Accuracy of fine needle aspiration biopsy of thyroid nodules in detecting malignancy in childhood: comparison with conventional clinical, laboratory, and imaging approaches.

In childhood the traditional diagnostic approach to thyroid nodules consists of clinical, laboratory, and imaging evaluations. A safe and accurate procedure is needed to promptly identify patients who require surgery. In regard to the usefulness of fine needle aspiration biopsy, the data in the literature concerning children and adolescents are scanty. The aim of this study was to evaluate and compare the diagnostic accuracies of clinical, laboratory, and imaging data collected retrospectively in a group of pediatric patients with thyroid nodules submitted to fine needle aspiration biopsy. Forty-two patients who underwent surgery for thyroid nodules, recruited in 9 Italian pediatric endocrine units, were retrospectively studied. According to histological diagnosis, they were divided into 2 groups, 22 patients with benign lesions and 20 patients with malignant lesions. From clinical records we obtained data about 1) symptoms of neck compression; 2) cervical adenopathy; 3) thyroid function, calcitonin level, and antithyroid antibody titers; 4) ultrasonography; 5) (99m)Tc scintiscanning; and 6) cytology obtained with fine needle aspiration biopsy. Patients and nodule characteristics were analyzed statistically for associations with the presence of thyroid cancer. Among clinical findings, only adenopathy was significantly higher in the group with cancer (8 of 22 benign lesions vs. 16 of 20 malignant lesions; P = 0.006). Thyroid function and antibody titers were similar in the 2 groups, whereas the serum calcitonin level was elevated only in 1 patient with malignant lesions. Among ultrasonography findings, no significant statistical difference was found between the 2 groups with regard to number, dimensions, growth progression, or hypoechogenic pattern of the nodules. Regarding scintigraphic findings, no significant difference was found between the 2 groups. However, a positive correlation (r = 0.90; P < 0.0001) was found between fine needle aspiration biopsy cytological findings and histological diagnoses. The sensitivity, specificity, and accuracy of fine needle aspiration biopsy were 95%, 86.3%, and 90.4%, respectively. A multiple regression analysis showed that only fine needle aspiration biopsy (beta coefficient = 0.963; P < 0.0001) significantly contributed to detecting malignancy (multiple r = 0.973; P < 0.0001). This study provides strong evidence that fine needle aspiration biopsy is a safe technique even in childhood and adolescence, offering the best sensitivity, specificity, and accuracy in detecting malignancy compared with conventional approaches.

IGF-1 and IGFBP-3 in congenital and acquired hypothyroidism after long-term replacement treatment.

BACKGROUND: Thyroid hormones are involved in the regulation of the GH/IGF axis. Hypothyroidism is associated with a reduction in GH pulsatility and in GH-response to stimulatory tests. In hypothyroidism, serum levels of IGF-I and IGFBP-3 fall and these changes are reserved after short-term replacement with L-T4. This study was undertaken to determine the effect of long-term replacement therapy with T4 in IGF-1 and IGFBP-3 serum levels. METHODS: The study included 12 patients affected with hypothyroidism and in replacement treatment with T4. They were divided into 3 groups according to age at the beginning of treatment. Group A consisted of 4 pre-pubertal subjects with Congenital Hypothyroidism (CH) diagnosed with neonatal screening, where T4 treatment was started within 15 days of life. Group B consisted of 5 young adults where CH was clinically diagnosed at the median age of 6 months and replacement therapy started at this age. Group C consisted of 3 subjects affected with hypothyroidism secondary to thyroiditis where diagnosis and replacement treatment were delayed at age 11, 12 and 14 respectively. All subjects were matched with a control of the same age, sex, weight and pubertal stage. RESULTS: FT3, FT4 and TSH were in the normal range both in patients and in controls. No correlation was found between FT3 or FT4 and IGF-1 or IGFBP-3 serum levels. IGF-1 serum levels in group A (198 +/- 122 ng/ml) were significantly lower than that in group B (624 +/- 105, p < 0.001) and in group C (649 +/- 98, p=0.003). IGFBP-3 serum levels in group A (1.98 +/- 0.56 microgram/ml) were significantly lower than in group B (3.65 +/- 1.10, p=0.03) and in group C (4.13 +/- 0.49, p=0.003). The increase of IGF-1 and IGFBP-3 levels was seen also in control groups B and C when compared with control group A. IGF-1 and IGFBP-3 were positively correlated with age both in patients and in controls. A linear correlation was found between IGF-1 and IGFBP-3 which was positive for controls (r=0.946, p < 0.001) and patient group A and B (r=0.839, p = 0.005) but tended to be negative for patient group C (r=0.65, n.s.). CONCLUSIONS: : Our data demonstrate that long-term replacement therapy in children with hypothyroidism is associated with a physiological increase in IGF-1 and IGFBP-3. The positive correlation between IGF-1 and IGFBP-3 levels in group A and B confirm the efficacy of long-term replacement treatment on the IGF-1/BP-3 axis in pre- and post-pubertal patients treated for CH. However, this correlation tended to be negative in patients with hypothyroidism secondary to thyroiditis, suggesting that the cause of thyroid insufficiency and/or the age at the beginning of replacement therapy may have a role in the post-pubertal hormonal status in IGF-1 and IGFBP-3 balance.

