Postoperative Elevated Serum Levels of Intact Parathyroid Hormone after Surgery for Parathyroid Adenoma: Sign of Bone Remineralization and Decreased Calcium Absorption

Increased levels of intact parathyroid hormone (PTH) have been documented after surgery for primary hyperparathyroidism (pHPT) despite normocalcemia. The pathogenesis remains to be elucidated. Seventeen consecutive patients operated on for solitary parathyroid adenoma were investigated before and at 8 weeks and 1 year after surgery with serum levels of intact PTH, biochemical variables known to reflect PTH activity, and bone mineral content (BMC). In addition, an oral calcium loading test was performed 8 weeks after the operation. All patients had low or normal serum calcium levels during follow-up. Eight weeks after operation six patients (35%) had an increased serum PTH level. These patients (group I) preoperatively had higher serum levels of PTH and alkaline phosphatase than patients with normal PTH levels (group II). They also had lower BMC and larger parathyroid adenomas. They did not differ in renal function. At 8 weeks after operation group I showed higher mean serum levels of osteocalcin and propeptide of type I procollagen but lower urinary calcium excretion. In contrast to patients in group II, they also showed a lower calciuric response and a trend to a lower calcemic response during the oral calcium load. The two groups showed similar parathyroid sensitivity for calcium. Patients in group I demonstrated a significant increase in BMC the first year after the operation. Increased serum PTH 8 weeks after surgery for sporadic parathyroid adenoma was not due to persistent pHPT or impaired renal function. Instead, the results imply there is diminished calcium absorption and increased bone turnover with cortical bone remineralization.     

Preoperative Serum Osteocalcin may Predict Postoperative Elevated Parathyroid Hormone in Patients with Primary Hyperparathyroidism

Background  

Persistent postoperative elevation of parathyroid hormone (POePTH) following successful parathyroidectomy for primary hyperparathyroidism (PHPT) is presumed to result from bone remineralization. Predicting which patients may need treatment is difficult. This study investigated whether preoperative serum osteocalcin (OC), a bone turnover marker involved in mineralization, can predict POePTH.     

Sequential Changes in Plasma Intact and Whole Parathyroid Hormone Levels during Parathyroidectomy for Secondary Hyperparathyroidism

Most commercial assays for intact parathyroid hormone (iPTH) cross-react with non-PTH1-84 fragments (likely to be PTH7-84). We aimed to evaluate a whole PTH assay that measured only PTH1-84 by comparing it with an assay measuring iPTH levels during parathyroidectomy in secondary hyperparathyroidism (HPT). Twenty-eight patients with secondary HPT who underwent total parathyroidectomy with autotransplantation served as subjects. Blood samples for postoperative assay were drawn after anesthesia; immediately prior to excision of the last parathyroid gland; and at 5, 10, and 15 minutes after excision. The PTH7-84 level was calculated by subtracting the whole PTH value from the iPTH value. Plasma whole PTH decreased more rapidly than iPTH after parathyroidectomy (p < 0.0001). PTH levels that decreased by 50% or more from levels prior to excision to 10 minutes after excision were used to predict successful parathyroidectomy; decreases in whole PTH substantiated curative surgery for all patients without introducing false-positive and false-negative results. iPTH levels decreased by at least 50% in only 16 patients at 10 minutes after excision without false-positive results. Out of 11 cases in which iPTH decreased less than 50%, two were true-negatives and nine were false-negatives. Decreases in whole PTH levels more accurately reflect surgical outcome than do decreases in iPTH levels during parathyroidectomy in secondary HPT patients. Even though the quick iPTH assay is used infrequently during surgery for secondary HPT, our results suggest that a quick whole PTH assay may be more useful than the iPTH assay currently used in parathyroidectomy procedures for secondary HPT.     

