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1.  Immunoreactive Forms of Circulating Parathyroid Hormone in Primary and Ectopic Hyperparathyroidism 
Journal of Clinical Investigation  1974;54(1):175-181.
The immunoreactive forms of parathyroid hormone (iPTH) in the plasma of six patients with primary, adenomatous hyperparathyroidism and six patients with ectopic hyperparathyroidism due to non-parathyroid cancer were compared by using gel filtration on columns of Bio-Gel P-150 and radioimmunoassay of iPTH in eluted fractions after concentration. We found much less (p<0.001) small (mol wt<9,500) COOH-terminal fragments of iPTH in plasma samples from ectopic hyperparathyroid patients (0.52±0.13 ng eq/ml) than in samples from primary hyperparathyroid patients (3.70±1.15 ng eq/ml). The quantity of iPTH eluting with or before native bovine PTH [1-84] was the same in both syndromes (ectopic hyperparathyroidism, 0.82±0.22 ng eq/ml; primary hyperparathyroidism, 0.73±0.09 ng eq/ml), and these values correlated positively with plasma calcium concentration (ectopic hyperparathyroidism, r=0.908; primary hyperparathyroidism, r=0.919). In both syndromes, plasma samples had an iPTH component that eluted well before PTH [1-84] (mol wt 9,500), but this component was present in much larger quantities in three patients with ectopic hyperparathyroidism. We conclude that (a) the decreased quantity of biologically inactive COOH-terminal fragments of iPTH circulating in ectopic hyperparathyroidism accounts for the previously reported relatively lower total serum iPTH values in this syndrome as compared with primary hyperparathyroidism (Riggs et al. 1971. J. Clin. Invest. 50: 2079); (b) there appears to be sufficient iPTH with presumed biologic activity to account for the hypercalcemia in both syndromes; (c) a large PTH component, not previously recognized in plasma, is present in both ectopic and primary hyperparathyroidism and may exist as the predominant immunoreactive form of the hormone in some patients with ectopic hyperparathyroidism.
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PMCID: PMC301537  PMID: 4834887
2.  Radioimmunoassay of human parathyroid hormone in serum 
A new radioimmunoassay for human parathyroid hormone (PTH) in serum, which can measure the hormone present in 94% of the normal sera tested, is described. It is based on the ability of human PTH to compete with 131I-labeled bovine PTH for binding to an antiserum directed against porcine PTH. This antiserum distinguishes between human PTH extracted from parathyroid adenomata and that present in hyperparathyroid sera. Evidence is given to suggest that this is due to immunochemical changes in the hormone extracted from adenomata and not to immunochemical heterogeneity of the hormone present in serum.
Physiologic data supporting the validity and specificity of the assay are presented. Induced episodes of hypercalcemia and hypocalcemia resulted in appropriate responses in serum immunoreactive PTH (IPTH) in normal subjects and in patients with Paget's disease of bone. In normals, there was a progressive increase in serum IPTH in the late afternoon and evening, suggesting a diurnal secretory rhythm. A negative correlation was found between the serum calcium and serum IPTH over the normal range of serum calcium values; a positive correlation was found between these variables in patients with primary hyperparathyroidism. There was apparent overlap between serum IPTH values in normal subjects and patients with primary hyperparathyroidism, but formal discriminate analysis of values for serum calcium and IPTH demonstrated separation of these two groups, without overlap.
PMCID: PMC291890  PMID: 5543877
3.  Human Parathyroid Hormone IMMUNOLOGICAL CHARACTERIZATION OF ANTIBODIES AGAINST A GLANDULAR EXTRACT AND THE SYNTHETIC AMINO-TERMINAL FRAGMENTS 1-12 AND 1-34 AND THEIR USE IN THE DETERMINATION OF IMMUNOREACTIVE HORMONE IN HUMAN SERA 
Journal of Clinical Investigation  1974;54(6):1382-1394.
Antibodies to a urea-trichloroacetic acid extract [hPTH-(TCA)] of human parathyroid tumors and to the synthetic NH2-terminal fragments of human parathyroid hormone hPTH-(1-12) and -(1-34) were developed in goats to characterize immunochemically various PTH preparations and to estimate immunoreactive PTH (iPTH) in human sera. They were quantitated on the basis of their capacity to bind [131I]-hPTH-(1-12), [131I]hPTH-(1-34) or [131I]bovine PTH (bPTH-(1-84)). The quality of the antibodies was assessed by reference to inhibition of their interaction with labeled peptides by synthetic hPTH comprising 34 NH2-terminal amino acid residues or fragments thereof [hPTH-(1-12), -(13-34), -(18-34), -(25-34), -(18-24)] or by the Sephadex G-100-purified full-length peptide hPTH-(1-84) [hPTH-(1-84)G-100]. The synthetic peptides used in this work correspond in their structure to the NH2-terminal amino acid sequence 1-34, as elucidated by Brewer and collaborators (1972. Proc. Natl. Acad. Sci. U. S. A.69: 3583-3588). Inhibition studies were also carried out with bPTH-(1-34) and bPTH-(1-84). Anti-hPTH-(TCA) exhibited specificities directed to determinants in the COOH-terminal and NH2-terminal part of hPTH-(1-84) and exhibited cross-reactivity with bPTH-(1-84). Anti-hPTH-(1-34), on the other hand, showed immunological specificities mainly directed to antigenic determinants located in the COOH-terminal half of hPTH-(1-34). In addition, some reactivity with the NH2-terminal hPTH-(1-12) and with the extractive full-length peptides of human and bovine origin was observed. Antibodies to hPTH-(1-12) cross-reacted with hPTH-(1-34) and -(1-84)G-100.
iPTH was radioimmunologically determined in human sera by the following systems: (a) [131I]bPTH-(1-84), anti-hPTH-(TCA) and hPTH-(1-84)G-100 as standard; (b) [131I]hPTH-(1-34), anti-hPTH-(1-34) and hPTH-(1-34) as standard. With system (a), COOH-terminal fragments of hPTH-(1-84) having a molecular weight of approximately 7,000 were detected, and there was an almost total discrimination of serum iPTH levels in normal and in hyperparathyroid subjects. With system (b), on the other hand, several molecular species of iPTH were detected, including a component larger than hPTH-(1-84) and others similar to hPTH-(1-84) and to a fragment co-eluting with the NH2-terminal fragment hPTH-(1-34). When serum iPTH was assayed in system (b), there was a large overlap of iPTH levels in control subjects and in patients with primary hyperparathyroidism.
PMCID: PMC301693  PMID: 4474187
4.  Immunoheterogeneity of Parathyroid Hormone in Venous Effluent Serum from Hyperfunctioning Parathyroid Glands 
Journal of Clinical Investigation  1977;60(6):1367-1375.
