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Background: We sought to better understand the experience of patients with transient hypoparathyroidism using patient interviews and quality of life surveys., Methods: This is a prospective analysis of 62 patients after total thyroidectomy at a high-volume institution. Semistructured patient interviews and quality of life surveys were conducted preoperatively and postoperatively at 2 weeks, 6 weeks, 6 months, and 1 year and compared based on postoperative parathyroid hormone levels., Results: Postoperative parathyroid hormone levels were <10 pg/mL in 32% of patients (n = 20), 10 to 20 pg/mL in 19% (n = 12), and >20 pg/mL in 48% (n = 30). Hypocalcemic symptoms at 2 weeks were reported in 28 of 55 patients (51%), but patients felt "well prepared" and reported it "wasn't a big deal." If symptoms persisted at 6 weeks, they became more bothersome. At 6 months and 1 year, patients reported calcium supplementation prevented most symptoms and did not interfere with daily activities. Quality of life as measured by the European Organization for Research and Treatment of Cancer and the 12-Item Short Form Survey demonstrated a slight improvement at 1 year postoperatively regardless of parathyroid hormone level., Conclusion: Early postoperative transient hypoparathyroidism is common but when appropriately managed did not have a substantial negative impact on the overall quality of life., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Parathyroidectomy (PTx) decreases the mortality rate of refractory secondary hyperparathyroidism (rSHP) due to chronic kidney disease. A consensus regarding which techniques of PTx are associated with better outcomes is not available. The aims of this study are to evaluate the clinical and laboratory evolution of 49 hemodialysis patients with rSHP who underwent PTx using different techniques., Methods: Patients underwent subtotal PTx (sub-PTx) or total PTx with autotransplantation (AT) of 45 (PTx-AT 45 ) or 90 parathyroid fragments (PTx-AT 90 ) and were followed for 12 months. We analyzed the expression of proliferating cell nuclear antigen (PCNA), calcium-sensing receptor (CasR), vitamin D receptor (VDR), fibroblast growth factor receptor-1 (FGFR1), sodium-dependent phosphate cotransporter-1 (PIT1), and Klotho in parathyroid glands., Results: Baseline median serum intact parathyroid hormone (iPTH) levels were 1,466 (1,087-2,125) pg/mL; vascular calcification scores correlated with serum iPTH (r = 0.529; P = .002) and serum phosphate levels (r = 0.389; P = .028); and Klotho expression was negatively correlated with serum phosphate levels (r = -0.4; P = .01). After 12 months, serum iPTH and alkaline phosphatase levels were significantly controlled in all groups, as was bone pain. The proportions of patients with serum iPTH levels within the ranges recommended by Kidney Disease: Improving Global Outcomes were similar among the treatment groups. During the hungry bone disease (HBS), patients received 3,786 g (1,412-7,580) of elemental calcium, and a trend toward a positive correlation between the cumulative calcium load at the end of follow up and VC score post-PTx was noted (r = 0.390; P = .06). Two cases evolved to clinically uncontrolled hyperparathyroidism in the sub-PTx group. The expression patterns of PCNA, VDR, CasR, PIT1, FGFR1, and Klotho in parathyroid glands did not correlate with serum systemic iPTH levels or the duration of HBS., Conclusions: All 3 operative techniques were effective at controlling rSHP, both in clinical and laboratory terms. Neither the quantity nor quality of parathyroid fragments influenced serum systemic iPTH and AT-iPTH levels. The cumulative calcium load appeared to correlate with the VC score and may have affected its progression. The effects of phosphate restriction on Klotho expression in human parathyroid glands and the subsequent decrease in FGF23 resistance must be addressed in further studies., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Calcium-sensing receptor (CaSR) is expressed by parathyroid cells and thyroid C-cells (from which medullary thyroid carcinoma [MTC] is derived). A molecular imaging agent localizing to the CaSR could improve the detection of parathyroids and MTC preoperatively or intraoperatively. We synthesized a novel compound containing a fluorine residue for potential future labeling and demonstrated that the compound inhibited CaSR function in vitro., Methods: We synthesized compound M, a derivative of a known calcilytic compound, Calhex-231. Human embryonic kidney cells transfected with green-fluorescent protein-tagged CaSR or control vector were preincubated with compound M before the addition of calcium. Immunoblotting for total mitogen-activated protein kinase (MAPK: ERK1/2), activated MAPK (phosphorylated ERK1/2), and glyceraldehyde 3-phosphate dehydrogenase was performed., Results: Synthesis of compound M was confirmed by mass spectrometry. Inhibition of the MAPK signaling pathway by compound M was demonstrated in a dose-dependent manner by a decrease in phosphorylated ERK1/2 with no change in total ERK1/2 levels. Compound M inhibited MAPK signaling slightly better than the parent compound., Conclusion: We have developed a novel molecule which demonstrates functional inhibition of CaSR and has a favorable structure for labeling. This compound appears to be appropriate for further development as a molecular imaging tool to enhance the surgical treatment of parathyroid disease and MTC., (Copyright © 2013 Mosby, Inc. All rights reserved.)

