Low levels of hepatic cytochrome P-450 in Mexicans with uncomplicated cholelithiasis.

The multienzymatic complex known as cytochrome P-450 represents one of the most important hemoprotein families of the liver. It participates in the metabolism of steroids, fatty acids, prostaglandins and liposoluble vitamins, and also plays a role in the bioactivation of xenobiotic compounds (generates reactive metabolites which produce acute and chronic lesions in liver tissue). This is a report on the low concentrations of total microsomal P-450 (0.093 +/- SD = 0.069 nMoles/mg protein) found in liver biopsies of 19 mexican patients diagnosed as having biliary lithiasis, as compared to an anglosaxon population with the same liver pathology (0.415 +/- 0.105 nMoles/mg protein). These low values are in agreement with the observation of a high incidence in normal mexicans (91.7%) of poor nifedipine metabolizers. Our findings justify an analyses of hepatic RNAm and cDNA of mexican individuals according to ethnic background, diet and environmental contaminants.

Verapamil does not block the spastic response of Praziquantel on the larvae of Taenia pisiformis.

This paper describes that the previous addition of Verapamil does not block the spastic response to Praziquantel (Pz) in larvae of Taenia pisiformis kept in vitro, where opposite results were found in the literature using mammalian tissue. It is possible that Pz stimulates other Ca++ transport channels not sensitive to Verapamil action and promotes Ca++ liberation from calcareous corpuscles stimulating phospholipase C of the tegument surface generating inositol triphosphate. These hypotheses require experimental approaches to define the exact mechanism of action.

Presencia de esterasas y peptidasas en el tegumento intacto de vesiculas de Cysticercus cellulosae. / Presence of esterases and peptidases in the intact tegument of vesicles of Cysticercus cellulosae

En este informe se describe el comportamiento de seis hidrolasas relacionadas con el tegumento intacto de las vesiculas de C. cellulosae analizadas por espectrofotometria utilizando equipos comerciales que liberan grupos cromogenos a 405 nm. Las actividades guardan relacion lineal con el numero de vesiculas y el tiempo de exposicion. Los valores representan la actividad relativa comparada con el suero humano normal, y corresponden a la de una vesicula. La acetilcolinesterasa (1,800 U/I) es de 10 a 20 veces mas activa que la seudocolinesterasa (0.5 U/ml); la fosfatasa acida representa la enzima de mayor actividad (30 mU/ml), mientras que la fosfatasa alcalina (2.5 U/1) la gamma - glutamil transferasas (3.0 U/1) y la leucilamino-peptidasa (3.5 U/1) muestra los niveles mas bajos