The immunoreactive parathyroid hormone (iPTH) in the plasma of hyperparathyroid man consists largely of carboxyl (COOH)-terminal fragments of the hormone. Although these fragments have been thought to arise principally or solely from peripheral metabolism of intact human PTH {hPTH(1-84)} secreted from the parathyroid gland, there is disagreement about the source of iPTH fragments in vivo.
To reexamine this question, we fractionated peripheral and thyroid or parathyroid venous effluent sera from four patients with primary hyperparathyroidism using a high-resolution gel filtration system (Bio-Gel P-150 columns run by reverse flow). The column effluents were analyzed using two PTH radioimmunoassays, one directed toward the amino(NH2)-terminal region of the molecule, the other toward the COOH-terminal region.
In all four thyroid or parathyroid venous effluent sera studied, iPTH was 9-180 times higher than in peripheral serum from the same patient; after fractionation, hPTH(1-84) accounted for only a portion of the total iPTH (35-55% with the assay directed toward the COOH-terminal region of hPTH, >90% with the NH2-terminal directed assay.) The remaining iPTH eluted from Bio-Gel P-150 after hPTH(1-84) as NH2-or COOH-terminal hPTH fragments. These results suggest that parathyroid tumors secrete large quantities of hPTH fragments. Based on estimates of their molar concentrations in serum, tumor-secreted COOH-terminal hPTH fragments could account for most of these peptides in peripheral serum if their survival times were, as estimated by several other workers, 5-10 times that of hPTH(1-84).
We conclude that, in contrast to published information, secretory products of hyperfunctioning parathyroid tissue are probably a major source of serum PTH immunoheterogeneity.
PMCID: PMC372494  PMID: 915003
5.  Hypertension and hyperparathyroidism are associated with left ventricular hypertrophy in patients on hemodialysis 
Indian Journal of Nephrology  2009;19(4):153-157.
Conflicting data for association between left ventricular hypertrophy (LVH) and secondary hyperparathyroidism has been reported previously among dialysis patients. The present study was conducted to evaluate the association of hyperparathyroidism and hypertension with LVH. Charts of 130 patients on hemodialysis for at least six months were reviewed. All were subjected to M-mode echocardiography. Left ventricular mass (LVM) was calculated by Devereux's formula. LVM Index (LVMI) was calculated by dividing LVM by body surface area. Sera were analyzed for intact parathyroid hormone (iPTH). iPTH of > 32 pmol/l and a mean blood pressure (MAP) of > 107 mmHg were considered high. Patients were stratified into groups according to their MAP and iPTH. A total of (47.7%) patients were males and 68 (52.3%) were females. Their median age was 57 years. The median duration on dialysis was 26 months. Forty eight (36.9%) patients had high BP and 54 (41.5%) had high iPTH. Both high BP and high iPTH were present in 38 (29.2%) patients. Analysis of the relationship between LVM, LVMI, MAP and iPTH showed that LVM and LVMI were significantly (P < 0.001) higher in patients with concomitant high BP and high iPTH. LVMI was significantly higher in patients with high iPTH alone. Concomitant high iPTH and high MAP increase the risk of LVH in hemodialysis patients. High iPTH alone might contribute in escalating LVH. Adequate control of hypertension and hyperparathyroidism might reduce the risk of developing LVH.
doi:10.4103/0971-4065.59337
PMCID: PMC2875705  PMID: 20535251
Hemodialysis; hypertension; hyperparathyroidism; left ventricular hypertrophy
6.  The Relationship Between Technetium-99m-Methoxyisobutyl Isonitrile Parathyroid Scintigraphy and Hormonal and Biochemical Markers in Suspicion of Primary Hyperparathyroidism 
Objective: Technetium-99m-methoxyisobutyl isonitrile (Tc-99m MIBI) has been widely used to evaluate hyperfunctioning autonomous parathyroid glands in patients with elevated intact parathyroid hormone (iPTH) and/or calcium (Ca) level. The aim of this study was to evaluate the relationship between Tc-99m MIBI parathyroid scintigraphy and hormonal and biochemical markers in suspicion of primary hyperparathyroidism (PHPT).
Material and Methods: Dual-phase Tc-99m MIBI parathyroid scintigraphy and total serum iPTH, Ca, phosphorus (P) and albumin measurements were performed in 60 patients (52 females, 8 males; mean age, 59.38±12.51 years; range, 34 to 86 years) with suspicion of PHPT.
Results: The iPTH median level was 160.3 pg/mL (47.8 to 782.6). Thirty-five of the patients had surgical resection of hyperfunctioning parathyroid glands. Of the 35 patients, parathyroid gland pathology was detected in 30 patients using scintigraphic examination. Tc-99m MIBI parathyroid scintigraphy was negative in 30 patients. The iPTH, Ca and P levels were significantly different between in the Tc-99m MIBI positive group and the negative group, respectively: For iPTH, 202.1 (47.8-782.6) pg/mL versus 111.6 (80.1-373) pg/mL; p<0.001. For Ca, 11.7±1.15 mg/dL versus 10.3±1.05 mg/dL; p<0.001 and for P levels, 2.46±0.62 mg/dL versus 3.40±0.70 mg/dL; p<0.001). There was no significant difference in serum albumin levels between the MIBI positive and MIBI negative groups (4.25±0.27 g/dL versus 4.25±0.41 g/dL; p>0.05). Tc-99m MIBI parathyroid scintigraphy showed good correlation with iPTH level and histopathological diagnosis. Sensitivity and specificity was found 83.3% and 76.7%, respectively at the level of iPTH>147.7pg/mL.
Conclusion: Tc-99m MIBI parathyroid scintigraphy is most likely to produce identification and localization of a parathyroid adenoma when both iPTH and Ca are elevated as well as decreased P levels.
Conflict of interest:None declared.
doi:10.4274/Mirt.21931
PMCID: PMC3629790  PMID: 23610725
Technetium-99m sestamibi; primary hyperparathyroidism; parathyroid hormone; calcium; phosphorus
7.  Needle aspirate PTH in diagnosis of primary hyperparathyroidism due to intrathyroidal parathyroid cyst 
Summary
Parathyroid cysts are rare (0.8–3.41% of all parathyroid lesions) and usually arise secondary to cystic degeneration of parathyroid adenomas. Intrathyroidal parathyroid cysts are extremely rare with only three cases reported till date. We present a 24-year-old female with clinical and biochemical features of primary hyperparathyroidism (PHPT; Ca2 +: 12.1 mg/dl; intact parathyroid hormone (iPTH): 1283 pg/ml) and poor radiotracer uptake with minimal residual uptake in the left thyroid lobe at 2 and 4 h on Tc99m sestamibi imaging. Neck ultrasonography (USG) revealed 0.6×1 cm parathyroid posterior left lobe of thyroid along with 22×18 mm simple thyroid cyst. USG-guided fine-needle aspiration (FNA) and needle tip iPTH estimation (FNA-iPTH) from parathyroid lesion was inconclusive (114 pg/ml), necessitating FNA of thyroid cyst, which revealed high iPTH (3480 pg/ml) from the aspirate. The patient underwent a left hemithyroidectomy. A >50% drop in serum iPTH 20 min after left hemithyroidectomy (29.4 pg/ml) along with histopathology suggestive of intrathyroidal cystic parathyroid adenoma (cystic lesion lined by chief cell variant parathyroid cells without any nuclear atypia, capsular or vascular invasion surrounded by normal thyroid follicles) confirmed that the parathyroid cyst was responsible for PHPT. This report highlights the importance of FNA-iPTH in localizing and differentiating a functional parathyroid lesion from nonfunctional tissue in PHPT.
