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Biomedical subjects

B Giron

Publications and source records attributed to B Giron.

5 recordsLinked to original sources

Expression of Sox8, Sox9 and Sox10 in the developing valves and autonomic nerves of the embryonic heart.

We describe the expression pattern of Sox8, Sox9 and Sox10 during the development of the chick embryo heart. These Sox genes constitute the group E of the large Sox family of transcription factors. We show that the expression of Sox8, Sox9 and Sox10 in the developing heart correlates with heart septation and with the differentiation of the connective tissue of the valve leaflets. Sox10 appears also as a specific marker of developing heart nerves. These findings fit with the occurrence of morphological and functional anomalies of the heart reported in humans deficient for Sox9 and Sox10.

Animals↗

Insulin and free fatty acid levels during oral glucose tolerance tests and their relation to age in 70 healthy children.

In 70 healthy children aged from three months to 15 years, blood glucose, immunoreactive insulin, and free fatty acids were measured during a three-hour glucose tolerance test. The results are presented for the whole group as well as for three age groups: three months-five years, six-10 years, and 11-15 years. It is demonstrated that (1) glucose levels are significantly lower in young children (younger than five years); (2) there are no significant age-related changes in free fatty acid concentration; (3) insulin levels are increasing constantly and significantly with age, the most strikingly at the age of onset of puberty; the absence of notable changes in glucose tolerance results in a rise of the I/G ratio as well. The causes for the increase of insulin secretion with age, whether of peripheral or pancreatic order, are still speculative.

Adolescent↗

In vitro secretion of gastrin, insulin, and glucagon in tissue cultures of pancreas from a child with neonatal intractable hypoglycemia.

Small pieces of pancreatic tissue were obtained at surgery from a subtotal pancreatectomy performed in a 45-day-old child suffering from intractable neonatal hyperinsulinic hypoglycemia. Histological examination was performed using aldehyde fuchsin, Grimelius', and Hellerström-Hellman's stainings, and immunoperoxidase labeling of insulin and gastrin. The pancreatic tissue before explantation showed numerous and sometimes hyperplastic islets, together with isolated insulin-, glucagon-, and gastrin-containing cells scattered among the exocrine tissue, in aspects similar to "B cell nesidioblastosis." These features could be interpreted as an acinoinsular transformation and/or an embryonic malformation. Extralobular endocrine islet formation by budding from ductular structures was evoked, suggesting the persistency of embryonic properties. The pieces were cultivated on rooster plasma coagulum covered with culture medium. In vitro, endocrine cells survived for 43 days, with outgrowth from the explant and with retention of their secretory abilities. After each medium renewal, radioimmunoassays were performed on the culture medium; they showed that insulin and glucagon secretions decreased with time. On the contrary, secretion of immunoreactive gastrin progressively increased, and kept up to 43 days, with subcultures. Some explants developed in a peculiar way, outgrowing as epithelial layers rich in gastrin-secreting cells as indicated by radioimmunoassays performed after they were reexplanted.

Cell Movement↗