Acetaldehyde is an environmentally widespread genotoxic aldehyde present in tobacco smoke, vehicle exhaust and several food products. Endogenously, acetaldehyde is produced by the metabolic oxidation of ethanol by hepatic NAD-dependent alcohol dehydrogenase and during threonine catabolism. The formation of DNA adducts has been regarded as a critical factor in the mechanisms of acetaldehyde mutagenicity and carcinogenesis. Acetaldehyde reacts with 2'-deoxyguanosine in DNA to form primarily N(2)-ethylidene-2'-deoxyguanosine. The subsequent reaction of N(2)-ethylidenedGuo with another molecule of acetaldehyde gives rise to 1,N(2)-propano-2'-deoxyguanosine (1,N(2)-propanodGuo), an adduct also found as a product of the crotonaldehyde reaction with dGuo. However, adducts resulting from the reaction of more than one molecule of acetaldehyde in vivo are still controversial. In this study, the unequivocal formation of 1,N(2)-propanodGuo by acetaldehyde was assessed in human cells via treatment with [(13)C(2)]-acetaldehyde. Detection of labeled 1,N(2)-propanodGuo was performed by HPLC/MS/MS. Upon acetaldehyde exposure (703 μM), increased levels of both 1,N(2)-etheno-2'-deoxyguanosine (1,N(2)-εdGuo), which is produced from α,β-unsaturated aldehydes formed during the lipid peroxidation process, and 1,N(2)-propanodGuo were observed. The unequivocal formation of 1,N(2)-propanodGuo in cells exposed to this aldehyde can be used to elucidate the mechanisms associated with acetaldehyde exposure and cancer risk.

Background: Gastric cancer is the second cause of cancer death worldwide and the first cause in Chile. Management of this pathology is controversial. Aim: To report the results on morbidity, mortality, and long-term survival rates of surgical treatment of gastric cancer, and compare them with those reported in the literature. Material and Methods: Follow up of 423 patients (aged 16 to 88 years, 271 males) operated for a gastric adenocarcinoma between 1996 and 2002. Patients were staged with the 5 th edition of TNM staging system, and the 2 nd edition in English of the Japanese Classification of Gastric Cancer. Morbidity was assessed using the classification of the Memorial Kettering Cancer Center group. Kapplan-Meier method was used to assay survival, and Log rank Test to compare long-term survivals. Results: Resectability of the lesions was 70.4%, and 88% of them corresponded to a curative-intended surgery. Seventy percent of patients were in stage TNM IIIA or higher at the moment of surgery. Mortality in curative intended operated patients was 4.2%, and morbidity was 33.7%. Overall five years survival rate was 33%: In the group with curative intended surgery it was 52%. Two years survival rate in the non intended curative group was 3.4%. Conclusions: The reported incidence of complications in our series is similar to that reported in the literature. Five year survival rates, morbidity and mortality were comparable to those reported abroad (Rev Méd Chile 2007; 135: 687-95). (

A pulsed Nd:YAG laser operating on the fourth (266 nm) and second (532 nm) harmonics has been used to generate plasmas on the target surface in air at atmospheric pressure. The influence of wavelength on quantitative analysis of 4 minor elements in stainless steel samples (Si, Ti, Nb and Mo) was investigated. Stainless steel samples with different elemental concentrations were prepared and analyzed by laser-induced plasma spectrometry (LIPS). The effect of laser wavelength on analytical figures of merit (calibration curves, correlation coefficients, linear dynamic ranges, analytical precision, and accuracy values) was found to be negligible when internal standardization (an Fe line) and time-resolved laser-induced plasma are employed. For both wavelengths, the calibration curves presented a good linearity and an acceptable linear dynamic range in the concentration interval investigated. For the four elements studied, limits of detection lower than 150 microg g(-1) were achieved. To evaluate the influence of wavelength on precision and accuracy, a set of fifteen high-alloyed steel samples from different stages of steelmaking process have been analyzed. Finally, the long-term stability of the analytical measurements for Mo with 532 nm wavelength has been discussed. RSD values were lower than 5.3% for the elements studied.

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