Learning points
Fine-needle aspiration from suspected parathyroid lesion and needle tip iPTH (FNA-iPTH) estimation from the saline washing has an important role in localizing primary hyperparathyroidism (PHPT).FNA-iPTH estimation may help in differentiating functional from nonfunctional parathyroid lesion responsible for PHPT.iPTH estimation from aspirate of an intrathyroid cyst is helpful in differentiating intrathyroidal parathyroid cyst from thyroid cyst.
doi:10.1530/EDM-13-0019
PMCID: PMC3922279  PMID: 24616763
8.  Effect of dietary phosphorus on circulating concentrations of 1,25-dihydroxyvitamin D and immunoreactive parathyroid hormone in children with moderate renal insufficiency. 
Journal of Clinical Investigation  1984;73(6):1580-1589.
The hyperparathyroidism characteristic of patients with moderate renal insufficiency could be caused by decreases in the plasma concentration of ionized calcium (Ca++) evoked by: (a) recurring increases in the plasma concentration of inorganic phosphorus that may be detectable only in the post-prandial period; (b) a reversible, phosphorus-mediated suppression of renal 25-hydroxyvitamin D-1 alpha-hydroxylase that decreases the plasma concentration of 1,25-dihydroxyvitamin D (1,25-(OH)2D) enough to decrease both gut absorption and bone resorption of Ca++; (c) both of these. In a group of eight children with moderate renal insufficiency, mean glomerular filtration rate (GFR) 45 +/- 4 (SE) ml/min per 1.73 M2, ages 6-17 yr, we tested these hypotheses by determining the effect of short term (5 d) restriction and supplementation of dietary intake of phosphorus on the plasma concentration of 1,25-(OH)2D, the serum concentrations of immunoreactive parathyroid hormone (iPTH) and phosphorus, and the fractional renal excretion of phosphorus ( FEPi ). When dietary phosphorus was normal, 1.2 g/d, the serum concentrations of phosphorus throughout the day were not greater than those of normal control children, and the serum concentrations of carboxyl-terminal iPTH (C-iPTH) were greater, 59 +/- 9 vs. 17 +/- 3 mu leq/ml, and unchanging; the serum concentration of intact-iPTH was also greater, 198 +/- 14 vs. 119 +/- 8 pg/ml. The plasma concentration of 1,25-(OH)2D was lower than that of age-matched controls, 27 +/- 3 vs. 36 +/- 2 pg/ml (P less than 0.01). When dietary phosphorus was restricted to 0.35 g/d, the plasma concentration of 1,25-(OH)2D increased by 60% to a mean value not different from that of normal controls, while serum concentrations of C-iPTH and intact-iPTH decreased by 25%, the latter concentration to a mean value not different from that of controls. FEPi decreased from 31 to 9%. When dietary phosphorus was supplemented to 2.4 g/d, the plasma concentration of 1,25-(OH)2D decreased 32%, while those of C-iPTH and intact-iPTH increased by 131 and 45%, respectively; FEPi increased from 27 to 53%. Plasma concentrations of 25-hydroxyvitamin D remained normal and unchanged, and GFR did not change when dietary phosphorus was manipulated. The data demonstrate that in children with moderate renal insufficiency: (a) A normal dietary intake of phosphorus in attended by a decreased circulating concentration of 1,25-(OH)2D and an increased concentration of iPTH, but not by recurring increases in the serum concentration of phosphorus at any time of the day; (b) Dietary phosphorus is, however, a major determinant of the circulating concentrations of both 1,25-(OH)2D and iPTH, which vary inversely and directly, respectively, with dietary intake of phosphorus, and increase and decrease, respectively, to normal values when phosphorus is restricted for 5 d; (c) Restriction and supplementation of dietary phosphorus induces changes in the serum concentration of iPTH that correlate strongly but inversely with those induced in the plasma concentration of 1,25-(OH)2D (r = -0.88, P < 0.001); and (d) The physiologic responsiveness of the renal tubule to changes in dietary phosphorus is to a substantial extent intact. The data provide support for the second hypothesis stated.
PMCID: PMC437069  PMID: 6547151
9.  Rapid Decrease of Intact Parathyroid Hormone Could Be a Predictor of Better Response to Cinacalcet in Hemodialysis Patients 
Yonsei Medical Journal  2013;54(2):453-463.
Purpose
Cinacalcet is effective for treating refractory secondary hyperparathyroidism (SHPT), but little is known about the response rates and clinical factors influencing the response.
Materials and Methods
A prospective, single-arm, multi-center study was performed for 24 weeks. Cinacalcet was administered to patients with intact parathyroid hormone (iPTH) level greater than 300 pg/mL. Cinacalcet was started at a dose of 25 mg daily and titrated until 100 mg to achieve a serum iPTH level <300 pg/mL (primary end point). Early response to cinacalcet was defined as a decrease of iPTH more than 50% within one month.
Results
Fifty-seven patients were examined. Based on the magnitude of iPTH decrease, patients were divided into responder (n=47, 82.5%) and non-responder (n=10, 17.5%) groups. Among the responders, 38 achieved the primary end point, whereas 9 patients showed a reduction in serum iPTH of 30% or more, but did not reach the primary end point. Compared to non-responders, responders were significantly older (p=0.026), female (p=0.041), and diabetics (p<0.001). Additionally, early response was observed more frequently in the responders (30/47, 63.8%), of whom the majority (27/30, 90.0%) achieved the primary end point. Multivariate analysis showed that lower baseline iPTH levels [odds ratio (OR) 0.96, 95% confidence interval (CI) 0.93-0.99], the presence of diabetes (OR 46.45, CI 1.92-1125.6) and early response (OR 21.54, CI 2.94-157.7) were significant clinical factors affecting achievement of iPTH target.
Conclusion
Cinacalcet was effective in most hemodialysis patients with refractory SHPT. The presence of an early response was closely associated with the achievement of target levels of iPTH.
doi:10.3349/ymj.2013.54.2.453
PMCID: PMC3575968  PMID: 23364981
Cinacalcet; end-stage renal disease; hemodialysis; parathyroid hormone; secondary hyperparathyroidism
10.  Do current screening recommendations allow for early detection of lithium-induced hyperparathyroidism in patients with bipolar disorder? 
