RESUMEN

The human lung adenocarcinoma epithelial (A549) cells and the human embryo lung (HEL 12469) cells were used to investigate the uptake and cytotoxicity of magnetite nanoparticles (MNPs) with different chemically modified surfaces. MNPs uptake was an energy-dependent process substantially affected by the serum concentration in the culture medium. Internalized MNPs localized in vesicle-bound aggregates were observed in the cytoplasm, none in the nucleus or in mitochondria. All MNPs induced a dose- and time-dependent increase in cytotoxicity in both human lung cell lines. The cytotoxicity of MNPs increased proportionally with the particle size. Since the cytotoxicity of MNPs was nearly identical when the doses were equalized based on particle surface area, we suppose that the particle surface area rather than the surface modifications per se underlay the cytotoxicity of MNPs. In general, higher internalized amount of MNPs was found in HEL 12469 cells compared with A549 cells. Accordingly, the viability of the human embryo lung cells was reduced more substantially than that of the adenocarcinoma lung cells. The weak MNPs uptake into A549 cells might be of biomedical relevance in cases where MNPs should be used as nanocarriers for targeted drug delivery in tumor tissue derived from alveolar epithelial cells.

Asunto(s)

RESUMEN

An improved antioxidant status (overthreshold plasma values of essential antioxidants) minimizes the oxidative damage. The levels of antioxidant vitamins C and E, ,,antioxidant" trace elements selenium, zinc, copper and iron were measured in two groups of adults with different nutritional habits--alternative (vegetarians; n=110) and traditional (mixed diet, control, n=101). The prevalence of iron and zinc deficiencies was found in the alternative group (20% vs 11%--iron, 13% vs 9%--zinc) as a consequence of higher intake of plant trace element absorption inhibitors. As opposed to the latter, the control group had higher findings of iron and copper levels over the optimal range (18% vs 8%--iron, 11% vs 2%--copper). The subjects on mixed diet was showed a significant negative linear correlation between serum zinc and iron levels. This favourable relationship means a decrease in Fenton reaction by indirect zinc effect. Average plasma values of vitamin C, vitamin C/vitamin E, vitamin E/ cholesterol (LDL protection), vitamin E/triacylglycerols (polyunsaturated fatty acid protection) in vegetarians are over the threshold with high number of individual overthreshold values (94% vs 17%--vitamin C, 100% vs 58%--vitamin C/vitamin E, 89% vs 68%--vitamin E/cholesterol, 100% vs 64%--vitamin E/triacylglycerols). Homocysteine levels in vegetarians (36% atherogenic levels) correlate significantly inversely to vitamin C levels, the fact of which means a positive vitamin C effect in free radical remove also in hyperhomocysteinemia. Plant food is a rich source of antioxidants. A correct vegetarian nutrition or optimized mixed diets with regular and frequent consumption of protective food commodities may be an effective contribution to the age-related chronic degenerative disease prevention. (Tab. 2, Fig. 2, Ref. 31.).

Asunto(s)

RESUMEN

Dietary antioxidant levels in the blood depend on intake of fruits and vegetables and therefore might be expected to show seasonal variation. A group of healthy male subjects in Bratislava, Slovakia gave blood samples each month for 1 year. Vitamin C, alpha- and gamma-tocopherol and several carotenoids were measured in plasma, and concentrations of essential metals zinc, copper and selenium in serum. Oxidative DNA damage was assessed in lymphocytes using the comet assay. Seasonal variations in antioxidant levels did not follow a common pattern. beta-Cryptoxanthin was highest in the spring. Lycopene peaked in late summer. Lutein/zeaxanthin was higher in summer than in winter. The concentration of zinc in serum was higher in winter than in summer. DNA damage was lower in summer than in winter. Selenium as well as several antioxidants correlated negatively with indices of DNA damage, while zinc levels showed a positive correlation with DNA damage. These results provide some support for a link between consumption of antioxidants and protection against DNA oxidation.

Asunto(s)

RESUMEN

Total mercury concentrations (as a sum of vapor and particulate mercury) were measured in 24-h samples of ambient air in 20 different localities of the Slovak Republic eight times during the period 1996-1997. Vapor mercury was analyzed on site by atomic fluorescence with amalgamation technique. Particulate mercury was determined by vapor hydride atomic absorption spectrometry after wet digestion of filters with particulate air samples. The results showed that 34% of the 160 individual total mercury concentrations exceeded 5 ng/m3--the ambient air quality guideline value recommended by the WHO. The range of total mercury concentrations in the ambient air of Slovakia was: 1.13-3.98 ng/m3 (geom. mean 2.63) in the background area; 2.25-5.27 ng/m3 (geom. mean 3.64) in the agricultural areas; 1.73-20.53 ng/m3 (geom. mean 4.57) in the urban areas; and 1.53-39.85 ng/m3 (geom. mean 5.28) in the industrial areas. The highest mercury levels occurred in areas with metallurgical industry and coal combustion. The predominant form of mercury present in air was vapor mercury. The particulate fraction of mercury in ambient air (as a percentage of total mercury) varied widely from 0.4% to 42.1% (geom. mean = 4.4%). This fraction was lower in agricultural areas (2.3%) than in urban areas (5.3%). Although the atmospheric vapor mercury concentrations were slightly higher in summer than in winter, a direct correlation of vapor mercury concentrations and ambient air temperature was not found. Furthermore, the particulate mercury concentrations did not correlate with total particulate levels.

Asunto(s)

Asunto(s)

Asunto(s)

RESUMEN

The levels of mercury in water, soil, plants, poultry and poultry products, fish, dustfall as well as in total daily diet of apprentices were measured. The main purpose of our study was to estimate the average daily intakes of mercury.

Asunto(s)

RESUMEN

In 1986 and 1987 the authors investigated the incidence of diseases of the respiratory system in children in 13 areas with a contaminated atmosphere. The morbidity was compared with the incidence of diseases in children living in an area with a relatively clean living environment. In 1986 the group comprised 8,973 children, in 1987 9,409 children aged 7-14 years. The morbidity was recorded by health community paediatricians according to the International Classification of Diseases and evaluated by means of the annual incidence. The authors calculated also the mean period of illness of the airways. In 11 contaminated areas they found a significantly higher incidence of respiratory diseases (p less than 0.01) and higher mean duration of respiratory diseases, as compared with the control area.

Asunto(s)