The paper addresses laboratory preparation and antibacterial activity testing of kaolinite/nanoTiO2 composite in respect of the daylight irradiation time. Kaolinite/nanoTiO2 composites with 20 and 40 wt% of TiO2 were laboratory prepared, dried at 105 °C and calcined at 600 °C. The calcination caused transformation of kaolinite to metakaolinite and origination of the metakaolinite/nanoTiO2 composite. X-ray powder diffraction, Raman and FTIR spectroscopic methods revealed titanium dioxide only in the form of anatase in all evaluated samples (non-calcined and calcined) and also transformation of kaolinite to metakaolinite after the calcination treatment. Scanning electron microscopy was used as a method for characterization of morphology and elemental composition of the studied samples. A standard microdilution test was used to determine the antibacterial activity using four human pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa). A lamp with a wide spectrum bulb simulating daylight was used for induction of photocatalysis. The antibacterial assays found all the KATI samples to have antibacterial potency with different onset of the activity when calcined samples exhibited antibacterial activity earlier than the non-calcined. Significant difference in antibacterial activity of KATI samples for different bacterial strains was not observed.

• MeSH
• antibakteriální látky chemie   farmakologie   účinky záření   MeSH
• Bacteria účinky léků   MeSH
• časové faktory MeSH
• kaolin chemie   účinky záření   MeSH
• katalýza účinky záření   MeSH
• nanočástice chemie   účinky záření   MeSH
• nanokompozity chemie   účinky záření   MeSH
• povrchové vlastnosti MeSH
• světlo * MeSH
• titan chemie   účinky záření   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVE: Recent experimental studies point to a high reactivity of nanoparticles and the potential of sunscreens to penetrate the skin. We measured 20 markers of oxidative stress and inflammation to find out whether skin exposure to nanoTiO2 sunscreen may elevate the level of the markers in exhaled breath condensate (EBC) and urine of exposed subjects, as was suggested by our earlier study. METHODS: Six volunteers (3 males and 3 females), with a mean age of 48.0 ± 6.7 years, used commercial sunscreen for three days continuously. The first samples were collected before the test. The second samples were collected on day 4, before the sunscreen was washed off, and the third samples on day 11. The following biomarkers were measured: malondialdehyde, 4-hydroxy-trans-hexenal, 4-hydroxy-trans-nonenal, aldehydes C6-C12, 8-isoProstaglandin F2α, o-tyrosine, 3-chlorotyrosine, 3-nitrotyrosine, 8-hydroxy-2-deoxyguanosine, 8-hydroxyguanosine, 5-hydroxymethyl uracil, and leukotrienes B4, C4, D4, and E4, using liquid chromatography-electrospray ionisation-tandem mass spectrometry. RESULTS: In the urine, 4-hydroxy-trans-hexenal was significantly higher in post-exposure sample 2, and the same trend was seen in all urinary markers. In EBC, no difference was seen between the mean values of 20 post-test markers as compared with pre-test samples. CONCLUSION: This study suggests potential side effects of the sunscreen - borderline elevation of markers of oxidative stress/inflammation - which may relate to the absorption of the nanoTiO2, and the non-significant difference may be explained by the small number of subjects. The effect was not seen in EBC, where nanoTiO2 was not found. A larger study is needed, as according to our previous study, the beneficial effect of the sunscreen to suppress oxidative stress caused by UV radiation may be questioned.

• MeSH
• biologické markery chemie   MeSH
• dechové testy * MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• oxidační stres účinky léků   MeSH
• pilotní projekty MeSH
• přípravky chránící proti slunci * MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Nanoscale titanium dioxide (nanoTiO2) is a commercially important nanomaterial. Animal studies have documented lung injury and inflammation, oxidative stress, cytotoxicity and genotoxicity. Yet, human health data are scarce and quantitative risk assessments and biomonitoring of exposure are lacking. NanoTiO2 is classified by IARC as a group 2B, possible human carcinogen. In our earlier studies we documented an increase in markers of inflammation, as well as DNA and protein oxidative damage, in exhaled breath condensate (EBC) of workers exposed nanoTiO2. This study focuses on biomarkers of lipid oxidation. Several established lipid oxidative markers (malondialdehyde, 4-hydroxy-trans-hexenal, 4-hydroxy-trans-nonenal, 8-isoProstaglandin F2α and aldehydes C6-C12) were studied in EBC and urine of 34 workers and 45 comparable controls. The median particle number concentration in the production line ranged from 1.98 × 10(4) to 2.32 × 10(4) particles/cm(3) with ∼80% of the particles <100 nm in diameter. Mass concentration varied between 0.40 and 0.65 mg/m(3). All 11 markers of lipid oxidation were elevated in production workers relative to the controls (p < 0.001). A significant dose-dependent association was found between exposure to TiO2 and markers of lipid oxidation in the EBC. These markers were not elevated in the urine samples. Lipid oxidation in the EBC of workers exposed to (nano)TiO2 complements our earlier findings on DNA and protein damage. These results are consistent with the oxidative stress hypothesis and suggest lung injury at the molecular level. Further studies should focus on clinical markers of potential disease progression. EBC has reemerged as a sensitive technique for noninvasive monitoring of workers exposed to engineered nanoparticles.