Persistent Hypocalcemia with Elevated Parathyroid Hormone Levels After Long-Term Primary Hyperparathyroidism: Report of a Case

We report herein the case of a 48-year-old man with long-term persistent primary hyperparathyroidism (pHPT) despite undergoing a parathyroidectomy in 1976, followed by a reoperation in 1978, for whom resection of a parathyroid adenoma in the upper mediastinum was eventually performed. His postoperative course was complicated by recurrent hypocalcemia refractory to oral calcium substitution and significantly elevated levels of parathyroid hormone (PTH). The radiological findings are presented, and we discuss the possible reasons for the coincidence of severe hypocalcemia with increased PTH levels in association with pHPT. Received: October 18, 1999 / Accepted: May 30, 2000     

Dynamics of Parathyroid Hormone Secretion After Total Parathyroidectomy and Autotransplantation

Background  Secondary hyperparathyroidism is a common complication in uremic patients. Total parathyroidectomy combined with partial autotransplantation into brachioradialis muscle has been the preference among the options for surgical treatment. This study was designed to evaluate the reserve and ability of suppression of autotransplanted parathyroid tissue using dynamics tests. Methods  We studied, prospectively, 12 patients in recent (RP) and late (LP) postoperative of total parathyroidectomy with autotransplantation. For analysis of the secretory reserve capacity, we induced hypocalcemia by ethylenediaminetetraacetic acid (EDTA) infusion. Furthermore, for analysis of the ability for parathyroid hormone (PTH) suppression, the hypercalcemia test was used, by intravenous administration of calcium in LP. Results  In RP, there was a decrease in the average serum levels of PTH, phosphorus, and alkaline phosphatase, which ranged from 13 to 231 (87 ± 65) pg/ml, 2.3 to 6.2 (3.3 ± 1.1) mg/dl, and 77 to 504 (250 ± 135) U/L, respectively, similar to that observed in LP. The analysis of the average curve of variations in PTH during testing of the stimulus with EDTA showed lack of secretion in RP and partial response in LP. Impaired suppression ability of the graft in LP was observed in the test with intravenous calcium. Conclusions  Total parathyroidectomy followed by partial autotransplantation was effective in reducing PTH serum levels in patients with terminal kidney disease. The elevation of serum calcium during the suppression test was not able to inhibit the autograft gland secretion of PTH. The assessment of parathyroid graft function demonstrated an inability to respond to the stimulus of hypocalcemia induced by EDTA, although there was a partial recovery, in late postoperative period.     

Intra-operative Parathyroid Hormone Monitoring in Patients with Parathyroid Cancer

Background Intra-operative parathyroid hormone (PTH) monitoring (IPM) is 97% accurate in predicting postoperative eucalcemia in sporadic primary hyperparathyroidism (SPHPT). However, its usefulness in parathyroid cancer has not been demonstrated. This study reports IPM accuracy during surgical resections for parathyroid cancer. Methods Eight of 556 consecutive patients with SPHPT underwent parathyroidectomy using IPM and had parathyroid cancer. Operative success was defined as eucalcemia > six months and operative failure/persistent cancer as hypercalcemia within six months of parathyroidectomy. The IPM criterion for operative success was defined as a >50% decrease of peripheral PTH levels from the highest either pre-incision or pre-excision values, 10 minutes after resection. Results In eight patients, 11 operations were performed. Ten operations (91%) resulted in >50% intra-operative PTH decrease. However, in only seven (70%) of these resections, eucalcemia was achieved for >6 months with five of these seven (71%) procedures being initial en bloc resections. The remaining 3/10 (30%) operations with >50% intra-operative PTH decrease resulted in operative failures. In the last operation, intraoperative parathormone monitoring (IPM) correctly predicted operative failure. IPM sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy in predicting outcome were 100, 40, 70, 100, and 75%, respectively. Conclusions IPM with the criterion of >50% PTH drop from the highest level is less accurate in predicting operative success in parathyroid cancer when compared to SPHPT. A >50% intra-operative PTH level decrease in patients with parathyroid cancer, particularly in reoperative cases, is less predictive of complete resection. The initial recognition of this disease followed by proper resection remains essential in the treatment of parathyroid cancer.     

