[Solitary kidney]. / Il rene solitario.

A functionally solitary kidney may be the consequence of renal agenesis, dysplasia, or surgical procedures. Compensatory hypertrophy and physiologic mechanisms intervene to preserve renal function. The authors discuss the physiopathology of solitary kidney in several clinical conditions.

New methods for detection of potential endocrine disruptors.

It has been hypothesized that recent adverse trends in humans are linked to an increased exposure to potential endocrine disrupting agents. These include widely used compounds that mimic the action of sex hormones, including bisphenol A, phthalates and parabens. Since the chemical structure is not sufficient to determine whether a chemical will act as an oestrogen, there is a need for assays that can determine whether a compound interferes with the endocrine systems. The Environmental Protection Agency has recently suggested a testing scheme, composed of an initial screening followed by a more comprehensive investigation of chemicals that are positive in the screening. The screening will use several short-term assays to screen many thousands of compounds for potential endocrine disrupting properties. However, none of these tests determines compound-induced effects on the expression of endogenous genes, which is the cause of the adverse effects. We propose to use a precise quantification of the expression levels of endogenous oestrogen-regulated genes to test whether a chemical has oestrogenic properties, and describe how an endogenous gene expression assay can be established and conducted. Furthermore, different applications of such an assay are discussed: in cell cultures; in experimental animals; or, optimally, directly in blood samples from exposed humans.

Long-term follow-up evaluation of magnetic resonance imaging in the prognosis of permanent GH deficiency.

OBJECTIVE: In patients with GH deficiency (GHD), magnetic resonance imaging (MRI) has revealed morphological abnormalities such as pituitary hypoplasia, pituitary stalk agenesis (PSA) and ectopia of the posterior pituitary (PPE). The MRI anomalies have been more frequently reported in patients with multiple pituitary hormone deficiency (MPHD) than in subjects with isolated GH deficiency (IGHD). The aim of this work was to define which MRI anatomical abnormalities of the hypothalamo-pituitary area can be considered as a prognostic marker of permanent GHD. DESIGN: To investigate the relationship between the neuroradiological images and endocrine findings, we clinically re-evaluated 93 out of the 121 GHD patients with IGHD and MPHD previously studied. RESULTS: No additional hormone deficiencies were observed in 55 out of 60 patients initially classified as having IGHD with a normal (15 cases) or reduced (40 cases) pituitary gland size, without other MRI abnormalities. The remaining five children, who had initially shown an apparently IGHD in spite of PSA and PPE, developed a MPHD over time. In 33 MPHD patients with (25 cases) or without (8 cases) MRI abnormalities, the associated hormone deficiencies were confirmed during follow-up. CONCLUSIONS: The IGHD patients showing PSA and PPE inevitably develop additional hormone deficiencies, while IGHD subjects having no MRI abnormalities maintain IGHD. Moreover, the anatomical abnormalities of the hypothalamo-pituitary area can be considered as a prognostic marker of permanent GHD.

End results in central precocious puberty with GnRH analog treatment: the data of the Italian Study Group for Physiopathology of Puberty.

We report some end results with GnRH agonist (GnRHa) treatment in central precocious puberty (CPP), in terms of final height (FH), ovarian function, peak bone mass, body composition and psychological problems. The two studies reported (Study I and II) are part of the activity of the Italian Study Group for Physiopathology of Puberty. Study L Growth data were analyzed of three groups of patients: treated with i.n. spray buserelin, i.m. triptorelin and untreated. Both GnRHa administration modes were effective in arresting pubertal development and all girls had complete recovery of the reproductive axis after therapy. Treated patients showed an improvement in final height in comparison with untreated patients and compared to predicted height at the start of treatment with both agonist treatments. However, patients treated with the long-acting slow release preparation had a better improvement in adult height and reached or exceeded the genetic height potential. Study II. In a retrospective evaluation of the outcome in 71 girls with idiopathic CPP treated with triptorelin, we found that FH fell within the population norm and the target range in 87.3% and 90% of the patients respectively. The tallest FH was recorded in the patients who started therapy at less than 6 years of age and in those who discontinued treatment at a bone age of 12.0-12.5 yr. Finally, we and other groups have recently found normal values of bone mineral density in girls at the end of GnRHa treatment in the great majority of patients.