• MeSH
• biologické markery analýza   moč   MeSH
• chemický průmysl MeSH
• dechové testy MeSH
• dinoprost analogy a deriváty   analýza   moč   MeSH
• lidé MeSH
• malondialdehyd analýza   moč   MeSH
• metabolismus lipidů MeSH
• monitorování životního prostředí metody   MeSH
• nanočástice analýza   toxicita   MeSH
• oxidace-redukce MeSH
• oxidační stres účinky léků   MeSH
• peroxidace lipidů účinky léků   MeSH
• poškození DNA MeSH
• pracovní expozice škodlivé účinky   analýza   MeSH
• spektrofotometrie atomová MeSH
• titan analýza   toxicita   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVES: Experimental studies using nanoscale TiO2 have documented lung injury, inflammation, oxidative stress, and genotoxicity. Human health data are extremely scarce. METHODS: In exhaled breath condensate (EBC) and urine of 22 office employees occupationally exposed to TiO2 during their visit in the production workshops for average 14±9 min/day a panel of biomarkers of nucleic acids and proteins oxidation was studied, specifically 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), 5-hydroxymethyl uracil (5-OHMeU), o-tyrosine (o-Tyr), 3-chlorotyrosine (3-ClTyr), and 3-nitrotyrosine (3-NOTyr). Examination was performed also in 14 comparable controls. RESULTS: The median respirable TiO2 mass concentration in the workshops was 0.40 mg/m3, median number concentration was 2.32×104 particles/cm3 with 80% of the particles being <100 nm in diameter. All 6 markers of oxidation were elevated in EBC in factory office employees relative to controls (p<0.01). Significant association was found between their job in TiO2 production plant and 5 markers of oxidation (except 3-NOTyr) in the EBC in multivariate analysis. No elevation of markers was detected in the urine. CONCLUSION: This pilot study suggests that even short nanoTiO2 exposure may lead to pulmonary oxidative stress; however this effect may be short-term and reversible. The clinical significance of these findings is unclear and more studies are needed.

• MeSH
• dospělí MeSH
• kovové nanočástice škodlivé účinky   MeSH
• látky znečišťující vzduch škodlivé účinky   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nemoci z povolání krev   MeSH
• oxidační stres * MeSH
• pilotní projekty MeSH
• pracovní expozice škodlivé účinky   MeSH
• titan škodlivé účinky   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Human health data regarding exposure to nanoparticles are extremely scarce and biomonitoring of exposure is lacking in spite of rodent pathological experimental data. Potential markers of the health-effects of engineered nanoparticles were examined in 30 workers exposed to TiO2 aerosol, 22 office employees of the same plant, and 45 unexposed controls. Leukotrienes (LT) B4, C4, E4, and D4 were analysed in the exhaled breath condensate (EBC) and urine via liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Fractional exhaled nitric oxide (FeNO) and spirometry was also measured. The median particle number concentration of the aerosol in the production ranged from 1.98  ×  10(4) to 2.32  ×  10(4) particles cm(-3); about 80% of the particles were  <100 nm in diameter. Median total mass concentration varied between 0.4 and 0.65 mg m(-3). All LT levels in workers' EBC were elevated relative to the controls (p  <  0.01). LTs in the EBC sample were correlated with titanium levels. Urinary LTs were not elevated in the workers and office employees. Office workers had higher LTB4 in EBC (p  <  0.05), and higher levels of FeNO (p  <  0.01). FeNO was higher in office employees with allergic diseases and was negatively correlated with smoking (p  <  0.01). In spirometry significant impairment in the workers was seen only for %VCIN and %PEF (both p  <  0.01). Multiple regression analysis confirmed a significant association between production of TiO2 and all cysteinyl LTs in EBC (p  <  0.01) and impaired %VCIN and %PEF (both p  <  0.01). LTB4 was also associated with smoking (p  <  0.01). LT levels complemented our earlier findings of DNA, protein, and lipid damage in the EBC of workers with nanoTiO2 exposures. Cysteinyl LTs in EBC analysis suggest inflammation and potential fibrotic changes in the lungs; they may be helpful for monitoring the biological effect of (nano)TiO2 on workers. Spirometry was not sensitive enough.

• MeSH
• aerosoly analýza   MeSH
• biologické markery analýza   MeSH
• dechové testy metody   MeSH
• dospělí MeSH
• koncentrace vodíkových iontů MeSH
• leukotrieny analýza   moč   MeSH
• lidé MeSH
• nanočástice škodlivé účinky   MeSH
• oxid dusnatý analýza   MeSH
• pracoviště MeSH
• pracovní expozice analýza   MeSH
• regresní analýza MeSH
• respirační funkční testy MeSH
• studie případů a kontrol MeSH
• tandemová hmotnostní spektrometrie MeSH
• titan škodlivé účinky   MeSH
• vydechnutí * MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH