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R Alvarez

Publications and source records attributed to R Alvarez.

284 records · Page 16Linked to original sources
PubMedDate not supplied

[Dynamics of respiration and the microbial biomass in soil supplemented with straw from corn and soybeans].

Soil organic matter level has an important influence on land productivity. This level depends upon the efficiency in partitioning carbon from plant debris into CO2 and humified substances by microorganisms. The C/N ratio of the residues is one of the factors that affects this process. To study its influence on the growth and activity of the microflora, a soil from the corn region of Buenos Aires was supplemented with different amounts of straw from corn and soybean, and respiration and microbial biomass evolution were followed during four months. Biological activity of supplemented soils overcame control respiration during the first days of incubation, and intense cellular reproduction took place. Later, respiration decreased but biomass remained higher than in unamended soil until the end of the trial. When more carbonaceus material was added the microbial reproduction was faster, while the growth yield and the apparent residual carbon were lower; the C/N ratio of the biomass remained constant with all the treatments. The different nitrogen enrichment of the straw had no effect on the biological properties determined. However, soil mineral nitrogen content decreased in supplemented soils. The decrease of assimilatable nitrogen was stronger when more substrate was incorporated and when the C/N ratio was wider. These results suggest that soil supplies the necessary nitrogen for microbial growth and the straw quality has no effect on the activity and growth of microorganisms.

Argentina↗
PubMedDate not supplied

[The effect of nooglutil and piracetam on different forms of operant learning].

We studied effects of a new drug with nootropic action nooglutil (N-(5-hydroxynicotinoil)-L-glutaminic acid, OHK-10) on initial stages of different forms of operant behaviour in rats, namely avoidance learning in Shuttle box, in Skinner box and on T-maze reflex with water reward. Comparing dates resulted from these three methods permitted evaluation of effects of the drugs on learning. Both drugs had no effects on avoidance response in shuttle box and T-maze reflex with water reward. Nooglutil enhanced escape and avoidance responses meanwhile piracetam improved only escape response.

Animals↗
PubMedDate not supplied

[Autoimmune hepatitis with antibodies against liver cytosol (anti-LC1)].

Antibody against liver cytosol (anti-LC1) was proposed in 1988 as a new and very specific immunoserologic marker of autoimmune hepatitis of childhood and young age. In adults, anti-LC1 might be masked by the presence in serum of anti-LKM1, usually associated with antibodies to hepatitis-C virus. We report the case of a 60-year-old woman who had active chronic hepatitis not related to infection by hepatitis C virus, with autoantibody reacting against liver cytosol as the unique marker of autoimmune hepatitis. Treated with corticosteroids (prednisone, 1 mg/kg per day), coagulation disorder, bilirubin, transaminase activity and immunoglobulins normalized in the following months. A year and a half later, autoantibodies anti-LC1 and p-ANCAs were no longer detected. We have only found one report of a young patient with anti-LC1 autoimmune hepatitis who had cirrhosis and portal hypertension, in national publications.

Adult↗