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J Pou

Publications and source records attributed to J Pou.

26 records · Page 2Linked to original sources
PubMed1986

Effects of tolbutamide pretreatment on the rate of conversion of newly synthesized proinsulin to insulin and the compartmental characteristics of insulin storage in isolated rat islets.

Tolbutamide (1 g/kg body wt) was administered to male rats for 3 days to determine the effects of this pretreatment on subsequent insulin biosynthesis and compartmental storage characteristics of freshly isolated islets. Islets were isolated 16 h after the last tolbutamide administration, at a time when fed plasma glucose concentrations were normal. Islet glucagon was unchanged but insulin content was significantly reduced (38 +/- 1.2 ng IRI/islet from seven untreated rats versus 7.9 +/- 1.2 ng IRI/islet from eight treated rats). After tolbutamide pretreatment, the rate of incorporation of 3H-leucine into islet proinsulin was unchanged, but the t1/2 of labeled proinsulin-to-insulin conversion was significantly (P less than 0.001) decreased from 36 to 20 min. After treatment, actual rates of glucose-stimulated insulin secretion were 50% lower, however, because due to the proportionately greater depletion of islet insulin content, the fractional rate of secretion was increased two-fold. After treatment, there was evidence of compartmental, heterogeneous insulin storage, and glucose still marked newly synthesized insulin for preferential release; however, the differential release of new and old insulin converged rapidly with time. Mathematical integration of the data suggested dilution of the newly synthesized insulin compartment with unlabeled insulin during the chase period, but additionally indicated more rapid mixing of newly synthesized with previously stored, unlabeled insulin. Thus, tolbutamide-treated rats partially compensated for acute insulin depletion by increasing the rate of proinsulin-to-insulin conversion, but not increasing the rate of proinsulin biosynthesis; doubling the glucose-stimulated fractional secretory rate of the depleted cellular insulin storage compartment; and retaining compartmental storage characteristics but mixing newly synthesized insulin more rapidly with the compartment of previously stored, unlabeled insulin.

Animals↗
PubMed1984

[Mediterranean boutonneuse fever in children. Study of 139 cases].

A prospective study of 139 children suffering mediterranean spotted fever, all of them hospitalized during the summer time of the last five years is presented. Clinical features were high fever, maculopapulous rash and black eschar ("tàche noire"). Among analytical findings, leucocyte count was decreased in a 38.8% of children during the first week of illness. Weil-Felix test was positive in 47.2% for OX-2 and 52.7% for OX-19 of cases. The indirect immunofluorescence for rickettsial conorii was positive in 100% of cases in the second determination. 74.1% of patients received antimicrobial therapy and 25.9% symptomatic treatment. All children cured without complications.

Adolescent↗
PubMed1984

Effects of monensin on conversion of proinsulin to insulin and secretion of newly synthesized insulin in isolated rat islets.

When isolated rat islets were incubated with 10(-10) - 10(-6) M monensin, a sodium and proton ionophore, glucose-stimulated insulin release was inhibited in a concentration- and time-dependent manner. After removal of monensin, inhibition of insulin secretion persisted during stimulation with a variety of secretagogues, including 5 mM glucose plus 15 mM arginine, 20 mM glucose, and 20 mM glucose plus 1 mM 3-isobutyl-1-methylxanthine. Within the same low range of monensin concentrations, proteolytic conversion of newly synthesized proinsulin to insulin was also blocked. At each concentration, prohormone-to-hormone conversion was inhibited to almost the same extent as inhibition of insulin secretion. Therefore, both processes may have equal or common dependency on a subcellular ionic gradient. Although monensin decreased total insulin secretion, the glucose-regulated marking process was unaffected. Regardless of the monensin concentration or the overall rate of insulin secretion, the percentage of secreted newly synthesized versus older insulin remained the same, and the threefold differences in the fractional secretory rates of newly synthesized versus total insulin also remained the same. Thus, rather than specifically blocking protein traffic through the Golgi apparatus of the beta cell, monensin probably first inhibited insulin secretion by disrupting proton gradients in secretory vesicles and, thereby, also inhibited other processes occurring within this organelle.

1-Methyl-3-isobutylxanthine↗
PubMed1982

[Hematemesis in childhood. Use of the fiberscope in diagnosis].

Authors report the results of utilization of fiberscope (FEC) in pediatric patients with hematemesis. They emphasize the utility of this method, its high percentage of positivity in the diagnostic in relation to the precocity of the FEC and the high incidence of hemorrhage gastritis in relation to salycilates ingest.

Adolescent↗