Background: Human pituitary adenomas express folate receptors (FR); therefore, we hypothesized that parathyroid (PT) tumors also might express FR, whereas normal human thyroids might not. The purpose of our study was to characterize the functionality of FRs on human PT tumors, with the goal of developing an imaging tool that would concentrate in PT more than in the thyroid., Methods: Human PTs and thyroids were evaluated for FR expression by immunohistochemistry. Expression of genes for FRα and FRβ was measured with the Illumina Human HT-12 Expression Bead Chips and verified by quantitative reverse-transcription polymerase chain reaction. Folate incorporation by PT cells versus normal thyroid cells was determined by incubation with (99m)Technetium ((99m)Tc)(CO)3-folate and (99m)Tc-Etarfolatide, and uptake was determined by gamma counting. Specific targeting of FRs was demonstrated by blocking with cold folate. A549 cells and Jurkat cells served as FR-negative controls, and KB cells and HeLa cells were FR-positive controls., Results: On immunohistochemistry and Western blotting, human PT cells expressed FRs, whereas human thyroid cells did not. The FRα gene was expressed in all PTs analyzed, and the FRβ gene was expressed by most. Uptake of (99m)Tc(CO)3-folate was increased in PT cells versus thyroid cells. There was dose-dependent uptake of (99m)Tc-etarfolatide, and uptake was inhibited by preincubation with cold folate, confirming FR-mediated binding., Conclusion: This is the first report of the expression and functionality of FRs on human PT cells. These findings suggest that (99m)Tc-folate holds potential for localization of PT tumors preoperatively and their treatment., (Copyright © 2013 Mosby, Inc. All rights reserved.)

Background: Parathyroid histopathology has been used to predict single or multiglandular disease (MGD). "Hyperplasia" implies MGD, whereas "adenoma" suggests single gland involvement. Intraoperative parathyroid hormone (PTH) monitoring (IPM) guides parathyroidectomy based on function. We sought to evaluate the accuracy of histopathology in the diagnosis of single or MGD and in predicting operative success., Methods: We reexamined the parathyroid glands from 402 patients with sporadic primary hyperparathyroidism (SPHPT) who underwent initial IPM-guided parathyroidectomies. Operative findings and outcome were correlated with histopathology of excised glands. Operative success was eucalcemia for >or=6 months and recurrence of hypercalcemia/high PTH after successful parathyroidectomy., Results: Of 402 patients, 384 had 1 gland excised resulting in operative success; hyperplasia was diagnosed in 244 of the 384 (64%), with only 2 developing recurrence. Of the 384 patients, 140 (37%) had adenomas with 1 late recurrence. There were 18 patients with MGD (14 hyperplasias, 4 adenomas). There were 5 failures with hyperplasia predicting MGD. Histopathology was incorrect in predicting the number of glands involved in 249 of 402 (62%) patients, and IPM was incorrect in only 13 (3%)., Conclusion: Histopathology of excised abnormal parathyroid glands does not predict the secretory function of the remaining parathyroid glands left in situ. IPM guided parathyroidectomy accurately based on function alone; however, histopathology was inaccurate in predicting MGD and should not be used to guide parathyroidectomy in patients with SPHPT.

Background: Parathyroid hormone (PTH) monitoring with a quick intact PTH (QIPTH) assay is used in minimally invasive exploration for primary hyperparathyroidism (PHPT) in order not to miss multiple gland disease (MGD). Controversy exists on which criterion is most reliable to predict cure., Methods: QIPTH values of 310 consecutive patients (single gland disease [SGD]: n = 289; MGD: n = 21) with sporadic PHPT were analyzed using 3 different criteria: "Vienna Criterion": >/=50% decay from a defined "baseline" level (right after induction of anesthesia before skin incision) 10 min after excision. "Miami Criterion": >/=50% decay from highest (preincision or preexcision) value 10 min after excision; "Halle Criterion": decay of the PTH- level to less than or equal to 35 pg/mL within 15 min after excision., Results: The "Vienna" and "Halle Criteria" correctly detected MGD in 19 (91%) and the "Miami Criterion" in 12 (57%) of 21 patients. Incorrect prediction of incomplete excision occurred in 22 patients (8%) with SGD, using the "Vienna Criterion" ("Miami Criterion": 2%, "Halle Criterion": 29%). All of these were recognized intraoperatively from unintended intraoperative manipulation (n = 18), technical failure (n = 2), or borderline increased PTH values (n = 2), and they did not lead to bilateral exploration. Analyzing patients with SGD and MGD, accuracy and specificity were 92% and 89% for the "Vienna Criterion," 93% and 54% applying the "Miami Criterion," and 72% and 89% using the "Halle Criterion.", Conclusion: Strict definition of a PTH "baseline level" ("Vienna Criterion") improves intraoperative diagnosis of MGD, thus reducing reoperations and increasing long-term cure.

