Thyroid gland volumes in premature infants using serial ultrasounds.

BACKGROUND: There is a gap in knowledge about the postnatal growth of thyroid gland in preterm infants. OBJECTIVE: To determine postnatal growth of thyroid gland in preterm infants. METHODS: Thyroid gland volume was calculated in 57 prospectively enrolled preterm infants by measuring serial longitudinal, antero-posterior, and transverse dimensions of thyroid gland with ultrasound. Data were analyzed by using the Wilcoxon and independent t test. RESULTS: There was a significant correlation between thyroid volume (TV) and birthweight (BW) (p = 0.01), and between TV and gestational age (p = 0.02). However, unexpectedly, 12 infants had a decrease in TV between the first and second ultrasounds. Infants with late onset bacterial sepsis had lower TVs on their second ultrasounds than infants without sepsis. CONCLUSIONS: Thyroid ultrasound in preterm infants provides noninvasive and quick approach to determine TV and morphology. TV in preterm infants correlates positively with BW and gestational age. However, postnatal growth of thyroid gland is variable and may seemingly be affected by postnatal factors.

Endocrine abnormalities in Townes-Brocks syndrome.

Townes-Brocks syndrome is a recognizable variable pattern of malformation caused by mutations to the SALL1 gene located on chromosome 16q12.1. Only three known cases of Townes-Brocks syndrome with proven SALL1 gene mutation and concurrent endocrine abnormalities have been previously documented to our knowledge [Kohlhase et al., 1999; Botzenhart et al., 2005; Choi et al., 2010]. We report on two unrelated patients with Townes-Brocks syndrome who share an identical SALL1 mutation (c.3414_3415delAT), who also have endocrine abnormalities. Patient 1 appears to be the first known case of growth hormone deficiency, and Patient 2 extends the number of documented mutation cases with hypothyroidism to four. We suspect endocrine abnormalities, particularly treatable deficiencies, may be an underappreciated component to Townes-Brocks syndrome.

A case report of hyperthyroid-associated thymic hypertrophy in a child, presenting as an anterior mediastinal mass.

We present the case of an 8-year-old boy with an anterior mediastinal mass and signs of hyperthyroidism. The anterior mediastinal mass had radiologic characteristics suggestive of thymic hypertrophy and regressed with antithyroid therapy. Though thymic hypertrophy is a known manifestation of hyperthyroidism, this is the youngest reported case. In selected cases, the diagnosis may be made based on the clinical picture, radiologic appearance, and response to antithyroid therapy without the need of a thymic biopsy or thymectomy.

Similar islet function in islet allotransplant and autotransplant recipients, despite lower islet mass in autotransplants.

BACKGROUND: Despite high initial rates of insulin independence after islet allotransplant for type 1 diabetes, long-term islet function is suboptimal. Possible contributing factors include autoimmune recurrence, alloimmune rejection, or immunosuppressant medication toxicity. In contrast, islet autografts, infused at the time of pancreatectomy for chronic pancreatitis, are not subject to these variables. Islet function was compared in autograft and allograft recipients. METHODS: Eight autograft and eight allograft recipients, insulin independent or requiring minimal insulin, were matched for similar duration posttransplant (mean 2.1±1.2 years). Eleven healthy control subjects were also enrolled. Subjects underwent oral and intravenous glucose tolerance testing and arginine stimulation testing. RESULTS: Age, gender, body mass index, duration posttransplant, and hemoglobin A1c levels were similar between groups. Glucose tolerance was worse in transplant recipients compared with controls. Alloislet recipients received significantly more islet equivalents per kg body weight (IE/kg) than autograft recipients (9958±6229 IE/kg vs. 4589±1232 IE/kg, P=0.03). However, the glycemic response to oral glucose tolerance testing, the acute insulin response to glucose, and the acute insulin response to arginine did not differ significantly between islet allograft and autograft recipients. CONCLUSIONS: Insulin secretion and glucose excursion were similar in allograft and autograft recipients, despite the latter group receiving less than half as many islets. Better preservation of islet mass in the autograft setting is likely related to the lack of autoimmunity, alloimmunity, and immunosuppressive drug toxicity, highlighting the potential for better outcomes in islet allotransplant for type 1 diabetes mellitus with refinements in immunosuppression.

Intrahepatic transplanted islets in humans secrete insulin in a coordinate pulsatile manner directly into the liver.

Intrahepatic islet transplantation is an experimental therapy for type 1 diabetes. In the present studies, we sought to address the following questions: 1) In humans, do intrahepatic transplanted islets reestablish coordinated puslatile insulin secretion? and 2) To what extent is insulin secreted by intrahepatic transplanted islets delivered to the hepatic sinusoids (therefore effectively restoring a portal mode of insulin delivery) versus delivered to the hepatic central vein (therefore effectively providing a systemic form of insulin delivery)? To address the first question, we examined insulin concentration profiles in the overnight fasting state and during a hyperglycemic clamp ( approximately 150 mg/dl) in 10 recipients of islet transplants and 10 control subjects. To address the second question, we measured first-pass hepatic insulin clearance in two recipients of islet autografts after pancreatectomy for pancreatitis versus five control subjects by direct catheterization of the hepatic vein. We report that coordinate pulsatile insulin secretion is reestablished in islet transplant recipients and that glucose-mediated stimulation of insulin secretion is accomplished by amplification of insulin pulse mass. Direct hepatic catheterization studies revealed that intrahepatic islets in humans do deliver insulin directly to the hepatic sinusoid because approximately 80% of the insulin is extracted during first pass. In conclusion, intrahepatic islet transplantation effectively restores the liver to pulsatile insulin delivery.