Marked Suppression of Ghrelin Concentration by Insulin in Prader-Willi Syndrome

The plasma ghrelin has been reported to be elevated in Prader-Willi syndrome (PWS) and modulated by insulin. It was hypothesized that insulin might have a more pronounced effect on reducing plasma ghrelin in PWS patients, which would influence appetite. This study investigated the degree of ghrelin suppression using an euglycemic hyperinsulinemic clamp in children with PWS (n=6) and normal children (n=6). After a 90-min infusion of insulin, the plasma ghrelin level decreased from a basal value of 0.86+/-0.15 to 0.58+/-0.12 ng/mL in the controls, and from 2.38+/-0.76 to 1.12+/-0.29 ng/mL in children with PWS (p=0.011). The area under the curve below the baseline level over the 90 min insulin infusion was larger in children with PWS than in controls (-92.82+/-44.4 vs. -10.41+/-2.87 ng/mL/90 min) (p=0.011). The insulin sensitivity measured as the glucose infusion rate at steady state was similar in the two groups (p=0.088). The decrease in the ghrelin levels in response to insulin was more pronounced in the children with PWS than in the controls. However, the level of ghrelin was always higher in the children with PWS during the clamp study. This suggests that even though insulin sensitivity to ghrelin is well maintained, an increase in the baseline ghrelin levels is characteristic of PWS.

Clinical and Ultrasonographic Characteristics of Malignant Thyroid Incidentalomas / 대한내분비학회지

BACKGROUND: High-resolution ultrasonography has made the detection of asymptomatic small thyroid possible. Recent increases in the detection of incidentalomas have created a clinical dilemma on how to properly manage such incidental nodules. We investigated the prevalence, clinical and ultrasonographic characteristics, and optimal diagnostic approach toward incidentally detected benign and malignant thyroid nodules of less than 1.5 cm in size. METHODS: A retrospective review was undertaken on the 1,475 patients who had visited Samsung Medical Center, Seoul Korea between January 1999 and December 2000. The review consisted of a physical examination of the thyroid gland, thyroid function test, antithyroid antibodies, thyroid ultrasonography, fine-needle aspiration biopsy, pathology and TNM staging of the incidentally detected thyroid nodules of less than 1.5 cm in size. RESULTS: The prevalence of thyroid incidentalomas was 13.4% and the malignancy rate within them was 28.8%. There were no significant differences in age, sex, thyroid function test and size between the benign and malignant incidentalomas. Ultrasonographic characteristics showed meaningful diagnostic value for the detection of malignancy in incidentalomas. Most malignant incidentalomas were of a low stage. CONCLUSION: Occult thyroid cancers are fairly common finding. There are no clinical difference between benign and malignant thyroid nodules less than 1.5 cm ; however, ultrasonographic fingings can be used to decision of optimal management strategies.