Background: Localization of hyperfunctioning parathyroid glands in patients with previous cervical operations is not always successful with noninvasive methods such as ultrasound, sestamibi scan, or magnetic resonance imaging. The aim of our study was to evaluate the results of selective venous sampling (SVS) of intact parathyroid hormone (PTH) in patients undergoing surgery for primary (75%) or secondary (25%) hyperparathyroidism (HPT)., Methods: Between January 2000 and January 2006, SVS for PTH was performed in 51 consecutive patients with persistent or recurrent HPT or patients with previous cervical explorations. The results of SVS were compared with those of noninvasive localization studies., Results: Successful surgical treatment was achieved in 47 of 51 patients (92%). SVS had a sensitivity of 83.3% for the correct localization of a parathyroid adenoma (79.5%) or hyperplastic parathyroid glands (91.6%). False-positive or indeterminate results of SVS were found in 6% and 2%, respectively, of the patients. Ultrasound detected enlarged parathyroid glands with a sensitivity of 33.3%, and sestamibi scan with a sensitivity of 57.1%., Conclusions: Compared with noninvasive localization studies, SVS for PTH yielded the best results for recurrent or persistent HPT and for patients with previous neck explorations. SVS is strongly recommended in reoperative surgery for HPT with indeterminate results of noninvasive methods.

Background: With minimally invasive parathyroidectomy (MIP) not all enlarged parathyroid glands are necessarily removed, and intraoperative measurement of parathyroid hormone levels (IO-PTH) does not necessarily predict multiple enlarged glands. The aim of this study was to compare morphology with function, using Ca(2+)-regulated PTH secretion., Methods: PTH secretion was determined by perifusion: (1) cells from 12 normal parathyroids were compared with 14 parathyroid adenomas; (2) functional characteristics (PTH secretion, sestamibi uptake, IO-PTH decrease) were correlated with morphologic characteristics; (3) PTH secretion as a predictor of IO-PTH decrease was determined in 7 patients with 2 enlarged parathyroids., Results: (1) There were significant differences between normal and pathological parathyroid cells consistent with reduced sensitivity to Ca(2+). Maximum secretion rates for normal and adenomatous cells were, respectively, 3.9 +/- 0.4 fg min(-1) cell(-1) and 2.0 +/- 0.4 fg min(-1) cell(-1) (P = .002) and minimum secretion rates, 0.7 +/- 0.1 fg min(-1) cell(-1) and 0.4 +/- 0.1 fg min(-1) cell(-1) (P = .008). However, the IC(50) value for Ca(2+) was elevated in adenomatous cells indicating an apparent loss of extracellular Ca(2+) sensitivity being 1.1 +/- 0.02 mmol/L for normal and 1.2 +/- 0.02 mmol/L for adenomatous cells (P = .02). (2) There was no overall correlation between PTH secretion and gland morphology. (3) In 5 of 7 cases, PTH secretion correctly predicted the decrease in IO-PTH., Conclusion: Parathyroid adenomas generally exhibit abnormal PTH secretory function; however, enlarged parathyroid glands that do not contribute to the biochemical changes of hyperparathyroidism do exist, and, in these cases, cellular secretory function is a useful predictor of IO-PTH dynamics.

Background: The development of localization studies and quick parathyroid hormone assay (QPTH) has allowed the development of focused surgery in sporadic primary hyperparathyroidism. The aim of this investigation was to determine whether localization studies select a specific population of patients., Methods: From 1999 to 2001, 213 patients underwent surgery for sporadic primary hyperparathyroidism. All were investigated with sestamibi scanning and ultrasonography. When at least 1 study showed a positive result (n=175), the patient underwent a video-assisted approach with QPTH. When results were negative (n=38), the patient underwent cervicotomy and exploratory procedures of all 4 parathyroid glands., Results: All patients are cured (mean follow-up, 17.8+/-10.3 months [SD]). Patients with negative preoperative study results had a high risk of multiglandular disease (12/38 patients; 31,6%), compared with patients with 1 positive study result (3/83 patients; 3.6%; P<.0001) and those with 2 concordant positive study results (0/92 patients; P<.0001)., Conclusion: When preoperative localization study results are negative, the patient has a high risk of multiglandular disease, and a conventional cervicotomy with identification of the 4 glands is recommended strongly. When only 1 localization study is positive, the risk of multiglandular disease justifies the use of QPTH during a focused approach. When positive localization study results are concordant, the use of QPTH is questionable during a focused approach.

Background: Upon explant, parathyroid tissue (PTH) upregulates vascular endothelial growth factor (VEGF), a potent endothelial cell mitogen, yet PTH induces a more robust angiogenic response than VEGF alone. This implies that other angiogenic factors are also produced. We tested PTH for production and function of angiopoietin-2 (Ang-2), a protein known to modulate VEGF response., Methods: With use of reverse transcriptase-polymerase chain reaction and SELDI (Surface Enhanced Laser Desorption/Ionization) (Ciphergen, Freemont, Calif) technology, we tested explanted PTH for Ang-2 production and determined the time sequence of Ang-2 upregulation. With use of an in vitro rat microvessel angiogenesis assay, we determined the angiogenic response to PTH-produced Ang-2., Results: Ang-2 messenger RNA was induced within 1 hour of parathyroid explant, with a maximum level detectable at 24 hours. Ang-2 protein production was maximal at 24 hours, with elimination by 48 hours. Ang-2 supplemented gels appeared to prompt earlier angiogenic induction, whereas sequestration of Ang-2 with soluble Tie2 receptor appeared to delay angiogenic induction. Soluble Tie2 treatment did not significantly decrease cumulative microvessel length, and no significant increase in neovessel length was seen with Ang-2 supplemented gels., Conclusions: PTH upregulates Ang-2 upon explantation, with peak protein production by 24 hours. Ang-2 appears to functionally enhance initiation of PTH-induced angiogenesis, although the ultimate neovessel length appears to be dependent on other PTH-produced factors.

