Exogenous and endogenous antioxidants attenuate the lipid peroxidation in workers occupationally exposed to paints.

Occupational exposure to organic solvents present in paints is responsible for an increased production of reactive species, thus enabling the development of several diseases. Besides, both exo- and endogenous antioxidant defense systems are necessary to avoid oxidative tissue damage. This study investigated possible protective effects of the exo- and endogenous antioxidants on oxidative damage in painters occupationally exposed to organic solvents (n = 42) and controls (n = 28). Retinol, lycopene and ß-carotene were significantly lower in the exposed group. Despite the fact that blood toluene was below the biological exposure limits, malondialdehyde levels and antioxidant enzyme activities were increased, whereas reduced glutathione levels were decreased in painters, compared to nonexposed subjects. Moreover, multivariate regression models showed that reduced glutathione and carotenoids (mainly ß-carotene) have the major influence on lipid peroxidation (LPO). The present work suggests that the exogenous antioxidants, such as carotenoids, could protect occupationally exposed subjects to xenobiotics from LPO.

Blood thioredoxin reductase activity, oxidative stress and hematological parameters in painters and battery workers: relationship with lead and cadmium levels in blood.

Oxidative stress has been shown to be involved in lead and cadmium toxicity. We recently showed that the activity of the antioxidant enzyme thioredoxin reductase (TrxR) is increased in the kidneys of lead-exposed rats. The present study evaluated the blood cadmium and blood lead levels (BLLs) and their relationship with hematological and oxidative stress parameters, including blood TrxR activity in 50 painters, 23 battery workers and 36 control subjects. Erythrocyte δ-aminolevulinate dehydratase (δ-ALA-D) activity and its reactivation index were measured as biomarkers of lead effects. BLLs increased in painters, but were even higher in the battery workers group. In turn, blood cadmium levels increased only in the painters group, whose levels were higher than the recommended limit. δ-ALA-D activity was inhibited only in battery workers, whereas the δ-ALA-D reactivation index increased in both exposed groups; both parameters were correlated to BLLs (r = -0.59 and 0.84, P < 0.05), whereas the reactivation index was also correlated to blood cadmium levels (r = 0.27, P < 0.05). The changes in oxidative stress and hematological parameters were distinctively associated with either BLLs or blood cadmium levels, except glutathione-S-transferase activity, which was correlated with both lead (r = 0.34) and cadmium (r = 0.47; P < 0.05). However, TrxR activity did not correlate with any of the metals evaluated. In conclusion, blood TrxR activity does not seem to be a good parameter to evaluate oxidative stress in lead- and cadmium-exposed populations. However, lead-associated changes in biochemical and hematological parameters at low BLLs underlie the necessity of re-evaluating the recommended health-based limits in occupational exposure to this metal.

Main lepidopteran pest species from an eucalyptus plantation in Minas Gerais, Brazil.

Lepidoptera species were monitored in a plantation of Eucalyptus grandis in the Municipality of Bom Despacho, State of Minas Gerais, Brazil from March 1987 to February 1992. A total of 547 species were collected and divided in: primary pests: 13; secondary pests: 20; species without defined importance to eucalyptus: 79; and non-identified species: 435. These four groups had a mean of 5231.29; 338.18; 438.16 and 2222.87 individuals with a total of 8229.87 individuals collected per trap. The number of species without defined importance to eucalyptus, and non-identified species, increased during the collecting period of five years while those of primary and secondary pests showed similar numbers in all years. The most collected primary pests Thyrinteina arnobia Stoll and Stenalcidia sp. (Geometridae) showed higher frequencies during the driest and coldest periods of the year, whereas Psorocampa denticulata Schaus (Notodontidae) was most frequent during periods of higher rainfall. Species of groups III and IV increased in diversity with eucalyptus age. This area has a high probability of outbreaks of eucalyptus defoliating caterpillars, especially T. arnobia. For this reason, lepidopteran pests should be monitored in this plantation during the driest and coldest periods of the year, when they can reach population peaks.

In vivo toxicological evaluation of polymeric nanocapsules after intradermal administration.