Elevated Serum Arginase Activity Levels in Patients with Breast Cancer

Purpose. Recently, the high activity of arginase enzyme has been observed in the sera of malignant neoplasms. In this pathogenic condition, it is said that arginase strongly inhibits lymphocyte proliferation and plays a role in providing ornithine as a substrate for biosynthesis of polyamines, which have been found in various types of cancer. The aim of this study was to examine the arginase activity levels in breast cancer as a marker.Methods. We evaluated the serum arginase activity levels in 48 females with breast cancer, in 30 females with benign disease, and in 50 healthy control subjects. The serum arginase activities were determined according to the slightly modified method of Chinard.Results. The mean activity of arginase was found to be high in the early stages (n = 27, stage I + II, P 0.01), and higher in the advanced states (n = 21, stage III + IV, P 0.001) of the malignant group in comparison with those of the normal subjects.Conclusion. A high arginase level in breast cancer was observed to possibly be released into the serum: namely, the more advanced the breast cancer, the higher the serum level of arginase enzyme activity. Therefore, this enzyme might serve as a useful biological marker in breast cancer while also being an indicator of breast cancer progression.     

Impact of Intraoperative Parathyroid Hormone Levels on Surgical Results in Patients with Renal Hyperparathyroidism

The aim of our study was to evaluate the impact of intraoperative parathyroid hormone (PTH) measurement on surgical results in patients with renal hyperparathyroidism (HPT). From December 1999 to February 2004, a series of 95 consecutive patients underwent total parathyroidectomy and intraoperative PTH measurement for renal HPT. Intraoperative PTH was measured before and 15 minutes after parathyroidectomy with the Immulite DPC assay for intact PTH. The median PTH levels before surgery were 133.0 pmol/L, which declined to 5.9 pmol/L at the end of the operation. At follow-up, 91 of 95 (96%) patients presented with normal calcium levels. Persistent renal HPT was seen in three patients, and recurrent HPT was diagnosed in another. In 99% of the patients the intraoperative PTH levels declined more than 50% and in 73% the PTH decay was more than 90%. In 64% of the patients PTH levels dropped into the normal range (< 7.6 pmol/L). Altogether, 97% of the patients with an intraoperative PTH decrease of more than 90% presented with normal PTH levels postoperatively (p = 0.0237), as did all of the patients whose intraoperative PTH dropped into the normal range (p = 0.0432). Intraoperative PTH measurement with a decrease in intraoperative PTH of at least 90% is highly predictive of successful parathyroidectomy and normalization of postoperative calcium and PTH levels.     

Changing Intraoperative Parathyroid Hormone Collection Sites from Peripheral to Central Does Not Affect Predictive Accuracy during Minimally Invasive Parathyroidectomy

Background

Intraoperative parathyroid hormone (ioPTH) monitoring (IPM) is vital to minimally invasive parathyroidectomy. Techniques vary in assay sampling, potentially affecting predictive accuracy of operative success. Initial guidelines were established using peripheral sites, but central sites may be preferred or necessary when peripheral access is not feasible. We hypothesize that changing collection sites from preexcision peripheral sites to postexcision central sites would not affect IPM accuracy.

Methods

Analysis of 64 consecutive patients who underwent parathyroidectomy for primary hyperparathyroidism was undertaken. PTH assays were collected simultaneously from a peripheral vein (PV) and central vein (CV) preexcision and at a 10-min interval after initial parathyroid excision. IPM success was defined as PTH decrease ≥50% 10 min after initial excision. Predictive accuracy was determined by the need to resect another abnormal gland and biochemical normalization in the postoperative clinic. Receiver operating characteristic (ROC) method with area under the curve (AUC) compared diagnostic accuracy of different assay approaches.

Results

Centrally, a statistically higher mean pre- and postexcision ioPTH of 391 pg/ml and 58 pg/ml was found compared with peripheral means of 156 pg/ml and 49 pg/ml, respectively (p < 0.001). The AUC when changing from a PV preexcision to a CV postexcision ioPTH was 0.89, comparable to AUC for peripheral or central assay collections alone (AUC = 0.83 and 0.85, respectively).

