Activity of Ceftaroline against Aerobic Gram-Positive and Gram-Negative Pathogens: Effect of Test Method Variability

Ceftaroline is a new cephalosporin with bactericidal activity against methicillin-resistant S. aureus (MRSA) as well as gram-negative pathogens. Variations of in vitro test conditions were found to affect ceftaroline activity, with 5% NaCl inhibiting growth and/or reducing the minimum inhibitory concentrations (MICs) for E. coli, K. pneumoniae, M. catarrhalis, H. influenzae, and streptococci, while an inoculum of 106 CFU/mL raised MICs of some E. coli, K. pneumoniae, and M. catarrhalis strains.

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A New in vitro Test Method for Calcification of Bioprosthetic Heart Valves

The International Journal of Artificial Organs ◽

10.1177/039139889702000506 ◽

1997 ◽

Vol 20 (5) ◽

pp. 267-271 ◽

Cited By ~ 17

Author(s):

B. Glasmacher ◽

M. Deiwick ◽

H. Reul ◽

H. Knesch ◽

D. Keus ◽

...

Keyword(s):

Heart Valves ◽

Test Method ◽

In Vitro Test ◽

Bioprosthetic Heart Valves ◽

Porcine Tissue ◽

Test Conditions ◽

Phosphate Depletion ◽

Vitro Test ◽

Identical Test

To investigate the calcification behavior of different bioprosthetic heart valves and verify possible hypotheses of the etiology of valve calcification, an accelerated pulse tester for bioprostheses was developed, whereby up to ten valves can be tested under identical test conditions. Each valve was mounted in a separate compartment on a piston and cyclically moved through a calcifying solution at frequencies of up to 800/min at 37°C. An appropriate calcifying solution was evaluated by incubation tests of bovine and porcine tissue. Calcification was confirmed by measuring Ca and phosphate depletion by atomic absorption spectroscopy, von Kossa staining, EDAX, and microradiography. The first tests were successfully carried out on porcine valves that had been nondestructively assessed for tissue/stress anomalies by holographic interferometry prior to the calcification test. The tests showed that 75% of irregular fringe pattern areas corresponded to the calcification areas.

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Wear characteristics of an unconstrained lumbar total disc replacement under a range of in vitro test conditions

Journal of Biomedical Materials Research Part B Applied Biomaterials ◽

10.1002/jbm.b.33456 ◽

2015 ◽

Vol 105 (1) ◽

pp. 46-52 ◽

Cited By ~ 4

Author(s):

Philip J. Hyde ◽

John Fisher ◽

Richard M. Hall

Keyword(s):

Total Disc Replacement ◽

Disc Replacement ◽

In Vitro Test ◽

Wear Characteristics ◽

Lumbar Total Disc Replacement ◽

Test Conditions ◽

Vitro Test

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Development of an in vitro test procedure for the characterization of left atrial appendage occluder devices

Current Directions in Biomedical Engineering ◽

10.1515/cdbme-2019-0116 ◽

2019 ◽

Vol 5 (1) ◽

pp. 461-463

Author(s):

Finja Borowski ◽

Sebastian Kaule ◽

Stefan Siewert ◽

Klaus-Peter Schmitz ◽

Michael Stiehm ◽

...

Keyword(s):

Left Atrial ◽

Left Atrial Appendage ◽

Standardized Test ◽

Test Procedure ◽

Test Method ◽

Atrial Appendage ◽

In Vitro Test ◽

Watchman Device ◽

Vitro Test

AbstractThe implantation of an occluder in the left atrial appendage (LAA) is an emerging therapy for the treatment of patients suffering from atrial fibrillation and with a contraindication to oral anticoagulation. The LAA occluder (LAAO) provides a reduction of the potential risk of strokes by thromboembolism. Currently, only a few CE-approved devices are available on the market and the number of clinical trials is comparatively low. Furthermore, there is currently no standardized test method available for testing functionality of the occluder, especially for testing safe anchorage and permeability. Therefore, the aim of this study is to establish an in vitro test method to prove anchorage mechanism and permeability regarding thromboembolism of the LAAO under physiological conditions. A standardized technical and fully parameterized silicone model of a LAA, based on studies of different morphologies and sizes, was developed. The LAA model was mounted onto the left atrial chamber of a commercial pulse duplicator system to simulate physiological hemodynamic conditions. The test was performed using the Watchman device (Boston Scientific, USA; size: 31 mm). The inner implantation diameter of the LAA model was designed according to a target compression of 10% for the Watchman device in the implanted configuration. Furthermore, thrombus-like particles (n=150, d=1,7±0,05 mm) were added to represent the flushing of thrombi out of the LAA after device implantation. Within several cycles it was confirmed that no particles were washed out of the LAA model with the implanted occluder leading to a full protection against thromboembolism. It could also be shown that the occluder is firmly anchored in the LAA. Pressure measurements with sensors in the left atrium and in the LAA distal to the occluder could also show that the occluder has no influence on the pressure conditions in the LAA.

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