Critical parameters in cultivation of experimental biofilms using the example of Pseudomonas fluorescens

AbstractFormation and treatment of biofilms present a great challenge for health care and industry. About 80% of human infections are associated with biofilms including biomaterial centered infections, like infections of prosthetic heart valves, central venous catheters, or urinary catheters. Additionally, biofilms can cause food and drinking water contamination. Biofilm research focusses on application of experimental biofilm models to study initial adherence processes, to optimize physico-chemical properties of medical materials for reducing interactions between materials and bacteria, and to investigate biofilm treatment under controlled conditions. Exploring new antimicrobial strategies plays a key role in a variety of scientific disciplines, like medical material research, anti-infectious research, plant engineering, or wastewater treatment. Although a variety of biofilm models exist, there is a lack of standardization for experimental protocols, and designing experimental setups remains a challenge. In this study, a number of experimental parameters critical for material research have been tested that influence formation and stability of an experimental biofilm using the non-pathogenic model strain of Pseudomonas fluorescens. These parameters include experimental time frame, nutrient supply, inoculum concentration, static and dynamic cultivation conditions, material properties, and sample treatment during staining for visualization of the biofilm. It was shown, that all tested parameters critically influence the experimental biofilm formation process. The results obtained in this study shall support material researchers in designing experimental biofilm setups.

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Efficiency of pharmacogenetic approach to anticoagulant therapy in patients with prosthetic heart valves

Kardiologiia ◽

10.18087/cardio.n681 ◽

2019 ◽

Vol 59 (9S) ◽

pp. 25-30

Author(s):

E. V. Gorbunova ◽

V. V. Rozhnev ◽

A. V. Ponasenko ◽

Olga Leonidovna Barbarash

Keyword(s):

Anticoagulant Therapy ◽

Therapeutic Range ◽

Heart Valves ◽

Warfarin Therapy ◽

Molecular Genetic ◽

Time Frame ◽

Prosthetic Heart Valves ◽

Main Diagnosis ◽

Mechanical Prostheses ◽

Time Required

Background. This study examined clinical, demographic, anthropometric, and inheritance factors that influence individual sensitivity to warfarin therapy after heart valve surgery. The clinical significance of the pharmacogenetic approach was assessed using the individual time frame and time spent in the INR therapeutic range. Aims. We determined the clinical outcome of the pharmacogenetic approach at the start of warfarin therapy in patients with prosthetic heart valves. Materials and methods. The study included 915 patients, of which 512 women and 403 men (mean age 56±10 years), living in Western Siberia. Rheumatic heart disease was the main diagnosis that caused the acquired defect. Mechanical prostheses were used in 70% of cases of cardiac surgery. Real-time polymerase chain reaction used for molecular genetic testing. Results. The frequencies of the alleles and genotypes of CYP2C9 and VKORC1 in the study population of patients with heart valves prosthetic correspond to the distribution in Caucasoid populations. The use of pharmacogenetic testing results at the beginning of warfarin therapy reduced the time required for selecting a therapeutic dose of anticoagulant by 2 times and increased the duration of stay in the INR therapeutic range by 20.2%. Conclusion. The use of the pharmacogenetic approach at the begin‑ ning of warfarin therapy contributes to the effectiveness and safety of anticoagulant therapy in this category of patients.

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

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648112 ◽

1973 ◽

Vol 29 (03) ◽

pp. 694-700 ◽

Cited By ~ 4

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.

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