As resistance of bacterial strains to antibiotics is a major problem, there is a need to look for alternative treatments. One option is antimicrobial photodynamic inactivation (aPDI). The pathogenic cells are targeted by a nontoxic photosensitizer while the surrounding healthy tissue is relatively unaffected. The photosensitizer is activated by light of t appropriate wavelength resulting in the generation of reactive oxygen species that are cytotoxic for the pathogens. In this work, the photosensitizer TMPyP and silver nanoparticles (AgNPs) were investigated for their synergistic antibacterial effect. We tested these two substances on two bacterial strains, methicillin-resistant Staphylococcus aureus 4591 (MRSA) and extended-spectrum beta-lactamases-producing Klebsiella pneumoniae 2486 (ESBL-KP), to compare their effectiveness. The bacteria were first incubated with TMPyP for 45 min or 5 h, then irradiated with a LED source with the total fluence of 10 or 20 J/cm2 and then placed in a microbiological growth medium supplemented with AgNPs. To accomplish the synergistic effect, the optimal combination of TMPyP and AgNPs was estimated as 1.56-25 μM for TMPyP and 3.38 mg/l for AgNPs in case of MRSA and 1.56-50 μM for TMPyP and 3.38 mg/l for AgNPs in case of ESBL-KP at 45 min incubation with TMPyP and fluence of 10 J/cm2. Longer incubation and/or longer irradiation led to a decrease in the maximum values of the photosensitizer concentration to produce the synergistic effect. From this work it can be concluded that the combination of antimicrobial photodynamic inactivation with a treatment including silver nanoparticles could be a promising approach to treat bacterial infection.

• MeSH
• antibakteriální látky farmakologie   MeSH
• antiinfekční látky * farmakologie   MeSH
• fotochemoterapie * metody   MeSH
• fotosenzibilizující látky farmakologie   MeSH
• Klebsiella pneumoniae MeSH
• kovové nanočástice * MeSH
• methicilin rezistentní Staphylococcus aureus * MeSH
• porfyriny * farmakologie   MeSH
• rezistence na methicilin MeSH
• stříbro farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH

• Publikační typ
• abstrakt z konference MeSH

Growing worldwide efforts to replace (reduce) animal testing and to improve alternative in vitro tests which may be more efficient in terms of both time, cost and scientific validity include also genotoxicity/mutagenicity endpoints. The aim of the review article was to summarize currently available in vitro testing approaches in this field, their regulatory acceptance and recommended combinations for classification of chemicals. A study using the combination of Comet Assay performed on two cell lines and the Chromosomal Aberration test on human peripheral lymphocytes was performed with the aim to predict the genotoxic potential of selected paraben esters, serving as a model chemical group. Parabens are widely used in consumer products as preservatives and have been reported to exhibit inconclusive results in numerous genotoxicity studies. The Comet Assay identified Ethylparaben and Benzylparaben as potentially genotoxic. The Chromosomal Aberration test revealed weak genotoxic potential in case of Ethylparaben and positive genotoxicity in case of Butylparaben, Propylparaben and Isopropylparaben. The main reasons for variability seem to be limited water solubility of parabens, determining their bioavailability at the cellular level, and absence of metabolic activation in the Comet Assay. The results confirmed that the Comet Assay should serve as a screening test and should not be used as a stand-alone method for classification of genotoxicity. The weight of evidence approach in risk assessment should be supported with data generated with the use of human relevant in vitro methods based on cells / tissues of human origin.

• MeSH
• alternativy testů na zvířatech * MeSH
• buněčné linie keratinocytů HaCaT MeSH
• chromozomální aberace chemicky indukované   MeSH
• hodnocení rizik MeSH
• kometový test MeSH
• lidé MeSH
• lymfocyty účinky léků   patologie   MeSH
• mikrojaderné testy MeSH
• mikrojádra chromozomálně defektní chemicky indukované   MeSH
• mutageneze účinky léků   MeSH
• parabeny toxicita   MeSH
• poškození DNA * MeSH
• testy genotoxicity * MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• srovnávací studie MeSH

Despite widespread and prolonged use of adult novelties, their health safety is not regularly tested or legally regulated. In the EU, adult novelties are subjected to the General Product Safety Directive, placing the burden of proof regarding safe products onto the manufacturers. The aim of our pilot study was to expand knowledge on potential application of in vitro methods for hazard prediction of extracts from final products. We subjected extracts of 20 adult novelties, purchased on the Czech market to toxicological tests including NRU cytotoxicity assay, sensitization tests DPRA and LuSens and the YES/YAS endocrine assay. Four samples produced cytotoxicity. Sensitization potential was recorded by DPRA (three samples) while the LuSens reported ten samples. Regarding endocrine disruption, three samples produced antiestrogen and antiandrogen effects. Six samples exhibited androgenic potential and one sample showed estrogenic potential. Positive results with possible health effects were recorded repeatedly for samples made of ABS, PVC and latex. The study has confirmed promising usefulness of our test methods combination with regard to safety testing of this type of consumer products. The results should be evaluated with care, however, the data bring added-value to the limited knowledge of mixture toxicology and are indicative for further testing.

• MeSH
• buňky BALB 3T3 MeSH
• endokrinní disruptory toxicita   MeSH
• fibroblasty účinky léků   fyziologie   MeSH
• hra a hračky * MeSH
• lidé MeSH
• myši MeSH
• pilotní projekty MeSH
• plastické hmoty toxicita   MeSH
• Saccharomyces cerevisiae účinky léků   fyziologie   MeSH
• sexuální chování účinky léků   fyziologie   MeSH
• spotřebitelská bezpečnost produktů normy   MeSH
• techniky in vitro metody   MeSH
• testy akutní toxicity metody   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Silver nanoparticles (AgNPs) have been widely studied for their beneficial antimicrobial effect and have been considered by some to be a safe ingredient, as penetration of metal nanoparticles through the skin in vivo has not been proven. However, AgNPs are becoming a commonly applied nanomaterial for surface modifications of medical products which come into contact with damaged skin. In our experiments, we tested two commercially available AgNPs samples manufactured by electrolysis. AFM was used to characterize tested AgNPs morphology and their mean particle size which was assessed as 30.6nm and 20.4nm. An important mechanism of AgNPs cytotoxicity is generation of reactive oxygen species (ROS), chemically reactive species containing oxygen. Although ROS occur in cell metabolism naturally, their overproduction can induce oxidative stress - imbalance between production and antioxidant defenses. This can be associated with cytotoxicity and DNA damage. Conventional in vitro tests were used to evaluate the cytotoxic potential and DNA damage in BJ human fibroblasts cell lines. We found that both tested AgNPs samples induced ROS generation and caused the DNA damage in fibroblasts. One of the key concerns about the association with cytotoxic or genotoxic responses of nanoparticles is the capability of these materials to penetrate through cellular membrane. Cellular uptake studies were performed using Raman imaging as a label-free microscopic technique. In combination with a univariate image analysis, results demonstrate cellular uptake and distribution of the AgNPs which were taken up by BJ cells within 24h of incubation in a growth medium. The study demonstrates the potential of Raman imaging to unambiguously identify and localize AgNPs in fixed cells.

• MeSH
• buněčné linie MeSH
• fibroblasty metabolismus   MeSH
• kovové nanočástice * MeSH
• lidé MeSH
• Ramanova spektroskopie MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• stříbro metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH