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PubMed1989

Calcium-binding proteins in the parathyroid gland. Detailed studies of parathyroid secretory protein.

In order to identify calcium (Ca2+)-binding proteins in the parathyroid gland, we used electrophoretic blots of proteins separated by a two-dimensional nondenaturing/denaturing gel system and incubated them with 45Ca2+. Parathyroid secretory protein (PSP) and proteins with approximate molecular weights of 98,000, 88,000, 58,000, and 30,000 were noted to bind Ca2+ in cytosolic fractions from bovine parathyroid, adrenal, and pituitary glands. However, differences in the binding affinity and capacity of the various proteins were observed. PSP displayed a low affinity and high binding capacity for Ca2+. In the presence of 5 mM MgCl2 and 60 mM KCl, native PSP (immobilized on nitrocellulose filters) bound 7.5 mol of Ca2+/mol of protein monomer with an apparent Kd of 1.1 mM. Immunoblotting identified the association of PSP with parathyroid cell membranes in a Ca2+-dependent manner. This property, together with its heat stability, distinguished PSP from other cytosolic Ca2+-binding proteins which were identified. There was also evidence for a Ca2+-dependent protein-protein interaction (aggregation) of PSP present in a Nonidet P-40 extract of cell membranes. The high Ca2+ binding capacity of PSP and its Ca2+-dependent membrane association may be features that make PSP a potentially important protein in secretory cells.

Adrenal Glands↗
PubMed2006

Ultrasound guided fine needle aspiration biopsy of parathyroid gland and lesions.

BACKGROUND: Parathyroid gland and their tumors comprise a small proportion of non-palpable neck masses that are investigated by ultrasound (US) guided fine needle aspiration biopsy. We reviewed our institution's cases of US guided FNAB of parathyroid gland and their lesions to determine the role of cytology for the preoperative diagnosis of parathyroid gland and their lesions. METHOD: All cases of FNAB of parathyroid gland and lesions in the last 10 years were reviewed in detail with respect to clinical history and correlated with the histopathologic findings in available cases. The cytologic parameters that were evaluated included cellularity assessed semiquantitatively as scant, intermediate or abundant (<50, 51-500 or >500 cells), cellular distribution (loose clusters, single cells/naked nuclei, rounded clusters, two- and three-dimensional clusters, and presence of prominent vascular proliferation), cellular characteristics (cell size, nuclear shape, presence/absence of a nucleolus, degree of mitosis, amount of cytoplasm, and appearance of nuclear chromatin), and background (colloid-like material and macrophages). Immunostaining for parathyroid hormone (PTH) was performed on selected cases using either destained Pap smears or cell block sections. RESULTS: Twenty cases of US-guided FNAB of parathyroid glands and their lesions including 13 in the expected locations in the neck, 3 in intrathyroid region, 3 in thyroid bed, and 1 metastatic to liver were studied. Majority of the cases showed intermediate cellularity (51-500 cells) with round to oval cells that exhibited a stippled nuclear chromatin, without significant pleomorphism or mitotic activity. The cells were arranged in loose two dimensional groups with many single cells/naked nuclei around the groups. Occasionally macrophages and colloid like material was also encountered. There was no significant difference in the cytomorphologic features between normal gland, hyperplasia adenoma, or carcinoma. Immunocytochemical analysis for PHT was performed for 14 cases (6 destained smears and 8 cell blocks) which showed distinct cytoplasmic positivity. CONCLUSION: US-guided FNAB is a useful test for confirming the diagnosis of not only clinically suspected parathyroid gland and lesions but also for detecting parathyroid glands in unexpected locations such as in thyroid bed or within the thyroid gland. Although there is significant overlap in the cytomorphologic features of cells derived from parathyroid and thyroid gland, the presence of stippled nuclear chromatin, prominent vascular proliferation with attached epithelial cells, and frequent occurrence of single cells/naked nuclei are useful clues that favor parathyroid origin. Distinction of the different parathyroid lesions including hyperplasia, adenoma, and carcinoma cannot be made solely on cytology. Immunostaining for PTH can be performed on destained Pap smears and cell block sections which can be valuable for confirming parathyroid origin of the cells.

Journal Article↗
PubMed1992

Estimated weight of the residual parathyroid gland after parathyroidectomy using plasma levels of the parathyroid hormone.