IGF-1 and IGFBP in congenital and acquired hypothyroidism after long-term replacement treatment.

BACKGROUND: Thyroid hormones are involved in the regulation of the GH/IGF axis. Hypothyroidism is associated with a reduction in GH pulsatility and in GH-response to stimulatory tests. In hypothyroidism, serum levels of IGF-1 and IGFBP-3 fall and these changes are reversed after short term replacement with L-T4. This study was undertaken to determine the effect of long term replacement therapy with T4 in IGF-1 and IGFBP-3 serum levels. METHODS: The study included 12 patients affected with hypothyroidism and in replacement treatment with T4. They were divided into 3 groups according to age at the beginning of treatment. Group A consisted of 4 pre-pubertal subjects with Congenital Hypothyroidism (CH) diagnosed with neonatal screening, where T4 treatment was started within 15 days of life. Group B consisted of 5 young adults where CH was clinically diagnosed at the median age of 6 months and replacement therapy started at this age. Group C consisted of 3 subjects affected with hypothyroidism secondary to thyroiditis where diagnosis and replacement treatment were delayed at age 11, 12 and 14 respectively. All subjects were matched with a control of the same age, sex, weight and pubertal stage. RESULTS: FT3, FT4 and TSH were in the normal range both in patients and in controls. No correlation was found between FT3 or FT4 and IGF-1 or IGFBP-3 serum levels. IGF-1 serum levels in group A (198 +/- 122 ng/ml) were significantly lower than that in group B (624 +/- 105, p < 0.001) and in group C (649 +/- 98, p = 0.003). IGFBP-3 serum levels in group A (1.98 +/- 0.56 micrograms/ml) were significantly lower than in group B (3.65 +/- 1.10, p = 0.03) and in group C (4.13 +/- 0.49, p = 0.003). The increase in IGF-1 and IGFBP-3 levels was seen also in control groups B and C when compared with control group A. IGF-1 and IGFBP-3 were positively correlated with age both in patients and in controls. A linear correlation was found between IGF-1 and IGFBP-3 which was positive for controls (r = 0.946, p < 0.001) and patient group A and B (r = 0.839, p = 0.005) but tended to be negative for patient group C (r = -0.65, n.s.). CONCLUSIONS: Our data demonstrate that long term replacement therapy in children with hypothyroidism is associated with a physiological increase in IGF-1 and IGFBP-3. The positive correlation between IGF-1 and IGFBP-3 levels in group A and B confirm the efficacy of long term replacement treatment on the IGF-1/BP-3 axis in pre- and post-pubertal patients treated for CH. However, this correlation tended to be negative in patients with hypothyroidism secondary to thyroiditis, suggesting that the cause of thyroid insufficiency and/or the age at the beginning of replacement therapy may have a role in the post-pubertal hormonal status in IGF-1 and IGFBP-3 balance.