Background: Technetium-99m-sestamibi (sestamibi) is the imaging agent of choice for preoperative parathyroid localization. The subcellular localization of sestamibi uptake in enlarged parathyroid glands in patients with hyperparathyroidism has not been determined. This study investigated the mechanism of retention of sestamibi by human parathyroid tissue., Methods: Twenty-three freshly harvested and 15 cryopreserved parathyroid glands excised from patients with primary or secondary hyperparathyroidism were analyzed for subcellular localization of Tc-99m-sestamibi. Tissues were incubated with 100 microCi of sestamibi and isolated for mitochondria by differential centrifugation, and the integrity of subcellular fractions was quantified with the mitochondrial enzyme marker, succinate dehydrogenase., Results: Ninety-two percent of sestamibi activity was associated with mitochondria. Furthermore, after adding the mitochondrial uncoupler, carbonylcyanide m-chlorophenylhydrazone (CCCP), to fresh parathyroid tissues, 84.96% and 73.86% of sestamibi was released from the mitochondrial and tissue fragment components, respectively. In addition, sestamibi activity in the mitochondrial component of cryopreserved human parathyroid tissue decreased to the same amount as the CCCP-treated group., Conclusions: These data confirm that mitochondrial activity is the major component of sestamibi uptake by human parathyroid tissue in patients with hyperparathyroidism.

Background: Parathyroid tissue expresses the T-lymphocyte antigens CD3 and CD4, and parathyroid CD3 has earlier been proposed to interact in the regulation of parathyroid hormone (PTH) release., Methods: Anti-Leu3a, a monoclonal antibody recognizing CD4, was used to stain parathyroid tissue immunohistochemically, to influence PTH secretion from enzymatically dispersed parathyroid cells, and to immunoprecipitate parathyroid CD4. Northern blot and polymerase chain reaction were used to clarify the similarity between parathyroid and lymphocytic CD4. Serum PTH level was measured with an immunoradiometric assay in healthy control subjects and individuals with human immunodeficiency virus type 1., Results: The parenchyma of normal and abnormal parathyroid tissue displayed strikingly variable CD4 expression. Immunoprecipitation showed a 56 kd molecule, and Northern blot and polymerase chain reaction confirmed the similarity with lymphocyte CD4. Anti-Leu3a inhibited preferentially low calcium-stimulated secretion of PTH from dispersed parathyroid cells, without discernible influences on the cytoplasmic calcium concentration of these cells. Individuals with human immunodeficiency virus type 1 displayed significantly lower serum PTH levels than healthy control subjects., Conclusions: The results suggest that the human parathyroid chief cell expresses a CD4 moiety, which seems to interact in the PTH release in vitro and in vivo and which seems to use another second messenger system than the structurally similar T-cell equivalent.

Background: Localization of parathyroid glands is critical in the treatment of recurrent or persistent hyperparathyroidism. Technetium sestamibi imaging may improve localization; however, the mechanism of visualization of parathyroid tissue remains unclear. On the basis of the chemical structure of sestamibi it has been suggested that p-glycoprotein is involved in the transport of sestamibi across cell membranes. This study was designed to examine sestamibi uptake and retention and p-glycoprotein expression in normal and abnormal parathyroid tissue., Methods: Thirty-two consecutive patients underwent 2-methoxy-isobutyl-isonitrile imaging immediately before parathyroid exploration. Tissue was obtained from normal and abnormal parathyroids and from the thyroid gland. Touch preparations gave rapid confirmation of tissue origin. Specimens were trimmed and weighed, and gamma-emission was counted. Percentage injected dose per gram of tissue was calculated. Immunohistochemistry was obtained with a battery of monoclonal antibodies to identify p-glycoprotein in parathyroid tissue submitted for permanent histologic examination. Slides were graded by a pathologist familiar with immunohistochemistry., Results: Abnormal parathyroid tissue had a higher mean retention of injected dose per gram than did normal thyroid and parathyroid tissue. Immunohistochemistry revealed that abnormal parathyroid tissue expresses less p-glycoprotein., Conclusions: These results suggest that size is not the single determinant of parathyroid visualization and that p-glycoprotein expression may be involved in the mechanism of parathyroid imaging.

Background: Hyperparathyroidism affects most patients with multiple endocrine neoplasia type 1 (MEN 1). This study investigates expression of the candidate MEN1 gene phospholipase C beta 3 (PLC beta 3) and expression and function of a putative calcium sensing protein (CAS) in hyperparathyroidism of MEN 1., Methods: In 31 parathyroid glands from 17 patients with MEN 1, CAS distribution was studied immunohistochemically and parallel sections were explored for PLC beta 3 mRNA expression by in situ hybridization. Enzymatically dispersed parathyroid cells were analyzed for cytoplasmic calcium concentrations [Ca2+]i and parathyroid hormone (PTH) release., Results: All glands exhibited a heterogeneously reduced CAS immunoreactivity, especially meager in nodularly assembled parathyroid cells. Calcium regulated [Ca2+]i and PTH release tended to be more deranged in the glands possessing the lowest immunostaining. Parathyroid PLC beta 3 invariably was homogeneously expressed, and this included even MEN 1 patients with reduced PLC beta 3 expression in endocrine pancreatic tumors., Conclusions: The findings support variable calcium insensitivity of [Ca2+]i and PTH release in hyperparathyroidism of MEN 1, apparently coupled to heterogeneously reduced CAS expression. For clarification of the role of PLC beta 3 in MEN 1 parathyroid tumorigenesis further study of this protein is required.

