Source Of Parathyroid Hormone Research Articles

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Case Presentation: A 40-year-old woman with primary hyperparathyroidism (pHPT) and unlocalized disease (negative neck ultrasonography and sestamibi scan) underwent neck exploration. Two borderline appearing inferior parathyroid glands were removed and a normal right superior gland was left in situ while the left superior gland was not identified. The removed parathyroid glands were of increased weight and histologically showed borderline hyperplasia. However, the postoperative calcium remained raised at over 3.0 mmol/L (2.2 to 2.6 mmol/L). A subsequent, 4-dimensional (4D) computed tomography (CT) scan failed to identify the parathyroid adenoma. Parathyroid angiography and venous sampling demonstrated no vascular blush, but significant elevation of parathyroid hormone (PTH) within the veins draining the left side of the neck. Extensive re-exploration of the left neck failed to identify a parathyroid gland and no drop in intraoperative PTH occurred after a left hemithyroidectomy. Repeated venous sampling was consistent with the source of PTH being within the left superior neck. Fluorine F 18-fluorocholine (FCH)-positive emission tomography (PET)/CT was undertaken and showed intense tracer uptake in a soft tissue focus (6 × 11 mm) lying within the carotid sheath just lateral to the proximal left internal carotid artery and medial to the internal jugular vein (Fig. 1). What is the diagnosis?

Aspects of Calcium Regulation in Embryonic Lepidosaurians and Chelonians and a Review of Calcium Regulation in Embryonic Archosaurians

Embryos of oviparous and viviparous lepidosaurians, chelonians, and archosaurians must maintain calcium homeostasis while mobilizing large quantities of calcium from the yolk, eggshell, or maternal circulation. The same calcium-regulating hormones that control the calcium status of adults are assumed to control the calcium status of embryos as well, but the target organs for calcium regulation may be different in embryos and adults. The yolk sac, which mediates the uptake of calcium from the yolk (and the deposition of calcium into yolk in archosaurians), the chorioallantois, which mediates the release of calcium from the eggshell and the transport of shell calcium to the vasculature in oviparous species, and the chorioallantoic placenta, which mediates the maternal-fetal transfer of calcium in viviparous species, are potential targets for calcium-regulating hormones (calcitonin, parathyroid hormone, calcitriol) during embryogenesis. However, the role of these hormones in mediating the calcium status of embryos has been examined only in avian species, and the most detailed information available in this regard is for calcitriol (the vitamin D hormone). The presence of receptors for calcitriol in the yolk sac and chorioallantoic membranes of avian species and the extreme calcium deficiency of vitamin-D-deficient embryos indicate that calcitriol plays an important role in regulating calcium metabolism during avian embryogenesis. A source of parathyroid hormone also is required for normal development, but the target organ(s)for this hormone have not been identified. The role of calcitonin in calcium regulation by embryonic birds is poorly understood, and the potential for hormonal control of calcium homeostasis in embryonic reptiles has not been examined.

Parathyroid transplantation.

AbstractThis is a review of our current experience with the technique of parathyroid transplantation in man. We have performed 68 autografts and 2 allografts. The indications for parathyroid autotransplantation include primary and secondary parathyroid hyperplasia, repeat neck exploration for persistent or recurrent hyperparathyroidism, and total thyroidectomy for carcinoma. Indications for allotransplantation include the unsuccessful medical management of hypoparathyroidism and complete DiGeorge's syndrome. Graft function was successful in a high percentage of cases as documented by a normal serum calcium concentration with the grafted parathyroid tissue as the only source of parathyroid hormone, by detecting high concentrations of PTH in the antecubital vein draining the grafted arm and, histologically, by light and electron microscopy of the grafts.