Conclusions

This study suggests that altering collection sites does not alter assay validity. In cases where peripheral sampling is compromised, changing from a peripheral to central sites will not likely alter the predictive accuracy of IPM significantly.     

Utility of Intraoperative Parathyroid Hormone Monitoring in Patients with Multiple Endocrine Neoplasia Type 1-Associated Primary Hyperparathyroidism Undergoing Initial Parathyroidectomy

Background

Intraoperative parathyroid hormone monitoring (IOPTH) is a widely used adjunct for primary hyperparathyroidism (pHPT). However, the benefit of IOPTH in familial pHPT, such as in multiple endocrine neoplasia type I (MEN1), remains unclear.

Methods

We performed a retrospective analysis of 52 patients with MEN1-associated pHPT undergoing initial parathyroidectomy with IOPTH monitoring at our institution. Parathyroid hormone (PTH) levels were measured before skin incision and 10 min after resection of the last parathyroid gland. Variables analyzed included percent drop of PTH from baseline and the final PTH level compared to the normal reference range (RR).

Results

A total of 52 patients underwent initial subtotal parathyroidectomy with IOPTH. An IOPTH decrease cutoff of ≥75 % from baseline had the highest biochemical cure rate (87 %). In the remaining 13 % who met this cutoff, all had persistent pHPT, with ≥90 % drop of PTH from baseline. The remaining patients, who did not meet the ≥75 % cutoff, were cured. Follow-up was available for three of four patients with final IOPTH levels above the RR: one had persistent pHPT, two had hypoparathyroidism (50 %). When a postresection PTH level was within the RR, 88 % of patients were cured. While considered cured from pHPT, 7 % of patients in this group developed permanent hypoparathyroidism. When the final PTH level dropped below the RR, 28 % developed permanent hypoparathyroidism.

Conclusions

A cutoff in IOPTH decrease of ≥75 % from baseline has the highest biochemically cure rate in patients with pHPT associated with MEN1. However, a 75 % cutoff in IOPTH decrease does not exclude persistent pHPT. The absolute IOPTH value does not accurately predict postoperative hypoparathyroidism.     

Parathyroid Hormone and Bone Marker Levels in Patients with Morbid Obesity Before and After Biliopancreatic Diversion

Background Scopinaro biliopancreatic diversion (BPD) is associated with malabsorption of calcium and vitamin D, which manifests as a secondary hyperparathyroidism (SHP) and may lead to osteopenia. Methods 96 morbidly obese patients were studied (age 19–60 years, 23 men and 73 women, with mean initial BMI 53) following intervention by Scopinaro BPD. The change in iPTH levels, urine DPD, Pyrilinks-D of DPC and serum CTx were studied at 0, 3, 6, 12, 18 and 24 months after surgery. Postoperatively, they were given supplements of calcium and vitamin D3. The control group consisted of 67 non-obese women and 10 men. Results The iPTH levels gradually increased after BPD, with a substantial difference compared to presurgery levels at month 6. In spite of the calcium and vitamin D supplements, 77% of the patients with presurgery SHP did maintain high levels of iPTH after 2 years.The percentage of SHP among the patients with normal pre-surgery iPTH was 58%. The basal figures of DPD/cre were significantly higher than in the control group, 9.06 (4.6–13.5) nM/mMcre vs 3.9 (2.8–5.6) in men and 6.75 (5.4–7.9) vs 7.67 (3.3–11.6) in women, but not CTx, 0.24 (0.02–0.89) vs 0.22 (0.07–0.55). After the operation, there was a noticeable increase which persisted at 2 years. There was a lack of correlation between the levels of iPTH and the bone resorption markers, i.e. the first ones decreased from month 6 in men and from month 12 in women, while the levels of iPTH continued to increase. Conclusion In obese patients, we found no correlation between iPTH levels and BMI. Supplements of calcium and vitamin D did not prevent the appearance of SHP following BPD. The patients with high pre-surgery iPTH levels have a higher risk of malabsorption of calcium and vitamin D. Following malabsorptive bariatric surgery, there is an increase in bone resorption, which results in DPD and CTx increase. Those markers do not correlate with iPTH, and this may suggest that there is a phenomenon of bone reshaping parallel to the loss of weight.     