Background: Normal and abnormal human parathyroid tissue express the T-lymphocyte protein CD4, and parathyroid and lymphocyte cells show similarities with respect to mechanisms of calcium permeability and regulation of the cytoplasmic calcium concentration., Methods: Anti-Leu4, a monoclonal antibody recognizing the T-lymphocyte glycoprotein complex CD3, is used to immunohistochemically stain normal and abnormal human parathyroid cells and to explore influences on the parathyroid hormone (PTH) secretion of enzymatically dispersed parathyroid cells., Results: Parathyroid glands of patients with different forms of hyperparathyroidism displayed variable expression of the anti-CD3 reactive complex. The stainings correlated both positively and inversely to immunoreactivity for a previously defined calcium sensor, the decreased expression of which may constitute a molecular basis for hyperparathyroidism. Incubation of parathyroid cells with the anti-Leu4 antibody inhibited PTH secretion and reduced its sensitivity to external calcium without influence on parathyroid cytoplasmic calcium concentration., Conclusions: The results suggest that the human parathyroid cells express a CD3-like molecule with the ability to interact in PTH release.

Background: Approximately 10% of patients taking lithium for manic-depressive disorders become hypercalcemic. It remains unclear whether lithium initiates disease or promotes underlying hyperparathyroidism. We have previously demonstrated that at therapeutic concentrations lithium stimulates in vitro incorporation of both tritiated thymidine and bromodeoxyuridine into abnormal human parathyroid tissue, reflecting growth-promoting properties. Whether lithium has similar growth-promoting properties in normal parathyroid tissue remains unresolved., Methods: We infused lithium (0 mmol/L, 3 mmol/L, or 10 mmol/L) through implantable subcutaneous pumps into normal rats for 3 months and measured levels of serum lithium, serum calcium, and serum parathyroid hormone (PTH) (with a radioimmunoassay specific for rat PTH 1-34.) On completion of the infusion, bromodeoxyuridine (30 mg/kg) was administered intraperitoneally. The parathyroid glands were removed and measured in two dimensions to calculate gland volume [V = (pi/6) x (d1) x (d2)2.] Parathyroid incorporation of bromodeoxyuridine was assessed by using immunocytochemistry., Results: Serum lithium level was significantly (p < 0.05) different between groups and constant within groups. Levels of serum calcium and PTH were inversely related to each other; however, no significant differences were noted between groups with respect to level of serum calcium or serum PTH at any measurement. Similarly, no significant differences were noted between groups with respect to gland size or number of bromodeoxyuridine-positive cells., Conclusions: Long-term lithium infusion in rats for a period representing approximately 15% of their life span failed to evoke changes in parathyroid gland size or function. These data are consistent with (1) lithium as a promoter of hyperparathyroidism and (2) resection of abnormal parathyroid tissue and resumption of lithium for patients requiring long-term therapy.

We have recently validated a reverse hemolytic plaque assay (RHPA) for the quantitative measurement of parathyroid hormone release from single isolated parathyroid cells. The information regarding secretory behavior of normal and abnormal parathyroid tissue has been based previously on fluorescent spectroscopy or quantification of immunoreactive parathyroid hormone by radioimmunoassay. Thus, individual differences in secretion and assessment of viability are not clearly measured in these types of experiments. The RHPA has the advantage of allowing measurements of secretory activity in individual viable parathyroid cells. In this report, we have modified the RHPA to measure the release of parathyroid hormone from human cells. This is the first instance of measurement of hormone secretion from human cells, and we present data indicating the specificity of the assay for human parathyroid hormone. The response of normal human parathyroid cells to alterations in extracellular calcium was assessed by two parameters: the ability of an individual cell to secrete parathyroid hormone in response to a stimulus and the recruitment of normal human cells to release parathyroid hormone. This assay will allow elucidation of secretory dynamics in normal and abnormal glands, which may help us to understand the mechanisms involved in parathyroid dysfunction.

