A Note on the Blood Analog for In-Vitro Testing of Heart Valve Bioprostheses

1984 ◽  
Vol 106 (2) ◽  
pp. 112-114 ◽  
Author(s):  
K. B. Chandran ◽  
B. Khalighi
Keyword(s):  
Heart Valves ◽  
Physiological Saline ◽  
Viscosity Coefficient ◽  
Test Fluid ◽  
Prosthetic Heart Valves ◽  
Glycerol Solution ◽  
Physiological Saline Solution ◽  
Tissue Heart Valves ◽  
Glycerine Solution

Glycerol solution with the viscosity coefficient similar to that of blood is used in evaluating the performance characteristics of prosthetic heart valves in the laboratory. However, physiological saline solution is used as a test fluid in testing tissue heart valves even though the viscosity coefficient does not match that of human blood. It is commonly believed that glycerol is absorbed by the tissue valves and hence the leaflets become stiff, making the test results invalid. However, in our laboratory a comparison of tissue valves exposed to glycerine solution at various times does not indicate any difference in the leaflet opening characteristics. Hence, it is suggested that glycerine solution be used as a test fluid for the evaluation of tissue valves also.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

The Effect of Dipyridamole and RA 233 on Human Platelet Function in Vitro

1973 ◽  
Vol 29 (03) ◽  
pp. 694-700 ◽  
Author(s):  
Paul L. Rifkin ◽  
Marjorie B. Zucker
Keyword(s):  
Mechanism Of Action ◽  
Human Blood ◽  
Glass Bead ◽  
Heart Valves ◽  
Human Platelet ◽  
Drug Effects ◽  
Simple Relation ◽  
Prosthetic Heart Valves ◽  
Induced Aggregation

SummaryDipyridamole (Persantin) is reported to prolong platelet survival and inhibit embolism in patients with prosthetic heart valves, but its mechanism of action is unknown. Fifty jxM dipyridamole failed to reduce the high percentage of platelets retained when heparinized human blood was passed through a glass bead column, but prolonged the inhibition of retention caused by disturbing blood in vitro. Possibly the prostheses act like disturbance. Although RA 233 was as effective as dipyridamole in inhibiting the return of retention, it was less effective in preventing the uptake of adenosine into erythrocytes, and more active in inhibiting ADP-induced aggregation and release. Thus there is no simple relation between these drug effects.

Noninvasive Electromagnetic Evaluation of Bjo¨rk-Shiley Heart Valves: Lifetime Prediction

2008 ◽  
Author(s):  
Raimond Grimberg ◽  
Adriana Savin ◽  
Shiu C. Chan ◽  
Rozina Steigmann ◽  
Lalita Udpa ◽  
...  
Keyword(s):  
Eddy Current ◽  
Heart Valves ◽  
Probability Of Detection ◽  
New Method ◽  
Lifetime Prediction ◽  
Prosthetic Heart Valves ◽  
In Vitro Experiments ◽  
Current Transducer ◽  
Eddy Current Transducer

Prosthetic heart valves of the Bjork-Shiley Convexo-Concave (BSCC) type have long been used extensively in implants; however, there have been reports of cases where one component of the valves failed, leading to the demise of the patient. This paper presents a new method for noninvasive electromagnetic evaluation for this type of valve, using an eddy current transducer with orthogonal coils. In vitro experiments have shown that discontinuities of outlet strut with depths equal or larger than 0.4mm can be detected with a probability of detection (POD) of 86.4%, and in the case of discontinuities with depth equal or larger than 0.6mm with POD of 97%.

Can the Hemodynamics of Prosthetic Heart Valves be Evaluated Sufficiently by In Vitro Tests?

1986 ◽  
pp. 47-54
Author(s):  
Martin Gottwik ◽  
S. Hartung ◽  
O. Epe ◽  
S. Langsdorf ◽  
J. Thormann ◽  
...  
Keyword(s):  
Heart Valves ◽  
In Vitro Tests ◽  
Prosthetic Heart Valves

Modeling Technique of Prosthetic Heart Valves

1984 ◽  
Vol 106 (1) ◽  
pp. 83-88 ◽  
Author(s):  
T. Kitamura ◽  
T. Kijima ◽  
H. Akashi
Keyword(s):  
Real Time ◽  
Heart Valves ◽  
Time Estimation ◽  
Modeling Technique ◽  
Computational Time ◽  
Prosthetic Heart Valves ◽  
The Real ◽  
Hemodynamic State ◽  
Real Time Estimation