Long-Term Effect of Different Dialysate Calcium Concentrations on Parathyroid Hormone Levels in Hemodialysis Patients

The appropriate dialysate calcium concentration (D[Ca]) for hemodialysis (HD) therapy has not yet reached a consensus. We have conducted a prospective control study for five years on the effects of different D[Ca] on serum intact parathyroid hormone (iPTH) levels. Patients were divided into three groups receiving different D[Ca] therapies: the low-Ca (D[Ca]?=?2.5 mEq/L; N?=?96), mid-Ca (D[Ca]?=?3.0 mEq/L; N?=?121), and high-Ca (D[Ca]?=?3.5 mEq/L; N?=?82) groups. After five years' study, only 41 patients in the low-Ca group, 34 in the mid-Ca group, and 32 in the high-Ca group completed the study. The results demonstrated that serum corrected calcium concentrations were significantly lower in the low-Ca group compared with other groups in years 3 and 4, although the products of corrected calcium time phosphate did not show difference between each group.^Δserum alkaline phosphatase (^ΔAlk-p) to baseline levels increased significantly after the fourth year in all three groups (p < 0.05). Serum ^Δ iPTH only increased significantly after the fourth year in the low-Ca group (p < 0.05) but not in the other groups. There were no significant differences in the extent of ^ΔAlk-p and ^ΔiPTH between the groups. Cox proportional methods also showed no difference in cumulative survival between the groups. In conclusion, our results demonstrate that compared with the other two groups of D[Ca], long-term use of D[Ca] of 2.5 mEq/L was associated with relatively lower serum calcium concentration. Perhaps this was related to a greater extent of iPTH concentration elevation after five years.     

Determinants of Plasma Parathyroid Hormone Levels in Young Women

While the effects of calcium, phosphorus intake, and vitamin D on parathyroid hormone (PTH) have been well studied, less is known about other factors that impact PTH. Our goal was to delineate associations between demographic, dietary, and plasma factors and PTH. We conducted a cross-sectional study of intact PTH among 1,288 nonblack women in the Nurses Health Study II aged 33–53 with BMI <30 kg/m² and eGFR ≥60 ml/min/1.73 m². Median PTH was 30.7 pg/ml. After adjusting for 25-hydroxyvitamin D and other factors, PTH was 4.1 pg/ml lower (95% CI −7.7 to −0.5) in women who smoked 1–14 cigarettes/day and 6.4 pg/ml lower (95% CI −11.2 to −1.7) in women who smoked >15 cigarettes/day compared to nonsmokers. After multivariate adjustment, women whose BMI was 27–29 kg/m² had PTH levels 2.0 pg/ml higher (95% CI 0.2–3.9) compared to BMI of 21–22 kg/m² and women in the highest quartile of plasma phosphorus had PTH levels 4.1 pg/ml lower (95% CI −5.8 to −2.4) than women in the lowest quartile. Higher vitamin A intake was independently associated with lower PTH, whereas lower calcium intake, lower plasma calcium, lower plasma 25-hydroxyvitamin D, and winter blood draw were associated with higher PTH. Intakes of phosphorus, animal protein, magnesium, alcohol, and caffeine were not associated with PTH. Factors not classically associated with calcium–phosphorus metabolism impact PTH. Additional research is needed to elucidate the mechanisms whereby smoking, vitamin A, and phosphorus affect PTH and to examine how body size and season may affect PTH independent of 25(OH)D.     