Measurement of urinary iodine excretion to reveal iodine excess in neonatal transient hypothyroidism.

This study was undertaken to confirm the importance of iodine excess in neonatal transient hypothyroidism. In 30 transient hypothyroid newborns at screening we measured urinary iodine excretion and TSH. They were divided into two groups: group A consisted of 21 newborns who had been exposed to iodine; group B of 9 non-exposed newborns. The two groups were significantly different only for median urinary iodine excretion (p = 0.001). In 61.5% of newborns of group A, iodine exposure caused iodine excess (urinary iodine excretion higher than 185 micrograms/l); this correlated with a higher prevalence of prematurity and a lower mean gestational age. Clinical records should reveal iodine exposure, but only urinary iodine excretion shows iodine excess. We suggest that evaluation at birth of urinary iodine excretion in every newborn with high TSH could help in predicting a good prognosis, since hypothyroidism due to the Wolff-Chaikoff effect is always spontaneously reversible, even if treatment may be suggested.

The effect of distension of the stomach on plasma renin activity in the anesthetized pig.

It has recently been shown that distension of the stomach in anesthetized pigs causes reflex hemodynamic responses through efferent sympathetic mechanisms. The present study was undertaken to investigate whether these mechanisms include activation of the renin-angiotensin system. In twelve anesthetized pigs, intragastric balloons were distended for periods of 30 minutes by 0.81 of warm Ringer solution (mean gastric transmural pressure of about 12 mmHg). Changes in arterial blood pressure and heart rate were respectively prevented by a pressurized reservoir connected to the left femoral artery and by atrial pacing. Plasma renin activity was measured during the last minute of distension by radioimmunoassay of angiotensin I. In each of the twelve pigs distension of the stomach caused an increase in plasma renin activity. In five pigs, this response was graded with step increments of the distension. The increase in plasma renin activity to gastric distension was abolished by bilateral subdiaphragmatic vagotomy (six pigs) and by bilateral section of the renal nerves (six pigs). The present study showed that innocuous distension of the stomach in the anesthetized pig reflexly increased plasma renin activity. The afferent limb of the reflex was in the vagal nerves and the efferent limb involved renal nerves.

The effects of distension of the stomach and the descending colon on phasic coronary blood flow in the anesthetized pig.

Previous studies in anesthetized animals showed that distension of the stomach or the descending colon primarily caused decreases in mean coronary blood flow. Whether these responses occurred during systole or diastole was not investigated. The present work was planned to study the primary effects of the distension of the two viscera on phasic coronary blood flow in the anesthetized pig. In ten animals, the stomach and the descending colon were distended at constant volume by injecting warm Ringer solution into intravisceral balloons (0.8 and 0.25 l respectively) while preventing changes in heart rate and arterial blood pressure. Distensions of the stomach or the descending colon caused a decrease in mean coronary blood flow in each pig. However, the decrease elicited by gastric distension occurred only during diastole, while the decrease caused by descending colon distension involved both systolic and diastolic coronary blood flows. The same effects on phasic coronary blood flow were observed during experiments in which the decreases in mean coronary blood flow elicited by distension of the stomach or the descending colon were further augmented by adding the distension of the second viscerum. The results indicate that the coronary vasoconstriction caused by gastric distension mainly involves the vessels which supply the subendocardial layers of the myocardium, while that caused by descending colon distension also involves the vessels which supply the subepicardial layers. The vasoconstrictor effect on the subendocardial coronary circulation is enhanced by the combined distension of the two viscera.

Evidence for gene conversion in the generation of extensive polymorphism in the promoter of the growth hormone gene.