The possibility of estimating the total weight of the parathyroid glands based on the plasma concentration of the parathyroid hormone (PTH) would be of great help when searching for the parathyroid glands during surgery on patients with secondary hyperparathyroidism. Thus, we studied the relationship between the levels of carboxyl-terminal PTH (C-PTH), midportion PTH (M-PTH) and intact PTH, and the weight of the parathyroid glands resected for secondary hyperparathyroidism. The subjects studied were 11 patients with secondary hyperparathyroidism caused by chronic renal failure. The pre- and post-operative differences in the plasma C-PTH levels and plasma M-PTH levels were significantly correlated with the weight of the resected parathyroid glands (p less than 0.001 for both), but there was no correlation between the differences in the levels of intact PTH and the weight of the resected parathyroid glands. From these relationships we estimated the weight of the residual parathyroid gland after parathyroidectomy using the levels of each PTH. All patients in whom the residual parathyroid gland was estimated to be heavy based on the levels of M-PTH showed recurrence of hyperparathyroidism after the parathyroidectomy. We therefore found that estimation of the weight of the parathyroid glands from the levels of M-PTH is both possible and useful.

Adult↗
PubMed1985

[Spatial organization of proliferative processes in the parathyroid glands upon acute stimulation of parathyroid function].

A quantitative analysis on homogeneity degree in distribution of proliferating parathyrocytes in the parathyroid glands under conditions of an acute stimulation of their function, produced by bilateral nephrectomy (12 rats, 50-70 h after the operation) and by hemiparathyroidectomy (12 rats, 2-3 days after the operation) have been performed. Six intact animals serve as the control. In order to reveal proliferating cells, 1 h before sacrifice 3H-thymidine (1 mc Ci/g) is injected intraperitoneally, and to some animals--colchicine (1 mg/kg) is injected 6 h before the sacrifice. By means of successive investigation of the glands serial sections along their whole area the amount of the microscope field of vision, having various content of proliferating cells are calculated; using the criterion chi 2, the correspondence of the empiric distributions obtained to the Poisson distribution are estimated. In the hyperfunctioning parathyroid glands the proliferating cells form foci of clusters and rarifaction. A similar clustering appears when a definite level of mitotic activity of the parathyrocytes is reached (1-1.2%), probably reflecting certain regional peculiarities of their functional state.

Animals↗
PubMed1989

Autotransplantation of avian parathyroid glands: an animal model for studying parathyroid function.

The parathyroid glands of chickens were autotransplanted and the return of parathyroid function following transplantation was determined. Parathyroidectomy (PTX) resulted in a marked hypocalcemia (5.2 +/- 0.2 mg/dl) 4 hr following PTX. Plasma calcium (PCa) had declined to 4.3 +/- 0.2 mg/dl 24 hr after PTX. Parathyroid glands were transplanted subcutaneously 24 hr after removal and 24 hr later, PCa had risen to 8.6 +/- 0.5 mg/dl. Seven days after PTX. PCa increased to 10.3 +/- 0.2 mg/dl and by 14 days was indistinguishable from control levels (10.8 +/- 0.2 mg/dl vs. 11.0 +/- 0.2 mg/dl, respectively). When chicks with transplanted glands were fed a low Ca (0.08%) diet for 2 weeks they were able to maintain plasma PCa at levels comparable to control birds. Removal of the transplanted glands resulted in marked decreases in PCa (from 9.7 +/- 0.3 to 5.6 +/- 0.8 mg/dl), in the fractional excretion of phosphate, in urine cAMP, and in renal 25OH-vitamin D3-1 alpha-hydroxylase activity. Stepwise reductions in PCa and 1 alpha-hydroxylase activity were produced in partially PTX and fully PTX chicks by removing part or all of the parathyroid tissue. These data suggest that the transplanted parathyroid tissue was the major source of circulating PTH and that it may be possible to produce different degrees of acute hypoparathyroidism by varying the amount of transplanted parathyroid tissue removed surgically. Chickens with transplanted parathyroid glands thus provide a convenient animal model in which to study parathyroid function in an avian species.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1989

[Reappraisal of T1-Tc scanning in the preoperative localization of hyperfunctioning parathyroid glands].

