Biomedical subjects

K Kejlová

Publications and source records attributed to K Kejlová.

4 recordsLinked to original sources

PubMed2005

Phototoxicity of bituminous tars-correspondence between results of 3T3 NRU PT, 3D skin model and experimental human data.

Bituminous tars (Ichthammol and Ichthyol Pale) are widely used in pharmaceutical, veterinary and cosmetic industries for their anti-microbial, anti-inflammatory and anti-pruritic effects. In contrast to coal tar, no phototoxicity of bituminous tars has been reported in man, although both Ichthammol and Ichthyol Pale exhibit UV absorption which is higher and broader for the former. The validated 3T3 NRU phototoxicity test indicated phototoxic potential of both substances. The phototoxicity test in a 3D human skin model (EpiDerm) only confirmed phototoxicity for Ichthammol. Human data on Ichthammol phototoxicity are missing. A photopatch test in human volunteers was performed in order to clarify the discrepancy between the phototoxicity found in the skin model and the absence of reported human phototoxicity. Following 4h exposure to 5% and 10% aqueous solutions of Ichthammol and Ichthyol Pale the test sites were irradiated with a UVA dose of 5 J/cm(2). Early phototoxic reaction (erythema) within 4-6h after irradiation was only elicited by Ichthammol and not by Ichthyol Pale. These data correspond well with those from the 3D skin model test and suggest the necessity to employ several test systems for final phototoxicity assessment. In addition to the results obtained in 3T3 NRU PT, further testing on 3D skin models may better reflect bioavailability of a given chemical in the skin, relevant to the situation in humans.

Adult↗

PubMed2005

Hydrophilic polymers--biocompatibility testing in vitro.

Biocompatibility is one of the main prerequisites for safe use of medical devices. Estimation of cytotoxicity is a part of the initial evaluation laid down in ISO standards on biological evaluation of medical devices. Hydrophilic polymers (based on 2-hydroxyethyl methacrylate HEMA) doped by addition of selected additives with antioxidant and/or free radical scavenging potential (vitamin C and hindered amine stabilizer N-(2,2,6,6-tetramethylpiperidin-4-yl)methacrylamide) were tested in different in vitro systems (3T3 Balb/c cell culture and a 3D human skin model) for biocompatibility and suitability for use as wound dressings. The results of the 3T3 NRU cytotoxicity test using both the direct and indirect contact approaches and a 3D skin model modified irritation test (EpiDerm) confirmed high biocompatibility and good skin tolerance of both the basic polymers and those enriched with specific additives up to a balanced level. HEMA polymer showed a beneficial effect against cytotoxicity of an irritant (sodium dodecyl sulfate). The in vitro biocompatibility test results were confirmed by human local skin tolerance testing.

Adult↗

PubMedDate not supplied

In vitro toxicity testing of supramolecular sensitizers for photodynamic therapy.

We report the phototoxicity of meso-tetrakis(4-sulphonatophenyl)porphine (TPPS4) and zinc metallocomplex (ZnTPPS4) sensitizers in the presence or absence of 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) on G361human melanoma cells. Morphological changes in cell cultures have been evaluated using inversion fluorescent microscope and image analysis. Viability of cells was determined by means of molecular probes for fluorescence microscopy (LIVE/DEAD kit- double staining with Calcein AM and Ethidium Homodimer). The quantitative changes of cell viability in relation to sensitizers concentrations and irradiation doses were proved by fluorometric measurement with fluoroscan Ascent. We found that the most effective sensitizer is ZnTPPS4 bound to HP-beta-CD, since the IC50 value was 12.5 g/ml at the dose of light radiation of 10 J/cm2.

Cell Line, Tumor↗

PubMedDate not supplied

The benefits of the 3T3 NRU test in the safety assessment of cosmetics: long-term experience from pre-marketing testing in the Czech Republic.

We have introduced the 3T3 NRU cytotoxicity test for methodological, economical and ethical reasons as a regular part of tier pre-marketing testing to assess local tolerance of raw materials for cosmetics, household chemicals and final cosmetic products. Using the 3T3 cell line according to the standard INVITTOX protocol No.64 (NRU Assay) the borderline concentration, relevant to the highest tolerated dose, is determined for each material. The toxic effect is reached at different concentration levels specific for individual cosmetics categories, depending on their chemical characteristics. Typical ranges of cytotoxicity for specific categories of cosmetics were established after testing of hundreds of materials. The range lies between 1 microg/ml (anti-dandruff shampoos), up to 2000 microg/ml (toothpastes and mouthwashes). The 3T3 NRU cytotoxicity test is a sensitive tool able to identify more aggressive products, that are also more likely to evoke irritation in human skin. It was even possible to detect protective effects of one natural herbal ingredient. The comparative study of cytotoxicity test results and human patch test results from a group of essential oils is presented. Cytotoxicity tests represent a highly ethical approach for estimation of irritancy. On the basis of in vitro test results suggesting low risk we can proceed to confirmatory tests in human volunteers.

3T3 Cells↗