Background
Current screening recommendations for early detection of lithium-associated hyperparathyroidism propose an exclusive measurement of serum albumin-adjusted calcium (Aac) concentration as a single first step. However, longitudinal data in patients with recurrent affective disorders suggest that increases in serum intact parathyroid hormone (iPTH) levels in lithium-treated patients may not necessarily be accompanied by a parallel increase in the concentration of Aac. If true, patients with an isolated increase in iPTH concentration above the reference range might be missed following current screening recommendations. Therefore, this study set out to examine key parameters of calcium metabolism, including iPTH and 25-hydroxycholecalciferol concentrations in patients with bipolar disorder that was or was not managed with lithium.
Methods
Sixty patients with bipolar disorder according to DSM-IV were enrolled, 30 of whom had received long-term lithium treatment (lithium group), whereas the other 30 patients were on psychopharmacological treatment not including lithium (non-lithium group) at the time of the study. Owing to exclusion criteria (e.g., lithium < 6 months, laboratory results indicative of secondary hyperparathyroidism), 23 bipolar patients composed the final lithium group, whereas 28 patients remained in the non-lithium group for statistical analyses.
Results
Patients in the lithium group showed a significantly higher concentration of iPTH compared to the non-lithium group (p < 0.05). Similarly, Aac concentrations were significantly increased in the lithium group compared to the non-lithium group (p < 0.05). However, in a multivariate linear regression model, group affiliation only predicted iPTH concentration (p < 0.05). In line with this, none of the four patients in the lithium group with an iPTH concentration above the reference range had an Aac concentration above the reference range.
Discussion
This study suggests that the biochemical characteristics between primary hyperparathyroidism and lithium-induced hyperparathyroidism differ substantially with regard to regulation of calcium homeostasis. As such, current screening practice does not reliably detect iPTH concentrations above the reference range. Therefore, further research is needed to elucidate the consequences of an isolated iPTH concentration above the reference range in order to develop the most appropriate screening tools for hyperparathyroidism in lithium-treated patients with bipolar disorder.
doi:10.1186/2194-7511-1-7
PMCID: PMC4230432  PMID: 25505674
Bipolar disorder; Lithium; Hyperparathyroidism; Calcium
11.  Perioperative Management Difficulties in Parathyroidectomy for Primary Versus Secondary and Tertiary Hyperparathyroidism 
Mædica  2012;7(2):117-124.
ABSTRACT
Background: In patients with hyperparathyroidism, parathyroidectomy is the only curative therapy. Anaesthetic management differs function of etiology (primary vs. secondary or tertiary hyperparathyroidism) and surgical technique (minimally invasive or classic parathyroidectomy).
Objectives: To evaluate peri-operative management (focusing on hemodynamic changes, cardiac arrhythmias and patients’ awakening quality) in parathyroidectomy for hyperparathyroidism of various etiologies, in a tertiary center.
Material and methods: 292 patients who underwent surgery for hyperparathyroidism between 2000-2011 were retrospectively reviewed; 96 patients (19M/77F) presented with primary hyperparathyroidism (group A) and 196 (80M/116F) with secondary and tertiary hyperparathyroidism due to renal failure (group B). Biochemical parameters (serum calcium, phosphate, creatinine) were determined by automated standard laboratory methods. Serum intact PTH was measured by ELISA (iPTH - normal range: 15-65 pg/mL).
Outcomes: Median surgery duration was 30 minutes in group A (minimally invasive or classic parathyroidectomy) and 75 minutes in group B (total parathyroidectomy and re implantation of a small parathyroid fragment into the sternocleidomastoid muscle). During anaesthesia induction, arterial hypotension developed significantly more frequent in group B (57 out of 196 pts, 29.1%) than in group A (8 out of 96 pts, 8.34%), p<0.0001, especially in patients receiving Fentanyl-Propofol. During surgery and anaesthesia maintenance, bradycardia was significantly more frequent in group A (67 out of 96 pts, 69.8%) than in group B (26 out of 196 pts, 13.3%), p<0.0001, especially during searching of parathyroid glands. By contrary, ventricular premature beats were less frequent in group A (25 out of 96 pts, 25.25%) than in group B (84 out of 196 pts, 42.85%), p=0.003. There were no statistically significant differences between the studied group regarding frequency of arterial hypertension and hypotension, paroxysmal atrial fibrillation.
Conclusions: anaesthetic management in parathyroid surgery may be difficult because of cardiac arrhythmias (bradycardia in primary hyperparathyroidism and ventricular premature beats in secondary and tertiary hyperparathyroidism, respectively) and arterial hypotension during anaesthesia induction in patients with secondary and tertiary hyperparathyroidism.
PMCID: PMC3557418  PMID: 23399537
hyperparathyroidism; parathyroidectomy; anaesthesia; arrhythmias; arterial hypotension
12.  A randomized, double-blind, placebo-controlled trial of calcium acetate on serum phosphorus concentrations in patients with advanced non-dialysis-dependent chronic kidney disease 
BMC Nephrology  2011;12:9.
Background
Hyperphosphatemia in patients with chronic kidney disease (CKD) contributes to secondary hyperparathyroidism, soft tissue calcification, and increased mortality risk. This trial was conducted to examine the efficacy and safety of calcium acetate in controlling serum phosphorus in pre-dialysis patients with CKD.
Methods
In this randomized, double-blind, placebo-controlled trial, 110 nondialyzed patients from 34 sites with estimated GFR < 30 mL/min/1.73 m2 and serum phosphorus > 4.5 mg/dL were randomized to calcium acetate or placebo for 12 weeks. The dose of study drugs was titrated to achieve target serum phosphorus of 2.7-4.5 mg/dL. Serum phosphorus, calcium, iPTH, bicarbonate and serum albumin were measured at baseline and every 2 weeks for the 12 week study period. The primary efficacy endpoint was serum phosphorus at 12 weeks. Secondary endpoints were to measure serum calcium and intact parathyroid hormone (iPTH) levels.
Results
At 12 weeks, serum phosphorus concentration was significantly lower in the calcium acetate group compared to the placebo group (4.4 ± 1.2 mg/dL vs. 5.1 ± 1.4 mg/dL; p = 0.04). The albumin-adjusted serum calcium concentration was significantly higher (9.5 ± 0.8 vs. 8.8 ± 0.8; p < 0.001) and iPTH was significantly lower in the calcium acetate group compared to placebo (150 ± 157 vs. 351 ± 292 pg/mL respectively; p < 0.001). At 12 weeks, the proportions of subjects who had hypocalcemia were 5.4% and 19.5% for the calcium acetate and the placebo groups, respectively, while the proportions of those with hypercalcemia were 13.5% and 0%, respectively. Adverse events did not differ between the treatment groups.
