Regeneration of the parathyroid glands in experimental hyperthyroidism

By means of morphological, morphometric and radioautographic methods, regeneration of mechanically traumatized parathyroid glands has been studied in 22 euthyroid and 22 hyperthyroid rats on the 1st-20th days after the operation. The thyroid gland is stimulated by daily injection of thyrotropin (1 ME/100 g of body mass). Twelve non-operated animals (6 hyperthyroid and 6 euthyroid rats) serve as control. In the regenerating parathyroid glands of the hyperthyroid animals in comparison with the euthyroid ones, certain increase of proliferative activity is noted in parathyrocytes and in cells of the granular tissue on the 2d-6th days, a more pronounced hypertrophy of epitheliocytes on the 2d-20th days, hyperplasia of their nucleolar apparatus on the 2d-5th days. The experimental hyperthyroidism stimulates manifestation of restorative processes in the regenerating parathyroid glands during development of active inflammatory reaction in them; however, it does not influence the parameters of the organ's structure studied in the nonoperated animals.     

Cryosurgery of parathyroid glands

The effectiveness of cryosurgery in destruction of parathyroid glands in rats was studied by comparison of 4 experimental groups: 1. cryosurgery utilizing 3 patterns of repetitive freezing, 2. excision, 3. sham operation, or 4. no treatment. Evaluation included clinical observation of respirations and voice, serum calcium concentration, and histologic examination of parathyroid tissue. The results indicate that the extent of destruction of parathyroid glands in rats can be controlled by specific cryosurgical techniques without thyroidectomy or risk of permanent injury to the recurrent laryngeal nerves.     

Immunocytochemical localization of parathyroid hormone in rabbit parathyroid glands

Immunocytochemical localization of parathyroid hormone was examined in the rabbit parathyroid gland by means of protein A-gold technique. Protein A-gold particles were observed on the secretory granules and the large secretory granules thought to be storage granules. No protein A-gold particles were observed on cisternae of the endoplasmic reticulum and the Golgi apparatus.     

Biosynthetic activity of parathyroid cells during different function of the parathyroid glands

By means of autoradiograph c and morphometric methods parathyroid glands of 31 rats after single injection of 3H-leucin (2,5 mc Cu/g of body mass 25 min. before killing) were investigated. Parathyroid glands were inhibited by multiple injections of calcium gluconate solution or by a diet with increased content of calcium and vitamin D2. Parathyroids were stimulated by multiple injections of Trilon B solution, by a diet with increased content of phosphates or by subtotal parathyroid resection. Straight correlation between parathyroid function, average section area of parathyrocytes and average number of silver granules per one parathyrocyte was revealed. Hence, average section area of parathyrocytes is objective morphometric criterion of parathyroid function.     

The thyroid and parathyroid glands in the Rhinocerotidae

As a contribution to rhinoceros splanchnology obsevations are submitted upon the gross and microscopical anatomy of the rhinoceros thyroid and parathyroid glands, following a particular examination of these organs in examples of the genera Rhinoceros, Didermocerus, Ceratotherium and Diceros .     

Morphological identification of the lipid-storing cells in golden hamster parathyroid glands after vitamin A treatment

We investigated hamster parathyroid glands of different ages using electron microscopy and found a new cell type in young, adult and senile hamsters. Theses special cells were located in interstitial tissues and invariably contained several lipid droplets within the cytoplasm. The cells showed an elongated spindle with some cell processes. The cells contained small Golgi complexes and moderate cisternae of the granular endoplasmic reticulum. The morphological characteristics of these cells were mostly the same as those of lipid-storing cells in other organs (Yamada and Hirosawa, 1976). After vitamin A administration, the lipid droplets in these cells markedly increased in number and also in volume density. The other morphological features of these cells resembled those of the control animals. We called these cells parathyroid lipid-storing cells. They may incorporate and store vitamin A within the lipid droplets. They can be classified as one of the cellular components in hamster parathyroid gland.     

Immunoperoxidase confirmation of parathyroid origin of ultrasound-guided fine needle aspirates of the parathyroid glands

It may be difficult to differentiate between cells of parathyroid and thyroid origin in ultrasound-guided fine needle aspirations of the neck region, even in patients with a clinical history of hyperparathyroidism. A parathyroid hormone antibody was used in an immunohistochemical system to confirm a parathyroid origin in fine needle aspirate smears from nine patients with hyperparathyroidism. Immunoperoxidase positivity for parathyroid hormone confirmed a parathyroid origin in six of nine cases and was strongly suggestive, although equivocal, in the remaining three cases. Technical problems included nonuniform staining and background staining.