Polymeric nanocarriers have shown great promise as delivery systems. An alternative strategy has been to explore new delivery routes, such as intradermal (i.d.), that can be used for vaccines and patch-based drug delivery. Despite their many advantages, there are few toxicity studies, especially in vivo. We report a safety assessment of biodegradable poly(ɛ-caprolactone) lipid-core nanocapsules (LNC) with a mean size of 245±10nm following single and repeated intradermal injections to Wistar rats. Suspensions were prepared by interfacial deposition of polymer. The animals (n=6/group) received a single-dose of saline solution (1.2ml/kg) or LNC (7.2×10(12)LNC/kg), or repeated-doses of two controls, saline solution or Tween 80 (0.9ml/kg), or three different concentrations of LNC (1.8, 3.6, and 5.4×10(12)LNC/kg) for 28 consecutive days. Clinical and physiological signs and mortality were observed. Samples of urine, blood, and tissue were used to perform toxicological evaluation. There were no clinical signs of toxicity or mortality, but there was a slight decrease in the relative body weights in the Tween 80-treated group (p<0.01) after repeated administration. No histopathological alterations were observed in tissues or significant changes in blood and urinary biomarkers for tissue damage. Mild alterations in white blood cells count with increases in granulocytes in the Tween-80 group (p<0.05) were found. Genotoxicity was evaluated through the comet assay, and no statistical difference was observed among the groups. Therefore, we conclude that, under the conditions of these experiments, biodegradable LNC did not present appreciable toxicity after 28 consecutive days of intradermal administration and is promising for its future application in vaccines and patch-based devices for enhancing the delivery of drugs.

Acute and subchronic toxicity evaluation of poly(ε-caprolactone) lipid-core nanocapsules in rats.

Owing to concerns over the effects of the physicochemical properties of nanoparticles and their interaction with biological systems, further investigation is required. We investigated, for the first time, the toxicity of lipid-core nanocapsules (LNCs) containing a polymeric wall of poly(ε-caprolactone) and a coating of polysorbate 80 used as drug delivery devices (~245nm) in Wistar rats after single- and repeated-dose treatments. The suspensions were prepared by interfacial deposition of the polymer and were physicochemically characterized. Toxicological effects were determined after single doses of 18.03, 36.06, and 72.12 × 10(12) LNC/kg and repeated doses of 6.01, 12.02, and 18.03 × 10(12) LNC/kg for 28 days by ip administration. The results for both the treatments showed no mortality or permanent body weight changes during the experiments. A granulomatous foreign body reaction was observed in the liver and spleen of higher dose groups in acute and subchronic treatments. Most of the hepatotoxicity and nephrotoxicity markers were within the reference values and/or were similar to the control group. However, a slight alteration in the hematologic parameters was observed in both the studies. Thus, to verify a possible methodological influence, we performed an in vitro test to confirm such influence. These findings are in agreement with earlier reports regarding no appreciable toxicity of biodegradable polymeric nanoparticles, indicating that LNC might be a safe candidate for drug delivery system. Furthermore, the results presented in this study are important for health risk assessment and to implement strategies for testing biodegradable polymeric nanoparticles.

Main lepidopteran pest species from an eucalyptus plantation in Minas Gerais, Brazil

Lepidoptera species were monitored in a plantation of Eucalyptus grandis in the Municipality of Bom Despacho, State of Minas Gerais, Brazil from March 1987 to February 1992. A total of 547 species were collected and divided in: primary pests: 13; secondary pests: 20; species without defined importance to eucalyptus: 79; and non-identified species: 435. These four groups had a mean of 5231.29; 338.18; 438.16 and 2222.87 individuals with a total of 8229.87 individuals collected per trap. The number of species without defined importance to eucalyptus, and non-identified species, increased during the collecting period of five years while those of primary and secondary pests showed similar numbers in all years. The most collected primary pests Thyrinteina arnobia Stoll and Stenalcidia sp. (Geometridae) showed higher frequencies during the driest and coldest periods of the year, whereas Psorocampa denticulata Schaus (Notodontidae) was most frequent during periods of higher rainfall. Species of groups III and IV increased in diversity with eucalyptus age. This area has a high probability of outbreaks of eucalyptus defoliating caterpillars, especially T. arnobia. For this reason, lepidopteran pests should be monitored in this plantation during the driest and coldest periods of the year, when they can reach population peaks.

De marzo de 1987 a febrero de 1992 se realizó un monitoreo con trampas luminosas en plantaciones de Eucalyptus grandis en Bom Despacho, Minas Gerais, Brasil. Se recolectaron 547 especies del orden Lepidoptera: plagas primarias: 13; plagas secundarias: 20; especies sin importancia definida para el cultivo de eucalipto: 79; y especies no identificadas: 435. Estos cuatro grupos tuvieron medias de 5231.29; 338,18; 438.16 y 2222.87 individuos por trampa respectivamente, para un total de 8229.87 lepidopteros recolectados por trampa. Durante los cinco años hubo un aumento del número de especies de los grupos III y IV. Las plagas primarias con mayor número de individuos fueron Thyrinteina arnobia Stoll y Stenalcidia sp. (Geometridae), con las mayores frecuencias para los meses más secos y fríos del año. Psorocampa denticulata Schaus (Notodontidae) fue más abundante en los periodos más lluviosos. La probabilidad de brotes de larvas desfoliadoras de eucalipto, principalmente T. arnobia, es alta en la región. Se recomienda hacer el monitoreo de lepidópteros plaga en los periodos más secos y fríos del año, cuando pueden presentar picos poblacionales.