Potency and Tolerance of Calcitonin Stimulation with High Dose ...

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Subjects and Methods Study sample Table 1 summarizes study sample characteristics. The sample comprised 50 non- smoking, non-pregnant adult volunteers without known chronic or serious acute illness or evident thyroid abnormality after screening described below. Subjects could not take prescription medication other than oral contraceptives (9/25 women). Any pre-study laboratory abnormality (potassium, sodium, calcium, creatinine, liver enzymes) resulted in exclusion. The University of Würzburg Ethics Committee approved the study; all subjects gave written informed consent. Screening for thyroid abnormalities Pre-study, all subjects underwent thyroid ultrasonography with a Sonoline Elegra system (Siemens, Erlangen, Germany) featuring a linear 7.5-MHz transducer. Thyroid volume in mL was calculated using the algorithm, 0.5 x length x width x depth. Additionally, subjects underwent free T3, free T4, and TSH measurement using IMMULITE ® 2000 automated chemiluminescent assays (Siemens Healthcare Diagnostics GmbH, Eschborn, Germany). Thyroperoxidase and thyroglobulin autoantibody titers were determined using enzyme immunoassays (Varelisa, Phadia GmbH, Freiburg, Germany). Basal and Stimulated hCT testing We averaged basal hCT measurements taken in the initial examination and before each stimulation test. After pentagastrin stimulation, there was a wash-out period of at least 6 months before the calcium stimulation described below. Eight subjects (1 man, 7 women) missed that calcium stimulation because they became pregnant (n = 1) or left our region (n = 7). Pentagastrin (Pentagastrin Injection BP, Cambridge Laboratories, Wallsend, UK) was administered as an intravenous injection of 0.5 µg/kg body weight over 10 sec and calcium gluconate (Calcium Braun 10%, Braun Melsungen AG, Melsungen, Germany) as an intravenous injection of 2.5 mg/kg at 10 mL/min. All subjects fasted ≥ 4 hr before stimulation. 4
Serum hCT Assay Blood samples were taken via in-dwelling intravenous cannula immediately before and 2 min, 5 min, and 15 min after the intravenous pentagastrin or calcium injection. Samples were placed in ice-water to prevent hCT degradation and transferred to the in-house laboratory within 30 min of being drawn for centrifugation after clotting was complete. Serum samples were assayed for calcitonin using the IMMULITE ® 2000 Calcitonin automated chemiluminescent system (Siemens Healthcare Diagnostics GmbH, Eschborn, Germany), a solid-phase, enzyme–labeled, two-site immunometric assay. The assay received regulatory approval based on data showing an analytical sensitivity of 2 pg/ml. Subsequent testing by the manufacturer has shown an analytical sensitivity of 0.34 pg/ml and a functional sensitivity of 0.7 pg/ml. Analytical sensitivity is defined as a concentration two standard deviations (SDs) above the mean counts/sec of the zero calibrator, i.e., the 97.5 th percentile. Functional sensitivity is defined as the lowest analyte level with an inter-assay coefficient of variation (CV)
Page 1 and 2: J Clin Endocrin Metab. First publis
Page 3: Introduction Human calcitonin (hCT)
Page 7 and 8: calcium-stimulated hCT levels were
Page 9 and 10: References 1. Hahm JR, Lee MS, Min
Page 11 and 12: Tables Table 1. Subject characteris
Page 13 and 14: Figure Legends Figure 1. Serum calc
Page 15 and 16: Calcitonin (pg/ml) B) Calcium stimu

Potency and Tolerance of Calcitonin Stimulation with High Dose ...

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