Hypoxemic and ischemic tolerance in emperor penguins.

Oxygen store depletion and a diving bradycardia in emperor penguins (Aptenodytes forsteri) expose tissues to critical levels of hypoxemia and ischemia. To assess the prevention of re-perfusion injury and reactive oxygen species (ROS) damage in emperor penguins, superoxide radical production, lipid peroxidation (thiobarbituric acid reactive substances (TBARS)), and antioxidant enzyme activity profiles in biopsy samples from muscle and liver were determined and compared to those in the chicken and 8 species of flighted marine birds (non-divers and plunge divers). In muscle of emperor penguins, superoxide production and TBARS levels were not distinctly different from those in the other species; among the antioxidant enzymes, catalase (CAT) and glutathione-S-transferase (GST) activities were significantly elevated above all species. In the liver of emperor penguins, TBARS levels were not significantly different from other species; only CAT activity was significantly elevated, although GST and glutathione peroxidase (GPX) activities were 2-3 times higher than those in other species. The potential for ROS formation and lipid peroxidation is not reduced in the pectoral muscle or liver of the emperor penguin. Scavenging of hydrogen peroxide by CAT and the conjugation of glutathione with reactive intermediates and peroxides by GST and GPX appear to be important in the prevention of ROS damage and re-perfusion injury in these birds.

Bilateral anorchia in infancy: occurence of micropenis and the effect of testosterone treatment.

OBJECTIVE: To analyze the clinical and histological findings in boys with bilateral anorchia and the response to testosterone treatment on penis length. STUDY DESIGN: Patients were divided into two groups according to the absence (group A, n = 29) or the presence (group B, n = 26) of palpable intrascrotal or inguinal mass at first clinical examination. RESULTS: A micropenis was found in 46% of patients (n = 24) with a similar proportion in both groups. Testosterone treatment induced a mean penis length gain of 1.9 +/- 1.3 SDS (standard deviation score). However, micropenis persisted in six patients. Histological examination (n = 18) confirmed the absence of any testicular structure with deferent ducts being present unilaterally or bilaterally in all but three patients. In these three patients, a hemorrhagic testis, probably as a result of a mechanical torsion, was found. CONCLUSIONS: The presence of isolated micropenis in almost half of patients with bilateral anorchia strongly suggests that the testicular damage frequently occurs during the second half of gestation after male sexual differentiation. In most cases, testosterone treatment stimulates the penile growth. Although the pathogenesis of bilateral anorchia may be heterogeneous, our study suggests that gonads may have been functionally abnormal before they disappeared, and suggests that some patients have an intrinsic endocrine disorder.

Do all girls with apparent idiopathic precocious puberty require gonadotropin-releasing hormone agonist treatment?

OBJECTIVE: To evaluate prospectively pubertal and predicted adult height progression until final height (FH) or near FH in girls with apparent idiopathic precocious puberty who were not treated. STUDY DESIGN: The decision not to treat at the time of initial evaluation was based on evidence of slowly progressive puberty as shown by bone age (BA) advancement <2 years above the chronologic age, whatever the hypothalamic pituitary ovarian axis activation, or no evidence of hypothalamic pituitary ovarian axis activation, whatever the BA advancement. During follow-up, patients who showed a significant decrease in predicted FH were treated with gonadotropin-releasing hormone agonist. RESULTS: Twenty-six girls with idiopathic precocious puberty were studied at a mean chronologic age of 7.4 +/- 0.9 years during a follow-up period of 6.6 +/- 2.2 years until FH or near FH. During the first 2 years of follow-up, most of the patients (group 1, n = 17; 65% of the cases) showed no substantial changes in predicted FH. They never required treatment, and menarche occurred at a mean chronologic age of 11.9 +/- 0.6 years. Their mean FH (or near FH) at 160.7 +/- 5.7 cm was close to their target height (161.3 +/- 4.7 cm). On the other hand, after a mean follow-up period of 1.4 +/- 0.8 years, 9 patients (group 2) had acceleration of bone maturation and deterioration of their predicted FH (from 162.1 +/- 6. 2 cm to 155.3 +/- 5.6 cm; P <.01), which was at that time significantly lower than their target height (P <.05) (mean target height = 159.8 +/- 4.6 cm). They received a gonadotropin-releasing hormone agonist for 2.1 +/- 0.7 years, resulting in a restoration of growth prognosis (mean FH or near FH = 160.2 +/- 6.7 cm). CONCLUSIONS: This study demonstrates that not all patients with apparent idiopathic precocious puberty require medical treatment, notably when there is no evidence of hypothalamo-pituitary ovarian activation or no significantly advanced BA to impair height potential. Most show a slowly progressing puberty. However, careful follow-up of these patients is necessary up to at least 9 years of age, because until then height prediction may deteriorate, necessitating gonadotropin-releasing hormone agonist treatment in one third of the cases.