Background: The purpose of this study was to clarify the relationships of extractable and secreted parathyroid hormone (PTH) and parathyroid secretory protein (PSP) in human parathyroid tumors to PTH messenger RNA (mRNA), PSP mRNA, and cell replication., Methods and Results: In tissue cultures of seven adenomas and five secondary hyperplasias, we found a direct correlation for secreted PTH versus PSP for both adenomas and secondary hyperplasias. Secreted PTH:PSP was elevated for adenomas (11:1) compared to that of secondary hyperplasias (2:1), and adenomas secreted significantly more PTH and PSP than did secondary hyperplasias. In extracts of eight adenomas and six secondary hyperplasias, the ratio of PTH:PSP was unexpectedly low (2:1) and similar for both adenomas and secondary hyperplasias. The ratio of extractable PTH mRNA:PSP mRNA was extremely low for both adenomas (1:7) and for secondary hyperplasias (1:5). Flow cytometry indicated that percent replication was inversely correlated with PTH mRNA and PSP mRNA., Conclusions: Increased PTH secretion by adenomas cannot be attributed to increased biosynthetic capacity because it is less than expected. Hypersecretion of PTH by adenomas and coincident marked reductions in PTH mRNA suggest either a defect in cytoplasmic storage of PTH or impairment of normal posttranslational degradation of PTH. As parathyroid tumor cells increase replication, PTH mRNA is reduced. Possible explanations for this include decreased PTH gene transcription or decreased mRNA half-life.

Background: To explain the decreased success of cryopreserved versus fresh parathyroid autotransplants, we investigated the effect of cryopreservation on parathyroid function., Methods: Parathyroid cryopreserved tissue from surgical specimens of 18 patients was analyzed in a comparative fashion with 10 fresh abnormal glands. Cell viability was evaluated by a double-fluorescence technique, and parathyroid hormone secretion was detected from individually dispersed parathyroid cells with the reverse hemolytic plaque assay. The plaque area reflected the amount of parathyroid hormone secreted by each cell, and the percentage of plaque-forming cells represented the number of secreting cells. Feedback regulatory mechanisms remained intact for both fresh and cryopreserved tissue as shown over a wide range of calcium concentrations., Results: The percentage of viable cells from fresh and cryopreserved tissue was always in excess of 88%. No significant difference was noted in the percentage of plaque-forming cells nor the amount of hormone released per individual cell comparing fresh and cryopreserved glands (6 months to 2 years). Specifically, at physiologic calcium concentrations no significant differences existed in the secretory behavior between fresh and cryopreserved tissue., Conclusions: Without showing decreased viability or parathyroid hormone secretion after cryopreservation, the cause of graft failure in cryopreserved tissue still remains unknown.

Patients receiving lithium for the management of manic depressive disorders appear to be at increased risk for development of hypercalcemia. Some (but not all) clinical studies and several in vitro studies suggest that lithium alters release of parathyroid hormone. Because hypercalcemia may result from an increase in the mass of parathyroid tissue, we studied the in vitro effect of lithium on tritiated thymidine (3H-TdR) incorporation as a measure of DNA synthesis. Dispersed cells from previously cryopreserved tissue from 18 patients undergoing surgery for single-gland hyperparathyroidism (adenoma) and five patients with secondary hyperparathyroidism were incubated with graded concentrations of lithium chloride and, after a 5-day incubation, were pulsed with 3H-TdR. Adenoma cells exposed to 2.0 mmol/L lithium (therapeutic level is approximately 0.8 to 2.0 mmol/L) demonstrated increased 3H-TdR incorporation compared with cells not exposed to lithium (average increase 56%). Secondary hyperplasia cells exhibited a similar but less striking response. There was no lithium-induced 3H-TdR incorporation in four preparations with normal bovine parathyroid cells. We conclude that lithium in therapeutic doses increases 3H-TdR incorporation into adenoma cells, may serve as a mitogen for human parathyroid adenoma, and could promote or accelerate hyperparathyroidism.

It is not clear whether hypercalcemia and hyperparathyroidism associated with lithium therapy are the result of an unmasking of preexisting disease or a direct effect of lithium on the parathyroid glands. To investigate this phenomenon, parathyroid hormone (PTH) secretion and cytosolic calcium concentrations [( Ca]i) were measured in normal and lithium-treated dispersed bovine parathyroid cells grown in tissue culture and incubated with varying concentrations of extracellular calcium [( Ca]e) (0.5 to 2.5 mmol/L). Results indicate that lithium has two effects on parathyroid secretory response: (1) a decrease in low calcium-stimulated PTH release and (2) a potentiation of PTH release at physiologic concentrations of extracellular calcium. [Ca]i was assessed by use of fura-2, a calcium-sensitive fluorescent indicator. Resting [Ca]i levels were unaffected by lithium (103 +/- 13 nmol/L in controls vs 101 +/- 5 nmol/l in lithium-treated cells, mean +/- SE). Subsequent increases in [Ca]i in response to increases in [Ca]e were significantly less in lithium-treated cells, with no difference at maximal [Ca]e. Increases in [Ca]i in response to a submaximal concentration of extracellular magnesium were also blunted in cells pretreated with lithium. In conclusion, our data suggest that, at physiologic calcium concentrations, lithium decreases parathyroid cell sensitivity to changes in [Ca]e, reducing [Ca]i levels and increasing PTH secretory response.

Because insulin-dependent diabetes mellitus is associated with altered electrolyte metabolism and a derangement of the parathyroid hormone (PTH)-vitamin D endocrine system, we studied 23 children with diabetes (age 9.4 +/- 2.5 years) and found lower serum values for total and ionized calcium, magnesium, intact PTH, calcitriol, and osteocalcin than in age- and sex-matched control subjects. All patients were given magnesium orally (6 mg/kg daily of elemental magnesium) for up to 60 days. During treatment, serum magnesium, total and ionized calcium, intact PTH, calcitriol, and osteocalcin concentrations significantly increased, reaching control values. After a 3-day low-calcium diet, the patients had a significantly reduced delta-increment of PTH and calcitriol in comparison with values obtained during hypomagnesemia. After magnesium repletion, the delta-increments of both PTH and calcitriol, in response to the low-calcium diet, were not significantly different from control values. These data suggest that magnesium deficiency plays a pivotal role in altering mineral homeostasis in insulin-dependent diabetes mellitus.