Preoperative localization for hyperfunctioning parathyroid glands remains a problem in clinical parathyroid surgery. From January 1984 to August 1986, a total of 16 patients with the diagnosis of primary hyperparathyroidism (14) or secondary hyperparathyroidism (2) received preoperative T1-Tc image studies to localize the hyperfunctioning parathyroid glands. All the patients underwent surgery as soon as the diagnoses had been confirmed, and were cured. During surgery, bilateral neck explorations and parathyroid biopsies were routinely performed. All the adenomas were removed, and half of the hyperplastic parathyroid gland was preserved in patients with 4 enlarged hyperplastic glands (3 1/2 hyperplastic glands were removed). The results of the T1-Tc scans correlated with the pathological and operative findings. A hyperfunctioning parathyroid gland with a positive scan was considered as a true positive; a hyperfunctioning parathyroid gland with a negative scan was considered a false negative; normal parathyroid glands with negative scans were considered true negatives; while positive scans without hyperfunctioning parathyroids were counted as false positives. The sensitivity, specificity and accuracy of this localization tool were thereby calculated. On at least 6 months of follow-up, all the patients remained normocalcemic. T1-Tc scanning showed a total of 20 positive images: 6 images were proved to be enlarged parathyroid adenomas, 13 images to be hyperplastic glands and the other one to be thyroid nodule. Also, 2 adenomas, 19 hyperplastic glands and 22 normal parathyroid glands not visualized by T1-Tc scanning were found on exploration. Eight of the 14 patients with primary hyperparathyroidism included 1 adenoma in each patient, 3 normal glands in 6 patients and 2 normal glands in the other 2 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1988

Establishment of primary cell cultures from human and canine parathyroid gland explants.

Primary parathyroid cell cultures were established from 22 canine and 20 human parathyroid glands explanted into Connaught Medical Research Laboratory-1415 (CMRL-1415) medium containing fetal calf serum (FCS). Initiation of cellular outgrowth and the rate of cellular propagation through the first subcultures were evaluated in various media. These included Roswell Park Memorial Institute-1640 (RPMI-1640), minimal essential medium (MEM), medium-199 (M-199) and Coon's modified Ham's F-12 (F12) and CMRL-1415 media. Only CMRL-1415 medium supplemented with FCS invariably supported the vigorous rate of cellular growth as determined by the number of cells in cultures, their viability, parathyroid hormone (PTH) levels in the growth media and the number of proliferating cells. Propagation of parathyroid cells in vitro was limited to five passages. Cessation of cell division was always coincidental with the emergence of numerous, non-dividing binucleated cells. These experiments demonstrate that primary parathyroid cell cultures from canine and human parathyroid gland explants can be readily established in CMRL-1415 medium containing FCS.

Animals↗
PubMed1986

Methylene blue infusion for intraoperative identification of the parathyroid glands.

Identifying the parathyroid glands is of fundamental importance in thyroid and parathyroid surgery. We found that intravenous infusion of methylene blue was beneficial in intraoperative identification of the parathyroid glands in patients undergoing surgery for hyperparathyroidism as well as total and bilateral subtotal thyroidectomy. The technique is safe and easy to use, and it clearly reduces the operative time. We suggest that it be used routinely in thyroid and parathyroid surgery.

Adult↗
PubMed1992

Thallium-technetium subtraction scintigraphy of enlarged parathyroid glands after calcitonin stimulation of parathyroid hormone secretion.

To improve the sensitivity of thallium-technetium subtraction scintigraphy for preoperative localization procedure of enlarged parathyroid glands in primary hyperparathyroidism, we administered calcitonin intramuscularly 4 hours before the scintigraphy in 14 consecutive patients. Injection of calcitonin reduced plasma levels of ionized calcium from 1.47 +/- 0.10 mmol/l to 1.41 +/- 0.09 mmol/l (p less than 0.01). Concomitantly, serum levels of intact parathyroid hormone increased from 6.4 +/- 2.5 pmol/l to 7.9 +/- 2.6 pmol/l (p less than 0.001). The scintigram after calcitonin injection visualized 11 adenomas (sensitivity 78%) compared to only 9 (sensitivity 64%) in conventional scintigrams. In addition, 5 of the adenomas were more distinctly imaged in the scintigram after calcitonin injection, whereas in only one patient was the conventional scintigram better. Thus, the calcitonin injection improved the scintigram in 7 cases and was inferior in only one case (p = 0.031). We conclude that stimulation of parathyroid hormone secretion with calcitonin results in a better preoperative localization of enlarged parathyroid glands in primary hyperparathyroidism.