The human growth hormone gene (GH-N) is located in a cluster of five highly homologous genes that are coordinately expressed in pituitary (GH-N) and in placental tissues (the chorionic-somatomammotropin-like gene, the GH-variant gene and the two chorionic somatomammotropin genes). Sequence analysis from position -162 to position +100 of the GH-N gene has revealed eight nucleotide polymorphisms with no significant difference in frequency between patients affected by isolated growth hormone deficiency and controls. Remarkably, all these variations are located at positions where the GH-N differs from at least one of the other four homologous genes. The analysis of the twelve GH-N haplotypes originating from the combinations of the eight polymorphisms has revealed that not only single variations, but also nucleotide combinations are identical to those of the other placental genes. These findings suggest that whole stretches of the GH-N gene promoter have been replaced by homologous DNA stretches copied from one of the other four loci by repeated gene-conversion-like events, where the GH-N gene has acted as the recipient and the placental genes as donors of the converted sequences. The presence of a Chi-like element also indicates that the GH-N promoter represents a hot spot of gene conversion. Three of these variations cause, in addition, an amino-acid substitution in the GH-gene-derived transcriptional activator gene whose coding sequence overlaps the GH-N promoter. Thus, a DNA region that serves two distintic functions representing the proximal promoter of a gene and the 5' coding region of another gene displays an unusually high degree of polymorphism that has probably arisen because of gene conversion.

Leptin levels as function of age, gender, auxological and hormonal parameters in 202 healthy neonates at birth and during the first month of life.

Leptin signals to the brain energy stores and balance while integrating neuroendocrine functions. Leptin levels in adults are higher in females than in males, while a gender-related difference in newborns is controversial. To clarify this point, in 202 healthy neonates we measured dynamic changes in leptin levels over the first month of life and looked for correlation between leptin levels and auxological and hormonal parameters. Cord leptin concentration in females was higher (p < 0.001) than in males. IGF-I, IGF-II, insulin, testosterone and 17beta-estradiol levels were similar in both sexes while insulin-like growth factor binding protein 3 (IGF-BP3) levels in females were slightly higher than in males. Leptin levels were positively associated to body weight, gestational age, IGF-BP3 levels, insulin levels and maternal body mass index (BMI) at time of delivery. In a subset of subjects (no. = 65), in comparison with cord levels, serum leptin levels were decreased on the 5th day of life (p < 0.0001) and then increased at 1 month (p < 0.0001). Positive association between leptin and weight was lost on the 5th day of life but present again at 1 month. In conclusion, our findings in a large population of neonates definitely show that leptin levels at birth are functions of gender, body weight and gestational age but not of length, cranial circumference, IGF-I and IGF-II levels. These findings, coupled with weight-independent prompt decrease after birth followed by weight-dependent increase at one month of life, suggest that leptin secretion in neonates as well as in adults mainly signals the nutritional state to the brain.

Haemodynamic effects of the intravenous administration of growth hormone in anaesthetized pigs.

Administration of growth hormone in humans has been reported variably to affect arterial blood pressure and ventricular contractility. The present study was undertaken in anaesthetized pigs to establish whether increases in the blood levels of growth hormone primarily affect haemodynamic variables and to determine the mechanisms involved. In pigs anaesthetized with pentobarbitone sodium, left circumflex or anterior descending coronary blood flow was measured with an electromagnetic flowmeter. In a first group of 23 pigs, growth hormone administration (0.05 IU kg-1 i.v.) increased aortic blood pressure and reduced coronary blood flow when heart rate and aortic blood pressure were held constant. These responses were augmented by graded increases in plasma levels of growth hormone. The mechanisms of the above responses were studied in a second group of 29 pigs and involved beta2-adrenergic receptors since they were abolished by propranolol or butoxamine but not by atropine, phentolamine or atenolol. The present study showed that administration of growth hormone in anaesthetized pigs primarily increased aortic blood pressure and vasoconstricted the coronary circulation. The mechanisms of these responses involved beta2-adrenoceptor effects.