Increased Serum 1,25-Dihydroxyvitamin D after Growth Hormone Administration is not Parathyroid Hormone-Mediated

To assess the effects of growth hormone (GH) on serum 1,25-dihydroxyvitamin D [1,25(OH)₂D], we performed the following prospective crossover study in six healthy, young, adult, white men. During each of two admissions for 2? days to a general clinical research center, subjects were placed on a daily dietary calcium intake of 400 mg. Serum calcium, phosphorus, 1,25(OH)₂D, immunoreactive intact parathyroid hormone (PTH), insulin-like growth factor I (IGF-I), IGF binding protein 3 (IGFBP3), tubular reabsorption of phosphate (TRP), and maximum tubular reabsorption of phosphate (TMP/GFR) were measured. Recombinant human GH (rhGH, Humatrope) (25 μg/kg/day subcutaneously for 1 week) was administered prior to and during one of the admissions. Results are expressed as mean ± SEM. Whereas serum 1,25(OH)₂D (58.9 ± 7.7 versus 51.6 ± 7.4 pg/ml, P < 0.01), serum phosphorus (4.5 ± 0.1 versus 3.7 ± 0.1 mg/dl, P < 0.01), TRP (92.0 ± 0.5 versus 87.8 ± 0.7 mg/dl, P < 0.005), TMP/GFR (4.6 ± 0.1 versus 3.5 ± 0.2, P < 0.005), and urinary calcium (602 ± 49 versus 346 ± 25 mg/day, P < 0.001) increased significantly, serum PTH decreased significantly (19.9 ± 1.9 versus 26.8 ± 4.0 pg/ml, P < 0.05) and serum calcium did not change when subjects received rhGH. These findings indicate that in humans, GH affects serum 1,25(OH)₂D independently of circulating PTH and that this effect is mediated by IGF-I. We propose, therefore, that one potential mechanism by which GH stimulates increases in bone mass is via modest increases in serum 1,25(OH)₂D. Received: 2 May 1996 / Accepted: 18 October 1996     

Cases with Fewer than Four Parathyroid Glands in Patients withRenal Hyperparathyroidism at Initial Parathyroidectomy

In the surgical treatment of secondaryhyperparathyroidism (2HPT) due to uremia, it is considered necessary toremove all parathyroid glands from the neck to prevent persistent andrecurrent parathyroid hyperfunction. However, in some cases fewer thanfour parathyroid glands can be recognized at initial operation; in thepresent study, we evaluated the long-term prognosis and estimatedsurgical strategy in such cases. Between March 1981 and January 1999,822 patients underwent total parathyroidectomy (PTx) with forearmautograft for advanced 2HPT at the Department of Transplant Surgery of Nagoya Second Red Cross Hospital. In 21 cases (2.6%) fewer than fourparathyroid glands were macroscopically found at the initial operation.These cases were followed up and their parathyroid function wasevaluated by measurement of intact parathyroid hormone (PTH). In 20 ofthe 21 cases three glands were found, in 1 patient only two glands. In5 of these cases the fourth gland was identified first afterpostoperative histopathologic evaluation. In all these cases the intactPTH level was normalized. In 8 of the remaining 16 cases high PTHlevels persisted after the initial operation, including 3 patients who underwent neck reexploration. However, in the other 7 patients PTHlevels dropped within normal range immediately after PTx and a fourthgland has never been recognized. One patient was lost to follow-up. Thus, using our operative strategy, 12 of 822 cases (0.85%) did notdevelop persistent or recurrent HPT even though only three glands wereidentified at the operation. To avoid postoperative hypoparathyroidism,autotransplantation should be performed when fewer than four parathyroid glands are found at the initial operation.     