Adenoma↗
PubMed1995

[Diagnosis of dysfunctions of replanted parathyroid gland tissue by bilateral analysis of intact parathyroid hormones in cubital vein blood. A prospective study].

AIM: In a prospective long-term follow-up study after operative therapy of hyperparathyroidism the value of bilateral determination of parathyroid hormone levels in cubital venous blood after total parathyroidectomy/autologous parathyroid gland reimplantation (musculus brachioradialis) for diagnosis of dysfunctioning grafted tissue is evaluated. PATIENTS AND MATERIAL: From August, 1, 1987 to March, 31, 1994 68 of 243 patients operated on for hyperparathyroidism underwent total parathyroidectomy. Autologous reimplantation of parathyroid gland was carried out simultaneously in 64 patients. Twice delayed reimplantation of cryopreserved tissue was carried out, and there was no reimplantation in two patients up to this day. Three patients were operated on for hyperfunctioning parathyroid autograft after former total parathyroidectomy/reimplantation. RESULTS: During follow-up 5 patients developed dysfunction of (reimplanted) parathyroid gland. Because of low or unprovable levels of intact parathormone the gradients of intact parathyroid hormone between grafted and nongrafted forearm were about 1:1 in postoperative hypoparathyroidism as well as in hypofunction of parathyroid gland. After successful replantation of cryopreserved parathyroid tissue gradients of intact parathyroid hormone increased (> 1:10). In hyperfunction of grafted parathyroid tissue hormone gradients were high (> 1:20 to 1:45,3) because of excessive high levels of intact parathormone in the cubital vein of the graft bearing arm. Successful reduction of parathyroid graft was followed by decrease of parathyroid hormone gradients. CONCLUSION: Regular follow-up of intact parathormone gradients together with intact parathyroid hormone levels and serumcalcium analysis allow the determination of parathyroid graft function. Also differentiation between graft dependent hyperparathyroidism and hyperfunctioning parathyroid tissue in the neck or mediastinum seems to be possible by bilateral determination of intact parathormone. Normal values or a normal range for intact parathyroid hormone gradients can not yet be defined.

Adult↗
PubMed2004

Kinetics of intraoperative fluorescence diagnosis of parathyroid glands.

OBJECTIVE: Identification of parathyroid glands is often a challenge even for experienced surgeons. The feasibility and efficacy of fluorescence diagnosis for localization of parathyroids has already been proven in an experimental setting. In preparation for a clinical application of this technique in patients undergoing surgery for hyperparathyroidism, we evaluated the kinetics of fluorescence diagnosis. DESIGN AND METHODS: Fifty rats were randomized into eight groups with different photosensitization parameters using the photosensitizer aminolevulinic acid (ALA): a peritoneal lavage was performed with either 1.5 or 3.0% ALA solution and the induced photosensitization times varied from 0.5, 1 and 2 to 4 h. Under special fluorescence illumination, D-light, the exposed operative site with thyroid, parathyroid glands and neck muscles was examined. The identified parathyroid glands were studied according to fluorescence intensity by spectrometric measurement and compared with surrounding tissue. RESULTS: Photosensitizer accumulation in parathyroid glands, indirectly measured by spectrometry, was up to 3.2 times higher than in thyroid and 2.6 times higher than in muscle tissue (2 h photosensitization with 3.0% ALA). Using 1.5% ALA, the optimum fluorescence intensity and ratio/contrast was slightly lower (parathyroid-to-thyroid ratio x 3.0, parathyroid-to-muscle ratio x 1.9) but was reached earlier (1 h) and hence considered as the parameter of choice for a clinical application. CONCLUSIONS: In future clinical application, intraoperative fluorescence diagnosis is expected to increase the ease of identification of atypically located or supernumeric glands. In combination with preoperative diagnostics, this may result in reduced operation time and avoidance of persistent hypercalcaemia.

Aminolevulinic Acid↗