Identification of ring Y chromosome: cytogenetic analysis, Southern blot and fluorescent in situ hybridization.

A young male with a 45, X/46, X, r(Y)/47, X, r(Y), r(Y)/48, X, r(Y), r(Y), r(Y) karyotype was described. The phenotype was substantially characterized by short stature (< 3rd centile) and by a scrotal hypospadias with a normal sized penis. Fluorescent in situ hybridization (FISH) and molecular analysis by X and Y chromosomes specific probes were performed to identify the origin of the marker chromosomes which had been impossible to define by conventional and high resolution cytogenetics techniques.

[Study of the beta cell function in type I diabetes by the determination of peptide C after glucagon challenge].

In 35 patients (13F/22M; age range 2-15 years), affected by insulin dependent diabetes mellitus (IDDM), basal and glucagon stimulated C peptide was determined and correlated with the daily insulin requirement (U/Kg/die), the glycosylated hemoglobin (HbA1c), the age of onset (months) and the length of the illness (months). The results of C peptide determinations are illustrated in tab. 1: in 20 patients (group I) the basal value of C peptide is higher than 1 ng/ml and increases after glucagon load; in 15 patients (group II) the basal value of C peptide is lower than 1 ng/ml; in 9 ones (group IIA) of these 15 a glucagon load does not elicit a residual insulin secretion; in the other 6 ones (group IIB) a significative C peptide increase is observed after glucagon load.