In Vitro Parathyroid Hormone Release in Patients with Secondary Hyperparathyroidism

Background: The purpose of this study was to determine the precise endocrim. characteristics of parathyroid function in secondary hyperparathyroidism (sHPT).
Methods: We examined the effects of extracellular ionized calcium (Ca²⁺) varying from 0.5 to 2.0 mM on parathyroid hormone (PTH) release in parathyroid cell suspensions using a mid-regional PTH assay. Cells were obtained from 26 patients with sHPT who were divided into two groups according to the type of hyperplasia they exhibited, either nodular (n=16) or diffuse [n= 10). For compdrison, we also analyzed data from nine patients with primary hyperparathyroidism (pHPT; adenomas).
Results: Significant in vitro suppression of PTH release by Ca²⁺ was observed in the majority of subjects, regardless of the histologic abnormality. The pHPT group exhibited no significant relationship between clinical and in vitro data. In contrast, in the sHPT group (taken as a whole), suppression of PTH release by Ca²⁺ exhibited a plateau at a total serum calcium concentration of 2.5 mmol/L, and a parathyroid gland weight of 2 g.
Conclusions: These findings suggest that there is a curvilinear relationship in sHPT, but not pHPT, between the in vitro calcium sensitivity of parathyroid cells and total serum calcium, as well as gland weight. The in vitro calcium sensitivity in sHPT remains constant when the total serum calcium concentration exceeds 2.5 mmol/L, or when the gland weight exceeds 2 g.     

Relationship Between Disease Activity and Serum Levels of Vitamin D Metabolites and Parathyroid Hormone in Ankylosing Spondylitis

Vertebral fractures due to osteoporosis are a common but frequently unrecognized complication of ankylosing spondylitis (AS) and various factors may contribute to the development of osteoporosis in AS. It is known that inflammatory activity in rheumatic disease (i.e., proinflammatory cytokines) itself plays a possible role in the pathophysiology of bone loss. 1,25-Dihydroxyvitamin D₃ (1,25(OH)₂D₃) seems to be another possible candidate for mediatory function in regulating both the inflammatory process and bone turnover. The aim of this study was to evaluate the relation between disease activity, bone turnover and calciotropic hormones. In 70 patients with established AS and an age- and sex-matched control group, the relation between disease activity (erythrocyte sedimentation rate, C-reactive protein, Bath Ankylosing Spondylitis Disease Activity Index), and serum levels of vitamin D metabolites, parathyroid hormone (PTH), bone alkaline phosphatase (bAP) and urinary pyridinium crosslinks were determined. Serum levels of 1,25(OH)₂D₃ (p<0.01) and PTH (p<0.01) were negatively correlated with disease activity, the excretion of urinary pyridinium crosslinks showed a positive correlation with disease activity (p<0.01), and 1,25(OH)₂D₃ and PTH were positively correlated with bAP (p<0.01). These results indicate that high disease activity in AS is associated with an alteration in vitamin D metabolism and increased bone resorption. Furthermore, the decreased levels of 1,25(OH)₂D₃ may contribute to a negative calcium balance and inhibition of bone formation. Our results suggest further research is necessary to determine whether low levels of 1,25(OH)₂D₃ as an endogenous immune modulator suppressing activated T cells and cell proliferation may accelerate the inflammation process in AS. Received: 29 January 2001 / Accepted: 3 August 2001     

Combining Early Postoperative Parathyroid Hormone and Serum Calcium Levels Allows for an Efficacious Selective Post-thyroidectomy Supplementation Treatment

Background  

Optimal treatment protocol to prevent symptomatic hypocalcemia following total thyroidectomy is still matter of debate. We prospectively evaluated the efficacy of a selective supplementation protocol based on both early postoperative intact parathyroid hormone (iPTH) and serum calcium levels.     

Intraoperative Parathyroid Hormone Monitoring in Patients with Recognized Multiglandular Primary Hyperparathyroidism

Background  

Intraoperative parathyroid hormone (IOPTH) monitoring reliably predicts cure of primary hyperparathyroidism (PHPT) due to single-gland disease. However, its utility in PHPT caused by multiple-gland disease (MGD) is still debated, for both detection and prediction of adequate resection. Our hypothesis is that once MGD is encountered during an operation, more stringent criteria for determining adequate resection can improve cure rates.