories) is considered by substituting the built-in disposable pressure sensors (lifetime: one week) by longterm stable sensors. The selected highly accurate sensors (86A, TE Connectivity Corp.) provide amplified, linearized, calibrated and temperature compensated analog output signals. Their stainless steel construction allows for high media compatibility with corrosive liquids. Due to different sensitivity characteristics, these sensors are not fully compatible to the testing devices. To overcome this limitation, application-specific emulator interfaces were developed to connect the new sensors to the data acquisition part of the validated valve testing systems. To stay consistent with manufacturer’s device and software specification, we utilized fast analog signal conditioning, including scaling, offset calibration, out of range alarm and status indication. Compared to the originally equipped pressure sensors, emulator parameters, such as pressure range, precision, resolution and accuracy remained unchanged or even improved. For system verification the response characteristic, long-term stability and dynamic properties were examined in comparative studies

Development and Evaluation of a Novel Artificial Catheter-Deliverable Prosthetic Heart Valve and Method for in Vitro Testing

2009 ◽  
Vol 32 (5) ◽  
pp. 262-271 ◽  
Author(s):  
Thomase Claiborne ◽  
Danny Bluestein ◽  
Richard T. Schoephoerster
Keyword(s):  
Heart Valve ◽  
State Of The Art ◽  
Prosthetic Heart Valve ◽  
Test Methods ◽  
In Vitro Testing ◽  
In Vitro Test ◽  
Vitro Test ◽  
Percutaneous Heart Valve

Background This work presents a novel artificial prosthetic heart valve designed to be catheter or percutaneously deliverable, and a method for in vitro testing of the device. The device is intended to create superior characteristics in comparison to tissue-based percutaneous valves. Methods The percutaneous heart valve (PHV) was constructed from state-of-the-art polymers, metals and fabrics. It was tested hydrodynamically using a modified left heart simulator (LHS) and statically using a tensile testing device. Results The PHV exhibited a mean transvalvular pressure gradient of less than 15 mmHg and a mean regurgitant fraction of less than 5 percent. It also demonstrated a resistance to migration of up to 6 N and a resistance to crushing of up to 25 N at a diameter of 19 mm. The PHV was crimpable to less than 24 F and was delivered into the operating LHS via a 24 F catheter. Conclusion An artificial PHV was designed and optimized, and an in vitro methodology was developed for testing the valve. The artificial PHV compared favorably to existing tissue-based PHVs. The in vitro test methods proved to be reliable and reproducible. The PHV design proved the feasibility of an artificial alternative to tissue based PHVs, which in their traditional open-heart implantable form are known to have limited in vivo durability.

IN VITRO 3D HIGH SPEED PIV MEASUREMENTS BEHIND AN AORTIC ARTIFICIAL HEART VALVE

ASAIO Journal ◽  
2006 ◽  
Vol 52 (2) ◽  
pp. 4A ◽  
Author(s):  
Radoslav Kaminsky ◽  
Stephan Kallweit ◽  
Hans J. Weber ◽  
Antoine P. Simons ◽  
Pascal Verdonck
Keyword(s):  
Heart Valve ◽  
High Speed ◽  
Artificial Heart ◽  
Artificial Heart Valve ◽  
Piv Measurements

Haemostatic Platelet Plug Formation in the Isolated Rabbit Mesenteric Preparation - An Analysis of Red Blood Cell Participation

1980 ◽  
Vol 44 (01) ◽  
pp. 006-008 ◽  
Author(s):  
D Bergqvist ◽  
K-E Arfors
Keyword(s):  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
In Vitro Test ◽  
Pharmacological Agents ◽  
Vitro Test ◽  
Releasing Effect ◽  
Plug Formation

SummaryIn a model using an isolated rabbit mesenteric preparation microvessels were transected and the time until haemostatic plugs formed was registered. Perfusion of platelet rich plasma gave no haemostasis whereas whole blood did. Addition of chlorpromazine or adenosine to the whole blood significantly prolonged the time for haemostasis, and addition of ADP to the platelet rich plasma significantly shortened it. It is concluded that red cells are necessary for a normal haemostasis in this model, probably by a combination of a haemodynamic and ADP releasing effect.The fundamental role of platelets in haemostatic plug formation is unquestionable but there are still problems concerning the stimulus for this process to start. Three platelet aggregating substances have been discussed – thrombin, adenosine diphosphate (ADP) and collagen. Evidence speaking in favour of thrombin is, however, very minimal, and the discussion has to be focused on collagen and ADP. In an in vitro system using polyethylene tubings we have shown that "haemostasis" can be obtained without the presence of collagen but against these results can be argued that it is only another in vitro test for platelet aggregation (1).To be able to induce haemostasis in this model, however, the presence of red blood cells is necessary. To further study this problem we have developed a model where haemostatic plug formation can be studied in the isolated rabbit mesentery and we have briefly reported on this (2).Thus, it is possible to perfuse the vessels with whole blood as well as with platelet rich plasma (PRP) and different pharmacological agents of importance.

