The urea cycle was evaluated in perfused livers isolated from cachectic tumor-bearing rats (Walker-256 tumor). Urea production in livers of tumor-bearing rats was decreased in the presence of the following substrates: alanine, alanine + ornithine, alanine + aspartate, ammonia, ammonia + lactate, ammonia + pyruvate and glutamine. Urea production from arginine was higher in livers of tumor-bearing rats. No difference was found with aspartate, aspartate + ammonia, citrulline, citrulline + aspartate and glutamine + aspartate. Ammonia consumption was smaller in livers from cachectic rats when the substance was infused together with lactate and pyruvate. Glucose production was smaller in the cachectic condition only when alanine was the gluconeogenic substrate. Blood urea was higher in tumor-bearing rats, suggesting higher rates of urea production. The availability of aspartate seems to be critical for urea synthesis in the liver of tumor-bearing rats, which is possibly unable to produce this amino acid in sufficient amounts from endogenous sources. The liver of tumor-bearing rats may have a different exogenous substrate supply of nitrogenous compounds. Arginine could be one of these compounds in addition to aspartate which seems to be essential for an efficient ureogenesis in tumor-bearing rats.

In this paper the classical ELISA test was used, which is a highly sensitive method, with the objective of estimating the anti-Paracoccidioides brasiliensis antibodies level in healthy people, residing in supposedly endemic regions for PCM, Northwest Paran State, Brazil. The sera was analyzed from 680 blood donors' who were approved by the classical serologic screening by blood banks. Four cities were studied (Campo Mour o, Maring , Cianorte and Umuarama) with a sample of 170 donors each. The antigen used was Ag7days, diluted serum 1/400, anti human IgG-conjugate marked with peroxidase and revealed with O-Phenylenediamine. It was possible to detect 181 (27%) sera with antibody level above the cut off threshold. The percentage varied between the cities. These results allied with the favorable climatic and geographical conditions and also previous reports of PCM indigenous to the region, indicate that the Northwest of Paran is an endemic region for PCM.