This paper demonstrates a modeling technique of prosthetic heart valves. In the modeling, a pumping cycle is divided into four phases, in which the state of the valve and flow is different. The pressure-flow relation across the valve is formulated separately in each phase. This technique is developed to build a mathematical model used in the real time estimation of the hemodynamic state under artificial heart pumping. The model built by this technique is simple enough for saving the computational time in the real time estimation. The model is described by the first-order ordinary differential equation with 12 parameters. These parameters can be uniquely determined beforehand from in-vitro experimental data. It is shown that the model can adapt, with sufficient accuracy, to a change in the practical pumping condition and the viscosity of the fluid in their practical range, and is also demonstrated that the estimated backflow volume by model agrees closely with the actual one.

scholarly journals In-vitro and in-vivo antibacterial effect of Croton lobatus Linnaeus L. on two days post surgical wounds in rats

2019 ◽  
Vol 54 (2) ◽  
pp. 139-146 ◽  
Author(s):  
MA Kilani ◽  
AZ Hassan ◽  
ST Fadason ◽  
AM Obalowu ◽  
A Aliyu ◽  
...  
Keyword(s):  
Chronic Wounds ◽  
Water Extract ◽  
Dorsal Surface ◽  
Physiological Saline ◽  
Salmonella Spp ◽  
Albino Rat ◽  
Physiological Saline Solution ◽  
Antimicrobial Assay

Phytochemical constituents of Croton lobatus L. (C. lobatus) water extracts and quantitative analysis were carried out following standard procedures. The antibacterial activity against Staphylococcus aureus (ATCC 33591); Streptococcus Spp; Pseudomonas aeruginosa (ATCC 9028); Proteus vulgaris; Escherichia coli (ATCC 43895); and Salmonella Spp (ATCC 4932) was carried out at the concentration of 0.5g/mL, 0.05 g/mL and 0.00 5g/mL of water. In vivo antimicrobial assay was carried out by creating four wounds of 0.5 by 0.5 cm on dorsal surface of a male albino rat under anesthesia. The wounds were left for 48 hrs, after which they were accessed and samples were collected for culture, identification and colony forming unit counts (CFU). Respective treatment using dried C. lobatus, C. lobatus (water extract), Physiological saline solution and Cicatrin powder was carried out and samples were collected at day one, three, five and seven after initiation of treatments for CFU counts on nutrient and MacConkey agar. The phytochemical studies revealed that C. lobatus contains carbohydrates, glycoside, saponins, steroids, triterpenes, flavonoids, alkaloids and tannins. Croton lobatus L. showed a dose dependent activity against micro organisms with C. lobatus 0.5 inhibited the growth of most bacteria at the zone of inhibition ≤ 21mm. This was also supported by in vivo antimicrobial assay. Secondary metabolite tannins, triterpenoids, flavonoids, crotonic acids and saponin were responsible for its antimicrobial activity against the tested microorganisms thereby supporting its usage by the traditional medicine practitioner in Nigeria to treat chronic wounds. Bangladesh J. Sci. Ind. Res.54(2), 139-146, 2019

Corpus cardiacum stimulated trehalose efflux from cockroach (Periplaneta americana) fat body: control by calcium

1985 ◽  
Vol 63 (1) ◽  
pp. 63-66 ◽  
Author(s):  
J. E. Steele ◽  
T. Paul
Keyword(s):  
Cyclic Amp ◽  
Periplaneta Americana ◽  
Saline Solution ◽  
Fat Body ◽  
Surrounding Medium ◽  
Physiological Saline ◽  
Corpus Cardiacum ◽  
Physiological Saline Solution ◽  
Stimulation Of

Cockroach fat body incubated in a simple physiological saline solution releases trehalose to the surrounding medium. The output of trehalose occurs in the absence of ambient Ca2+ and decreases slowly with time. In two separate experiments, 0.1 mM CaCl2 added to the saline increased the output of trehalose on average by 70% but higher concentrations of Ca2+ did not further increase the efflux of trehalose. Stimulation of trehalose efflux by corpus cardiacum extract is absolutely dependent on extracellular Ca2+, no increase occurring beyond the basal level in the absence of the ion. The activity of corpus cardiacum extract increases as the concentration of CaCl2 is increased to 0.5 mM. This concentration of Ca2+ in the saline permits the extract to increase trehalose efflux by as much as 60% above the basal level. Corpus cardiacum extract, as well as the hypertrehalocaemic agents cyclic AMP and theophylline, increase significantly the influx of Ca2+ into fat body in vitro. The basal efflux of trehalose from fat body and that stimulated by corpus cardiacum extract is not dependent on extracellular Mg2+.

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