scholarly journals In Vitro Newly Isolated Environmental Phage Activity against Biofilms Preformed by Pseudomonas aeruginosa from Patients with Cystic Fibrosis

2021 ◽  
Vol 9 (3) ◽  
pp. 478
Author(s):  
Ersilia Vita Fiscarelli ◽  
Martina Rossitto ◽  
Paola Rosati ◽  
Nour Essa ◽  
Valentina Crocetta ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Multidrug Resistant ◽  
In Vitro Test ◽  
Chronic Infections ◽  
Hospital Environments ◽  
Vitro Test ◽  
General Reliability ◽  
Phage Activity

As disease worsens in patients with cystic fibrosis (CF), Pseudomonas aeruginosa (PA) colonizes the lungs, causing pulmonary failure and mortality. Progressively, PA forms typical biofilms, and antibiotic treatments determine multidrug-resistant (MDR) PA strains. To advance new therapies against MDR PA, research has reappraised bacteriophages (phages), viruses naturally infecting bacteria. Because few in vitro studies have tested phages on CF PA biofilms, general reliability remains unclear. This study aimed to test in vitro newly isolated environmental phage activity against PA isolates from patients with CF at Bambino Gesù Children’s Hospital (OBG), Rome, Italy. After testing in vitro phage activities, we combined phages with amikacin, meropenem, and tobramycin against CF PA pre-formed biofilms. We also investigated new emerging morphotypes and bacterial regrowth. We obtained 22 newly isolated phages from various environments, including OBG. In about 94% of 32 CF PA isolates tested, these phages showed in vitro PA lysis. Despite poor efficacy against chronic CF PA, five selected-lytic-phages (Φ4_ZP1, Φ9_ZP2, Φ14_OBG, Φ17_OBG, and Φ19_OBG) showed wide host activity. The Φ4_ZP1-meropenem and Φ14_OBG-tobramycin combinations significantly reduced CF PA biofilms (p < 0.001). To advance potential combined phage-antibiotic therapy, we envisage further in vitro test combinations with newly isolated phages, including those from hospital environments, against CF PA biofilms from early and chronic infections.

In Vitro Toxicology Methods in Risk Assessment

1996 ◽  
Vol 24 (3) ◽  
pp. 325-331
Author(s):  
Iain F. H. Purchase
Keyword(s):  
Risk Assessment ◽  
Hazard Assessment ◽  
Human Health Risk ◽  
In Vitro Test ◽  
In Vitro Methods ◽  
New Concepts ◽  
Vitro Test

The title of this paper is challenging, because the question of how in vitro methods and results contribute to human health risk assessment is rarely considered. The process of risk assessment usually begins with hazard assessment, which provides a description of the inherent toxicological properties of the chemical. The next step is to assess the relevance of this to humans, i.e. the human hazard assessment. Finally, information on exposure is examined, and risk can then be assessed. In vitro methods have a limited, but important, role to play in risk assessment. The results can be used for classification and labelling; these are methods of controlling exposure, analogous to risk assessment, but without considering exposure. The Ames Salmonella test is the only in vitro method which is incorporated into regulations and used widely. Data from this test can, at best, lead to classification of a chemical with regard to genotoxicity, but cannot be used for classification and labelling on their own. Several in vitro test systems which assess the topical irritancy and corrosivity of chemicals have been reasonably well validated, and the results from these tests can be used for classification. The future development of in vitro methods is likely to be slow, as it depends on the development of new concepts and ideas. The in vivo methods which currently have reasonably developed in vitro alternatives will be the easiest to replace. The remaining in vivo methods, which provide toxicological information from repeated chronic dosing, with varied endpoints and by mechanisms which are not understood, will be more difficult to replace.

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