[Growth hormone deficiency. Treatment with growth hormone and body composition]. / Déficit en hormone de croissance. Traitement par hormone de croissance et composition corporelle.

Increased fat mass, decreased lean mass, muscular mass and bone mineral density are characteristic of the body composition in GH deficiency, GH treatment reverses these abnormalities. Body composition was determined in 20 young adults with GHD diagnosed in childhood, whose GH treatment was stopped 1 year earlier. Reevaluation of GH secretion in these patients showed that 12 remained GH deficient (confirmed GHD) while eight recovered normal GH secretion (transient GHD). One year after stopping the GH treatment, patients with confirmed GHD showed an increased fat mass as compared with value at the end of the treatment; in addition a decreased bone mineral content was observed in the patients with low physical activity. There was no increased fat mass in transient GHD; however, these patients presented with low bone mineral content, as previously reported in adults with history of delayed growth and adolescence.

Determination of thyroxine in the hair of newborns by radioimmunoassay with high-performance liquid chromatographic confirmation.

Hair analysis is often used in forensic toxicology to study, retrospectively, chronic exposure of individuals to drugs, and consequently newborn hair may become an ideal sample to study intrauterine exposure to xenobiotics as well as to endogenous compounds. As a tool to investigate a supposed maternal thyroxine (T4) supply to the congenital hypothyroid fetus, we devised to use the analysis of T4 extracted from newborn hair. In the present paper, the analytical method based on T4 extraction from hair followed by a radioimmunoassay is described. To verify the nature of the T4-like immunoreactive material present in newborn hair, it was further studied by HPLC fractionation with radioimmunoassay of the eluted fractions. On the basis of a clear correspondence between retention times of T4 standard and T4-immunoreactive compound extracted from hair, we assigned this immunoreactive material to T4. Then, we determined T4 hair concentrations in 19 control newborns at birth and 12 congenital hypothyroid infants at 22 days of life. Values obtained from hypothyroid infants (31.47+/-8.8 pg/mg(hair), mean+/-S.D.) were not significantly lower than those obtained from healthy newborns at birth (36.10+/-13.2 pg/mg(hair)). Such results are in agreement with the hypothesis of a maternal supply of thyroxine to the fetus through placental crossing.

[Growth and renal function]. / Crescita e funzionalità renale.

Some genetic conditions, as cystinosis, familial hypophosphataemic rickets, type-I vitamin D-resistant rickets and renal tubular acidosis have an impact on growth and growth failure is one of the major problem in children with chronic renal failure (CRF). In early childhood, anorexia and malnutrition, electrolyte disturbances and metabolic acidosis are the main contributing factors for reduced growth, whereas renal osteodystrophy, anemia and hormonal disturbances are responsible for growth impairment later and during puberty. During infancy, loss of growth potential can be prevented by adequate nutrition. Later in life, catch-up growth cannot be induced by nutritional intervention or dialysis and renal transplantation allows catch-up growth in only a small percentage of patients. There is evidence for a state of resistance to growth hormone (GH) and insulin-like growth factor-I (IGF-I) in CRF. GH secretion is normal, but GH half-life is prolonged and the binding activity of the GH-binding protein is reduced, which points to a low receptor expression. IGF-I production may be diminished and the serum concentration of IGF-binding proteins (IGFBP-1 and 3) is increased. The imbalance between normal IGF-I and excessive IGFBP serum levels results in decreased IGF bioactivity that plays a pathogenic role in the growth failure. This insensitivity seems to be overcome by supraphysiological doses of recombinant human GH (rhGH). Many clinical studies have confirmed that rhGH increases growth velocity in children with CRF with and without dialysis and after renal transplant, without significant side-effects. The improvement of growth is more marked in prepubertal patients and during the first year of rhGH treatment. Long-term rhGH treatment in children with CRF improves the growth potential of children, achieving target adult height. The Authors discuss the recent studies employing rhGH in renal diseases and attempt to give some guide lines to rhGH treatment in these illnesses.