Showing papers by "National University of Comahue published in 1985"

Cholinesterase activities in developing amphibian embryos following exposure to the insecticides dieldrin and malathion.

Abstract: The exposure of toad (Bufo arenarum) embryos to dieldrin2 and malathion3 produced an inhibition of acetyl (AChE) and butyryl (ChE) cholinesterase. Dieldrin treatment induced hyperactivity in the swimming larvae; malathion showed no detectable behavioral effects.In vivo adsorption of dieldrin by the oocyte produced delayed toxicity in the embryo.In vitro inhibition of AChE was not significant; 47.3 mg/L of malathion in the medium interrupted embryogenesis, but 0.47 mg/L permitted the embryo to complete their development without the appearance of any observable malformations.

Cardiotoxicity as a result of 5-fluorouracil therapy.

Abstract: We report the case of a patient bearing a sigmoid colon carcinoma, stage IV, who after 11 months of antiblastic therapy, having completed a dose of 81,000 mg of 5-FU and CCNU, suffered a myocardial infarct We attribute this complication to 5-FU Due to the fact that the coronary angiogram did not confirm the arteriosclerotic nature of the lesion, we suggest that it could have been caused by an endoarteritis, resulting from an immuno-allergic or toxic cumulative process

Anomalous Geomagnetic Field Behavior Recorded by Glacial Sediments from Northwestern Patagonia, Argentina

Abstract: Glacial sediments and two volcanic flow units from northwestern Patagonia, Argentina were sampled for paleomagnetic measurements as part of an ongoing program to date and correlate the glacial stratigraphy. Samples taken from a large ball and pillow structure in the Anfiteatro Moraine are normal polarity and pass the fold test suggesting that the magnetization was locked in prior to the formation of the structure. Samples from Pichileufu-age glaciolacustrine sediments have anomalously low inclinations and show little movement of the magnetic vector over a 400 to 500 year period if rhythmites are interpreted to be varves. Tills in the Malleo valley, 120km north of Bariloche, that are tentatively correlated with the Pichileufu-age sediments are bracketed by normal polarity basalt flows from Pino Santo and Volcan Lanin. Anisotropy of magnetic susceptibility results from the Pichileufu and Anfiteatro Moraine sediments indicate that both units have a primary depositional fabric. A redeposition experiment of Pichileufu lake sediment suggests that it is capable of recording steep inclination geomagnetic fields. The Pichileufu sediments are interpreted to have recorded anomalous low inclination geomagnetic field behavior which is not characterized by the dramatic looping usually associated with geomagnetic excursions or polarity transitions. These observations may be explained by local dominance of a standing focus of the nondipole field for at least 400 to 500 years in the early- to mid-Brunhes normal polarity epoch.