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R Ulloa

Publications and source records attributed to R Ulloa.

5 recordsLinked to original sources
PubMed1987

Regulation by insulin of cyclic nucleotide phosphodiesterase (PDE) from rat luteal cells.

The effect of insulin on cyclic nucleotide phosphodiesterase (PDE) in rat luteal cells was studied. Cells were obtained from PMSG/hCG primed rats and further incubated or not with insulin. The hormone produced an increase of enzyme activity after a 10 min incubation of intact cells. Maximal stimulation was achieved at 0.2 nM of insulin. Two peaks of cyclic nucleotide phosphodiesterase activity were resolved after chromatography of cell cytosolic extracts on DEAE-cellulose. These peaks (I and II) were active with cAMP as substrate but only peak I was active with cGMP. The enzyme activity of both peaks was increased in cells treated with insulin. Phosphodiesterase activity in the two peaks show two kinetic components for cAMP hydrolysis, one of high affinity (Km 2-4 microM) and the other of low affinity (47-56 microM). Treatment of the cells with insulin produced a 2 to 8 fold increase of the Vmax of these peaks. In addition after stimulation with insulin, the activation of peak I phosphodiesterase by calmodulin was less effective.

Animals↗
PubMedDate not supplied

[Intestinal infection by parasites and/or hosts in school children of the IX region, Chile].

The prevalence of intestinal infection by parasites and/or commensals in primary school students from Lautaro, IX Region, was studied. The sample included 68 children from rural and 67 from urban areas. A Telemann modified method, Ziehl-Neelsen technique for Cryptosporidium sp. detection and Graham test were used. The results pointed out high rates of infections by protozoa and helminths (85.4%). There are no statistical differences related to origin for sex or scholarship. In the total sample, the more frequent parasite found was G. lamblia (37.8%); among the youngest was 60.7%. The second frequency was for T. trichiura (22.2%) and the third one for A. lumbricoides (12.6%). Among commensals the percentages were: E. coli 45.5% and E. nana 33.3%. It could be concluded that the intestinal infection by parasites and/or commensals in school children is endemic in the IX region, because the environmental conditions are appropriate for its permanence and transmission, specially in lower socioeconomical groups.

Adolescent↗