India currently has the largest number of indoor air pollution-related health problems in the world, with three-quarters of its households burning wood, cowdung, or crop residues ("traditional" biomass fuels) for cooking, and the remainder using kerosene and relatively clean-burning liquefied petroleum gas (LPG). Combustion of these fuels produces various pollutants that may cause serious health effects in exposed populations. In this study, the micronucleus (MN) and chromosomal aberration (CA) assays were used to evaluate the relative amounts of DNA damage produced by the use of these cooking fuels. Cytogenetic evaluation of 179 female subjects showed a significant increase in both MN and CA frequency in blood lymphocytes from users of biomass-fuels in comparison to lymphocytes from LPG users (used as a reference population). The relative MN and CA frequencies for the users of the various fuels decreased in the order cowdung > cowdung/wood >/= wood > kerosene >/= LPG. Further, the results indicated an effect of subject age, and the duration of exposure on the MN and CA frequencies in biomass fuel users. Age had no significant effects on the genotoxicity responses in subjects with 10 years, CA and MN frequencies were higher in older individuals (>30 years of age) than younger subjects. Regardless of age, subjects burning biomass fuels had higher MN and CA frequencies than LPG users only when exposures were of at least 5 years duration. These results indicate that burning biomass-based fuels increases the frequency of cytogenetic alterations in blood lymphocytes of exposed populations, possibly because of exposure to the various noxious gases and toxic substances present in biomass fuels. These cytogenetic markers could be used in the field to assess the genotoxic consequences of burning various cooking fuels and for early detection of genetic abnormalities in people exposed to various pollutants and toxicants.

Asbestos and its carcinogenic properties have been extensively documented. Asbestos exposure induces diverse cellular events associated with lung injury. Previously, we have shown that treatment with chrysotile shows significant alteration in phase I and phase II drug metabolizing enzyme system. In this study we have examined some potential mechanisms by which garlic treatment attenuates chrysotile-mediated pulmonary toxicity in rat. Female Wistar rats received an intratracheal instillation of 5 mg chrysotile (0.5 mL saline) as well as intragastric garlic treatment (1% body weight (v/w); 6 days per week). Effect of garlic treatment was evaluated after 1, 15, 30, 90, and 180 days by assaying aryl hydrocarbon hydroxylase (AHH), glutathione (GSH), glutathione S-transferase (GST), and production of thiobarbituric acid reactive substances (TBARS) in rat lung microsome. The results showed that AHH and TBARS formation were significantly reduced at day 90 and day 180 in chrysotile treated garlic cofed rats; GSH recovered 15 days later to the near normal level and GST elevated significantly after treatment of garlic as compared to chrysotile alone treated rat lung microsome. The data obtained shows that inhibition of AHH activity and induction of GST activity could be contributing factor in chrysotile-mediated pulmonary toxicity in garlic cofed rats. However, recovery of GSH and inhibition of TBARS formation by garlic and its constituent(s) showed that garlic may give protection by altering the drug metabolizing enzyme system.

Asbestos was monitored in water, sediment, and aquatic plant samples around an asbestos cement factory. Based on asbestos concentration found in aquatic plants during monitoring, and the propensity of asbestos to cause oxidative stress in animal models, laboratory experiments were conducted to assess toxicity of chrysotile asbestos on an aquatic macrophyte, duckweed (Lemna gibba). L. gibba plants were exposed to two concentrations of chrysotile asbestos (0.5 microg and 5.0 microg chrysotile in 5.0 microl double distilled water) twice per week during a period of 28 days and cultured in medium containing 0.1 g chrysotile/L. Control plants were cultured in medium without chrysotile asbestos. Effect of chrysotile exposure on certain growth and physiological and biochemical parameters was evaluated. An inhibition effect of chrysotile exposure was found on the number of fronds, root length, and biomass. Similar alterations in contents of chlorophyll, carotenoid, total free sugar, starch, and protein were also found. Contrary to effect on these parameters, a dose- and time-dependent increase in efflux of electrolytes, lipid peroxidation, cellular hydrogen peroxide, catalase, and superoxide dismutase activity was found. The results indicate oxidative stress and phytotoxicity of chrysotile asbestos on duckweed.

No abstract

No abstract