Conclusions
In CKD patients not yet on dialysis, calcium acetate was effective in reducing serum phosphorus and iPTH over a 12 week period.
Trial Registration
www.clinicaltrials.gov NCT00211978.
doi:10.1186/1471-2369-12-9
PMCID: PMC3055808  PMID: 21324193
13.  Correlates of parathyroid hormone concentration in hemodialysis patients 
Nephrology Dialysis Transplantation  2013;28(6):1516-1525.
Background
The implications of chemical hyperparathyroidism on bone and mineral metabolism measures in maintenance hemodialysis (MHD) are not well known. We hypothesized that a higher serum intact parathyroid hormone (iPTH) level is associated with the higher likelihood of hyperphosphatemia, hyperphosphatasemia [high serum alkaline phosphatase (ALP) levels] and hypercalcemia.
Methods
Over an 8-year period (July 2001–June 2009), we identified 106 760 MHD patients with iPTH and calcium (Ca), phosphorous (P) and ALP data from a large dialysis clinic. Logistic regression models were examined to assess the association between serum iPTH increments and the likelihood of hyperphosphatemia (P ≥5.5 mg/dL), hypercalcemia (Ca ≥10.2 mg/dL) and hyperphosphatasemia (ALP ≥120 U/L).
Results
Patients were 61 ± 16 years old and included 45% women, 59% diabetics and 33% Blacks. Compared with an iPTH level of 100 to <200 pg/mL, patients with an iPTH level of 600–700, 700 to <800 and ≥800 pg/mL had 122% (OR: 2.22, 95% CI: 2.04–2.41), 153% (OR: 2.53, 95% CI: 2.29–2.80) and 243% (OR: 3.43, 95% CI: 3.22–3.66) higher risk of hyperphosphatemia, respectively, and had 109% (OR: 2.09, 95% CI: 1.93–2.26), 130% (OR: 2.30, 95% CI: 2.10–2.52) and 376% (OR: 4.76, 95% CI: 4.50–5.04) higher risk of hyperphosphatasemia, respectively. Compared with an iPTH level of 100 to <200 pg/mL, both the low iPTH (<100 pg/mL, OR: 2.45, 95% CI: 2.27–2.64) and the high iPTH (≥800 pg/mL: OR: 2.13, 95% CI: 1.95–2.33) levels were associated with hypercalcemia.
Conclusions
Higher levels of iPTH are incremental correlates of hyperphosphatemia and hyperphosphatasemia, whereas both very low and high PTH levels are linked to hypercalcemia. If these associations are causal, correction of hyperparathyroidism may have overarching implications on bone and mineral disorders in MHD patients.
doi:10.1093/ndt/gfs598
PMCID: PMC3685307  PMID: 23348879
hemodialysis; serum alkaline phosphatase; serum calcium; serum intact parathyroid hormone; serum phosphorous
14.  Efficacy and safety of oral doxercalciferol in the management of secondary hyperparathyroidism in chronic kidney disease stage 4 
Indian Journal of Nephrology  2013;23(4):271-275.
This study was carried out to evaluate the efficacy and safety of doxercalciferol as therapy for secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD) stage 4 in a prospective clinical trial. A total of 35 CKD-4 patients who had a baseline parathyroid hormone (iPTH) >150 pg/mL and had not received any vitamin D analog in the preceding 8 weeks were followed up at intervals of 6 weeks for 18 weeks on oral therapy with doxercalciferol. The starting dose was 1.5 μg/day, and the dose was increased in steps of 1 μg/day if iPTH did not decrease by at least 30% on the subsequent visit. Doxercalciferol was stopped temporarily if low iPTH (<70 pg/mL), hypercalcemia (>10.7 mg/dL), or severe hyperphosphatemia (>8.0 mg/dL) occurred, and was restarted at a lower dose on reversal of these abnormalities. Calcium acetate was the only phosphate binder used. Mean iPTH decreased by 35.4 ± 4.4% from 381.7 ± 31.3 pg/mL to 237.9 ± 25.7 pg/mL (P < 0.001). The proportion of patients who achieved 30% and 50% suppression of iPTH levels was 83% and 72%, respectively. Mean serum calcium, phosphorus, and calcium-phosphorus product values did not differ significantly from the baseline values. Four, two, and nine patients developed hypercalcemia, severe hyperphosphatemia, and high CaxP (>55), respectively. Almost all patients recovered to an acceptable level within 2 weeks of stopping doxercalciferol and adjusting the phosphate binder dose. In all, 21 patients required temporary stoppage of therapy. Most of them were restarted on therapy at a reduced dose during the study. It can, therefore, be concluded that doxercalciferol is effective in controlling SHPT in CKD-4 patients with an acceptable risk of hyperphosphatemia and hypercalcemia.
doi:10.4103/0971-4065.114492
PMCID: PMC3741971  PMID: 23960343
Chronic kidney disease; doxercalciferol; parathyroid hormone; pre-dialysis; secondary hyperparathyroidism; vitamin D
15.  Vitamin D Deficiency and Secondary Hyperparathyroidism Are Common Complications in Patients with Peripheral Arterial Disease 
OBJECTIVE
To investigate via the vitamin D status whether patients with peripheral arterial disease (PAD) tend to develop vitamin D deficiency that in turn influences their clinical symptoms.
DESIGN
Cross-sectional.
SETTING
University hospital.
PATIENTS AND PARTICIPANTS
Three hundred twenty-seven patients were evaluated; subjects with secondary causes of bone disease or bone active medication were excluded. One hundred sixty-one patients with either PAD stage II (n = 84) or stage IV (n = 77) were enrolled and compared to 45 age- and sex-matched healthy controls.
MEASUREMENTS AND MAIN RESULTS
All patients underwent determinations of serum chemistry, 25-hydroxyvitamin D (vitamin D3) intact parathyroid hormone (iPTH), alkaline phosphatase (ALP), and osteocalcin and were further stratified according to an individual restriction score into 3 groups: mildly, moderately, or severely restricted in daily life due to the underlying disease. Patients with PAD IV showed significantly lower vitamin D3 (P = .0001), and calcium (P = .0001) values and significantly higher iPTH (P = .0001), osteocalcin (P = .0001) and ALP (P = .02) levels as compared to patients with PAD II. Patients considering themselves as severely restricted due to the underlying disease showed lower vitamin D3 and higher iPTH levels than those who described only a moderate (vitamin D3: P < .001; iPTH: P < .01) or mild (vitamin D3: P < .001; iPTH: P < .001) restriction in daily life.