The surgeon's gross evaluation, the hematoxylin and eosin stain, which assesses extracellular fat, and a new intracellular fat stain, osmium carmine, were comparatively evaluated in 30 consecutive patients who underwent surgery for primary hyperparathyroidism. The surgeon's gross judgment of enlarged and normal parathyroid tissue resulted in the correct functional assessment in 98% and 97% of the glands, respectively. The surgeon's functional assessment was correct in seven of 10 parathyroid glands that were considered by gross examination to be slightly enlarged (50 to 80 mg). The osmium carmine intracellular fat stain provided a correct functional assessment in all 10 of these glands. The osmium carmine stain also appears to have a role in providing scientific quantitative data to limit operations in patients who have a parathyroid adenoma to removal of the adenoma and biopsy of a grossly normal gland that demonstrates normal intracellular fat. Only one side of the neck was explored in 11 patients who fulfilled these criteria. There has been no persistent or recurrent hypercalcemia in these patients.

The functional evolution of autogenous parathyroid grafts was monitored in six patients with primary parathyroid hyperplasia using a sensitive radioimmunoassay specific for the midregion of parathyroid hormone (PTH). After successful total parathyroidectomy and graft implantation in the forearm, basal immunoreactive PTH (iPTH) fell to undetectable levels for about 12 to 18 weeks, and then rose to normal. By 3 weeks after surgery, an iPTH increment appeared in venous blood from the arm bearing the graft. Graft function was demonstrated in all six cases. Graft-independent hypercalcemia occurred in two patients and appeared to inhibit PTH secretion by the graft. In one case, elevated levels of calcium and iPTH persisted after surgery but iPTH remained equal in both arms. At 5 months, a fifth hyperplastic gland was resected from the mediastinum, and the calcium level decreased to normal; the parathyroid implant was secreting iPTH vigorously 5 days later. Hypercalcemia had not prevented establishment of a viable implant. In the second case, hypercalcemia developed 80 weeks after operation, and the previously demonstrated iPTH gradient disappeared; presumably a fifth gland had become hyperplastic. In this patient, iPTH had remained in the upper portion of the normal range during the first postoperative week, probably indicating the potential for recurrence. Each of the other five patients remains normocalcemic 4 to 103 weeks after grafting.

Although the oxyphil cells of the human parathyroid generally are not thought to be involved in the secretion of parathyroid hormone, there have been numerous reports in the literature describing functional oxyphil cell adenomas. We reviewed 453 consecutive parathyroid explorations in 446 patients over a 13-year period and identified 15 patients whose hyperparathyroidism had been caused by adenomas composed almost exclusively of oxyphil cells. All patients were relieved of their hypercalcemia postoperatively, and there have been no recurreness during a mean follow-up of 40 months (100% follow-up). Three patients have died, all without evidence of recurrent hyperparathyroidism at the time of death. Immunoperoxidase and ultrastructural studies confirm that oxyphil cells from these adenomas contain parathyroid hormone and suggest that they are capable of secretory activity. A review of the literature showed that functional oxyphil adenomas occur more frequently than is usually appreciated, although they are an uncommon cause of primary hyperparathyroidism.

The cross sections of hyperplastic glands removed during total parathyroidectomy in patients with renal osteodystrophy were classified on the basis of macroscopic and functional criteria. Diffuse (type 1) and nodular (type 2) glands could be distinguished macroscopically. Functional in vitro studies showed no significant difference in suppressibility and basal parathyroid hormone (PTH) secretion (61% and 74%, respectively). In both types of glands A, B, C, and D regions could be distinguished with use of a stereo magnifier (magnification, x10 to x16). In diffuse A regions containing stroma fat cells, PTH secretion could be suppressed optimally (more than 50% of maximum secretion) in more than 90% of all specimens in vitro. In diffuse B regions containing no fat cells, hormonal secretion could be suppressed in only 17% and 25%, respectively. Confined (oxyphilic or chief cell) nodules (C regions), only found in type 2 glands, could be suppressed in 18%. Nodules of "degenerating" oxyphilic cells (D regions), only found in type 2 glands, were suppressible, but the low PTH secretion indicated degenerative processes. Thus only fragments from A regions should be selected for autotransplantation.

Parathyroidectomy is usually followed by a decrease in serum calcium, a lessening of symptoms, and a normocalcemic state that continues for years. Evaluation of parathyroid gland function after parathyroidectomy over a protracted period showed a continued hypersecretory state in many normocalcemic patients and is reported here for the first time. Patients identified with parathyroid hyperplasia (more than one gland excised) and patients who later developed mild renal failure were excluded. Seventy-seven patients undergoing parathyroidectomy with only one enlarged gland removed and the other normal-sized glands viewed or examined by biopsy were followed up from 5 to 16 years. Two patients developed recurrent hypercalcemia at 4 and 9 years after surgery. Seventy-five patients are considered "cured" and have normal serum calcium values. However, 28 (37%) of these normocalcemic patients have persistent elevations of parathyroid hormone. This increased parathyroid gland function suggests a continuing stimulation of the remaining glands. The rarity of clinical recurrence may be related to effective adaptations that prevent overt hypercalcemia. Many parathyroid adenomas appear to represent nonneoplastic disease.