Reduced bone mineral density at diagnosis and bone mineral recovery during treatment in children with Graves' disease.

OBJECTIVES: In children with Graves' disease, the prevalence of osteopenia is unknown, and the possible restoration of bone mass by antithyroid treatment has not been evaluated. The aim of this study was to prospectively evaluate the bone mineral density (BMD) and bone metabolism at diagnosis and after 1 and 2 years of medical treatment. Twenty-six children (19 girls and 7 boys) aged 11 +/- 3.4 years (range 3.4 to 15.3 years) were studied. STUDY DESIGN: BMD of the lumbar spine and proximal femur were measured by dual-energy x-ray absorptiometry. Values were compared with those of healthy children of similar age, sex, and pubertal stage. RESULTS: At diagnosis the mean BMD (standard deviation score [SDS]) was significantly reduced in both sites (P <.001) with a preferential loss of cortical bone (femoral BMD = -1.7 +/- 1.0 SDS) rather than trabecular bone (lumbar spine BMD = -0.8 +/- 1.1 SDS) (P =.003). Severe osteopenia (below -2 SDS) was found in 11 (42%) of 26 patients. Osteocalcin was significantly higher than in the control group (P <.0001), but other bone metabolism markers were normal. During treatment (n = 19) a significant gain in femoral (F = 14.7; P =.001) and lumbar spine (F = 5; P =.02) BMD (SDS) was observed, and none of the patients showed osteopenia. The annual percent change in the BMD values at the femoral (+23% +/- 11% and +6% +/- 4%, respectively, during the first and second years) and lumbar spine (+19% +/- 9% and +6% +/- 5%, respectively, during the first and second years) sites was greater during the first year than during the second year of treatment (P <.02 for femoral, P <.04 for lumbar spine). No significant age difference in BMD SD score or in BMD percent change values was observed. Osteocalcin returned rapidly to normal values, and all other bone metabolism markers remained in the normal range. CONCLUSIONS: In conclusion, severe osteopenia was observed at diagnosis in children with Graves' disease but was rapidly corrected after 1 and 2 years of treatment. Initial reduced bone mass with high bone turnover caused by hyperthyroidism was corrected after 1 year of euthyroid conditions.

Nasal pyriform aperture stenosis and absence of the anterior pituitary gland: report of two cases.

We describe two female infants with congenital nasal pyriform aperture stenosis and severe pituitary insufficiency. The anterior pituitary gland was undetectable with magnetic resonance imaging. Consanguinity of parents in both cases suggests autosomal recessive inheritance of this disorder. An early fetal developmental defect may explain this syndrome, which affects midline craniofacial structures. In patients with congenital pyriform aperture stenosis, magnetic resonance imaging of the brain and endocrine investigations should be performed for rapid diagnosis and treatment of the latter to avoid major neurologic complications.

Role of congenital hypothyroidism in hearing loss in children.

No significant difference was found for the auditory thresholds at conversational and high frequencies between 42 children with congenital hypothyroidism treated with L-thyroxine and an age-matched control group, regardless of the cause of the thyroid failure or hormone level and the age at the start of treatment.