CONCLUSION
Patients with PAD IV, especially those who feel severely restricted due to the disease, are at high risk of developing vitamin D deficiency, secondary hyperparathyroidism, and ultimately osteomalacia due to immobilization and subsequent lack of exposure to sunlight, all of which in turn lead to further deterioration. Monitoring of vitamin D metabolism and vitamin D replacement therapy could be a simple, inexpensive approach to mitigating clinical symptoms and improving quality of life in patients with advanced PAD.
doi:10.1046/j.1525-1497.2002.11033.x
PMCID: PMC1495101  PMID: 12220361
vitamin D3; secondary hyperparathyroidism; osteomalacia; immobilization; peripheral arterial disease
16.  Limited role for intraoperative intact PTH measurement in parathyroid surgery. 
Primary hyperparathyroidism may be cured surgically by complete excision of abnormal parathyroid tissue. Reoperation for persistent hypercalcaemia due to residual abnormal parathyroid tissue may be associated with a high complication rate. It is possible to assay intact parathormone (iPTH) intraoperatively and as iPTH has a relatively short half-life, its measurement intraoperatively may be used to predict successful parathyroidectomy. We have studied intraoperative iPTH levels in a consecutive series of 33 patients undergoing surgery for primary hyperparathyroidism. We found that iPTH levels fell significantly (P < 0.05) from a median pre-excision level of 122 pg/ml to a median level of 36 pg/ml 20 min after excision. However, in 3/31 successful parathyroidectomies, the intraoperative iPTH levels either remained unchanged or had risen. Reliance on intraoperative iPTH levels in these patients may have resulted in unnecessary re-exploration. We conclude that intraoperative iPTH measurement has limited usefulness as a predictor of successful parathyroidectomy for primary hyperparathyroidism.
PMCID: PMC2502514  PMID: 7717640
17.  Successful cinacalcet treatment of refractory secondary hyperparathyroidism due to multiple lung parathyroid adenomas 
NDT Plus  2009;3(1):60-63.
We describe a 56-year-old woman who presented with end-stage renal disease due to pregnancy-induced hypertension and secondary hyperparathyroidism (sHPT). She had started hemodialysis and underwent a subtotal parathyroidectomy (PTx). However, intact parathyroid hormone (iPTH) levels increased gradually. Eventually, she underwent a second PTx. However, therapy failed to significantly decrease iPTH levels. A third PTx was performed, but no pathological parathyroid tissue was found. Computed tomography scan indicated the presence of multiple ectopic lung nodules and 26 nodules were surgically removed from the left lung. Despite surgical treatment, iPTH levels remained high. Additional maxacalcitol failed to decrease iPTH levels, cinacalcet was then started. iPTH levels decreased and the cinacalcet dose could be reduced to maintenance doses of 60 mg/day. Throughout the 1.6 years of treatment, serum iPTH, alkaline phosphatase (ALP) and bone alkaline phosphatase (BAP) were normalized. As a consequence, bone pain gradually disappeared. Bone mineral density (BMD) was improved by administration of cinacalcet. In conclusion, cinacalcet was effective in this patient with refractory and inoperable sHPT. In addition, it improves their BMD and relieves bone pain.
doi:10.1093/ndtplus/sfp116
PMCID: PMC4421561  PMID: 25984040
cinacalcet; haemodialysis; hyperparathyroidism; ectopic parathyroid adenoma
18.  The current status of intraoperative iPTH assay in surgery for primary hyperparathyroidism 
Gland Surgery  2015;4(1):36-43.
Intraoperative intact parathyroid hormone (iPTH) monitoring has been accepted by many centers specializing in parathyroid surgery as a useful adjunct during surgery for primary hyperparathyroidism. This method can be utilized in three discreet modes of application: (I) to guide surgical decisions during parathyroidectomy in one of the following clinical contexts: (i) to confirm complete removal of all hyperfunctioning parathyroid tissue, which allows for termination of surgery with confidence that the hyperparathyroid state has been successfully corrected; (ii) to identify patients with additional hyperfunctioning parathyroid tissue following the incomplete removal of diseased parathyroid/s, which necessitates extended neck exploration in order to minimize the risk of operative failure; (II) to differentiate parathyroid from non-parathyroid tissue by iPTH measurement in the fine-needle aspiration washout; (III) to lateralize the side of the neck harboring hyperfunctioning parathyroid tissue by determination of jugular venous gradient in patients with negative or discordant preoperative imaging studies, in order to increase the number of patients eligible for unilateral neck exploration. There are many advantages of minimally invasive parathyroidectomy guided by intraoperative iPTH monitoring, including focused dissection in order to remove the image-indexed parathyroid adenoma with a similar or even higher operative success rate, lower prevalence of complications and shorter operative time when compared to conventional bilateral neck exploration. However, to achieve such excellent results, the surgeon needs to be aware of hormone dynamics during parathyroidectomy and carefully choose the protocol and interpretation criteria that best fit the individual practice. Understanding the nuances of intraoperative iPTH monitoring allows the surgeon for achieving intraoperative confidence in predicting operative success and preventing failure in cases of unsuspected multiglandular disease, while safely limiting neck exploration in the majority of patients with sporadic primary hyperparathyroidism. Thus, parathyroidectomy guided by intraoperative iPTH monitoring for the management of sporadic primary hyperparathyroidism is an ideal option for the treatment of this disease entity. However, the cost-benefit aspects of the standard application of this method still remain a matter of controversy.
doi:10.3978/j.issn.2227-684X.2015.01.01
PMCID: PMC4321047  PMID: 25713778
Primary hyperparathyroidism; intraoperative intact parathyroid hormone (iPTH) assay; a solitary parathyroid adenoma; multiglandular parathyroid disease
19.  Reversal of Secondary Hyperparathyroidism by Cimetidine in Chronically Uremic Dogs 
Journal of Clinical Investigation  1981;67(6):1753-1760.
Chronic cimetidine therapy has been shown to suppress circulating concentrations of immunoreactive parathyroid hormone (iPTH) in hemodialysis patients. To evaluate the long-term metabolic effects of cimetidine treatment, we studied seven chronically uremic dogs for 20 wk. The dogs were studied under metabolic conditions before, during, and after cimetidine therapy. iPTH fell progressively in the five treated dogs from 536±70 μleq/ml (mean±SE) (nl < 100 μleq/ml) before treatment to 291±25 μleq/ml at 12 wk (P < 0.001) and 157±32 μleq/ml at 20 wk (P < 0.001). The control dogs showed no consistent change in iPTH. The fall in iPTH was not associated with a change in serum ionized calcium. However, serum phosphorus decreased from 5.7±0.9 mg/dl to 3.4±0.2 mg/dl by the 20th wk (P < 0.05). By contrast, the serum concentration of 1,25-dihydroxycholecalciferol increased in all treated dogs from 33.4±4.3 pg/ml to 51.8±2.4 pg/ml during treatment (P < 0.01). Calcium balance was negative in all seven dogs before cimetidine (−347±84 mg/72 h) and remained so in the control dogs; it became positive in the five treated dogs after 12 wk (1,141±409 mg/72 h) (P < 0.05). Phosphorus balance, 24-h fractional phosphate excretion, and creatinine clearance remained unchanged. Pooled samples of serum obtained during the control and 20th wk of therapy were fractionated by gel filtration and the eluates assayed for immunoreactivity. The decrease in iPTH was associated with a decrease in all the immunoreactive species, indicating suppression of parathyroid gland secretion.