Sixteen patients with generalized primary parathyroid hyperplasia were treated with attempted total parathyroidectomy and placement of an autogenous parathyroid graft in the forearm musculature; these patients have been followed for up to 79 months. We assessed completeness of parathyroidectomy on the basis of the background immunoreactive parathyroid hormone (iPTH) value 3 to 7 days after surgery, which predicted the chance of a graft-independent recurrence or persistence of hyperparathyroidism (0/8 if undetectable versus 4/5 if normal or high). Total parathyroidectomy was sometimes difficult to achieve because of the presence of supernumerary or ectopic parathyroid glands; to enhance the success rate of total parathyroidectomy, we suggest both the use of preoperative ultrasonography to locate intrathyroidal parathyroids and a routine search for supernumerary parathyroids that includes transcervical thymectomy. Graft function was monitored by measuring the secretory gradient for iPTH (the difference between the two antecubital fossae). Gradients on postoperative days 3 to 7 were barely detectable, but by 3 weeks, larger iPTH gradients were noted in every case. By 4 months, the graft could maintain normal serum calcium levels in all but one case. Autonomous graft function has evolved in four of six evaluable patients with type I multiple endocrine neoplasia (MEN I), but in none of the nine patients with sporadic hyperplasia (p = 0.043). A prospective study is needed to determine whether the use of a smaller number of parathyroid fragments for the autogenous graft in known MEN I patients might delay recurrence.

We studied parathyroid hormone (PTH) release from cell suspensions of fresh and cryopreserved human parathyroid tissue. A sensitive PTH assay with midregion specificity and adaptation of "micro" methods of cell plating permitted conservation of tissue (200 microliters aliquots) and high reproducibility (5 to 10 aliquots per experimental condition). Viability of cells in suspension was confirmed by increased PTH release with increased incubation, increased incorporation of tritiated leucine with increased incubation, and incorporation of tritiated leucine following experimental incubation. Because of conflicting reports regarding the in vivo effect of cimetidine on PTH release, we incubated cells from both adenomatous and hyperplastic glands at 0, 10(-4)M, 10(-5)M, and 10(-6)M cimetidine (10(-5)M is therapeutic) and at 0.25, 1 to 1.2, and 2 mM Ca++. Despite occasional statistically significant (P = 0.05) differences in PTH release with and without cimetidine, therapeutic levels of cimetidine had no consistent effect on PTH release from pathologic parathyroid tissue in vitro.

The hormone secretion from human parathyroid tissue autografted after cryopreservation can fail frequently. In this study we examined the effects of the cryopreservation procedure on parathyroid hormone secretion in vitro and the viability of parathyroid cells to identify possible reasons for graft failure. Cryopreservation did not affect quantitative parathyroid hormone release from single-cell suspensions or its calcium-and magnesium-dependent regulatory mechanisms. However, morphometric analysis of thawed 1 mm3 graft particles showed various degrees of necrosis when compared with fresh grafts. Thus partial necrosis of cryopreserved tissue appears to contribute to poor transplantation results compared with immediate replantation of fresh parathyroid tissue. This limitation can be overcome by increasing the number of frozen graft particles used for autotransplantation. The percentage of viable cells should be accounted for by morphometric analysis and this factor used when calculating the number of graft particles employed.

Bovine parathyroid tissue was evaluated as a model to compare parathyroid hormone-related peptide (PTH-rP) and parathyroid hormone (PTH) secretion. Tissue was incubated in variable calcium levels (n = 5). A parathyroid cell digest was prepared from collagenase-treated glands. PTH-rP and PTH levels were determined by radioimmunoassay. PTH-rP bioactivity was determined by 3H-cAMP production in a UMR 106 cell bioassay. PTH-rP levels in the incubation medium were 2.0 ng/mg protein (0.25 mmol Ca++), 2.2 ng/mg protein (1.25 mmol Ca++), and 1.9 ng/mg protein (2.5 mmol/L Ca++). PTH levels were 321 ng/mg protein (0.25 mmol/L Ca++) and 200 ng/mg protein (2.5 mmol Ca++). Therefore, calcium significantly inhibited PTH but not PTH-rP secretion (p = 0.03). Addition of incubation medium to the bioassay resulted in 3H-cAMP levels that were 8 to 10 times greater than basal levels. Greater than 50% of the activity persisted after addition of PTH antibody, demonstrating that a significant amount of the activity was caused by PTH-rP. Tissue PTH-rP was 5.1 ng/mg protein, compared with 2080 ng/mg protein for PTH. We conclude that (1) bovine parathyroid tissue contains bioactive PTH-rP and is a useful model to compare the biosynthesis and secretion of PTH-rP and PTH in normal tissue and (2) unlike PTH, PTH-rP secretion is not regulated by calcium.