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Biomedical subjects

F Buzi

Publications and source records attributed to F Buzi.

43 records · Page 3Linked to original sources

Physiological growth hormone secretion during slow-wave sleep in short prepubertal children.

The usefulness of a limited nocturnal GH profile has been evaluated for the assessment of physiological GH secretion. We have analysed the complete overnight GH and sleep profiles of 20 short prepubertal children, sampled at 15-min intervals. The mean age was 9.1 years (range 4.3-11.7 years) and mean height velocity standard deviation score (SDS)-1.0 (range -2.4 to +0.4). The sleep stage in which the maximal GH value was reached varied considerably between the patients. Only 55% achieved the maximal GH value during the first slow-wave sleep period, and 65% in the first 2 h of sleep. The maximal values during the first slow-wave period correlated weakly with the sum of the nocturnal peak values and the total area under the curve of the complete GH profile. None of these parameters correlated with height velocity. We conclude that at present there is no substitute for complete overnight or 24 h GH profiles for the assessment of physiological GH secretion, but the clinical significance of the variations seen remains unclear.

Body Height↗

Growth hormone bioactivity and immunoactivity in tall children.

In subjects with constitutional tall stature, both low and high GH response to stimulation tests have been observed when measured by commercial kits. To investigate the reason for these conflicting results, we evaluated growth hormone (GH) secretion using different assays as well as GH-binding protein and insulin-like growth factor-I (IGF-I) concentrations in tall children. Serum samples were collected from 22 prepubertal constitutionally tall children, aged 2.87-13.25 years, during two pharmacological tests to evaluate serum GH levels measured by both immunofluorometric assay (IFMA) and the Nb2 cell bioassay. Serum IGF-I values were evaluated by RIA. Circulating low affinity (LA) and high affinity (HA) GH-binding proteins (GHBPs) were evaluated by FPLC gel filtration. Considering the highest serum GH levels as measured by IFMA, the 22 tall subjects were divided into two groups: group A including 16 children with blunted serum GH peak levels (5.78+/-0.68 ng/ml) and group B including 6 subjects with normal serum GH peak values (15.73+/-1.56 ng/ml). No differences were observed in serum GH peak levels as measured by the Nb2 cell bioassay between group A (14.77+/-1.54 ng/ml) and group B (16.03+/-1.96 ng/ml), and between both groups and 11 age-and sex-matched controls (12.25+/-1.19 ng/ml). In group A, the Nb2 cell bioassay/IFMA ratio of serum GH peak levels (0.29+/-0.08) was significantly higher (p<0.05) than in group B (0.07+/-0.01). No differences were found in serum LA-GHBP and HA-GHBP as well as in IGF-I concentrations between the 16 patients of group A and the 6 of group B. Likewise, no difference in auxological parameters was found between the two groups. The biological activity of GH evaluated using the Nb2 cell bioassay is similar in tall children with a low GH response as measured by IFMA in comparison with those with a normal GH response, and is in agreement with both the auxological data and serum IGF-I concentrations.

Adolescent↗

Pseudohypoaldosteronism: report of a case presenting as failure to thrive.

We report a 2 month-old infant referred for failure to thrive. At birth, weight was 3820 g and length 52 cm. After physiologic weight loss, the patient showed no further weight gain for the next two months. On admittance (age 2 mo), weight was 3340 g and length 53 cm; the infant had severe dystrophy, generalized hypotonia and dehydration; blood chemistry showed hyponatremia, hyperkalemia and hypochloremia. A salt losing syndrome of adrenal origin was hypothesized. However, rehydration and hydrocortisone administration failed to correct hyponatremia and hyperkalemia. Endocrine assessment showed high levels of aldosterone and plasma renin activity, suggesting pseudohypoaldosteronism. Oral sodium chloride supplementation normalized electrolyte balance and the patient showed progressive weight gain and catch-up growth, confirming the diagnosis.

Administration, Oral↗

McCune-Albright syndrome: a longitudinal clinical study of 32 patients.

We report the diagnostic clinical features and their long term evolution in 32 patients with McCune-Albright syndrome. Patient data are made up of two periods: the first, classified as personal history, is from birth until the time when the diagnosis of McCune-Albright syndrome was made; the second, classified as clinical observation, is from the first observation until the end of follow up. The total duration of these two periods was 9.6+/-2.9 yr; mean age at first observation was 5.7 yr (range 0.7-11 yr). The probability of manifesting main clinical signs according to age was calculated: almost all had skin dysplasia at birth, 50% probability of peripheral precocious puberty in females at 4 years and 50% of bone dysplasia at 8 years of age were found. Other clinical signs had diagnostic relevance when preceding the main signs leading to diagnosis of McCune-Albright syndrome even without specific genetic investigation. The most important clinical manifestations have different evolutions: skin lesions increase in dimensions according to body growth; precocious puberty in females evolves rapidly but periods of regression can be seen in some patients; bone dysplasia in most patients evolves with an increase both in the number of affected bones and in the severity of lesions.

Child↗