These observations indicate that cimetidine suppressed circulating concentration of biologically active parathyroid hormone. A probable net decrease in the loss of phosphorus from bone to blood ensued, resulting in a fall in serum phosphorus. This may have stimulated synthesis of 1,25-dihydroxycholecalciferol and led to a positive calcium balance, thereby maintaining the serum ionized calcium concentration. The maintenance of phosphate balance, despite suppression of iPTH by cimetidine, indicates that factors other than hyperparathyroidism relate to phosphate homeostasis in chronically uremic dogs.
PMCID: PMC370753  PMID: 7240419
20.  Relationship between the Serum Parathyroid Hormone and Magnesium Levels in Continuous Ambulatory Peritoneal Dialysis (CAPD) Patients using Low-magnesium Peritoneal Dialysate 
Background
Patients on continuous ambulatory peritoneal dialysis (CAPD) have increased risk of low-turnover bone disease and relative hypoparathyroidism. Recently, it has been believed that magnesium plays an important role in regulating secretion of parathyroid hormone (PTH). The aim of this study was to evaluate the relationship between serum PTH and serum magnesium as a factor increasing the frequency of relative hypoparathyroidism.
Methods
We analyzed the data of 56 patients who had been on CAPD for more than 6 months without any significant problems. No patient had been previously treated with vitamin D or aluminum hydroxide. The patients had used peritoneal dialysate with the magnesium concentration of 0.5 mEq/L. Biochemical parameters, such as BUN, creatinine, alkaline phosphatase bony isoenzyme, total protein, albumin, total calcium, ionized calcium and intact parathyroid hormone level were measured.
Results
The mean serum magnesium level was 1,99±0.36 mEq/L. Among total 56 patients, 15 patients (26.8%) showed hypermagnesemia (serum magnesium >2.2 mEq/L) and 5 patients (8.9%) showed hypomagnesemia (serum magnesium <1.6 mEq/L). Among all 56 patients, serum iPTH (intact PTH) level was not correlated with serum magnesium level. However, it was inversely correlated with serum total calcium and ionized calcium levels, respectively (r = − 0.365, p = 0.006; r = − 0.515 p < 0.001). Among 49 patients whose serum iPTH level was less than 300 pg/mL, serum iPTH level was inversely correlated with serum magnesium level (r = − 0.295, p=0.039) and inversely correlated with serum total calcium and ionized calcium levels, respectively (r = − 0.546, p < 0.001; r = − 0.572 p < 0.001). Among 49 patients whose serum iPTH level was less than 300 pg/mL, lower iPTH group (serum iPTH < 120 pg/mL) showed higher serum magnesium level (p = 0.037), higher serum total calcium level (p < 0.001) and lower bone isoenzyme of alkaline phosphatase level (p < 0.001) than those of higher iPTH group (120 pg/mL≤serum iPTH < 300 pg/mL).
Conclusion
Among the CAPD patients whose serum iPTH level was less than 300 pg/mL, there was a significant inverse correlation between serum iPTH level and serum magnesium level. This study indicates that not only serum calcium level but also serum magnesium level are important in the regulation of serum iPTH levels of CAPD patients who have been dialyzed by low-magnesium peritoneal dialysate.
doi:10.3904/kjim.2002.17.2.114
PMCID: PMC4531662  PMID: 12164088
Magnesium; Calcium; PTH; Parathyroid hormone; Renal osteodystrophy; Calcium sensing receptor
21.  Effects of paricalcitol on calcium and phosphate metabolism and markers of bone health in patients with diabetic nephropathy: results of the VITAL study 
Nephrology Dialysis Transplantation  2013;28(9):2260-2268.
Background
Chronic kidney disease (CKD) is associated with elevations in serum phosphate, calcium–phosphorus product and bone-specific alkaline phosphatase (BAP), with attendant risks of cardiovascular and bone disorders. Active vitamin D can suppress parathyroid hormone (PTH), but may raise serum calcium and phosphate concentrations. Paricalcitol, a selective vitamin D activator, suppressed PTH in CKD patients (stages 3 and 4) with secondary hyperparathyroidism (SHPT) with minimal changes in calcium and phosphate metabolism.
Methods
The VITAL study enrolled patients with CKD stages 2–4. We examined the effect and relationship of paricalcitol to calcium and phosphate metabolism and bone markers in a post hoc analysis of VITAL. The study comprised patients with diabetic nephropathy enrolled in a double-blind, placebo-controlled, randomized trial of paricalcitol (1 or 2 μg/day). Urinary and serum calcium and phosphate, serum BAP, and intact PTH (iPTH) concentrations were measured throughout the study.
Results
Baseline demographics and calcium, phosphate, PTH (49% with iPTH <70 pg/mL), and BAP concentrations were similar between groups. A transient, modest yet significant increase in phosphate was observed for paricalcitol 2 μg/day (+0.29 mg/dL; P < 0.001). Dose-dependent increases in serum and urinary calcium were observed; however, there were few cases of hypercalcemia: one in the 1-μg/day group (1.1%) and three in the 2-μg/day group (3.2%). Significant reductions in BAP were observed that persisted for 60 days after paricalcitol discontinuation (P < 0.001 for combined paricalcitol groups versus placebo). Paricalcitol dose-dependent reductions in iPTH were observed. Paricalcitol in CKD patients (±SHPT) was associated with modest increases in calcium and phosphate.
Conclusion
Paricalcitol reduces BAP levels, which may be beneficial for reducing vascular calcification.
Trial registration
Trial is registered with ClinicalTrials.gov, number NCT00421733.
doi:10.1093/ndt/gft227
PMCID: PMC3769981  PMID: 23787544
bone-specific alkaline phosphatase; calcitriol; hypercalcemia; hyperphosphatemia; paricalcitol; vitamin D receptor activation
22.  Oral paricalcitol (19-nor-1,25-dihydroxyvitamin D2) in women receiving chemotherapy for metastatic breast cancer 
Cancer Biology & Therapy  2013;14(6):476-480.
