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J Nunez

Publications and source records attributed to J Nunez.

151 records · Page 9Linked to original sources
PubMedDate not supplied

Cyclic nucleotide phosphodiesterases, insulin and thyroid hormones.

The in vitro effects of insulin on different phosphodiesterase activities present in rat epididymal fat cells from normal and hypothyroid rats have been studied. Evidence is presented that insulin increases the maximum velocity of a particulate, low Km, cyclic adenosine-3', 5'-monophosphate (cyclic AMP) phosphodiesterase in both types of cells, this effect being more clearly evident with the fat cells from hypothyroid animals; combination of insulin and thyroidectomy resulted in a 400% stimulation with 10-10 - 10-9 M insulin. A clear and significant effect was apparent at 10-11 M insulin. However, the dose-response curve was biphasic, since stimulation by insulin was suppressed for doses of hormone higher 10-8 - 10-7 M. Moreover, insulin effects were very fast, since clear stimulation was observed after only 2 min of incubation; the maximal increase was obtained after 10 min. Insulin did not significantly affect the soluble cyclic AMP phosphodiesterase activity in normal cells, thus confirming results obtained by others. However, the soluble cyclic AMP phosphodiesterase activity was clearly stimulated by insulin when the fat cells were prepared from hypothyroid rats. Maximal stimulation was obtained with 10-9 M insulin; the response was again very fast. Soluble cyclic GMP phosphodiesterase activity was also increased additively by hypothyroidism and insulin, maximal stimulation being obtained with 10-9 M insulin. With this dose of insulin the additive effects of thyroidectomy and insulin produced a 5-fold stimulation. The effect of insulin on the soluble cyclic GMP phosphodiesterase was very fast (2-5 min). With both soluble cyclic nucleotide phosphodiesterase activities, insulin increased the maximal velocity but not apparent Km of the enzyme. Thus, hypothyroidism and insulin produced additive effects suggesting a different mechanism of action of these two hormonal situations on the degradation of the intracellular pools of cyclic AMP and cyclic GMP.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMedDate not supplied

Alopecia areata with features of loose anagen hair.

A child with alopecia areata (AA) presented initially with clinical features of loose anagen hair (LAH) and had features consistent with LAH on microscopic hair analysis. However, a scalp biopsy specimen demonstrated peribulbar inflammatory infiltrates characteristic of AA. We suggest that AA may mimic LAH clinically and a scalp biopsy may help in making the correct diagnosis.

Alopecia Areata↗
PubMedDate not supplied

[Proceedings: In vitro thyroid hormone formation (author's transl)].

Iodination of a non halogenated goiter thyroglobulin and the resulting thyroxinogenesis was studied in vitro with purified thyroid peroxidase, H2O2 generating system and various concentrations of iodide. The rate of iodination was linear during the first minutes of incubation but thyroxine synthesis only began after a lag period whatever the iodide concentration in the incubation medium was. With high iodide concentrations a highly iodinated thyroglobulin (40-50 iodine atoms) containing no thyroxine was obtained after 3 minutes of incubation. If this highly iodinated goiter thyroglobulin was purified and reincubated with peroxidase and H2O2, thyroxine synthesis was again observed only after a lag period (2-3 min). In the absence of iodide the enzyme to elicit thyroxine synthesis. Depending of its concentration free diiodotyrosine exerts two opposite effects on the reaction catalyzed by thyroid peroxidase : at high concentration (10(-4) M) in inhibition of thyroglobulin iodination, and at low concentration (10(-7), 10(-8) M) a stimulating effect on thyroid hormones biosynthesis.

Diiodotyrosine↗
PubMedDate not supplied

Why women don't get sterilized: a follow-up of women in Honduras.

In 1980, a study to determine interest in and access to sterilization for females was initiated at two Ministry of Health hospitals in Honduras. Results of the baseline study showed that 42 percent of women desiring sterilization from the Tegucigalpa hospital and 21 percent from the San Pedro Sula hospital had had a tubal ligation. A second study was conducted two years later, following up the interested but unsterilized women from the baseline study. Results show that 33 percent of women in the Tegucigalpa group, compared to 15 percent in the San Pedro Sula group, had been sterilized. Part of this difference can be attributed to an increase in sterilization facilities in Tegucigalpa over the two years after the baseline study was conducted. Among the major reasons women gave for not having been sterilized were financial and time constraints. Over the two-year period, the authors estimate that, of women interested in sterilization at delivery, 52 percent in total were sterilized in Tegucigalpa and 29 percent in San Pedro Sula.

Adult↗