The vitamin D hormone, [1,25(OH)2D, calcitriol], inhibits proliferation and angiogenesis in breast cancer but its therapeutic use is limited by hypercalcemia. Synthetic analogs of 1,25(OH)2D that are less calcemic, such as paricalcitol (19-nor-1,25-Dihydroxyvitamin D2), are used to treat hyperparathyroidism associated with chronic kidney disease. We sought to determine the safety and feasibility of taking oral paricalcitol with taxane-based chemotherapy in women with metastatic breast cancer (MBC). Oral paricalcitol was considered safe if it did not result in excessive toxicity, defined as grade 3 or higher serum calcium levels. It was considered feasible if the majority of women could take eight weeks of continuous therapy in the first three months. Serum calcium was monitored weekly and the paricalcitol dose was adjusted based on its calcemic effect. Intact parathyroid hormone (iPTH) was monitored as a marker of paricalcitol activity. Twenty-four women with MBC were enrolled. Twenty women (83%) received eight weeks of continuous therapy. Paricalcitol was well-tolerated with no instances of hypercalcemia grade 2 or greater. Fourteen women (54%) were able to escalate the dose. The dose range of paricalcitol in the first 3 mo was 2–7 ug/day. Serum iPTH levels at baseline were significantly higher in women with serum 25-Hydroxyvitamin D (25-OHD) levels less than 30 ng/ml (96.4 ± 40.9 pg/ml) vs. 46.2 ± 20.3 pg/ml (p = 0 0.001) (iPTH reference 12–72 pg/ml). We conclude that paricalcitol is safe and feasible in women with MBC who are receiving chemotherapy.
doi:10.4161/cbt.24350
PMCID: PMC3813563  PMID: 23760489
vitamin D; metastatic breast cancer; paricalcitol; cancer treatment
23.  Nephrogenous Cyclic Adenosine Monophosphate as a Parathyroid Function Test 
Journal of Clinical Investigation  1977;60(4):771-783.
Nephrogenous cyclic AMP (NcAMP), total cyclic AMP excretion (UcAMP), and plasma immunoreactive parathyroid hormone (iPTH), determined with a multivalent antiserum, were prospectively measured in 55 control subjects, 57 patients with primary hyperparathyroidism (1°HPT), and 10 patients with chronic hypoparathyroidism.
In the group with 1° HPT, NcAMP was elevated in 52 patients (91%), and similar elevations were noted in subgroups of 26 patients with mild (serum calcium ≤10.7 mg/dl) or intermittent hypercalcemia, 19 patients with mild renal insufficiency (mean glomerular filtration rate, 64 ml/min), and 10 patients with moderate renal insufficiency (mean glomerular filtration rate, 43 ml/min). Plasma iPTH was increased in 41 patients (73%).
The development of a parametric expression for UcAMP was found to be critically important in the clinical interpretation of results for total cAMP excretion. Because of renal impairment in a large number of patients, the absolute excretion rate of cAMP correlated poorly with the hyperparathyroid state. Expressed as a function of creatinine excretion, UcAMP was elevated in 81% of patients with 1° HPT, but the nonparametric nature of the expression led to a number of interpretive difficulties. The expression of cAMP excretion as a function of glomerular filtration rate was developed on the basis of the unique features of cAMP clearance in man, and this expression, which provided elevated values in 51 (89%) of the patients with 1° HPT, avoided entirely the inadequacies of alternative expressions.
Results for NcAMP and UcAMP in nonazotemic and azotemic patients with hypoparathyroidism confirmed the validity of the measurements and the expressions employed.
PMCID: PMC372425  PMID: 197123
24.  The prevalence of hypovitaminosis D and secondary hyperparathyroidism in obese Black Americans 
Clinical endocrinology  2006;64(5):523-529.
Summary
Context Both obesity (body mass index, BMI ≥ 30 kg/m2) and Black race are associated with a higher risk of vitamin D deficiency and secondary hyperparathyroidism. We hypothesized the risk of hypovitaminosis D would therefore be extraordinarily high in obese Black adults.
Objective
To study the effects of race and adiposity on 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (iPTH).
Design, Setting and Participants
Cross-sectional study of 379 Black and White adults from the Washington D.C. area. BMI ranged from 19.9 to 58.2 kg/m2.
Main Outcome Measures
Prevalence of hypovitaminosis D [25(OH)D < 37.5 nmol/l] and secondary hyperparathyroidism [25(OH)D < 37.5 nmol/l with iPTH > 4.2 pmol/l].
Results
Obese Black subjects had lower mean 25(OH)D, 40.3 (SD, 20.3) nmol/l, compared with obese Whites, 64.5 (29.7), P < 0.001, nonobese Blacks, 53.3 (26.0), P = 0.0025 and nonobese Whites, 78.0 (33.5), P < 0.001. The prevalence of hypovitaminosis D increased with increasing BMI, and was greater (P < 0.001) in Blacks than Whites within all BMI categories examined. Among subjects with BMI ≥ 35 kg/m2, 59% of Blacks vs 18% of Whites had hypovitaminosis D (odds ratio 6.5, 95% confidence interval 3.0–14.2). iPTH was negatively correlated with 25(OH)D (r = −0.31, P < 0.0001), suggesting those with hypovitaminosis D had clinically important vitamin D deficiency with secondary hyperparathyroidism. For secondary hyperparathyroidism 35.2% of Blacks met the criteria, compared to 9.7% of Whites (OR 3.6, CI 1.5–98.8).
Conclusions
Obese Black Americans are at particularly high risk for vitamin D deficiency and secondary hyperparathyroidism. Physicians should consider routinely supplementing such patients with vitamin D or screening them for hypovitaminosis D.
doi:10.1111/j.1365-2265.2006.02502.x
PMCID: PMC1863008  PMID: 16649971
25.  The pattern of the descent of PTH measured by intraoperative monitoring of intact-PTH in surgery for renal hyperparathyroidism 
The Indian Journal of Surgery  2008;70(2):62-67.
Background
In the setting of total parathyroidectomy and autotransplantation surgery (TPTxAS) treatment for secondary hyperparathyroidism (SHPT) we evaluated whether intraoperative parathyroid hormone (iPTH) monitoring is an useful tool as a reference for total parathyroid removal.
Design
Prospective open single value measurement efficacy study of one intraoperative (i.o.) diagnostic monitoring method (iPTH) on a cohort of surgical patients.
Patients
All patients (n = 35) undergoing TP and SCTx at the Department of Surgery, Donostia Hospital from January 2002 to December 2006.
Main outcome measures
Serum levels of iPTH during surgery and prediction time of the of descent of PTH levels (measured in the clinic, at admission day and intra-operatively during induction of anesthesia, and every 5 and 10 minutes after removal of adenoma and 24 hours thereafter) were analyzed.
Results
iPTH levels dropped clearly at ten minutes in all 35 patients and were non-measurable at 24 hours. iPTH decreased from pathological (1302.24 + 424.9 pg/ml) to half (50%) the values at the third intra-operative determination — minute 10 − (614.8 ± 196.62) and was undetectable at 24 hours.
Conclusions
Intra-operative measurement of iPTH is useful in the prediction of complete removal of all parathyroid tissue prior to autotransplantation thus avoiding persistence because of incomplete surgery.
doi:10.1007/s12262-008-0017-9
PMCID: PMC3452396  PMID: 23133023
Total parathyroidectomy; Autotransplantation surgery; Secondary hyperthyroidism; Parathyroid hormone

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